JP4846439B2 - Vehicle suspension system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance practical use of a vehicular suspension system provided with a solenoid type absorber. <P>SOLUTION: Between the solenoid type absorber 18 and a lower arm 14, a damper device 20 for elastically connecting them and giving damping force in a direction that they approaches/leaves is arranged. The damper device 20 is a structure that the damping force is given by a solenoid type motor 82 and controls the damping force by controlling the motor. Relative to non-suspended high frequency vibration, it can be effectively absorbed by weakening the damping force, and further, relative to non-suspended and suspended relative vibration of relatively low frequency and large amplitude, the absorber is effectively functioned by enhancing support force of the absorber by strengthening the damping force and stability of a vehicle body can be enhanced. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a vehicle suspension system for suspending a vehicle body on wheels.

BACKGROUND ART A vehicle suspension system is a system that suspends a vehicle body on wheels, and is generally between an unsprung member such as a suspension arm and an unsprung member that is a part of the vehicle body (for example, an upper portion of a tire housing). 2. Description of the Related Art A system including a suspension spring disposed on a base plate and an absorber for connecting the unsprung member and the unsprung member to generate a damping force with respect to their approaching / separating motion is well known. In such a suspension system, an elastic connection mechanism that elastically connects the unsprung member or sprung member and the absorber, and relative movement between the sprung member or unsprung member and the absorber. It has been studied to provide a damping force applying device for applying a damping force. Regarding a suspension system provided with such an elastic coupling mechanism and a damping force application device, for example, there is a system described in the following patent document.
JP-A-8-197931

  The suspension system described in the above-mentioned patent document is a system that includes an electromagnetic motor that is an electromagnetic actuator and includes an electromagnetic absorber that generates a damping force that depends on the force of the motor. In order to avoid a motor lock phenomenon when an impact load is input, the elastic coupling mechanism and the damping force applying device are provided. The elastic coupling mechanism and the damping force imparting device listed here are examples, but these mechanisms and devices function effectively in improving the characteristics of the suspension system. However, the suspension system including the elastic coupling mechanism and the damping force imparting device leaves much room for improvement in terms of practicality. The present invention has been made in view of such circumstances, and an object thereof is to provide a highly practical suspension system.

In order to solve the above-described problems, a suspension system according to the present invention is provided between a suspension spring, an electromagnetic absorber, one member of an unsprung member and an unsprung member, and an absorber. An elastic coupling mechanism that elastically couples and an approaching / separating direction force applying device that applies an approaching / separating direction force that is a force in the approaching / separating direction (the damping force generating device is an example thereof), toward and away from the direction force imparting device, is intended to impart toward and away from the direction force by the force electromagnetic actuating device is generated, the system has a control device for controlling the vehicle distance direction force, is a control system The approaching / separating direction force having a neutral direction force as a component in the direction in which the distance between the one member and the absorber in the approaching / separating direction approaches the neutral interval is controlled. And an approaching / separating direction force changing unit that changes the approaching / separating direction force, and the approaching / separating direction force changing unit increases the neutral direction force in a state where the turning amount of the vehicle body increases, The approaching / separating direction force is changed so as to reduce the neutral direction force in a small state .

The approach / separation direction force imparting device of the suspension system of the present invention generates an approach / separation direction force such as a damping force by the force of an electromagnetic actuator such as an electromagnetic motor, unlike the so-called hydraulic device of the conventional system. It is supposed to be a structure to let you. Therefore, since the approach / separation direction force can be controlled by controlling the operation of the electromagnetic actuator, the approach / separation direction force can be controlled with good responsiveness and responsiveness. Further, as will be described in detail later, the approaching / separating direction force applying device can function as a damper to effectively absorb unsprung high frequency vibration, and in that case, by controlling the approaching / separating direction force, The degree of vibration absorption effect can be easily controlled, and the function can be sufficiently secured in a situation where the absorber is desired to function effectively. In such a point, the suspension system of the present invention is highly practical. Further, in the suspension system of the present invention, it is desirable to increase the absorber support force (the mutual support force between the absorber and the one member) when the rotation amount of the vehicle body such as the roll amount and the pitch amount is large. The neutral direction force is increased. In addition, the roll behavior, pitch behavior, etc. of the vehicle body may be relatively low in the rotational speed of the vehicle body, so the neutral direction force that does not depend on the speed of fluctuation of the distance between the absorbers (the distance between the absorber and one member) is In the case of suppressing the roll behavior and the pitch behavior, it is suitable as the approaching / separating direction force required for improving the absorber supporting force.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

In addition, if the relationship between each of the following items and claims is shown, the combination of items (1), (2), (7), (15), (16) corresponds to claim 1 However, the limitation of (19) and (22) to claim 1 is added to claim 2, the limitation of (2) to claim 2 is added to claim 3, and claim 1 is added. Any one of claims 3 to 3 with the limitation of item (3) corresponds to claim 4 respectively.

(1) a suspension spring disposed between the unsprung member and the sprung member;
An absorber disposed in parallel with the suspension spring between the unsprung member and the sprung member;
An elastic connection mechanism that elastically connects one member of the unsprung member and the sprung member and the absorber;
In parallel with the elastic coupling mechanism, the one member and the absorber have an electromagnetic actuator and depend on the force generated by the electromagnetic actuator, An approaching / separating direction force applying device that applies an approaching / separating direction force that is a force in the approaching / separating direction to the absorber, and a control device that controls the approaching / separating direction force generated by the approaching / separating direction force applying device. Vehicle suspension system equipped.

  The aspect described in this section can be conceptually illustrated as in FIG. In the embodiment shown in FIG. 1, a suspension spring SS and an absorber A are arranged in parallel with each other between the sprung member Mu and the unsprung member Ml that holds the wheel W. An elastic coupling mechanism CS that elastically couples them to each other is provided between the unsprung member Ml and the approaching and separating of the absorber A and the unsprung member Ml in parallel with the elastic coupling mechanism CS. An approaching / separating direction force applying device D for generating a directional force is provided. The approaching / separating direction force imparting device D is configured to generate an approaching / separating direction force depending on the force of the electromagnetic actuator, and the approaching / separating direction force is controlled by the control device C.

  Hereinafter, with reference to this figure, the “sprung member Mu” in this section means, for example, a portion of the vehicle body supported by the suspension spring SS, and the “unsprung member Ml” In addition, it broadly means components of the vehicle that move up and down with the wheels W, such as suspension arms. The suspension spring only needs to elastically support the unsprung member Ml and the sprung member Mu, and the structure thereof is not particularly limited. For example, various structures such as a coil spring or other elastic member or an air spring using air pressure can be employed.

  The absorber A mainly has a function of generating a damping force with respect to the relative vibration in the vertical direction between the unsprung member Ml and the sprung member Mu, that is, the approach / separation movement between the vehicle body and the wheel W. . The structure is not particularly limited, and for example, a hydraulic type that has been generally employed can be employed. As will be described in detail later, a structure that generates a damping force based on the force of an electromagnetic actuator (which is a concept that includes both an electromagnetic motor and a generator), that is, an electromagnetic absorber (“electromagnetic” It is also possible to adopt a “type actuator”. When adopting this structure, the suspension system is configured as an electromagnetic suspension system (so-called “electromagnetic suspension”). When an electromagnetic absorber is employed, it is possible to generate not only the above-described damping force but also a propulsive force for the relative movement between the unsprung member Ml and the sprung member Mu.

  The elastic coupling mechanism CS is one of the unsprung member Ml and the sprung member Mu (hereinafter sometimes referred to as “one member Mo”. In FIG. 1, the unsprung member Ml is one member Mo). Any structure may be used as long as it can elastically support the absorber A and the structure thereof is not particularly limited. On the other hand, it exhibits an elastic force that maintains a constant distance between the member Mo and the absorber A. It is desirable to adopt a structure that does this. In other words, when the external force is not acting on the suspension system (when the vehicle is stationary on a flat place), the interval is defined as the neutral interval. It is desirable to employ a structure that generates an elastic force in a direction to return the interval to the neutral interval when the distance becomes larger or smaller. Specifically, for example, two elastic members are used, and one of them exhibits an elastic force in a direction to widen the interval between the one member Mo and the absorber A, and the other exhibits an elastic force in a direction to narrow the interval. It is possible to configure the structure such that the distance between the one member Mo and the absorber A is maintained at a neutral distance by balancing the elastic forces. It is also possible to simply adopt an arrangement in which an elastic member such as a coil spring is interposed between the one member Mo and the absorber A, and the relative movement between the one member Mo and the absorber A in the approaching / separating direction is also possible. It is also possible to provide a mechanism for converting into a rotational motion of some kind of rotating body so that an elastic force acts on the rotation of the rotating body.

  The approaching / separating direction force applying device D is arranged in parallel with the elastic coupling mechanism CS, and applies an approaching / separating direction force that is a force in the approaching / separating direction to the member Mo and the absorber A. That is, the force of the direction which makes them approach or separate is exhibited. The approaching / separating direction force is a concept including both a damping force and a propulsive force with respect to a relative motion between the one member Mo and the absorber A. When the damping force is exerted, it functions as a so-called damper. The approaching / separating direction force applying device D in this section is configured to apply the approaching / separating direction force based on the force generated by the electromagnetic actuator. Therefore, by controlling the operation of the electromagnetic actuator, control of the approaching / separating direction force, more specifically, control regarding the magnitude and direction thereof can be executed, and the approaching / separating direction force with excellent responsiveness and responsiveness can be executed. Control becomes possible. The force of the electromagnetic actuator that is the basis of the approaching / separating direction force may be a force using an electromotive force generated when the electromagnetic actuator functions as a generator, or functions as a motor. In some cases, it may be a driving force exerted by electric power supplied from a power source. Further, the electromagnetic actuator may be a linear operation type electromagnetic actuator such as a linear motor, or may be a rotary motion type electromagnetic actuator such as a rotary motor. When a rotary motion type electromagnetic actuator is employed, a motion conversion mechanism is provided for converting the relative motion in the approaching / separating direction between the one member Mo and the absorber A into the rotational motion of the rotating body, and the rotational force is applied to the rotating body. It is also possible to configure so that.

  The control device C can be an electronic control device mainly composed of a computer, for example. Furthermore, for example, when an electromagnetic actuator and a power source are connected via a drive circuit such as an inverter, the control device C issues a control signal to the drive circuit, so that an electromagnetic wave generated by the drive circuit is generated. It is possible to configure so that the operation control of the type actuator is executed.

  In the aspect of this section, the functions of the elastic coupling mechanism CS and the approaching / separating direction force applying device D are not particularly limited. For example, by making the approaching / separating direction force applying device D function as a damper, The specific frequency range transmitted from the unsprung member Ml to the sprung member Mu can be made to function to effectively absorb vibration by the interaction between the coupling mechanism CS and the approaching / separating direction force applying device D. . Specifically, it is possible to effectively absorb unsprung vibrations in the vicinity of the so-called unsprung resonance frequency or higher frequency range, thereby improving the riding comfort of the vehicle. . In that case, if the damping force is controlled so as to change the damping coefficient as a characteristic of the damper, for example, the frequency range of vibration that can be effectively absorbed is changed, the degree of vibration absorption effect, etc. Can be changed. That is, in the suspension system according to the aspect of this section, it is possible to control the target approaching / separating direction force.

  Moreover, in the aspect of this term, the absorber A, the elastic coupling mechanism CS, and the approaching / separating direction force applying device D are connected in series, and a change in the interval between the absorber A and the one member Mo is allowed. Therefore, when the support by the approaching / separating direction force generated by the approaching / separating direction force applying device D is not sufficient, the damping force exerted by the absorber A is effectively applied to the unsprung member Ml and the sprung member Mu. The situation is not granted. This contributes to a decrease in the function of the absorber A, which is the attenuation of the relative motion between the unsprung member Ml and the sprung member Mu. In addition, when the support by the approaching / separating direction force is not sufficient, it becomes a factor that impairs the stability of the posture of the vehicle body. That is, in order to effectively absorb the unsprung high-frequency vibration by the elastic coupling mechanism CS and the approaching / separating direction force applying device D, it is desirable that the damping force by the approaching / separating direction force applying device D is relatively small. On the contrary, when the relative vibration attenuation of the unsprung spring in the relatively low frequency region by the absorber A and the stability of the vehicle body posture are considered, the approach / separation direction force of the approach / separation direction force applying device D causes the absorber to It is desirable to increase the mutual support force between A and the one member Mo (hereinafter sometimes referred to as “absorber support force”), thereby improving the stability of the vehicle body and the riding comfort of the vehicle. In view of such a trade-off phenomenon, as described later, it is desirable to change the approaching / separating direction force according to the situation. In the suspension system according to the aspect of this section, the target approaching / separating direction is desirable. Force changes can be easily performed.

  In the aspect of this section, the purpose of controlling the approaching / separating direction force is not limited to the above purpose. For example, as will be described later, the approaching / separating direction force can be controlled for various purposes, such as a purpose of limiting the range of fluctuation of the distance between the absorber A and the one member Mo.

  (2) The vehicle suspension system according to (1), wherein the absorber has an electromagnetic actuator and is operated by using a force generated by the electromagnetic actuator.

  The aspect described in this section relates to an electromagnetic suspension system. The electromagnetic absorber generates a damping force with respect to the relative motion between the unsprung member Ml and the sprung member Mu, depending on the force generated by an electromagnetic actuator such as an electromagnetic motor. Further, the electromagnetic absorber can exhibit not only a damping force but also a driving force for the relative motion. The electromagnetic absorber has an advantage that a suspension system based on, for example, the skyhook theory can be easily constructed by utilizing characteristics such as good controllability, and is expected to be used in an actual vehicle. When considering the damping force for the relative motion, the relative motion force is large and the stroke of the relative motion needs to be increased to some extent. Therefore, the electromagnetic actuator that the electromagnetic absorber has has a relatively large force. It is desirable to adopt one that exhibits However, such an electromagnetic actuator has a situation that it is difficult to generate an effective damping force by following a relatively high-speed relative motion by inertia or the like. Therefore, the electromagnetic absorber cannot sufficiently absorb relatively high-frequency vibrations. For example, it effectively absorbs vibrations of the unsprung member Ml near or below the unsprung resonance frequency. You will not get. In the aspect of this section, such high-frequency vibration absorption can be borne by the elastic coupling mechanism CS and the approaching / separating direction force applying device D. Therefore, according to the aspect of this section, high-frequency vibration can be absorbed. Thus, an electromagnetic suspension system capable of realizing a vehicle having a good ride comfort can be constructed. As described above, sufficiently effective damping can be achieved by controlling the approach / separation direction force generated by the approach / separation direction force imparting device D even for the unsprung unsprung relative vibration having a relatively low frequency. It is possible to apply a force and to improve the riding comfort with respect to relatively low frequency vibrations.

  (3) The vehicle suspension system according to (1) or (2), wherein the one member is an unsprung member.

  In the aspect of this section, the elastic coupling mechanism CS and the approaching / separating direction force applying device D are disposed between the unsprung member Ml and the absorber A, and they are used for the purpose of absorbing unsprung vibration. The transmission of the unsprung vibration to the absorber A is suppressed. Therefore, for example, in the case of an aspect employing an electromagnetic absorber having an electromagnetic actuator, the suspension system of this aspect is an excellent system from the viewpoint of protection from vibration of the electromagnetic actuator.

  (4) Item (1) to Item (3), wherein the control device controls the approaching / separating direction force having a damping force as a component with respect to the relative movement in the approaching / separating direction between the one member and the absorber. The vehicle suspension system according to any one of the above.

  The aspect of this section is an aspect in which the approaching / separating direction force applying device D exhibits a damping force, in other words, an aspect configured to have a function as a damper. As described above, this is a mode suitable when the high-frequency vibration of the unsprung member Ml is absorbed by the elastic coupling mechanism CS and the approaching / separating direction force applying device D. In addition, the approaching / separating direction force in the aspect of this section may have some component other than the damping force component, or may have only the damping force component.

  (5) The controller is configured to control the approaching / separating direction force including a neutral direction force as a component in a direction in which the distance between the one member and the absorber in the approaching / separating direction is close to the neutral interval. The vehicle suspension system according to any one of items (1) to (4).

  In short, the aspect of this section is an aspect in which the approaching / separating direction force imparting device D exhibits a force in a direction to maintain the distance between the absorber A and the one member Mo at a predetermined distance. The “neutral interval” referred to in this section can be considered as an interval between the absorber A and the one member Mo in a state where the vehicle is stationary on a flat and smooth road surface, for example. Further, the “neutral direction force” referred to in this section is, for example, a force that maintains the distance between the absorber A and the one member Mo (hereinafter sometimes referred to as “the distance between the member absorbers”) as neutral as possible. This means a force or the like that restricts a large deviation from the state, and the mode of this section is an effective mode in the case of executing control that maintains the neutral state and suppresses a large change from the neutral state. For example, when a stopper or the like is provided that restricts the range of fluctuations in the distance between the absorbers, the force in the approaching / separating direction is used for the purpose of suppressing impact, sound generation, etc. due to the function of the stopper. Thus, it is possible to limit the fluctuation of the counter member absorber interval. The approaching / separating direction force in the aspect of this section may have some component other than the neutral direction force component, or may have only the neutral direction force component.

  (6) The control device controls the approaching / separating direction force having as a component the neutral direction force having a magnitude corresponding to a deviation of the interval in the approaching / separating direction between the one member and the absorber from the neutral interval. The vehicle suspension system described in (5) above.

  The mode described in this section is simply a mode in which the neutral direction force is a spring force or a force similar to the spring force. According to the aspect of this section, for example, the approaching / separating direction force applying device D can be used so as to assist the spring force by the elastic coupling mechanism CS.

  (7) The vehicle suspension system according to any one of (1) to (6), wherein the control device includes an approaching / separating direction force change unit that changes the approaching / separating direction force according to a situation.

  The mode of this section is a mode in which the approaching / separating direction force can be changed according to the situation, in other words, based on conditions regarding any state, parameters indicating some state, and the like. In the aspect of this section, the direction, magnitude, etc. of the approaching / separating direction force may be changed, and the direction, magnitude, etc. of some components constituting the approaching / separating direction force may be changed.

  (8) The controller is configured to control the approaching / separating direction force having a damping force as a component with respect to a relative motion in the approaching / separating direction between the one member and the absorber, and the approaching / separating direction force changing unit includes: The vehicle suspension system according to item (7), wherein the damping force is changed.

  The mode described in this section is a mode in which the damping force component of the approaching / separating direction force is changed according to the situation, and in the case where the approaching / separating direction force applying device D described above is functioned as a damper. This is an effective mode. As described above, the absorption effect of unsprung high-frequency vibration can be changed. In addition, the absorber support force can be changed based on the damping force. Incidentally, the absorber support force based on the damping force is a support force having a magnitude that depends on the speed of change in the distance between the member absorbers, so that a particularly large support force can be exhibited when the speed is high. When the approaching / separating direction force is only the damping force component, the mode of this section is a mode of changing the approaching / separating direction force itself.

  (9) The control device is configured to control the approaching / separating direction force having a neutral direction force as a component, which is a force in a direction in which the distance between the one member and the absorber in the approaching / separating direction approaches the neutral interval, The vehicle suspension system according to (7) or (8), wherein the approaching / separating direction changing unit changes the neutral direction force.

  The mode described in this section is a mode in which the neutral direction force component of the approaching / separating direction force is changed according to the situation, and for example, the absorber support force can be changed based on the neutral direction force. By the way, the absorber support force based on the neutral force is different from the absorber support force based on the damping force, and is a support force that does not depend on the speed of change in the distance between the member absorbers. However, a relatively large supporting force can be exhibited. For example, as will be described later, this is effective in a case where a large absorber support force is to be obtained in the case of the roll behavior and pitch behavior of the vehicle body. When the approaching / separating direction force is only the neutral direction force component, the mode of this section is a mode of changing the approaching / separating direction force itself.

  (10) The approaching / separating direction force change unit relates to one or more selected from a vehicle running state, a vehicle operating state, a vehicle attitude state, a vehicle behavior state, and a state of an external force acting on the vehicle. The vehicle suspension system according to any one of items (7) to (9), wherein the approaching / separating direction force is changed according to a situation.

  This section lists the various states that are the basis of the situation on which the approaching / separating direction force change unit relies upon the change of the approaching / separating direction force, in other words, the category to which the basis information for judging the situation belongs. It is. According to the aspect of this section, the approaching / separating direction force can be changed based on the situation based on various states according to the purpose of the change. The “vehicle running state” in this section includes, for example, the vehicle running speed, whether the vehicle is turning or going straight, what road surface the vehicle is running, etc. In the “state that is present”, for example, the operation amount of the accelerator, brake, steering operation member, etc., the operation speed, the state of various operation switches, etc., and in the “vehicle posture state”, for example, the roll amount, pitch amount, The yaw amount is “vehicle behavior state”, for example, roll speed, pitch speed, yaw speed, etc., “external force acting on the vehicle” is, for example, lateral acceleration, vertical acceleration, longitudinal acceleration, etc. , Roll moment, pitch moment and the like are included.

  (11) The vehicle suspension system according to any one of (7) to (10), wherein the approaching / separating direction force changing unit is configured to change the approaching / separating direction force according to a road surface condition.

  The mode described in this section is a mode in which the approaching / separating direction force is changed based on the state of the road surface on which the vehicle is traveling (hereinafter sometimes referred to as “traveling road surface”). Depending on the road surface condition, such as rough road surface, swell road (mogul road), flat road (for example, paved road, etc.), vibrations input to the wheels, the sprung member Mu and the unsprung member Ml Relative vibrations and the like are different. Therefore, the vibration to be absorbed, the way the absorber A functions, etc. differ depending on the road surface condition. According to the aspect described in this section, the characteristics that such a suspension system should have can be arbitrarily changed according to the road surface condition.

(12) The controller is configured to control the approaching / separating direction force having a damping force as a component with respect to the relative movement in the approaching / separating direction between the one member and the absorber, and the approaching / separating direction force changing unit. Is supposed to change its damping force,
The approaching / separating direction force changing unit reduces the damping force in a road surface state where unsprung high frequency vibration is relatively likely to occur, and increases the damping force in a road surface state where unsprung high frequency vibration is relatively difficult to occur. The vehicle suspension system according to item (11).

  The mode described in this section is one mode of changing the approaching / separating direction force according to the road surface condition. For example, when traveling on rough roads, so-called bobble vibrations of around 10 Hz, so-called lumpy vibrations of 15 Hz or more, etc. are generated as unsprung vibrations. The “unsprung high-frequency vibration” referred to in this section can be considered as, for example, such vibration, in other words, vibration in the vicinity of or above the unsprung resonance frequency. In the case where the unsprung high frequency vibration is effectively absorbed and the transmission onto the spring is suppressed, as described above, the approaching / separating direction force applying device D functions as a damper, and the elastic coupling mechanism CS These vibrations can be absorbed by the approaching / separating direction force applying device D. In this case, it is desirable that the approaching / separating direction force, that is, the damping force is relatively small. Conversely, as described above, it is desirable to increase the absorber supporting force against vibrations of several Hz or less, such as tilt vibrations and bouncing vibrations, which are generated not only on rough road surfaces but on many road surfaces. In view of the above, the aspect described in this section is, for example, whether or not the road surface state is relatively easy to generate unsprung high-frequency vibration, that is, whether or not the vehicle is traveling on a rough road surface. The present invention can be implemented as a mode in which the damping force is changed depending on whether or not the probability of traveling on the road surface is high.

  (13) The approaching / separating direction force change unit is configured to change the approaching / separating direction force according to a state of occurrence of unsprung high-frequency vibration, according to any one of (7) to (12) Vehicle suspension system.

  The mode in this section is a mode in which the approaching / separating direction force is changed according to the presence / absence of occurrence of unsprung high-frequency vibration, the probability of occurrence, and the like. This is an aspect deeply related to the aspect changed according to the road surface condition described above, and the description here will be omitted in view of the overlapping description.

  (14) The approaching / separating direction force change unit is configured to change the approaching / separating direction force according to a state of occurrence of relative vibration between the sprung member and the unsprung member. The vehicle suspension system according to any one of the items.

  The mode described in this section is a mode in which the approaching / separating direction force is changed widely corresponding to the vibration input to the suspension system regardless of whether it is unsprung high-frequency vibration. For example, in the case where the approaching / separating direction force imparting device D is functioned as a damper, the above damping is usually performed when a vibration is input that requires a small damping force to increase the support force of the absorber. A mode of changing the force so as to increase is included.

  (15) The vehicle approach according to any one of (7) to (14), wherein the approaching / separating direction force changing unit is configured to change the approaching / separating direction force according to a turning state of a vehicle body. Suspension system.

  The “turning state of the vehicle body” referred to in this section is a state relating to roll, pitch, and yaw behavior, specifically, an amount indicating the degree of the behavior (for example, a turning amount such as a roll amount), and the behavior of the behavior. It means a state related to speed (for example, rotational speed such as roll speed) and force that causes these behaviors (for example, lateral acceleration), and is widely judged from the operation amount, operation speed, etc. of the steering operation member. It also means a turning situation. For example, as described above, in order to suppress the rotational movement of the vehicle body such as the roll of the vehicle body, it is desirable to increase the absorber support force so that the absorber A functions sufficiently. The aspect of this section includes an aspect in which the approaching / separating direction force is changed based on such a viewpoint.

(16) The control device controls the approaching / separating direction force having a neutral direction force as a component in a direction in which the distance between the one member and the absorber in the approaching / separating direction approaches the neutral interval. And the approaching / separating direction changing unit changes the neutral direction force,
The approaching / separating direction force change unit is configured to increase the neutral direction force when the rotation amount of the vehicle body is large and decrease the neutral direction force when the rotation amount of the vehicle body is small. Vehicle suspension system.

  The aspect described in this section is an aspect of an aspect in which the approaching / separating direction force is changed based on the turning state of the vehicle body. In the aspect of this section, as described above, when the rotation amount of the vehicle body such as the roll amount and the pitch amount is large, in view of the desire to increase the absorber support force, the neutral direction force is increased. is doing. In addition, since the rolling behavior and pitch behavior of the vehicle body may be relatively small, the neutral direction force that does not depend on the speed of fluctuation of the member-to-member absorber spacing suppresses the roll behavior and pitch behavior. In this case, the approaching / separating direction force necessary for improving the absorber supporting force is suitable.

  (17) Items (7) to (16), wherein the approaching / separating direction force changing unit changes the approaching / separating direction force according to a situation depending on information received by a car navigation system mounted on the vehicle. The suspension system for a vehicle according to any one of items 1).

  In the mode described in this section, for example, based on information received by a car navigation system (hereinafter sometimes abbreviated as “car navigation”), it is determined what road surface condition the vehicle is currently traveling on. Then, based on the determination, for example, a mode in which the approaching / separating direction force is changed depending on whether the traveling road is a rough road surface or not is included. In this aspect, since preparation for such vibration can be made before the unsprung high frequency vibration is actually input, it is possible to prevent a situation in which the response to the change in the road surface condition is delayed. In such a case, the car navigation system may be configured to receive the information related to the traveling road surface state and directly change the approaching / separating direction force based on the information. The road surface information management system, which is separately provided on the vehicle, receives information on the point, determines the road surface state at the current driving point from the information on the driving point, and changes the approaching / separating direction force based on the determined road surface state It may be configured to. The latter configuration can be considered as a configuration for indirectly changing the approaching / separating direction force based on the car navigation information. In the aspect of this section, the information received by the car navigation system is not limited to the information on the road surface state and the information on the current travel point, but from the information on the various states listed above such as the vehicle travel state. It can be configured to receive some information according to the purpose and change the approaching / separating direction force based on the received information.

  (18) Exceeding limit operation limit in which the control device limits at least one of an approach operation exceeding a set approach limit between the one member and the absorber and a separate operation exceeding a set separation limit by the approach / separation direction force. The vehicle suspension system according to any one of items (1) to (17), which includes a portion.

  The mode described in this section is a mode in which the variation in the distance between the member absorbers described above is limited by using the approaching / separating direction force. For example, this is an effective mode in the case where the variation range of the counter member absorber interval is defined by the stopper mechanism. Specifically, when the distance between the member absorbers is restricted by the stopper, there is a possibility that a phenomenon such as an impact or a sound due to the impact may occur when the stopper is locked. According to the aspect, it becomes possible to prevent or suppress such a phenomenon. The “approach operation” referred to in this section is a so-called bounce operation, and the “separation operation” is a rebound operation. The “setting approach limit” and “setting separation limit” that serve as the restriction criteria are desirably set before the end of the range, for example, so as to have a certain margin for the restriction range by the stopper. Further, it is desirable that the approaching / separating direction force generated at the time of restriction is a force that provides a considerably large resistance to an operation exceeding the limit.

  (19) The vehicle suspension system according to any one of (1) to (18), wherein the electromagnetic actuator included in the approaching / separating direction force applying device functions as a generator.

  When the electromagnetic actuator included in the approaching / separating direction force imparting device functions as a generator, the approaching / separating direction force (hereinafter referred to as “electromotive force”) based on the electromotive force generated by being operated without supplying power from the power source. May be referred to as “approaching and separating direction force depending on electric power”). Therefore, according to the aspect of this section, a suspension system with reduced power consumption is realized. Note that the electromagnetic actuator in this section may function only as a generator, and by causing the electromagnetic motor to function as a generator, an approaching / separating direction force that depends on power supplied from a power source, It is also possible to adopt a configuration in which the approaching / separating direction force depending on the electromotive force is selectively generated. Incidentally, the approaching / separating direction force depending on the electromotive force acts as a damping force.

  The technical features related to the electromagnetic actuators in this section and below are related to the electromagnetic actuators included in the approaching / separating direction force imparting device D. However, the technical features are that the absorber A is an electromagnetic absorber. In the above, it can be a technical feature related to the electromagnetic actuator that the absorber has, and various aspects to which limitations are imposed by these technical features can also be a claimable invention aspect.

  (20) The vehicle suspension system according to (19), wherein the suspension system includes a resistor for causing resistance consumption of the electric power generated by the electromagnetic actuator included in the approaching / separating direction force applying device.

  The mode described in this section is a mode in which the resistor is used as one means for generating the approaching / separating direction force depending on the electromotive force. By making the resistance value of the resistor appropriate, it is possible to make the magnitude of the approaching / separating direction force appropriate.

  (21) The vehicle suspension system according to (20), wherein the control device is configured to control the approaching / separating direction force by changing a resistance value of the resistor.

  The mode described in this section is a mode related to means for controlling the approaching / separating direction force when a resistor is used. According to this section, it is possible to easily change and adjust the approaching / separating direction force.

  (22) The vehicle according to any one of (19) to (21), wherein the suspension system is configured to be able to regenerate power generated by an electromagnetic actuator included in the approaching / separating direction force applying device as a power source. Suspension system.

  The aspect described in this section is an aspect in the case where the approaching / separating direction force depending on the electromotive force is generated. According to the aspect of this section, a suspension system having good power saving characteristics is realized. Specifically, for example, an electromagnetic actuator is connected to a power source via a drive circuit such as an inverter, and the approaching / separating direction force generated by the operation of the drive circuit such as adjustment of the duty ratio in switching of the switching element is adjusted. It is possible to regenerate an amount of electric power corresponding to the magnitude in the power source.

  (23) The control device includes a regenerative / non-regenerative control switching unit that switches between regenerative control that regenerates the generated power and non-regenerative control that does not regenerate the generated power. Vehicle suspension system.

  The mode of this section is a mode of selectively realizing a state where power regeneration to the power source is realized and a state where regeneration is not realized. For example, when the power supply is fully charged, a situation in which regeneration is not possible or undesirable is possible. According to the aspect of this section, it is possible to generate an appropriate approaching / separating direction force depending on the electromotive force regardless of the presence or absence of such a situation.

  (24) The suspension system includes a resistor for resistance-consuming the electromotive force generated in the electromagnetic actuator included in the approaching / separating direction force applying device, and the generated power in the non-regenerative control is resistance The vehicle suspension system according to item (23), wherein the vehicle is configured to cause resistance consumption.

  The mode described in this section is a mode in which the resistor is used when the non-regenerative control is executed in the mode of selectively realizing the regenerative control and the non-regenerative control. In the aspect of this section, for example, as described above, it is possible to generate an appropriate approaching / separating direction force even in non-regenerative control by changing the resistance value.

  Hereinafter, embodiments of the claimable invention will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. can do.

<Configuration of vehicle suspension system>
FIG. 2 is a front sectional view of a vehicle suspension device 12 included in the vehicle suspension system 10 of the present embodiment. The vehicle suspension device 12 is an independent suspension type suspension device and is provided for each of the front, rear, left and right wheels. This suspension device is provided on a suspension lower arm (hereinafter sometimes abbreviated as “lower arm”) 14 that holds a wheel and functions as an unsprung member, and a part of a vehicle body (upper part of a tire housing). An electromagnetic absorber 18 that connects the mount portion 16 that functions as a member is provided. In the present suspension device, a damper device 20 is disposed between the absorber 18 and the lower arm 14, and a coil spring 22 as a suspension spring is disposed between the lower arm 14 and the mount portion 16. Yes.

  The absorber 18 includes an outer tube 30 and an inner tube 32 that is fitted into the outer tube 30 and protrudes downward from the lower end portion of the outer tube 30. A disc-shaped end plate 34 is attached to the lower end portion of the inner tube 32, and this end plate 34 is connected to the lower arm 14 via the damper device 20. On the other hand, the outer tube 30 has an upper end connected to the mount 16.

  The absorber 18 includes a screw rod 40 formed with a male screw, a nut 42 that holds a bearing ball and is screwed with the screw rod 40, and an electromagnetic motor 44 (DC brushless motor) as an electromagnetic actuator. , Simply referred to as “motor 44”). The motor 44 is fixedly accommodated in the motor case 46 and is fixed to the mount portion 16 by fixing the flange portion of the motor case 46 to the upper surface side of the mount portion 16. An upper end portion of the outer tube 30 is fixed to a flange portion of the motor case 46, and the outer tube 30 is connected to the mount portion 16 via the motor case 46. A motor shaft 48 that is a rotation shaft of the motor 44 is integrally connected to the upper end portion of the screw rod 40. That is, the screw rod 40 is arranged in the outer tube 30 in a state where the motor shaft 48 is extended, and is configured to be rotated by the motor 44. On the other hand, the nut 42 is fixed to the upper end portion of the inner tube 32 and is screwed to the screw rod 40 in this state. Furthermore, the outer tube 30 is provided with a pair of guide grooves 50 on the inner wall surface thereof in the direction in which the axis of the absorber 18 extends (hereinafter sometimes referred to as “axial direction”). Each of the pair of keys 52 attached to the outer peripheral upper portion of the nut 42 is fitted. From such a structure, the outer tube 30 and the inner tube 32 are relatively unrotatable and relatively movable in the axial direction.

  With the above structure, the outer tube 30 and the inner tube 32 move relative to each other in the axial direction along with the relative vibration between the vehicle body and the wheels, that is, the relative movement in the vertical direction between the mount portion 16 and the lower arm 14. The screw rod 40 rotates relative to the nut 42. The motor 44 can apply a rotational torque to the screw rod 40. That is, the motor 44 can apply a relative rotational torque to the screw rod 40 and the nut 42, and the relative movement between the mount portion 16 and the lower arm 14 can be achieved by optimizing the direction and magnitude of this torque. On the other hand, it is possible to generate an appropriate resistance force in a direction to prevent the relative movement. This resistance force becomes a damping force for the relative motion. In the present absorber 18, it is also possible to generate a propulsive force with respect to the relative movement between the mount portion 16 and the lower arm 14 by the driving force of the motor 44.

  Next, the damper device 20 will be described with reference to FIG. 3 which is a cross-sectional view taken along the line AA ′ in FIG. 2. The damper device 20 includes a cover tube 70 connected to the lower arm 14 and a right angle to the axis. The cylinder unit 72 and the rack rod 76 are provided so as to intersect with each other. The cover tube 70 has a generally bottomed cylindrical shape including a stepped cylindrical portion and a lid portion that closes the lower end portion of the cylindrical portion, and the rack rod 76 is an end plate 34 attached to the inner tube 32. The rack is formed in the cover tube 70 so as to extend in the axial direction and meshes with a pinion shaft 74 provided in the cylinder unit 72 in a rack formed on the outer peripheral portion.

  The cylinder unit 72 includes a generally cylindrical housing 78 fixed to the cover tube 70, a pinion shaft 74 rotatably held in the housing 78, a torsion bar 80 elastically supporting the pinion shaft 74, an electromagnetic type It has an electromagnetic motor 82 (hereinafter, simply abbreviated as “motor 82”) as an actuator. More specifically, the housing 78 has a first lid portion 84 and a second lid portion 86 that block the both ends of the housing 78, and the pinion shaft 74 has a first lid portion 84 at each of both end portions. The second lid portion 86 is rotatably held via bearings 88 and 90, and meshes with the rack rod 76 at the portion where the pinion is formed. The pinion shaft 74 has a hollow structure in the motor shaft portion, and accommodates a torsion bar 80 therein. One end portion of the torsion bar 80 is fixed to the bottom wall of the motor shaft portion, and the other end portion is fixed to the second lid portion 86. With such a structure, the pinion shaft 74 is elastically supported by the housing 78.

  The motor 82 is configured such that a portion adjacent to the portion where the pinion of the pinion shaft 74 is formed serves as a motor shaft, that is, a rotational operation shaft, and the motor shaft portion (hereinafter referred to as “motor shaft”). And a plurality of stator coils fixedly provided on the inner surface of the peripheral wall of the housing 78 so as to face the permanent magnets 92. 94. The motor 82 is configured as a DC brushless motor in which the permanent magnet 92 functions as a rotor and the stator coil 94 functions as a stator.

  An attachment member 96 is attached to the lower end portion of the cover tube 70, and the damper device 20 is attached to the lower arm 14 by attaching the attachment member 96 to the lower arm 14. An annular guide member 100 is fixed to the upper end portion of the cover tube 70, and the guide member 100 is provided so as to be in contact with the outer peripheral portion of the outer tube 30. The guide member 100 and the outer tube 30 are relatively moved in the axial direction. It is possible. The cover tube 70 is provided with an annular lower retainer 102 on the outer peripheral portion thereof, and a coil as a suspension spring is formed by the lower retainer 102 and an annular upper retainer 104 attached to the lower surface side of the mount portion 16. The spring 22 is supported while being sandwiched. That is, the coil spring 22 and the absorber 18 are disposed in parallel between the lower arm 14 and the mount portion 16.

  A locking pin 106 is inserted into the cover tube 70, and a buffer rubber 108 is attached to the upper surface of the end plate 34 attached to the inner tube 32. A buffer rubber 110 is also attached to the inner bottom wall surface of the cover tube 70. That is, when the absorber 18 and the lower arm 14 are to move in a direction approaching beyond a certain range (hereinafter, referred to as “approaching operation” in some cases), the lower end of the rack rod 76 is interposed via the buffer rubber 110. When it is in contact with the inner bottom wall surface of the cover tube 70 and, conversely, the absorber 18 and the lower arm 14 move in a direction away from a certain range (hereinafter sometimes referred to as “separation operation”), The end plate 34 comes into contact with the locking pin 106 through the buffer rubber 108. That is, in this suspension device, the range of the approaching / separating operation between the absorber 18 and the lower arm 14 is regulated by such a stopper mechanism.

  Further, the cover tube 70 is provided with a rack rod pressing mechanism 112 for reliably engaging the rack rod 76 and the pinion shaft 74. Specifically, the cover tube 70 is provided with a guide tube 114 and a biasing member 116 is disposed in the guide tube 114, and the biasing member 116 is a coil supported by a tube lid 118. The rack rod 76 is biased toward the pinion shaft 74 by the elastic force of the spring 120.

  With the above-described structure, the movement of the rack rod 76 in the axial direction accompanying the approach and separation of the absorber 18 and the lower arm 14 is converted into the rotation of the pinion shaft 74 by the rack and pinion mechanism, and the pinion shaft 74 is torsioned. It is elastically supported by the bar 80. More specifically, the rotation of the pinion shaft 74 is in a state of receiving the elastic force generated by the torsion bar 80. Accordingly, an elastic force is applied to the approaching and separating operation of the absorber 18 and the lower arm 14, and the damper device 20 includes an elastic coupling mechanism that elastically couples the absorber 18 and the lower arm 14. It is composed.

  Further, when the pinion shaft 74 rotates in accordance with the approaching / separating operation between the absorber 18 and the lower arm 14, the motor 82 can apply rotational torque to the pinion shaft 74 that is a motor shaft. That is, by optimizing the direction and magnitude of this torque, it is possible to generate an appropriate resistance force in a direction that prevents the relative movement between the absorber 18 and the lower arm 14. Yes. This resistance force becomes a damping force for the relative motion. In addition, a driving force of the motor 82 can generate a propulsive force with respect to the relative movement between the absorber 18 and the lower arm 14. That is, the damper device 20 relies on the force generated by the motor 82 to apply a force in the approaching / separating direction to the absorber 18 and the lower arm 14 (hereinafter, referred to as “approaching / separating direction force” in some cases). It has a function as a separating direction force imparting device. In other words, the damper device 20 has a structure in which the elastic coupling mechanism and the approaching / separating direction force applying device are arranged in parallel between the lower arm 14 and the absorber 18 as one member.

  FIG. 4 schematically shows the overall configuration of the vehicle suspension system 10 of this embodiment. The present suspension system includes a suspension electronic control device (hereinafter also referred to as “suspension ECU”) 130 that is a control device that executes control of each suspension device 12 provided on each wheel. The suspension ECU 130 is mainly configured by a computer having a CPU, a ROM, a RAM, and the like, and the ROM stores a suspension control program, which will be described later, various data relating to control of the suspension device 12, and the like. . The motor 44 of the absorber 18 is connected to a battery 134 (represented as “INV” and “BAT” in the drawing) via an inverter 132 as a drive circuit. On the other hand, the motor 82 of the damper device 20 has an inverter 138 (shown as “INV” in the figure) connected to the battery 134 via a changeover switch 136 (shown as “CSw” in the figure). The resistor 140 having a variable resistance value is selectively connected to a resistor 140 (indicated as “R” in the drawing). Inverters 132 and 138, a changeover switch 136, and a resistor 140 are connected to the suspension ECU 130, and the suspension ECU 130 controls the force generated by the motor 44 via the inverter 132 and passes through the inverter 138 or the resistor 140. The force generated by the motor 82 is controlled.

As will be described later, the suspension ECU 12 controls the suspension device 12 based on, for example, the road surface condition, the roll state of the vehicle body, and the like. Therefore, in the present suspension system, various sensors for detecting the road surface condition, the roll state of the vehicle body, and the like are provided in various parts of the vehicle, and these various sensors are connected to the suspension ECU 130. Specifically, an unsprung acceleration sensor 142 for detecting the vertical acceleration of the lower arm 14, a steering angle sensor 144 for detecting the steering angle of the steering wheel, and a relative distance between the mount portion 16 and the lower arm 14 are detected. A rotation angle sensor 148 for detecting the rotation angle of the motor 82 of the damper device 20 and a rotation angle sensor 150 for detecting the rotation angle of the motor 44 of the absorber 18 are connected. The battery 134 is provided with a voltage sensor 152 for detecting a voltage, and the voltage sensor 152 is also connected to the suspension ECU 130. Furthermore, a determination mode selection switch 154 for selecting a control mode determination mode of the damper device 20 described later is connected to the suspension ECU 130 according to the suspension characteristics desired by the vehicle operator. Incidentally, these sensors and the like are indicated as “Gs”, “θ”, “St”, “ω ₁ ”, “ω ₂ ”, “V”, and “SSw” in the figure, respectively.

  Further, as will be described later, the suspension device 12 can also execute control according to information received by the car navigation system mounted on the vehicle, specifically, the road surface condition determined based on the current travel point information. Has been. Therefore, the suspension ECU 130 is connected to the road surface information management system 160 via the in-vehicle LAN, and the road surface information management system 160 is connected to the car navigation system (car navigation system) 162 (in the figure, via the in-vehicle LAN). "NAVI" is displayed. The road surface information management system 160 is configured to determine the road surface state of the road at that point with reference to the road surface map data created by learning based on the current travel point information received by the car navigation system 162.

<Control of suspension system>
Control of the suspension apparatus is executed by the suspension ECU 130 as described above. In the present suspension device, the control of the absorber 18 and the control of the damper device 20, more specifically, the operation control of the motor 44 for controlling the force exerted by the absorber 18 (hereinafter sometimes referred to as “absorber force”). And the operation control of the motor 82 for controlling the aforementioned approaching / separating direction force (hereinafter sometimes referred to as “damper force”), which is the force exerted by the portion functioning as the approaching / separating direction force applying device of the damper device 20. And done. The suspension system 10 includes a suspension device 12 on each of the front, rear, left, and right wheels, and these four suspension devices 12 are independently controlled. However, in order to simplify the description, unless otherwise noted, The four suspension devices 12 are handled in a unified manner.

The control of the absorber force is performed for the purpose of generating an appropriate force with respect to the relative motion between the mount portion 16 and the lower arm 14 (hereinafter sometimes referred to as “the relative motion of both members”). Specifically, the stroke sensor 146 detects the relative distance X _A between the mount portion 16 and the lower arm 14, and the suspension ECU 130 calculates the relative speed V _A, which is the change speed, and detects the detected relative distance X _A. Based on the calculated relative velocity V _A , the following formula F _A = C _A · V _A + K _A · X _A
Accordingly, the absorber force F _A is calculated. The first term in the above equation, the absorber force component depends on the relative velocity V _A, that is, a so-called damping force component, C _A is a its gain, which corresponds to a so-called damping coefficient. Further, the second term is the absorber force component depends on the relative distance X _A, a component of the force exerting in the case where the absorber 18 spring manner to function. K _A is a gain related to the component and corresponds to a so-called spring constant.

The main function of the absorber 18 is to attenuate relative vibration between the mount portion 16 and the lower arm 14, more specifically, a relatively low-frequency vibration that can be controlled, that is, a vibration with a relatively large amplitude. Except for the time, the control is performed exclusively so that the absorber force F _A that effectively dampens the vibration is exhibited. Therefore, usually, the gain K _A of the component of the spring force, is a 0, The gain C _A of the damping force component, the effective vibration is set to a value C _A0 is secured . On the other hand, when the vehicle is turning, the absorber force F _A is used as a part of the force for suppressing the roll of the vehicle body. Therefore, when the vehicle turns, the gain K _A for the component is determined to be K _AH in order to exert the spring-like force component. Incidentally, since the roll restraining force is reversed in the direction of the inner turning wheel and the outer turning wheel, the gain K _A for the absorber 18 on the inner turning wheel side and the gain K _A for the absorber 18 on the outer turning wheel side have the same sign. It is determined to be reversed. By adding such a force component, the roll of the vehicle body is effectively suppressed. In summary, as shown in FIG. 5A, the control mode of the absorber 18 is set to “normal mode” and “turning mode”, and whether the vehicle is turning or not. Strictly speaking, one of the control modes is determined depending on whether the steering wheel is operated, and the absorber force F _A is determined based on the gains C _A and K _A set in the determined control mode. The absorber 18 is controlled so that the determined absorber force F _A is exerted.

The operation control of the motor 44 for controlling the absorber force F _A is performed by the inverter 132. Specifically, a control signal for causing the motor 44 to exert the absorber force F _A is output to the inverter 132, and the operation of the motor 44 is controlled by the inverter 132. Specifically, the switching of the switching element of the inverter 132 is based on the rotation angle of the motor 44 so that a pattern corresponding to the direction in which the absorber force F _A is generated, and the magnitude of the absorber force F _A is set. It is performed so as to obtain a corresponding duty ratio. The value detected by the rotation angle sensor 150 is adopted as the rotation angle ω ₂ of the motor 44 that depends on this.

The damper force is controlled for the purpose of generating an appropriate force with respect to the relative movement between the absorber 18 and the lower arm 14. Specifically, the rotation angle ω _{1 of the} motor 82 is detected by the rotation angle sensor 148, and based on the detected rotation angle ω ₁ , the distance between the absorber 18 and the lower arm 14 in the approaching / separating direction (hereinafter referred to as “pair”). Deviation (hereinafter sometimes referred to as “neutral interval”) of the vehicle in a state where the vehicle is stationary on a flat and smooth road surface (hereinafter sometimes referred to as “neutral interval”). L _D is calculated), and the relative speed V _D is calculated based on the calculated interval deviation L _D. Then, based on the distance deviation L _D and the relative speed V _D , the following formula F _D = C _D · V _D + K _D · L _D
Accordingly, the damper force F _D is calculated. Similar to the absorber force F _A , the first term in the above equation is a damper force component that depends on the relative speed V _D , that is, a so-called damping force component, and C _D is its gain and corresponds to a so-called damping coefficient. . Further, the second term is a damper force component that depends on the interval deviation L _D , and in the case where the damper device 20 (strictly, the portion that functions as a relative separating direction force applying device) is made to function as a spring. This is the component of the force exerted, in other words, the damper force component as the neutral direction force described above. K _D is a gain related to the component and corresponds to a so-called spring constant.

The main function of the damper device 20 is absorption of unsprung high-frequency vibrations such as lumpy vibrations that occur when traveling on wasteland. Therefore, when it is desired to fully perform its function, the gain K _D for the damper component as neutral direction force is zero, the gain C _D for the damping force component, a value relatively small damping force is generated It is a certain _CDS . On the other hand, the damper device 20 also has a function of supporting the absorber 18. For example, the damper device 20 may inhibit vibration absorption at a relatively low frequency by the absorber 18, particularly vibration absorption with a large amplitude. There is also the possibility of hindering the stability of the vehicle body posture. Therefore, when it is desired to secure the absorbing function of the low-frequency vibration, to increase the bearing capacity of the absorber 18, the gain C _D for the damping force component and a C _DH is a value comparatively large damping force is obtained Is done. Further, since it is necessary to ensure the roll suppression effect by the absorber 18 when the vehicle turns, the gain C _D is set to C _DH and the neutral force direction is increased in order to increase the damper force component that does not depend on the relative speed V _D. gain K _D for damping force component as a force, a large neutral direction force is determined to K _DH (t) is a value obtained. That is, the damper force F _D, when the rolling amount is the amount of rotation of the vehicle body is increased, is determined as compared with the case the roll amount is small increases, in other words, it is changed in accordance with the vehicle turning status It is. Also. This value K _DH (t) is a function having a time t from the start of turning as a parameter, and gradually increases with the elapse of time t, so that the member-to-member absorber interval gradually approaches the neutral interval. Has been gradually getting bigger. As a result, as long as the turning state continues, the absorber support force becomes larger, and the vehicle body posture is more effectively stabilized.

As in the case of the absorber force F _A , in summary, as shown in FIG. 5B, the control mode of the damper device 20 corresponds to the control mode of the absorber 18 as “normal mode” and “turn mode”. In addition, in the normal mode, the “high frequency vibration absorption mode” suitable for absorbing the unsprung high frequency vibration and the relatively low frequency vibration absorption by the absorber 18 are ensured. Two sub-modes, “low frequency vibration absorption guarantee mode” are set. Similar to the control of the absorber force F _A , the normal mode and the turning mode are determined by whether or not the vehicle is turning. In addition, regarding the determination of the sub mode in the normal mode, two determination modes that can be switched by the driver are prepared, and any of the determination modes is selected by the operation of the determination mode selection switch 154 described above. It depends on what you are doing. Specifically, one of the two determination modes is a mode called a “first determination mode”, which is basically determined in the low-frequency vibration absorption collateral mode, and a road surface state in which unsprung high-frequency vibration is generated. In this case, the high-frequency vibration absorption mode is determined when it can be assumed that the road surface condition has occurred. When this determination mode is selected, a suspension characteristic in which the riding comfort of the vehicle is improved by preferentially absorbing the unsprung high-frequency vibration is obtained. The other is a mode called “second determination mode”, which is basically determined as the high-frequency vibration absorption mode, and is determined as the low-frequency vibration absorption guarantee mode when relatively low-frequency vibration is input. It is an embodiment. When this determination mode is selected, a suspension characteristic in which the ride comfort of the vehicle and the stability of the vehicle body are improved by giving priority to vibration absorption of low-frequency vibrations can be obtained. As described above, in the normal mode, one of the two sub-modes is determined according to the selected determination mode. Regardless of which control mode or sub mode is determined, the damper force F _D is determined based on the gains C _D and K _D set in the determined control mode and sub mode, respectively. as determined damper force F _D is exerted, so that the damper device 20 is controlled.

Furthermore, the damper device 20 has a function of limiting fluctuations in the distance between the member absorbers in order to prevent or alleviate an impact or the like when the above-described stopper mechanism functions. An approach limit is set in the approach operation of the absorber 18 and the lower arm 14, and a separate limit is set in the separate operation, and the damper force F _D is increased or decreased when the interval deviation L _D exceeds or exceeds the set threshold value. Regardless of the above equation, _FDMAX is determined to be the force of the maximum magnitude that can be generated by the motor 82 in a direction that prevents the approaching and separating operations. This determination is made when the control mode is any control mode, and regardless of the determined control mode, the stopper mechanism can prevent or mitigate an impact or the like.

Operation control of the motor 82 for controlling the damper force F _D, except as by the resistor 140 to be described later, is performed by the inverter 138. The operation control by the inverter 138, similarly to the operation control of the motor 44 by the inverter 132, a control signal for exerting a damping force F _D in the motor 82 is outputted to the inverter 138, inverter 138, based on the control signal the motor 82 is controlled. As with the case of the inverter 132, specifically, switching of the switching element included in the inverter 138, based on the rotation angle of the motor 82, so that the pattern corresponding to the generating direction of the damper force F _D, and a damper The duty ratio is set according to the magnitude of the force F _D. The value detected by the rotation angle sensor 148 is adopted as the rotation angle ω ₁ of the motor 82 that depends on this.

<Regeneration of electric power generated by motor>
FIG. 6 conceptually shows the rotational speed-torque characteristics of the motor 82 included in the damper device 20. This figure shows the characteristic when the rotational torque Tq of the motor 82 is exerted in the direction opposite to the rotational direction, that is, the characteristic of the torque with respect to the rotational speed Vω when the braking torque is generated. It is a short-circuit characteristic line shown in this figure, and shows the characteristic when the energization terminals to each phase of the motor 82 are short-circuited with each other, that is, the magnitude of the braking torque obtained when so-called short-circuit braking is performed. It is a characteristic line. The area below the short-circuit characteristic line (shaded area in FIG. 6) is a so-called regenerative braking area, in which the motor 82 functions as a generator and can regenerate electric power generated based on the electromotive force as a power source. This is an area. On the other hand, the region above the short-circuit characteristic line is a so-called reverse braking region, and is a region where the motor 82 receives the supply of electric power from the power source and generates the rotational torque Tq. Motor 82, except when specifically require generation of a large damping force F _D, which is generally a motor so as to operate in the regenerative braking region, in the present suspension system 10, often by a motor 82 The generated power is regenerated in the battery 134.

Operation control of the motor 82 for the regeneration (regeneration control) is performed by the inverter 138, by executing the operation control of the motor 82 in response to the required damping force F _D, damper force F _D is the regenerative braking region In the case where the electric power generated by the battery 134 is regenerated and the reverse braking region is reached, the electric power is supplied from the battery 134 and the magnitude according to the damper force F _D is supplied. Control is performed so as to exhibit the rotational torque Tq. However, when the battery 134 is in a fully charged state, even if it is in the regenerative braking region, further charging is not desirable, so the motor 82 is connected to the resistor 140 by the changeover switch 136, and the motor 82 Control (non-regenerative control) is performed such that the generated power is consumed by the resistor 140.

As schematically shown in FIG. 7, the resistor 140 includes three variable resistors 190 arranged so as to be interposed between the energization terminals of the respective phases of the motor 82, and driving for changing the resistance values of the variable resistors 190. And a circuit 192. Control signals for damping force F _D from the suspension ECU130 is input to the drive circuit 192, drive circuit 192, the resistance value of the variable resistor 190 is changed based on the control signal. Thereby, the motor 82 is controlled so as to generate the rotational torque Tq corresponding to the damper force F _D without depending on the inverter 138.

The motor 44 of the absorber 18 is a motor whose rotational torque corresponding to the required absorber force F _A is generally in the reverse braking region, and almost no power is regenerated. The motor is not provided with a resistor corresponding to 44.

<Suspension control program>
Control of the suspension device 12 is repeated by the suspension ECU 130 with a short time interval (for example, several m to several tens of msec) while the ignition switch is in the ON state, as shown in the flowchart of FIG. Done by being executed. Below, the flow regarding control of the suspension apparatus 12 according to this program is demonstrated in detail, referring the flowchart shown in a figure.

In the control according to the suspension control program, first, in step 1 (hereinafter simply referred to as “S1”; the same applies to other steps), the detection value of the rotation angle sensor 148 provided in the motor 82 provided in the damper device 20. Based on the rotation angle ω ₁ of the motor 82, and in S 2, the relative distance X _A between the mount portion 16 and the lower arm 14 is acquired based on the detection value of the stroke sensor 146. Further, in S 3, steering is performed. Based on the detection value of the angle sensor 144, the steering angle θ of the steering wheel is acquired. Next, in S4, based on the rotation angle omega _1, the distance difference L _D and the relative velocity V _D between the absorber 18 and the lower arm 14 is calculated in S5, based on the relative distance X _A, the relative velocity V _A Is calculated.

  Subsequently, in S6, a road surface condition monitoring subroutine whose flowchart is shown in FIG. 9 is executed. In the road surface condition monitoring subroutine, first, in S31, information regarding the road surface state of the current travel point is acquired from the road surface information management system 160. As described above, the road surface information management system 160 has road surface map data created by learning by itself, and based on the information on the current travel point received by the car navigation system 162, the road surface where the current travel point is rough. It is made to judge whether it is. The road surface at the current travel point simulates a “high-frequency vibration road surface” which is a road surface having a high probability of occurrence of unsprung high-frequency vibration. In S31, the suspension ECU 130 acquires information to that effect from the road surface information management system 160. In subsequent S32, based on the information from the road surface information management system 160, it is determined whether or not the road surface at the current travel point is a high-frequency vibration road surface. When it is determined that the road surface is a high-frequency vibration road surface, the high-frequency vibration flag F, which is a flag used in the subsequent control mode determination, is set to 1 in S33. The high frequency vibration flag F is set to 0.

  In S35, the unsprung acceleration Gs is acquired based on the detection value of the unsprung acceleration sensor 142. In S36, it is determined whether or not the unsprung high frequency vibration is actually generated based on the acquired unsprung acceleration Gs. Is done. In this determination, based on the unsprung acceleration Gs acquired this time and the unsprung acceleration Gs acquired in the execution of this program before this time, when the state of the change satisfies the set condition, It is determined that unsprung high frequency vibration is occurring. Already known algorithms can be used for this determination algorithm, and detailed description thereof is omitted here. This determination result is fed back to the road surface information management system 160 in S37. The road surface information management system 160 updates the road surface map data described above based on the fed back determination result. Next, in S38, it is determined based on the determination result in S36 whether or not unsprung high frequency vibration is occurring. When it is determined that unsprung high frequency vibration is occurring, the high frequency vibration flag F is set to 1 in S39, and when it is determined that high frequency vibration is not occurring, the already determined flag value is maintained. That is, in this subroutine, the high-frequency vibration flag F is set to 1 when the road surface information management system 160 or the determination based on the actual detection of the high-frequency vibration is recognized as the high-frequency vibration road surface. If it is determined that the road surface is not a high-frequency vibration road surface, the high-frequency vibration flag F is set to 0.

After the execution of the road surface condition monitoring subroutine, in S7 of the main routine, it is determined whether or not the vehicle is in a turning state based on whether or not the steering angle θ is greater than or equal to the set threshold angle θ ₀ . When it is determined that the steering angle θ is equal to or larger than the set threshold angle θ _0, it is determined that the vehicle is in a turning state, and in S8, the turning flag G is set to 1, and when it is determined that it is less than the set threshold angle θ ₀ , Assuming that the vehicle is not in the state, the turning flag G is set to 0 in S9.

After the determination of the turning state, an absorber control mode determination subroutine whose flowchart is shown in FIG. 10 is executed in S10. In this subroutine, first, S41.
When the value of the turning flag G is determined and the value of the turning flag G is 1, that is, when turning, in S42, the control mode of the absorber 18 is determined to be the turning mode and is described above. In addition, the gain K _A and the gain C _A are determined as K _AH and C _A0 in the calculation formula for determining the absorber force F _A , respectively. When the value of the turning flag G is 0, that is, when the turning is not in progress, in S43, the control mode is determined as the normal mode, the gain K _A is determined as 0, and the gain C _A is determined as C _A0. The

After the execution of the absorber control mode determination subroutine in S10, the damper device control mode determination subroutine shown in the flowchart of FIG. 11 is executed in S11. In this subroutine, first, in S51, the interval deviation L _D is less than the set approach limit threshold α or larger than the set separation limit threshold β, and the absolute value of the interval deviation L _D is acquired in the execution of this program before this time. It is determined whether the interval deviation L _DP is greater than the absolute value. If the above condition is satisfied, approaching the limit, approach operation beyond the separation limit, separation operation has been made, in S52, when it is determined by the processing after the damper force F _D is, approximately the highest [F _D = F _DMAX ] is selected as the calculation formula of the damper force F _D so as to be determined by the above-described F _DMAX that is the damper force. When the condition of S51 is not satisfied, the above-mentioned [F _D = C _D · V _D + K _D · L _D ] is selected as the calculation formula of the damper force F _{D in} S53.

Next, in S54, the value of the turning flag G is determined. If the value of the turning flag G is 1, that is, if turning, the control mode of the damper device 20 is determined to be the turning mode in S55. Then, the gain K _D in the latter arithmetic expression is determined as K _DH (t), and the gain C _D is determined as C _DH . Note that K _DH (t) is determined with reference to map data whose parameter is elapsed time t after the start of turning, but K _DH (t) increases as time elapses. Yes. Therefore, a counter-up process for grasping the passage of time is executed in the next S56.

When the value of the turning flag G is 0, that is, when not turning, the control mode of the damper device 20 is set to the normal mode. In that case, first, in S57, the elapsed time t from the start of turning is reset. Next, in order to determine the sub-mode, in S58, it is determined which one of the first determination mode and the second determination mode is selected by the determination mode selection switch 154. When the first determination mode is selected, the value of the high-frequency vibration flag F determined in the road surface condition monitoring subroutine of S6 is determined in S59. If the high-frequency vibration flag is 1, the sub-mode is determined to be the high-frequency vibration absorption mode in S60, and the gain C _D and the gain K _D in the above arithmetic expression are determined to be C _DS and 0, respectively. If the high frequency vibration flag F is 0, at S61, the sub-mode is determined in the low-frequency vibration absorbing collateral mode, the gain C _D is the C _DH in the arithmetic expression, to gain K _D of 0, respectively, are determined . On the other hand, when the second determination mode is selected, in S62, based on the detection values of the current and previous stroke sensors 146, a relatively low frequency and a relatively large amplitude according to a predetermined determination condition. It is determined whether or not the relative vibration on the large unsprung spring is input. In such cases the low frequency vibration is determined to have been input, at S61, the sub-mode is determined in the low-frequency vibration absorbing collateral mode, the gain C _D is the C _DH in the computing equation, the gain K _D Are each determined to be 0. If it is determined that such low-frequency vibration is not input, the sub-mode is determined to be the high-frequency vibration absorption mode in S60, the gain C _D in the above equation is C _DS , and the gain K _D is 0. Respectively.

After the damper device control mode determination subroutine is executed, in S12, the absorber force F _A is already determined by the gain K _A, C _A is calculated according to the arithmetic expression which is determined, in S13, the decision _A signal corresponding to the absorbed absorber force F _A is sent to the inverter 132. With this process, the motor 44 of the absorber 18 is controlled to exhibit the determined absorber force F _A.

Next, in S14, the damper force F _D is determined by being calculated according to the selected arithmetic expression or the arithmetic expression that has been selected and the gains K _D and C _D have already been determined. Subsequently, in S15, the rotational torque Tq of the motor 82 for exhibiting the determined damping force F _D, the relationship between the rotational speed Vω of the motor 82 which is calculated previously from motor 82 rotation angle omega ₁ that is acquired However, it is determined whether or not it is in the regenerative braking region while referring to the map data as shown in FIG. If it is determined that the regenerative braking region, in S16, the voltage whether E is less than or setting the threshold voltage E ₀ of the battery 134 detected by voltage sensor 152 is determined. If it is determined that the voltage E of the battery 134 is less than the set threshold voltage E ₀ , or if it is determined that the voltage is not in the regenerative braking region in S15, the changeover switch 136 causes the motor 82 and the inverter 138 in S17. And are actuated to be connected. Further, when the voltage E of the battery 134 is determined to be set threshold voltage E ₀ or more in S16, in S18, the change-over switch 136 is operated such that the motor 82 and the resistor 140 is connected . After the motor 82 is connected to one of the inverter 138 and the resistor 140, in S19, a signal corresponding to the damping force F _D determined above is sent to the in-inverter 138 or resistor 140. This process, motor 82 included in the damper device 20 is operated controlled to exert the determined damping force F _D. The process of S19 is completed, and one execution of this program ends.

<Functional configuration of control device>
The suspension ECU 130 that executes the program as described above can be considered to have a functional configuration as shown in FIG. 12 based on the execution process. According to the functional configuration, the suspension ECU 130 has the absorber force determining unit 200 that determines the absorber force F _A exhibited by the absorber 18, and the damper that determines the damper force F _D exhibited by the damper device 20. The force determining unit 202 is included.

According to the above program, the absorber force F _A is changed according to the turning state as a result of the control mode being determined according to the turning state by the processing of the absorber control mode determining subroutine. . That is, the absorber force determination unit 200 includes the absorber force change unit 204 as a functional unit that functions by executing the processing of the subroutine.

On the other hand, the damper force F _D, by an arithmetic expression used for the determination by the processing of S51~S53 of the damper device control mode decision subroutine is selected, approaching the limit, beyond the separating limits approaching operation, the separating operation is performed As a result, it becomes a force that restricts the operation in that case. Therefore, the damper force determining unit 202 includes the limit excess operation limiting unit 206 as a functional unit that functions by executing these processes. Further, the damper force F _D is the vehicle turning status by treatment S54～S62, by road surface condition, the control mode according to the input status of the vibration is determined and consequently changed depending on their situation It has become a thing. That is, the damper force determining unit 202 has a damper force changing unit 208 (which is one mode of the approaching / separating direction force changing unit) as a functional unit that functions when these processes are executed.

  Further, according to the above program, when the motor 82 provided in the damper device 20 performs power generation based on the electromotive force in the processes of S15 to S19, the control is switched between regenerative power generation and non-regenerative control. . Therefore, the suspension ECU 130 has a regenerative / non-regenerative control switching unit 210 as a functional unit that functions by executing these processes.

1 is a diagram conceptually illustrating a suspension device employed in a vehicle suspension system according to a claimable invention. It is front sectional drawing of the suspension apparatus employ | adopted as the suspension system for vehicles which is an Example of claimable invention. FIG. 3 is a cross-sectional view taken along line AA ′ of the suspension device shown in FIG. 2. 1 is a schematic diagram illustrating an overall configuration of a vehicle suspension system according to an embodiment. 3 is a table showing control modes of an absorber and a damper device constituting the suspension device shown in FIG. 2 and gains for each control mode in an arithmetic expression employed for determining the absorber force and the damper force. It is a chart which shows the characteristic of the electromagnetic motor which the damper apparatus 20 which comprises the suspension apparatus of FIG. 2 has. It is a figure which shows notionally the structure of the resistor with which the suspension for vehicles of an Example is provided. It is a flowchart which shows the suspension control program performed in control of the suspension system for vehicles of an Example. It is a flowchart which shows the road surface condition monitoring subroutine performed in a suspension control program. It is a flowchart which shows the absorber control mode determination subroutine performed in a suspension control program. It is a flowchart which shows the damper apparatus control mode determination subroutine performed in a suspension control program. It is a block diagram regarding the function of the suspension electronic control apparatus which manages control of the suspension system for vehicles of an Example.

Explanation of symbols

10: Suspension system for vehicle 14: Suspension lower arm (unsprung member) 16: Mount part (sprung member) 18: Absorber 20: Damper device (elastic coupling mechanism) (applying / separating direction force applying device) 22: Coil spring (suspension) 44): Electromagnetic motor 82: Electromagnetic motor 130: Suspension electronic control device 132, 138: Inverter 140: Resistor 160: Road surface information management system 162: Car navigation system 200: Absorber force determination unit 202: Damper force determination unit 204: Absorber force changing unit 206: Excess limit operation limiting unit 208: Damper force changing unit (approaching / separating direction force changing unit) 210: Regenerative / non-regenerative control switching unit

Claims (4)

A suspension spring disposed between the unsprung member and the sprung member;
The electromagnetic spring is disposed in parallel with the suspension spring between the unsprung member and the sprung member, and has an electromagnetic actuator and operates using the force generated by the electromagnetic actuator. With an absorber,
An elastic connection mechanism that elastically connects one member of the unsprung member and the sprung member and the absorber;
In parallel with the elastic coupling mechanism, the one member and the absorber have an electromagnetic actuator and depend on the force generated by the electromagnetic actuator, An approaching / separating direction force applying device that applies an approaching / separating direction force that is a force in the approaching / separating direction to the absorber, and a control device that controls the approaching / separating direction force generated by the approaching / separating direction force applying device. A vehicle suspension system comprising :
The control device is
While controlling the approaching / separating direction force having a neutral direction force as a component in a direction in which the interval in the approaching / separating direction between the one member and the absorber approaches the neutral interval,
An approaching / separating direction force changing unit that changes the approaching / separating direction force so as to increase the neutral direction force when the vehicle body rotation amount is large and to decrease the neutral direction force when the vehicle body rotation amount is small; A suspension system for a vehicle. Is intended to electromagnetic actuating device with said vehicle distance direction force imparting device functions as a generator, the suspension system, in claim 1, electric power is regenerated configured to be able to supply the its electromagnetic actuation device is power The vehicle suspension system described. The vehicle suspension system according to claim 2 , wherein the control device includes a regenerative / non-regenerative control switching unit that switches between regenerative control that regenerates the generated power and non-regenerative control that does not regenerate the generated power. . The vehicle suspension system according to any one of claims 1 to 3, wherein the one member is an unsprung member.

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