JP3414140B2 - Vehicle suspension device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device for a vehicle that regulates or controls the vertical movement of a sprung member with respect to an unsprung member by utilizing an electromagnetic force generated by a magnet and an exciting coil.

[0002]

2. Description of the Related Art Conventionally, an apparatus of this type is disclosed in, for example, Japanese Patent Laid-Open No.
As disclosed in JP-A-44758, a coil is arranged between an outer cylinder and an inner cylinder that form a damper device, and the outer peripheral surface of a piston in the inner cylinder and the outer cylinder that form the damper device are arranged. A permanent magnet is arranged on the outer peripheral surface so as to face the coil,
By controlling the energization of the coil, the vehicle height is adjusted and a damping force is applied to the vertical vibration of the unsprung member with respect to the sprung member.

[0003]

However, in the above-mentioned conventional apparatus, since the magnet and the coil are arranged inside the outer cylinder, that is, in the working fluid, the friction powder in the working fluid adheres to the magnet. As a result, the outer peripheral surface of the magnet and the inner peripheral surface of the inner cylinder are abraded, or the characteristics of the electromagnetic force change due to the temperature rise of the hydraulic fluid. Further, since the magnet is also arranged outside the outer cylinder and the outside is exposed to the outside air, iron powder and other powder from the outside adhere to the magnet, and the inner peripheral surface of the magnet and the outer The outer peripheral surface of the cylinder becomes worn. Further, since the magnetic force lines pass through the inner cylinder and the outer cylinder, both cylinders need to be made of a non-magnetic material and also need some strength, which increases the material cost of both cylinders.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to address the above problems, and is intended to provide a low-cost, high-quality suspension device.

[0005] order to achieve this object, the present invention has a piston rod which is movable forward and backward protruded from the upper end surface of the encapsulated cylinder and the cylinder hydraulic fluid, the lower end of the cylinder to the unsprung member A damper device for assembling and assembling the upper end of the piston rod to the sprung member to generate a damping force by the vertical movement of the sprung member with respect to the unsprung member, and the lower end provided on the outer peripheral surfaces of the cylinder and the piston rod. Is supported on the outer peripheral surface of the cylinder and has a flexible case whose upper end is supported by the sprung member, and the upper and lower parts of the sprung member with respect to the unsprung member are enclosed by the gas enclosed in the case. A suspension device for a vehicle, comprising an air spring device for imparting a spring action to movement, which is inside the case.
Te, before Symbol provided a cylindrical magnet and a coil which is displaced integrally respectively with said cylinder and said piston rod while being opposed to each other outside of the cylinder, the magnet is
A cylindrical non-magnetic material supported on the outer circumference of the cylinder
Molded intended to provide a suspension device for a vehicle according to JP <br/> Features of which is fixed on the outer peripheral surface of the support member Oh <br/> Ru.

Suspension device configured as described above
In the above, since both the magnet and the coil are arranged outside the cylinder and in the air which is shielded from the outside, the problem of the arrangement in the working fluid in the above-mentioned conventional device is also exposed to the outside air. Problems are also solved, and both quality and durability are improved. Further, since the necessary magnetic lines of force do not pass through the cylinder, the cylinder can be manufactured from a low-cost material such as iron. Furthermore, the air in the air spring device is usually air that has passed through devices such as an air filter and a dryer.
Since the environmental conditions in which the magnet and the coil are arranged are also good, the characteristics of the magnet and the coil are always kept good, and the durability is also improved.

Another structural feature of the present invention is that the case is attached to an upper end portion of a piston rod of the damper device.
The upper end of the sprung member is assembled airtightly and elastically attached to the sprung member.
A circle supported by and surrounding the piston rod
A cylindrical upper case and a cylinder that constitutes the damper device.
Cylinder with its lower end airtightly assembled to the outer peripheral surface of the cylinder
And a lower case cylindrical, which is arranged to surround the upper
Airtightly connect one end to the bottom of the case and the other end to the front.
Serial constituted by the coupling case flexible and hermetically connected to the outer peripheral surface of the lower case, supporting the magnets or excitation coil
Assemble a cylindrical supporting member to the upper case of the lower case
There is something wrong .

According to this, even if the inclination of the cylinder with respect to the sprung member changes, the piston rod also tilts together with the cylinder, the upper case interlocks with the piston rod, and the lower case interlocks with the cylinder to integrally tilt. Therefore, the distance between the magnet and the coil fixed to the upper case and the lower case, respectively, is always kept constant, and the characteristic of the magnetic force generated by the magnet and the coil is always kept constant.

[0009]

Further, in one embodiment of the present invention,
It has a cylinder filled with hydraulic fluid and a piston rod protruding from the upper end surface of the cylinder so as to be able to move forward and backward, and the lower end of the cylinder is assembled to the unsprung member and the upper end of the piston rod is assembled to the sprung member. A damper device that generates a damping force by vertical movement of an unsprung member with respect to an unsprung member; An air spring device having a flexible case supported by the upper member, and providing a spring action for vertical movement of the sprung member with respect to the unsprung member by the gas enclosed in the case. In the suspension device for a vehicle, the cylinder is disposed inside the case and outside the cylinder so as to face each other. And a cylindrical magnet and a coil that displace integrally with the piston rod, respectively, and the case is formed in a cylindrical shape and an upper case having an upper surface supported by the sprung member, and a cylindrical shape. And a lower case whose lower end is fixed to the outer peripheral surface of the cylinder, and a connecting case which is made of a material that is easily deformable and is formed into a sheet shape to connect the upper case and the lower case. A cylindrical support member is provided separately from the cylinder, one of the magnet and the coil is fixed to the inner peripheral surface of the upper case, and the other of the magnet and the coil is the outer periphery of the support member. Fixed to the surface,
A suspension device for a vehicle is provided, in which a radial through hole is provided in the support member so as to open to a surface where the magnet and the coil face each other.

In this embodiment, even if the opposing surfaces of the magnet and the exciting coil are brought close to each other, the air flow flowing in the case of the air spring device is generated when the sprung member vibrates with respect to the unsprung member. It comes to flow between the facing surfaces through the through holes. Therefore, even if the magnet surface and the coil surface stick to each other due to the difference in inclination between the upper case and the lower case,
Since they are separated by the air flow, the distance between the magnet and the coil can be reduced and a large magnetic force can be obtained.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway view showing an entire suspension system for a vehicle, and FIG. 2 is an enlarged view of a central portion of the drawing. Is shown. This suspension device includes a damper device arranged between a vehicle body BD as a sprung member and a lower arm LA as an unsprung member, and an air spring device provided on the outer circumference of the damper device.

The damper device includes an outer cylinder 11 and an inner cylinder 12 arranged coaxially, and both cylinders 1.
1 and 12, and a piston rod 13 assembled so as to be movable back and forth in the axial direction. The outer cylinder 11 is assembled at its lower end to the lower arm LA via a bush (not shown). The inner cylinder 12 includes an outer cylinder 11 at an upper end thereof via an annular support plate 14.
Is liquid-tightly supported on the upper inner peripheral surface of the outer cylinder 11, and is supported at its lower end on the lower inner peripheral surface of the outer cylinder 11 via a supporting member (not shown). The piston rod 13 extends upward from the outer cylinder 11, and is attached to the vehicle body BD at its upper end via an upper support 16 fixed to the vehicle body BD by screws 15 and 15.
The upper support 16 contains an elastic material such as rubber and allows a slight change in the inclination of the piston rod 13 with respect to the vehicle body BD.

The inner cylinder 12 is divided into upper and lower chambers R1 and R2 by a main piston 17 which is fixed to the outer peripheral surface of the piston rod 13 and slides axially in a liquid-tight manner on the inner peripheral surface of the inner cylinder 12. ing. Upper and lower chambers R1, R
2 is filled with hydraulic fluid (hydraulic oil), and the lower chamber R2 communicates with the annular chamber R3 formed between the outer cylinder 11 and the inner cylinder 12 at the lower end of the inner cylinder 12. Gas is also enclosed in the annular chamber R3,
3 is an inner cylinder 1 as the piston rod 13 moves back and forth
The volume change of the hydraulic fluid in the two upper and lower chambers R1 and R2 is absorbed.

Upper and lower chambers R1 and R2 are provided in the main piston 17.
A fixed orifice (not shown in the figure) that connects the pistons 13 to each other is provided, and the orifice generates a damping force as the piston rod 13 moves up and down. A sub-piston 18 is fixed to the outer peripheral surface of the piston rod 13 below the main piston 17 with some clearance between the sub-piston 18 and the inner peripheral surface of the inner cylinder 12. Sub piston 18
A variable orifice (not shown), which connects the upper and lower chambers R1 and R2 to each other, is provided therein, and the opening of the variable orifice is switched by a damping force switching actuator 21 provided at the upper end of the piston rod 13. It is designed to be used. A valve member (not shown) for adjusting the opening of the variable orifice is driven by the actuator 21 via a connecting mechanism provided in the piston rod 13. A rebound stopper 22 is assembled above the main piston 17 and on the outer circumference of the piston rod 13, and the stopper 22 causes the upward displacement of the piston rod 13 associated with the rebound of the vehicle body BD with the support plate 14. It is elastically regulated by the contact.

The air spring device has a cylindrical upper case 23.
And a lower case 24, and a connecting case 25 that hermetically connects the two cases 23, 24 together.
~ 25 outer cylinder 11 and piston rod 1
An air chamber R4 is formed on the outer periphery of the air conditioner 3. This air chamber R
An electrically controlled intake and exhaust device (not shown) is connected to 4 to adjust the amount of air in the same room R4.

The upper case 23 is formed of a flexible resin, and is supported on the vehicle body BD via the upper support 26 and the support plate 27 on its upper surface, and the piston rod 13 is supported via the support plate 27. Is hermetically fixed on the outer peripheral surface of the upper end of the. The upper support 26 has a built-in elastic material such as rubber, and allows a slight change in the inclination of the upper case 23 with respect to the vehicle body BD. A bounce stopper 28 made of rubber is attached to the lower surface of the support plate 27. The stopper 28 abuts an annular stopper plate 31 fixed to the upper surface of the outer cylinder 11 to elastically bounce the vehicle body BD. regulate. The lower case 24 is also formed of resin, and is hermetically fixed on the outer peripheral surface of the cylindrical member 32 welded and fixed to the outer peripheral surface of the outer cylinder 11 on the lower inner peripheral surface thereof. The connecting case 25 is composed of a diaphragm mainly made of rubber having a high elasticity, and the upper end thereof is airtightly fixed to the outer peripheral surface of the lower end portion of the upper case 23 by a caulking ring 33 and the lower end portion thereof. A caulking ring 34 is airtightly fixed to the upper outer peripheral surface of the lower case 24.

A support member 35 formed of a non-magnetic material in a cylindrical shape is erected and fixed on the upper end surface of the lower case 24.
An annular magnet (permanent magnet) 3 is provided on the outer peripheral surface of the member 35.
6, 37 are fixed. The lower end surface of the magnet 36 and the upper end surface of the magnet 37 are connected to one of the magnetic poles (for example, S pole).
Of the other magnetic pole (for example, N
Magnetized to the pole. An annular rib 38 is fixed on the inner peripheral surface of the upper end portion of the support member 35, and the rib 38 is in contact with the outer peripheral surface of the stopper plate 31 on the inner peripheral surface thereof, so that the support member 35 is outside. The cylinder 11 is supported separately on the outer peripheral surface of the upper end portion. Also,
Holes 38a that communicate with each other in the vertical direction are provided at a plurality of appropriate positions in the circumferential direction of the rib 38, and communicate with the chambers above and below the stopper plate 31.

On the outer peripheral surfaces of these magnets 36 and 37,
A cylindrical exciting coil assembly is provided facing the magnets 36 and 37. This excitation coil assembly has a cylindrical casing 41 made of resin. On the inner peripheral surface of the casing 41, a plurality of coils 42 (C1 to C15) whose axial direction is the extending direction of the piston rod 13
Are arranged at equal intervals along the axial direction via resin spacers 43. Coil 42 is lead wire 4
It is guided to the outside of the upper case 23 via 2a. A coating layer 44 coated with a slippery resin such as Teflon is provided on the inner peripheral surface of the spacer 43. The layer 44 is a coating layer coated with the same resin on the outer peripheral surfaces of the upper ends of the lower case 24 and the support member 35. In cooperation with 45 and 46,
Even if the coating layer 44 and the coating layers 45 and 46 contact each other, the frictional force is reduced. The ribs 47 are provided on the inner peripheral surface of the upper case 23 at appropriate positions in the circumferential direction.
Is provided to support the casing 41 on the inner peripheral surface of the upper case 23 at an appropriate position.

The coil assembly composed of the casing 41, the coil 42 and the spacer 43 having the above structure is
When the caulking ring 33 crimps the connecting case 25 to the upper case 23, the rubber sheet 4 formed into a cylindrical shape is crimped.
It is fixed on the inner peripheral surface of the upper case 23 via 8. In this case, even if the upper case 23 and the casing 41 creep to some extent, the coil assembly is fixed to the inner peripheral surface of the upper casing 23 firmly and with good durability due to the elasticity of the rubber sheet 48.

Next, the electric control device for controlling the suspension device constructed as described above will be explained. FIG. 3 shows the whole electric control device in a block diagram.

This electric control device includes a steering angle sensor 51, a vehicle height sensor 52, a lateral acceleration sensor 53 and a vehicle speed sensor 54.
Is equipped with. The steering angle sensor 51 detects the rotation angle of a steering wheel (not shown) as the steering wheel angle θf,
A detection signal indicating the steering wheel steering angle θf is output. The vehicle height sensor 52 is provided between the vehicle body BD and the lower arm LA, and measures the height of the vehicle body BD with respect to the lower arm LA by the vehicle height HT.
And outputs a detection signal indicating the vehicle height HT. The lateral acceleration sensor 53 is attached to the vehicle body BD, detects lateral acceleration of the vehicle body BD as lateral acceleration Gy, and outputs a detection signal representing the lateral acceleration Gy. The vehicle speed sensor 54 detects the vehicle speed V and outputs a detection signal indicating the vehicle speed V.

Each of these sensors 51 to 54 is connected to a microcomputer 55. The microcomputer 55 controls a suspension device by executing a program to be described later to control the vehicle height and the damping force. The microcomputer 55 includes a drive circuit 56 for controlling the vehicle height and a drive circuit 57 for switching the damping force.
A drive circuit 58 for energizing the coil 42 and the coil 42 is connected to each. The drive circuit 56 is a vehicle height control actuator 6 provided in an intake and exhaust device (not shown) for controlling supply and discharge of air to and from the air chamber R4.
0 is drive-controlled. The drive circuit 57 drives and controls the actuator 21 for switching the damping force.

The drive circuit 58 controls the energization and de-energization of a plurality of coils 42, and as shown in FIG. 4, each coil 42 (denoted by C1 to C15 from top to bottom).
On the other hand, each of them is composed of four transistors Tr1 to Tr4. The transistors Tr1 and Tr2 are of PNP type, the transistors Tr3 and Tr4 are of NPN type, and are connected in series between the power source + V and the ground, and each coil is connected to each connection point of the transistors Tr1, Tr3 and Tr2, Tr4. Four
Both ends of 2 are connected. In this case, by applying a control voltage to the transistors Tr1 and Tr4 and turning on both the transistors Tr1 and Tr4 at the same time, a current flows in the direction indicated by the solid line in the figure, and the magnetic flux passes through the coil 42 from below to above (of the coil 42). (Equivalent to a magnet magnetized with the north pole at the top and the south pole at the bottom). On the other hand, when a control voltage is applied to the transistors Tr2 and Tr3 and both transistors Tr2 and Tr3 are turned on at the same time, a current flows in the direction of the broken line arrow in the figure, and the magnetic flux passes through the coil 42 from top to bottom (coil 4
The upper part of 2 is equivalent to a magnet magnetized to the south pole and the lower part to the north pole). Hereinafter, the former energized state is referred to as forward energization, and the latter energized state is referred to as reverse energization.

Next, the operation of the suspension device configured as described above will be described in the order of vehicle height adjustment, damping force switching, and energization / de-energization control of the coil 42.

The vehicle height adjustment is performed by executing a vehicle height adjustment program (not shown). Microcomputer 55
Executes the vehicle height adjustment program every predetermined short time, determines whether the vehicle height HT input from the vehicle height sensor 52 is higher or lower than a predetermined reference vehicle height, and the determination result is the same. Based on the above, the vehicle height control actuator 60 is controlled via the drive circuit 56. If the detected vehicle height HT is higher than the reference vehicle height, the vehicle height control actuator 60 discharges the air in the air chamber R4 of the air spring device. Due to this exhaust, the air pressure in the air chamber R4 is lowered, the upper case 23 and the piston rod 13 are lowered, and the vehicle body BD is also lowered.
On the other hand, if the detected vehicle height HT is lower than the reference vehicle height, the vehicle height control actuator 60 supplies air into the air chamber R4 of the air spring device. Due to this air supply, the air pressure in the air chamber R4 rises, and the upper case 23 and the piston rod 13
Rises and the body BD also rises. As a result, the height of the vehicle body BD with respect to the lower arm LA is always kept substantially constant.

On the other hand, even if an external force is applied to the vehicle body BD from the road surface, the air spring device that fills the air chamber R4 with air absorbs the applied external force and softens the impact on the vehicle body BD. The ride quality of the vehicle is improved.

Next, the damping force switching control will be described. This control is performed by executing the damping force switching program including steps 100 to 120 in FIG.
The microcomputer 55 repeatedly executes this program for each predetermined short time, and after starting at step 100, at step 102, the detection signals representing the vehicle speed V and the lateral acceleration Gy are respectively output from the vehicle speed sensor 54 and the lateral acceleration sensor 53. By inputting and referring to the V-Gy map built in the computer 55 through the processing of steps 104 to 118, the driving of the damping force switching actuator 21 is controlled according to the vehicle speed V and the lateral acceleration Gy. V-Gy
As shown in FIG. 6, the map shows two characteristic curves L1 and L2 in which the lateral acceleration Gy decreases as the vehicle speed V increases.
Is stored.

When the coordinate point determined by the vehicle speed V and the lateral acceleration Gy is in the upper region of the characteristic curve L1 shown in FIG. 6, the microcomputer 55 executes the processing of steps 104 to 108 so that the damper device is in the soft state (first flag). On condition that FLG1 is “0”), the drive circuit 56
The actuator 21 is controlled to be switched to the hardware side via. The actuator 21 drives the valve member in the sub-piston 18 to set the opening degree of the variable orifice small, and switches the damper device to the hard state. The hard state of the damper device is maintained until the coordinate point determined by the vehicle speed V and the lateral acceleration Gy is in the lower region of the characteristic curve L2 in FIG. When the coordinate point determined by the vehicle speed V and the lateral acceleration Gy is in the lower region of the characteristic curve L2 in FIG. 6,
The microcomputer 55 executes steps 112 to 118.
By the processing of (1), the actuator 21 is switched to the soft side via the drive circuit 56 under the condition that the damper device is in the hard state (the first flag FLG1 is "1"). The actuator 21 drives the valve member in the sub-piston 18 to set a large opening of the variable orifice, and switches the damper device to the soft state. The soft state of the damper device is maintained until the coordinate point determined by the vehicle speed V and the lateral acceleration Gy is in the upper region of the characteristic curve L1 in FIG. 6 (see FIG. 9).

By the damping force switching control as described above, the damping force of the damper device is selectively switched between software and hardware according to the running state of the vehicle. Therefore,
Due to input from the road surface and changes in the posture of the body BD, the body BD
Even if the vehicle vibrates up and down, the vibration is suppressed by the damping force of the damper device according to the running state of the vehicle. Specifically, when the vehicle speed V and the lateral acceleration Gy are small, the damping force is kept small, so that the riding comfort of the vehicle is emphasized. on the other hand,
When the vehicle speed V or the lateral acceleration Gy is large, the damping force is kept large, so that the posture change of the vehicle at the time of a sharp turn or the like is suppressed, and the stability of the vehicle is improved.

Next, the energization / de-energization control of the coil 42 will be described. This control is performed from step 130 of FIG.
This is performed by executing the energization / non-energization control program consisting of 152. The microcomputer 55 repeatedly executes this program every predetermined short time,
After the start of 0, in step 132, the detection signals representing the steering wheel steering angle θf and the vehicle height HT are respectively input from the steering angle sensor 51 and the vehicle height sensor 52, and the detected steering wheel steering angle θf is time differentiated in step 134. The steering angular velocity θ
f '(= d? f / dt) is calculated, and the energization of the coil 42 is controlled by the processing of steps 136 to 150.

First, if the absolute value | θf '| of the steering angular velocity θf is less than a predetermined first reference value θf1, step 136
In step 144, it is determined whether or not the second flag FLG2 is "1". The second flag FLG2 represents the non-energized state of the coil 42 by "0" and the energized state of the coil 42 by "1".
It is initially set to "0". Therefore, it is first determined to be “NO” in step 144, the program proceeds to step 150, and in step 150, the coil 42
Keep power off.

In this state, the driver turns the steering wheel and the absolute value | θf '| of the steering angular velocity θf becomes the first reference value θ.
When it becomes f1 or more, it is determined to be “YES” in step 136, the program proceeds to step 138, and in step 138, the coil corresponding to the vehicle height HT is energized based on the energization map built in the computer 55. To do. As shown in FIG. 8, the energization map corresponds to the coils 42 to be energized in the forward direction among all the coils 42 (C1 to C15) corresponding to the respective upper and lower positions of the coil 42 relative to the magnets 36 and 37. The coil 42 to be energized in the opposite direction is shown. In this case, the lengths of the magnets 36 and 37 are set to be substantially equal to the width of the three coils 42, and specifically,
Regarding the magnet 36, the three coils 42, which are shifted upward by one from the three coils 42 facing each other, are energized in the opposite direction. Further, with respect to the magnet 37, the three coils 42 shifted downward by one from the three coils 42 facing each other are provided.
Is energized in the forward direction.

In this case, the relative position of the coil 42 with respect to the magnets 36, 37 corresponds to the height of the vehicle body BD with respect to the lower arm LA, and this relative height is detected as the vehicle height TH. The coil 42 to be energized can be determined by the vehicle height TH. The vertical axis of FIG. 8 represents the reference height position of the vehicle body BD with respect to the lower arm LA as "0", and the side higher than the reference height (extension side of the damper device) is sequentially represented as + a1, + a2, + a3, and the same reference height. The lower side (the contraction side of the damper device) is sequentially -a1, -a2, -a.
It is represented as 3, -a4. Therefore, as the vehicle body BD sequentially becomes higher with respect to the lower arm LA, the energized coils 42 are sequentially arranged from the higher coil 42 to the lower coil 42, that is, the coils C1 to C1.
Move to side 5.

When the coil 42 is energized by the drive circuit 58 as described above in step 138,
The magnetic poles due to the forward and reverse energization of the coil 42 are shown in FIG.
The coil 42 and the upper case 23 (on the sprung member side) to which the coil 42 is fixed have a force to maintain the position shown in FIG. 8 due to the energized coil 42 and the magnetic forces of the magnets 36 and 37. To work. That is, if the coil 42 and the upper case 23 to which the coil 42 is fixed are slightly displaced from the illustrated position in the vertical direction, a force acts to return them to the illustrated position. After the processing in step 138, the second flag FLG2 is processed in steps 140 and 142.
If is not "0", it is changed to "1".

Then, the calculated absolute value | θf '| of the steering angular velocity θf is the second reference value θf2 (θf2 <θf
1) As long as the above is true, the coil 42 corresponding to the vehicle height HT is energized through the drive circuit 58 based on the energization map in step 138 based on the determination of “YES” in both steps 144 and 146. To be done. However, as described above, when the vehicle height HT changes, the changed vehicle height H
The coil 42 is energized corresponding to T.

On the other hand, when the calculated absolute value | θf '| of the steering angular velocity θf becomes less than the second reference value θf2, step 1
When it is judged as "NO" at 46, the program proceeds to step 14
Proceed to 8,150. In step 148, the second flag FLG2 is returned to "0", and in step 150, the energization of the coil 42 is released. Then, the absolute value | θf '| of the steering angular velocity θf is again determined to be the first reference value θf1.
Until the above, the coil 42 is maintained in the non-energized state.

In this way, the absolute value of the steering angular velocity θf | θf '
When | is small, the coil 42 is kept in a non-energized state, and the upper case 23 has magnets 36 and 37 and a coil 42.
The force to maintain the current position by the electromagnetic force of and does not work. Therefore, in this state, when an external force from the road surface acts on the vehicle body BD, the vehicle body BD can move up and down relatively freely with respect to the lower arm LA, and the air spring device relieves the external force by the spring action. Therefore, the riding comfort of the vehicle is kept good. Further, when the vehicle makes a sharp turn due to the sudden turning of the steering wheel, the absolute value | θf '| of the steering angular velocity θf becomes large as shown in FIG.
Since a force for maintaining the current position by the electromagnetic force acts on the vehicle, a change in the posture of the vehicle body BD is suppressed and the steering stability of the vehicle is improved. Further, the force for maintaining the vehicle body BD at the present position by the electromagnetic force of the magnets 36, 37 and the coil 42 is not due to the generation of the relative speed of the vehicle body BD with respect to the lower arm LA as in the damper device. Since it is possible to immediately respond to the driving operation of the driver, it is possible to improve the control response of the suspension device.

In the present embodiment, switching of the damping force is controlled to be switched according to the lateral acceleration Gy as the posture information of the vehicle body BD, and whether the coil 42 is energized or de-energized is steered angular velocity θf as the driving operation information. 'It was controlled according to. However, by reversing these controls, the switching of the damping force is controlled according to the steering angular velocity θf ′ as the driving operation information, and the coil 42
The energization and de-energization may be controlled according to the lateral acceleration Gy as the posture information of the vehicle body BD. Further, as the attitude information of the body BD, various physical motion quantities such as lateral velocity, longitudinal acceleration, longitudinal velocity, yaw rate, vertical acceleration, and vertical velocity of the vehicle body BD may be used for controlling both of them. Further, a driving operation amount such as a steering angle of the steering wheel, a brake depression speed, an accelerator pedal depression speed, and a throttle opening may be used for controlling the both.

As can be understood from the above description, according to the above embodiment, both the magnets 36 and 37 and the coil 42 are outside the outer cylinder 12 and inside the cases 23 to 25 of the air spring device which are isolated from the outside. Since it is arranged in the air, the magnets 36, 37 and the coil 42 are protected without being affected by the hydraulic fluid and external dust, powder, etc., and the suspension device has high quality and good durability. Further, since the necessary magnetic lines of force do not pass through the outer cylinder 11 and the inner cylinder 12, both cylinders 1
1 and 12 can be manufactured with a low cost material such as iron. Furthermore, the air in the air spring device is usually air that has passed through devices such as an air filter and a drier, and the environmental conditions in which the magnets 36, 37 and the coil 42 are arranged are also favorable, so the magnet 3
The characteristics of 6, 37 and the coil 42 are always kept good, and the durability is also improved.

Even if the inclination of the outer cylinder 11 with respect to the vehicle body BD changes, the upper case 23 is fixed to the piston rod 13 via the support plate 27 and elastically supported on the vehicle body BD by the upper support 26. Therefore, the upper case 23 also interlocks with the piston rod 13 whose inclination changes together with the outer cylinder 11. Further, since the lower case 24 is supported on the outer circumference of the outer cylinder 11 at two points above and below the support member 32, the rib 38, and the bound stopper 31, the lower case 32 also tilts together with the outer cylinder 11. Therefore,
The upper case 23 and the lower case 24 are also integrally tilted, and the distance between the coil 42 and the magnets 36 and 37 fixed to the upper case 23 and the lower case 24 is always kept constant and generated by the magnet and the coil. The characteristics of the magnetic force are always kept constant.

Next, a modified example in which a part of the suspension device of the above embodiment is modified will be described with reference to the drawings. FIG. 10 shows a central portion of the suspension device according to the modified example.

The first feature of this modification is that the magnet 3
A through hole is provided between the magnets 36 and 37 of the supporting member 35 that supports the magnets 6 and 37 so as to penetrate from the inner peripheral surface to the outer peripheral surface and to face the inner peripheral surface of the coil assembly. In this case, the support member 35 is replaced with the sleeve member 35a.
And ring member 35b, and through holes 35a1 and 35b1 are formed at appropriate plural positions in the circumferential direction of both members 35a and 35b.
Are provided so as to be continuous. Another feature of this modification is that through holes 34a that penetrate through the lower case 24 at appropriate plural positions in the upper circumferential direction are provided, and a plurality of check valves 71 are provided on the inner peripheral surface of the case 24. That is. The check valves 71 are respectively provided at the corresponding positions of the through holes 34 a, prohibit air from passing through the through holes 34 a from the inner peripheral surface side of the lower case 24 to the outer peripheral surface side thereof, and the outer peripheral surface of the case 24 . Only the passage of air from the side to the inner peripheral surface side through the through hole 34a is allowed.

In this modification, the through holes 35a1,
Since 35b1 is provided, when the vehicle body BD is displaced downward (when the damper device is in the contracted state), the air chamber R flowing from the inside of the upper case 23 into the inside of the connecting case 25.
The air in the 4 is the coating layer 44 of the coil assembly.
Flow not only on the inner peripheral surface of but also through the through holes 35a1 and 35b1. When the coating layers 44 and 45 or the coating layers 44 and 46 stick to each other due to the deviation of the axis of the coil assembly from the axes of the lower case 24 and the support member 35 (in the case of a stick state).
In this case, the air that has passed through the through holes 35a1 and 35b1 enters between the outer peripheral surfaces of the magnets 36 and 37 and the coating layer 44, so that the flowed-in air automatically releases the stuck state. Since the through hole 34a and the check valve 71 are provided, the inside of the air chamber R4 that flows from the inside of the connecting case 25 into the upper case 23 when the vehicle body BD is displaced upward (when the damper device is in the extended state). The air mainly flows through the through hole 34a and the check valve 71. In this case, if the through hole 34a is made large to some extent, the air passing through the through hole 34a does not hinder the upward displacement of the vehicle body BD, and the vehicle body BD is displaced upward without resistance.

In the above-described embodiment and its modification, the coil assembly is fixed to the upper case 23 side via the rubber sheet 48, and the magnets 36 and 37 are fixed to the support member 35 fixed to the lower case 24. However, the magnets 36 and 37 may be fixed to the upper case 23 side and the coil assembly may be fixed to the support member 35 fixed to the lower case 24 or the lower case 24.

[Brief description of drawings]

FIG. 1 is a partial cutaway view showing an entire suspension device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a central portion of the suspension device shown in FIG.

FIG. 3 is an overall block diagram of an electric control device that controls the suspension device of FIG.

FIG. 4 is a schematic diagram showing the coils of FIGS. 1 to 3 and a drive circuit for the coils.

5 is a flowchart of a damping force switching program executed by the microcomputer shown in FIG.

FIG. 6 is a vehicle speed V and lateral acceleration Gy on a V-Gy map.
It is a graph which shows the relationship of.

7 is a flow chart of a coil energization / de-energization control program executed by the microcomputer of FIG.

FIG. 8 is an explanatory diagram for explaining a relationship between a vehicle height HT and an energization coil in an energization map.

FIG. 9 is a time chart showing a coil energization control state and a damping force switching control state with respect to changes in a steering wheel steering angle, a steering angular velocity, and a lateral acceleration (constant vehicle speed).

10 is a cross-sectional view showing a modified example of the central portion of the suspension device of FIG.

[Explanation of symbols]

11 ... Outer cylinder, 12 ... Inner cylinder, 13 ...
Piston rod, 17 ... Main piston, 18 ... Sub piston, 21 ... Actuator, 23 ... Upper case, 2
4 ... Lower case, 25 ... Connection case, 36, 37 ... Magnet, 41 ... Casing, 42 ... Coil, 44, 45, 4
6 ... Coating layer, 48 ... Rubber sheet, 55 ... Microcomputer.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasunobu Yasunobu 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (56) References: Kaihei 1-178107 (JP, U): Shokai Sho 60-98509 (JP, U) Actually open 61-156739 (JP, U) Actually open 5-22882 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16F 9/08 F16F 9 / 50

Claims (4)

(57) [Claims] 1. A cylinder having a working fluid filled therein and a piston rod projecting from the upper end surface of the cylinder so as to be able to move forward and backward, the lower end of the cylinder being assembled to an unsprung member, and the upper end of the piston rod being a sprung member. A damper device for generating a damping force by the vertical movement of the sprung member with respect to the unsprung member; and a lower end provided on the outer peripheral surfaces of the cylinder and the piston rod and supported on the outer peripheral surface of the cylinder. And an air having a flexible case whose upper end is supported by the sprung member, and which imparts a spring action to the vertical movement of the sprung member with respect to the unsprung member by the gas enclosed in the case. in the suspension device for the vehicle with a spring device, an internal of the casing and is disposed facing the outside of the front Symbol cylinder DOO Wherein a cylinder and the piston rod and the respective cylindrical magnet and a coil which is displaced integrally provided, the magnet is supported on the outer circumference of the cylinder
On the outer peripheral surface of the support member molded with a non-magnetic material into a cylindrical shape.
A suspension device for a vehicle, which is fixed . 2. An upper case, which is formed in a cylindrical shape and has an upper end portion fixed to an outer peripheral surface of a piston rod and elastically supported by the sprung member, and a lower end which is formed in a cylindrical shape. One part of the magnet and the coil, and a lower case whose part is fixed to the outer peripheral surface of the cylinder, and a connecting case which is made of a material that is easily deformable and which is connected to connect the upper case and the lower case. 2. The magnet is fixed to the upper case, and the other of the magnet and the coil is fixed to the lower case.
The vehicle suspension device described in. 3. The upper portion of the lower case is supported on the outer peripheral surface of the cylinder, and the upper portion of the lower case is supported.
The vehicle suspension device described in. 4. A cylinder in which hydraulic fluid is filled
With a piston rod protruding from the upper end surface
The lower end of the cylinder to the unsprung member.
And attach the upper end of the piston rod to the sprung member.
Decrease due to the vertical movement of the sprung member with respect to the unsprung member.
Provided on the outer peripheral surface of the cylinder and the piston rod, and a damper device that generates a damping force
And the lower end is supported by the outer peripheral surface of the cylinder.
A flexible case whose upper end is supported by the sprung member.
The gas enclosed in the case
Spring action against vertical movement of the upper member with respect to the unsprung member
Suspension of a vehicle equipped with an air spring device for applying
The device inside the case and outside the cylinder.
Facing each other, and the cylinder and the pistol
Cylinder magnet and coil
And a case, the case is formed into a cylindrical shape, and the upper surface of the case is the sprung portion.
The upper case supported by the material and the lower end formed in a cylindrical shape
The lower case with the part fixed to the outer peripheral surface of the cylinder,
The upper case and front
A cylindrical support member is provided at an upper end portion of the lower case so as to be separated from the cylinder, and one of the magnet and the coil is provided on an inner circumference of the upper case. The other side of the magnet and the coil is fixed to the outer peripheral surface of the supporting member, and a radial through hole is provided in the supporting member so as to open in the facing surface of the magnet and the coil. vehicles suspension systems it said.