JPS60193710A - Characteristic controller for car suspension - Google Patents

Abstract

PURPOSE:To improve the comfortableness by constructing the suspension characteristic controller for four-wheel car such that the pavement condition is decided through the up/down motion of wheel to operate the control information while to vary the characteristic of rear wheel suspension through delay time corresponding with the car speed. CONSTITUTION:Upon provision of the up/down stroke of front wheel 11 and the up/down acceleration 12 to a characteristic controller 10, the pavement condition predicting operation (a) is executed to determine the control data d3 for setting the characteristic of rear wheel suspension to the optimal level for the predicted pavement condition while employing the data stored in a data memory. Then the control data d3 is applied with delay processing (c) to be delayed with correspondence to the car speed 8 and outputted to the output circuit (d) as a rear wheel actuator control signal S for controlling the characteristic of the rear wheel actuator 6. With such arrangement, the vibration on coarse road is reduced thus to improve the comfortableness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a characteristic control device for a vehicle suspension on the rear wheels of a four-wheeled vehicle or the like.

(Prior Art) In general, in a vehicle, the front wheel load is greater than the rear wheel load. That is, the engine and the like are mounted at the front of the vehicle body, and the rear wheel load is kept relatively small to achieve oversteer characteristics. For this reason, the vertical movement of the rear wheels greatly affects the vibration of the vehicle.
This becomes a major factor in deteriorating riding comfort.

It would be ideal if the suspension characteristics could be variably set depending on the road surface condition, that is, the unevenness of the road surface, but the reality is that such a suspension has not been proposed in the past.

(Object of the Invention) In view of the above circumstances, the present invention estimates the unevenness of the road surface in advance to set the optimum rear wheel suspension characteristics corresponding to the road surface condition, thereby making it possible to maintain the vehicle even on rough roads. An object of the present invention is to provide a characteristic control device for a vehicle suspension that can significantly reduce vibration and dramatically improve riding comfort.

(Structure of the Invention) The present invention relates to a characteristic control device that can variably control arbitrary characteristics such as damper damping force and spring constant in a vehicle suspension. a detection means for detecting a vertical stroke and a vertical acceleration; a calculation means for estimating a road surface condition based on the detection results of the detection means; and obtaining control information for setting suspension characteristics corresponding to the road surface condition; It is equipped with a delay means for delaying a predetermined period of time corresponding to the vehicle speed, and an actuator for varying the characteristics of the suspension based on the delayed control information, and estimates the road surface condition by detecting the vertical movement of the front wheels.
As a result, after a predetermined time delay, the characteristics of the rear wheel suspension are variably controlled to be optimal for the road surface condition.

(Example) Below, preferred examples that further embody the present invention will be described in detail with reference to the drawings.

In the drawings, FIG. 1 is a schematic plan view showing the basic structure of a vehicle equipped with a vehicle suspension characteristic control device according to the present invention.

First, in order to clarify the present invention, the overall schematic configuration will be explained based on the same figure.

In the vehicle indicated by the reference numeral (1) in the figure, (2) and (2) are front wheels that are steered left and right by rotation of the steering wheel (3). (4) and (4) This rear wheel (4) forms the driving wheel that drives the vehicle (1) with the rear wheel.
, (4) are supported by suspensions (5), (5), and actuators (8), (8) for varying the suspension characteristics are connected to the suspensions (5), (5). Also, actuator (8)
, (8) is connected to a control unit (7), and this control unit (7) is equipped with a vehicle speed sensor (8) that detects vehicle speed.
and detection means (9) for detecting movement factors such as vertical movement of the left and right front wheels, such as stroke, speed, and acceleration;
0 or more, actuators (6) and (8) connecting actuators (6) and (8) respectively.
), the control unit (7), the vehicle speed sensor (8), and the detection means (9) constitute a suspension characteristic control device (10) according to the present invention.

Next, with reference to FIGS. 2 and 3, such a characteristic control device (lO) will be specifically explained. FIG. 2 is a functional block diagram showing an information processing system of a vehicle suspension characteristic control device according to the present invention, and FIG. 3 is a hydraulic circuit diagram of a hydraulic shock absorber showing an example of an actuator. The same parts are given the same reference numerals throughout the drawings to clarify their structure.

First, the detection means (8) will be explained. In the embodiment, it is composed of a stroke sensor (11) that detects the vertical stroke of the front wheel (2) and an acceleration sensor (12) that detects the vertical acceleration of the front wheel (2). As the stroke sensor (11), for example, a potentiometer or the like that can electrically detect the expansion/contraction length of the front wheel shock absorber using a slide resistor or the like can be used. Also, for vertical acceleration, a sensor that can directly detect acceleration may be installed, but in practice, the data from the potentiometer is differentiated on the computer side, which will be described later, to calculate the speed, and by differentiating this, the acceleration is calculated. can. Note that vehicle speed information is used in this case.

Next, the control unit (7) will be explained. The control unit (7) can be constructed entirely from an on-vehicle computer. Stroke data (dl) and acceleration data (d2) representing the vertical movement of the front wheel obtained from the detection means (8) as described above.
) is given to the control unit (7), first each data (
dl) and (d2) are subjected to arithmetic processing (a), and this processing (
A), the road surface condition is estimated, and control data (d3) for setting the characteristics of the rear wheel suspensions (5), (5) to optimal values corresponding to the estimated road surface condition is obtained. That is, it is possible to estimate whether the road surface condition is concave or convex, how deep or high it is, based on the stroke data (dl), and whether the concave or convex condition is sharp or gently sloped based on the acceleration data (d2). . Therefore, in the shock absorber of the rear wheel suspension (5), for example, if the road surface condition is concave, it is sufficient to lower the oil pressure, and a large amount of control data (d3) for performing this control is stored as data in the memory (if). has been done. The control data in this memory (b) is set as a data matrix, for example, theoretically calculated data or experimental data, and each data (dl)
The optimum data (d3) may be selected based on (d2). Next, this control data (d3)
is delayed for a predetermined time by delay processing (c).

This predetermined time is the time it takes for the rear wheels (4), (4) to reach just before the road surface position detected and estimated by the front wheels when the vehicle is running, and in practice, the vehicle speed sensor (8)
The delay time is set as a function of the vehicle speed data (U) obtained from the vehicle speed data (U).

This delayed control data (d4) is applied to the output circuit (d). Here, the signal undergoes necessary processing such as amplification, becomes a control signal (St), is output from the control unit (7), and is supplied to the actuator (6).

Next, the actuator (6) will be specifically explained with reference to FIG. 3.

This actuator (6) is configured as a pair with the suspension (5), is operated by a control signal (S) from the control unit (7), and variably controls the characteristics of the suspension (5) in response to the control signal (S). . These characteristics include, for example, suspension stroke, suspension stroke speed, spring constant of the shock absorber, damping force of the shock absorber, oil pressure of the shock absorber, etc., but any one or more of these characteristics Vary the size.

These variable methods can be constructed using known techniques; an example is the hydraulic shock absorber disclosed in Japanese Patent Publication No. 4B-14368. In FIG. 3, a hydraulic shock absorber (13) in a suspension (5) interposed between the rear wheels and the vehicle body is equipped with a hydraulic cylinder (15) divided into upper and lower sections by a piston (10). When one of the partitioned oil chambers (1B) or (17) reaches a certain pressure or higher, the hydraulic oil in this oil chamber (16) or (17) is pumped through the relief valve to the other oil chamber (17) or (!6). ) gushing passageway (1
8), (1111). Also, this piskiton (
14) is equipped with a switching passage (21) that communicates the upper and lower oil chambers (16) and (17) via an orifice (20), and this switching passage (21) is equipped with a switching valve (22) in series. This switching valve (22) is connected to a solenoid (23),
The passage (2) is opened and closed by the operation of the solenoid (23).The control unit (7) is connected to this solenoid (23) and a control signal (S) is supplied thereto.Thus,
The buffer (13) generates a small damping force when the passage (21) is opened, and generates a large damping force when the passage (21) is closed. In addition, orifice (20), passage (2
1), the switching valve (22), and the solenoid (23) constitute an actuator (6). A plurality of such actuators (6) may be provided in the piston (14) for different orifices so that the actuators (6) can be selected from a plurality of stepwise sizes.

The above-mentioned actuator (6) is an example, and other methods can be implemented, such as by varying the length of the torsion bar, that is, by using an actuator that fixes the fixing points at both ends of the bar at different positions, thereby varying the spring constant. Further, even if the actuator (6) is operated not only in stages but also continuously variable, better control can be achieved.

Next, the overall function of such a characteristic control device (lO) will be explained.

Assume now that the vehicle (1) is running and the front wheels (2) have passed over a bump on the road surface. In this case, the control unit (7) estimates the road surface condition by detecting that the road surface condition is a convex portion, its height, and shape (sharp or gentle), and It outputs a control signal that provides optimal rear wheel suspension characteristics. In other words, in this case, since it is a convex part of the road surface, the shock absorber (13) of the embodiment
It is only necessary to reduce the damping force of the switching valve (22).

On the other hand, in the case of four parts of the road surface, it is sufficient to close the switching valve (22).Furthermore, if the magnitude of the damping force can be selected from among a plurality of types, it is possible to select any one from among those that provide the optimum damping force. Just choose something.

The operation of the switching valve (22) is delayed for a predetermined period of time, and is performed immediately before the rear wheel (4) approaches the road surface bump, so it is optimal when the rear wheel (4) passes the road surface bump. The suspension characteristics are set as follows.

Note that it is desirable that the characteristic control device (lO) be able to control the left and right front and rear wheels as independent systems.

In the above embodiments, each process in the control unit (7) is executed by computer software (control program). In addition, only basic functions are shown in the drawings, and other accessory devices such as input interfaces required to make the computer function are omitted.

(Effects of the Invention) As described above, the vehicle suspension characteristic control device according to the present invention estimates the road surface condition by detecting the vertical movement of the front wheels, and thereby adjusts the rear wheel suspension characteristics to the relevant one after a predetermined time delay. Since the system is variably controlled to be optimal for road surface conditions, it is possible to significantly reduce vehicle vibration and dramatically improve ride comfort even on rough roads.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic plan view showing the basic structure of a vehicle equipped with a vehicle suspension characteristic control device according to the present invention, and FIG. 2 is a vehicle suspension characteristic control according to the present invention. FIG. 3 is a functional block diagram showing an information processing system of the device, and a hydraulic circuit diagram of a hydraulic shock absorber showing an example of an actuator. In the drawing, (2) and (2) are front wheels, (5) and (5) are rear wheel suspensions, (8) and (11) are actuators,
(7) is a control unit, (8) is a vehicle speed sensor, (9),
(9) is a detection means, (!ri is a stroke sensor, (12
) is an acceleration sensor, (a) is a calculation process, (b) is a memory, (c) is a delay process, (d) is an output circuit, and (S) is a control signal. Patent Applicant Honda Motor Co., Ltd. Agent Patent Attorney 1) Kuni Ohashi, Patent Attorney, Department, Yu Koyama, Patent Attorney, Department

Claims (1)

[Claims] (1) A vehicle suspension characteristic control device comprising the following configuration. (B) Detection means for detecting vertical movement of the front wheels; (B) Calculation means for estimating road surface conditions based on the detection results of the detection means and obtaining control information for setting suspension characteristics corresponding to the road surface conditions; ) a delay means for delaying the control information by a predetermined time corresponding to the vehicle speed; (d) an actuator for varying characteristics of the rear wheel suspension according to the delayed control information; (2) a detection means for detecting the vertical stroke of the front wheels; 2. The vehicle suspension characteristic control device according to claim 1, wherein the device detects acceleration in a vertical direction and an acceleration in a vertical direction.