JPS6118512A - Suspension controller for vehicle - Google Patents

Abstract

PURPOSE:To improve drive feeling and reduce the frequency in varying damping force and improve durability by memorizing the vertical vibration values in the past and selecting the set value for judging the switching of damping force, in the captioned apparatus in damping-force variation type. CONSTITUTION:An arithmetic processor 26 always controls the damping-forces of damping-force variation softening apparatuses 2a-2d by a main program, and takes-in a car-height detection signal 4 at each certain time, and temporarily memorizes the signal into a memory apparatus 27. Said memory apparatus 27 compares the max. and min. vehicle-height detected values in the past, and renews the max. and min. values accordng to the necessity. The state of road is judged from the count contents of a counter 27a during traveling, and the damping-force control signal according to the road surface is outputted into an output circuit 29 according to the result of the comparison between the difference between the memorized average vehicle-height and the vehicle-height at present and a prescribed value, and the damping forces of the softening apparatuses 2a- 2d are controlled. Thus, the frequency of damping-force switching is reduced, and drive feeling is improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a suspension control device for a vehicle, and particularly to a suspension control device for automatically controlling the damping force or spring constant of a suspension suspension device to an optimum value in accordance with the vertical vibration state of a vehicle body. The present invention relates to a vehicle suspension control device. - [Prior Art] As a conventional vehicle suspension control device, there is one described in Japanese Patent Application No. 59-8J99, which was previously proposed by the present applicant.

Generally speaking, when driving on a good road such as a paved road with a smooth road surface and no undulations, the ride comfort can be improved if the damping force and damping constant of the suspension device is low, while the relatively large When driving on a road surface with bumps and undulations, the vehicle and body sway increases, so the road surface condition is detected by a road surface condition detector and the damping force or spring constant of the suspension system is temporarily increased. This is designed to suppress changes in posture.

In other words, when a vehicle goes over a relatively large protrusion on the road surface, if the damping force or spring constant of the suspension device is low, the vehicle body generally undergoes a relatively large change in attitude, as shown by the solid line in FIG. However, if the damping force (or spring constant) is increased in this state, the change in attitude of the vehicle body can be suppressed, as shown by point vA (or a dashed line) in FIG.

By the way, in general, even if the amplitude of the vertical vibration that occurs in the car body is the same, the smoother the average roughness of the road surface, the greater the discomfort that will be felt to the passengers. It is necessary to differentiate the judgment level of vertical vibration between a smooth road and a rough road with undulations, and to lower the judgment level of the former compared to the latter to perform sensitive vibration detection.

[Problem that the invention seeks to solve]

However, in the conventional vehicle suspension system described above, the judgment level of vertical vibration is fixed at a constant value, so if the judgment level is set according to when driving on a good road such as an expressway, it will be difficult to drive on a relatively rough road. When driving on a rough road surface, the damping force or spring constant is often increased even if there are temporary protrusions or undulations that are not so large that there is no need to increase the damping force or spring constant, which worsens the riding comfort and Since the switching frequency also increases, there are unresolved issues such as the durability of the damping force or spring constant switching mechanism.

[Means for solving problems]

In order to solve the above-mentioned conventional problems, the present invention, as shown in the basic configuration diagram of FIG.
a suspension device capable of changing a spring constant or damping force; a vertical vibration detector that detects vertical vibration of the vehicle body and outputs a detection signal corresponding to the magnitude of the vertical vibration;
Vibration determining means for comparing a detected vibration value based on a detection signal from the vertical vibration detector with a predetermined set value and outputting a determination signal when the comparison result shows that the former exceeds the latter; and the vibration determining means. control means for outputting a control signal for changing the spring constant or damping horn of the suspension device based on the judgment signal from the vibration judgment means, the vibration judgment means inputting the detection signal from the vertical vibration detector to determine the past a storage means for storing the magnitude of vertical vibration; a predetermined setting value selection means for selecting the predetermined setting value based on the value stored in the storage means; a predetermined setting value selected by the predetermined setting value selection means and the predetermined setting value; Current vibration determining means compares the vibration detection value based on the detection signal from the vertical vibration detector and outputs the determination signal when the magnitude of the current vibration exceeds the predetermined set value. Features.

[Effect]

This invention detects the vertical vibration of the vehicle body with a vertical vibration detector, and compares the detected vibration value based on the detection signal with a predetermined set value using a vibration determining means to determine whether the vertical vibration of the vehicle body exceeds the predetermined set value. is determined, and when it exceeds the predetermined set value,
A judgment signal indicating this is output, and the damping force or spring constant of the suspension device is controlled by the control means based on this judgment signal, and a predetermined setting value in the vibration judgment means is set based on the past vibration stored in the storage means. The road surface condition on which the vehicle is currently traveling is estimated from the magnitude, and the predetermined setting value selection means selects a predetermined setting value according to the road surface condition, and then the predetermined setting value and the detection signal from the vertical vibration detector By comparing the detected vibration value with the current vibration judgment means, the vibration state is determined at a judgment level that corresponds to the driving road surface condition, and the suspension system is optimized according to the road surface condition while ensuring ride comfort. The problem of the conventional example described above can be solved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Fig. 2 is a schematic configuration diagram showing an embodiment of this invention, Fig. 3 is a block diagram showing an embodiment of this invention, and Fig. 4 shows an example of a variable damping force shock absorber that can be applied to this invention. The cross-sectional view and FIG. 5 are flowcharts showing the processing procedure of a control device applicable to the present invention.

First, to explain the configuration, in Fig. 2, la
, lb are front wheels, lc', ld are rear wheels, 28 to 2d are variable damping force shock absorbers as suspension devices interposed between each of the wheels 18 to 1d and the vehicle body 3, and 4 is arranged on the lower front surface of the vehicle body 3. A vehicle height detector 5 serving as a vertical vibration detector is supplied with a detection signal from the vehicle height detector 4, and based on this, predetermined arithmetic processing is performed to determine the damping force of the variable damping force shock absorbers 2a to 2d. This is a control device that controls the

An example of the variable damping force shock absorbers 28 to 2d is as shown in FIG. A bottom valve 10 is provided at the bottom of a tube 8.The piston rod 9 is divided into an upper piston rod 1) and a lower piston rod 12 in the axial direction. 12 is formed with a bypass passage 14 that bypasses the damping force generating main valve 13 that serves as a piston and directly communicates with the fluid chambers A and B, while the upper piston rod 1) is provided with an electromagnetic solenoid 15 and a plunger 16. An actuator 17 having the following is installed inside. Furthermore, the plunger 16 is positioned so as to enter into the bypass passage 14, and the plunger 16 is actuated in accordance with the energization or de-energization of the electromagnetic solenoid 15 in the actuator 17, thereby opening and closing the bypass passage 14 to allow fluid flow. This allows for direct communication between chambers A and 8 or for blocking them.

Here, the electromagnetic solenoid 15 is connected to the control device 5 via a lead wire 18, and operates the plunger 16 with an excitation current as a control signal from the control device 5, thereby changing its damping force to high and low. It becomes possible to perform switching control in stages.

In FIG. 4, reference numerals 19 and 20 indicate damping force generating orifices on the contraction side and expansion side formed in the damping force generating main valve 13, 21 and 22 a non-return valve, and 23 a return spring.

Further, an example of the vehicle height detector 4 has an ultrasonic distance measuring device configuration, and an ultrasonic receiver 4b receives reflected waves of ultrasonic waves emitted from an ultrasonic transmitter 4a and reflected on the road surface. Then, the time from the time when the ultrasonic wave is emitted from the ultrasonic transmitter 4a until the reflected wave is received by the ultrasonic receiver 4b is measured, and the measured time is multiplied by the speed of sound to determine the relationship between the road surface and the vehicle body. A vehicle height detection signal DH representing the relative position between is output.

Furthermore, an example of the control device 5 is constituted by a microcomputer 28 having at least an interface circuit 25, an arithmetic processing device 26, and a storage device 27, as shown in FIG. The detection signal DH of the vehicle height detector 4 is supplied to the input side of the interface circuit 25, and the output circuit 29 is connected to the output side. Here, when the control signal CS output from the microcomputer 28 has a logical value of "1", the output circuit 29 outputs a predetermined value of excitation current to the electromagnetic solenoid 15 of each variable damping force shock absorber 28 to 2d, When the logical value is "0", the supply of excitation current to the electromagnetic solenoids 15 of the variable damping force shock absorbers 2a to 2d is cut off.

Further, the arithmetic processing unit 26 executes predetermined arithmetic processing based on the vehicle height detection signal DH from the vehicle height detector 4 according to a processing program stored in advance in the storage device 27, and performs predetermined arithmetic processing on the basis of the vehicle height detection signal DH from the vehicle height detector 4. A control signal C8 is output from the interface circuit 25 to the output circuit 29 to control the damping force of 2d to an optimum state according to the road surface condition.

The storage device 27 stores processing programs necessary for the arithmetic processing unit 26 to perform arithmetic processing, and also updates and stores the processing results of the arithmetic processing unit 26 in a predetermined storage area.

Next, the processing procedure of the arithmetic processing unit 26 will be explained according to the flowchart of FIG.

That is, the arithmetic processing word W26 normally executes a predetermined main program based on detection signals from state detectors such as a vehicle speed detector and a steering angle detector (not shown) to control the variable damping force shock absorbers 28 to The damping force of 2d is controlled to an optimum value according to the driving condition, and in this state, the timer interrupt process shown in FIG. 5 is executed every predetermined time (for example, 20 m5ec).

Then, when the timer interrupt process shown in FIG. Memorize temporarily. Lightly, move to step ■,
It is determined whether the contents of a counter 27a provided in the storage device 27 is a predetermined number n. At this time, if the count content is other than n, the process moves to step (2), the content of the counter 27a is counted up by "1", and then the process moves to step (2).

In this step (2), the past maximum vehicle height detection value Hmax stored in the maximum value storage area of the storage device 27 is read out,
It is determined whether the vehicle height detection value H exceeds the maximum vehicle height detection value Hmax. At this time, if H>Hmax, the process proceeds to step (2), where the current vehicle height detection value H is replaced with the maximum vehicle height detection value Hmax, and then the process proceeds to step (2).

In this step (2), the past minimum vehicle height detection value Hmin stored in the minimum value storage area of the storage device 27 is read out,
It is determined whether the vehicle height detection value H is less than the minimum vehicle height detection value Hmin. At this time, if H<Hmin, the process moves to step (2), where the current vehicle height detection value H is replaced with the minimum vehicle height detection value Hmin, and then the process moves to step (2).

In this step (2), the average vehicle height value H detected in advance and stored in the storage device 27 is read out, and the absolute 4fil rT − of the value obtained by subtracting the current vehicle height detection value H from this average vehicle height value H is read out.
It is determined whether H1 is greater than or equal to a predetermined set value Hbot. In this case, the determination is to determine whether the change in the posture of the vehicle body 3 due to vertical vibration affects the ride comfort for the occupants, and when IH-Hl≧Hbot, the process moves to step (2). After presetting the bottoming timer 27b provided in the storage device 27 to a predetermined value, the process moves to step [phase].

In this step [phase], it is determined whether the bottoming timer 27b preset in step (2) has timed up. At this time, if the timer 27b is before time-up, the process moves to step O, counts down the contents of the timer 27b by "1", and then moves to step 0.

In this step @, a control signal C3 with a logic value "1" for controlling each damping force variable shock absorber 2a to 2d to a high damping force is output to the output circuit 29, and then the interrupt processing is ended and the main Return to program.

Further, the determination result of step (2) is stored in the counter 27a.

When the count contents of and the predetermined value n are equal, the process moves to step 0, the contents of the counter 27a are cleared, and then the process moves to step (2).

In this step (2), the maximum vehicle height value Hmaχ stored in the maximum vehicle height storage area and the minimum vehicle height storage area of the storage device 27 is
and the minimum vehicle height value Hmin, and calculate the difference value (H
max − Hmin ) multiplied by a predetermined value α ((Hm
ax - Hmln ) xα) is updated and stored as the predetermined setting value Hbot in the predetermined setting value storage area of the storage device 27, and then the process moves to step (2).

In this step [phase], the current vehicle height detection value H is set as the maximum vehicle height value Hmax and the minimum vehicle height value Hmin in the storage device 27.
The vehicle height value is updated and stored in the maximum vehicle height value storage area and the minimum vehicle height value storage area.

Furthermore, when the determination result of step (2) is H≦Hmax, the process directly proceeds to step (2), and similarly, when the determination result of step (2) is H≧Hmin, the process directly proceeds to step (2).

Furthermore, the determination result of step ■ is l f't −H
When l < Hbot, continue with step [
phase].

Also, the judgment result of step [phase] is determined by bottoming timer 2.
When 7b is time-up, the process moves to step [phase] and outputs a control signal CS of logical value "0" to the output circuit 29 to control the variable damping force shock absorbers 28 to 2d to a low damping force, and then outputs the control signal CS to the output circuit 29. Finish the loading process and return to the main program.

Here, the processing from step ■ to step ■ is a specific example of a storage means that stores the magnitude of past vertical vibrations, and
The process of step (■) is a specific example of the current determination means, furthermore, the process of steps [phase] to step 0 and step [phase] is a specific example of the control means, and furthermore, the process of step (2) is a specific example of the current determination means. This is a specific example of the selection means.

In addition, in the above timer interrupt processing, the average vehicle height value H is
When the vehicle is stopped, the detection signal DH of the vehicle height detector 4 at that time is read, and this is stored as the average vehicle height value H in the average vehicle height value storage area of the storage device 27, or a predetermined value is set in advance. This may be stored in the average vehicle height value storage area. In addition, in step [phase] in the above timer interrupt processing, the current vehicle height value H is changed to the maximum vehicle height value H.
Although a case has been described in which the average vehicle height value H is stored as the maximum vehicle height value Hmax and the minimum vehicle height value Hmin, the average vehicle height value H may be stored as the maximum vehicle height value Hmax and the minimum vehicle height value Hmin, Also, H
It is sufficient that max and Hmin are values that can be reliably re-centered in accordance with the road surface condition in the subsequent processing of steps (2) to (2). That is, the detection accuracy may be improved by specifically setting a sufficiently small value for Hmax and a sufficiently large value for Hmin.

Next, the effect will be explained. Assuming that the vehicle is currently traveling on a good road such as a highway with a smooth surface and no undulations, the timer interrupt process shown in FIG. 5 is executed at predetermined time intervals. At this time, assuming that the count content of the counter 27a has not reached the predetermined value n, first, in step (2), the detection signal DH of the vehicle height detector 4 is read, and the value is set as the current vehicle height detection value H and stored in the memory. The current vehicle height is stored in the current vehicle height storage area No. 27.

Next, the process moves to step (2), but since the count content of the counter 27a is less than the predetermined value n, the process moves to step (2), where the count content of the counter 27a is counted down by "1", and then the process moves to step (2). do.

At this time, since the vehicle is traveling on a good road, there is little vertical vibration of the vehicle body 3, and the detection signal DH output from the vehicle height detector 4 has a small amplitude, and the maximum vehicle height value H+nax and the minimum vehicle height value Hmin are small. The difference between
Becomes a nearby value. Therefore, in the process in which the value of the vehicle height detection signal DH gradually increases in step (2), the current vehicle height detection value H becomes a larger value compared to the previous maximum vehicle height value Hmax, so if H>Hmax. Judgment is made and the process moves to step (■).

Therefore, in step (2), the current detected vehicle height value H is stored as the maximum vehicle height value Hmax, and then the process proceeds to step (2).

In this step (2), in the process where the value of the vehicle height detection signal DH gradually increases, it is determined that H≧Hn+in.
Move to step ■.

In this step ■, the average vehicle height value H and the current vehicle height detection value H
It is determined whether the absolute value of the difference between Therefore, l Hmax − Hmin l < H
It is determined that it is a bot and the process moves to step [phase]. Therefore, since the timer 27b is not clocked at step O and maintains the time-up state, step [
phase], and the variable damping force shock absorber 2a~
Control signal CS with logical value “O” to control 2d to low damping force
is output to the output circuit 29, the interrupt processing is ended, and the process returns to the main program.

In this way, the output circuit 29 receives a control signal C having a logic value of "0".
When S is output, the excitation current output from this output circuit 29 is cut off, and each variable damping force shock absorber 2
Since the electromagnetic solenoids 15 a to 2 d are maintained in a non-energized state, the plunger 16 is raised by the force of the return spring 23 to release the bypass path 14 . For this reason,
The fluid chambers A and B are communicated with each other by a bypass passage 14, and a contraction side orifice 19 and an expansion side orifice 2 are connected to each other.
0, the fluid resistance is reduced and the damping force is reduced. As a result, each variable damping force shock absorber 28 to 2d is controlled to a low damping force, so that
It is possible to maintain good riding comfort when driving on a good road.

Then, the processing of the above steps ① to ``phase'' and ``phase'' is continued until the count content of the counter 27a reaches a predetermined value n or until IH-H1≧Hbot, during which the maximum vehicle height value Hmax and minimum vehicle height Hm
in is stored in a predetermined storage area of the storage device 27.

When the count value of the counter 27a reaches a predetermined value n by continuing this good road running state, the process moves from step (2) to step [phase], where the counter 27a is cleared, and then the process moves to step (2), and the above process is performed. Read the maximum vehicle height value Hmax and minimum vehicle height value Hmin stored in the storage device 27, and based on these, (Hmax − Hmln )
After calculating Xα and updating and storing it as a new predetermined setting value Hbot in the predetermined setting value storage area of the storage device 27, the process moves to step [phase]. In this case, the predetermined set value H
When the vehicle is traveling on a good road, the bot sets the predetermined value because there is almost no difference between the stored maximum vehicle height value Hmaχ and the minimum vehicle height value Hmin in the past through the processing of steps ■ to step ■. The value of the value Hbot is a relatively small value, and therefore the judgment level in step (2) is lowered, so changes in the posture of the vehicle body due to relatively small irregularities on the road surface are reliably detected and the variable damping force shock absorber 28~ 2d is controlled to a high damping force, thereby reliably preventing changes in the posture of the vehicle body and eliminating discomfort for the occupants. In addition, when the vehicle is traveling on a road surface with rough average roughness such as a undulating road surface, the difference between the maximum vehicle height value Hmax and the minimum vehicle height value Hmin stored in the past becomes large due to the processing of steps ■ to step ■. Therefore, the value of the predetermined-set value Hbot becomes a relatively large value, and therefore the judgment level in step (3) increases, so that the change in attitude of the vehicle body 3 due to relatively small irregularities on the road surface becomes insensitive to Riding comfort can be improved without changing the necessary damping force.

In this condition of driving on a good road, when passing through unevenness such as road joints, manholes, and steps that exceed the predetermined set value Hbot, the process of steps ■ to step ■ or steps ■, step ■, step 0 to step [phase] must be performed. After the process, the process moves to step (2), and since the difference between the current vehicle height detection value I and the average vehicle height H during normal driving becomes large i, it is determined in step (2) that 1Ff-H1≧Hbot.

Therefore, the process moves to step ■, where the bottoming timer 27b is preset to a predetermined set value, and then the process moves to step [phase]. Since the timer 27b has not timed up, the process moves to step ■, and the count contents of the timer 27b are is counted down by "1", then moves to step 0, and each variable damping force shock absorber 28 to 2d
After outputting a control signal CS with a logical value of "1" to the output circuit 29 to control the damping force to a high damping force, the interrupt processing is ended and the main program is returned.

In this way, the output circuit 29 receives a control signal C having a logic value of "1".
When S is supplied, an excitation current of a predetermined value is output from the output circuit 29 to the electromagnetic solenoids 15 of each of the variable damping force shock absorbers 2a to 2d. Therefore, each electromagnetic solenoid 15 is activated, and the plunger 16 is lowered against the return spring 23 to close the bypass path 14.

Therefore, the space between the fluid chambers A and B is the contraction side orifice 19.
The damping force is increased because the damping force is communicated only with the extension side orifice 20. As a result, each of the variable damping force shock absorbers 2a to 2d is controlled to a high damping force, thereby suppressing the vertical vibration of the vehicle body when the vehicle passes over uneven road surfaces, as shown by the dotted line in FIG. It is possible to prevent changes in the posture of the vehicle body 3 and improve riding comfort.

These variable damping force shock absorbers 2a to 2b
The state of maintaining a high damping force continues until the timer 27b times out, and when the timer 26ab times out, the state shifts from step [phase] to step [phase] and each variable damping force shock absorber 2a to 2b is maintained at a high damping force. A circuit 2 that outputs a control signal CS with a logic value of “0” to control the damping force to a low level.
9, each variable damping force shock absorber 28~
2d is controlled to a low damping force. For this reason, the variable damping force shock absorber 2a~
2b is controlled.

Furthermore, when the heavy vehicle is traveling on a rough road that has undulations that cause changes in the posture of the vehicle body, the value of the maximum vehicle height Hmax in the vertical vibration storage processing of steps ``■'' to ``■'' increases, and The minimum vehicle height value Hmin becomes smaller, and the difference between the two becomes larger. For this reason, after sampling a predetermined number of times n, the process moves to step (2) and (Hma
x − Hmln ) When Xα is calculated, the calculated value becomes a large value, and this is stored as a new predetermined setting value Hbot in the predetermined setting value storage area.

Therefore, the judgment level in step (3) increases, and when the difference between the current vehicle height detection value H and the normal Koji average vehicle height value H becomes larger when driving on a rough road than when driving on a good road, Proceeding to step ■, presetting the bottoming timer 27b to a predetermined value, then proceeding to step 0 via step [phase] and step ■,
Each of the variable damping force shock absorbers 28 to 2d is controlled to have a high damping force, and the variable damping force shock absorbers 2a to 2d have a high damping force only when passing through a relatively large uneven portion that affects the ride comfort of the vehicle. Riding comfort is not impaired.

In the above embodiment, a case was explained in which the damping force variable shock absorbers 28 to 2d were applied as the suspension device, but the damping force variable shock absorbers 28 to 2d are not limited to this, and as shown in FIG. A variable spring constant spring device 30 that can change the spring constant can also be applied.

That is, the variable spring constant spring device 30 includes a shock absorber 31 and an air chamber 32 that is integrally formed in the upper part of the shock absorber 31 and is expandable and retractable in the vertical direction.

It consists of The variable spring constant spring device 30 attaches the upper end of the piston rod 33 and the upper end of the air chamber 32 of the shock absorber 31 to members of the three vehicle bodies, and attaches the lower end of the shock absorber 31 to members on the wheels 18 to 1d side. By installing it, it is attached to the vehicle.

Here, when the electromagnetic on-off valve 34 is closed, the spring constant of the variable spring constant spring device 30 is determined only by the volume of the air chamber 32. On the other hand, when the electromagnetic on-off valve 34 is opened to communicate the air chamber 32 and the reservoir tank 35, the variable spring constant spring device 30 is
The spring constant of is determined. Therefore, the electromagnetic on-off valve 34
By opening and closing the spring constant variable spring device 3
The spring constant of the 0 air spring can be switched to two levels: large and small. This spring constant switching control is performed by the third
By supplying an excitation current from the control device 5 shown in the figure to the electromagnetic opening/closing valve 34, the control signal CS is set to a logical value of "1".
”, the electromagnetic on-off valve 34 is closed to increase the spring constant, while when the control signal CS has a logical value of “0”, the electromagnetic on-off valve 34 is opened and the spring constant is decreased.

In FIG. 7, 36 is an elastic body such as rubber, 37 is an air passage, 38 is an air passage communicating with another variable spring constant spring device 30, 39 is an intake/exhaust valve, and 40 is an air supply device.

Further, as the suspension device, it is not limited to the case where a variable damping force shock absorber or a variable spring constant spring device is applied alone, but it is also possible to use both in combination.

Furthermore, in the above embodiment, the damping force of the variable damping force shock absorbers 2a to 2d is configured to be able to be switched to two levels, high and low. It is also possible to apply a variable damping force shock absorber.

Furthermore, in the above embodiment, a case has been described in which the control device 5 is configured by the microcomputer 28, but instead of this, it may be configured by combining electronic circuits such as a comparison circuit, a logic circuit, and a peak hold circuit. can.

Furthermore, in the above embodiment, a case has been described in which the vehicle height detector 4 configured as an ultrasonic distance measuring device is applied as a vertical vibration detector for detecting vertical vibration of the vehicle body, but the invention is not limited to this. , a displacement detector that detects the amount of relative displacement between the piston rod and cylinder tube of a variable damping force shock absorber, or a transmission force detector such as a piezoelectric element that detects the transmission force due to the unsprung and main vibrations of the vehicle, A vertical vibration detector such as an acceleration detector that detects the acceleration of vertical vibration can be applied.

〔Effect of the invention〕

As explained above, according to the present invention, the magnitude of vertical vibration is stored in the storage means based on past driving conditions, and the damping force or spring constant of the suspension device is switched by the predetermined setting value selection means based on the stored value. A predetermined setting value serving as a judgment level is selected according to the road surface condition, this predetermined setting value and the current vertical vibration detection value are compared by the current vibration judgment means, and when the latter exceeds the former, the suspension device is activated. Since it is configured to increase the damping force or spring constant,
It is now possible to change the predetermined set value according to the average roughness of the road surface, effectively reducing vehicle body vibration and improving ride comfort, without causing discomfort to the occupants. It will be done.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the basic configuration of this invention, Figure 2 is a schematic diagram showing one embodiment of this invention, Figure 3 is a block diagram showing one embodiment of this invention, and Figure 4 is a block diagram showing one embodiment of this invention. FIG. 5 is a sectional view showing an example of a variable damping force shock absorber applicable to the invention, FIG. 5 is a flowchart showing the processing procedure of the control device, and FIG. 6 is a sectional view showing another embodiment of the suspension device applicable to the invention. 7 are waveform diagrams showing the amount of vertical vibration of the vehicle body. Ia, lb...front wheel, 1c, 1d...
Rear wheel, 2a to 2d... variable damping force shock absorber (suspension device), 3... vehicle body,
4...Vehicle height detector (vertical vibration detector), 5...
... Control device, 14 ... Bypass path, 15
...Electromagnetic solenoid, 16...Plunger, 25.Old...Interface circuit, 26...
...Arithmetic processing unit, 27...Storage device, 27
a...Counter, 27b...Bottoming timer, 28...Microcomputer, 2
9... Output circuit, 30... Spring constant variable spring device (suspension device), 31...
... Shock absorber, 32 ... Air chamber,
34... Solenoid on-off valve, 35... Reservoir tank.

Claims (4)

[Claims] (1) A suspension device that can change the spring constant or damping force by inputting a control signal, and a vertical vibration detector that detects vertical vibration of the vehicle body and outputs a detection signal corresponding to the magnitude of the vertical vibration. and comparing the vibration detection value based on the detection signal from the vertical vibration detector with a predetermined setting value,
vibration determining means for outputting a determination signal when the comparison result shows that the former exceeds the latter; and a control signal for changing the spring constant or damping force of the suspension device based on the determination signal from the vibration determining means. control means;
The vibration determining means includes a storage means for inputting a detection signal from the vertical vibration detector and storing the magnitude of vertical vibration in the past, and a predetermined setting for selecting the predetermined setting value based on the stored value of the storage means. A value selection means compares the predetermined setting value selected by the predetermined setting value selection means with a vibration detection value based on the detection signal from the vertical vibration detector, and determines that the current magnitude of vibration is equal to the predetermined setting value. and current vibration determining means for outputting the determination signal when the vehicle exceeds the current vibration. (2) The vehicle suspension control device according to claim (1), wherein the storage means is configured to store the magnitude of vibration as a difference between a maximum vehicle height value and a minimum vehicle height value. (3) The vehicle suspension control device according to claim (1), wherein the storage means is configured to store the magnitude of vibration within a predetermined period of time or within a predetermined travel distance. (4) The vehicle suspension control device according to claim (1), wherein the predetermined value setting means is configured to set the predetermined value as a value proportional to the magnitude of vibration.