JPS6137511A - Shock absorber controlling device of vehicle - Google Patents

Abstract

PURPOSE:To suppress vehicle vibration quickly so as to secure excellent comfort in drive by controlling a variable shock absorber of damping force at its higher damping force for a period of the specified time based on the result of a peak time inspection. CONSTITUTION:A control device carries a microcomputer 30 with input and output ports, and memory systems such as CPU, RAM, and ROM. A detected signal DV from a speed detector 1 is directly transmitted to theinput port. Simultaneously, a detected deviation signal Sa through Sd from deviation detecting devices 2a through 2d through a multiplexer 32 and an AD converter 33, are also transmitted to the computer. In addition, control signals CSa through CSd in a form of logic value 0 or 1 from the output port, are outputted to drive transistors 34a through 34d which are connected to a DC power source in series with electromagnetic solenoids 4a through 4d of variable shock absorbers of damping force 6a through 6d providing excellent comfort in drive for any road condition.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention improves riding comfort and wheels by adjusting the transmission force transmitted to the vehicle body via the shock absorber by controlling the damping force of the shock absorber. The present invention relates to a vehicle shock absorber control device that can improve ground contact.

[Prior Art]' A conventional shock absorber control device for a vehicle is disclosed in, for example, Japanese Patent Laid-Open No. 58-30542.

This device is incorporated into a hydraulic shock absorber and includes a variable orifice whose flow cross section can be adjusted in order to change the damping force of the shock absorber, and a shock absorber to change the flow cross section of the variable orifice. A solenoid built into the absorber, a vehicle height sensor that electrically detects the vehicle height value, and an excitation current supplied to the solenoid based on the detection signal of the vehicle height sensor to reduce the flow cross-sectional area of the variable orifice. and a control circuit that increases the damping force of the shock absorber under predetermined vehicle height conditions, thereby controlling the damping force of the shock absorber according to the driving conditions to improve ride comfort. This is what I did.

[Problem that the invention seeks to solve]

The conventional shock absorber control device described above is configured to control the damping force of the shock absorber in two stages, high and low, depending on the driving conditions, regardless of the shape of the road surface unevenness. There has been a problem in that the transmitted excitation force cannot be appropriately attenuated, and phenomena such as rolling, pitching, or rolling back of the vehicle body occur due to the rocking of the vehicle body, making it impossible to improve ride comfort. In other words, if the shock absorber is controlled to a low damping force, even small vibrations due to the smoothness of the road surface cannot be suppressed completely, and if the shock absorber is controlled to a high damping force on a moderately rough road with some undulations. If the damping force is controlled to be too low, the damping force becomes unnecessarily high, and if the damping force is controlled to be low, the vehicle body will shake, which leads to a worsening of ride comfort.

[Means for solving problems]

As a means for solving the problems of the conventional example, the present invention provides a vehicle shock absorber that controls a shock absorber whose damping force can be changed by inputting a control signal, as shown in the basic configuration diagram of FIG. In the control device,
Displacement or transmission force detection means for detecting the displacement or transmission force of the shock absorber; and peaks for detecting the peak points of the extension side and contraction side of the shock absorber, respectively, based on the detection signal of the displacement or transmission force detection means. The shock absorber is characterized by comprising a time point detection means and a control means for increasing the damping force or spring constant of the shock absorber for a predetermined period of time based on the detection signal of the peak time point detection means.

[Effect]

This invention detects the displacement amount or transmission force transmitted to the vehicle body by the displacement amount or transmission force detection means, and supplies the detection signal to the peak value detection means, thereby detecting the extension side and the contraction side of the shock absorber. Each peak point is detected, and from the detected point, the damping force of the shock absorber is set to a high damping force by the control means to suppress the transmission force that causes a change in the posture of the vehicle body, thereby improving the ride comfort of the vehicle and the grounding of the wheels. It is something that can improve your sexuality.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIGS. 2 to 12 are diagrams showing one embodiment of the present invention.

1 First, the configuration will be explained. In Figure 2, l
is a vehicle speed detector that outputs a detection signal according to the vehicle speed,
2a to 2d are displacement detection means, 3 is a control device, 4a to 4
d is a damping force variable shock absorber 6a to 6, which will be described later.
d electromagnetic solenoid.

As shown in FIG. 3, each of the displacement detection means 2a to 2d is attached to each wheel 5a to 5d of the vehicle and a variable damping force shock absorber 6a to 6d mounted between the vehicle body.

Each of the variable damping force shock absorbers 6a to 6d is
As shown in FIG. 4, a piston 9 attached to the lower end of a piston rod 8 and a free piston 10 are slidably disposed in the cylinder tube 7. fluid chamber A,
B and C are defined. The fluid chambers A and B are filled with a working fluid such as hydraulic oil, and the fluid chamber C is filled with high pressure gas. The piston 9 has a fluid passage 1 whose upper end is bored into the piston rod 8.
A central opening 12 that communicates with the fluid chamber A through the central opening 12 and a fluid passage 13 that communicates with this and with the fluid chamber B are formed, and within the central opening 12, fluid passages 11 and 13 are connected. A cylindrical spool 15 provided with a through hole 14 is slidably disposed. This spool 15 is always
It is urged downward by the return spring 16, and its lower position contacts the plunger 17, and the lower end of the plunger 17 contacts the bottom surface of the case 18, thereby being regulated. Therefore, the fluid passages 11 and 13 are in a non-communicating state, and the damping force is set to a high damping force as shown by the solid curve IIH in FIG. . Further, the plunger 17 is supplied with an exciting current 1a~! by the control device 3 via the lead wire 19 to the electromagnetic solenoids 4a~4d arranged around the plunger 17. By energizing d, the spool 15 is moved upward in proportion to the value of the excitation current 1a-1d, and as a result, the spool 15 is displaced upward against the return spring 16, and the spool 15 is moved upward by the through hole 14. The opening area between the fluid passages 11 and 13 is increased, and the damping force thereof is changed to a low damping force state as shown by the dashed line curve 2 in FIG.

A cylindrical cover 20 whose lower end reaches the cylinder tube 7 and covers it is integrally attached to the upper end of the piston loft 8, and the cylinder tube 7 and the piston rod are attached to the inner peripheral surface of the cover 20. A displacement detecting coil 21 is wound around the coil 21, which detects the relative displacement of the cylinder 8 (i.e., the sprung-unsprung relative displacement of the vehicle) as a change in inductance due to a change in the amount of overlap between the cover 20 and the cylinder tube 6.

As shown in FIG. 6, this detection coil 21 is incorporated into an LC oscillation circuit 22 as a coil that determines its oscillation frequency. This oscillation output is supplied to the frequency-voltage conversion circuit 23, and from this, a displacement is generated with a voltage according to the relative displacement amount of the cylinder tube 7 and piston rod 8 as shown in FIG. An amount detection signal 5axSd is output.

Then, the displacement detection coil 21, the LC oscillation circuit 22, and the frequency-voltage conversion circuit 23 are used as the displacement detection means 2a to 2d.
It consists of

As shown in FIG. 2, the control device 3 has a microcomputer 30 having an input/output board, a processing unit (CPU), storage devices such as RAM, ROM, etc., and the input port is equipped with the vehicle speed detector. The vehicle speed detection signal DV of l is directly supplied, and each displacement amount detection means 23 to 2d
Displacement amount detection signals Sa to Sd are supplied via the multiplexer 32 and A/D converter 33, and control signals CS a to CS of logic value "0" or logic value "1" are output from the output side boat. d is connected to a DC power source (not shown), and a drive transistor 34a is inserted in series with the electromagnetic solenoids 4a to 4d of the variable damping force shock absorbers 6a to 6d.
-Output to 34d.

Then, the microcomputer 30 executes arithmetic processing according to a timer interrupt processing program that is prestored in the ROM and is executed every 20111 seconds, for example, as shown in FIG.

That is, in step ■, the vehicle speed detection signal DV is read,
For example, the vehicle speed is calculated by measuring the number of pulses per unit time, and this is temporarily stored as the vehicle speed detection value V in the RAM of the storage device. - Next, the process moves to step (2) to determine whether or not the two vehicles are stopped. The determination in this case is made by reading out the vehicle speed detection value V stored in step (2) above and determining whether or not V=O.

Seventh, when the vehicle is stopped, proceed to step
Control signal CS with logical value “O” to control d to high damping force
After outputting a - CS d to the drive transistors 343 to 34d, the main program is returned to, and when the vehicle is running, the process moves to the damping force control processing from step (2) onwards.

In the damping force control process, first, in step (2), the detection signals 3i (i=a) of each displacement amount detection means 2a to 2d are detected.

b, c, d) are read and temporarily stored in a predetermined storage area of the storage device as displacement amount detection values Xi.

Next, the process proceeds to step (2) to calculate the differential value of the relative displacement detection value Xi, that is, the amount of change Xi per unit time, and temporarily stores this in the RAM of the storage device.Next, the process proceeds to step (2), The amount of change Xi calculated in step ① above
It is determined whether the absolute value of is greater than or equal to a predetermined set value α.

In this case, the determination is to determine whether the change in relative displacement is toward the peak value on the elongation side or the contraction side, and when the amount of change Xi is large, it is determined that the change is toward the peak value. , move to step ■.

In this step (2), the control flag F is set to "l" and then the process proceeds to step (2), where it is determined whether or not change 1'i<i is approximately zero and the control flag F is set to "l". Determine. The determination in this case is to determine whether the relative displacements of the shock absorbers 68 to 6d have reached the peak value, and when the peak value has been reached, the process moves to step (2).

In this step (2), the period Tn from the time when the previous peak value is reached to the time when the current peak value is reached is measured by a timer, etc., and the period Tn is stored in the RAM of the storage device, and
Read out the current cycle Tn and the past three cycles Tn-3rTn-z and Tn-t stored in the RAM, calculate the average value Txi of these, and store this in the RAM of the storage device. Move to step [phase]. Note that when the period Tn is long or in the initial state, the average period Txi is set to a predetermined value until a predetermined number of periods Tn are stored, for example, the period of relative displacement in normal running, that is, the sprung mass resonance frequency or 2 of the pitching period. Set the corresponding value TO.

In this step [phase], the average period T x i stored in the step [share] is read out, and the value of A is stored in the RAM.
The precent value T of the timer formed in the predetermined storage area of
1, and temporarily stores this in a predetermined storage area of the RAM, and then proceeds to step O.

Here, by setting the preset value of the timer to the average period, it is possible to set the precent value to the A period of the vibration frequency of the relative displacement amount, and it is possible to accurately exhibit the vibration damping effect described later. I can do it. Moreover, the preset value TM of the time limit timer is the peak period! in the initial state when starting the process shown in FIG. Although l1lTxi is set to a predetermined setting value To until the required number of items is stored, processing according to the actual relative displacement can be performed from the fourth time when the required number of items has been stored. In this case, since the timer interrupt processing is executed in an extremely short time of 2Qmsec, the influence of the error in the initial state on the running state can be ignored. In step 0, the above step [phase]
The preset value Tr+ stored in is preset to the timer, and then the process moves to step 0, where the control flag F is set to “
0" and moves to step 0. In this step 0, the variable damping force shock absorber 61
After outputting a control signal CSi of logic value "0" to the drive transistor 34i to control the damping force to a high damping force, the process moves to step (2).

In this step 0, it is determined whether or not the time limit timer has timed up, and when the time has expired, the process moves to step [phase] where the variable damping force shock absorber 61
is maintained at a high damping force and the interrupt processing ends.

Also, the determination result of step (■) is 1. When Xil <a, the process moves to step [phase] and the control flag F is set to “
0”, and if it is “1”-,
The process proceeds to step (3), and when the result is "O", the process proceeds to step O, where a control signal C3i with a logical value of "1" for controlling the variable damping force shock absorber 61 to a low damping force is output, and then the interrupt processing is performed. end.

Further, if the determination result in step (2) is x#0 - and the control flag F is not "1", the process moves to step (2). Similarly, if the determination result in step (2) is that the time limit timer is before the time amplifier, the process moves to step 0.

Here, the processing of steps ■ to step ■ and step [phase] is a specific example of the peak point detection means, and step
~Step [phase] processing is a specific example of the control means.

Next, the effect will be explained. Assume that the vehicle is currently parked or stopped, and in this state the interrupt process shown in FIG. 8 is executed at predetermined time intervals. First, in step The signal DV is read and the detected vehicle speed value (■) is calculated based on this. At this time, since the vehicle is stopped, v=0, and it is determined that the vehicle is stopped at step (2), and the logic goes to step (2) to control all variable damping force shock absorbers 6a to 6d to high damping force. Control signals C3a-C3d of value "0" are output to drive transistors 34a-34d.

In this way, the drive transistors 34a to 34d have a logical value "
When the control signals C3a to CSd of 0'' are supplied, these drive transistors 34a to 34d are turned off, and the supply of excitation current to the electromagnetic solenoids 4a to 4d of the variable damping force shock absorbers 6a to 6d is cut off. The electromagnetic solenoids 4a to 4d are maintained in a non-energized state.

Therefore, since the spool 15 is held in the lowered position by the return spring 16, the through hole 14 and the fluid passage 13 are held in the auait position, and the fluid passage 1
1 and 13 are cut off, and fluid chambers A and B
The fluid resistance between them increases, and the damping force of the variable damping force shock absorbers 6a to 6d is increased. As a result, when the vehicle is stopped, it is possible to prevent the vehicle body from tilting due to passengers getting on and off the vehicle, and to maintain a stable vehicle body posture.

Then, the stop control processing in steps (2) to (2) continues until the vehicle starts running.

Next, when the vehicle starts running, the pulse interval of the vehicle speed detection signal DV from the vehicle speed detector 1 becomes shorter, so the vehicle speed detection value V calculated in step (2) becomes V≠0. Therefore, the process moves from step ① to step ②, and the cylinder tube 7 of the variable damping force shock absorbers 6a to 6d is
and the detection signals 5a=Sd of the displacement amount detection means 2a to 2d representing the amount of relative displacement between the piston rods 8 and are stored in a predetermined storage area of the storage device as relative displacement detection values Xi.

Next, the process proceeds to step (2), where the differential value Xi of the relative displacement detection value Xi is calculated and temporarily stored, and then the process proceeds to step (2), where the absolute value IX of the relative displacement detection value Xi is calculated.
It is determined whether or not i l is greater than or equal to a predetermined set value α. At this time, if the vehicle is running on a flat and good road, the transmission force transmitted to the vehicle body (not shown) through the wheels 1a to 1d is small and there is almost no vertical vibration of the vehicle body. Therefore, the change in relative displacement between the cylinder tube 7 and piston rod 8 of the variable damping force shock absorber 61 is extremely small. Therefore, it is determined in step (2) that 1xif<a, and the process moves to step [phase]. This step [phase]
Then, it is determined whether the control flag F is 0'' or not. However, in the above-mentioned driving condition on a good road, there is no transition to step ■, so the control flag F is always 0''. A control signal C with a logic value of “0” that controls all variable damping force shock absorbers 61 to a low damping force.
3i is output to drive transistors 34a to 34d.

In this way, when the control signals C3a-C3d of logical value "1" are supplied to the drive transistors 342-34d, these drive transistors 34a-34d turn on,
When the excitation current is applied to the electromagnetic solenoids 4a to 4d of the variable damping force shock absorbers 6a to 6d. Therefore, the electromagnetic solenoids 4a to 4d are energized, so the plunger 17 is raised and the spool 1
4 is raised against the return spring 16, and the through hole 1
4 and the fluid passage 13 (this reduces the fluid resistance between the fluid passages 11 and 13, facilitates the inflow and outflow of the working fluid between the fluid chambers A and B, and reduces the damping force. As a result, it is possible to ensure a comfortable ride even when driving on a good road.

Also, from this good road running condition, 90° as shown in Fig. 9(a)
A recess is formed on the road surface, and the wheels 1a=1d are placed in this recess.
For example, when the wheel 1a is engaged, the locking wheel is displaced downward, and the relative displacement between the sprung and unsprung parts is reduced as shown in Fig. 9(b). , gradually increases. Therefore, the relative displacement change ■Xa in step ■ becomes thicker and becomes greater than the predetermined set value α. When this state is reached, the process moves from step ■ to step ■, and the control flag F is set. Set it to “1”, then step ■
It is determined whether the peak value has been reached. At this time, since Xa''-0 is not reached until the peak value is reached, the process moves to step O, and the variable damping force shock absorber 61 is subsequently controlled to a low damping force.

Thereafter, when the relative displacement amount Xa reaches the peak value at time t1, the change N()iCa becomes approximately zero, so the process moves from step (2) to step (2) to calculate the peak period. At this time, since this is the first peak, the predetermined value To is stored in a predetermined storage area of the storage device as the peak period Tx.

Next, the process moves to step [phase], and the peak period MTxi is
A preset value TM of the timer is calculated by calculating l, and this is stored in a predetermined storage area of the storage device. after that,
Move to step ■ and set the timer to the preset value TM.
After setting the variable damping force shock absorber 6 to step @, the control flag F is reset to "0", and in step 0, the variable damping force shock absorber 6 corresponding to the wheel 1a engaged with the recess is set.
Control the damping saw in a to a high damping force. Next, since the timer is set in step 0, the process returns to step 0, and repeats step 0 and step (2) until the timer times out, and the variable damping force shock absorber 6a is maintained at a high damping force. . the result,
It can exert a large vibration damping effect on the vehicle body, and can prevent changes in the vehicle's attitude.

Then, when the timer times up at time t2, when a time corresponding to the precent value TH set in the timer is elapsed from time t1, the process moves from step ■ to step [phase], and the variable damping force shock absorber 6a is set to low damping. A control signal CS with a logical value of "1" for controlling the damping force is output to the drive transistor 34a, and the damping force variable shock absorber 6a is returned to the low damping force.

Thereafter, the interrupt process is ended and the main program is returned to, and this damping force control state is repeated every time the interrupt process is executed, and continues until the damping force is no longer applied.

Also, from this damping force control state, when the relative displacement detection value Xa between the cylinder tube, the tube 7, and the piston wand 8 moves downward from the neutral position RXw (when it reaches 3, the amount of change formed by the differential value of the relative displacement Since the value Xa is Xa≧a,
The process moves from step (2) to step (2) through steps (2) to (2), where the control flag F is set to "1", and then the process moves to step (2), where it is determined whether the peak value has been reached. At this time, in a state where the change ffk Xa is in the region where it acts as an excitation force on the vehicle body before the peak value, the change ffk Control the damping force. As a result, it is possible to absorb vibration components acting on the vehicle body in the excitation direction and prevent vertical vibration of the vehicle body.

Similarly, when the transmission force transmitted to the vehicle body acts in the damping direction, the variable damping force shock absorber 6i is set to a high damping force, and when the force transmitted to the vehicle body acts in the vibration direction, the variable damping force shock absorber 61 is set to a low damping force. control to prevent changes in vehicle body posture.

Further, when the vehicle is driven on a rough road such as an undulating paved road or a gravel road from the bottoming processing state described above, the relative displacement position Xi of the variable damping force shock absorber 61 is changed to the first
As shown in Figure 0 (a), the peak values on the elongation side and the contraction side are repeated at short intervals.

In this way, when the peak value frequently occurs, each time the relative displacement change amount X reaches a peak value of approximately zero, the process moves through steps ■ to step ■ to step ■.
Shifting from this step ■ to step ■, the period To from the previous peak value to the current peak value is measured with a counter, etc., and the measured value Tn and the past three times stored in the storage device are measured.
The average cycle Txi is calculated by averaging the three measured values Tn-1, Tn-2, and Tn-3, and is stored in a predetermined storage area of the storage device.

Next, in step [phase], 2 of the average period Tx is calculated as the preset value TM of the timed timer, this precent value TM is preset to the timed timer in step 0, and the control flag F is set to "O" in step @. ” and then move to step [phase]. Therefore, in step 0, the variable damping force shock absorber 6a is controlled to a high damping force, and this high damping force state continues until the timer times out.

In this way, if the period between peak values is detected and the preset value TM of the timer that continues the high damping force is changed accordingly, the high damping force on the damping side of the transmission force transmitted to the vehicle body can be changed accordingly. The damping force state is not unnecessarily continued to the excitation side state, and changes in the attitude of the vehicle body can be reliably suppressed.

When the power spectrum of the relative displacement during driving on this rough road was actually measured, a characteristic curve L5 shown by the solid line in Fig. 12(a) was obtained, and a remarkable control effect was obtained compared to the low damping force fixed control shown by the dotted line. be able to.

Also, the actual measured value of the power spectrum of the transmitted force is shown in Figure 12 (b)! This is represented by a characteristic curve L6 shown by a solid line, and a superior control effect can be obtained compared to the high damping force fixed control shown by a dotted line.

In this rough road driving condition, as shown in the enlarged view in FIG. is controlled to a high damping force, and the variable damping force shock absorber 61 is similarly maintained at a high damping force at the lower peak time tn+1 when shifting to the next excitation side, but when the relative displacement 1x is at the neutral position When the excitation side moves to the contraction side beyond Therefore, it does not significantly affect the vibration damping effect.

Further, in the above description, a case has been described in which only the wheel 5a passes through an uneven road surface, but when the other wheels 5b to 5d pass through an uneven road surface, the variable damping force shock absorbers 6b to 6d are controlled in the same manner as described above. be done.

According to the above embodiment, when the detected relative displacement value Xi between the cylinder tube 7 and the piston wand 8 changes in the excitation direction away from the neutral position amount displacement XN accompanied by a change in attitude with respect to the vehicle body, the damping force variable shock absorber 61
By reducing the damping force of When the vehicle moves in the direction toward the neutral position displacement ffl It is possible to reduce the displacement on the fly, which indicates a change in posture.

Incidentally, when the above-mentioned control according to the present invention is not performed, the change in the posture of the vehicle when the wheel engages with a concave portion of the road surface will be as shown in FIG. 9 ( As shown by the dotted curve L2 in d), it is possible to shorten the vibration damping time and achieve a large damping effect, but the degree to which road surface input is transmitted to the vehicle body increases, resulting in a large sprung mass displacement. Therefore, the vertical acceleration at the vehicle floor also increases, giving the occupants a feeling of bumpy vehicle body vibration, resulting in poor ride comfort. In addition, variable damping force shift absorbers 6a to 6
When the damping force of d is reduced, the force transmitted to the vehicle body becomes smaller, as shown by the curve L'A L 3 indicated by the chain line in Fig. 9(d), but the damping effect is reduced, and the There was a problem in that the vibration damping time became long and the riding comfort worsened as described above.

However, according to the present invention, as described above, the force F transmitted to the vehicle can be extremely reduced as shown in FIG. According to the above embodiment, the damping force is controlled by controlling the electromagnetic solenoid of the variable damping force shock absorber on/off. This has the advantage that the parts have excellent durability and can be constructed at low cost.

In addition, in the above embodiment, the displacement amount detection means 2a to 2
d, the case where the detection coil is used to detect the relative displacement between the cylinder tube 7 and the piston rod 8 has been described, but the present invention is not limited to this. A piezoelectric element 42 is inserted into a mounting portion 41 of the variable damping force shock absorber 6a to 6d, which is connected to the vehicle body side member 40 at the tip of the piston rod 8.
Accordingly, the displacement amount detection signal shown in FIG. 14(b) may be obtained, which is a voltage corresponding to the relative displacement 1x shown in FIG. 14(a) of the variable damping force shock absorbers 6a to 6d. In this case, the peak point of the relative displacement amount X and the point of time when the displacement amount detection signal of the piezoelectric element 42 crosses zero are equal, so by detecting this point of time, the peak point of the relative displacement 1x can be detected. This makes it possible to prevent changes in the attitude of the vehicle as in the above embodiments. Furthermore, since the force transmitted to the vehicle body is directly detected using a piezoelectric element, there is less response delay than when detecting relative displacement, and accurate allocation control can be performed, resulting in excellent ride comfort. In addition, since the piezoelectric element 42 is used as the detection element, it has the advantage of being easy to assemble and being able to be constructed at low cost.

In addition, in FIG. 13, 43 is a coil spring;
4.45 is a spring seat, and 46 is a mount insulator.

In addition, as other displacement detection means, it is possible to apply a displacement detection means such as a distance measuring device that measures the distance between the road surface and the vehicle body using sound waves provided at each wheel position of the vehicle body. can.

Furthermore, the variable damping force shock absorbers 6a to 6d are not limited to the above configurations (as long as they have a configuration that allows the damping force to be changed by inputting a control signal).
Any variable damping force shock absorber may be applied.

Furthermore, the control device 3 is not limited to the above-mentioned configuration, and may be configured with an electronic circuit such as a subtraction circuit, a comparison circuit, a logic circuit, etc. It is also possible to continuously change the damping force of the variable damping force shock absorbers 6a to 6d in accordance with the transmitted force by variously changing the values or by outputting pulse outputs with different duty ratios.

〔Effect of the invention〕

As explained above, according to the present invention, by detecting the peak points on the bounce side and rebound side of the transmission force transmitted from the road surface to the vehicle body via the suspension with the peak point detection means, the vibration damping side for the vehicle body is detected. , and based on the detection result, the control means controls the variable damping force shock absorber to high damping force for a predetermined time and to low damping force at other times, so that the damping force is not transmitted to the vehicle body. It is possible to increase the damping energy in relation to the excitation energy, which quickly suppresses vehicle body vibration (
In addition to ensuring a comfortable ride, there is little vibration on bumps due to uneven road surfaces, and the ground contact of the wheels can be improved, resulting in the effect that maneuverability can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram showing an overview of this invention, FIG. 2 is a block diagram showing an embodiment of this invention, FIG. 3 is a configuration diagram showing a schematic configuration of this invention, and FIG. A sectional view showing an example of an applicable variable damping force shock absorber,
Fig. 5 is a characteristic curve diagram showing the damping force characteristics, Fig. 6 is a block diagram showing an example of the displacement detection means, Fig. 7 is a graph showing the relationship between the output voltage and the relative displacement, and Fig. 8 is the control 9 to 11 are signal waveform diagrams to provide a detailed explanation of the present invention, and FIGS. 12(a) and 12(bl) show the relationship between frequency and power spectrum of relative displacement, respectively. A graph showing the relationship between the frequency and the power spectrum of the transmitted force, FIG. 13 is a sectional view showing another embodiment of the displacement amount detection means, and FIG. 14 is a waveform diagram showing the relationship between the output voltage and the relative displacement amount. 1...Vehicle speed detector, 2a-2d...Displacement amount detection means, 3...Control device, 4a-4d.
...Electromagnetic solenoid, 5a to 5d...Wheel, 6a to 6d...Variable damping force shock absorber, 7...Cylinder tube, 8...
...Piston rod, 11.13...Fluid passage, 14...Through hole, 15 Spool, 17...
...During plunge, 21...Displacement■Detection coil,
22... LC oscillator, 23... Frequency-voltage conversion circuit, 30... Microcomputer, 32... Multiplexer, 33...
- A/D converter, 34a to 34d...drive transistor, 42...piezoelectric element.

Claims (4)

[Claims] (1) In a vehicle shock absorber control device that controls a shock absorber whose damping force can be changed by inputting a control signal, a displacement or transmission force detection means for detecting the displacement or transmission force of the shock absorber, and the displacement amount or peak point detection means for detecting peak points on the extension side and contraction side of the shock absorber based on the detection signal of the transmission force detection means, and a damping force of the shock absorber for a predetermined period of time based on the detection signal of the peak point detection means. or a control means for increasing a spring constant. (2) The shock absorber control device for a vehicle according to claim (1), wherein the control means sets the predetermined time to a period of 1/4 of the sprung mass resonance frequency or pitching frequency of the vehicle. . (3) The control means has a function of determining whether the displacement amount of the detection signal from the displacement amount detection means is within a predetermined threshold value, and outputs the control signal only when the displacement amount is outside the predetermined threshold value. A shock absorber control device for a vehicle as set forth in claim (1) or (2). (4) The vehicle shock according to any one of claims (1) to (3), wherein the control means is configured to change the predetermined time according to the peak value frequency. Absorber control device.