JP3127823B2 - Vehicle damping force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a damping force control device for a vehicle, and more particularly, to a damping force control device capable of effectively suppressing pitching and rolling of a vehicle body.

[0002]

2. Description of the Related Art As one of damping force control devices for vehicles such as automobiles, as described in, for example, Japanese Patent Application Laid-Open No. 4-201710, a difference in passage time between a front wheel and a rear wheel is calculated based on a vehicle speed. The damping force of the front wheel side suspension is controlled based on the vertical acceleration on the side spring, etc., and the difference between the damping force required to obtain the optimal control force in the front wheel side suspension and the actually generated damping force A damping force control device is known which is configured such that a correction value corresponding to the following formula is obtained, and the damping force of the rear wheel side suspension is controlled based on the vertical acceleration on the rear wheel side spring and the correction value. .

[0003] As one of the simple damping force control devices,
The transit time difference between the front wheel and the rear wheel is calculated based on the vehicle speed, the damping force of the front wheel suspension is controlled based on the vertical acceleration on the front wheel spring, etc., and the damping force of the rear wheel suspension is the transit time difference. A damping force control device that is controlled to be equal to the damping force of the side suspension is already known.

According to the above-described damping force control device, the vibration of the rear wheel side can be effectively attenuated by preventing the damping force of the rear wheel side suspension from becoming insufficient. According to the damping force control device, the damping force control device can be configured at a lower cost as compared with the case where a vertical acceleration sensor or the like is provided for each wheel.

[0005]

However, the body of the rear wheel does not always vibrate in the same manner as the vibration of the body of the front wheel when the passage time between the front wheel and the rear wheel elapses. In particular, when the vehicle body is accompanied by pitch vibration or roll vibration, the vibration of the vehicle body cannot always be effectively attenuated by the above-described conventional damping force control device.

[0006] The inventor of the present application has conducted various experimental studies to solve such a problem. As a result, when the vehicle body is subject to pitch vibration, the damping force of the rear wheel side suspension is calculated based on the transit time difference between the front and rear wheels. By controlling early, the vibration of the vehicle body can be effectively attenuated, and when the vehicle body involves roll vibration, the damping force of the front wheel side and the rear wheel side suspension is simultaneously controlled without time delay, It has been found that vibration can be effectively damped.

Also, the inventor of the present application has found that the variation of the rear wheel speed with respect to the reference wheel speed based on the vehicle speed is an excellent index for the pitch vibration of the vehicle body. The degree of the pitch vibration of the vehicle body can be known from the magnitude of the fluctuation amount, and when the vehicle body rolls, the difference between the fluctuation amounts of the wheel speeds of the left and right front wheels increases. It has been found that it is possible to know whether or not it has occurred and to what extent.

The present invention has been made in view of the above-described problems in a conventional damping force control device configured to control the damping force of a rear wheel side suspension based on a difference in passage time between a front wheel and a rear wheel. The main problem of the present invention is
By judging whether or not the vehicle body is vibrating with pitch vibration or roll vibration, and optimizing the control timing of the damping force of the rear wheel side suspension based on the determination result, the vehicle body can reduce pitch vibration or roll vibration. The object is to effectively attenuate the vibration of the vehicle body even when it vibrates with it.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a vehicle for detecting a sprung speed on a front wheel side of a vehicle, a vehicle speed detecting means, and a vehicle speed detecting device based on the sprung speed. Means for controlling the damping force of the front wheel side suspension, means for calculating the delay time of the damping force control of the rear wheel side suspension with respect to the damping force control of the front wheel side suspension based on the vehicle speed and the wheelbase of the vehicle, Means for controlling a damping force of a rear wheel suspension based on the delay time, wherein a means for detecting a wheel speed; and a means for detecting a wheel speed of a rear wheel with respect to a reference wheel speed based on the vehicle speed. A damping force control system for a vehicle, comprising: means for calculating a fluctuation amount; and means for correcting the delay time so that the delay time becomes shorter as the fluctuation amount of the rear wheel speed increases. A device for detecting a sprung speed on the front wheel side of the vehicle, a vehicle speed detecting means, a means for controlling a damping force of a front wheel suspension based on the sprung speed, and a vehicle speed. Means for calculating a delay time of the damping force control of the rear wheel side suspension with respect to the damping force control of the front wheel side suspension based on the wheel base of the vehicle; and Means for detecting wheel speed, means for calculating the amount of change in the wheel speed of the left and right front wheels with respect to a reference wheel speed based on the vehicle speed, and means for controlling the wheels of the left and right front wheels Means for correcting the delay time to substantially zero when the difference between the speed fluctuations exceeds the reference value. It is achieved Te.

According to the first aspect of the present invention, the amount of change in the rear wheel speed with respect to the reference wheel speed based on the vehicle speed is calculated, and the larger the amount of change in the rear wheel speed, the shorter the delay time becomes. Since the time is corrected, the larger the fluctuation amount of the rear wheel speed, the faster the damping force of the rear wheel suspension is controlled, so that even when the vehicle body vibrates in pitch, the vehicle body vibration on the rear wheel side is effectively reduced. Attenuated.

According to the second aspect of the present invention, the amount of change in the wheel speed of the left and right front wheels with respect to the reference wheel speed based on the vehicle speed is calculated. Is substantially corrected to 0,
The damping force of the left and right rear wheel suspensions is controlled substantially simultaneously with the damping force of the left and right front wheel suspensions, so that even when the vehicle body rolls, the vehicle body vibration on the rear wheel side is effectively attenuated.

[0012]

According to a preferred aspect of the present invention, there is provided the above-mentioned claim 1 or 2,
The means for controlling the damping force of the front wheel suspension based on the sprung speed is configured to control the damping force of the front wheel suspension in accordance with the Skyhook theory based on the sprung speed and the relative speed between the sprung and the unsprung. .

According to one preferred aspect of the present invention, in the configuration of the first or second aspect, the means for controlling the damping force of the rear wheel side suspension is such that the damping coefficient of the rear wheel side suspension is shorter than the delay time. It is configured to control the damping coefficient of the rear wheel side suspension so as to become the damping coefficient of the front wheel side suspension.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to the accompanying drawings, in which several preferred embodiments are shown.

FIG. 1 is a schematic configuration diagram showing a first embodiment of a vehicle damping force control device according to the present invention.

In FIG. 1, 10fl, 10fr, 10rl,
10rr indicates a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel, respectively. Shock absorbers 12fl, 12fr, 12rl, and 12rr are provided at positions corresponding to these wheels, respectively. 12fl-1
The damping force of 2rr corresponds to the corresponding actuator 14f
Electric control device 1 via l, 14fr, 14rl, 14rr
6 is controlled.

A vehicle height sensor 18fl and a vertical acceleration sensor 20fl are provided at a position corresponding to the front left wheel 10fl, and the vehicle height sensor 18fl detects the vehicle height Hfl of the front left wheel.
The vertical acceleration sensor 20fl detects a sprung acceleration Gzfl of the left front wheel 10fl. Also, left front wheel 10fl and left rear wheel 10rl
Are the wheel speeds Vwfl and Vwrl of the corresponding wheels, respectively.
Are provided.

Vehicle height sensor 18 fl and vertical acceleration sensor 2
Signals indicating the vehicle height Hfl of the left front wheel and the sprung acceleration Gzfl of the left front wheel detected by 0fl are not shown in the figure.
A / D converter and low-pass filters 24 fl and 26 fl are supplied to the electric control device 16 and the wheel speed sensor 22
The signals indicating the wheel speeds Vwfl and Vwrl of the left front wheel 10fl and the left rear wheel 10rl detected by fl and 22rl pass through band-pass filters 28fl and 30rl, respectively, and the electric controller 1
6. A signal indicating the vehicle speed V detected by the vehicle speed sensor 32 is input to the electric control device 16.

The electric control unit 16 determines the vehicle height Hfl of the front left wheel.
To calculate the stroke speed Vyfl of the left front wheel shock absorber by differentiating, and calculate the sprung speed Vzfl by integrating the vertical acceleration Gzfl of the vehicle body of the left front wheel to control the damping force of the left and right rear wheel shock absorbers. To calculate the delay time Δt.

The electric control unit 16 calculates a target control stage Saf of the left and right front wheel shock absorbers based on the stroke speed Vyfl and the sprung speed Vzfl, as described later.
A control signal for setting the control stage to the target control stage Saf is output to the actuators 14fl and 14fr, whereby the control stages of the left and right front wheel shock absorbers are controlled to the target control stages, and the target of the left and right rear wheel shock absorbers is set. Control stage S
ar is set to the control stage of the left and right front wheel shock absorbers that goes back by the delay time Δt, and a control signal for setting the control stage to the target control stage Sar is output to the actuators 14rl and 14rr, whereby the left and right rear wheel shock absorbers are controlled. The control stage is controlled to the target control stage.

Note that the electric control device 16 is actually, for example, C
It may be constituted by a microcomputer having one well-known configuration including a PU, a ROM, a RAM, and an input / output device and a drive circuit.

Next, a damping force control routine of the shock absorber according to the first embodiment will be described with reference to a flowchart shown in FIG.

In step 10, a vehicle height sensor 18 fl
Then, a signal indicating the vehicle height Hfl of the left front wheel detected is read, and in step 20, the target control stage Saf of the left and right front wheel shock absorbers is calculated in accordance with the routine shown in FIG. In this case, the control signals for setting the control stages of the left and right front shock absorbers to the target control stage Saf are transmitted to the actuators 14fl and 14fr.
The control stage of the left and right front wheel shock absorbers is controlled to the target control stage.

In step 40, the variation amounts ΔVpf and ΔVpr of the wheel speeds of the left front wheel and the left rear wheel with respect to the reference wheel speed Vwe based on the vehicle speed V in accordance with the routine shown in FIG.
It is determined in step 50 whether the vehicle speed V exceeds the control reference value Vo. If a negative determination is made, the process proceeds to step 90; if an affirmative determination is made, the process proceeds to step 90. Proceed to 60.

In step 60, it is determined whether or not the variation ΔVpr of the wheel speed of the left rear wheel is greater than the variation ΔVpf of the wheel speed of the front left wheel. If a negative determination is made, the process proceeds to step 90. When the determination is affirmative, the correction value α of the delay time Δt is calculated from the map corresponding to the graph shown in FIG.

In step 80, the delay time Δt is calculated according to the following equation (1), and in step 90, the delay time Δt is calculated according to the following equation (2).

Δt = (L / V) −α

## EQU2 ## Δt = L / V

In step 100, the target control stage Saf of the left and right front wheel shock absorbers before Δt is set to the target control stage Sar of the left and right rear wheel shock absorbers. In step 110, the left and right rear wheel shock absorbers are set. Is output to the actuators 14rl and 14rr, whereby the control stages of the left and right rear wheel shock absorbers are controlled to the target control stages.

In step 21 of the target control stage Saf calculation routine for the left and right front wheel shock absorbers shown in FIG. 3, the stroke speed Vyfl of the left front wheel shock absorber is calculated by differentiating the vehicle height Hfl of the left front wheel. In step 22, the sprung speed Vzfl is calculated by integrating the vertical acceleration Gzfl of the vehicle body of the left front wheel.

In step 23, the calculation of the skyhook is performed according to the following equation 3 based on the stroke speed Vyfl and the sprung speed Vzfl using Cs as the skyhook damping coefficient, so that the shock absorbers 12fl and 12fr of the left and right front wheels are obtained. The required attenuation coefficient Creqf is calculated, and in step 24, it is determined whether or not the attenuation coefficient Creqf is negative. If a negative determination is made, the process directly proceeds to step 26, and an affirmative determination is made. In step 25, the damping coefficient Creqf is set to 0 in step 25.

## EQU3 ## Creqf = Cs × (Vzfl / Vyfl)

In step 26, the damping coefficient Caf closest to the damping coefficient Creqf is selected from the damping coefficients corresponding to the respective control stages of the left and right front wheel shock absorbers, and the control of the shock absorber corresponding to the selected damping coefficient is performed. The stage is set as the target control stage Saf.

In step 41 of the routine for calculating the wheel speed fluctuations ΔVpf and ΔVpr of the front left wheel and the rear left wheel shown in FIG. 4, the wheel speed corresponding to the vehicle speed V is changed to the reference wheel speed Vwe based on the vehicle speed V. In step 42, the deviation Δ of the wheel speed of the left front wheel is calculated according to the following equation (4).
Vwfl is calculated, and in step 43, the following equation 5 is obtained.
, The deviation ΔVwfr of the wheel speed of the left rear wheel is calculated.

[0032]

[Expression 4] ΔVwfl = Vwfl−Vwe

５Vwrl = Vwrl−Vwe

At step 44, as shown in the upper part of FIG. 6, the maximum value ΔVwflmax and the minimum value ΔVwflmin of the deviation ΔVwfl of the wheel speed of the left front wheel within a predetermined time Te from the present time are obtained. The variation ΔVpf of the wheel speed of the front left wheel is calculated according to the following equation (6).

(6) ΔVpf = ΔVwflmax−ΔVwflmin

Similarly, in step 45, as shown in the lower part of FIG. 6, the maximum value ΔVwrlmax of the deviation ΔVwrl of the wheel speed of the left rear wheel within a predetermined time Te from the present time.
And the minimum value ΔVwrlmin is obtained, and
Is calculated in accordance with the following equation.

(7) ΔVpr = ΔVwrlmax−ΔVwrlmin

Thus, according to the illustrated first embodiment,
When the fluctuation amount ΔVpr of the wheel speed of the left rear wheel is equal to or less than the fluctuation amount ΔVpf of the wheel speed of the front left wheel, a negative determination is made in step 60, and the delay time Δt is determined in step 90 in accordance with Equation 2. Is calculated. Even if the fluctuation amount ΔVpr of the wheel speed of the left rear wheel exceeds the fluctuation amount ΔVpf of the wheel speed of the front left wheel, the fluctuation amount ΔV
When pr is equal to or smaller than the reference value ΔVpo in FIG. 5, the correction value α is set to 0 in step 70, and the delay time Δt is calculated in step 80 according to the same equation as in equation (2).

Therefore, in these cases, the shock absorbers of the left and right rear wheels are controlled to the same control stages as the control stages of the left and right front wheel shock absorbers before the delay time Δt determined by the wheel base L and the vehicle speed V of the vehicle. Even when the vehicle travels on a undulating road surface, the vibration of the vehicle body on the rear wheel side can be effectively attenuated.

If the vertical vibration of the vehicle body on the rear wheel side becomes large and the fluctuation amount ΔVpr of the wheel speed of the left rear wheel becomes larger than the fluctuation amount Vpf of the wheel speed of the front left wheel, an affirmative determination is made in step 60. In step 70, the correction value α
Is calculated to be a positive value, and the delay time Δt is calculated according to Equation 1 in step 80. As a result, the delay time Δt becomes smaller than the delay time determined by the wheel base L and the vehicle speed V of the vehicle. By controlling the damping force of the shock absorber earlier, the vibration of the vehicle body on the rear wheel side is effectively attenuated, whereby the pitch vibration of the vehicle body can be effectively attenuated.

In particular, according to the illustrated embodiment, step 6
At 0, it is determined whether or not the fluctuation amount ΔVpr of the wheel speed of the left rear wheel is greater than the fluctuation amount ΔVpf of the wheel speed of the front left wheel. Step 70 is executed only when the affirmative determination is made. Therefore, the vibration is effectively damped by controlling the damping force based on the skyhook theory. The rear wheel side body vibration when the rear wheel side relatively moves up and down relatively to the front wheel side is effective. Can be attenuated.

FIG. 7 is a schematic diagram showing a second embodiment of a vehicle damping force control device according to the present invention. In FIG. 7, the same members as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG.

In this embodiment, the vehicle height sensor 18
The fl and the vertical acceleration sensor 20fl are provided corresponding to the left front wheel 10fl as in the first embodiment, but the wheel speeds Vwfl and Vwfr of the wheels respectively corresponding to the left front wheel 10fl and the right front wheel 10fr are provided as wheel speed sensors. Wheel speed sensors 22fl and 22fr for detecting are provided.

The wheel speed Vwf of the left front wheel 10fl and the right front wheel 10fr detected by the wheel speed sensors 22fl and 22fr.
The signals indicating l and Vwfr are supplied to the electric controller 16 via band-pass filters 28fl and 30fr. A signal indicating the steering angle θ is input from the steering angle sensor 34 to the electric control device 16.

Next, a routine for controlling the damping force of the shock absorber in the second embodiment will be described with reference to the flowchart shown in FIG. Note that FIG.
2 are given the same step numbers as those given in FIG.

In step 10, the vehicle height sensor 18fl
Then, a signal indicating the vehicle height Hfl of the left front wheel detected is read, and in step 20, the target control stage Saf of the left and right front wheel shock absorbers is calculated in accordance with the routine shown in FIG. In this case, the control signals for setting the control stages of the left and right front shock absorbers to the target control stage Saf are transmitted to the actuators 14fl and 14fr.
The control stage of the left and right front wheel shock absorbers is controlled to the target control stage.

In step 40, the variation amounts of the wheel speeds of the left front wheel and the right front wheel with respect to the reference wheel speed Vwe based on the vehicle speed V in accordance with the routine shown in FIG.
pfr is calculated, and in step 50, it is determined whether or not the vehicle speed V exceeds the control reference value Vo. If a negative determination is made, the process proceeds to step 90, and if an affirmative determination is made, Proceed to step 65.

In step 65, it is determined whether or not the vehicle is turning based on the steering angle θ. If the determination is affirmative, the process proceeds to step 90; if the determination is negative, step 75 is performed. At step 90, it is determined whether or not the absolute value of the variation amount .DELTA.Vpfl-.DELTA.Vpfr of the wheel speeds of the left front wheel and the right front wheel exceeds a reference value .beta. (Positive constant). The process proceeds to step 85 when the affirmative determination is made. Step 8
In step 5, the delay time Δt is set to 0, and step 9
At 0, the delay time Δt is calculated according to the above equation (2).

In step 100, the target control stage Saf of the left and right front wheel shock absorbers before Δt is set to the target control stage Sar of the left and right rear wheel shock absorbers. In step 110, the left and right rear wheel shock absorbers are set. Is output to the actuators 14rl and 14rr, whereby the control stages of the left and right rear wheel shock absorbers are controlled to the target control stages.

In step 41 of the routine for calculating the wheel speed fluctuations ΔVpfl and ΔVpfr of the front left wheel and the front right wheel shown in FIG. 9, the wheel speed corresponding to the vehicle speed V is calculated as the reference wheel speed Vwe based on the vehicle speed V. In step 42, the deviation ΔV of the wheel speed of the left front wheel is calculated according to the above equation (4).
wfl is calculated, and in step 46, a deviation ΔVwfr of the wheel speed of the right front wheel is calculated according to the following equation (8).

ΔVwfr = Vwfr−Vwe

In step 47, as shown in the upper part of FIG. 10, the absolute value of the deviation ΔVwfl of the wheel speed of the left front wheel within a predetermined time Te from the present time is the wheel speed of the left front wheel. In step 48, as shown in the lower part of FIG. 10, the maximum value of the absolute value of the deviation ΔVwfr of the wheel speed of the right front wheel within the predetermined time Te from the present time is calculated as shown in the lower part of FIG. It is calculated as the fluctuation amount ΔVpfr of the wheel speed of the right front wheel.

Thus, according to the illustrated second embodiment,
When the magnitude of the difference ΔVpfl−ΔVpfr between the fluctuation amounts of the wheel speeds of the left and right front wheels is equal to or smaller than the reference value β, a negative determination is made in step 75, so that the delay time Δt is calculated according to equation 2. Therefore, in this case, as in the first embodiment, the left and right rear wheel shock absorbers have the same control as the control stages of the left and right front wheel shock absorbers before the delay time Δt determined by the wheel base L and the vehicle speed V of the vehicle. Since the vehicle is controlled in steps, the vibration of the vehicle body on the rear wheel side can be effectively attenuated even when the vehicle travels on a undulating road surface.

If the difference between the wheel speed fluctuations of the left and right front wheels exceeds the reference value, an affirmative determination is made in step 75 and the delay time Δt is set to 0 in step 85. The shock absorbers for the left and right rear wheels are controlled to the same control stage simultaneously with the shock absorbers for the left and right front wheels, so that the roll vibration of the vehicle body can be effectively attenuated.

In particular, according to the illustrated embodiment, step 6
In 5 it is determined whether the vehicle is turning or not,
Step 90 is executed when the vehicle is turning, so that the vibration of the vehicle body on the rear wheel side when the vehicle turns on a undulating road surface can be effectively attenuated.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments may be included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the above embodiments, the damping force of the front wheel suspension is controlled based on the skyhook theory, but the damping force of the front wheel suspension is controlled according to an arbitrary control law. May be.

Further, the first embodiment and the second embodiment described above may be combined so that both pitch vibration and roll vibration of the vehicle body are effectively attenuated.
Step 60 in the first embodiment or step 65 in the second embodiment may be omitted.

Further, in each of the above embodiments, the damping force of the suspensions on the front wheel side and the rear wheel side is generated by the shock absorber. , The damping force of the suspension may be increased or decreased by increasing or decreasing the pressure of the hydraulic cylinder.

[0056]

As is apparent from the above description, according to the first aspect of the present invention, the variation of the rear wheel speed with respect to the reference wheel speed based on the vehicle speed is calculated, and the rear wheel speed is calculated. Since the delay time is corrected so that the delay time becomes shorter as the fluctuation amount of the rear wheel is larger, the damping force of the rear wheel side suspension is controlled faster as the fluctuation amount of the rear wheel speed is larger,
This makes it possible to effectively attenuate the vibration of the vehicle body even when the vehicle body vibrates in pitch, and to reduce the cost of the damping force control device as compared with the case where a sensor for detecting the sprung speed or the like is provided for each wheel. And a simple structure can be obtained.

According to the second aspect of the present invention, the amount of change in the wheel speed of the left and right front wheels with respect to the reference wheel speed based on the vehicle speed is calculated. Is substantially corrected to 0,
The damping force of the left and right rear wheel suspensions is controlled substantially simultaneously with the damping force of the left and right front wheel suspensions, thereby effectively damping the vehicle body vibration even when the vehicle body rolls. As compared with the case where a sensor for detecting a sprung speed or the like is provided every time, the damping force control device can be made inexpensive and have a simple structure.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a vehicle damping force control device according to the present invention.

FIG. 2 is a flowchart illustrating a damping force control routine of a shock absorber according to the first embodiment.

FIG. 3 is a step 20 of the flowchart shown in FIG. 2;
3 is a flowchart showing a target control stage Sa calculation routine in FIG.

FIG. 4 is a step 40 of the flowchart shown in FIG. 2;
Of the wheel speed of the left front wheel and the left rear wheel at the time ΔVpf,
9 is a flowchart illustrating a ΔVpr calculation routine.

FIG. 5 is a graph showing a relationship between a fluctuation amount ΔVpr of a wheel speed of a left rear wheel and a correction value α of a delay time.

FIG. 6 shows a variation ΔVpf of a wheel speed of a left front wheel and a left rear wheel,
6 is a graph showing a calculation procedure of ΔVpr.

FIG. 7 is a schematic configuration diagram showing a second embodiment of a vehicle damping force control device according to the present invention.

FIG. 8 is a flowchart illustrating a damping force control routine of a shock absorber according to a second embodiment.

FIG. 9 is a step 40 in the flowchart shown in FIG. 7;
Of the wheel speeds of the left and right front wheels ΔVpfl, ΔVpf
9 is a flowchart illustrating an r calculation routine.

FIG. 10 shows the variation amounts ΔVpfl, ΔV of the wheel speeds of the left and right front wheels.
6 is a graph showing a calculation procedure of pfr.

[Explanation of symbols]

 12 fl-12 rr Shock absorber 16 Electric controller 18 fl Vehicle height sensor 20 fl Vertical acceleration sensor 22 fl, 22 fr, 22 rl Wheel speed sensor 32 Vehicle speed sensor 34 Steering angle sensor

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60G 1/00-25/00

Claims (2)

(57) [Claims] 1. A means for detecting a sprung speed on a front wheel side of a vehicle, a vehicle speed detecting means, a means for controlling a damping force of a front wheel side suspension based on the sprung speed, a vehicle speed and a wheel base of the vehicle. Means for calculating a delay time of the damping force control of the rear wheel suspension with respect to the damping force control of the front wheel side suspension, and means for controlling the damping force of the rear wheel suspension based on the sprung speed and the delay time. In a damping force control device for a vehicle having
Means for detecting wheel speed, means for calculating the amount of change in wheel speed of the rear wheel with respect to a reference wheel speed based on the vehicle speed, and the delay such that the larger the amount of change in wheel speed of the rear wheel, the shorter the delay time becomes. A damping force control device for a vehicle, comprising: means for correcting time. 2. A means for detecting a sprung speed on a front wheel side of a vehicle, a vehicle speed detecting means, a means for controlling a damping force of a front wheel side suspension based on the sprung speed, a vehicle speed and a wheel base of the vehicle. Means for calculating a delay time of the damping force control of the rear wheel suspension with respect to the damping force control of the front wheel side suspension, and means for controlling the damping force of the rear wheel suspension based on the sprung speed and the delay time. In a damping force control device for a vehicle having
Means for detecting the wheel speed, means for calculating the amount of change in the wheel speed of the left and right front wheels with respect to the reference wheel speed based on the vehicle speed,
Means for correcting the delay time to substantially zero when the difference between the wheel speed fluctuations of the left and right front wheels exceeds a reference value.