JPH0624224A - Car suspension device - Google Patents

Abstract

PURPOSE:To generate vibration isolation of good performance for the moment of inertia without degrading the comfort in a car cabin in response to the input from road surface by furnishing a pitch correcting part and a roll correcting part or a control means which includes a damping coefficient control part. CONSTITUTION:When the super-spring vertical movement (bouncing), pitching, and rolling are sensed by super-spring vertical velocity sensing means (c), pitch rate sensing means (d), and roll rate sensing means (e), a control signal is determined by a damping coefficient control part (h) on the basis of the super-spring vertical velocity, pitch rate, and roll rate, and the damping coefficient of a shock absorber (b) is controlled in conformity to the control signal determined. When the car is in rapidly accelerating or decelerating state, the pitch rate is amplified by a pitch correction part (k), and when the car is in the specified steering condition, the roll rate is amplified by a roll correction part (m).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension system for optimally controlling a damping coefficient of a shock absorber.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension system for controlling a damping coefficient of a shock absorber, for example, Japanese Patent Laid-Open No. 61-
The one described in Japanese Patent No. 163011 is known.
This conventional vehicle suspension system detects the sprung vertical speed and the relative speed between the sprung and unsprung parts, and when both have the same sign, the damping coefficient is made hard, and when the two have different signs, the damping coefficient is made soft. The damping coefficient control such as the above is performed independently for the four wheels.

[0003]

However, in the conventional device having the above-mentioned structure, when the characteristic of the hardware is suitable for the case where the vehicle body is moving in the bounce direction, the bounce and the pitching are coupled. For body movements that
Since the vehicle body inertia moment around the center of gravity of the vehicle body is added to the sprung mass, the damping force (control force) is insufficient, steering stability is not sufficient, and the damping force (control force) due to the vehicle body inertia moment is insufficient. If the control gain is set high in order to eliminate the problem, there is a problem that the damping force against the movement of the vehicle body in the bounce direction due to road surface input becomes excessive and the riding comfort of the vehicle deteriorates.

The present invention has been made by paying attention to the above-mentioned conventional problems, and it is possible to obtain a sufficient vibration damping property with respect to the moment of inertia without deteriorating the riding comfort of the vehicle with respect to the road surface input, and thus the steering stability. It is an object of the present invention to provide a vehicle suspension system that can improve

[0005]

Therefore, in the present invention, a control signal is obtained from the sprung vertical velocity, pitch rate, and roll rate, the damping coefficient is controlled based on this control signal, and the vehicle is brought into a sudden acceleration / deceleration state. In some cases, the pitch rate is amplified, and when the vehicle is in a predetermined steering state, the roll rate is amplified, thereby achieving the above object.

That is, the vehicle suspension system according to claim 1 of the present invention is interposed between the vehicle body side and each wheel side, and the damping coefficient is changed by the damping coefficient changing means a, as shown in the claim correspondence diagram of FIG. A possible shock absorber b, a sprung vertical velocity detecting means c for detecting a sprung vertical velocity near a position where each shock absorber b is provided, a pitch rate detecting means d for detecting a pitch rate of a vehicle body, and a vehicle body Roll rate detecting means e for detecting the roll rate of
Rapid acceleration / deceleration state detecting means f for detecting the rapid acceleration / deceleration state of the vehicle
And steering state detecting means g for detecting the steering state of the vehicle,
Control means j having a damping coefficient control unit h for controlling the damping coefficient of each shock absorber b based on the control signal obtained from the sprung vertical velocity, pitch rate and roll rate.
When the vehicle is in a sudden acceleration / deceleration state, the pitch correction section k is provided for amplifying the pitch rate, and when the vehicle is in a predetermined steering state, the pitch correction section k is provided in the control means j.
A roll correction unit m that amplifies the roll rate is provided.

The pitch rate detecting means is means for detecting the pitch rate from the sprung vertical speed difference between the front and rear of the vehicle body based on the sprung vertical speed detected by the sprung vertical speed detecting means. May be means for detecting the roll rate from the difference between the sprung vertical speeds of the right and left of the vehicle body based on the sprung vertical speed detected by the sprung vertical speed detecting means.

In the shock absorber, the expansion side has a variable damping coefficient and the compression side has a low damping coefficient fixed to the expansion side, and the compression side has a variable damping coefficient and the expansion side has a low compression coefficient fixed to the compression side. Both the side and the pressure side are formed in a structure having three regions, a soft region having a low damping coefficient, and the damping coefficient control means sets the shock absorber to the expansion hard region when the control signal is equal to or more than a positive threshold value. The shock absorber is controlled in the pressure side hard area when the control signal is below the negative threshold value, and the shock absorber is controlled in the soft area when the control signal is between the positive and negative threshold values. You may.

Further, in obtaining the control signal,
The sprung vertical velocity uses a signal that has passed through a bandpass filter including the sprung resonance frequencies of the front and rear wheels, the pitch rate uses a signal that has passed through a bandpass filter that includes the pitch resonance frequency, and the roll rate is A band-pass filtered signal containing the roll resonance frequency may be used.

In determining the control signal,
The first proportionality constant for multiplying the sprung vertical direction speed, the second proportionality constant for multiplying the pitch rate, and the third proportionality constant for multiplying the roll rate are independently set, and the first proportionality constant is The value according to the direction spring constant
The proportional constant of 1 may be a numerical value according to the pitch rigidity, and the third proportional constant may be a numerical value according to the roll rigidity.

[0011]

When the sprung speed detecting means, the pitch rate detecting means, and the roll rate detecting means detect the vertical movement (bouncing), pitching, and roll on the spring, the damping coefficient control section determines the sprung vertical speed and pitch. A control signal is obtained based on the rate and the roll rate, and the damping coefficient of the shock absorber is controlled according to the control signal.
When the vehicle is in the rapid acceleration / deceleration state, the pitch correction unit amplifies the pitch rate, and when the vehicle is in the predetermined steering state, the roll correction unit amplifies the roll rate.

Therefore, a sufficient control force for the pitch and roll can be obtained without deteriorating the riding comfort of the vehicle with respect to the road surface input, and the steering stability of the vehicle can be improved.

[0013]

Embodiments of the present invention will be described with reference to the drawings. (First Embodiment) First, the structure will be described.

FIG. 2 is a structural explanatory view showing a vehicle suspension system of a first embodiment, which is an embodiment of the invention described in claims 1, 2, 3, 4, and 5, and is a vehicle body and four wheels. Interposed between the four shock absorbers SA ₁ , SA ₂ , SA
₃ and SA ₄ (in the explanation of the shock absorber, when these 4 are collectively referred to, and when describing their common configuration, they are simply indicated as SA). A vertical acceleration sensor (hereinafter referred to as vertical G sensor) 1 for detecting vertical acceleration is provided on the vehicle body in the vicinity of each shock absorber SA.
Is provided. A steering sensor 2 for detecting a steering angle is provided in the steering ST section.
A control unit 4 is provided near the driver's seat to input a signal from each sensor and output a drive control signal to the pulse motor 3 of each shock absorber SA.

FIG. 3 is a system block diagram showing the above configuration, in which the control unit 4 includes an interface circuit 4a, a CPU 4b, and a drive circuit 4c, and the interface circuit 4a includes the above-described vertical G sensors 1 and A steering sensor 2, a brake sensor 5 for predictively detecting a rapid deceleration state of the vehicle, a fuel pump sensor 6 for predictively detecting a rapid acceleration state of the vehicle by detecting a fuel supply pulse width of a fuel pump, and A signal from the vehicle speed sensor 8 that detects the vehicle speed is input.

In the interface circuit 4a, a set of five filter circuits shown in FIG.
It is provided for each sensor 1. That is, LPF1
In the high frequency range (30
This is a low-pass filter circuit for removing noise above (Hz). LPF2 is a low-pass filter circuit LPF1
Is a low-pass filter circuit for integrating a signal indicating the acceleration that has passed through and converting it into a sprung vertical velocity. BPF
1 is a bounce component signal v (v ₁ , v ₂ , v ₃ , v ₄ by passing a frequency range including the sprung resonance frequency,
The numbers ₁ , ₂ , ₃ , and ₄ correspond to the positions of the shock absorbers SA. The same applies to the following. ) Is a band pass filter circuit that forms The BPF 2 allows the pitch component signal v ′ (v
_{1 ', v 2', v} 3 ', v 4') is a band-pass filter circuit forming the. The BPF 3 allows the roll component signal v ″ (v
₁ ″, v ₂ ″, v ₃ ″, v ₄ ″). Incidentally, in this embodiment, the sprung resonance, the pitch resonance, and the roll resonance frequencies are different from each other. However, when the resonance frequencies are close to each other, only the BPF 1 is required as the bandpass filter.

Next, FIG. 4 is a sectional view showing the structure of the shock absorber SA.
A is a cylinder 30, a piston 31 defining the cylinder 30 into an upper chamber A and a lower chamber B, an outer cylinder 33 having a reservoir chamber 32 formed on the outer periphery of the cylinder 30, a lower chamber B and a reservoir chamber 32. Which defines the base 34 and the piston 32
A guide member 35 that guides the sliding of the piston rod 7 that is connected to the vehicle, a suspension spring 36 that is interposed between the outer cylinder 33 and the vehicle body, and a bumper bar 37.

Next, FIG. 5 is an enlarged sectional view showing a portion of the piston 31. As shown in FIG. 5, the piston 31 is formed with through holes 31a and 31b, and each through hole is formed. An expansion side damping valve 12 and a compression side damping valve 20 that open and close 31a and 31b respectively are provided. In addition, the stud 38 that is fixed to the tip of the piston rod 7 and penetrates the piston 31 has an upper chamber A
Is formed with a communication hole 39 for communicating the lower chamber B with the lower chamber B. Further, an adjuster 40 for changing the flow passage cross-sectional area of the communication hole 39 and a fluid communication hole 39 depending on the direction of fluid flow are formed.
An expansion-side check valve 17 and a pressure-side check valve 22 that allow and block the flow of the air are provided. The adjuster 40 is rotated by the pulse motor 3 (see FIG. 4). In addition, the stud 38 has a first port 21, a second port 13, and a third port in order from the top.
A port 18, a fourth port 14 and a fifth port 16 are formed.

On the other hand, in the adjuster 40, a hollow portion 19 is formed, a first lateral hole 24 and a second lateral hole 25 which communicate the inside and the outside are formed, and a vertical groove 23 is formed in the outer peripheral portion. There is.

Therefore, between the upper chamber A and the lower chamber B, the inside of the extension side damping valve 12 is opened by passing through the through hole 31b as a flow passage through which the fluid can flow in the extension stroke. First side flow path D extending to B, second port 13, vertical groove 2
The expansion side second flow path E which opens the outer peripheral side of the expansion side damping valve 12 to the lower chamber B via the third and fourth ports 14, and the second
The extension side check valve 17 is opened via the port 13, the vertical groove 23, and the fifth port 16 to reach the lower chamber B.
Channel F, third port 18, second lateral hole 25, hollow portion 19
There are four flow paths, a bypass flow path G, which leads to the lower chamber B via. Also, as a flow path through which the fluid can flow in the pressure stroke,
The pressure-side first flow path H that opens the pressure-side damping valve 20 through the through hole 31a and the pressure-side check valve 22 through the hollow portion 19, the first lateral hole 24, and the first port 21 to open the upper chamber A. Pressure side second flow path J leading to the hollow part 19, the second lateral hole 2
5, There are three flow paths, a bypass flow path G reaching the upper chamber A via the third port 18.

That is, the shock absorber SA is constructed so that the damping coefficient can be changed in multiple stages on both the extension side and the compression side with the characteristics shown in FIG. 6 by rotating the adjuster 40. That is, as shown in FIG. 7, both the extension side and the compression side are in the soft state (hereinafter, the soft region S
When the adjuster 40 is rotated counterclockwise from (S), the damping coefficient can be changed in multiple steps only on the expansion side, and the compression side becomes a region where the damping coefficient is fixed to a low damping coefficient (hereinafter referred to as the expansion side hard region HS). On the contrary, when the adjuster 40 is rotated clockwise, the damping coefficient can be changed in multiple steps only on the compression side, and the extension side becomes a region where the low damping coefficient is fixed (hereinafter referred to as the compression side hard region SH). There is.

By the way, in FIG. 7, the KK cross section, the MM cross section, and the NN cross section in FIG. 10 and the damping force characteristics at each position are shown in FIGS.

Next, the operation of the control unit 4 for controlling the drive of the pulse motor 3 will be described with reference to the flowcharts of FIGS. 15 and 16. Note that this control is separately performed for each shock absorber SA.

First, the control flow of the main routine shown in FIG. 15 will be described.

In step 101, the upper and lower G sensors 1,
The vertical acceleration obtained from 1, 1, 1 is applied to each filter circuit L.
This is a step of performing processing by PF1, LPF2, BPF1, BPF2, and BPF3 to obtain a bounce component signal v, a pitch component signal v ′, and a roll component signal v ″, and then proceeds to the subroutine 200.

This subroutine 200 is a routine for obtaining the control signal V, and the control contents will be described later.

Step 102 is a step of judging whether or not the control signal V obtained by the subroutine 200 is equal to or more than a predetermined threshold value δ _{T. If} YES, the process proceeds to step 103, and if NO, the process proceeds to step 104. move on.

Step 103 is a shock absorber S
This is a step of controlling A to the extension side hard area HS.

Step 104 is a step of judging whether or not the control signal V is a value between a predetermined threshold value δ _T and a threshold value −δ _{C. If} YES, then the routine proceeds to step 105, and if NO. Go to step 106.

Step 105 is a shock absorber S
This is a step of controlling A in the soft area SS.

Step 106 is a step displayed for the sake of convenience, and if NO is determined in steps 102 and 105, the control signal V is equal to or lower than a predetermined threshold value -δ _C , and in this case, Go to step 107.

Step 107 is a shock absorber S
This is a step of controlling A to the pressure side hard area SH.

Next, the control flow of the subroutine 200 shown in FIG. 16 will be described.

Step 201 is a step of judging whether or not the brake switch is ON (pitch condition ON) based on the signal from the brake sensor 5. If YES, the routine proceeds to step 202, and if NO, the routine proceeds to step 203.

Step 202 is a step of amplifying the pitch component signal v'when the pitch condition is ON, and then the process proceeds to step 208.

In step 203, the brake switch is turned off.
This is a step of determining whether or not a predetermined time has elapsed after the FF is reached (pitch condition is ON). If NO, the process proceeds to step 202, and if YES, the process proceeds to step 204.

In step 204, based on the signal from the fuel pump sensor 6, the fuel pulse width P of the fuel injection pump for feeding the fuel is equal to or larger than a predetermined threshold value a (pitch condition O.
It is a step of determining whether or not N), and if YES, the process proceeds to step 202, and if NO, the process proceeds to step 205.

Step 205 is a step of determining whether or not a predetermined time has elapsed (pitch condition is ON) after the fuel pulse width P has dropped below the predetermined threshold value a,
NO to proceed to step 202, YES to step 206
Proceed to.

In step 206, the steering angle signal θ from the steering sensor 2 and the steering angular velocity ω calculated from the steering angle signal θ are both predetermined threshold values b based on the steering condition map of FIG. Above (steering condition ON)
Is a step of determining whether or not, and if YES, the process proceeds to step 209, and if NO, the process proceeds to step 207. In the steering condition map, the horizontal axis represents the steering angle θ,
The vertical axis represents the steering angular velocity ω, and as a condition for starting the roll control, the other minimum value corresponding to one of the two values θ and ω is mapped as the threshold value b. There is. The threshold value b is set so as to decrease in inverse proportion to the increase in the vehicle speed detected by the vehicle speed sensor 8.

In step 207, the steering angle signal θ and
This is a step of determining whether or not a predetermined time has elapsed (steering condition is ON) after the steering angular speed ω both decreased below the predetermined threshold value b, and if NO, the process proceeds to step 209,
If YES, the process proceeds to step 208.

Step 208 is a step for judging whether or not the control signal V has become 0 (steering condition OFF) (steering condition ON). If NO, the routine proceeds to step 209, where YE
In S, the process proceeds to step 210.

Step 209 is a step for amplifying the roll component signal v ″ when the steering condition is ON, and then the process proceeds to step 210.

Step 210 uses the following equation 1
This is a step of calculating a control signal V (V ₁ , V ₂ , V ₃ , V ₄ ) for the position of each wheel based on each component signal v, v ′, v ″.

[0044]

[Equation 1] Note that α _f , β _f , γ _f are the proportional constants α _r , β _r , γ _r of the front wheels, and the proportional constants m _f , k _f , m _r , k _r of the rear wheels are the proportional constants β _f , Γ _f , β
Amplification factors for _r and γ _r (however, m _f , k _f , m _r , k _r >
1.0) v ₁ , v ₁ ′, v ₁ ″: sprung vertical speed signal on the front left wheel v ₂ , v ₂ ′, v ₂ ″: sprung vertical speed signal on the right front wheel v ₃ , v ₃ ′, v ₃ ″: sprung vertical speed signal on the left of the rear wheel v ₄ , v ₄ ′, v ₄ ″: sprung vertical speed signal on the right of the rear wheel.

In each equation, the first part bounded by α _f and α _r is the bounce rate, and β _f · m
_The part bounded by _f and β _r · m _f is the pitch rate, and the part bounded by γ _f · k _f and γ _r · k _f is the roll rate. In this way, the bounce rate (spring top / bottom speed), pitch rate, and roll rate are obtained from the signals from the up / down G sensor 1.
The portions of the sensor 1 and the control unit 4 that determine these elements form the sprung vertical velocity detecting means, pitch rate detecting means, and roll rate detecting means.

FIG. 18 shows the operation of the steering condition judging part from step 206 to step 208. As shown in this figure, the steering condition is that the steering angle signal θ and the steering angular velocity ω are , And both are turned on when a predetermined threshold value b is exceeded, and then the steering angle signal θ and
After both the steering angular velocities ω have fallen below the predetermined threshold value b, they are turned off when the control signal V becomes zero.

Next, the operation of the embodiment apparatus will be described with reference to the time chart of FIG.

When the sprung vertical velocity changes as shown by the control signal V in this figure, as shown in the figure, the control signal V
Is a value between the predetermined thresholds δ _T and −δ _C , the shock absorber SA is controlled to the soft region SS.

When the control signal V becomes equal to or higher than the threshold value δ _T , the expansion side hard region HS is controlled to fix the compression side to a low damping coefficient, while the expansion side damping coefficient is made proportional to the control signal V. To change. At this time, the damping coefficient C is C = kV
Control so that.

When the control signal V becomes equal to or lower than the threshold value -δ _{C, the} compression side hard region SH is controlled to fix the extension side to a low damping coefficient, while the compression side damping coefficient is made proportional to the control signal V. To change. Also at this time, the damping coefficient C is C = k
・ V is controlled to be V.

In the first embodiment described above, the effects listed below can be obtained.

Since a sufficient control force can be independently generated not only for bounce but also for roll and pitch, a sufficient damping property for moment of inertia can be obtained without deteriorating the riding comfort for road surface input. As a result, the steering stability can be improved.

In obtaining the bounce rate, pitch rate, and roll rate, different constants α,
Since β and γ are used, each rate can be accurately detected based on the sprung vertical velocity even when the sprung resonance frequency, the pitch resonance frequency, and the roll resonance frequency are different in the vehicle.

(Second Embodiment) In the second embodiment, a part of the control unit 4 is different from that of the first embodiment, that is, in the second embodiment, in obtaining the control signal V, the following mathematical expression is used. The arithmetic expression shown in 2 is used.

[0055]

[Equation 2] In the second embodiment, the part for obtaining the bounce component v is different, and the bounce component v is different from each shock absorber S.
Only the component at position A is input. Therefore, this second
Compared to the first embodiment, the embodiment has a control in which the bounce component of each wheel is emphasized, and has a characteristic in which the vibration damping property with respect to the roll and the pitch is suppressed.

Although the embodiment has been described above, the specific structure is not limited to this embodiment, and the present invention includes a design change and the like within a range not departing from the gist of the invention.

For example, in the embodiment, the pitch rate is obtained by the difference between the front and rear sprung vertical velocities, and the roll rate is obtained by the difference between the left and right sprung vertical velocities. A sensor that detects a change in pitch angle or a sensor that detects a change in roll angle may be used.

[0058]

As described above, in the vehicle suspension system of the present invention, the damping coefficient control section obtains a control signal from the sprung vertical velocity, pitch rate and roll rate, and the shock absorber damping is performed based on this control signal. In addition to controlling the coefficient, the pitch correction unit amplifies the pitch rate when the vehicle is in a sudden acceleration / deceleration state, and the roll correction unit amplifies the roll rate when the vehicle is in a predetermined steering state. Therefore, it is possible to obtain an effect that sufficient damping property against moment of inertia can be obtained and steering stability can be improved without deteriorating the riding comfort for road surface input.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a claim showing a vehicle suspension device of the present invention.

FIG. 2 is a structural explanatory view showing a vehicle suspension device of the first embodiment of the present invention.

FIG. 3 is a system block diagram showing a vehicle suspension system of the first embodiment.

FIG. 4 is a sectional view showing a shock absorber applied to the device of the first embodiment.

FIG. 5 is an enlarged cross-sectional view showing a main part of the shock absorber.

FIG. 6 is a damping force characteristic diagram corresponding to the piston speed of the shock absorber.

FIG. 7 is an attenuation coefficient characteristic diagram corresponding to the step position of the pulse motor of the shock absorber.

FIG. 8 is a K of FIG. 5 showing a main part of the shock absorber.
FIG.

FIG. 9 is an M of FIG. 5 showing a main part of the shock absorber.
FIG.

FIG. 10 is a sectional view taken along line NN of FIG. 5, showing a main part of the shock absorber.

FIG. 11 is a damping force characteristic diagram of the shock absorber when the extension side is hard.

FIG. 12 is a damping force characteristic diagram of the shock absorber in a soft state on the extension side and the compression side.

FIG. 13 is a damping force characteristic diagram of the shock absorber in a compression side hard state.

FIG. 14 is a block diagram showing a main part of a control unit of the first embodiment.

FIG. 15 is a flowchart showing the control operation of the control unit of the first embodiment device.

FIG. 16 is a flowchart showing the operation of a subroutine of the control operations of the control unit of the first embodiment device.

FIG. 17 is a steering condition map of the first embodiment device.

FIG. 18 is a time chart showing the operation of the steering condition determination part of the first embodiment device.

FIG. 19 is a time chart showing the damping coefficient control operation of the device of the first example.

[Explanation of symbols]

 a damping coefficient changing means b shock absorber c sprung vertical speed detecting means d pitch rate detecting means e roll rate detecting means f rapid acceleration / deceleration state detecting means g steering state detecting means h damping coefficient control section j control means k pitch correcting section m Roll correction unit

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

[0044]

[Equation 1] Note that α _f , β _f , γ _f are proportional constants α _r , β _r , γ _r of the front wheels, and proportional constants m _f , k _f , m _r , k _r of the rear wheels are proportional constants β _f , Γ _f , β
Amplification factors of _r and γ _r (however, m _f , k _f , m _r , k _r >
1.0) v ₁ , v ₁ ′, v ₁ ″: sprung vertical speed signal on the right front wheel v ₂ , v ₂ ′, v ₂ ″: sprung vertical speed signal on the left front wheel v ₃ , v ₃ ′, v ₃ ": on the rear wheel right spring vertical velocity signal _{v 4, v 4 ', v} 4": a sprung vertical velocity signal of the rear wheel left. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] May 8, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Next, FIG. 5 is an enlarged sectional view showing a portion of the piston 31. As shown in FIG. 5, the piston 31 is formed with through holes 31a and 31b, and each through hole is formed. An expansion side damping valve 12 and a compression side damping valve 20 that open and close 31a and 31b respectively are provided. A communication hole 39 that communicates the upper chamber A and the lower chamber B is formed at the tip of the piston rod 7 that penetrates the piston 31, and the flow passage cross-sectional area of the communication hole 39 is changed. There is provided an adjuster 40 for this purpose, and an extension side check valve 17 and a pressure side check valve 22 that allow and block the flow of the fluid through the communication hole 39 depending on the direction of flow of the fluid. The adjuster 40 is rotated by the pulse motor 3 (see FIG. 4).
Further, at the tip of the piston rod 7, the first
A port 21, a second port 13, a third port 18, a fourth port 14 and a fifth port 16 are formed. Reference numeral 38 in the drawing denotes a retainer on which the pressure side check valve 22 is seated.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5] ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 15, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0055

[Correction method] Change

[Correction content]

[0055]

[Equation 2] In the second embodiment, the part for obtaining the bounce component v is different, and the bounce component v is different from each shock absorber S.
Only the component at position A is input. Therefore, this second
Compared to the first embodiment, the embodiment has a control in which the bounce component of each wheel is emphasized, and has a characteristic in which the vibration damping property with respect to the roll and the pitch is suppressed.

Front page continuation (72) Inventor Mitsuo Sasaki 1370 Atsugi Unisia, Atsugi City, Kanagawa Prefecture (72) Inventor Satoshi Takahashi 1370 Onsuna City, Atsugi City, Kanagawa Prefecture (72) Inventor Kimura Kimura Makoto Atsugi-shi, Kanagawa 1370 Onna, Atsugi Unisia Co., Ltd.

Claims (5)

[Claims] 1. A shock absorber which is interposed between a vehicle body side and each wheel side and whose damping coefficient can be changed by a damping coefficient changing means, and a sprung vertical velocity in the vicinity of the position where each shock absorber is provided is detected. Sprung vertical velocity detecting means, pitch rate detecting means for detecting the pitch rate of the vehicle body, roll rate detecting means for detecting the roll rate of the vehicle body, and sudden acceleration / deceleration state detecting means for detecting the rapid acceleration / deceleration state of the vehicle. A control means having a steering state detecting means for detecting a steering state of the vehicle, and a damping coefficient control section for controlling the damping coefficient of each shock absorber based on a control signal obtained from a sprung vertical velocity, a pitch rate and a roll rate. And provided in the control means, when the vehicle is in a sudden acceleration / deceleration state,
A vehicle suspension device comprising: a pitch correction unit that amplifies the pitch rate; and a roll correction unit that is provided in the control means and that amplifies the roll rate when the vehicle is in a predetermined steering state. 2. The pitch rate detecting means is means for detecting a pitch rate from a sprung vertical speed difference between front and rear of a vehicle body based on the sprung vertical speed detected by the sprung vertical speed detecting means, and the roll rate detecting means. 2. The vehicle suspension system according to claim 1, wherein said means is means for detecting a roll rate from a sprung vertical speed difference between left and right of the vehicle body based on a sprung vertical speed detected by said sprung vertical speed detecting means. 3. The shock absorber includes an expansion side hard region in which the expansion side is variable and the compression side is fixed at a low damping coefficient, and a compression side hard region is in which the compression side is variable and the expansion side is fixed at a low damping coefficient. The damping coefficient control means controls the shock absorber in the extension side hard area when the control signal is equal to or higher than the positive threshold value, by forming the structure having three areas, that is, the soft area having the low damping coefficient on both the side and the compression side. However, when the control signal is below the negative threshold, the shock absorber is controlled in the pressure side hard area, and when the control signal is between the positive and negative thresholds, the shock absorber is controlled in the soft area. The vehicle suspension system according to claim 1, wherein: 4. In obtaining the control signal, the sprung vertical velocity is a signal passed through a bandpass filter including sprung resonance frequencies of the front and rear wheels,
The vehicle suspension according to claim 1, wherein the pitch rate uses a signal that has passed through a bandpass filter including a pitch resonance frequency, and the roll rate uses a signal that has passed through a bandpass filter that includes a roll resonance frequency. apparatus. 5. In obtaining the control signal, a first proportional constant applied to the sprung vertical velocity, a second proportional constant applied to the pitch rate, and a third proportional constant applied to the roll rate are independently provided. The first proportional constant is a numerical value according to the vertical spring constant, and the second proportional constant is a numerical value according to the pitch rigidity,
The vehicle suspension system according to claim 1, wherein the third proportionality constant is a numerical value according to roll rigidity.