JPH07102766B2 - Vehicle suspension - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to improvements in suspension systems.

(Prior Art) It is widely known that a suspension device is provided between an axle and a vehicle body, and the two are coupled to each other to absorb a shock from a road surface to improve riding comfort. The coil spring and a hydraulic shock absorber that appropriately suppresses the vibration of the coil spring by a damping force that accompanies expansion and contraction of the piston rod.

By the way, in recent suspension systems, anti-dive (prevention of leaning of the vehicle body due to braking), anti-roll (prevention of lateral tilt due to turning), and anti-squat are added to the above-mentioned hydraulic shock absorber as part of improving riding comfort. There is a tendency to have each of the functions (prevention of vehicle body tailing due to acceleration). As a configuration that gives each of the functions, when a driving condition in which one of the nose dive, rolling, and squat phenomena occurs, each hydraulic shock absorber in the suspension system of each wheel (all four wheels) is connected to its piston rod. The damping force at the time of expansion and contraction can be switched so as to be extremely large. With this configuration, in each hydraulic shock absorber, the large damping force acts as a reaction force against each phenomenon of nose dive, rolling, and squat, and attempts to prevent the occurrence of each phenomenon as much as possible.

(Problems to be Solved by the Invention) However, each phenomenon of posture change in both front and rear directions such as nose dive, squat, etc. and posture change in both left and right directions such as rolling occurs in the running state of the vehicle, and However, there is a risk that unexpected situations may occur due to road surface conditions, road conditions, etc., simply increase both the damping force when the piston rod expands and contracts to prevent each phenomenon of nose dive, rolling, and squat. Not only is it impossible to cope with unexpected situations, but once each phenomenon occurs in the vehicle body, the restoration of the vehicle body is hindered. To describe such a concrete example in detail with respect to rolling, in the case of turning right when moving forward, in order to prevent rolling of the vehicle body, in order to prevent rolling of the vehicle body, the damping force when shortening the piston rod of each hydraulic shock absorber on the left side in the forward direction Must be large. However, in the above configuration, even in each hydraulic shock absorber on the right side in the forward direction, the damping force at the time of shortening the piston rod is also large, and it happens that the right wheel in the forward direction has a convex portion on the road surface. When riding on the vehicle, the vehicle body is largely repelled due to the synergistic effect of the centrifugal force that tends to tilt outward.

Also, in each hydraulic shock absorber on the left side in the forward direction, once the piston rod is shortened, the damping force when the piston rod is extended is reduced regardless of the damping force generated when the piston rod is shortened due to a sudden right turn or the like. Since the force is also increased, the piston rod is less likely to extend, and when the degree of turning becomes moderate during turning, the restoration of the leaning of the vehicle body is impeded.

The present invention has been made in view of the above circumstances, and an object thereof is to improve the running performance of a vehicle.

(Means for Solving the Problem) In order to achieve the above object, in the vehicle suspension system of the present invention, the damping force characteristic on the extension side of the hydraulic shock absorber provided on each wheel of the vehicle is set to a predetermined damping force. The damping force characteristic on the high side which generates a damping force larger than the characteristic and the damping force characteristic on the lower side which generates a damping force smaller than the predetermined damping force characteristic are at least two stages, and the damping force characteristic on the shortening side Is at least two stages of a damping force characteristic on the high side that generates a damping force larger than a predetermined damping force and a damping force characteristic on the lower side that generates a damping force smaller than the predetermined damping force characteristic. It is possible to select two levels of high and low damping force characteristics on the shortening side by driving an actuator for damping force adjustment provided in each hydraulic shock absorber, and the running state of the vehicle can change the posture in both front and rear directions (nose dive, squat), Ah Or, when the posture changes in both left and right directions (rolling), the damping force characteristics of the hydraulic shock absorber on the extension side due to the posture change are selected so that the extension side is high and the contraction side is low at the same time. In addition, the configuration is characterized in that the damping force characteristic of the hydraulic shock absorber on the shortening side is selected so that the shortening side is high and the extension side is low at the same time.

(Operation) With the above-described configuration, the hydraulic shock absorber U of the suspension system for each wheel is affected by a phenomenon of posture change in both front and rear directions (nose dive, squat) or a posture change in both left and right directions (rolling). In the meantime, the vehicle body is quickly restored even if each phenomenon occurs once.

(Example) Hereinafter, the Example of this invention is described based on drawing.

1 to 4, reference numeral 1 denotes a cylinder of a hydraulic shock absorber U, in which a free piston 2 is slidably fitted in the cylinder 1, and the inside of the cylinder 1 is formed by a free piston 2 in a gas chamber 3 And the oil chamber 4 are defined. Gas chamber 3
Is filled with high-pressure gas, and the oil chamber 4 is filled with oil liquid.

A piston 5 is slidably fitted in the oil chamber 4, and the oil chamber 4 is defined by the piston 5 into a lower chamber R ₁ and an upper chamber R ₂ . A piston rod 6 is connected to the piston 5, and the piston rod 6 extends to the outside of the cylinder 1 through the upper chamber R ₂ .

The piston 5 is provided with a first communication passage 7 and a second communication passage 8 that communicate the lower chamber R ₁ and the upper chamber R ₂ . When the piston rod 6 is shortened, the lower chamber R ₁
When the pressure rises and the pressure difference between the lower chamber R ₁ and the upper chamber R ₂ reaches a certain value, the normally closed first damping valve 9 that opens the first communication passage 7 is opened.
On the other hand, when the piston rod 6 extends, the pressure in the upper chamber R ₂ increases at the lower part of the piston 5 when the pressure difference between the lower chamber R ₁ and the upper chamber R ₂ reaches a certain value. A normally closed second damping valve 10 for opening the communication passage 8 is installed.

The piston 5 is formed with third and fourth communication passages 11 and 12 which face each other with the axis of the piston rod 6 in between, and the third and fourth communication passages 11 and 12 are respectively formed in the upper chamber R ₂ Communicates with the lower chamber R ₁ . Check valves 13 and 14 are provided in the third and fourth communication passages 11 and 12, respectively.
Allows only the flow of oil liquid from the lower chamber R ₁ to the upper chamber R ₂ , and the check valve 14 allows only the flow of oil liquid from the upper chamber R ₂ to the lower chamber R ₁ . A disk-shaped movable plate 15 is rotatably held inside the piston 5 about the axis of the piston rod 6, and the plate surface of the movable plate 15 traverses the third and fourth communication passages 11 and 12. ing. A plurality of orifices a ₁ , a ₂ , b ₁ , b ₂ , c ₁ , c ₂ are bored in the movable plate 15 in the axial direction thereof, and each orifice a ₁ , a ₂ , b ₁ , b ₂ , c ₁ , c ₂ are the third and fourth communication passages obtained by rotating the movable plate 15 about its axis.
It is possible to face 11,12. Each orifice a ₁ ,
a ₂ , b ₁ , b ₂ , c ₁ , c ₂ have orifices facing each other with the axis of the movable plate 15 in between,
a ₁ and a ₂ , orifices b ₁ and b ₂ , orifices c ₁ and c ₂ are paired, and one orifice is the third communication passage 11
The other orifice, the other orifice is the fourth communication passage 12
Will be faced with. The opening areas of the orifices a ₁ , a ₂ , b ₁ , b ₂ , c ₁ , c ₂ are the same for the orifices a ₁ and c ₂ , the orifices b ₁ and b ₂ , and the orifices c ₁ and a ₂ , respectively. It becomes smaller as it becomes a ₁ , orifice b ₁ , and orifice c ₁ .

An operating rod 16 is connected to the movable plate 15 at its axial center, and the operating rod 16 rotatably penetrates the piston rod 6 in its axial direction. Operating rod
An actuator 17 is connected to the actuator 16. The actuator 17 allows the operation rod 16 to rotate appropriately about its axis.

The hydraulic shock absorber U according to the present invention is used as a part of the suspension device for each wheel, and accordingly, the actuator
17 is used for each hydraulic shock absorber U. Each actuator 17a, 17b, 17c, 17d has a control circuit 18 as shown in FIG.
Are connected to various sensors 19 to 26 and an off switch 27 via the, and a display lamp 28 is also connected to the control circuit 18.

The control circuit 18 actuates each actuator 17a~17d in accordance with the output signals from the various sensors 19 to 26 and OFF switch 27, the orifice a ₁ and a ₂ a pair, b ₁ and b _2, c ₁ and c _It has a function of exposing ₂ to the third and fourth communication passages 11 and 12. The switching selection of each orifice will be described later. Here, the hydraulic shock absorber U, the third is faced the orifice b ₁ in the communication passage 11, when to face the orifice b ₂ to the fourth communication passage 12 is in FIG. 3, B ₁ and B ₂ shows a characteristic curve, and these characteristic curves B ₁ and B ₂ are normal damping force characteristics, that is, a standard damping force characteristic that is equivalent to a damping force characteristic set for a suspension device with a fixed damping force characteristic. It has excellent damping force characteristics. The hydraulic shock absorber U, the third is faced orifice a ₁ in the communication passage 11, when to face the orifice a ₂ to a 4 communicating path 12 is gradual rise than the characteristic curve B ₁ A characteristic curve A ₁ and a characteristic curve A ₂ that rises more rapidly than the characteristic curve B ₂ are shown. The orifice C ₁ faces the third communication passage 11 and the orifice C ₂ faces the fourth communication passage 12. when Mase is a characteristic curve C ₁ rapid rise than the characteristic curve B _1, it will show a gradual rise of the characteristic curve C ₂ than the characteristic curve B _2. Then, when the initial damping force at the initial rise exceeds a predetermined value, the first and second damping valves 9 and 10 are opened, and the hydraulic shock absorber U exhibits the predetermined damping force. The opening times of the first and second damping valves 9 and 10 correspond to the points P ₁ and P _{2 at} which the respective characteristic curves bend.

Various sensors 19 to 26 are a vehicle speed sensor 19 and a brake sensor 2.
0, shift position sensor 21, blinker sensor 22, steering wheel angle sensor 23, accelerator opening sensor 24, longitudinal acceleration sensor 25, lateral acceleration sensor 26, and off switch 27.
Consists of.

As the vehicle speed sensor 19, a sensor used for a normal speedometer, speed control, etc. is used. A brake lamp switch is used as the brake sensor 20. The shift position sensor 21 detects at which stage of the forward, backward and forward positions the shift lever is located. A winker switch is used as the winker sensor 22. As the handle angle sensor 23, a potentiometer that rotates with the handle shaft, an absolute rotary encoder, or an incremental rotary encoder with or without zero position is used. As the accelerator opening sensor 24, a switch whose contacts are closed when the accelerator is opened more than a predetermined amount is used. Front-rear acceleration sensor 25 and left-right acceleration sensor
As 26, the inertia of a weight or the like is used to detect an acceleration of a predetermined amount or more and its direction by a switch contact or a phototransistor. The off switch 27 is provided in the driver's seat,
When the driver wants to drive with the suspension characteristic in normal running, the switch 27 is pressed to fix the normal damping force characteristic (in FIG. 2, the orifices b ₁ and b ₂ are fixed).
Is selected. ) Display lamp 28 is selected for switching suspension characteristics (selection of each orifice a ₁ , a ₂ , b ₁ , b ₂ , c ₁ , c ₂ )
And the occurrence of failures of various sensors 19 to 26 are displayed.

Next, each mode of basic control, priority relationship of input information from various sensors, and basic signal processing will be described.

i) Basic control (a) Anti-dive (prevention of posture change in the forward direction) When the brake pedal is depressed when the vehicle speed is higher than a predetermined speed, the vehicle speed sensor 19 and the brake sensor 20 cause the longitudinal acceleration sensor 25.
Detects the state, and each detection signal is input to the control circuit 18. The control circuit 18 outputs an output signal corresponding to each of the actuators 17a to 17d based on the both detection signals,
The actuators 17a to 17d are operated. That is, in each hydraulic shock absorber U on the front side, the movable plate 1
5, 15 are rotated by the actuators 17a, 17b, the orifice c ₁ faces the third communication passage 11, the orifice c ₂ faces the fourth communication passage 12, and the orifice a ₂ faces the fourth communication passage 12. Face. On the other hand, in each hydraulic shock absorber U on the rear side,
The orifice a ₁ of the movable plates 15 and 15 faces the third communication passage 11,
The orifice a ₂ faces the fourth communication passage 12. Therefore, in each hydraulic shock absorber U on the front side, when the piston rod 6 is shortened, the damping force is in a normal state (orifice).
b _1, the case of selecting the b ₂₎ becomes larger than the damping force is smaller than the normal state at the time of extension of the piston rod 6. Therefore, the shortening movement becomes hard and the extension movement becomes soft. Further, in each hydraulic shock absorber U on the rear side, the damping force becomes larger than the normal state when the piston rod 6 is extended, and becomes smaller than the normal state when the piston rod 6 is shortened. Therefore, the extension movement is hard and the extension movement is soft. As a result, the nose dive can be sufficiently dealt with, while the vehicle body is quickly restored even if the nose dive occurs.

Incidentally, the anti-dive action is reverse to the above when traveling in reverse.

(B) Anti-roll (prevention of posture change in both left and right directions) When the steering wheel is turned to the left or right at a predetermined angle or more at a predetermined vehicle speed or higher, or either of the left and right winkers is turned on, that state is determined by the vehicle speed sensor 19 and the steering wheel angle sensor 23. The horizontal acceleration sensor 26 and the turn signal sensor 22 detect the detected signals, and the respective detection signals are input to the control circuit 18. The control circuit 18 outputs an output signal corresponding to each of the actuators 17a to 17d based on each of the above detection signals to operate each of the actuators 17a to 17d. That is, when the steering wheel is turned to the right or the turn signal indicating the right turn is turned on, left rolling occurs. Therefore, in each hydraulic shock absorber U on the right front rear side in the forward direction, the third communication passage is provided. 11 orifices a ₁ of the movable plate 15, 15 faces the, face orifice a ₂ to a 4 communicating path 12. On the other hand, in each hydraulic shock absorber on the left front rear side facing the forward direction, the movable plate 1
The orifices c _{1 of} 5, 15 face the third communication passage 11, and the orifice c ₂ faces the fourth communication passage 12. Therefore, in each of the front and rear hydraulic shock absorbers U on the right side in the forward direction, the damping force becomes larger than the normal state when the piston rod 6 extends, and the normal damping state when the piston rod 6 shortens. Will be smaller than. Therefore, the extension movement becomes hard and the contraction movement becomes soft. Further, in each of the front and rear hydraulic shock absorbers U on the left side in the forward direction, the damping force becomes larger than the normal state when the piston rod 6 is shortened and becomes smaller than the normal state when the piston rod 6 extends. Also becomes smaller. Therefore, when shortening, it becomes hard, and when it extends, it becomes soft. If you turn the steering wheel to the left or turn on the turn signal of the left turn, it will be in the state of rolling right,
In each hydraulic shock absorber U on the front side on the right side in the forward direction, the predetermined orifices c ₁ and c ₂ face the third and fourth communication passages 11 and 12, and the front on the left side in the forward direction. In each hydraulic shock absorber on the rear side,
Predetermined orifices a ₁ and a ₂ face the third and fourth communication passages 11 and 12, respectively. Therefore, in the former case, shortening becomes hard,
Extension movement becomes soft. In the latter, the shortening motion becomes soft and the extension motion becomes hard. This makes it possible to sufficiently cope with the rolling, but even if the rolling is performed, the restoration is quickly performed. In the case of this anti-roll, the turning direction determination by the steering wheel operation is prioritized over the blinker operation.

(C) Anti-squat (preventing posture change in the rearward direction) When the accelerator pedal is depressed for a predetermined amount or more at a predetermined vehicle speed or less, the state of the accelerator pedal is detected by the vehicle speed sensor 19, the shift position sensor 21, the accelerator opening sensor 24, and the longitudinal acceleration sensor 25. , And each detection signal is input to the control circuit 18. Control circuit 18
Outputs an output signal to each of the actuators 17a to 17d based on each of the detection signals. Accordingly, in each hydraulic shock absorber U on the front side, the orifice a ₁ of the movable plate 15, 15 faces the third communication passage 11, and the orifice a ₂ has the fourth communication passage 12.
To face. On the other hand, in the rear hydraulic shock absorber, the movable plate
The orifices c _{1 of} 15 and 15 face the third communication passage 11, and the orifice c ₂ faces the fourth communication passage 12. Therefore, in each hydraulic shock absorber U on the front side, the damping force becomes larger than the normal state when the piston rod 6 is extended, and becomes smaller than the normal state when the piston rod 6 is shortened. Therefore, the extension movement becomes hard and the contraction movement becomes soft. Further, in each hydraulic shock absorber U on the rear side, the damping force becomes larger than the normal state when the piston rod 6 is shortened, and becomes smaller than the normal state when the piston rod 6 is extended. Therefore, the shortening movement becomes hard and the extension movement becomes soft. As a result, while the squat can be sufficiently dealt with, the vehicle body can be quickly restored even if the squat occurs. The anti-squat action is the reverse of that in the case of reverse travel.

ii) Priority of input information from various sensors When acceleration is detected by acceleration sensors 25 and 26 in anti-nose dive action, anti-roll action, and anti-squat action, the detection signal is a detection signal from another sensor. Takes precedence over. This is an acceleration sensor
It is not possible to detect the acceleration before the pre-occurrence due to 25 and 26, but the acceleration that has already occurred, especially when the car body spins during braking or the rear part of the car body flows during turning and the reverse handle is turned. This is because the direction of acceleration can be detected more accurately than in the case of other indirect means when it is cut.

Nose dive and rolling, or squat and rolling overlap, resulting in orifices a ₁ , a ₂ , b ₁ , b ₂ , c ₁ , c ₂
If the switching selection directions (rotating directions of the movable plate 15) conflict with each other, select either one according to the motion characteristics of the vehicle body for each vehicle type, or refer to that value if the magnitude of acceleration can be detected. Then, the priority may be determined. Of course, in the above case, the normal damping force characteristic may be left as it is.

Further, when the traveling states are opposite to each other, for example, each phenomenon of the nose dive and the squat occurs at the same time by the brake signal and the accelerator opening signal, it is determined by the control circuit 18, and the outputs from the acceleration sensors 25, 26 are controlled by the control circuit 18. If is not entered, the orifice is set according to the predetermined priority relationship.
Selection of a ₁ and a ₂ , b ₁ and b ₂ , c ₁ and c ₂ may be determined, or the normal damping force characteristics may be maintained (selection of orifices b ₁ and b ₂ ).

iii) Basic signal processing The output signals from the various sensors 19 to 26 may cause chattering of the contact points of the sensor, or minute signal fluctuations or noise present in the output signal of the sensor may lead to meaningless minute operation of the actuator 17. The following processing is performed so that it will not occur.

For analog quantitative signals such as vehicle speed and steering wheel angle,
Add hysteresis to the threshold. In addition, a delay time element that works only for the disappearance of the signal is provided so as not to lose the quick response to the signal from the switch contact. Also, this delay time element can be used for a signal that the analog signal exceeds the threshold value instead of the above-mentioned hysteresis, or a signal that appears as a result of signal determination, for example, the result of a vehicle speed signal and a brake signal, Control circuit
It can also be used for the nose dive signal output from 18.

The signal processing of the steering wheel angle sensor 23 in the anti-roll is basically performed as a judgment as to whether the steering wheel is turned or not turned over a predetermined angle, but due to its quick response, the steering wheel rotates at a predetermined rotation speed or more even if it does not reach the predetermined angle. When it starts, the same judgment is made.

When a rotary encoder without zero position output is used as a steering wheel angle sensor, the steering wheel angle position corresponding to straight ahead is determined from the past steering wheel angle position, but the determination is straight forward depending on the vehicle speed and the presence / absence of lateral acceleration. It is also corrected by being confirmed.

Although one embodiment has been described above, the present invention also includes the following aspects.

Orifice switching may be selected in two stages. For example, a normal damping force characteristic (selecting orifices b ₁ and b ₂ ) and a damping force characteristic that is larger than the normal state when the piston rod 6 is shortened and smaller than the normal state when the piston rod 6 is extended (the orifice c ₁ , Select c ₂ ) and the combination. In this case, the normal damping force characteristic shortening side (orifice b ₁ ) has a lower damping force characteristic,
The extension side (orifice b ₂ ) corresponds to the damping force characteristic on the high side.

Orifice switching may be selected in four or more stages.
For example, the normal damping force characteristics are divided into two stages, one with a slightly larger size and the other with a slightly smaller size when the piston rod is extended / shortened. The one selected by the switch.

The normal damping force characteristic may be divided into two stages, one for high speed and the other for low speed, and the orifice for low speed may be switched to the orifice for high speed at a predetermined vehicle speed or higher. In this case, the damping force for the high speed is made slightly larger than that for the low speed when the piston rod 6 is extended.

In the above embodiment, the control of the posture change in both the front and rear directions (nose dive, squat) and the posture change in the left and right directions (rolling) is shown in the case where both the front and rear directions and the left and right directions are controlled. Alternatively, either one of the front and rear directions or the left and right directions may be controlled.

(Effects of the Invention) As described in detail above, in the present invention, the phenomenon of posture change in both front and rear directions (nose dive, squat) or posture change in both left and right directions (rolling) is prevented as much as possible. When restoring the posture of the vehicle body, the damping force on the restoration side of the hydraulic shock absorber is on the low side, so it is quick without hindering the restoration of the vehicle body even if the damping force is not controlled at the timing of restoration. The driving performance can be dramatically improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a hydraulic shock absorber according to the present invention, FIG. 2 is a plan view showing a movable plate, and FIG. 3 is a characteristic diagram showing damping force characteristics of the hydraulic shock absorber according to the present invention. 4 is an electric system diagram according to the present invention. U: Hydraulic shock absorber

Claims (6)

[Claims] 1. A damping force characteristic on the extension side of a hydraulic shock absorber provided on each wheel of a vehicle, and a damping force characteristic on the high side for generating a damping force larger than the prescribed damping force characteristic, and the prescribed damping force characteristic. At least two levels of the damping force characteristic on the lower side that generates a smaller damping force are set, and the damping force characteristic on the shortening side is set to a damping force characteristic on the higher side that generates a damping force larger than a predetermined damping force, and the predetermined damping force characteristic. The damping force characteristic of each of the hydraulic shock absorbers is set to at least two levels, namely, the damping force characteristic of the lower side that generates a smaller damping force than the damping force characteristic of the lower side, and the damping force characteristic of the high side and the low side of the extension side and the shortening side. It can be selected by driving an actuator for driving, and the running state of the vehicle can change the posture in both front and rear directions (nose dive, squat), or
When the posture change (rolling) occurs in both the left and right directions, the damping force characteristics of the hydraulic shock absorber on the extension side due to the posture change are selected so that the extension side is high and the contraction side is low at the same time. A vehicle suspension system characterized in that control is performed to select the damping force characteristics of the hydraulic shock absorber on the side of shortening so that the side of shortening is higher and the side of extension is lower at the same time. 2. The damping force characteristic of the hydraulic shock absorber on the rear side is extended when the running state of the vehicle causes a change in the posture of the nose dive or the squat in both the front and rear directions, and when the nose dive occurs. The side that is high is selected so that the shortening side is also the low side at the same time.Furthermore, the damping force characteristic of the hydraulic shock absorber on the front side is selected so that the shortening side is the high side and the extension side is the low side at the same time. , When the machine is in a state of causing squat, the damping force characteristics of the hydraulic shock absorber on the front side are selected so that the extension side is high and the contraction side is low at the same time. The vehicle suspension system according to claim 1, wherein the control is performed so that the shortening side is higher and the extension side is lower. 3. The damping characteristic of the right hydraulic shock absorber is extended when the running state of the vehicle is a state in which the posture of the left rolling or the right rolling is changed in both the left and right directions, and when the state of causing the left rolling is produced. The side that is high is selected so that the shortening side is also the low side at the same time, and further, the damping force characteristics of the left hydraulic shock absorber are controlled so that the shortening side is the high side and the extension side is the low side at the same time. When right rolling occurs, select the damping force characteristics of the left hydraulic shock absorber so that the extension side is high and the shortening side is low at the same time.In addition, the damping force characteristics of the right hydraulic shock absorber are shortened. The vehicle suspension system according to claim 1, wherein the control is performed so that the higher side is the higher side and the extension side is the lower side at the same time. 4. The damping force characteristic of the hydraulic shock absorber is set to be higher than the standard damping force characteristic on the higher side and lower than the standard damping force characteristic on the lower side. The vehicle suspension device according to any one of items 1 to 3. 5. The damping force characteristic of the hydraulic shock absorber is set higher than the standard damping force characteristic on the high side and is equal to the standard damping force characteristic on the lower side. The vehicle suspension device according to any one of items 1 to 3. 6. The damping force characteristic of the hydraulic shock absorber is made equal to the standard damping force characteristic on the high side, and is made lower than the standard damping force characteristic on the low side. The vehicle suspension device according to any one of items 1 to 3.