JPH03204324A - Vehicle suspension device - Google Patents

Abstract

PURPOSE:To improve stability and controllability by variably controlling damping characteristics of shockabsorbers in such a way that contraction damping characteristics on a turning outer wheel side is high upon turning and extension damping characteristic is low and the reverse characteristics are employed on turning inner wheel side. CONSTITUTION:A control unit 7 receives a signal from a turning time detection means to variably control damping characteristics of shockabsorbers 1, 2, 3, 4 in such a manner that contraction damping characteristics are high in the shockabsorbers 1, 3 or 2, 4 and extension damping characteristics are low on a turning outer wheel side meanwhile the contraction damping characteristics are low in the shockabsorbers 2, 4 or 1, 3 on a turning inner wheel side and the extension damping characteristics are high. Likewise, the damping characteristics of the shockabsorbers 1, 3 and 2, 4 on a front wheel side and a rear wheel side are variably controlled on the basis of signals from a braking time detection means and an acceleration time detection means. In this way, stability and controllability which a driver feels can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a suspension system for a vehicle, and particularly relates to a suspension system for a vehicle, and in particular to one in which the damping characteristics of a shock absorber provided corresponding to each wheel can be changed in two stages, high and low. .

(Prior Art) Generally, a suspension system for a vehicle is equipped with a shock absorber for damping vertical motion of a wheel. This shock absorber has variable damping characteristics, so the damping characteristics can be changed in two stages (high and low).
(Refer to Japanese Utility Model Application Publication No. 55-109008), shock absorbers whose damping characteristics can be changed steplessly, and damping characteristics for the compression operation of the shock absorber (i.e. compression damping characteristics) and damping characteristics for the expansion operation (i.e. extension damping characteristics). ) are different.

Among such shock absorbers with variable damping characteristics, the following control methods are known in particular when equipped with a shock absorber whose damping characteristics can be changed in two stages: high and low. In addition, in any of the following control methods, the damping characteristics of the shock absorber are usually lowered (in other words, softer) in order to improve riding comfort.
It is something to do.

■ In order to suppress rolling when turning, the damping characteristics of the shock absorber are increased (in other words, made harder) when a lateral load is detected, and this also prevents the deterioration of maneuverability due to reaction when rolling is restored. It is kept in a hard state for a certain period of time in order to maintain the hardness (see Japanese Patent Application Laid-open No. 151307/1983).

■ To suppress squat during acceleration, increase the damping characteristics of the shock absorber when acceleration is detected (see USP, No. 4,586,728).

■ To suppress nose dive during deceleration, increase the damping characteristics of the shock absorber when deceleration is detected (see EP, No. 0135902).

(Problem to be Solved by the Invention) Hardly changing the damping characteristics of the shock absorber as in the above control method is difficult to change the posture of the vehicle (rolling, etc.).
This has the effect of slowing down the speed of squats or nose dives, but it cannot completely eliminate the change in vehicle body posture, and the change in vehicle body posture still occurs. The reality is that the conventional methods cannot be said to be sufficiently effective in slowing down the speed of change in vehicle body posture.

In addition, since the hard state is maintained until the changes in the vehicle body posture are restored, during this time unsprung vibrations generated by uneven road surfaces are transmitted to the sprung tops, that is, to the vehicle body side, causing a bumpy feeling and worsening ride comfort. There is a problem.

The present invention has been made in view of these points, and its purpose is to more effectively slow down the speed of change in vehicle body posture during turning, braking, or acceleration;
It is an object of the present invention to provide a suspension device for a vehicle that can improve riding comfort.

(Means for Solving the Problems) In order to achieve the above object, the present invention basically uses a shock absorber whose compression damping characteristics and extension damping characteristics can be changed independently, The shock absorber on the side is configured to have high compression damping characteristics and low extension damping characteristics, while the shock absorber on the side to which the expansion force is mainly applied has low compression damping characteristics and high expansion damping characteristics.

The specific configuration of the present invention has three modes corresponding to turning, braking, and acceleration.

The first aspect is to prevent rolling of the vehicle body when turning, and its specific configuration is as described in claim (1), where shocks are applied to each of the front and rear wheels to damp the vertical movement of the wheels. In a suspension device for a vehicle including an absorber, each of the shock absorbers has compression damping characteristics and expansion damping characteristics that can be changed independently, and a turning detection means for detecting when the vehicle is turning;
In response to the signal from the detection means, when the vehicle turns, the compression damping characteristic of the shock absorber on the outer wheel of the turn is made high and the extension damping characteristic is made low, and the compression damping characteristic of the shock absorber of the inner wheel of the turn is made low and the extension damping characteristic is made low. The damping characteristic variable control means is configured to variably control the damping characteristic of the shock absorber so as to increase the damping characteristic.

The second aspect is to deal with the nose dive of the vehicle body during braking, and its specific configuration is to attenuate the vertical movement of each of the front and rear wheels, as described in claim (2). In a suspension device for a vehicle equipped with a shock absorber, each of the shock absorbers has a compression damping characteristic and an extension damping characteristic that can be changed independently, and a braking detection means for detecting when the vehicle is braking; Upon receiving a signal from the means, when the vehicle is braking, the compression damping characteristics of the shock absorber on the front wheel side are made high and the extension damping characteristics are made low, and the compression damping characteristics of the shock absorber on the rear wheel side are made low and the extension damping characteristics are made high. The damping characteristic variable control means variably controls the damping characteristic of the shock absorber.

The third aspect is to deal with the squat of the vehicle body during acceleration, and the specific structure thereof is, as described in claim (3), a shock that damps the vertical movement of each of the front and rear wheels. A suspension device for a vehicle comprising an absorber, wherein each of the shock absorbers is configured such that compression damping characteristics and expansion damping characteristics can be changed independently, and a braking detecting means detects when the vehicle is accelerating; In response to the signal from the detection means, when the vehicle accelerates, the compression damping characteristics of the shock absorber on the rear wheel side are made high and the extension damping characteristics are made low, and the compression damping characteristics of the shock absorber on the front wheel side are made low and the extension damping characteristics are made high. The damping characteristic variable control means variably controls the damping characteristic of the shock absorber so that the damping characteristic of the shock absorber is controlled.

(Function) With the above configuration, in the present invention, when the vehicle is turning, braking, or accelerating, the detection means (
By controlling the damping characteristic variable control means that receives signals from the turning detection means, braking detection means, or acceleration detection means), the compression force is mainly applied to the side to which compressive force is applied (i.e., the outer wheel side when turning, the front wheel side when braking). The compression damping characteristic of the shock absorber is high and the extension damping characteristic is low. Front wheel side during acceleration)
The shock absorber has low compression damping characteristics and high extension damping characteristics.

As a result, the high damping of the shock absorber slows down the speed of changes in vehicle body posture (i.e., rolling during turning, nose dive during braking, or squat during acceleration), similar to the conventional case where the damping characteristics of the shock absorber are uniformly increased. Effects can be obtained. In addition, during this time, small vibrations of the shock absorber caused by unevenness of the road surface tend to act in the opposite direction to the direction of the change in the vehicle body posture, but the damping characteristics of the shock absorber in that direction are low and the shock absorber does not return to its original position. This makes it possible to further slow down the speed at which the vehicle body posture changes.

Moreover, until the car body is restored, the damping characteristics of the shock absorber are not in a completely hard state, but in a semi-hard, semi-soft state, so the unsprung vibrations generated by uneven road surfaces are transmitted onto the sprung surface, that is, on the car body side. can be suppressed from being transmitted to

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

FIG. 1 shows a component layout of a suspension device according to a first embodiment of the present invention.

In FIG. 1, reference numerals 1 to 4 are four shock absorbers provided corresponding to the left and right front wheels 5L (only the left front wheel is shown) and the rear wheel 6L (only the left front wheel is shown), respectively. It dampens the vertical movement of the wheels (that is, the force acting between the vehicle body (spring) and the axle (unsprung)). Each of the shock absorbers 1 to 4 has a built-in actuator 30 (see Fig. 2) that allows the damping characteristics or damping force to be changed in two levels, high and low, and to adjust the relative displacement between the vehicle body and the axle. It has a built-in vehicle height sensor (not shown) for detection. Reference numeral 7 denotes a control unit that outputs control signals to the actuators in each of the shock absorbers 1 to 4 to variably control the damping characteristics thereof. A detection signal is output from the vehicle speed sensor.

Further, 11 to 14 are four acceleration sensors that detect the acceleration of the vehicle body in the vertical direction (Z direction), 15 is a vehicle speed sensor installed in the meter of the instrument panel that detects the vehicle speed, and 16 is the rotation of the steering shaft. A steering angle sensor 17 detects the steering angle of the front wheels, an accelerator opening sensor 17 detects the accelerator opening, and 18 detects whether the brake is in operation (that is, whether or not it is braking) based on the brake fluid pressure. The brake pressure switch 19 detects the damping characteristics of the shock absorbers 1 to 4 when the driver selects HARD, 5OF.
This is a mode selection switch for switching between T and C0NTR0L modes, and detection signals from these sensors 11 to 17 and switches 18 and 1.9 are all output to the control unit 7.

FIG. 2 shows the structure of the shock absorbers 1 to 4 mentioned above.

However, this diagram omits the vehicle height sensor built into the shock absorber.

In FIG. 2, 21 is a cylinder, and a piston unit 22 formed by integrally molding a piston and a piston rod is slidably inserted into the cylinder 21. The cylinder 21 and piston unit 22 are
They are connected to the axle (unsprung) or the vehicle body (sprung) via separate connection structures.

The piston unit 22 has three orifices 23 to
25 are provided. Orifice 2 of one of them
3 is always open. In addition, the other two orifices 24 consist of a passage that passes from the port 24a, passes through the check valve 26, and exits to the port 24b.
The function of the check valve 26 allows the fluid to move only in this direction. The remaining orifice 25 consists of a passage leading from port 25a through check valve 27 to port 25b, and the check valve 27 allows fluid to move only in this direction. In addition, in the case of the embodiment, the orifice 24
The lower side port 24b and the upper side ports 25a of the orifice 25 are used as one port.

The upper chamber 28 and the lower chamber 29 in the cylinder 21 and the cavities (orifices 23 to 25) in the piston unit 22 communicating with these two chambers 28 and 29 are filled with a fluid having an appropriate viscosity.

This fluid can travel between the upper chamber 28 and the lower chamber 29 through any of the three orifices 23-25.

An actuator 30 is incorporated within the piston unit 22. As shown in FIG. 3, the actuator 30 includes a sleeve 31 and a shaft 32 that are arranged concentrically and relatively rotatably, the center of which is connected to the lower end of the sleeve 31, and a circular hole 33 surrounding the sleeve 31.
a first orifice plate 35 having a circular arc hole 34; a second orifice plate 38 whose center is connected to the lower end of the shaft 32 and which has a circular hole 36 and an arc hole 37 on its periphery; A first motor 39 is connected to rotate the first orifice plate 35 through the sleeve 31, and a first motor 39 is connected to the upper end of the shaft 32 to rotate the second orifice plate 38 through the shaft 32. A second motor 40 is provided. When the first orifice plate 35 is reciprocated within a predetermined angle range by the first motor 39, the circular hole 33 of the first orifice plate 35 is aligned with or removed from the position of the port 24a of the orifice 24. On the path from the port 24a to the check valve 26, in addition to the circular hole 33, there is a circular arc hole 37 of the 24th orifice plate 38. Port 24 is always connected to either part even if it rotates back and forth.
a, and does not affect the passage area of the orifice 24. Therefore, the opening and closing of the orifice 24 is determined only by the relative positional relationship between the first orifice plate 35 and the port 24a, and the opening and closing switching is performed by the first motor 39. Similarly, the opening and closing of the orifice 25 is determined only by the relative positional relationship between the second orifice plate 38 and the port 25b, and the opening and closing switching is performed by the second motor 40.

In the above configuration, the shock absorbers 1 to 4 perform the following operations.

That is, when the circular hole 33 of the first orifice plate 35 is aligned with the port 24a due to the operation of the first motor 39, the piston unit 22 is relatively When the cylinder 21 moves upward and the cylinder 21 moves downward), the fluid passage is through both the 5 orifice 23 and the orifice 24, and the damping characteristics of the shock absorbers 1 to 4 for the extension operation, that is, the extension damping characteristics, are 5OFT. (low attenuation). Conversely, the circular hole 33 of the first orifice plate 35 is
If the fluid is out of position, the fluid will pass through the orifice 23.
Therefore, the expansion damping characteristics of the shock absorbers 1 to 4 are HARD (high damping).

Further, when the circular hole 36 of the second orifice plate 38 is aligned with the port 25b due to the operation of the second motor 40, the shock absorbers 1 to 4 are moved in the compression direction (relatively to the piston unit 22 in the figure). When the cylinder 21 moves downward and the cylinder 21 moves upward), the fluid passes through both the orifice 23 and the orifice 25. low attenuation).

Conversely, when the circular hole 36 of the second orifice plate 38 is removed from the port 25b, the fluid passes only through the orifice 23, and the damping characteristics of the shock absorbers 1 to 4 become HARD (high damping).

Note that the first motor 39 and the second motor 40 (in turn, the first orifice plate 35 and the second orifice plate 3)
8) can operate independently, so the extensional damping characteristics and the compression damping characteristics can be switched and changed independently.

FIG. 4 shows a block configuration of the control section of the suspension device. In FIG. 4, the first vehicle height sensor 41, acceleration sensor 11, and actuator 30a are connected to the front wheel 5L on the left side of the vehicle body.
The second vehicle height sensor 42, acceleration sensor 12 and actuator 30b are mounted on the front wheel on the right side of the vehicle body, and the third vehicle height sensor 43, acceleration sensor 13 and actuator 30 are mounted on the front wheel on the right side of the vehicle body.
c corresponds to the rear wheel 6L on the left side of the vehicle body, and the fourth vehicle height sensor 44, acceleration sensor 14, and actuator 30d correspond to the front wheel on the right side of the vehicle body. Incidentally, the actuators 30a to 30d are the same as the actuator 30 in FIGS. 2 and 3, and the vehicle height sensors 41 to 44 are the same as the actuators 30 in FIGS.
are built into the shock absorbers 17-4.

Furthermore, r1 to r4 are vehicle body inter-axle relative displacement signals output from the first to fourth vehicle height sensors 41 to 44 to the control unit 7, and these signals all take continuous values. This signal is positive when the shock absorbers 1 to 4 extend, and negative when they contract.The relative displacement when the vehicle is stationary is assumed to be zero, and the deviation from this is used to determine the magnitude of the relative displacement. represents.

2G1 to G4 are first acceleration sensors respectively] 1 to 1
This is an absolute vehicle body acceleration signal in the vertical direction (Z direction) that is outputted from 4 to the control unit 7, and all of these signals take continuous values. This signal is positive when the vehicle body receives upward acceleration, and negative when the vehicle body receives downward acceleration.

In addition, the vehicle speed sensor 15 outputs a vehicle speed signal, the steering angle sensor 16 outputs a steering angle signal, and the accelerator opening sensor 17 outputs an accelerator opening signal to the control unit 7. All signals take continuous values. The vehicle speed signal is positive when the vehicle is moving forward, and negative when the vehicle is moving backward. As seen from the driver's side, the steering angle signal is positive when the steering wheel rotates counterclockwise (i.e., when turning left), and negative when it rotates clockwise (i.e., when turning right). .

Further, a brake pressure signal is outputted from the brake pressure switch 18 to the control unit 7, and this signal has two values: ON and OFF. ON means that the brake is being operated, and OFF means that it is not.

VE I to VE 41 VCI to VC4 are actuators 30a to 30a, respectively, from the control unit 7.
These signals are actuator control signals output toward 30d, and these signals take two values of "1" and "0". For example, when the value of VEI is "1", the first
Set the position of the circular hole 33 of the orifice plate 35 to port 2.
The first motor 39 operates in the direction of removing the shock absorber from the shock absorber 4a, and the expansion damping characteristic of the shock absorber (shock absorber 9 incorporating the actuator 30a) 1 becomes HARD. On the contrary, V
When the value of EI is "0", the position of circular hole 33 is set to port 2.
The motor 39 operates in a direction matching 4a, and the expansion damping characteristic of the shock absorber 1 becomes 5OFT. VE2~
The same applies to VE4. For example, when the value of VCI is "1", the second motor 40 operates in a direction to remove the position of the circular hole 36 of the second orifice plate 38 from the port 25b in FIG. 2, and the shock absorber 1 is compressed and damped. The characteristic becomes HARD. Conversely, if the value of VCI is “
0'', the second motor 40 operates in a direction to align the position of the circular hole 36 with the port 25b, and the compression damping characteristic of the shock absorber 1 becomes 5OFT. The same applies to VC2 to VC4.

Furthermore, a mode selection signal is outputted from the mode selection switch 19 toward the control unit 7, and this signal is a plurality of parallel signals, and in the case of this embodiment, 1 HAR
It takes three values: D, 5OFT, and C0NTR0L. HARD
indicates that the driver has selected HARD mode.
FT indicates that 5OFT0 mode is selected, C0NTR0L indicates C0N
This means that TR0L mode is selected. As will be described later, in the case of HARD, both the extensional damping characteristics and compression damping characteristics of all shock absorbers 1 to 4 are H.
It is fixed in the ARD state, and when the shock absorbers 1 to 4 are in the 5OFT state, both the extensional damping characteristics and compression damping characteristics of all the shock absorbers 1 to 4 are fixed in the 5OFT state. Also, C0NTR0L
At this time, the extensional damping characteristics and compression damping characteristics of each of the shock absorbers 1 to 4 are automatically and independently switched to the HARD or 5OFT state depending on the motion state and operation state of the vehicle.

FIG. 5 shows the basic control flow of the control unit 7. This control operation is executed by a control program installed in the control unit 7. This control program is repeatedly activated at a constant cycle (1 to 10 m5) by a separately provided activation program. In addition, [
The normal control flag j is a virtual switch placed in the memory in the control unit 7, and takes a binary value of 1, ON or OFF. The normal control flag is set by a separately provided initialization program when the control unit 7 starts operating.
Initialized to ON. This control operation will be explained below along the flow.

First, in step S1, it is determined whether the normal control flag is ON. When the normal control flag is No, which is set to OFF for some reason, the operation is ended without performing the following control.

If the determination in step Sl is YES, step S2
It is determined whether the mode selection signal is HARD or not.

If this determination is YES (HARD), step S9
Actuator control signal VEI ~ VE41 VC
I to VC4 are all set to 1, and in step S8, the control signals VEI to VE4. Outputs VCI to VC4. As a result, the expansion damping characteristics and the compression damping characteristics of all the shock absorbers 1 to 4 are in the HARD state.

In this case, the operation ends.

If the value of the mode selection signal is not HARD, then in step S3 it is determined whether the value of the mode selection signal is 82 OFT, and if the determination is YES, 5O
At the time of FT, all of the actuator control signals VE l to VE4 and VCI to VC4 are set to O in step SIO, and this control signal VEI is set in step S8.
~VE4, VCI ~VC4 are output.

As a result, the extensional damping characteristics and compression damping characteristics of all the shock absorbers 1 to 4 are both in the 5OFT state. In this case, the operation ends.

Both steps S2 above. Both judgments in S3 were N.

In other words, when the value of the mode selection signal is C0NTR0L, the vertical vehicle body absolute acceleration signals 2c+ to 2c4 are input in step S4, and then this 2c is input in step S5.
, +~2G4 are integrated using a numerical integration method or the like to obtain the vertical vehicle absolute speeds 2c+~2c4. This ZGl~
Since ZG4 is the absolute vehicle body velocity in the vertical direction at the positions of the acceleration sensors 11 to 14, it is converted into the absolute vehicle body velocity in the vertical direction 2s+ to 2s4 at the positions of the shock absorbers 1 to 4 in step S6. Since 2s+ to 2s34 can be obtained if three of Zc+ to Zc and 4 are known, Gl to C3 will be used below, and G4 will be a preliminary value. Here, as shown in FIG. 1, the coordinates of the acceleration sensors 11 to 13 are (XGI, y
G+ ) ~ (XG3° VC3), the coordinates of shock absorbers 1 to 4 are (xs+, ys+) ~ (xs4.
ys4), 'Sl~2S4 is determined by the following formula.

However, the two coefficient matrices and their product are calculated in advance,
It is given as a constant.

Subsequently, in step S7, the actuator control signal VE is
The values of I to ME4 and VCI to VC4 are determined.

The setting of the value of this control signal is based on the absolute velocity of the vehicle body in the vertical direction 3i at the position of each shock absorber 4 bars 1 to 4.
(j = 1. 2. 3. 4) or L that is zero or positive
! si≧0), then vEi =1. Let vci = 0,
Vertical absolute vehicle speed zsi is negative (Zsi<0)
Then, vEi =O, vci =1.

After this setting, actuator control signals VEl to VE41 VC1 to VC4 are output in step S8, and the operation is ended.

According to the basic control described above, when the driver
If L mode is selected, each shock absorber 1
~4 indicates that the extensional damping characteristic is HARD when the absolute velocity of the vehicle body in the vertical direction at that position is positive, that is, the velocity is upward.
state, the compression damping characteristic is in the 5OFT state, and the extensional damping characteristic is in the 5OFT state when the vertical absolute vehicle speed is a negative downward speed.
It becomes OFT state, compression damping characteristic or HARD state. This appropriately suppresses both the phenomenon in which high-frequency vibrations input from the road surface to the unsprung area are transmitted to the unsprung top, and the phenomenon in which low-frequency vibrations input from the road surface to the unsprung area excites resonance on the spring. , it is possible to realize a good ride comfort without any lumpy or squishy feeling.

FIG. 6 shows the auxiliary control flow of the control unit 7. This control operation is executed by a program installed in the control unit 7 together with the basic control program. Like the basic control program, this program is run at a fixed cycle (1 to 10m5) by a separate startup program.
) is activated repeatedly. This control operation will be explained below along the flow.

First, the steering angle signal from the steering angle sensor 16 is input in step SIL, and the vehicle speed signal from the vehicle speed sensor 15 is input in step S12, and the lateral acceleration αy is estimated from both in step S13. After that, in step S14, it is determined whether the absolute value of the lateral acceleration αy is larger than αyo (a positive constant value). Here, since the lateral acceleration αy occurs as the vehicle turns, it is important to determine whether the absolute value of the lateral acceleration αy is greater than a positive constant value αyo when the vehicle is turning. It means that it is determining whether or not it is true. Further, the above-described steps SL1 to S14, the steering angle sensor 16, and the vehicle speed sensor 15 constitute a turning detection means 51 that detects when the vehicle is turning.

Then, when the absolute value of the lateral acceleration αy is smaller than the positive constant value αyo (NO), that is, when the vehicle is not turning, the normal control flag is turned ON in step S20 and the operation is ended. This makes the basic control described above effective. On the other hand, when the absolute value of the lateral acceleration αy is 070 or more, that is, when the vehicle is turning, the normal control flag is turned OFF in step S15. This makes basic control invalid.

Subsequently, in step 81B, it is determined whether the lateral acceleration αy is greater than or equal to zero, that is, whether the turning direction is left or right. When this determination is No, which indicates negative lateral acceleration, that is, when the vehicle is turning rightward in the direction of travel, the shock absorber 1 located on the left side of the vehicle body is moved in step S17.
, 3 to the 5OFT state and the compression damping property to the HARD state, the actuator control signal is set to VE1-Ovc.
l=1. VE 3 =OI VC3-1, and the actuator control signal is set to VE2-1. to set the expansion damping characteristics of the shock absorbers 2 and 4 located on the right side of the vehicle body to the HARD state and the compression damping characteristics to the 5OFT state. VC2
=O, VE4-1. It is set as VC4-0. Further, when the determination is YES, that is, when the vehicle is turning leftward in the direction of travel, the extension damping characteristics of the shock absorbers 1 and 3 located on the left side of the vehicle body are set to the HARD state, and compression damping is performed. In order to set the characteristic to the 5OFT state, the actuator control signal is set to VEI = 1. VCI
=0°v23 =1. Vc 3 is set to 0, and the actuator control signal is set to VE2 =01 VC to set the expansion damping characteristic of the shock absorber 2.4 located on the right side of the vehicle body to the 5OFT state and the compression damping property to the HARD state.
2-1, VE4-0. It is called VC4-1. Above step S17. Actuator control signal V in either S18
After setting E l to VE 41 VCl to VC4, the control signals VEI to VE8 41 VCI to VC4 are output in step S19, and the operation ends.

Through the above steps 16 to S19, upon receiving the signal from the turning detection means 51, when the vehicle turns, the compression damping characteristic of the shock absorber on the outer wheel side of the turn is set to the HARD state, and the extension damping is set to the HARD state when the vehicle turns. a damping characteristic variable control means 52 that controls the actuators of the four shock absorbers 1 to 4 so as to set the characteristic to the 5OFT state, set the compression damping property of the shock absorber on the inner wheel of turning to the 5OFT state, and set the extensional damping property to the HARD state; is configured.

Therefore, according to such auxiliary control, when the vehicle turns, the compression damping characteristics of the shock absorber on the outer wheel side of the turn, which is the side to which compression force is mainly applied, are in the HARD state (
(high damping), the extensional damping characteristic is in the 5OFT state (low damping), and the compression damping property of the shock absorber on the inner wheel side of the turn, which is the side where extensional force is mainly applied, is in the 5OFT state, and the extensional damping property is in the HARD state. Therefore, all shock absorbers 1 to 4 exert a high damping force against the rolling of the vehicle body (lateral tilting toward the outside of the turn) that accompanies turning, and the rolling speed can be effectively reduced. It can be delayed.

In addition, during this time, small vibrations of the shock absorbers 1 to 4 caused by unevenness of the road surface tend to act in the opposite direction to the rolling and tilting direction of the vehicle body, but the damping characteristics of the shock absorbers 1 to 4 in that direction are all 5OFT. Since the shock absorbers 1 to 4 are easily restored and displaced, the rolling speed can be further slowed down. As a result, the stability and maneuverability felt by the driver can be improved.

Moreover, until the car body is restored, the shock absorber 1
The damping characteristic of ~4 is not a full HARD condition, but a half H
Since it is in the ARD half 5 OFT state, it is possible to suppress unsprung vibrations generated by unevenness of the road surface from being transmitted to the sprung portion, that is, to the vehicle body side, and it is possible to improve ride comfort.

7 to 10 show a second embodiment of the invention.

0 FIG. 7 shows a partial end view of shock absorbers 1 to 4 (see FIG. 1), and FIG. 7A shows a partial end view of shock absorbers 1 to 4 (see FIG. 1).
FIG. 7B shows when the damping characteristics of the shock absorbers 1 to 4 are in the 5OFT state. Note that vehicle height sensors built into the shock absorbers 1 to 4 are omitted in this figure.

In FIG. 7, inside the cylinder 61 is a piston unit 62 formed by integrally molding a piston and a piston rod.
The cylinder 61 and the piston unit 62 are each coupled to an axle (unsprung) or a vehicle body (sprung) via separately provided coupling structures.

There are two orifices 63 and 64 in the above piston unit.
is provided. One of the orifices 63 is always open. Further, the other orifice 64 is provided so as to be openable and closable by an actuator 65. The actuator 65 consists of a solenoid 66, a control rod 67, and two springs 68a, 68b. The control rod 673] receives the magnetic force from the solenoid 66 and both springs 6.
The piston unit 62 is moved up and down by the urging force received from the pistons 8a and 68b, and the orifice 64 is opened and closed.

The upper chamber 69 and lower chamber 70 in the cylinder 61 and the cavity in the piston unit 62 communicating with this compartment 69,70 are filled with a fluid of appropriate viscosity. This fluid can move between the upper chamber 69 and the lower chamber 70 through any of the orifices 63,64.

In the above configuration, the shock absorbers 1 to 4 perform the following operations.

That is, when the solenoid 66 is not energized, the force of the spring 68a that biases the control rod 67 downward is set to be stronger than the force of the spring 68b that biases the control rod 67 upward. 67 is pressed downward and closes the orifice 64. Therefore, the only passage for the fluid is the orifice 63, and the damping characteristics of the shock absorbers 1 to 4 are in a HARD (high damping) state.

Further, when the solenoid 66 is energized, the control rod 67 is pulled upward by the magnetic force of the solenoid 66, and the orifice 64 is opened. For this reason, both orifices 63
．． Both 64 serve as fluid passages, and the shock absorber 1
The damping characteristic of ~4 becomes a 5OFT (low damping) state.

As mentioned above, the shock absorbers 1 to 4 are in the HARD state when the solenoid 66 is de-energized.
Even if the control unit 7 should fail, the shock absorbers 1 to 4 can maintain the HARD state and prevent deterioration of steering stability.

FIG. 8 shows a block configuration of the control section of the suspension device. In the case of this second embodiment, the first
The actuator control signal and the function of the mode selection switch are different from those in the embodiment.

That is, the actuator control portions 31-v4 outputted from the control unit 7 to the actuators 65a-65d of the respective shock absorbers 1-4 take two values of "1" and "0".

When “1”, actuator solenoid 66 (seventh
(see figure) is not energized, and the damping characteristics of shock absorbers 1 to 4 are in a HARD state. Further, when the value is "0", the solenoid 66 of the actuator is energized, and the damping characteristics of the shock absorbers 1 to 4 are in the 5OFT state.

Further, the mode selection signal outputted from the mode selection switch 19 to the control unit 7 is a parallel signal of HARD, 5OFT, C0N, as in the first embodiment.
It takes three values of TR0L, but as described later, )(ARD
When , the damping characteristics of all shock absorbers 1 to 4 are HA.
When the RD state is fixed, and the damping characteristics of all shock absorbers 1 to 4 are fixed at the 5OFT state, and the C
When 0NTR0L, the damping characteristics of each of the shock absorbers 1 to 4 are automatically switched to the HARD or 5OFT state depending on the driving and operating conditions of the vehicle.

FIG. 9 shows the basic control of the control unit 7) 4-low. This control operation is carried out by the control unit 7
It is executed by a control program installed in the. This control program is executed by a separately provided startup program.
It is activated repeatedly at a fixed period (1 to 10 m5). still,
The "normal control flag" in the figure is the control unit 7
A virtual switch placed in the internal memory, etc., that can be turned on or off.
Takes two values of F. The normal control flag is initialized to ON by a separately provided initialization program when the control unit 7 starts operating. This control operation will be explained below along the flow.

First, in step S21, it is determined whether the normal control flag is ON. When the normal control flag is No, which is set to OFF for some reason, the operation is ended without performing the following control.

When the determination in step S21 is YES, step S
At step 22, it is determined whether the mode selection signal is HARD. If this determination is YES (HARD), all actuator control signals v1 to v4 are set to 1 in step S32.
is set, and the control signals v1 to V4 are output in step 3315. As a result, the damping characteristics of all the shock absorbers 1 to 4 become in the HARD state. In this case, the operation ends.

When the value of the mode selection signal is not HARD, it is then determined in step S23 whether the value of the mode selection signal is 5OFT, and when the determination is YES (5OFT), the actuator control signals v1 to
All of v4 are set to 0, and the control signals v1 to v4 are output in step S31. As a result, the damping characteristics of all the shock absorbers 1 to 4 are in the 5OFT state.

In this case, the operation ends.

Both steps S22. Both judgments in S23 are NO.
, that is, when the value of the mode selection signal is C0NTR0L, the vehicle body inter-axle relative displacement signal r is determined in step S24.
After inputting 1 to r4, in step S25 these r1 to r
4 is differentiated using a numerical differential method or the like to obtain the relative speeds t1 to t4 between the vehicle body axles. Next, in step 32B, after inputting the vertical vehicle absolute acceleration transformation signals 6 2c+ to 2G4, in step S27, these 2c+ to 2(,4 are integrated by numerical integration method etc. to obtain the vertical vehicle absolute velocity 2G1 to 2G4). Find 2G4.This 2G
1 to 2G4 are the absolute vehicle body speeds in the vertical direction at the acceleration sensor positions, so in step 828 they are converted to the absolute vehicle body speeds in the vertical direction 2 at the positions of each shock absorber 1 to 4.
Convert to s+~2S4. 281~s4 is 2G1~
Since three of 2ca can be calculated if known, 2G1 to 2G3 will be used below, and 2Ga will be a preliminary value. Here, when the origin is appropriately set in the horizontal plane and the xy coordinates are taken (see Fig. 1), the acceleration sensors 11 to
13 coordinates (XGI, yc+) ~ (XG3 ~ ye
3), and the coordinates of shock absorbers 1 to 4 are (xs+
,ys+) ~(XS4~ysa), then 2c
+~2c, 4 is determined by the following formula.

7 However, the two coefficient matrices and their product are calculated in advance,
It is given as a constant.

Subsequently, in step S29, the determination functions h1 to h are determined using the following equations.
Find 4.

hi-i 1-2si (i-1, 2, 3, 4) Then, in step S30, the actuator control signal v1
~Determine the value of v4. The values of the control signals v1 to v4 are set to vl-1 if the judgment function ht for each shock absorber 1 to 4 is zero or positive (hl≧0), and if the judgment function ht is negative (hl <0) then vi
-0.

After this setting, actuator control signals V1 to v4 are output in step S31, and the operation is ended.

According to the basic control as described above, when the driver selects the 008 NTR0L mode, the damping characteristics of each shock absorber 1 to 4 are determined when the determination function hi is positive at that position (that is, when the vehicle body in the vertical direction (When the absolute speed is a positive upward speed and the shock absorber is in an extension state, or when the vertical vehicle absolute speed is a negative downward speed and the shock absorber is in a compression state)
1 (when the ARD state is entered and the judgment function hi is negative (that is, when the absolute vehicle body speed in the vertical direction is a downward speed and the shock absorber is in the extension operation state, or when the absolute vehicle body speed in the vertical direction is an upward speed and the shock absorber is in the extension operation state) Since the 5OFT state is reached (when the compression operation is in progress), similar to the basic control in the first embodiment, there is a phenomenon in which high-frequency vibrations input from the road surface to the unsprung area are transmitted to the springs, and The phenomenon in which low-frequency vibrations input to the springs excite resonance on the springs is also appropriately suppressed, and a good riding comfort without a bumpy or squishy feeling can be achieved.

FIG. 10 shows the flow of the auxiliary control 9 of the control unit 7. This control operation is executed by a program installed in the control unit 7 together with the basic control program. Like the basic control program, this program is run at a fixed cycle (1
~10m5) is activated repeatedly. This control operation will be explained below along the flow.

First, in step S41, the steering angle signal from the steering angle sensor 16 is inputted, and in step S42, the vehicle speed signal from the vehicle speed sensor 15 is inputted, and in step S43, the lateral acceleration αy is estimated from both. After that, in step S44 αy
It is determined whether the absolute value of is larger than αyo (a positive constant value). Here, since the lateral acceleration αy occurs as the vehicle turns, it is important to determine whether the absolute value of the lateral acceleration αy is larger than the positive constant value αyo when the vehicle is turning. It means that it is determining whether or not.

Furthermore, the above steps S41 to S44, the steering angle sensor 16, and the vehicle speed sensor 15 constitute a turning detection means 71 that detects when the vehicle is turning.

0 When the absolute value of the lateral acceleration αy is No, which is smaller than the positive constant value αyo, that is, when the vehicle is not turning, the normal control flag is turned ON in step S52 and the operation is ended. This makes the basic control described above effective. On the other hand, when the absolute value of the lateral acceleration αy is equal to or greater than α10, that is, when the vehicle is turning, the normal control flag is turned OFF in step S45. This makes basic control invalid.

Subsequently, in step 84B, the vehicle body inter-axle relative displacement signal r1
After inputting ~r4, this r1~r4 is input in step S47.
is differentiated using a numerical differential method or the like to obtain the relative speeds 11 to 4 between the vehicle body axles.

Subsequently, in step 84g, it is determined whether the lateral acceleration αy is greater than or equal to zero, that is, whether the turning direction is left or right. When this determination is NO, in the case of negative lateral acceleration, that is, when the vehicle is turning rightward in the direction of travel, in step S49, the shock absorber 1 on the left side of the vehicle body is
．． 3, the relative speed between the vehicle body axles ri (i-1
, 3) is zero or 1 is positive, the damping characteristic (in this case, the extensional damping characteristic) is 5O
Set the actuator control signal to vi = 0 to put it in the FT state.
If the relative speed ri between the vehicle body axles is negative, the actuator control signal is set to vl-1 in order to set the damping characteristic (in this case, the compression damping characteristic) to the HARD state. Regarding the shock absorbers 2 and 4 on the right side of the vehicle, if the relative speed N (i = 2.4) between the vehicle axles is zero or positive, the damping characteristic (
In this case, the actuator control signal is set to vi-1 to set the extension damping characteristic (in this case, the extensional damping characteristic) to the HARD state, and if the relative speed t1 between the vehicle body axles is negative, the damping characteristic (in this case, the compression damping characteristic)
The actuator control signal vi is set to the 5OFT state.
=0.

On the other hand, when the determination in step 848 is YES, that is, when the vehicle is turning leftward in the direction of travel, in step S50, the shock absorber 1.3 on the left side of the vehicle body is If the speed it (t -1,3) is zero or positive, the actuator control signal is set to 2i-1 to set the damping characteristic (extension damping characteristic) to the HARD state, and if the relative speed between the vehicle body axles t1 is negative. The actuator control signal is set to vi-0 in order to bring the damping characteristic (compression damping characteristic) into the 5OFT state. Regarding the shock absorbers 2 and 4 on the right side of the vehicle body, if the relative speed between the vehicle body axles (+ = 2.4) is zero or positive, the actuator control signal is set to Vl to set the damping characteristic (extension damping characteristic) to the 5OFT state. -0, and if the vehicle body inter-axle relative speed i is negative, the actuator control signal is set to vi =1 in order to set the damping characteristic (compression damping characteristic) to the HARD state.

Above step S49. After setting the actuator control signal in any one of S50, the control signals v1 to (4) are output in step S51, and the operation ends.

Through the above steps 848 to S51, upon receiving the signal from the turning detection means 71, the compression damping characteristic of the shock absorber on the outer wheel side of the turning is set to the HARD state, and the expansion damping is set to the HARD state when the vehicle turns, whether turning rightward or turning leftward. The four shock absorbers 1 to 4 are set so that the characteristics are in the 5OFT state, the compression damping characteristics in the shock absorber on the inner wheel side of the turn are in the 5OFT state, and the extension damping characteristics are in the H3 ARD state.
A damping characteristic variable control means 72 is configured to control the operation of the actuators 65a to 65d.

Therefore, in the case of the auxiliary control of the second embodiment, as in the case of the auxiliary control of the first embodiment, when the vehicle turns, the shock absorber on the outer turning wheel side, which is the side to which compression force is mainly applied, The compression damping characteristics are in the HARD state (high damping), the extensional damping characteristics are in the 5OFT state (low damping), and the compression damping characteristics of the shock absorber on the inner wheel side of the turn, which is the side where extensional force is mainly applied, is in the 5OFT state. , the extensional damping characteristic becomes HARD, so the shock absorber 1 due to the delay effect due to high damping and the unevenness of the road surface.
By promoting the return displacement in steps 4 to 4, the rolling speed can be effectively slowed down, and it is also possible to suppress the transmission of unsprung vibrations caused by unevenness of the road surface to the vehicle body.

FIG. 11 shows a modification of the auxiliary control flow of the control unit as a third embodiment of the present invention.

4 This control operation is executed by a program installed in the control unit 7 (see FIGS. 1 and 4) together with the basic control program. Similar to the basic control program, this program is run by a separate startup program.
It is activated repeatedly at a fixed period (1 to 10 m5). This control operation will be explained below along the flow.

First, in step S61, an accelerator opening signal from the accelerator opening sensor 17 is input, and then in step S62, it is determined whether the accelerator opening is larger than a positive constant value aO. This determination regarding the accelerator opening is essentially determining whether or not the vehicle is accelerating, and also the accelerator opening sensor 17 and the step Sol
, S62 constitutes an acceleration detecting means 81 that detects when the vehicle is accelerating.

And, No. where the accelerator opening degree is smaller than a positive constant value α.
At this time, that is, when the vehicle is not accelerating, the normal control flag is turned on in step 36B and the operation is ended.

Turn on the normal control flag 5 As a result, the basic control shown in FIG. 5 becomes effective.

On the other hand, when the accelerator opening is aO or more, that is, when the vehicle is accelerating, the normal control flag is turned OFF in step 863. This makes basic control invalid.

Subsequently, in step S84, the actuator control signal is set to VE to set the expansion damping characteristic of the front wheel side shock absorber 1.2 to the HARD state and the compression damping property to the 5OFT state.
+-1, vct-0, VE2ml, ycza*Q,
Stretch damping characteristics of rear wheel shock absorbers 3 and 4 to 5
In order to set the compression damping characteristic to the HARD state in the OFT state, the actuator control signal is set to VE3 =0. VC3-11VE
4=0, ■c4-1. After that, step S [
Actuator control signal Vε1 to VE41VC1 at i5
~ Outputs VC4 and ends the operation. Step 6 above
3 to S65, the shock absorber 3 on the rear wheel side receives the signal from the acceleration detecting means 81 when the vehicle accelerates.
, 4 to set the compression damping characteristics to the HARD state and the extensional damping characteristics to the 5OFT state, and 6 set the four shock absorbers so that the compression damping characteristics of the front wheel side shock absorbers 1 and 2 are set to the 5OFT state and the extensional damping characteristics to the HARD state. A damping characteristic variable control means 82 is configured to control the operation of actuators 1 to 4.

Therefore, according to such auxiliary control, when the vehicle accelerates, the compression damping characteristic of the shock absorber 3.4 on the rear wheel side, which is the side to which compression force is mainly applied, changes to the HARD state (high damping), and the expansion damping characteristic changes to the HARD state (high damping). is in 5OFT state (low attenuation)
In addition, the compression damping characteristics of the shock absorbers 1 and 2 on the front wheel side, which is the side where the extension force is mainly applied, are 5O.
In the FT state, the extensional damping characteristics become HARD-like, so
When the vehicle body squats (rearward downward vertical inclination), all the shock absorbers 1 to 4 exert a high damping force and can effectively slow down the squat speed.

Additionally, small vibrations of the shock absorbers 1 to 4 caused by unevenness of the road surface tend to act in the opposite direction to the inclination direction of the squat of the vehicle body. are all in the 5OFT state and shock absorbers 1 to 4
Since it is easier to restore and displace, the squat speed can be further slowed down, and stability and maneuverability can be improved. Moreover, until the car body is restored, the damping characteristics of shock absorbers 1 to 4 are not in a completely HARD state, but in a half-HARD, half-OFT state, so that unsprung vibrations caused by uneven road surfaces are transmitted to the car body. It is possible to suppress the transmission of the noise to the vehicle, and it is also possible to improve riding comfort.

FIG. 12 shows a modification of the auxiliary control flow of the control unit as a fourth embodiment of the present invention.

This control operation is executed by a program installed in the control unit 7 (see FIGS. 1 and 4) together with the basic control program. Similar to the basic control program, this program is run by a separate startup program.
It is activated repeatedly at a fixed period (1 to 10 m5). This control operation will be explained below along the flow.

8. First, in step S71, it is determined whether the brake signal from the brake pressure switch 18 is ON. This determination essentially determines whether the vehicle is braking or decelerating, and the brake pressure switch 18 and step S71 detect the braking time of the vehicle. A detection means 91 is configured.

When the brake signal is OFF (No), that is, when the vehicle is not braking, the normal control flag is turned ON in step S75 and the operation is ended.

By turning on the normal control flag, the basic control shown in FIG. 5 becomes effective. On the other hand, the brake signal is ON
At the time of ES, that is, when braking the vehicle, step S72
to turn off the normal control flag. This makes basic control invalid.

Subsequently, in step 873, the actuator control signal is set to VEI to change the expansion damping characteristic of the front wheel side shock absorber 12 to the 5OFT state and the compression damping characteristic to the HARD state.
~0. V (1 to 1. Set vEx = OVC2 = 1, and set the actuator control signal to VF to set the extension damping characteristics of the four shock absorbers 3 and 4 on the rear wheel side to the HARD state and the compression damping characteristics to the 5OFT state.
6-1. VC3~0. VF4 = L v (a-0. Then, in step S74, the actuator control signals VEI~VE4.VC1~VC4 are output, and the operation ends. Through the above steps 572~S74, the braking detection means 91 When braking the vehicle, the compression damping characteristics of the shock absorbers 1 and 2 on the front wheels are set to the HARD state, the extension damping characteristics are set to the 5OFT state, and the compression damping characteristics of the shock absorbers 3.4 on the rear wheels are set to the 5OFT state. A damping characteristic variable control means 92 is configured to control the actuators of the four shock absorbers 1 to 4 so that the extension damping characteristics are in the HARD state in the 5OFT state.

Therefore, according to such auxiliary control, when braking the vehicle, the compression damping characteristics of the shock absorbers 1 and 2 on the front wheels, which are the sides to which compression force is mainly applied, are in the HARD state (high damping), and the extension damping characteristics are in the HARD state (high damping). 5OFT state (low attenuation)
, and the shock absorber 3 on the rear wheel side, which is the side where the extension force is applied, is mainly 0.
．． 4, the compression damping characteristic becomes the 5OFT state and the extensional damping property becomes the HARD state, so the nose dive of the car body (
With respect to the front downward vertical inclination), all the shock absorbers 1 to 4 exert a high damping force, and the nose dive speed can be effectively slowed down.

Furthermore, in the direction in which small vibrations of shock absorbers 1 to 4 act due to unevenness of the road surface (in the direction opposite to the inclination direction of the nose dive), the damping characteristics of shock absorbers 1 to 4 are all in the 5OFT state. Since the shock absorbers 1 to 4 are easily restored and displaced, the nose dive speed can be more effectively delayed, and stability and maneuverability can be improved. Moreover, the damping characteristics of the shock absorbers 1 to 4 in the half-HARD and half-5OFT states can suppress unsprung vibrations generated by uneven road surfaces from being transmitted to the vehicle body, thereby improving riding comfort. can.

Figures 13 to 15 show the fifth embodiment 1 of the present invention. shows.

FIG. 13 shows a component layout of the suspension device, and FIG. 14 shows a block configuration of a control section of the suspension device. This embodiment differs from the first embodiment in that it includes a longitudinal acceleration sensor 101 that detects acceleration of the vehicle body in the longitudinal direction (X direction). The longitudinal acceleration sensor 101 outputs a longitudinal acceleration signal to the control unit 7. This signal takes a continuous value, and is positive when the vehicle body receives acceleration in the forward direction, and negative when the vehicle body receives acceleration in the backward direction. Note that the other configurations are the same as in the first embodiment, so the same members are given the same reference numerals and their explanations will be omitted.

FIG. 15 shows the auxiliary control flow of the control unit 7. This control operation is executed by a program installed in the control unit 7 together with the basic control program. Like the basic control program, this program is run at a fixed cycle (1 to 10 m) by a separate startup program.
5) is activated repeatedly. This control operation will be explained below along the flow.

First, after inputting the longitudinal acceleration signal αX from the longitudinal acceleration sensor 101 in step S81, it is determined in step S82 whether the absolute value of this acceleration αX is larger than a positive constant value αxo. If this determination is NO, the normal control flag is turned on in step 888, and the operation ends. By turning on the normal control flag, the basic control shown in FIG. 5 becomes effective.

On the other hand, when the determination in step S82 is YES, the normal control flag is turned OFF in step S83. This makes basic control invalid. Next, step S
At 84, it is determined whether the acceleration αX is zero or positive. This determination essentially determines whether the acceleration state of the vehicle is when the vehicle is accelerating or when the vehicle is braking. Further, the longitudinal acceleration sensor 101 and step 5lit-884 constitute acceleration/braking detecting means 102 that detects when the vehicle is accelerating and braking.

3 When the determination in step S84 is YES,
That is, when the vehicle accelerates, in step S85, the extension damping characteristic of the front wheel side shock absorber 1.2 is changed to HA.
In the RD state, set the actuator control signal to VEI -11VC+ -01V to set the compression damping characteristic to the 5OFT state.
F6-1. VC2-0, and the actuator control signal is set to YES -01VC3-11VF4-0. to set the extension damping characteristic of the shock absorber 3.4 on the rear wheel side to the 5OFT state and the compression damping property to the HARD state. VC4-
Set to 1.

On the other hand, when the determination in step S84 is No, that is, when the vehicle is braking, an actuator control signal is sent in step SOB to set the extension damping characteristic of the front wheel shock absorber 1.2 to the 5OFT state and the compression damping property to the HARD state. VEI-0, VCI=1. VF6 =01 VC
2-1, and the actuator control signal is set to V E 3-1 to set the extension damping characteristic of the rear wheel side shock absorber 3.4 to the HARD state and the compression damping property to the 5OFT state.
r V C3-4 0, VE4 =1. Set VC4=0.

Then, step S85. 88B, actuator control signals VEI to VE41VC1 to V
After setting C4, step S87 lever control signal VE
I ~ VE 4 , outputs VC1'+VC4,
Finish the operation. Through the above steps 885 to S87, the signal from the braking detecting means 91 is received, and the compression damping characteristic of the shock absorber on the front wheel side or the rear wheel side, on which compression force mainly acts, is determined by H when the vehicle is braking or accelerating.
The four shock absorbers are set to the ARD state, the extensional damping characteristic to the 5OFT state, the compression damping property of the shock absorber on the rear wheel side or the front wheel side where extensional force mainly acts to the 5OFT state, and the extensional damping property to the HARD state. A damping characteristic variable control means 103 is configured to control the operation of the first to fourth actuators 30a to 30d.

Therefore, according to such auxiliary control, when braking the vehicle, the compression damping characteristic of the shock absorber 1.2 on the front wheel side, which is the side to which compression force is mainly applied, is in the HARD state (high damping), and the expansion damping is in the HARD state (high damping). Characteristic is 5
The compression damping characteristic of the shock absorber 3.4 on the rear wheel side, which is the side where the extension force is mainly applied, is in the OFT state (low damping), and the extension damping property is in the HARD state.
Therefore, all the shock absorbers 1 to 4 exert a high damping force when the vehicle body nose dives, and the nose dive speed can be effectively slowed down.

Furthermore, when the vehicle is accelerating, the compression damping characteristics of the shock absorbers 3 and 4 on the rear wheel side, which are the sides to which compression force is mainly applied, are in the HARD state, and the extension damping characteristics are in the 5OFT state. The compression damping characteristics of the shock absorbers 1 and 2 on the front wheel side, which is the side that applies, are in the 5OFT state, and the extension damping characteristics are in the HARD state, so all shock absorbers 1
~ 4 will exert a high damping force and can effectively slow down the squat speed.

It should be noted that the present invention is not limited to the first to fifth embodiments described above, but includes various other modifications. For example, in the first embodiment, the control unit 7 calculates the lateral acceleration of the vehicle body based on the steering angle signal from the steering angle sensor 16 and the vehicle speed signal from the vehicle speed sensor 15. Of course, the lateral acceleration may be directly detected using the .

(Effects of the Invention) As described above, according to the invention described in claim (1), in addition to the effect of slowing down the rolling speed of the vehicle body due to the high damping of the shock absorber during cornering, the As a result, when the shock absorber undergoes small vibrations, the shock absorber is likely to be displaced back, so that the rolling speed of the vehicle body can be more effectively slowed down, and the stability and maneuverability felt by the driver can be improved.

Moreover, the damping characteristics of the shock absorber until the car body returns to its original state are semi-hard and semi-soft, making it possible to suppress unsprung vibrations generated by uneven road surfaces from being transmitted to the car body. It is possible to improve the riding comfort.

Further, according to the invention described in claim (2), the sheath dive speed of the vehicle body during braking can be more effectively delayed as in the case of the invention described in claim (1), thereby improving stability and maneuverability. In addition, it is possible to suppress transmission of unsprung vibrations to the vehicle body during braking, thereby improving ride comfort.

Furthermore, according to the invention set forth in claim (3), the squat speed of the vehicle body during acceleration can be more effectively delayed as in the case of the invention set forth in claim (1), thereby improving stability and maneuverability. In addition to being able to improve
It is possible to suppress the transmission of unsprung vibrations to the vehicle body during acceleration, thereby improving riding comfort.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and are shown in FIGS. 1 to 6.
The figures show the first embodiment; FIG. 1 is a perspective view showing the layout of the parts of the suspension device; FIG. 2 is a vertical 8-side view showing a part of the shock absorber; FIG. 4 is a block configuration diagram of a control section of the suspension device, FIG. 5 is a flowchart of basic control, and FIG. 6 is a flowchart of auxiliary control. 7 to 10 show the second embodiment, FIG. 7 is a diagram equivalent to FIG. 2, FIG. 8 is a diagram equivalent to FIG. 4, FIG. 9 is a diagram equivalent to FIG. 5,
FIG. 10 is a diagram corresponding to FIG. 6. Figures 11 and 12
The figures are views corresponding to FIG. 6 showing the third and fourth embodiments, respectively. 13 to 15 show the fifth embodiment,
13 is a diagram equivalent to FIG. 1, FIG. 14 is a diagram equivalent to FIG. 4, and FIG. 15 is a diagram equivalent to FIG. 6. 1 to 4... Shock absorber 5L... Front wheel 6L... Rear wheel 7... Control unit 51.71... Turning detection means 81... Acceleration detection means 91... Braking detection Means 102...Acceleration/braking detection means 9 52, 72, 82. 92. 103... Attenuation characteristic variable control means 0 -189 ゐUnexamined Japanese Patent Publication No. 3 204324 (18) Fig. 8

Claims (3)

[Claims] (1) A suspension system for a vehicle that is equipped with shock absorbers that correspond to each of the front and rear wheels and damp the vertical motion thereof, and the compression damping characteristics and expansion damping characteristics of each of the above-mentioned shock absorbers can be changed independently. is provided with a turning detection means for detecting when the vehicle is turning, and receives a signal from the detection means to increase compression damping characteristics and lower extension damping characteristics in a shock absorber on the outer wheel side of turning when the vehicle turns. A suspension device for a vehicle, comprising: damping characteristic variable control means for variably controlling the damping characteristic of the shock absorber so that the compression damping characteristic of the shock absorber on the inner wheel side of the turning is low and the extension damping characteristic is high. (2) A suspension device for a vehicle that is equipped with shock absorbers that correspond to each of the front and rear wheels and damp the vertical motion thereof, and the compression damping characteristics and expansion damping characteristics of each of the above-mentioned shock absorbers can be changed independently. and a braking detecting means for detecting when the vehicle is braking, and receiving a signal from the detecting means to increase the compression damping characteristic and lower the extensional damping characteristic of the shock absorber on the front wheel side when the vehicle is braking. 1. A suspension device for a vehicle, comprising: damping characteristic variable control means for variably controlling the damping characteristic of the shock absorber so that the compression damping characteristic of the shock absorber on the rear wheel side is low and the extension damping characteristic is high. (3) A suspension system for a vehicle that is equipped with shock absorbers that damp the vertical motion of each of the front and rear wheels, wherein the compression damping characteristics and expansion damping characteristics of each of the above-mentioned shock absorbers can be changed independently. is provided with an acceleration detecting means for detecting when the vehicle is accelerating; and receiving a signal from the detecting means, the compression damping characteristic of the shock absorber on the rear wheel side is set high and the extension damping characteristic is set low when the vehicle accelerates. A suspension device for a vehicle, comprising: damping characteristic variable control means for variably controlling the damping characteristic of the shock absorber so that the compression damping characteristic of the shock absorber on the front wheel side is low and the extension damping characteristic is high.