JPH0573603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a suspension system for a vehicle, and more particularly to an improvement in a suspension system that reduces roll generated in a vehicle body during turning.

[Technical background of the invention and its problems]

Conventionally, as shown in Japanese Unexamined Patent Publication No. 125913/1983, a fluid spring chamber is provided in each of the left and right suspension units, and communication between the left and right fluid spring chambers is provided.
A communication control means for controlling the cut-off is provided, and the communication control means is set to the cut-off state according to the lateral acceleration acting on the vehicle body during turning or the steering condition, and a set amount of fluid is supplied to the fluid spring chamber on the contraction side with respect to the roll direction of the vehicle body. Suspension devices are known that are configured to supply fluid and to discharge a set amount of fluid from a fluid spring chamber on the extension side. In this type of suspension device, when transitioning from cornering to straight-ahead driving, the communication control means is controlled to be in a communicating state in order to return the left and right fluid spring chambers, which had maintained a differential pressure, to the state before the control. However, for example, if the steering wheel is suddenly turned back while driving at high speed in an attempt to avoid an obstacle on the road surface, the vehicle body attempts to return from its roll state to a neutral state, while the communication control means enters the communication state and the vehicle body Since the roll rigidity of the vehicle is reduced, the vehicle body passes through its neutral state and rolls to the opposite side, resulting in a so-called rolling motion of the vehicle body.

Therefore, as shown in Japanese Patent Application Laid-Open No. 61-125913, the steering wheel is steered toward its neutral position at a steering speed higher than the set value, and then the steering angle returns to the set neutral range within the set time. There is a known suspension device that is configured to reduce the rollover of the vehicle body by determining that the rollback of the vehicle body will occur when the roll control is reached, and executing roll control in the opposite direction to the roll control that has been executed. ing.

However, since the steering angle is used as a condition for the yaw control, if for some reason the phase of the part that detects the steering angle deviates from the actual absolute steering angle, the above yaw control This results in the problem of not being able to sufficiently reduce the rolling motion of the vehicle body.

[Purpose of the invention]

The present invention was devised to solve the above-mentioned problems, and an object of the present invention is to provide a suspension device for a vehicle that can effectively reduce body rollback without using any absolute steering angle for control.

[Structure of the invention]

The present invention provides left and right suspension units that respectively support a left wheel and a right wheel and each have a fluid spring chamber, and a fluid supply unit that supplies fluid to each of the fluid spring chambers through a supply valve for the left wheel and a right wheel, respectively. a fluid discharge device that discharges fluid from each of the fluid spring chambers through left wheel and right wheel discharge valves, respectively;
A communication control means for controlling communication and cutoff between the fluid spring chambers of the left and right suspension units, a vehicle speed sensor for detecting vehicle speed, a steering sensor for detecting steering speed, and detecting lateral acceleration acting on the vehicle body. and an acceleration sensor for causing a roll to occur in the vehicle body based on the outputs of these sensors, and when it is determined that a roll occurs in the vehicle body, the communication control means shuts off the left and right fluid spring chambers, and the supply of the suspension unit on the contraction side with respect to the roll direction. A suspension comprising a valve and a control device that outputs a first control signal that causes the exhaust valve of the extension side suspension unit to perform air supply and exhaust control that opens the exhaust valve for a first set time, the control device comprising: After outputting the first control signal, the steering sensor detects that the steering is on the return side and the steering speed is equal to or higher than the first set steering speed, and the acceleration sensor indicates that the lateral acceleration is on the return side and the lateral acceleration is on the return side. When it is detected that the lateral acceleration is equal to or higher than the set lateral acceleration of No. 1, the communication means performs supply in the opposite direction to the roll control executed based on the first control signal while keeping the left and right fluid spring chambers cut off. outputting a third control signal that causes the exhaust control to be executed for a second set time, and further when detecting that the lateral acceleration is less than the second set lateral acceleration after the third set time has elapsed; The suspension device for a vehicle is characterized in that the communication control means outputs a fourth control signal that causes the left and right air spring chambers to communicate with each other.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, FS1 is a suspension unit on the left front wheel side, FS2 is a suspension unit on the right front wheel side, RS1 is a suspension unit on the left rear wheel side, and RS2 is a suspension unit on the right rear wheel side. Each of these suspension units FS1, FS2, RS1, and RS2 has a similar structure to each other, so the suspension units FS1, FS2, RS1, and RS2 have the same structure. The system unit will be explained using the symbol S.

The suspension unit S is equipped with a shock absorber 1. This shock absorber 1
The piston rod 2 includes a cylinder attached to the wheel side, and a piston rod 2 having a piston slidably fitted in the cylinder and having an upper end supported on the vehicle body side. In addition, the suspension unit S is located at the top of this shock absorber 1.
An air spring chamber 3 having a vehicle height adjustment function is provided coaxially with the piston rod 2. This air spring chamber 3 is partially formed by a bellows 4, and by supplying and discharging air to and from this air spring chamber 3 through a passage 2a provided in the piston rod 2, the vehicle height can be raised or lowered. can do.

A control rod 5 is disposed within the piston rod 2 and is provided with a valve 5a at its lower end for adjusting the damping force. Same control rod 5
is rotated by an actuator 6 attached to the upper end of the piston rod 2 to drive the valve 5a.

The compressor 11 compresses the atmospheric air taken in from the air cleaner 12 and supplies it to the high pressure reserve tank 15a via the dryer 13 and check valve 14.
to be sent to. That is, since the compressor 11 compresses the atmospheric air taken in from the air cleaner 12 and supplies it to the dryer 13, compressed air dried by silica gel or the like in the dryer 13 is stored in the high-pressure reserve tank 15a. The compressor 16 has its suction port connected to the low pressure reserve tank 15b and its discharge port connected to the high pressure reserve tank 1.
5a, respectively. Reference numeral 18 denotes a pressure switch that is turned on when the pressure in the low pressure reserve tank 15a exceeds a first set value (for example, atmospheric pressure). The compressor 16 is driven by a compressor relay 17 which is turned on by a signal from a control unit 36, which will be described later, when an on signal from the pressure switch 18 is output. As a result, the pressure within the low pressure reserve tank 15b is always maintained below the first set value.

Air is supplied from this high-pressure reserve tank 15a to each suspension unit S as shown by solid arrows in FIG. That is, the compressed air in the high pressure reserve tank 15a is supplied to the air supply flow rate control valve 19 and the front air supply solenoid valve 2.
0, the suspension unit FS1 via the check valve 21, the front left solenoid valve 22, and the front right solenoid valve 23.
Sent to FS2. Similarly, the compressed air in the high pressure reserve tank 15a is supplied to the air supply flow rate control valve 19, the rear air supply solenoid valve 24, the check valve 25, the rear solenoid valve 26,
It is sent to the suspension units RS1 and RS2 via the rear right solenoid valve 27. The air supply flow rate control valve 19 described above has two positions: a first position (ON state) where the compressed air supplied to each suspension unit S passes through the small diameter passage L, and a second position (OFF state) where the compressed air passes through the large diameter passage. ) can be taken.

On the other hand, exhaust from each suspension unit S is performed as shown by the broken line arrows in FIG. In other words, the compressed air in the suspension units FS1 and FS2 is fed into the low pressure reserve tank 15b via the solenoid valves 22, 23 and the exhaust direction switching valve 28, which is a three-way valve; 23, the exhaust direction switching valve 28, the check valve 29, the dryer 13, the exhaust solenoid valve 31, and the air cleaner 12. Similarly, the compressed air in the suspension units RS1 and RS2 is supplied into the low pressure reserve tank 15b via the solenoid valves 26 and 27 and the exhaust direction switching valve 32, and in other cases, the compressed air is
7. Exhaust direction switching valve 32, check valve 3
3, dryer 13, exhaust solenoid valve 31,
It may be discharged to the atmosphere via the check valve 46 and air cleaner 12. Note that between the check valves 29, 33 and the dryer 13,
A passage L is provided that has a smaller diameter than the passage that directly communicates the exhaust direction switching valves 28, 32 and the low pressure reserve tank 15b.

Note that the solenoid valves 19, 22,
23, 26, 27, 28 and 32, as shown in Fig. 2 A and B, when ON (energized state) the air flows as indicated by arrow A, and when OFF (non-energized state) the air flows as indicated by arrow B. Each allows air circulation. In addition, the air supply solenoid valves 20, 24 and the exhaust solenoid valve 31 are turned ON as shown in FIG. 3A and B.
When it is energized (energized state), air circulation is allowed as shown by arrow C, and when it is OFF (de-energized state), air circulation is prohibited.

34F is a front vehicle height sensor installed between the lower arm 35 of the front right suspension of the vehicle and the vehicle body to detect the front vehicle height, and 34R is a sensor between the lateral rod 37 of the rear left suspension of the vehicle and the vehicle body. This is a rear vehicle height sensor installed to detect the rear vehicle height. Both vehicle height sensors 34F and 34R
The signals detected respectively in the control unit 3
6. In addition, control unit 3
Although not shown, the reference numeral 6 includes a microcomputer, necessary memory and timer, an output circuit for driving each valve, an input circuit for reading each switch, and a sensor.

38 is a vehicle height sensor built into the speedometer, which supplies a detected vehicle speed signal to the control unit 36. 39 is an acceleration sensor that detects lateral acceleration acting on the vehicle body. The acceleration sensor 36 can be of various known types, but in this embodiment, a differential transformer type acceleration sensor that can detect the value of the acting damping force in an analog manner is used. An acceleration signal is supplied to the control unit 36. A brake switch 30 is a brake operation detection sensor that detects the depression state of a brake pedal (not shown), and is turned on when the brake pedal is depressed.

40 is the rotation speed of the steering wheel 41;
In other words, the steering angular velocity and the steering wheel 4
This is a steering sensor that can detect the direction of rotation of the vehicle. Although various types of steering sensor 40 can be adopted, the steering sensor 40 adopted in this embodiment
will be explained according to FIG. A rotary plate 40b that is linked to the steering wheel 41 and has slits 40a formed at predetermined intervals along the circumferential direction.
and two sets of photo interrupters 40c and 40d arranged to sandwich the rotary plate 40b,
When the rotating plate 40b rotates, the photo interrupter 4
The slit 40a passes through the photo interrupters 40c and 40d, and the photo interrupters 40c and 40d output ON and OFF signals. The control unit 36 then controls the photo interrupter 4.
By detecting the output signals of 0c and 40d,
As shown in FIG. 5, the rotational speed of the rotating plate, that is, the steering speed, is determined by measuring the time t1 from when the photo interrupter 40c or 40d turns from ON to OFF, or the time t2 from when it turns ON to the next time. I can do it. Further, as shown in FIG. 5, the control unit 36 determines the direction of rotation of the rotating plate by checking which of the photo interrupters 40c and 40d is turned on first after both photo interrupters 40c and 40d are in the OFF state. In other words, the direction of rotation of the steering wheel can be determined.

42 is an accelerator opening sensor that detects the depression angle of an accelerator pedal of the engine (not shown). Signals detected by these sensors 30, 40 and 42 are supplied to a control unit 36.
43 is a compressor relay for driving the compressor 11, and this compressor relay 4
3 is controlled by a control signal from a control unit 36. 44 is high pressure reserve tank 1
The pressure inside 5a is the second set value (e.g. 7Kg/cm ² )
This is a pressure switch that is turned ON when the pressure is below 0.05, and the signal from this pressure switch 44 is supplied to the control unit 36. The control unit 36 then outputs a signal to the compressor relay 41 to drive the compressor 11 when the pressure in the high pressure reserve tank 15a becomes below the set value and the pressure switch 44 is turned on. As a result, the pressure within the high-pressure reserve tank 15a is always maintained at or above the second set value. However, even if the pressure switch 44 is ON, the control unit 36 indicates that the pressure switch 18 is ON, that is, the compressor 1
The compressor 11 is configured to be prohibited from being driven when the compressor 6 is being driven. A pressure sensor 45 is provided in a passage that communicates the solenoid valves 26 and 27 with each other, and detects the internal pressure of the rear suspension units RS1 and RS2.

In addition, each of the above-mentioned solenoid valves 19, 20,
22, 23, 24, 26, 27, 28, 31 and 32 are controlled by control signals from a control unit 36.

Next, the operation of the apparatus according to the embodiment configured as described above will be explained.

This device has a vehicle height adjustment function and an attitude control function.

First, the vehicle height adjustment function that adjusts the vehicle height will be explained.

The control unit 36 includes a vehicle height sensor 34
The vehicle height detected by F and 34R is compared with the target vehicle height set in the memory of the control unit 36, and if it is determined that the vehicle height is higher than the target vehicle height, each solenoid valve 22, 23 and 26, 2
7 and exhaust solenoid valve 31,
The vehicle height is lowered. Also, control unit 3
When the vehicle height is determined to be lower than the target vehicle height, the vehicle height is raised by turning on the flow control valve 19 and the air supply solenoid valves 20 and 24.

Next, a description will be given of an attitude control function that suppresses attitude changes occurring in the vehicle body.

First, a description will be given of attitude control for suppressing squat, in which the front part of the vehicle body rises and the rear part of the vehicle body sinks due to acceleration acting on the vehicle body when the vehicle starts and accelerates. When the accelerator opening sensor 43 or the acceleration sensor 39 detects that the vehicle is rapidly accelerating, the control unit 36 turns on the air intake solenoid valve 24 for a set period of time, and also turns on the front wheel solenoid valves 22 and 23. Further, after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, a set amount of compressed air is discharged from the front wheel suspension units FS1, RS2 to the low pressure reserve tank 15b, and the rear wheel suspension units RS1, RS2 are discharged to the low pressure reserve tank 15b.
A set amount of compressed air is supplied to RS2 from the high pressure reserve tank 15a. In this way, the squat is suppressed. This state continues until the acceleration weakens. Then, the control unit 36 controls the accelerator opening sensor 42.
Alternatively, when the acceleration sensor 39 or the like detects that the sudden acceleration has weakened, the control unit 36 controls the intake solenoid valve 20 and the rear wheel solenoid valves 26 and 27 for a set period of time.
At the same time, the front wheel solenoid valves 22 and 23 are turned OFF. As a result, a set amount of compressed air is supplied from the high-pressure reserve tank 15a to the front wheel suspension units FS1 and FS2, and the rear wheel suspension units FS1 and FS2 are
A set amount of compressed air is discharged from RS1 and RS2 to the low pressure reserve tank 15b. In this way, each air spring chamber of each suspension unit S is returned to the state before the start of control.

Next, a description will be given of attitude control in the case of suppressing a nose dive in which the front portion of the vehicle body sinks due to negative acceleration acting on the vehicle body when the brake is activated.
When the brakes are applied, etc., the negative acceleration of the vehicle body is determined by differentiating the vehicle speed detected by the vehicle speed sensor 38, and if the value is greater than or equal to the set value, the control unit 36 activates the air intake solenoid valve 20. At the same time as the set time is turned on, the rear wheel solenoid valves 26 and 27 are turned on, and after the set time has elapsed, the exhaust direction switching valve 32 is turned on.
let As a result, a set amount of compressed air is supplied from the high pressure reserve tank 15a to the front wheel suspension units FS1, FS2, and a set amount of compressed air is discharged from the rear wheel suspension units RS1, RS2 to the low pressure reserve tank 15b. In this way, the nose dive is suppressed. This state is continued until the negative acceleration weakens. Then, when it is detected that the negative acceleration has weakened, the control unit 36 turns on the air intake solenoid valve 24 and the front wheel solenoid valves 22 and 23 for a set period of time, and turns on the rear wheel solenoid valve. 26, 27
Turn it off. This allows the front wheel suspension units FS1 and FS2 to connect to the low pressure reserve tank 1.
A set amount of compressed air is discharged to 5b, and a set amount of compressed air is supplied from the high pressure reserve tank 15a to the suspension units RS1 and RS2 of the rear wheels. In this way, each air spring chamber of each suspension unit S is returned to the state before the start of control.

Next, control for reducing the roll that occurs in the vehicle body when the vehicle turns will be explained with reference to the flowchart shown in FIG.

The control unit 36 first
At S1, each memory and flag are cleared to zero and the timer is also reset. Next, in step S2, the vehicle speed V is determined based on the detection signal of the vehicle speed sensor 38.
The lateral acceleration G is determined based on the detection signal of the acceleration sensor 39, and further, the steering speed θ and the steering direction D are determined based on the detection signal of the steering sensor 40, and each is stored in a predetermined memory. Further, the process proceeds to step S3, where the absolute value of the lateral acceleration G is set to the set value G0 (for example,
0.1G) or more. If it is determined ``YES'' in step S3, the process proceeds to step S4, where it is determined whether the steering is on the turning side. Here, the turning side of the steering means, for example, if leftward acceleration is acting on the vehicle body when the steering wheel 41 is steered clockwise, this means that the steering is in the turning state, and the steering wheel 41 is turned clockwise. If a rightward acceleration is applied to the vehicle body when the vehicle is steered around, it is defined as the steering being in the return state. Therefore,
The determination in step S4 is performed based on the values of the steering speed θ, the steering direction D, and the lateral acceleration.

If it is determined in step S4 as "YES", that is, that some kind of steering has started, the process proceeds to step S5, where the control time Tθ is read from the V-θ map stored in the internal memory based on the vehicle speed V and the steering speed θ.
Next, in step S6, the control time TG is read from the V-G map stored in the internal memory based on the vehicle speed V and lateral acceleration G. Here, as shown in FIG. 7, the V-θ map has control times T1, T2, T3, T4,
It is divided into multiple areas with T5 settings, and the setting time for each area is determined according to the size of the roll that will occur in the car body. Furthermore, as shown in FIG. 8, the V-G map has control times T1, T2, T3,
It is divided into multiple areas with T4 and T5 set.

Next, the process proceeds to step S7, where it is determined whether Tθ found in step S5 is larger than TG found in step S6. If the determination is ``YES'' in step S7, Tθ is stored as the control time Tc in step S8, and if the determination is ``NO'' in step S7, TG is stored as the control time Tc in step S9. After completing step S8 or S9, step
Proceeding to S10, the control time T is obtained by subtracting the control time TM already stored in a predetermined memory from the control time Tc. Note that the control time TM is the control time during which air supply and exhaust control was commanded in step A12, which will be described later.

Next, the process proceeds to step S11, where it is determined whether the control time T is greater than zero. If ``YES'' is determined in step S11, the process proceeds to step S12 and the air spring chambers 3 of the left and right suspension units S are
At the same time, a control signal is outputted to perform control to supply air to the air spring chamber 3 of the suspension unit S on the compression side for a set time and to exhaust air from the air spring chamber 3 of the suspension unit S on the extension side for a set time. Specifically, for example, when the steering direction D is clockwise, the left suspension unit FS
1. Since RS1 is on the compression side and suspension units RS2 and RS2 on the right side are on the expansion side, in this case, the right solenoid valves 23 and 27 are
When turned on, the air supply solenoid valves 20 and 24
is turned ON, and when the control time T has elapsed, a control signal is output that turns OFF the air supply solenoid valves 20 and 24 and turns ON the exhaust direction switching valves 28 and 32. Note that even after the control time T has elapsed, the right solenoid valves 23 and 27 remain ON. After outputting the control signal in step S12, the process proceeds to step S13, where the control time T is stored in a predetermined memory as the control time TM. Next, step S14
Then, the roll control flag is set to "1" in a predetermined memory, and the reversal control flag is set to "0", and a timer, which will be described in detail later, is reset. If the determination in step S11 is "NO", the process advances to step S14.

In this way, even if control is executed once in step S12, the steering speed θ, vehicle speed V, or lateral acceleration T on the turning side increases, and the control is executed in step S5.
Alternatively, if the control time Tθ or TG read in S6 increases, additional control of the control time T is performed in accordance with the increased amount, so that optimal roll control can always be performed.

On the other hand, it is "ON" in step S4, that is, the steering speed θ
If it is determined that is zero or that the steering is on the return side, the process proceeds to step S15, where it is determined whether the roll control flag is "1". If the determination in step S15 is ``NO'', the process returns to step S2, and if the determination in step S15 is ``YES'', the process proceeds to step S16 to determine whether the reversal control flag is ``1''.
If the result in step S16 is "NO", that is, it is determined that the roll control has already started but the rolling control has not been executed yet, the process proceeds to step S17, where the vehicle speed V and steering speed θ are stored in the internal memory based on the vehicle speed V and the steering speed θ. Determine whether it is within the control area of the return map. In addition,
The return map refers to the vehicle speed V as shown in Figure 9.
The control area is divided into a control area and a non-control area depending on the magnitude of the steering speed θ and the return steering speed θ. This control region is set corresponding to the vehicle speed V and the steering speed θ at which the vehicle body is likely to sway. If the determination in step S17 is ``YES'', the process proceeds to step S18, where it is determined whether the absolute value of the lateral acceleration G is greater than or equal to the set value G1. If "YES" is determined in step S18, that is, it is determined that the vehicle body will definitely roll back,
Proceeding to step S19, the reversal control is executed.

In step S19, the supply and exhaust control in the opposite direction to the supply and exhaust control commanded in step S12 is performed for a set control time.
It outputs a control signal to execute TR (for example, 0.3 seconds), starts an internal timer, sets the repeat control flag to "1", and sets the control time TM to "0". For example, if the supply and exhaust control commanded in step S12 was to supply air to the left suspension units FS1 and RS1 and exhaust air from the right suspension units FS1 and RS2, then Suspension unit FS1, RS
Exhaust from 1, right suspension unit FS
1. It supplies air to RS2. In other words, if we follow this example, just before step S19, the right solenoid valves 23 and 27 are still ON.
Although the exhaust direction switching valves 28 and 32 are ON,
In step S19, the control unit 36 includes the left solenoid valves 22, 26, the exhaust direction switching valves 28, 32, and the air supply solenoid valve 2.
Turn on 0 and 24 and then set control time
When TR has passed, the exhaust direction switching valve 28,
32 and air supply solenoid valves 20, 24.
It outputs a control signal to turn it off. In addition,
Even after the control time TR has elapsed, the left solenoid valves 22 and 26 remain ON.

After completing the process in step S19, the process proceeds to step S20.
Proceed to , and determine whether the timer has counted more than T2 (for example, 2.0 seconds). If ``YES'' is determined in step S20, the process advances to step S21 and the lateral acceleration G is determined.
It is determined whether the absolute value of is larger than the set value G3 (for example, 0.1G). If the result in step S21 is "NO", that is, the lateral acceleration G has become sufficiently small and the rolling motion has subsided, the process proceeds to step S22, where the solenoid valves 22, 23, 26 and 27, which was turned on, is turned off, and the exhaust direction switching valve 28,
32 is turned OFF, the yaw control flag is set to 0, the roll control flag is set to 0, and the timer is reset and the control time is set to 0.
Set "0" as TM. In addition, step
In S22, if the reversal control flag is already "0" immediately before the same step S22, the solenoid valves 22, 23, 26, and 27 Of these, those that were ON are controlled by duty control.
In other words, it outputs a control signal that repeats OFF and ON several times every 0.1 seconds to turn OFF.

Incidentally, when it is determined that it is "ON" in steps S17 and S18, that is, it is determined that roll control has been executed but there is no state in which rollback will occur, the process advances to step S22. If the determination in step S16 is ``YES'', the process advances to step S20, and if the determination in step S20 is ``NO'', the process returns to step S2.

On the other hand, if it is determined in step S3 that the lateral acceleration G is sufficiently small, the process proceeds to step S23.
Then, it is determined whether "1" is set as the roll control flag. If the determination in step S23 is ``NO'', the process returns to step S2, and if the determination is ``YES'', the process proceeds to step S24, in which it is determined whether the reversal control flag is set to ``1''. If it is judged as “YES” in step S24, the step
Proceed to S20, and if determined as “NO”, proceed to step S22
Proceed to.

As is clear from the above, according to this embodiment, the roll control of the vehicle body is effectively reduced based on the detection signals of the vehicle speed sensor 38, the steering sensor 40, and the acceleration sensor 39, and the rollback of the vehicle body after the roll control is also reduced. It is possible to reliably detect based on the detection signals of these sensors and effectively reduce the sway back. Moreover, since no absolute steering angle is used for control,
This has the effect of completely eliminating the problems of the conventional device described above.

〔Effect of the invention〕

As described above, according to the present invention, the roll control of the vehicle body is effectively reduced based on the detection signals of the vehicle speed sensor, the steering sensor, and the acceleration sensor. It is possible to reliably detect based on this and effectively reduce the sway back. Moreover, since no absolute steering angle is used for control, the above-mentioned problems of the conventional device can be completely eliminated.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an entire embodiment of the present invention;
2A and B are explanatory diagrams showing the operation of each three-way valve in FIG. Steering sensor 40
FIG. 5 is a perspective view showing an example of the steering sensor 4.
6 is a flowchart showing the operation of the control unit 36 in FIG. 1, FIG. 7 is a diagram showing the V-θ map set in the control unit 36, and FIG. FIG. 8 is a diagram similarly showing the V-G map, and FIG. 9 is a diagram similarly showing the return map. FS1...Left front wheel suspension unit,
FS2...Right front wheel suspension unit, RS
1...Left rear wheel suspension unit, RS2
...Right rear wheel suspension unit, 36...
Control unit, 38...Vehicle speed sensor, 3
9... Acceleration sensor, 40... Steering sensor.

Claims (1)

[Claims] 1. Left and right suspension units that support left and right wheels, respectively, and each have a fluid spring chamber, and a fluid supply device that supplies fluid to each of the fluid spring chambers through left and right wheel supply valves, respectively; A fluid discharge device that discharges fluid from each of the fluid spring chambers through the left wheel and right wheel discharge valves, respectively, and a communication control means that controls communication and isolation between the fluid spring chambers of the left and right suspension units. , a vehicle speed sensor that detects the vehicle speed, a steering sensor that detects the steering speed, and an acceleration sensor that detects the lateral acceleration acting on the vehicle body, and when it is determined that the vehicle body will roll based on the outputs of these sensors, the above-mentioned Supply/exhaust control is performed to shut off the left and right fluid spring chambers by the communication control means, and to open the supply valve of the suspension unit on the compression side and the discharge valve of the suspension unit on the extension side with respect to the roll direction for a first set time. and a control device that outputs a first control signal to be executed, wherein the control device detects that, after outputting the first control signal, the steering sensor detects that the steering is on the return side and that the steering speed is When the steering speed is equal to or higher than the first set steering speed and the acceleration sensor detects that the lateral acceleration is on the return side and the lateral acceleration is equal to or higher than the first set lateral acceleration, the communication means causes the left and right fluid to flow. A third control signal is output that causes air supply/exhaust control to be executed in the opposite direction to the roll control executed based on the first control signal for a second set time while keeping the connection between the spring chambers cut off, and then a third control signal is output.
After the set time elapses, the above lateral acceleration becomes the second
A suspension for a vehicle, characterized in that the communication control means outputs a fourth control signal for communicating between the left and right air spring chambers when it is detected that the lateral acceleration is less than the set lateral acceleration. Device.