JPH0574481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a vehicle suspension device that can quickly perform roll control return control.

[Technical background of the invention and its problems] A fluid spring chamber such as an air spring chamber is interposed between the wheels and the vehicle body, and the supply and discharge of compressed air to the fluid spring chamber is controlled. A suspension device that suppresses the roll of the vehicle has been considered. For example, when turning, the suspension unit on the opposite side of the turning direction contracts, and the suspension unit on the turning direction tends to extend. It supplies compressed air and exhausts a set amount of compressed air from the fluid spring chamber of the suspension unit on the extension side to reverse the tilt of the vehicle body and keep it horizontal. For example, in the device shown in U.S. Pat. No. 2,950,124, fluid spring chambers are provided in the left and right wheels of the vehicle, and when the vehicle is traveling straight, the left and right fluid spring chambers are communicated with each other, and a steering sensor detects that the vehicle is turning. When this occurs, the vehicle body roll is reduced by blocking the left and right fluid spring chambers, supplying fluid to the fluid spring chamber on the contraction side in the roll direction of the vehicle body, and discharging fluid from the fluid spring chamber on the extension side. It is configured. This device is configured such that when the vehicle shifts from turning to straight-ahead travel, the non-communication state between the left and right fluid spring chambers is released when the steering wheel reaches its neutral position.

Therefore, when the steering wheel is suddenly returned from a certain steering angle toward its neutral position,
While the fluid spring chamber on the outside of the turn is kept at a higher pressure than the fluid spring chamber on the inside until the steering angle reaches its neutral position, the speed at which the vehicle body returns to its upright position from its roll state is also greater, so that its speed is This caused the problem that the vehicle body passed through its upright position and rolled to the opposite side, causing a so-called rollover.

[Object of the Invention] The present invention has been made in view of the above points, and its object is to use a steering sensor that detects the steering state and an acceleration sensor that detects the left-right acceleration acting on the vehicle body to determine the timing of the return control of the roll control. It is an object of the present invention to provide a vehicle suspension device that can significantly reduce the above-described rocking motion by appropriately controlling the vehicle based on the output of a sensor.

[Summary of the Invention] The present invention provides a fluid spring chamber provided for each wheel and interposed between the wheel and the vehicle body, and a fluid spring chamber discharging fluid into each fluid spring chamber through a supply/discharge control valve. A fluid supply/discharge device, a communication control device that controls communication between the left and right fluid spring chambers, a steering sensor that detects the steering state of the steering wheel, a vehicle speed sensor that detects vehicle speed, and based on the outputs of both sensors. When the cause of roll occurring in the vehicle body is detected, the system shuts off the connection between the left and right fluid spring chambers, supplies fluid to the fluid spring chamber on the contraction side in the roll direction of the vehicle body, and discharges fluid from the fluid spring chamber on the extension side. In the suspension device, the suspension device includes a control means for reducing roll of the vehicle body by outputting a control signal to the supply/discharge control valve and the communication control device,
The control means includes an acceleration sensor that detects a left-right acceleration acting on the vehicle body, and the control means reduces the acceleration acting on the vehicle body based on the direction of the acceleration detected by the acceleration sensor and a value obtained by time-differentiating the same acceleration. When it is determined that the steering wheel is in the process and the steering speed detected by the steering sensor is equal to or higher than the set operating steering speed, a control signal is output to the communication control device to cause the left and right fluid spring chambers to communicate with each other. This is a suspension device for vehicles.

[Embodiment of the Invention] An electronically controlled suspension device according to an embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, the air suspension units FS1, FS2, RS1, and RS2 each have almost the same structure, so below, they will be referred to as those for the front.
The air suspension unit will be described using the symbol S, unless specifically distinguished from the rear air suspension unit.

That is, the air suspension unit S incorporates a strut type shock absorber 1, and this shock absorber 1 is fitted into a cylinder 2 attached to the front wheel or the rear wheel side, and is slidably inserted into the cylinder 2. The cylinder 2 moves up and down with respect to the piston rod 4 in response to the up and down movement of the wheels, thereby making it possible to effectively absorb shock.
By the way, 5 is a damping force switching valve, and the rotation of this damping force switching valve 5 is controlled by an actuator 5a, and a first damping chamber 6a and a second damping chamber 6b are connected to each other.
It is selected whether the two are communicated through only orifice a1 (hard state) or through both orifices a1 and a2 (soft state). The drive of the actuator 5a is controlled by a control unit 37, which will be described later.

Incidentally, an air spring chamber 7 that also serves as a vehicle height adjustment fluid chamber is disposed coaxially with the piston rod 2 in the upper part of the shock absorber 1, and a part of this air spring chamber 7 is formed by a bellows 8. Therefore, the passage 4 provided in the piston rod 4
The piston rod 4 can be moved up and down by supplying and discharging air to and from the air spring chamber 7 through the air spring chamber 7a.

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 9a facing upward, and the outer wall of the air spring chamber 7 is provided with a spring receiver 9b facing downward.
are formed, and a coil spring 10 is loaded between these spring receivers 9a and 9b.

Thus, 11 is a compressor. This compressor 11 compresses the atmospheric air sent from the air cleaner 12 and supplies it to the dryer 13 . The compressed air dried with silica gel or the like from the dryer 13 is transferred to the reserve tank 15 via the check valve 14 . It is stored in the high pressure side reserve tank 15a. This reserve tank 1
5 is provided with a low pressure side reserve tank 15b. A compressor 16 driven by a compressor relay 17 is provided between the reserve tanks 15a and 15b. Further, a pressure switch 18 is provided which is turned on when the pressure in the low pressure side reserve tank 15b becomes higher than atmospheric pressure. When the pressure switch 18 is turned on, the compressor relay 17 is driven. As a result, the reserve tank 15b is always kept below atmospheric pressure. The route by which compressed air is supplied from the high-pressure side reserve tank 15a to the suspension unit S is indicated by a solid arrow.
In other words, the compressed air from the reserve tank 15a is supplied to the air supply flow control valve 19, which is a three-way valve (described later), the front wheel air intake solenoid valve 20, the check valve 21, the front right solenoid valve 22, and the front left solenoid valve. Front right suspension unit via 23
FS2, front left suspension unit FS
Sent to 1. Similarly, the compressed air from the reserve tank 15a is supplied to an air intake flow control valve 19 consisting of a three-way valve (to be described later), an air intake solenoid valve 24 for the rear wheels, a check valve 25, a solenoid valve 26 for the rear right, and a solenoid valve 26 for the rear left. The rear right suspension unit RS2 and the rear left suspension unit are connected to the rear right suspension unit RS2 through the solenoid valve 27.
Sent to RS1. In addition, the above check valve 2
1 and downstream of the check valve 25 are connected via a check valve 211. On the other hand, the exhaust route from the suspension unit S is indicated by a broken line arrow. In other words, the exhaust from suspension units FS1 and FS2 is from solenoid valve 2.
2, 23, front exhaust valve 28, residual pressure valve 29
The water is sent to the low pressure side reserve tank 15b via the above. Furthermore, suspension unit FS1,
Exhaust from FS2 is through solenoid valves 22, 23,
The air is released to the atmosphere via the front exhaust valve 28, the dryer 13, the exhaust solenoid valve 30, and the air cleaner 12. In addition, the exhaust from suspension units RS1 and RS2 is solenoid valve 2.
6, 27, the rear exhaust valve 31, and the residual pressure valve 32 to be sent to the low pressure side reserve tank 15b. Note that if the pressure in the reserve tank 15b is lower than the pressure in the main air spring chamber 3, the residual pressure valve 2
9 and 32 are in the open state, and the reserve tank 15b
When the pressure in the main air spring chamber 3 is greater than the pressure in the main air spring chamber 3, the residual pressure valves 29 and 32 are closed. Furthermore, the exhaust from suspension units RS1 and RS2 is controlled by solenoid valves 26 and 27, and rear exhaust valve 3.
1, dryer 13, exhaust solenoid valve 30,
It is released to the atmosphere via the air cleaner 12. Further, numeral 33 is a pressure switch provided in a communication passage communicating with the rear main air spring chamber 3, and its operation signal is outputted to a control unit to be described later.

Further, 34 is a vehicle height sensor, and this vehicle height sensor 3
Reference numeral 4 denotes a front vehicle height sensor 34F that is attached to the lower arm 35 of the front right suspension of the automobile to detect the front vehicle height of the automobile, and a front vehicle height sensor 4F that is attached to the lateral rod 36 of the rear left suspension of the automobile to detect the rear vehicle height of the automobile. Detection signals are supplied to the control unit 37 from these vehicle height sensors 34F and 34R.

Each sensor 34F, 34 in the vehicle height sensor 34
R is adapted to detect the distance from the normal vehicle height level, the low vehicle height level, or the high vehicle height level, respectively.

Furthermore, the speedometer has a built-in vehicle speed sensor 38, which detects the vehicle speed and transmits the detection signal to the control unit 3.
7.

Further, at the front end of the vehicle body, an acceleration sensor for detecting acceleration in the left and right direction, such as a differential transformer type G sensor 39, is provided as a vehicle body posture sensor for detecting changes in the posture of the vehicle body as shown in FIG. ing. The output voltage V of this G sensor 39 increases as the acceleration G increases, and an example of the output voltage is shown in FIG. 4. Further, the time differential value of the voltage V becomes a value proportional to the steering wheel angular velocity or the brake depression speed.

Reference numeral 40 is an indicator that displays the oil pressure, and the display of this indicator 40 is controlled by the control unit 37.
controlled by A steering sensor 41 detects the rotation angle of the steering wheel 42, that is, the steering angle, and its detection signal is sent to the control unit 37.

Furthermore, 44 is an accelerator opening sensor (not shown) that detects the depression angle of the accelerator pedal of the engine, and its detection signal is sent to the control unit 3.
Sent to 7. In addition, 45 is the compressor 1
This compressor relay 45 is controlled by a control signal from the control unit 37. Furthermore, 46 is a pressure switch that is turned on when the pressure in the reserve tank 15a becomes below a predetermined value, and its output signal is output to the control unit 37. In other words, when the pressure in the reserve tank 15a falls below a predetermined value, the pressure switch 46 is turned on.
Compressor relay 45 is operated under the control of control unit 37. As a result, the compressor 11 is driven and the reserve tank 15a is
Compressed air is sent to the reserve tank 15a.
The internal pressure is increased to a predetermined value or higher. Note that the solenoid valves 20, 22, 23, 24, 26, 2
7, 30 and valves 19, 28, 31 are controlled by control signals from the control unit 37. In addition, the above solenoid valve 2
2, 23, 26, 27 and valves 19, 28, 3
1 consists of a three-way valve, and its two states are shown in FIG. FIG. 2A shows a state in which the three-way valve is driven, and in this state compressed air moves along the path indicated by arrow A. On the other hand, FIG. 2B shows a state in which the three-way valve is not driven.
In this state, compressed air moves along the path indicated by arrow B. In addition, solenoid valves 20, 24, 30
is a two-way valve, and its two states are shown in FIG. FIG. 3A shows a state in which the solenoid valve is driven, and in this state compressed air moves in the direction of arrow C. On the other hand, when the solenoid valve is not driven, the situation is as shown in FIG. 3B, and in this case, there is no flow of compressed air.

Next, the operation of an embodiment of the present invention configured as described above will be explained. An overview of each control mode will be explained with reference to the valve opening/closing diagram shown in FIG. First, roll control when turning the vehicle to the right by steering the steering wheel to the right will be explained. In this case, the vehicle height of the suspension unit on the left side of the vehicle body tends to decrease, and the vehicle height of the suspension unit on the right side of the vehicle body tends to increase. Therefore, the front wheel air intake solenoid valve 20, the rear wheel air intake solenoid valve 24, the front right solenoid valve 22, and the rear right solenoid valve 26 are opened by a control signal from the control unit 37 for a set time. As a result, reserve tank 15
The compressed air stored in a is sent to the air spring chamber 7 of the front left suspension unit via the front wheel solenoid valve 20 and the front left solenoid valve 23. In addition, reserve tank 1
The compressed air stored in 5a is sent to the air spring chamber 7 of the rear left suspension unit via the rear wheel air supply solenoid valve 24 and the rear left solenoid valve 27. As a result, the left suspension unit is biased in the direction of raising the vehicle height.
On the other hand, compressed air discharged from the air spring chamber 7 of the front right suspension unit is discharged in a set amount to the reserve tank 15b via the front right solenoid valve 22 and the front exhaust valve 28. Similarly, the compressed air discharged from the air spring chamber 7 of the rear right suspension unit is discharged in a set amount to the reserve tank 15b via the rear right solenoid valve 26 and the rear exhaust valve 31. This biases the right suspension unit in a direction that lowers the vehicle height. In this way, when the vehicle turns right, the vehicle height of the left suspension unit is lowered, and the vehicle height of the right suspension unit is prevented from increasing. The above processing is the start mode, and when the start mode processing is finished, the process moves to the holding mode. In other words, the front wheel air intake solenoid valve 2
0 and rear wheel air supply solenoid valves 24 are closed. As a result, the supply of air to the air spring chamber 7 of the front left suspension unit and the rear left suspension unit is stopped. Further, the front exhaust valve 28 and the rear exhaust valve 31 are driven to stop the discharge of compressed air from the air spring chambers 7 of the front right and rear right suspension units. This maintains the roll controlled state. Then, when the right turn is completed, all valves are turned off. As a result, the air spring chambers 7 of the left and right suspension units communicate with each other via the front right solenoid valve 22 and the front left solenoid valve 23, as well as the rear right solenoid valve 26 and the rear left solenoid valve 27. Therefore, the air spring chambers 7 of the left and right suspension units are maintained at the same pressure. This releases roll control.

Next, roll control when turning the vehicle to the left by steering the steering wheel to the left will be described. In this case, the vehicle height of the suspension unit on the right side of the vehicle body tends to decrease, and the vehicle height of the suspension unit on the left side of the vehicle body tends to increase. For this reason, the front wheel air intake solenoid valve 20, the rear wheel air intake solenoid valve 24, the front left solenoid valve 23,
The rear left solenoid valve 27 is opened for a set time by a control signal from the control unit 37. As a result, the compressed air stored in the reserve tank 15a is transferred to the front wheel air supply solenoid valve 2.
0, is sent to the air spring chamber 7 of the front right suspension unit via the front right solenoid valve 22. Furthermore, the compressed air stored in the reserve tank 15a is sent to the air spring chamber 7 of the rear left suspension unit via the rear wheel air supply solenoid valve 24 and the rear right solenoid valve 26. As a result, the right suspension unit is biased in the direction of raising the vehicle height. on the other hand,
Compressed air discharged from the air spring chamber 7 of the front left suspension unit is discharged in a set amount to the reserve tank 15b via the front left solenoid valve 23 and the front exhaust valve 28. Similarly, compressed air discharged from the air spring chamber 7 of the rear left suspension unit is discharged in a set amount to the reserve tank 15b via the rear left solenoid valve 27 and the rear exhaust valve 31. This biases the left suspension unit in a direction that lowers the vehicle height. In this way, when the vehicle turns left, the vehicle height of the right suspension unit is lowered, and the vehicle height of the left suspension unit is prevented from increasing. The above processing is the start mode, and when the start mode processing is finished, the process moves to the holding mode. That is, the front wheel air intake solenoid valve 20 and the rear wheel air intake solenoid valve 24 are closed. As a result, the supply of air to the air spring chamber 7 of the front right suspension unit and the rear right suspension unit is stopped. Furthermore, the front exhaust valve 28 and the rear exhaust valve 31 are driven to stop the discharge of compressed air from the air spring chambers 7 of the front left and rear left suspension units. This maintains the roll controlled state. Then, when the left turn is completed, all valves are turned off. This results in
The air spring chambers 7 of the left and right suspension units are communicated via the front right solenoid valve 22 and the front left solenoid valve 23, as well as the rear right solenoid valve 26 and the rear left solenoid valve 27. , the air spring chambers 7 of the left and right suspension units are maintained at the same pressure. This releases roll control.

Next, nose dive control will be explained. This control prevents the front of the car from going down and the rear of the car from going up when the brakes are applied. First, as a start mode in which this nose dive is started, the front wheel air intake solenoid valve 20, the rear right solenoid valves, and the rear left solenoid valves 26 and 27 are turned on. As a result, compressed air from the reserve tank 15a is supplied to the air spring chambers 7 of the left and right front suspension units. Then, compressed air is discharged from the air spring chambers 7 of the left and right rear suspension units to the reserve tank 15b via the solenoid valves 26, 27 and the rear exhaust valve 31. After a predetermined period of time, the above-mentioned turned-on valve is turned off. As a result, air supply to the front suspension unit is stopped, and exhaust air from the rear suspension unit is also stopped. This moves to holding mode. by the way,
When the brake is no longer depressed, the control shown in the above-mentioned start mode is no longer necessary. Therefore, as a return control, the rear wheel air intake solenoid valve 24 and the front right and left solenoid valves 22 and 23 are turned on, respectively. As a result, the compressed air discharged from the air spring chambers 7 of the front right and left suspension units is transferred to the solenoid valves 22 and 2.
3. It is sent to the reserve tank 15b via the front exhaust valve 28. Also, reserve tank 1
The compressed air from 5a is supplied to the air spring chamber 7 of the rear wheel suspension unit via the rear wheel air supply solenoid valve 24 and solenoid valves 26 and 27. This returns the vehicle to the state before nose dive control.

Next, squat control will be explained. This control is designed to prevent the front of the car from rising and the rear of the car from falling when the accelerator is suddenly stepped on. First, as a start mode in which this squat control is started, the rear wheel air intake solenoid valve 24 is turned on. As a result, compressed air from the reserve tank 15a is supplied to the air spring chambers 7 of the rear left and right suspension units. As a result, the vehicle height on the rear side is raised. Then, after a predetermined period of time, the above-mentioned turned-on valve is turned off. This stops the air supply to the rear suspension unit. This moves to holding mode. By the way, when the accelerator is no longer depressed, the control shown in the above-mentioned start mode is no longer necessary. Therefore, as a return control, the front wheel air intake solenoid valve 20 and the rear right and left solenoid valves 26 and 27 are turned on, respectively. As a result, the compressed air discharged from the air spring chambers 7 of the rear right and left suspension units is sent to the reserve tank 15b via the solenoid valves 26, 27 and the rear exhaust valve 31. Further, compressed air from the reserve tank 15a is supplied to the air spring chamber 7 of the front wheel suspension unit via the front wheel air supply solenoid valve 20 and the solenoid valves 22 and 23. This returns the body to the state before squat control.

Next, a case will be described in which the vehicle height is adjusted slowly. First, the case of raising the vehicle height will be explained. In this case, the front wheel air intake solenoid valve 20 and the rear wheel air intake solenoid valve 24 are turned on, and the air intake flow rate control valve 19 is turned on. For this reason, the compressed air sent from the reserve tank 15a is supplied to the supply air flow rate control valve 19, which has a small diameter.
Air supply solenoid valves 20, 2 for front and rear wheels
4. The air is sent to the air spring chambers 7 of the suspension units on the front and rear wheels through the solenoid valves 22, 23, 26, and 27. This raises the vehicle height.

On the other hand, the case of lowering the vehicle height will be explained. In this case, the front and rear exhaust valves 28, 3
1. The exhaust solenoid valve 30 and the solenoid valves 22, 23, 26, and 27 are turned on. As a result, the compressed air discharged from the air spring chambers 7 of the front and rear suspension units is transferred to the solenoid valves 22, 23, 26, 27, the front exhaust valve 28, the rear exhaust valve 31, the dryer 13, the exhaust solenoid valve 30, It is discharged to the atmosphere via the air cleaner 12. In this case, the dryer 13 is regenerated.

Next, a case in which the vehicle height is rapidly raised will be explained. In this case, the front wheel air supply solenoid valve 2
0 and rear wheel air supply solenoid valves 24 are opened. As a result, the compressed air from the reserve tank 15a is transferred to the air spring chambers 7 of the suspension units of the front and rear wheels via the large diameter pipe of the air supply flow rate control valve 19 and the solenoid valves 22, 23, 26, and 27.
supplied to In this case, the supplied compressed air is supplied through the large-diameter pipe of the air supply flow rate control valve 19, so the amount of compressed air supplied can be increased, and the vehicle height can be adjusted rapidly. I can do it.

Next, a case will be described in which the main air spring chambers of the left and right suspension units are made non-communicating to maintain a roll-controlled state. In this case, the front exhaust valve 28 and the rear exhaust valve 31 are turned on, and the front right solenoid valve 22 and the rear right solenoid valve 26 are turned on. Due to this,
The air spring chambers 7 of the left and right suspension units are not communicated with each other.

As described above, attitude control is performed by the suspension device having the configuration shown in FIG. Next, the operation of an embodiment of the present invention configured as described above will be explained. The flowchart of FIG. 7 shows the operations performed by control unit 37. First, the vehicle speed V detected by the vehicle speed sensor 38 is read out to the control unit 37 (step S1). Then, the horizontal acceleration G output from the G sensor 39 and its differential value G〓 are read into the control unit 37 (step
S2). Further, based on the steering angle θh of the steering wheel detected by the steering sensor 41, the steering angular velocity θ·h of the steering wheel is calculated. Here, the relationships between the acceleration G in the left and right direction, the acceleration GG of the same acceleration G, the steering wheel angular velocity θ·h, and the steering wheel angle θh are shown in FIGS. 8A to 8D. As is clear from FIG. 8, the horizontal acceleration G lags behind the steering wheel angle θh by α. This is because it takes time for the vehicle body to generate acceleration after the steering wheel is turned.
Furthermore, the phase of G is 90 degrees ahead of G〓, and the phase of θh is 90 degrees ahead of θ·h.
Next, the absolute value of the steering wheel angular velocity θ・h is 30deg/
It is determined whether it is larger than sec (step S4).
In other words, it is determined whether or not the steering wheel was suddenly turned. Hereinafter, the process when the steering wheel is steered to the right will be described. If it is determined as "YES" in step S4, it is determined whether "G×θ·h" is true or not (step S5). In other words, it is determined whether the acceleration G and the handle angular velocity θ・h in the left-right direction are in the same direction. means that the steering wheel is being steered to the turning side. First, when it is determined that the handle is being steered toward the cutting side, that is, when it is determined as "YES" in step S5 above, the V-θ/h map shown in FIG. The time Tcm is determined (step S6). Then, it is determined whether the air supply valves 20, 24 are turned on (step S7). At this point, since roll control has not yet started, the determination is "NO" and the process proceeds to step S8. In this step S8, it is determined whether the air supply/exhaust time Tcm has been determined. If the supply/exhaust time Tcm is found in step S6, the determination is ``YES'' and the timer for measuring the supply/exhaust time is reset (step S9). Then, the process proceeds to step S10, where it is determined whether the front exhaust valve 28 and the rear exhaust valve 31 are on. Here, if it is on, it is turned off by a control signal from the control unit 37 (step S11). In other words, it is turned off in order to discharge exhaust gas to the low pressure reserve tank 15b when roll control is performed. In this case, since the air discharged from the air spring chamber 7 of the suspension unit is dry, there is no need to dry it with the dryer 13 when using it again.

Next, the direction of the horizontal acceleration G is detected by the control unit 37 (step S12).
That is, it is determined whether the sign of the acceleration G in the left-right direction is positive or negative. Here, if the acceleration G is positive, it is determined that the acceleration G is to the right in the direction of travel, that is, a left turn. On the other hand, if the acceleration G is negative, it is determined that the acceleration G is to the left in the direction of travel, that is, the vehicle is turning to the right. Therefore,
When it is determined that the acceleration G is to the right (left turning), the front air intake valve 20 and the rear air intake valve 24 are turned on, that is, opened (step S13).
Then, the front left solenoid valve 23 and the rear left solenoid valve 27 are turned on, that is, opened (step S14). In this way, the valve designated in the left-turn mode in FIG. 5 is driven.
On the other hand, when it is determined that the acceleration G is to the left (turning right), the front air intake valve 20 and the rear air intake valve 24 are turned on, that is, opened (step
S15). And the front right solenoid and valve 2
2 and the rear right solenoid valve 26 are turned on, that is, opened (step S15). In this way,
The designated valve is driven in the clockwise rotation mode shown in FIG. Then, it is determined whether the measured time T of the timer started in step S9 has become larger than the air supply/exhaust time Tcm (step S17).
Here, if it is determined that the measured time T is less than the above-mentioned air supply/exhaust time Tcm, the timer is counted up by cint (step S18). Thereafter, the process returns to step S1, and the processes of steps S1 to S6 are repeated. Then, in step S7, it is determined again whether the air supply valves 20 and 24 are turned on. Here, since the air supply valves 20 and 24 are turned on in step S13 or S15, the determination is "YES" and step S17 is performed.
Proceed to processing. Then, as long as the time measured by the timer is less than the supply/exhaust time Tcm, the time T is counted up in step S18, and the above step is performed.
The processes after S1 are repeated in the same way. and,
When the time measured by the timer T becomes larger than the air supply/exhaust time Tcm, the determination in step S17 is ``YES'' and the process proceeds to step S19. In step S19, the exhaust valves 28 and 31, which were turned off in step S11, are turned on. Furthermore, the air supply valves 20 and 24 are turned off (step S20). Through the processing of steps S19 and S20, the holding mode of the right turn mode or the left turn mode is executed.
In other words, the roll controlled state is maintained. Thereafter, the process returns to step S1 above.

By the way, when the steering wheel is steered in one direction and before being turned back, the steering wheel angular velocity θ·h decreases to 30 deg/sec or less. In this case, the determination in step S4 is "NO" and the process returns to step S21. And this step S21
It is determined whether G×G〓 is positive or not. here,
In the case of cutting back, "G×G〓" becomes a negative value, as is clear from FIGS. 8A and B. Then, the threshold value θ·hh is determined based on the return vehicle speed-handle angular velocity map shown in FIG. 11 (step S22). Then, it is determined whether the steering wheel angular velocity θ·h is greater than or equal to the threshold value θ·hh (step S23). If the determination in step S23 is ``YES'', the roll control is canceled in the processing from step S24 onwards. Then, in step S24, the direction of the acceleration G in the left-right direction is determined. That is, it is determined whether the sign of the acceleration G in the left-right direction is positive or negative. Here, acceleration G
If is positive, it is determined that the acceleration G is to the right in the direction of travel, that is, the vehicle is turning left. On the other hand, if the acceleration G is negative, it is determined that the acceleration G is to the left in the direction of travel, that is, the vehicle is turning to the right. Therefore, when it is determined that the acceleration G is to the right (left turning), the front left solenoid valve 23 and the rear left solenoid valve 27 are turned off, that is, closed (step S25). On the other hand, if it is determined that the acceleration G is to the left (right turn), the front right solenoid valve 22 and the rear right solenoid valve 26 are turned off, that is, closed (step S26). Then, the front air intake valve 20 and the rear air intake valve 24 are turned off, that is, closed.
(Step S27). Additionally, exhaust valves 28 and 3
1 is turned off (step S28). In this way, the roll control performed in steps S13 to S16 is canceled.

By the way, the roll control described above is performed when the steering wheel angular velocity θ・h is
This is done when the speed is greater than 30deg/sec. but,
Roll control is performed even when the steering wheel angular velocity θh is within 30 deg/sec. In other words, step
After determining "NO" in S4, it is determined whether G×G〓 is positive or not. That is, it is determined whether the acceleration G in the left-right direction and the angular velocity G are in the same direction (step S21). Here, if the determination is "YES", the air supply/exhaust time Tcm corresponding to the G level is calculated from the G sensor map shown in FIG. Thereafter, the process moves to step S7 and thereafter, and the same process as the roll control described above is performed. If the handle is turned back to the return side, step S21
The determination is "NO" and the process advances to step S22. Even if the determination in step S23 is "NO", if the determination in step S30 is "YES", the process moves to step S24 and the roll control is canceled.

In this way, by detecting G×G≦0 and performing roll control return control, the timing of roll control return control can be made suitable. Furthermore, since the G sensor 39 is provided at the front end of the vehicle body, acceleration related to the vehicle body can be quickly detected and roll control can be started and restored.

[Effects of the Invention] As detailed above, according to the present invention, when roll occurs in the vehicle body based on the vehicle speed and steering condition,
The system is configured to supply fluid to the fluid spring chamber on the compression side and discharge fluid from the fluid spring chamber on the extension side with respect to the roll direction of the vehicle body, thereby actively and sufficiently reducing the roll of the vehicle body that occurs when turning. It goes without saying that it can be done, but it also has the following effects. That is, when the steering wheel is suddenly returned from a certain steering angle toward its neutral position, and the vehicle body suddenly returns from a roll state toward its upright state,
By detecting that the lateral acceleration acting on the vehicle body is rapidly decreasing and that the steering speed is higher than the set steering speed, the system can reliably determine this and establish communication between the left and right fluid spring chambers. , even if the speed at which the vehicle body returns from its roll state to its upright state is high, the speed is not increased, and this greatly reduces the occurrence of so-called rollover, in which the vehicle body passes through its upright state and rolls to the opposite side. This can significantly improve steering stability.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an electronically controlled suspension device according to an embodiment of the present invention, and Fig. 2 A and B are 3
Figures 3A and 3B are diagrams showing the driving and non-driving states of the directional valve, Figure 4 is a diagram showing an example of the output voltage of the G sensor, and Figure 5 is a diagram showing the driving and non-driving states of the solenoid valve. Figure 6 shows the opening and closing of the valve during vehicle height adjustment and attitude control, Figure 6 shows the installation location of the G sensor, Figure 7 is a flowchart showing the operation of the same embodiment, Figure 8 shows the G, G〓, 9 is a diagram showing a steering wheel angular velocity-vehicle speed map, FIG. 10 is a diagram showing a G sensor map, 1st
FIG. 1 is a diagram showing a vehicle speed-handle angular velocity map for return control. 5a...actuator, 11...compressor,
15... Reserve tank, 19... Air supply flow rate control valve, 20... Front wheel air supply solenoid valve, 24...
Rear wheel air supply solenoid valve, 28...front exhaust valve, 31...rear exhaust valve, 37...control unit, 39...G sensor.

Claims (1)

[Claims] 1. A fluid spring chamber provided for each wheel and interposed between the wheel and the vehicle body, a fluid supply/discharge device for discharging fluid to each fluid spring chamber via a supply/discharge control valve, and a communication control device that controls communication between the fluid spring chambers of the vehicle; a steering sensor that detects the steering state of the steering wheel; and a vehicle speed sensor that detects vehicle speed; When detected, the above-mentioned supply/discharge control valve and A suspension device comprising: a control means for reducing roll of the vehicle body by outputting a control signal to the communication control device; , it is determined that the acceleration acting on the vehicle body is in the process of decreasing based on the direction of the acceleration detected by the acceleration sensor and the time-differentiated value of the acceleration, and the steering speed detected by the steering sensor is equal to or higher than the set steering speed. A vehicle suspension device that outputs a control signal to the communication control device to cause the left and right fluid spring chambers to communicate with each other when it is determined that the vehicle suspension device