JPH0360683B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronically controlled suspension device that reduces body rollback when a sudden steering is performed while driving at high speed.

[Technical background of the invention and its problems]

A suspension unit provided for each wheel and each having a fluid spring chamber, and a communication passage that connects the fluid spring chamber of the left suspension unit and the fluid spring chamber of the right suspension unit with each other via a communication control valve. When the steering angular velocity is above the set value, the communication control valve is closed and both fluids are supplied to the fluid spring chamber of the suspension unit on the sinking side, and the fluid is set from the fluid spring chamber of the suspension unit on the floating side. By discharging a large amount of fluid, the roll of the vehicle body is controlled, and when the steering angle is in the neutral range, the communication control valve is opened to lower the spring constant for each displacement of the left and right fluid spring chambers, improving ride comfort. An electronically controlled suspension device configured as follows has been considered. However, with such a device, when driving at high speed, for example, if the steering is abruptly performed in an attempt to avoid an obstacle on the road surface, and then the steering is suddenly returned again, the vehicle body may roll back, resulting in poor handling stability and ride comfort. The drawback was that it was bad.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object thereof is to provide an electronically controlled suspension device that reduces body rollback when a sudden steering is performed while driving at high speed.

[Summary of the invention]

A suspension unit provided for each wheel and each having a fluid spring chamber, and a communication passage that connects the fluid spring chamber of the left suspension unit and the fluid spring chamber of the right suspension unit with each other via a communication control valve. When the steering angular velocity is above a set value, the communication control valve is closed and a set amount of fluid is supplied to the fluid spring chamber of the suspension unit on the sinking side, and a set amount of fluid is supplied from the fluid spring chamber of the suspension unit on the floating side. Controls vehicle body roll by discharging fluid,
In a suspension device that is configured to open a communication control valve when the steering angle is in the neutral range, the spring constant for each displacement of the left and right fluid spring chambers is lowered to improve riding comfort. Yes, when the steering angle speed is high, the communication control valve is opened, and if the steering angle reaches the neutral range within a set time and the vehicle speed is higher than a predetermined value, the communication control valve is closed for the set time. In this way, the rolling of the vehicle body is reduced.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronically controlled suspension device according to an embodiment of the present invention will be described below with reference to the drawings. In Figure 1, S _FR is a suspension unit for the right front wheel of a car, S _FL is a suspension unit for the left front wheel, S _RR is a suspension unit for the right rear wheel, and S _RL is a suspension unit for the left rear wheel. . Each suspension unit
Since S _FR , S _FL , S _RL , and S _RR have the same structure, only the structure of the suspension unit S _FL is shown. The suspension unit S _FL has an air spring 1 consisting of a main air spring chamber 11 and a sub air spring chamber 12.
0, a shock absorber 13, and a coil spring (not shown) used as an auxiliary spring. The shock absorber 13 is a damping force switching valve 1 for switching the damping force between hard and soft.
3a. 14 is the same damping force switching valve 13a
The actuator 15 is a bellows. The actuator 14 controls communication and non-communication between the main air spring chamber 11 and the auxiliary air spring chamber 12, and changes the spring constant of the air spring 10 to hard/
Software switching is also performed at the same time.

Further, 16 is an air cleaner, and the atmosphere sent from the air cleaner 16 is sent to the dryer 18 via a solenoid valve 17 for shutting off outside air. The air dried by the dryer 18 is compressed by a compressor 19 and stored in a reserve tank 21 via a check valve 20. Note that 191 is a combustor relay, and this relay 191 is controlled by a signal from a controller 36, which will be described later. And reserve tank 21
The main and auxiliary air spring chambers 11 and 12 of each suspension unit SRL to SFL are connected to the main and sub-air spring chambers 11 and 12 of each suspension unit _SRL to _SFL through the supply piping 23 in which the supply solenoid valves 221 to 224 are installed.
connected to. In addition, the suspension unit
The main and auxiliary air spring chambers 11 and 12 of the S _RL and S _RR are connected by a communication pipe 25 in which a communication solenoid valve 241 is installed, and the suspension unit
The main and auxiliary air spring chambers 11 and 12 of the S _FL and S _FR are connected by a communication pipe 26 in which a communication solenoid valve 242 is interposed. In addition, the main and sub air spring chambers 11, 1 of each suspension unit S _RL to S _FL
2 is a discharge pipe 28 in which discharge solenoid valves 271 to 274 are installed, a check valve 29;
It is released to the atmosphere via the dryer 18, solenoid valve 17, and air cleaner 16. The supply piping 23 has a solenoid valve 30 for selecting the supply side flow path.
A pipe 31 is installed in parallel with the solenoid valve 30, and when the solenoid valve 30 is closed, the reserve tank 2
Air is supplied from 1 to each suspension unit through only the small diameter passage 31a, and when the solenoid valve 30 is open, the air is supplied to each suspension unit from the reserve tank 21.
Passage 31 towards each suspension unit from
Air is supplied through both the large diameter passage 31 and the large diameter passage 31. Further, the discharge pipe 28 is provided with a pipe 33 in which a solenoid valve 32 for selecting a discharge side flow path is interposed.
are arranged in parallel, and when the solenoid valve 32 is closed, air is discharged from each suspension unit toward the dryer 18 only through the small diameter passage 33a, and when the solenoid valve 32 is open, air is discharged from each suspension unit. Air is discharged toward the dryer 18 through both the passage 33a and the large diameter passage 33. A hard/soft switching solenoid valve 34 is interposed between the supply pipe 23 and each actuator 14. Further, the pressure of the compressed air stored in the reserve tank 21 is detected by a pressure switch 35.
The detection signal is sent to the controller 36. 37
are connected to the communication pipe 25, and are connected to the main and auxiliary air spring chambers 11 of the rear wheel suspension units _SRR and _SRL .
12, and the detection signal of this pressure switch 37 is sent to the controller 36.
sent to. 38F is a front vehicle height sensor 38 that is attached to the lower arm 39 on the front right side of the vehicle and detects the front vehicle height of the vehicle;
R is a rear vehicle height sensor that is attached to a lateral rod 40 on the rear left side of the automobile and detects the rear vehicle height. These vehicle height sensors 38F, 3
The vehicle height detection signal output from 8R is input to the controller 36. In the sensors 38F and 38R, one of the Hall IC elements and magnets is attached to the wheel side, and the other to the vehicle body side, and detects the distance from the normal vehicle height level and the low vehicle height or high vehicle height level, respectively. A vehicle speed sensor 41 detects the vehicle speed, and a detection signal output from the vehicle speed sensor 41 is input to the controller 36. A steering wheel steering angle sensor 42 detects the steering angle of the steering wheel 43, and this sensor 42 outputs a steering wheel steering angle detection signal to the controller 36. Further, reference numeral 44 denotes an acceleration (G) sensor that detects acceleration acting on the vehicle body, and this acceleration sensor 44 is capable of detecting changes in vehicle body posture such as pitch, roll, and yaw on the vehicle spring. For example, when there is no acceleration, the weight is suspended, and the light from the light emitting diode is blocked by the shielding plate and does not reach the photodiode.
No acceleration is detected. Then, when acceleration acts in the front and back, left and right, or up and down directions, the weight tilts or moves, and the acceleration acting on the vehicle body is detected. Furthermore, 45 is a vehicle height selection switch that sets the vehicle height to high vehicle height (HIGH), low vehicle height (LOW), and vehicle height adjustment (AUTO).
46 is an attitude control selection switch for selecting attitude control to prevent the vehicle from rolling;
Signals from these switches 45 and 46 are input to the controller 36. A brake sensor 48 detects the depression and amount of depression of the brake, and its detection signal is input to the controller 36. 49
is an accelerator opening sensor that detects the opening of the accelerator, and an accelerator opening signal output from this sensor 49 is input to the controller 36. Reference numeral 50 denotes an engine rotation speed sensor that detects the engine rotation speed, and this sensor 50 outputs an engine rotation speed signal to the controller 36. 51 is an ignition key switch, whose operation signal is sent to controller 3.
6 is output. A gear position sensor 52 detects the gear position, and this sensor 52 outputs a gear position signal to the controller 36.

In addition, each solenoid valve 17, 221 to 22
4,271 to 274, 30, and 34 are normally closed valves, and each solenoid valve 241 and 242 is a normally open valve.

FIG. 3 shows the open/close state of each solenoid valve shown in FIG. 1 in each mode, and in the figure, ○ marks are ON, and × marks are OFF. As shown in FIGS. 3a and 3b, each solenoid valve is configured to open when it is ON (normal state) and close when it is OFF (non-energized state).

Each mode will be explained in order with reference to FIG.

In the normal mode, only the front and rear left and right communication solenoid valves 242 and 241 are controlled to open, thereby communicating the air springs 10 of the left and right suspension units, and substantially increasing the volume of the air springs 10. Therefore, the spring constant is reduced and riding comfort is improved.

In vehicle height adjustment mode, vehicle height sensors 38F and 38
The vehicle height signal detected by R is compared with the target vehicle height set by the vehicle height selection switch 45, and control is performed toward the target vehicle height. , the required discharge solenoid valves are controlled to open during the lowering control. In addition, in this vehicle height adjustment mode, the left and right communication solenoid valves 242 and 24
1 is controlled to open to maintain good riding comfort. In addition, the solenoid valve 30 for selecting the supply side flow path and the solenoid valve 32 for selecting the discharge side flow path are controlled to be closed in this vehicle height adjustment mode, and the vehicle height is adjusted slowly, giving the occupants a sense of discomfort. It is configured as follows.

The roll control includes a start mode in which a required amount of air is supplied to the air spring 10 on the sinking side in the left-right direction, and a required amount of air is exhausted from the air spring 10 on the other side, and a holding mode in which the state obtained by the start mode is maintained. It consists of a return mode in which the left and right air springs 10 are kept at the same pressure when the roll factor disappears. In the start mode, the necessary supply solenoid valves and discharge solenoid valves are controlled to be open for a set time, and the respective flow path selection solenoid valves 30 and 32 are controlled to be opened to quickly perform attitude control. In the hold mode, only the flow path selection solenoid valves are kept open, so that, for example, when the lateral acceleration acting on the vehicle body increases during cornering, the air springs 10 on one side are Although it becomes necessary to additionally perform air supply from the air spring 10 and exhaust air from the air spring 10 on the other side, this additional control can be performed as quickly as possible. In the return mode, only the left and right communication solenoid valves 241 and 242 are controlled to open, which is the same state as in the normal mode.

Braking control (nose dive control) includes a start mode in which a required amount of air is supplied to the front air spring 10 and a required amount of air is exhausted from the rear air spring 10, and a holding mode in which the state obtained by the start mode is maintained. Then, when the front no longer sinks due to braking, the required amount of air is exhausted from the front air spring 10 and the required amount of air is supplied to the rear air spring 10 to return to the state before starting the start mode. It consists of a return mode. In the start mode, the front side supply solenoid valves 223, 224 and the rear side discharge solenoid valves 271, 272 are controlled to be open for a set time, and each flow path selection solenoid valve is controlled to be opened. In the holding mode, only the flow path selection solenoid valves are kept open, similar to the roll control described above. In the return mode, the front discharge solenoid valves 273, 274 and the rear supply solenoid valves 221, 222 are controlled to open for a set time, and the flow path selection solenoid valves 30, 32 continue to be opened. Ru.

The acceleration control (scout control) includes a start mode in which a required amount of air is exhausted from the front air spring 10 and a required amount of air is supplied to the rear air spring 10;
There is a holding mode in which the state obtained in the start mode is maintained, and a required amount is exhausted from the rear air spring 10 and a required amount is supplied to the front air spring 10 when the rear no longer sinks due to acceleration. and a return mode that returns the state to the state before starting the start mode. In the start mode, the front side discharge solenoid valve 273,
274 and rear supply solenoid valve 22
1 and 222 for a set time, and also controls each flow path selection solenoid valve to open. In the holding mode, only the flow path selection solenoid valves are kept open, similar to the roll control described above. In the return mode, the front side supply solenoid valves 223, 224 and the rear side discharge solenoid valves 271, 272 are controlled to be open for a set time, and the flow path selection valves 30, 32 are kept open. Each mode shown in FIG. 2 described above is controlled according to the flowchart shown in FIG. 4 set in the controller 36.

In FIG. 4, starting with the ignition key on, first, in step A, each memory in which data and flags are stored is initialized, then in step B, the vehicle height adjustment flow is started, and in step C, the roll control flow is started. , Step D goes through the nose dive control flow, Step E goes through the scout control flow, and Step F determines whether or not the ignition key is off. If it is not off, the process returns to step B again, and if it is off, the control starts. end.

The vehicle height adjustment flow (step B) is based on the vehicle height detection signals output from each vehicle height sensor 38F and 38R and the signal output from the vehicle height selection switch 45, and performs the vehicle height adjustment control shown in FIG. Control is performed to suit the required mode.

In the roll control flow (step C), the state of lateral acceleration acting on the vehicle body is predicted or detected from the outputs of the vehicle speed sensor 41, steering wheel angle sensor 42, acceleration sensor 44, etc., and based on this, the roll control flow shown in FIG. Perform control that matches the required mode of control. In the nose dive control flow (step D), the state of longitudinal acceleration acting on the vehicle body is predicted or detected from the outputs of the acceleration sensor 44, brake sensor 48, etc., and based on this, the required mode of braking control shown in FIG. 2 is selected. Perform control to suit.

In the scout control flow (step E), the state of longitudinal acceleration acting on the vehicle body is predicted or detected from the outputs of the accelerator opening sensor 49, gear position sensor 52, vehicle speed sensor 41, etc., and based on that,
Control is performed in accordance with the required mode of acceleration control shown in FIG.

Next, the roll control flow (step C) will be explained in detail with reference to FIG. First, each data and flag is set to zero, and the power to each part is turned on (step S1). The respective data include steering wheel angle, angular velocity, vehicle speed data, etc., and the flags are flags A and B. This flag A is set to "1" for only 0.25 to 0.5 seconds after the steering wheel is suddenly turned and returned and the steering angular velocity becomes large. Also, flag B is 0.25 above
If the steering wheel is returned to neutral within ~0.5 seconds, "1" is set for only 2 seconds after the steering wheel is returned to neutral. Next, the contents of the map memory are reset, that is, the valve control time Tm is reset (step S2). And the communication solenoid valve 24
1 and 242 are confirmed to be open (step S3). This keeps the left and right air spring chambers at the same pressure. Subsequently, since the steering wheel angle (handle steering angle) and the steering wheel steering angular velocity are detected based on the steering wheel angle from the steering wheel steering angle sensor 42, the process advances to step S6. The operation will be described below assuming that the steering wheel is suddenly turned clockwise and then turned back in the opposite direction to avoid an obstacle on the road while driving at high speed. Under these circumstances, the steering wheel angle increases or decreases. Therefore, when the steering wheel deviates from the neutral range and the steering wheel angular velocity increases and the steering wheel angular velocity is no longer 0, the step is stopped.
Step 3 is determined as “NO” in S6 and S7.
Proceed to S8 processing. In step S8, it is determined whether the steering direction of the steering wheel is clockwise.
In this embodiment, since the steering wheel is initially turned clockwise, the process proceeds to step S9, where it is determined whether the steering wheel position is to the right of the neutral position. The determination in step 9 determines whether the steering wheel is on the turning side or the returning side. Here, if the steering wheel is turned counterclockwise and then turned back clockwise, the steering wheel position remains on the left side, so the determination is "NO". On the other hand, while the steering wheel is being turned clockwise, the steering wheel is on the right side of the neutral position, so the determination is ``YES'' and the processing from step S10 onwards is performed. This step
In S10, it is determined whether the steering wheel angular velocity is greater than or equal to a predetermined value. Then, if the steering wheel angular velocity is above a predetermined value, the control Tp is determined from the steering wheel angular velocity-vehicle speed map (step S11), and if the steering wheel angular velocity is smaller than the prescribed value, the control time is determined from the steering wheel angle-vehicle speed map (step S11). step
S12). Then, the control time T (Tp=Tm) is calculated (step S13). Here, since Tm is initially set to "0", T=Tp. Then, it is determined whether the above T>0 or not (step
S14). If the determination in step S14 is "NO", the process returns to step S4.
That is, in this case, vehicle body attitude control is not performed. On the other hand, if it is determined that "T>0", the control time T
Only posture is controlled. This control is performed by opening and closing the valve in the left roll (that is, right steering) start mode shown in FIG. Then, the map memory is updated, that is, Tm is set to T, that is, Tp, and the process returns to step S4. Thereafter, the control time Tp is determined again using the steering wheel angular velocity--vehicle speed map or the steering wheel angle--vehicle speed map through the processing of steps S4 to S12. Here, if the control time Tp is the same as the previous one, T = Tp - Tm (=Tp) = 0, and it is determined to be "ON" in step S14, and the mode shifts to the left roll control holding mode shown in Fig. 2. , the process returns to step S4 above. As a result, the supply and exhaust valves are opened for the control time T. If the steering wheel continues to be turned and the turning angle of the steering wheel exceeds the maximum angle, this means that the steering wheel is being operated in the return direction. In other words, when you turn the steering wheel to the right and then back to the left. Then, the process proceeds to step S8 through the processes of steps S6 and S7. Since the steering wheel is returned to the left, the determination in step S8 is "NO" and the step is
Move on to processing S17. Here, since the handle is located on the right side, the determination in step S17 is ``YES'' and the process proceeds to step S18.
In this step S18, it is determined whether the steering wheel angular velocity is large. Here, when the handle angular velocity in the return direction reaches the maximum point, the determination is ``YES'' and the process proceeds to step S19 and subsequent steps. In other words, the communication valve opening signal is output from the controller 36 and the communication solenoid valve 24
1,242 is opened (step S19). and,
Timer Ta is set to 0.25 seconds (step S20),
When timer Ta becomes zero (step S21), flag A is set to "1" (step S22).
In other words, after the handle angular velocity in the return direction reaches the maximum due to the processing of steps S18 to S22, 0.25
Flag A is set after seconds. Thereafter, the process returns to step S4 and the processes after step S4 are performed. Here, flag A is set in step S22 above.
Since this has been set, the determination in step S5 is ``YES'' and the process proceeds to step S23.
In this step S23, it is determined whether or not the timer Tb is set. If not, the timer Tb is set to, for example, 0.25 seconds (step S24). Since the process of step S26 (the process of setting flag A to zero) is not performed until timer Tb reaches zero, flag A remains set. In other words, flag A starts when the steering wheel is turned back and the steering angular velocity becomes large.
It is set for only 0.25 seconds from 0.2 seconds to 0.5 seconds. Then, when the steering wheel is returned to its original position and the steering wheel angle returns to the neutral range, a ``YES'' determination is made in step S6, and the process proceeds to step S27 and subsequent steps. In step S27, it is determined whether the flag A is set. If the determination in step S27 is ``YES'' and the vehicle speed is higher than a predetermined value (if the determination is ``YES'' in step S27a), the communication solenoid valves 241 and 242 are closed. this is,
For example, solenoid valves 241, 2 for communication for 2 seconds
42 is closed, and its time control is based on the processing from step S29 onwards. First, flag B is set to "1" (step S29). and,
If the timer Tc is not set to 2 seconds (step S30), the timer Tc is set to 2 seconds (step S31). Then, when the timer Tc becomes zero (step S32), flag B is set to zero (step S33). Here, after the flag A is reset, as long as the flag B is "1", a determination of "YES" is made in step S34, and the communication solenoid valves 241 and 242 are kept closed. In this way, from the point when the steering wheel angular velocity reaches its maximum when the steering wheel is turned and suddenly returned to the
When the steering wheel returns to neutral within 0.25 to 0.5 seconds, the communication solenoid valves 241 and 242 are closed for only 2 seconds from the time the steering wheel returns to neutral to prevent the vehicle from rolling over.

Note that if the steering wheel angular velocity when the steering wheel is turned in the return direction is not high and the vehicle speed is not high, the determination in steps S18 and S35 is "NO" and the process returns to step S2, and the communication solenoid valves 241 and 242 are turned off. is opened (step S3). This is because when the steering wheel angular velocity in the returning direction is not high and the vehicle speed is not high, the body sways when the steering wheel is returned is small, so the communication solenoid valves 241 and 242 are opened and roll control is released. .

Note that if the steering wheel angular velocity when the steering wheel is turned in the return direction is not high and the vehicle speed is high, "NO" is returned at step S18, and the step S18 is returned.
If “YES” is determined in S35, the above step is executed.
Return to S4. Therefore, the communication solenoid valves 241 and 242 are not opened. In other words, even if the steering wheel angular velocity in the returning direction is not high, if the vehicle speed is high, the body will swing back a lot when the steering wheel is returned, so the communication solenoid valve 24
1,242 will not be opened.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide an electronically controlled suspension device that can reduce the rolling of the vehicle body when sudden steering is performed while traveling at high speed.

[Brief explanation of drawings]

FIG. 1 is an overall view showing one embodiment of the present invention, and FIG.
The figure shows the open/closed state of each valve in each mode in Fig. 1, Fig. 3A shows the state when each valve shown in Fig. 1 is ON, and Fig. 3B shows each valve in the same mode. FIG. 4 is a flowchart showing the main flow of control in the embodiment described above, and FIG. 5 is a flowchart showing details of the roll control flow C in FIG. 4. 10... Air spring, 21... Reserve tank,
221-224...Air supply solenoid valve, 2
41,242...Communication solenoid valve, 27
1-274...exhaust solenoid valve, 36...
…controller.

Claims (1)

[Claims] 1 A suspension unit provided for each wheel and having a fluid spring chamber, and a fluid spring chamber of the left suspension unit and a fluid spring chamber of the right suspension unit communicate with each other via a communication control valve. When the steering angular velocity exceeds a set value, the communication control valve is closed and a set amount of fluid is supplied to the fluid spring chamber of the suspension unit on the sinking side, and the fluid is supplied from the fluid spring chamber of the suspension unit on the floating side. Vehicle body roll is controlled by discharging a set amount of fluid, and when the steering angle is in the neutral range, the communication control valve is opened to lower the spring constant for each displacement of the left and right fluid spring chambers, improving ride comfort. In a suspension device that is configured to An electronically controlled suspension device comprising means for closing the communication control valve for a set time when .