JPH0314647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a suspension device for a vehicle that prevents posture changes such as roll (rolling) of a vehicle body.

(Prior Art) Electronically controlled suspension devices have been proposed that improve ride comfort and handling stability by electronically controlling the damping force of a shock absorber and the spring constant of an air spring. In automobiles equipped with such electronically controlled suspension devices, it is desired to more effectively prevent the occurrence of posture changes such as rolling of the automobile, thereby improving ride comfort and handling stability. ing.

(Problem to be Solved by the Invention) Therefore, as shown in US Pat. No. 3,124,368, for example, a fluid cylinder mechanism is provided for each wheel, and a control target is set according to the magnitude of acceleration acting on the vehicle body. , a suspension that reduces posture changes that occur in the vehicle body by supplying and discharging fluid to bias the cylinder mechanism on the contraction side in the direction of extension and the cylinder mechanism on the extension side in the direction of contraction in accordance with the same control target. The device is known.

However, in the device shown in this U.S. patent, the same control target is always set for the same turning situation, so even in the same turning situation, when there are many passengers on board, the control target is lower than when there are few passengers. There was a problem in that the vehicle body rolled a lot when turning, making the occupants feel uncomfortable.

This invention was made in view of the above points,
The purpose of this is to correct the control target of attitude control according to the internal pressure of the fluid spring chamber, so that the attitude control of the vehicle body is always the same regardless of the amount of passengers or cargo in response to changes in the attitude of the vehicle body caused by the vehicle's driving conditions. An object of the present invention is to provide a suspension device for a vehicle that can perform optimal posture control of feeling.

[Structure of the invention] (Means and effects for solving the problem) That is, a fluid spring chamber provided for each wheel and interposed between each wheel and the vehicle body, and a fluid spring chamber pressurized by a pressurizing device. an accumulator that stores fluid;
A supply control valve is provided for each fluid spring chamber in a supply path connecting the accumulator and each fluid spring chamber, and a supply control valve is provided for each fluid spring chamber in a discharge path for discharging fluid from each fluid spring chamber. a driving state detection means for detecting a running state of the vehicle that causes a change in the attitude of the vehicle body; A control target is set for controlling the supply control valve of the fluid spring chamber on the contraction side and the discharge control valve of the fluid spring chamber on the expansion side with respect to the direction of the attitude change, and the supply is performed in accordance with the control target. In the suspension device, the suspension device includes a pressure sensor for detecting the pressure in the fluid spring chamber, and a pressure sensor for detecting the pressure in the fluid spring chamber; control target correction means for correcting the control target according to the size, and the attitude control means is configured to execute the attitude control in accordance with the control target corrected by the control target correction means. It is something.

(Embodiment) Hereinafter, a suspension device for a vehicle according to an embodiment of the present invention will be described with reference to the drawings.
In Figure 1, S _FR indicates a suspension unit for the right front wheel of a car, S _FL indicates a suspension unit for the left front wheel, S _RR indicates a suspension unit for the right rear wheel, and S _RL indicates a suspension unit for the left rear wheel. ing. The above suspension units S _FR , S _FL , S _RR , and S _RL are the main air spring chamber 1, respectively.
1a to 11d, auxiliary air spring chambers 12a to 12d, shock absorbers 13a to 13d, and a coil spring (not shown) used as an auxiliary spring. Furthermore, 14 is a compressor as a pressurizing device. The compressor 14 compresses atmospheric air sent from an air cleaner (not shown) and supplies it to the reserve tank 17 via a check valve 15 and a dryer 16. This dryer 16 dries the supplied compressed air using silica gel or the like.

The compressed air stored in the reserve tank 17 is transferred to the main air spring chamber 11a through an air supply flow path selection solenoid valve 18a and an air supply solenoid valve 19a, which are installed in the air supply pipe _A1 .
The air is supplied to the main air spring chamber 11b via the air supply flow path selection solenoid valve 18a and the air supply solenoid valve 19b, and the air supply piping
A ₂ is connected to the main air spring chamber 11c via the air supply flow path selection solenoid valve 18b and the air supply solenoid valve 19c, and through the air supply flow path selection solenoid valve 18b and the air supply solenoid valve 19d. The air is supplied to the main air spring chamber 11d. Here, the same type of solenoid valves are used as the above-mentioned solenoid valves 18a and 18b for selecting the air supply flow path, and these valves 18a and 18b are divided into two systems, large and small, depending on whether or not the solenoid coil is excited. It is configured so that the compressed air flow path can be selected.

The compressed air in the main air spring chambers 11a to 11d is supplied to exhaust solenoid valves 20a to 20d.
and is released into the atmosphere via the exhaust pipe 21.

Further, the main air spring chambers 11a and 11b are connected via a communication solenoid valve 22a, a communication pipe B, and a communication solenoid valve 22b. The communication solenoid valve 22a also controls communication and isolation between the main air spring chamber 11a and the auxiliary air spring chamber 12a. Similarly, the communication solenoid valve 22b is connected to the main air spring chamber 11b.
It also controls communication and isolation between the air spring chamber 12b and the auxiliary air spring chamber 12b. Further, the main air spring chambers 11c and 11d are connected via a communication solenoid valve 22c, a communication pipe C, and a communication solenoid valve 22d.
The communication solenoid valve 22c also controls communication and isolation between the main air spring chamber 11c and the auxiliary air spring chamber 12c. Similarly, the communication solenoid valve 22d is connected to the main air spring chamber 11d.
It also controls communication and isolation between the air spring chamber 12d and the auxiliary air spring chamber 12d.

Note that the air supply solenoid valves 19a to 19d serve as supply control valves, and the exhaust solenoid valves 20a to 20d serve as discharge control valves.
is a valve that is always closed, and the communication solenoid valves 22a to 22d are valves that are always open.

Here, the above-mentioned solenoid valves 18a and 18b for selecting the air supply flow path are such that, for example, when the solenoid coil is energized, the large diameter flow path is closed and a small amount of compressed air is passed per unit time only through the small diameter flow path.
Further, when the magnet is not energized, the large-diameter flow path is opened, and together with the small-diameter flow path, a large amount of compressed air is passed through per unit time.

Further, 23a and 23b are pressure sensors respectively provided in the reserve tank 17,
When the internal pressure of the reserve tank 17 decreases to below the set value, the compressor 14 is activated by a signal from one pressure sensor 23a, and the reserve tank 17
When the internal pressure of the compressor 14 exceeds the set value, the compressor 14 is similarly stopped by a signal from one of the pressure sensors 23a.

The other pressure sensor 23b constantly detects the internal pressure of the reserve tank 17 and supplies the internal pressure detection signal to the controller 24. Further, 25 is a solenoid valve for draining water from the reserve tank. Furthermore, 26a to 26d are main tank pressure sensors provided in the main air spring chambers 11a to 11d, respectively, which constantly detect the internal pressure of the main air spring chambers 11a to 11d and send the internal pressure detection signal to the controller 24. supply.

By the way, each of the above solenoid valves 1
8a, 18b and 19a-19d, 20a-2
Opening/closing control of 0d, 22a to 22d, and 25 is performed by signals from the controller 24.

Furthermore, 30 is a steering sensor that detects the steering angle of the steering wheel; 31 is an acceleration sensor that detects acceleration in the longitudinal, lateral, and vertical directions of the automobile;
32 is a vehicle speed sensor that detects the vehicle speed; 33 is a front vehicle height sensor that detects the vehicle height of the front portion (front wheel portion) of the vehicle; and 34 is a rear vehicle height sensor that detects the vehicle height of the rear portion (rear wheel portion) of the vehicle. It is. Signals from each of the sensors 30 to 34 are supplied to the controller 24.

Next, the operation of an embodiment of the present invention configured as described above will be explained with reference to the flowchart of FIG. When the ignition key is turned on, the controller 24 starts the operation of the flowchart shown in FIG. First, in step S1, a predetermined memory area in the controller 24 that stores the steering wheel angle, steering wheel angular velocity, and vehicle speed is cleared to zero. Next, the process proceeds to step S2, where the map memory T _M is reset (T _M =0). Then, the process proceeds to step S3, where the controller 24 confirms that the large-diameter flow paths of the air supply flow path selection solenoid valves 18a and 18b are open, and then the process proceeds to step S4, where the communication solenoid valves 22a to 22d are opened. The controller 24 confirms that the Furthermore, the process proceeds to step S5, where the steering wheel angle detected by the steering sensor 30 is detected by the controller 24.
This steering wheel angle is read in, and the temporal change in the steering wheel angle, that is, the steering wheel angular velocity is calculated. Furthermore, the vehicle speed detected by the vehicle speed sensor 32 is input to the controller 24 .
Then, the process proceeds to step S6, where it is determined whether the above-mentioned steering wheel angle is at the neutral position. Here, when the steering wheel angle is at the neutral position, it means that the steering wheel is not being steered to the right or left. If the determination in step S6 is ``YES'', the process advances to step S7. In this step S7,
The controller 24 confirms whether the air supply solenoid valves 19a to 19d and the exhaust solenoid valves 20a to 20d are closed. Note that this step S7 is performed when these valves 19a to 19
If valves d and 20a-20d are open, close these valves.

On the other hand, if the determination in step S6 is "NO", the process advances to step S8 and subsequent steps for performing roll control. First, in step S8, the communication solenoid valves 22a to 22d are closed under the control of the controller 24. Then, the process proceeds to step S9, where it is determined whether the above-mentioned steering wheel angular velocity is equal to or greater than a reference value. If the determination in step S9 is "NO", the process advances to step S10.
In step S10, the large-diameter flow paths of the air supply flow path selection solenoid valves 18a and 18b are closed under the control of the controller 24, and only the small-diameter flow path is selected. Then, in step S11, the control time T _P , that is, the time to open the solenoid valve, is determined from the steering wheel angle-vehicle speed map shown in FIG. 3 based on the steering wheel angle and vehicle speed.
This control time T _P is determined by the region of the steering wheel angle-vehicle speed map shown in FIG. 3, and the control time T _P is written in brackets.

On the other hand, if the determination in step S9 is ``YES'', the process advances to step S12. In this step S12, the air supply flow path selection solenoid valve 1
The controller 24 confirms that the large diameter channels 8a and 18b are open, and both large and small channels are selected. Then, in step S13, the control time is calculated from the steering wheel angular velocity-vehicle speed map shown in FIG. 4 based on the above-mentioned steering wheel angular velocity and vehicle speed.
T _P , the time to open the solenoid valve, is required. This control time T _P is determined by the region of the steering wheel angular velocity-vehicle speed map shown in FIG. 4, and the control time T _P is indicated in brackets. When the processing in steps S10, S11 or S12, S13 is completed, the process proceeds to step S14, where the control time T (=T _P -T _M ) is calculated. Then, the process advances to step S15 and "T>
0” or “T≦0”. If it is determined in step S15 that "T≦0", the process returns to step S5. That is, in this case, vehicle body attitude control is not performed. On the other hand, the above step S
If it is determined in step S15 that "T>0", the process advances to step S16. In this step S16, the air supply solenoid valve 19 is
a~19d and exhaust solenoid valve 20a~
20d is controlled to open and close, thereby controlling the vehicle body attitude. For example, when the steering wheel is turned to the right, the air supply solenoid valves 19b and 19d for the left wheel are opened for the control time T under the control of the controller 24, and compressed air is supplied to the main air spring chambers 11b and 11d. . As a result, the vehicle height of the left wheel is biased in a direction to be raised. Furthermore, the exhaust solenoid valves 20a and 20c for the right wheel are opened for the above-mentioned control time T under the control of the controller 24, and the compressed air in the main air spring chambers 11a and 11c for the right wheel is released to the atmosphere. As a result, the vehicle height of the right wheel is biased in the direction of lowering. In other words,
When the steering wheel is turned to the right, the vehicle height of the left wheel is lowered, preventing the vehicle height of the right wheel from rising and keeping the vehicle level.

In this case, by selecting and setting the two systems of air supply flow paths, the solenoid valves 18a and 18b for air supply flow path selection, using the controller 24, in the case of steady turning, a relatively small amount of air supply flow rate per unit time can be used. Attitude control is performed slowly, and in the case of a sharp turn, a large amount of air supply flow per unit time allows for quick attitude control.

When the process of step S16 is completed, the process proceeds to step S17, where the map memory is updated.
In other words, T _P is set to T _M.

Further, FIG. 5 shows the solenoid valve control time T calculated in step S14 of FIG. 2 above.
, the main air spring chamber (main tank) 11a to 11
This is a flowchart for making corrections according to the internal pressure of d. When the ignition key is turned on, the controller 24 starts the operation of the flowchart shown in FIG. 5 in parallel with the flowchart shown in FIG. 2 above. be done. First, step S2
When the initial settings are completed in step S1, the process advances to step S22. In this step S22, it is determined whether or not the roll control operation after step S8 has started according to the flowchart in FIG. The roll control operation after step S8 in FIG. 2 is continued.

On the other hand, if the determination in step S22 is "NO", the process proceeds to control time correction steps starting from step S24. First, in step S24, the controller 24 receives the internal pressure detection signal P of the main air spring chambers 11a-11d from the main tank pressure sensors 26a-26d provided for each suspension unit S _FR , S _FL , S _RR , S _RL . Load. Internal pressure detection signal P in this step S24
The number of readings is accumulated in step S25. Then, in step S26, it is determined whether or not the cumulative number of times in step S25 has reached a predetermined number N.
If the determination in step S6 is "NO", the process returns to step S22.

Also, if "YES" is selected in step S26 above,
If it is determined that this is the case, the process advances to step S27. In this step S27, a pressure average value is determined from the main tank internal pressure detection signal P read by a predetermined number N in step S24. Then, in step S28, the pressure average value in step S27 is set as a control pressure value.
Compared to P _set . Here, if it is determined that ">P _set ", the process proceeds to step S29, and thereafter, the control constant T determined in the control operation shown in FIG. 2 is multiplied by the correction coefficient _K1 .

On the other hand, if it is determined in step S28 that "<P _set ", the process proceeds to step S30, whereupon the control constant T determined in the control operation shown in FIG. ₂ is multiplied by the correction coefficient K2.

When the process in step S29 or S30 is completed, the process proceeds to step S23,
When the control time (constant) T is determined in the roll control operation shown in FIG. 2, this control time T is corrected by the correction coefficient _K1 or _K2 , and the process proceeds to the next step S15.

That is, by performing the correction control operation shown in FIG. 5 above with the controller 24, compressed air is supplied to the main air spring chambers 11a to 11d to be controlled for a control time depending on the level of the internal pressure value before the control. This makes it possible to always accurately control the vehicle body posture.

Here, another example of the above-mentioned steering wheel angular velocity-vehicle speed map is shown in FIG.

(Effects of the Invention) As detailed above, according to the present invention, the running state of the vehicle that causes a change in the attitude of the vehicle is detected, and fluid is supplied to the fluid spring chamber on the contraction side in the direction of the attitude change. At the same time, by discharging the fluid from the fluid spring chamber on the extension side, it is possible to reduce the attitude change that occurs in the vehicle body, and the control target for the supply and discharge of fluid from the fluid spring chamber during the attitude control is
It is corrected according to the pressure in the fluid spring chamber, so it is corrected for changes in the posture of the vehicle body due to the vehicle's driving condition.
It is possible to provide a vehicle suspension device that can always perform optimal posture control with the same feeling regardless of the amount of passengers or cargo.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a vehicle suspension device according to an embodiment of the present invention, Fig. 2 is a flowchart showing the operation of the embodiment, and Fig. 3 is a diagram showing the steering wheel angle.
A diagram showing the vehicle speed map, Figure 4 shows the steering wheel angular velocity -
FIG. 5 is a flowchart showing the correction operation of the control time determined in the above embodiment, and FIG. 6 is a diagram showing another example of the steering wheel angular velocity-vehicle speed map. 11a-11d...main air spring chamber, 12a-12
d... Sub-air spring chamber, 17... Reserve tank, 18
a, 18b...Solenoid valve for air supply flow path selection,
19a to 19d...Air supply solenoid valve, 20
a~20d...Exhaust solenoid valve, 22a~
22d...Communication solenoid valve, 24...Controller, 26a-26d...Main tank pressure sensor, 30...Steering sensor, 32...Vehicle speed sensor.

Claims (1)

[Scope of Claims] 1. A fluid spring chamber provided for each wheel and interposed between each wheel and the vehicle body, an accumulator for storing fluid pressurized by a pressurizing device, and the above accumulator and the above. A supply control valve provided for each fluid spring chamber in a supply path connecting each fluid spring chamber, and a discharge control valve provided for each fluid spring chamber in a discharge path for discharging fluid from each fluid spring chamber. a control valve; a running state detection means for detecting a running state of the vehicle that causes a change in the attitude of the vehicle body; A control target is set for controlling the supply control valve of the fluid spring chamber on the contraction side and the discharge control valve of the fluid spring chamber on the expansion side in terms of the direction, and the supply control valve and the discharge control valve are set in accordance with the control target. A suspension device comprising a posture control means for performing posture control to control a discharge control valve, a pressure sensor for detecting the pressure in the fluid spring chamber, and a pressure sensor for detecting the pressure in the fluid spring chamber, and a suspension device according to the magnitude of the pressure detected by the pressure sensor. control target correction means for correcting the control target according to the control target correction means, and the attitude control means executes the attitude control in accordance with the control target corrected by the control target correction means. Device.