JPH0249927B2 - SHARYOYOSASUPENSHONSOCHI - 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 prevent the occurrence of rolling of the automobile and improve riding comfort and steering stability.

(Problem to be Solved by the Invention) Therefore, as shown in U.S. Pat. No. 3,124,368, for example, a fluid cylinder mechanism is provided for each wheel, and the cylinder on the contraction side is 2. Description of the Related Art Suspension devices are known that suppress changes in the attitude of a vehicle body by extending the mechanism and contracting a cylinder mechanism on the extension side. However, the device shown in this US patent uses a precise servo mechanism to control the cylinder mechanism, which not only increases costs but also requires adjustment and adjustment.
Maintenance work was also extremely difficult, making it unsuitable for use in general vehicles.

This invention was made in view of the above points,
The purpose of this is to set the control time according to the magnitude of the posture change, and also to set the supply on-off valve of the fluid spring chamber on the contraction side and the discharge on-off valve of the fluid spring chamber on the extension side for the above control time in the direction of the posture change. By opening the time, it is possible to suppress changes in the attitude of the vehicle body without using a complicated servo mechanism.Furthermore, by correcting the control time according to the internal pressure of the accumulator and the internal pressure of the fluid spring chamber, the occupant or To provide a suspension device for a vehicle that can always perform optimal vehicle body posture control with the same feeling regardless of the amount of loaded objects.

[Structure of the invention]

(Means and effects for solving the problem) That is, the vehicle suspension device according to the present invention includes a fluid spring chamber provided for each wheel and interposed between each wheel and the vehicle body, and a pressurizing device. A supply control valve is provided for each fluid spring chamber in a supply path that connects an accumulator that stores a more pressurized fluid to each of the fluid spring chambers, and a discharge valve that discharges the fluid from each fluid spring chamber. a discharge control valve provided for each fluid spring chamber in the road, an attitude change detection sensor that detects changes in the attitude of the vehicle body, and a control valve that detects changes in the attitude of the vehicle body according to the magnitude thereof when the attitude change detection sensor detects the change in attitude of the vehicle body. A suspension device comprising a control device that sets a control time and opens a supply control valve of a fluid spring chamber on a contraction side and a discharge control valve of a fluid spring chamber on an extension side for the control time in the direction of posture change. The controller further includes a first pressure sensor that detects the internal pressure of the fluid spring chamber and a second pressure sensor that detects the internal pressure of the accumulator, and the control device detects the internal pressure with the first and second pressure sensors. The control time is corrected in accordance with the internal pressures of the fluid spring chamber and the accumulator.

(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 suspension units S _FR , S _FL , S _RR , and S _RL have main air spring chambers 11a to 11d and sub air spring chambers 12a to 12, respectively.
d, 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 passes it through a check valve 15 and a dryer 16 to a reserve tank 17 as an accumulator.
is supplied to. 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 pipe _A2
Air supply flow path selection solenoid valve 18 installed in
The air is supplied to the main air spring chamber 11c via the air supply solenoid valve 19c and the air supply solenoid valve 19c, and to the main air spring chamber 11d via the air supply flow path selection solenoid valve 18b and the air supply solenoid valve 19d. 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, and when the internal pressure of the reserve tank 17 decreases to a set value or less, the compressor 14 is activated by a signal from one pressure sensor 23a. When the internal pressure of the reserve tank 17 exceeds the set value, the compressor 1 is
4 stops.

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. Further, 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, 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 the acceleration of the vehicle in the longitudinal, lateral, and vertical directions;
2 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). The process then proceeds to step S3, where the controller 24 confirms that the communication solenoid valves 22a to 22d are open. Furthermore, the steps
Proceeding to S4, the steering wheel angle detected by the steering sensor 30 is input to the controller 24, and this steering wheel angle is read, 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 . Next, proceed to step S5, and proceed to the pressure sensors 26a to 2 for the main air spring chambers (main tanks) 11a to 11d.
Pressure sensor 23 for 6d and reserve tank 17
The main air spring chambers 11a to 1 respectively detected in b
1d and the internal pressure data of the reserve tank 17 are input to the controller 24 and read. 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 it is determined as “YES” in this step S6, the step
Proceed to 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.

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, and the control time T _P , that is, the time to open the solenoid valve, is determined from the steering wheel angular velocity-vehicle speed map shown in FIG. 3 based on the above-mentioned steering wheel angular velocity and vehicle speed. This control time T _P is the third
It is determined by the area of the steering wheel angular velocity--vehicle speed map shown in the figure, and its control time T _P is written in brackets.

Next, proceed to step S10 to install the air spring chamber 11.
Based on the internal pressure values of a to 11d and the reserve tank 17, a correction coefficient K _P is determined from the main tank internal pressure-reserve tank internal pressure map shown in FIG. In other words, the main air spring chambers 11a to 11
A correction amount for the control time T _P is determined according to the level of the internal pressure of d and the level of the internal pressure of the reserve tank 17. This correction coefficient K _P is determined by K ₁ to _{K 6} in FIG. 4.

When the processes of steps S9 and S10 are completed, the process proceeds to step S11 where the control time T (=T _P × K _P −
T _M ) is calculated. Then, the process proceeds to step S12, where it is determined whether "T>0" or "T≦0". If it is determined in step S12 that "T≦0", 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 in step S12 that "T>0", the process advances to step S13. In step S13, the air supply solenoid valves 19a to 19b and the exhaust solenoid valves 20a to 20d are controlled to open and close based on the corrected control time T, 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 the main air spring chambers 11b and 11 are opened for the control time T.
Compressed air is supplied to d. As a result, the vehicle height of the left wheel is biased in a direction to be raised. Furthermore, exhaust solenoid valves 20a and 20c for the right wheel
is controlled by the controller 24 for the above control time T
The compressed air in the main air spring chambers 11a and 11c for the right wheel is opened to the atmosphere. As a result, the vehicle height of the right wheel is biased in a direction that lowers the vehicle height.
In other words, when the steering wheel is turned to the right, the height of the left wheel is lowered, preventing the height of the right wheel from rising and keeping the vehicle level.

In this case, the control time T _P obtained in step 9 is corrected by a correction coefficient K _P corresponding to the internal pressure values of the main air spring chambers 11a to 11d and the reserve tank 17, and the control time T after this correction is Since the vehicle body attitude is controlled by supplying compressed air from the reserve tank 17 to the main air spring chambers 11a to 11d, for example, the internal pressure of the main air spring chambers 11a to 11d is relatively high during attitude control, and compressed air is supplied from the reserve tank 17 to the main air spring chambers 11a to 11d. Even when it is difficult to do so, or when the internal pressure of the reserve tank 17 is relatively low, the vehicle body posture can be controlled accurately.

When the process of step S13 is completed, the process proceeds to step S14, where the map memory is updated, that is, T _P ×K _P is set in T _M.

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

〔Effect of the invention〕

As detailed above, according to the present invention, the control time is set according to the magnitude of the posture change, and the supply on/off valve for the fluid spring chamber on the contraction side and the fluid spring chamber on the expansion side are set in accordance with the magnitude of the posture change. By opening the discharge on-off valve for the above control time, it is possible to suppress changes in the attitude of the vehicle body without using a complicated servo mechanism, and furthermore, the above control time can be controlled according to the internal pressure of the accumulator and the internal pressure of the fluid spring. By correcting this, it is possible to accurately control the vehicle body attitude so that the feeling is always the same regardless of the amount of occupants 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 same embodiment, FIG. 3 is a diagram showing a steering wheel angular velocity-vehicle speed map, and FIG. This figure is a diagram showing a main tank internal pressure-reserve tank internal pressure map, and FIG. 5 is a diagram showing another example of a steering wheel angular velocity-vehicle speed map. 11a-11d...main air spring chamber, 12a-1
2d... Sub-air spring chamber, 17... Reserve tank, 18a, 18b... Air supply flow path selection solenoid valve, 19a-19d... Air supply solenoid valve, 20a-20d... Exhaust solenoid valve, 22a- 22d... Communication solenoid valve, 23a, 23b... Pressure sensor for reserve tank, 24... Controller, 26a to 26d...
...Main tank pressure sensor, 30...Steering sensor, 32...Vehicle speed sensor.

Claims (1)

[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-mentioned accumulator and each of the above-mentioned fluid spring chambers. a supply control valve provided for each fluid spring chamber in the connected supply path;
A discharge control valve provided for each fluid spring chamber in a discharge path for discharging fluid from each fluid spring chamber, an attitude change detection sensor that detects changes in the attitude of the vehicle body, and an attitude change detection sensor that detects changes in the attitude of the vehicle body. When a change is detected, a control time is set according to the magnitude thereof, and 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 extension side are controlled in the direction of the posture change. A suspension device comprising a control device for opening the suspension device, further comprising: a first pressure sensor for detecting the internal pressure of the fluid spring chamber; and a second pressure sensor for detecting the internal pressure of the accumulator; is the first and second above
A vehicle suspension device configured to correct the control time according to the internal pressures of the fluid spring chamber and the accumulator detected by a pressure sensor.