JPH0780408B2 - Vehicle anti-roll device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-roll device for a vehicle, and particularly to prevent rolling of a vehicle body by utilizing a reaction force of an accumulator connected to a shock absorber. Related to the device.

[Outline of Invention]

According to the present invention, when the switching valve of the shock absorber having the accumulator for anti-roll is switched to the communication side to release the anti-roll mode, this releasing operation is performed after the pressure in the accumulator drops. This is to prevent the vehicle body from wobbling when the anti-roll mode is released.

[Conventional technology]

In order to prevent rolling that the body leans sideways when turning,
An accumulator is provided on the shock absorber. Such an accumulator is designed to communicate with the chamber above the piston of the shock absorber.If the switching valve cuts off the communication between the upper and lower chambers during turning, the oil in the chamber above the piston will be introduced into the accumulator. As a result, the gas is compressed and the reaction force suppresses the rise of the piston. Therefore, rolling of the vehicle body is prevented by performing such a shutoff operation by the switching valve on the shock absorber toward the center of turning during turning.

FIG. 5 shows a graph of such a conventional anti-roll device. By switching the anti-roll of the left and right shock absorbers according to the steering angle of the steering wheel, the shock absorber on the turning center side is shown. It is possible to increase the internal pressure of the and prevent rolling. That is, as is clear from FIG. 5, the extension of the shock absorber on the turning center side is suppressed.

[Problems to be solved by the invention]

As shown in FIG. 5, such a conventional anti-roll device is designed to switch the anti-roll by interlocking with the steering angle of the steering wheel, and the steering angle is about ± 13.5 degrees. I was trying to switch the anti-roll. However, even if the steering angle returns to ± 13.5 degrees, the residual pressure still remains in the accumulator connected to the shock absorber, so the diagonal line in the shock absorber displacement graph in Fig. 5 Moreover, there is a problem that the shock absorber extends immediately after the anti-roll mode is released. This is because the pressure in the accumulator flows from the upper chamber of the piston through the oil passage to the lower chamber, and the hydraulic pressure in the upper chamber sharply drops. As a result, the shock absorber on the turning center side is suddenly extended and the vehicle body becomes wobbled.

The present invention has been made in view of such problems, and an object thereof is to provide an anti-roll device that prevents the vehicle body from wobbling when the anti-roll mode is released. .

[Means for solving problems]

The present invention cuts off the communication between the upper and lower chambers of the shock absorber by a switching valve, introduces the oil in the upper chamber of the shock absorber into the accumulator, and extends the shock absorber toward the center of rotation by the reaction force of the accumulator at the time of turning. In the device designed to hold down, the anti-roll mode is released by the switching valve when the pressure in the accumulator becomes a predetermined value or less, or when the expansion rate of the shock absorber is switched to the anti-roll mode. It's something I did when I returned almost.

[Action]

Therefore, when the pressure in the accumulator falls below a specified value, or when the expansion rate of the shock absorber returns to the expansion rate when switching to the anti-roll mode, the switching valve is switched to the open state and the anti-roll mode is set. Is released. Therefore, after releasing the anti-roll mode, the hydraulic pressure in the chamber above the shock absorber is suddenly reduced, the shock absorber is prevented from extending, and wobble of the vehicle body is avoided.

〔Example〕

FIG. 1 shows an anti-roll device for a vehicle according to an embodiment of the present invention, in which wheels 11 having wheels 10 on both sides support a vehicle body 12 via a suspension device. The suspension device includes a pair of left and right shock absorbers 13. A piston 14 is slidably held in the shock absorber 13, and its small hole
One-way valve 16 is provided at 15. This one way valve 16
Allows the oil to flow only from the lower chamber of the piston 14 to the upper chamber, so that the oil flow in the opposite direction is blocked.

An oil passage 17 is provided outside the shock absorber 13, and the oil passage 17 is communicated with the upper chamber by a small hole 18. The oil passage 17 is connected to the lower chamber via a switching valve 19. A reservoir 20 is provided on the side surface side of the shock absorber 13, and the reservoir 20 is connected to the lower chamber via a diaphragm 21. The reservoir
The upper opening of 20 is closed by a lid (not shown) having a ventilation hole. Further, an accumulator 22 is connected to the piston rod of the shock absorber 13, and is connected to the accumulator 22 via an oil passage 23 provided in the piston rod.

Next, a mechanism for switching the switching valve 19 will be described. The switching valves 19 on the left and right are respectively connected to the air tank 27 via electromagnetic valves 28. The opening and closing of the left and right solenoid valves 28 are controlled by the microcomputer 29. Microcomputer
29 is connected to the steering angle sensor 30 and the vehicle speed sensor 31, respectively. A pressure sensor 32 for detecting the gas pressure in the accumulator 22 is attached to the accumulator 22 and is connected to the microcomputer 29.

In the configuration described above, the switching valve 19 of the shock absorber 13 is normally opened, and the upper and lower chambers are connected by the oil passage 17. That is, the oil in the upper chamber is small hole 18, oil passage
17 and the flow through the switching valve 19 to the lower chamber, which causes the shock absorber 13 to expand. Further, the oil in the lower chamber flows into the upper chamber through the small hole 15 having the one-way valve 16, and pushes down the piston 14. This causes the shock absorber 13 to contract.

The shock absorber 13 that expands and contracts in this way is
The anti-roll operation is performed by switching the switching valve 19. That is, as shown in FIG. 2, the microcomputer 29 includes a steering angle sensor 30 and a vehicle speed sensor.
While reading the output of 31 and referring to this information with the map, or predicting and calculating the turning centripetal acceleration that occurs, if it is in the area to switch to the anti-roll mode during turning, the shock on the turning center side Microcomputer to put the absorber in anti-roll mode
The solenoid valve 28 is opened by 29, and the compressed air in the air tank 27 is supplied to the switching valve 19 to shut off the switching valve 19.

When the switching valve 19 is cut off, the communication between the upper and lower chambers by the oil passage 17 is cut off. Then, at this time, since the vehicle body pulls the piston 14 of the shock absorber 13 upward so that the turning center side floats, the pressure of the oil in the upper chamber rises, and this oil passes through the oil passage 23 and the accumulator. Filled in 22. Then, the gas in the space defined by the piston of the accumulator 22 is compressed and its pressure rises, and the accumulator 22 generates a reaction force due to the compression of this gas. By utilizing this reaction force, expansion of the shock absorber 13 on the turning center side is prevented, and anti-roll operation is achieved.

At this time, the piston 14 may move slightly upward, but at this time, oil is supplied from the reservoir 20 to the lower chamber through the squeeze 21. In addition, when the piston 14 of the shock absorber 13 is pushed downward in such an anti-roll mode, the oil in the lower chamber flows into the upper chamber through the small hole 15 having the one-way valve 16. The reservoir 20 has a role of absorbing oil corresponding to the volume of the piston rod at this time.

Next, the release of the anti-roll mode will be explained. As shown in FIG. 2, the microcomputer 29 detects whether or not the conditions for releasing the anti-roll mode are satisfied by the steering angle sensor 30 and the vehicle speed sensor 31, and Accumulator if all conditions are met
The output of the pressure sensor 32 of 22 is taken into the microcomputer 29, and it is detected whether or not the residual pressure of the gas in the accumulator 22 has disappeared, that is, whether or not the pressure has dropped to the release pressure of the anti-roll mode. And accumulator
After the residual pressure in 22 has been exhausted, an OFF signal is supplied to the solenoid valve 28, the switching valve 19 is switched to the communication side, and the anti-roll mode is released.

As described above, according to the present embodiment, even if the steering angle detected by the steering angle sensor 30 becomes ± 13.5 degrees, the anti-roll mode is not immediately released at that time, and the fourth
As shown in the figure, the anti-roll mode is released after the residual pressure in the accumulator 22 is exhausted. The pressure and displacement of the shock absorber 13 at this time are as shown in the lower graph of FIG. And as is clear from this graph, the delay action
Since the anti-roll mode is released after the pressure inside 22 drops, it is possible to prevent the shock absorber 13 from temporarily expanding during release, and to avoid the situation where the vehicle body shakes steadily. become.

By the way, if the anti-roll mode is released when the steering wheel rotation angle is ± 13.5 degrees, the residual pressure in the accumulator 22 is applied to the upper chamber via the oil passage 23. Then, due to the temporary increase in the oil pressure in the upper chamber,
8, the oil passage 17 and the switching valve 19 flow to the lower chamber, and the lowering of the hydraulic pressure in the upper chamber causes the piston 14 to move rapidly in the extending direction, which causes the vehicle body 12 to wobble. . According to the apparatus of this embodiment, such a situation can be reliably avoided as described above.

Next, a modified example of the above embodiment will be described with reference to FIG.
In the above embodiment, the gas pressure in the accumulator 22 is detected by the pressure sensor 32, and the anti-roll mode is released after the residual pressure in the accumulator 22 is exhausted, but instead of such a configuration. It is possible to release the anti-roll mode in synchronization with the detection of the extension ratio of the shock absorber 13.

In this case, the expansion ratio of the shock absorber 13 is stored by the computer 29 at the time of switching to the anti-roll mode, and when the expansion ratio of the shock absorber 13 is substantially returned to the previously stored expansion ratio after the turning operation is completed. The anti-roll mode will be released. In such a modified example, it is possible to achieve the same effects as the above-described embodiment.

〔The invention's effect〕

As described above, according to the present invention, the release of the anti-roll mode by switching the switching valve is performed when the pressure in the accumulator becomes equal to or lower than a predetermined pressure, or when the expansion rate of the shock absorber is switched to the anti-roll mode. This is done when the ratio is almost returned. Therefore, the anti-roll mode is surely released after the residual pressure in the accumulator disappears, and the wobbling of the vehicle body at the time of releasing the anti-roll mode is avoided in advance.

Since such an anti-roll mode release operation is performed in conjunction with the detection of the pressure in the accumulator or the expansion rate of the shock absorber,
Regardless of the running state or the state of the vehicle, the anti-roll mode can be reliably released after the residual pressure in the accumulator has disappeared, and the release operation is prevented when the residual pressure still remains, The anti-roll mode will not be released after an unnecessarily long time has elapsed after the residual pressure is completely exhausted.

[Brief description of drawings]

FIG. 1 is a front view showing an anti-roll device for a vehicle according to an embodiment of the present invention, FIG. 2 is a flow chart showing an anti-roll mode switching operation, and FIG. 3 is a modified anti-roll mode switching operation. FIG. 4 is a graph showing the operation of switching the anti-roll mode, and FIG. 5 is a graph showing the operation of the conventional anti-roll device. In the reference numerals used in the drawings, 13: shock absorber 14: piston 17: oil passage 19: switching valve 22: accumulator 23: oil passage 28: solenoid valve 29: microcomputer 30: steering Angle sensor 31 …… Vehicle speed sensor 32 …… It is a pressure sensor.

Claims (2)

[Claims] 1. A switching valve cuts off communication between upper and lower chambers of a shock absorber, and oil in a chamber above the shock absorber is introduced into an accumulator. At the time of turning, the reaction force of the accumulator causes the oil to move toward the center of turning. In a device adapted to suppress the expansion of a shock absorber, a means for detecting the pressure in the accumulator, a means for detecting whether or not the pressure in the accumulator becomes a predetermined value or less, and a pressure in the accumulator is a predetermined value. And a means for canceling the anti-roll mode by switching the switching valve to the communication state when the value becomes less than the value. 2. The communication between the upper and lower chambers of the shock absorber is blocked by a switching valve, and the oil in the upper chamber of the shock absorber is introduced into an accumulator, and the reaction force of the accumulator at the time of turning causes the oil on the turning center side to move. In a device adapted to suppress the expansion of a shock absorber, means for detecting the expansion ratio of the shock absorber, means for storing the expansion ratio of the shock absorber when the switching valve is switched to a shutoff state, and An anti-roll device for a vehicle, comprising: means for switching the switching valve to a communication state to release the anti-roll mode when the expansion rate of the shock absorber is substantially returned to the rate stored by the storage means.