JPH0712773B2 - Stabilizer control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stabilizer device for connecting between unsprung members (for example, suspension arms) on left and right wheels of an automobile.

[Prior Art] Conventionally, a stabilizer device is attached to each of the left and right suspension arms and is used as a device for reducing the tilt and sway of the vehicle during turning by connecting the movements of the left and right independent wheels. ing. That is, in the stabilizer device, when the left and right wheels are in the same suspension position, the stabilizer device is not twisted and does not affect the suspension of the two. If one of the left and right wheels overhangs the ridge or the suspension position of the left and right wheels is greatly different during turning, the torsion bar of the stabilizer device will be twisted.As a result, the reaction of the torsion bar will cause torsional elasticity in the direction to cancel this twist. The force acts to equalize the suspension positions of the left and right wheels. The function of this device is related to the rolling characteristics of the automobile and the road surface followability of the wheels, and it is difficult to achieve both at the same time. As a result of some kind of compromise, both characteristics are fixed at specific levels.

Therefore, a stabilizer device capable of adjusting the torsional elastic force according to the running state has been desired. That is, it has been desired that the torsional rigidity be reduced by placing importance on the road surface followability when going straight, and the roll characteristics should be emphasized when turning to increase the rigidity.

Conventionally, for example, as disclosed in Japanese Patent Laid-Open No. 57-66009, a hydraulic cylinder is provided at a suspension arm mounting portion of a stabilizer so that the hydraulic chambers on the cylinder extension side and the compression side are communicated with each other by a bypass passage. A check valve that opens and closes with power steering (PS) hydraulic pressure
A mechanism has been proposed in which the torsional rigidity of the entire stabilizer device is changed by the hydraulic pressure for PS.

[Problems to be Solved by the Invention] In the conventional type of this type, the sliding resistance of the piston inside the cylinder can be changed, but only by changing the torsional hardness of the stabilizer. It is not possible to perform control such as supplying pressure oil to the cylinder chamber to positively prevent rolling of the vehicle.

In view of the above circumstances, the present invention can realize appropriate control corresponding to each of turning and straight traveling, improve riding comfort, and have a simple and easy-to-install configuration in a vehicle. An object of the present invention is to provide a stabilizer control device using a hydraulic circuit.

[Means for Solving the Problems] The present invention made to achieve the above object is to provide a vehicle attitude control device for controlling a stabilizer capable of changing torsional rigidity according to expansion and contraction of a hydraulic cylinder. The hydraulic cylinder includes a piston member that divides the interior into an upper chamber and a lower chamber, and expands and contracts according to the differential pressure in the upper chamber, and further, a reservoir that stores oil to be supplied to the hydraulic cylinder of the stabilizer, A hydraulic pressure source for increasing the pressure of oil stored in the reservoir and supplying the hydraulic cylinder to the hydraulic cylinder; and a pipeline connecting the reservoir and the hydraulic pressure source to the upper chamber and the lower chamber of the hydraulic cylinder, the first position At the same time, pressure oil is introduced from the hydraulic pressure source into the upper chamber of the hydraulic cylinder, and the lower chamber of the hydraulic cylinder is connected to the reservoir. And a hydraulic pressure in the lower chamber, and at the third position, the upper chamber is connected to the reservoir, and a directional control valve for introducing pressure oil from the hydraulic pressure source into the lower chamber; An on-off valve that opens and closes a pipeline that connects the chamber and the lower chamber, and a stabilizer control device that is a control means that detects the turning state of the vehicle and drives and controls the directional control valve and the on-off valve in accordance with the detected turning state. Is the gist.

[Operation] In the present invention, the hydraulic control circuit of the hydraulic cylinder unit for variably adjusting the torsional rigidity of the stabilizer is composed of the directional control valve and the on-off valve, and the piston of the cylinder unit is controlled by switching the two valves. By setting the torsional rigidity of the stabilizer in various modes by setting it to be movable or fixed to a target stroke, it is possible to improve riding comfort and reduce roll roll during turning.

For example, when traveling straight ahead, the directional control valve is switched to the second position to maintain the hydraulic pressure in the upper chamber and the lower chamber, and the open / close valve is set to the open position. As a result, the pressure oil from the hydraulic source is not supplied to the hydraulic cylinder, while the open / close valve is in the open position, so that the upper and lower chambers of the hydraulic cylinder are in communication with each other. Therefore, in this state, the piston member can slidably move inside the cylinder, and the torsional force transmitted from the stabilizer acts directly on the piston member, so that the torsional rigidity of the stabilizer is hardly generated.

When turning, for example, when the steering angle or the vehicle speed is low, the directional control valve is switched to the second position to maintain the hydraulic pressure in the upper chamber and the lower chamber, and the open / close valve is set to the closed position.
As a result, the pressure oil from the hydraulic source is not supplied to the hydraulic cylinder, and the upper and lower chambers of the hydraulic cylinder do not communicate,
The upper and lower chambers are fixed in an oil tight state. Therefore, in this state, the hydraulic cylinder is connected to the stabilizer as a kind of rigid body, so that the torsional rigidity peculiar to the stabilizer is exerted and the traveling state of the vehicle during turning is stabilized.

On the other hand, when turning, for example, when the steering angle or the vehicle speed is high, the on-off valve is closed and the directional control valve is switched to the first position or the third position. In the first position, pressure oil is introduced into the upper chamber of the hydraulic cylinder from the hydraulic source, and pressure oil in the lower chamber of the hydraulic cylinder is discharged to the reservoir. In the third position, pressure oil is introduced into the hydraulic cylinder lower chamber from the hydraulic source, and pressure oil in the hydraulic cylinder upper chamber is discharged to the reservoir.

In this way, when the piston member is moved to the target position, the directional control valve is switched to the second position to maintain the hydraulic pressure in the upper chamber and the lower chamber, and the stabilizer is set to the contracted state or the extended state. The roll angle can be reduced by positively generating torsional rigidity.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a view showing a front portion of the vehicle. The front wheel side stabilizer 1A is rotatably supported on the vehicle body by rubber bearings 3a and 3b. One end 1a of the stabilizer 1A is connected to the strut portion (or suspension arm) 7a via the tyrod 5a.
The other end 1b is attached to the strut portion 7b via the cylinder unit 9A. Reference numerals 13a and 13b are wheels, and lower arms 15a and 15b are attached to the vehicle body through strut portions 7a and 7b. As shown in FIG. 3, in the cylinder unit 9A, a piston 9b is slidably fitted in a cylinder 9a, and the piston 9b allows the inside of the cylinder 9a to be connected to an upper chamber 9e having ports 9c and 9d and a lower chamber 9e. The chamber 9f is divided, and a rod 9g is fixed to the piston 9b, and the rod 9g is fixed to the strut portion 7b. Therefore, the stabilizer device is configured so that the torsional rigidity of the stabilizer 1A can be changed by the movement of the piston 9b of the cylinder unit 9A.

The stroke control of the cylinder unit 9A is performed by the hydraulic control device shown in FIG.

Reference numeral 20 denotes an engine, which drives a hydraulic pump 22 via an output shaft 21 thereof. The hydraulic pump 22 draws oil from the reservoir 24, and through the pipe 32, the directional control valve (4 port 3-position solenoid valve) 26 and the pipes 33 to 36, the front wheel side cylinder unit 9A and the rear wheel side cylinder unit 9B. Supply pressure oil to the power steering device via the pipes 32 and 37.
28 is also supplying pressure oil. Both cylinder units 9
The upper chamber 9e and the lower chamber 9f of A and 9B communicate with each other via an on-off valve (4-port 2-position solenoid valve) 42 and also with a reservoir 24. The rear wheel cylinder unit 9B
The throttles 31a and 31b are provided in the pipelines 34 and 36 to the rear wheel side stabilizer (not shown), which is set to have a rigidity weaker than that of the front wheel side stabilizer 1A.

A switching control signal is sent to the directional control valve 26 and the on-off valve 42 by an electronic control unit 50 including a microcomputer, and the directional control valve 26 has a first position (neutral mode) and a second position (extension mode). And the third position (reduction mode), respectively, while the on-off valve 42 is switched to the communication mode and the cutoff mode. The signal input to the electronic control unit 50 is a steering sensor 60 that detects a steering angle, a vehicle speed sensor 62 that detects a vehicle speed, a stroke sensor 64 that detects a stroke of the piston 9b of the front wheel side cylinder unit 9A, and the like. Based on this signal, a control signal is output according to a program built in the electronic control unit 50.

Next, the operation of the stabilizer control device in the actual traveling state will be described.

First, straight traveling will be described. In straight driving, the first
The direction control valve 26 in the figure is set to the neutral mode, and the on-off valve 42 is set to the communication mode (OFF state). As a result, the pressure oil from the hydraulic pump 22 is supplied only to the power steering device 28 via the conduits 32 and 37, and is not supplied to the cylinder units 9A and 9B. On the other hand, the on-off valve 42
Since they are set to the communication state (OFF state), the upper and lower chambers 9e and 9f of the cylinder units 9A and 9B communicate with each other through the conduits 33 to 36, 38 and 39. Therefore, in this mode,
The piston 9b is slidably movable in the cylinder 9a, that is, the torsional force transmitted from the stabilizer 1 directly acts as the piston 9b of the cylinder units 9A and 9B, and the torsional rigidity of the stabilizer is hardly generated. become.

Next, when turning, when the steering angle and the vehicle speed are small, the directional control valve 26 is held in the neutral mode, and the on-off valve 42 is switched to the shutoff mode (ON state). This allows the cylinder unit
Fix the pistons 9b of 9A and 9B in the oil-tight state at the neutral stroke position. Therefore, the cylinder units 9A and 9B connect the stabilizer 1A and the strut portions 7a and 7b as a kind of rigid body, so that the stabilizer 1 exhibits its own torsional rigidity to stabilize the traveling state of the vehicle during turning.

On the other hand, when turning right or left and the steering angle or vehicle speed is high, the on-off valve 42 is switched to the shutoff mode (ON state), and the directional control valve 26 is switched to the extension mode or the contraction mode. That is, in the extension mode, the pressure oil of the hydraulic pump 22 is the conduit 32 → the directional control valve 26 → the conduits 35 and 36,
The pressure oil in the upper chamber 9e is supplied to the lower chamber 9f of the cylinder units 9A and 9B via the throttle 31b, and the pressure oil in the upper chamber 9e is pipe 33, pipe 34, throttle 31a →
The directional control valve 26 is discharged to the reservoir 24 via the power steering device 28. Then, the electronic control unit 50 based on the detection value of the stroke sensor 64 switches the directional control valve 26 to the neutral mode when it is determined that the cylinder units 9A and 9B have reached the target stroke position. The piston 9b of is fixed in the extended state.

As a result, as shown in FIG. 4, torsional rigidity to the stabilizer 1 is positively generated in the vehicle, and the roll angle α of the vehicle is reduced.

On the other hand, in the reduction mode of the directional control valve 26, the pressure oil of the hydraulic pump 22 is supplied to the upper chamber 9e of the cylinder units 9A and 9B via the pipe 32 → the directional control valve 26 → the pipes 33 and 34 and the throttle 31a. The pressure oil in the lower chamber 9f is discharged to the reservoir 40 via the pipes 35 and 36, the throttle 31b → the directional control valve 26 → the pipe 37 → the power steering device 28 → the pipe 40. As in the extension mode, the directional control valve 26 is switched to the neutral mode to fix the piston 9b of the cylinder units 9A and 9B at the target stroke position, so that the stabilizer 1 is in the contracted state as shown in FIG. Is set to positively generate torsional rigidity and reduce the roll angle α.

According to the above-described embodiment, the torsional rigidity of the stabilizer can be set to various modes with a simple hydraulic circuit configuration in which the cylinder units 9A and 9B have the direction control valve 26 and the opening / closing valve 42.

[Effects of the Invention] As described above, according to the stabilizer control device of the present invention, the directional control valve that controls expansion and contraction of the stabilizer by switching to the first to third positions, and the torsional rigidity of the stabilizer by opening and closing the directional control valve. The control means drives and controls the directional control valve and the on-off valve in accordance with the detected turning state of the vehicle, so that the torsional rigidity of the stabilizer can be set to various modes. Can be set.

For example, since the expansion and contraction of the hydraulic cylinder can be held at an arbitrary position by the directional control valve and the opening / closing valve, it is possible to perform control appropriately corresponding to the turning state of the vehicle. Moreover, since the on-off valve is provided separately from the directional control valve,
The stabilizer function is not disabled while controlling the expansion and contraction of the hydraulic cylinder, so that, for example, when the left and right curves are continuous, appropriate control is continuously continued corresponding to the continuous curves. It is possible to stabilize the running condition of the vehicle.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a stabilizer control device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing a front wheel portion of a vehicle having a stabilizer device, FIG. 3 is a sectional view showing a cylinder unit, and FIG. FIG. 5 and FIG. 5 are explanatory views showing the operation of the embodiment. 1 (1A) …… Stabilizer 7a, 7b …… Strut part (wheel side member) 9A, 9B …… Cylinder unit 9a …… Cylinder 9b …… Piston 9e …… Upper chamber 9f …… Lower chamber 22 …… Hydraulic pump ( Hydraulic pressure source) 26 …… Direction control valve 42 …… Open / close valve

Claims (1)

[Claims] 1. A vehicle attitude control device for controlling a stabilizer capable of changing torsional rigidity according to expansion and contraction of a hydraulic cylinder, wherein the hydraulic cylinder includes a piston member that divides the interior into an upper chamber and a lower chamber. It expands and contracts according to the pressure difference between the upper and lower chambers, and further stores a reservoir for storing oil to be supplied to the hydraulic cylinder of the stabilizer and a hydraulic pressure to supply oil to the hydraulic cylinder by increasing the pressure of the oil stored in the reservoir. Source, a reservoir and a hydraulic source, and a pipeline connecting the upper chamber and the lower chamber of the hydraulic cylinder to each other. At a first position, pressure oil is introduced from the hydraulic source to the upper chamber of the hydraulic cylinder. In addition, the lower chamber of the hydraulic cylinder is connected to the reservoir, the hydraulic pressures of the upper chamber and the lower chamber are retained at the second position, and the upper chamber is retained at the third position. A directional control valve that is connected and that introduces pressure oil from the hydraulic source to the lower chamber, an on-off valve that opens and closes a conduit that connects the upper chamber and the lower chamber of the hydraulic cylinder, and a turning state of the vehicle. A stabilizer control device comprising: a control unit that detects and drives the directional control valve and the on-off valve according to the detected turning state.