JPH06183242A - Vehicle suspension system - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent changes in vehicle behavior due to changes in the toe angle when the supply of working fluid pressure to the fluid pressure actuator mechanism is cut off. [Structure] Actuator mechanisms 5 and 8 that can adjust the trail and toe angle by changing the positional relationship of each of the suspension constituent members 3, 4, 6, 7 and the like, and actuating hydraulic pressures are respectively supplied to these actuator mechanisms 5 and 8. In the vehicle suspension device 1 including the hydraulic circuit, the actuator mechanism 5 capable of adjusting the trail sets the absolute value of the trail to a value smaller than the standard value for trail control when the supply of the operating hydraulic pressure from the hydraulic circuit is cut off. It is configured to include a returning means for performing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device for a vehicle having a fluid pressure actuator mechanism capable of adjusting alignment according to a driving condition.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension device, a hydraulic actuator for changing the arm length of a specific suspension arm, a vehicle body mounting position, etc., a hydraulic circuit capable of supplying operating hydraulic pressure to this hydraulic actuator, and this hydraulic circuit. It is known to have a controller or the like for controlling a hydraulic actuator to control a hydraulic actuator. When the controller drives the hydraulic actuator, the positional relationship of the arms, struts, and the like that make up the suspension device changes, and therefore the alignment of the suspension device, that is, the caster angle and trail of the suspension device,
The toe angle, camber angle, etc. of the wheels change.

In this suspension device, the controller can positively operate the alignment in accordance with the running state of the vehicle to improve the straight running stability and turning stability of the vehicle. The hydraulic actuator is composed of a hydraulic cylinder mechanism, and a return means such as a spring or a rubber bush is provided between the cylinder body and the operating rod. This returning means returns the operating rod to its neutral position and holds it when the supply of the operating hydraulic pressure from the hydraulic circuit is cut off due to a failure of the controller or the like, and prevents an inadvertent change in alignment to prevent the vehicle from moving. The driving performance is secured.

[0004]

By the way, when the supply of operating oil pressure to the hydraulic actuator is cut off and the returning means returns the operating rod to its neutral position, the alignment of the suspension device changes during this returning process. In this case, in particular, the change in the toe angle has a great influence on the change in the behavior of the vehicle. Therefore, there has been a demand to suppress the influence due to the change in the toe angle.

The present invention has been made in view of the above-mentioned demands, and prevents a change in vehicle behavior due to a change in the toe angle when the supply of the working fluid pressure to the fluid pressure actuator mechanism is cut off. An object of the present invention is to provide a vehicle suspension device that can be designed.

[0006]

In order to achieve the above object, according to the present invention, first and second fluid pressures for adjusting the trail and toe angle by changing the positional relationship of each suspension component of the vehicle. In a vehicle suspension device including an actuator mechanism and a first fluid pressure supply unit that supplies a working fluid pressure to each of the fluid pressure actuator mechanisms according to a driving state of the vehicle, the first fluid pressure actuator mechanism includes (1) When the supply of the working fluid pressure from the fluid pressure supply means is cut off, there is provided a return means for setting the absolute value of the trail to a value smaller than the trail control standard value.

[0007]

In the vehicle suspension device according to the present invention, when the first fluid pressure supply means supplies the working fluid pressure to the first and second fluid pressure actuator mechanisms, these first and second fluid pressure actuator mechanisms are trailed. And adjust the toe angle. When the supply of the working fluid pressure to the first fluid pressure actuator mechanism is cut off, the resetting means sets the absolute value of the trail to a value smaller than the trail control standard value, so that the working fluid to the second fluid pressure actuator mechanism is set. Even if the supply of pressure is cut off and the toe angle changes, the change in the vehicle behavior due to the toe angle change is suppressed.

[0008]

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a suspension device to which the present invention is applied. This suspension device 1 is, for example, a double wishbone suspension device, and the left and right front wheels are connected to the vehicle body side. FIG. 1 shows, for example, a suspension device 1 that connects a left front wheel 2 to a vehicle body side (not shown). It should be noted that each suspension device 1 has the same configuration, and therefore the description and illustration of the suspension device 1 that connects the right front wheel and each rear wheel to the vehicle body side will be omitted.

The suspension device 1 includes a knuckle 3 for rotatably supporting the left front wheel 2, an upper arm 4 and an arm length variable actuator mechanism 8 for connecting an extending portion 3a of the knuckle 3 to a vehicle body (not shown), and a lower end of the knuckle 3. It is composed of a pair of lower arms 6 and 7 connected to the vehicle body side, an arm length variable actuator mechanism 5 and the like interposed between one lower arm 6 and the vehicle body side.

The variable arm length actuator mechanism 8 is an actuator mechanism for controlling the camber angle and the toe angle, and the variable arm length actuator mechanism 5 is an actuator mechanism for controlling the caster angle and the trail. Each of these arm length variable actuator mechanisms 5 and 8 includes a controller 1
0 and hydraulic circuit 40. The trail of the suspension device 1 is set to a plus predetermined distance. Therefore, sufficient restoring torque is generated around the virtual kingpin axis of the suspension device 1 to improve the straight running performance of the vehicle.

As shown in FIG. 2, the variable arm length actuator mechanism 5 for controlling the caster angle and the trail is an arm-shaped hydraulic cylinder. This actuator mechanism 5
Is an outer cylinder 12 and a pair of partition walls 1 housed in the outer cylinder 12.
3, 14 and the space between the partition walls 13, 14 are hydraulic chambers 16,
The outer cylinder 12 includes a piston 19 defined as 17, and an operating rod 21 that reciprocates integrally with the piston 19.
A return means 45 is interposed between the operating rod 21 and the operating rod 21. A mounting portion 12a is formed at the base end of the outer cylinder 12, and the mounting portion 12a is connected to a predetermined position of the vehicle body via an elastic bush. Further, the tip of the operating rod 21 is connected to the base end of the lower arm 6. Further, the displacement sensor 3 is provided between the outer cylinder 12 and the operating rod 21.
9 are provided. The displacement sensor 39 is a sensor that detects the reciprocating position of the piston 19.

Hydraulic chambers 16 and 17 of the actuator mechanism 5
The oil passages 30 and 31 of the hydraulic circuit 40 are respectively connected to. Therefore, when the working hydraulic pressure is supplied into the hydraulic chamber 16 via the oil passage 30, the oil in the hydraulic chamber 17 is removed from the oil passage 3
The piston 19 moves forward while discharging to 1, and the operating rod 2
1 is extended. On the other hand, when the working hydraulic pressure is supplied into the hydraulic chamber 17 via the oil passage 31, the piston 19 moves back and the working rod 21 retracts while discharging the oil in the hydraulic chamber 16 to the oil passage 30.

The returning means 45 is, for example, a rubber bush, and a tubular bush body 45c is interposed between the outer cylinder 45a and the inner cylinder 45b (FIG. 2). Bush body 45c
Has a predetermined wall thickness, and has an outer cylinder 45a and an inner cylinder 45.
It is vulcanized and bonded to b to be integrated. Also, the outer cylinder 45a
Is fitted to a predetermined position on the inner surface of the outer cylinder 12, and the inner cylinder 45b is fitted to a predetermined position on the outer peripheral surface of the actuating rod 21 so as to be relatively immovable.

Therefore, when the hydraulic oil is released from the hydraulic chambers 16 and 17 and the hydraulic pressure is cut off, the restoring means 45 is provided.
Returns the operating rod 21 to the small trail setting position (the position shown in FIG. 2). The small trail setting position is a predetermined position on the small trail side with respect to the neutral position of the trail control. When the operating rod 21 returns to the small trail setting position, the absolute value of the caster angle of the suspension device 1 becomes the controllable minimum value, and the trail absolute value is set to the control minimum value (minimum value in the controllable range). It

During normal running of the vehicle, the operating rod is in the neutral position for trail control, and the trail is set to the control standard value. From this state, when the vehicle is steered at a large steering angle, the operating rod is moved to the small trail side, and the absolute value of the trail decreases. Therefore, the steering operation force and the steering holding force are reduced, and the operability is improved.
On the other hand, when the vehicle speed increases from the normal traveling of the vehicle to the high-speed traveling, the operating rod is moved to the large trail side, and the absolute value of the trail increases. Therefore, the high-speed stability of the vehicle is improved.

The arm length variable actuator mechanism 8 for controlling the camber angle and the toe angle is also a hydraulic cylinder constructed in the same manner as the actuator mechanism 5 of FIG. Therefore, a detailed description and illustration of the actuator mechanism 8 will be given below.
Omit it. Each oil passage is also connected to each hydraulic chamber of the actuator mechanism 8. Then, when the supply of the operating oil pressure from each of these oil passages is cut off, the returning means of the actuator mechanism 8 returns the operating rod to the so-called neutral position.

The hydraulic circuit 40 includes a hydraulic pump, a plurality of electromagnetic control valves (both not shown), and the like. The electromagnetic control valve can connect the hydraulic pump and drain to the oil passages 30 and 31, respectively, and can switch the combination of these connections. Therefore, the electromagnetic control valve is operated by the operating rod 21.
Is hydraulically locked, extended or retracted to set the caster angle of the suspension device 1 and the toe angle and camber angle of the front wheels 2 to desired values, respectively. Here, when the caster angle is increased, the trail is also increased, and when the caster angle is decreased, the trail is also reduced. Therefore, when the caster angle is operated, the trail is operated as a result.

The electromagnetic control valve is electrically connected to the controller 10, and switches the combination of the connections according to a control signal supplied from the controller 10.
The controller 10 includes a storage device such as a ROM and a RAM (not shown), a central processing unit, an input / output device, a counter used as a timer, and the like. This controller 10
Various sensors related to the running state of the vehicle are electrically connected to the input side of the.

Further, in the storage device of the controller 10,
A predetermined alignment control routine is stored. The controller 10 repeatedly executes this alignment control routine to operate the hydraulic circuit 40, that is, the actuator mechanisms 5 and 8. As a result, the actuator mechanisms 5 and 8 appropriately expand and contract their operating rods to control the caster angle (trail), the toe angle, and the camber angle.

In this case, for example, if an abnormality occurs in the hydraulic circuit 40, the supply of operating hydraulic pressure to each actuator mechanism 5, 8 may be cut off. When the supply of operating hydraulic pressure to the hydraulic chambers 16 and 17 of the actuator mechanism 5 is cut off, the returning means 45 returns the operating rod 21 to the small trail setting position. As a result, the absolute value of the caster angle is minimized, and the absolute value of the trail is set to the minimum. By minimizing the absolute value of the caster angle, the inclination of the rotation center axis (virtual kingpin axis) of the front wheels 2 at the time of steering decreases, and thus the camber angle change amount with respect to the toe angle change decreases. Further, since the absolute value of the trail is set to the minimum, the compliance of the steering system is lowered, and therefore the followability of the vehicle behavior with respect to the transient change in the toe angle becomes dull.

Further, when the supply of operating hydraulic pressure to the hydraulic chambers of the actuator mechanism 8 is cut off, the returning means returns the operating rod to the neutral position. In the process of this return,
Although a toe angle change occurs, as described above, since the operating rod 21 of the actuator mechanism 5 returns to the small trail setting position and the absolute value of the trail is set to the minimum, the change amount of the camber angle with respect to the toe angle change is reduced. In addition, the followability of the vehicle behavior with respect to the transient toe angle change becomes dull, and the influence of the toe angle change on the vehicle behavior change becomes small.

In the present embodiment, the restoring means 45 of the actuator mechanism 5 is made of a rubber bush, but the present invention is not limited to this, and instead of the rubber bush, a restoring means is made of an elastic member such as a coil spring. 45 may be configured. Also, instead of the elastic member,
By providing an emergency hydraulic circuit of a system different from the hydraulic circuit 40, and when the hydraulic pressure from the hydraulic circuit 40 to the actuator mechanism 5 is cut off, the hydraulic pressure is supplied from this emergency hydraulic circuit to operate. The rod 21 may be returned to the small trail setting position.

[0023]

As described above, according to the present invention, in the first fluid pressure actuator mechanism for adjusting the trail of the vehicle suspension device, the supply of the working fluid pressure from the first fluid pressure supply means is cut off. In this case, the absolute value of the trail is set to a value smaller than the standard value of the trail control, and the reset means is provided. Therefore, when the supply of the working fluid pressure to the first fluid pressure actuator mechanism is cut off, the absolute value of the trail can be set to a small value, and even if the toe angle changes, the vehicle changes due to this toe angle change. There is an excellent effect that the behavior change of can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a vehicle suspension device to which the present invention is applied.

FIG. 2 is a sectional view of an arm length variable actuator mechanism of the vehicle suspension device of FIG.

[Explanation of symbols]

 1 Suspension Device 2 Front Wheels 5, 8 Arm Length Variable Actuator Mechanism 10 Controller 12 Outer Cylinder 19 Piston 21 Operating Rod 45 Returning Means

Claims (4)

[Claims] 1. A first fluid pressure actuator mechanism and a second fluid pressure actuator mechanism for adjusting a trail and a toe angle by changing a positional relationship between respective suspension constituent members of the vehicle, and these fluid pressure actuator mechanisms depending on an operating state of the vehicle. In the vehicle suspension device including the first fluid pressure supply means for supplying the respective working fluid pressures, the first fluid pressure actuator mechanism is configured such that when the supply of the working fluid pressure from the first fluid pressure supply means is cut off. A suspension device for a vehicle, comprising: return means for setting an absolute value of the trail to a value smaller than a standard value for trail control. 2. The first fluid pressure actuator mechanism,
An outer cylinder part connected to one of the vehicle body side and the wheel side, and a reciprocating part connected to the other of the vehicle body side and the wheel side and relatively movably provided in the outer cylinder part. The return means is provided between the outer cylinder portion and the reciprocating portion, and when the supply of the working fluid pressure from the first fluid pressure supplying means is cut off, the reciprocating portion is moved to the small trail setting position. The vehicle suspension device according to claim 1, further comprising an elastic member that is moved to set an absolute value of the trail to a value smaller than a trail control standard value. 3. The return means comprises second fluid pressure supply means independent of the first fluid pressure supply means, and when the supply of the working fluid pressure from the first fluid pressure supply means is cut off, the first fluid pressure supply means is provided.
3. The vehicle suspension device according to claim 1, wherein the means for supplying the working fluid pressure to the fluid pressure actuator mechanism is switched from the first fluid pressure supply means to the second fluid pressure supply means. 4. The absolute value of the trail is set to the trail control minimum value when the supply of the working fluid pressure from the first fluid pressure supply means is cut off.
The vehicle suspension device according to any one of 1.