JPS6141605A - Car suspension device - Google Patents

Abstract

PURPOSE:To augment the control stability, anti-squat and anti-lift performance for a link type suspension with an upper and lower links by installing the upper and lower links to a car frame through a lifting device which is controlled by the speed of the car. CONSTITUTION:For an ordinary travelling condition, a solenoid 31a is off, and a cylinder device 20 is not operated while its rubber bushes 5 and 5a are in their lower positions. On starting, an ''on'' signal is outputted to the solenoid 31a from an electronic circuit 32 allowing a piston 22 of the cylinder device 20 to go up, a suspension braket 6 to move through a piston rod 23 as shown by the two dots-dash line, a car frame to be raised with the rubber bushes 5 and 5a deformed, and a temporary center Pa of a swing motion to be raised. This results in the augmentation of the anti-squat performance. On braking, similarily the frame is raised resulting in the augmentation of the anti-lift performance. Thus, this configuration enables the control stability, anti-squat and anti-lift performance to be augmented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a suspension system for a vehicle, and particularly to a suspension system in which an axle is connected to a vehicle body through an upper link and a lower link arranged in the longitudinal direction of the vehicle. This invention relates to a link type suspension system.

2. Description of the Related Art This type of vehicle suspension system is known, for example, as disclosed in Service Bulletin No. 484 "Sedrick, Gloria" K, published by Nissan Motor Co., Ltd. (published June 1988). This suspension bag f111 is shown in Figure 2.
It is of a shaft type, and includes an upper bracket 3 and a lower bracket 3a that protrude vertically from the axle tube 2, and a suspension bracket 6 that protrudes vertically from the suspension bracket 6 that is attached to the vehicle body 4 via rubber 7' bushes 5, 5a. The first bracket 7 and the second bracket 7a provided are connected to the upper link 8 and the lower link 9 arranged in the longitudinal direction of the vehicle.
It is connected by . 1.0 is a wheel.

Problems to be Solved by the Invention However, in such a conventional suspension system 1, the upper link 8. Lower 9F 290 both ends mounting part position is car body 4
Because it was structured to be supported in a predetermined position against
The link geometry of both the links 8 and 9 was uniquely determined.

On the other hand, for steering stability, the lower the instantaneous rotation center P (the intersection of the extension lines of both upper and lower links 8 and 9 when viewed from the left and right direction of the vehicle) when torque is applied to the axle tube 2, the better; On the contrary, in terms of anti-lift performance during starting and anti-lift performance during braking, the higher the instantaneous rotation center P is, the better. Therefore, these steering stability, anti-scut, and anti-lift functions have contradictory elements, and the problem is that the uniquely determined link geometry cannot satisfy both functions at the same time. There was a point.

Therefore, the present invention aims to provide a vehicle adverse effect device that satisfies both the steering stability, anti-scut, and anti-lift functions by making the link geometry variable according to the vehicle running condition. purpose.

Means for Solving the Problems In order to achieve the above object, the present invention provides an axle that is connected to the vehicle body through a pair of upper and lower links arranged in the longitudinal direction of the vehicle. In the vehicle suspension system, the mounting portions of the upper link and the lower link on the vehicle body side are provided with elevating means for raising and lowering the mounting portions relative to the vehicle body, and the elevating means is moved according to the vehicle running state. It is more convenient to provide a driving control means.

With the structure described above, the vehicle suspension system of the present invention has the following effects:
Since the vehicle body side mounting portions of the upper link and the lower link can be raised and lowered by the lifting means, the link geometry is variable, and the link geometry is changed by driving the lifting means by the control means according to the vehicle running state. As a result, the instantaneous center of rotation, which is related to steering stability, anti-scut, and anti-lift, is raised and lowered.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Incidentally, in explaining this embodiment, the same components as in the conventional structure will be described with the same reference numerals.

That is, FIG. 1 shows a vehicle suspension system 1a showing an embodiment of the present invention. This suspension system is of an axle type, and an upper bracket 3 and a lower bracket 3a are integrated in the vertical direction from an axle tube 2 as an axle. K
, a rubber bush 5 at the front of the axle chain 20 vehicle.
, 5a, a suspension bracket 6 is provided which is attached to the vehicle body 4 via the suspension brackets 6 and 5a. The suspension bracket 60 has an upper 1c first bracket 7 at the rear of the vehicle.
On the other hand, a second bracket 7a is provided protruding downward from the front portion of the suspension bracket 60 of the vehicle. 8 and 9 have rubber bushings 11. at both ends, respectively. lla,
12 and 12a are provided, and the upper link 8 has the rubber bush 11 between the protruding ends of the upper bracket 3 and the first bracket 7.
．． The lower link 9 is connected to the lower bracket 3a through the rubber fringe 12, 12a of the protruding end portion rjJ of the second bracket 7a. And these upper links 8. The lower link 9 is disposed in the left and right direction of the vehicle, and is installed in a substantially horizontal direction, while the rear link 8 is installed with the front of the vehicle tilted slightly downward. The extension lines of the links 8 and 9 intersect when viewed from the left and right directions of the vehicle, and the instantaneous rotation center P of the axle is determined by this intersection. A wheel 10 is attached to an axle shaft 2aK housed in the axle tube 2, and is rotatably supported by the axle tube 2. By the way, in this embodiment, the rubber bushes 11. of the upper and lower links 8.9 are provided between the axle tube 2 and the suspension bracket 6. 11
a.12. 12a is thrown, and the suspension bracket 6 is further attached to the vehicle body 4 via rubber pushers ≧5, 5a, so that a double anti-vibration effect is exhibited, and the road vibration transmitted from the wheels 10 to the vehicle body 4 is reduced. It has a texture that allows it to be absorbed efficiently.

In this embodiment, a cylinder device 20 as a lifting means is provided between the suspension bracket 6 and the vehicle body 4, and a control device 30 is also provided to drive the cylinder device 2o depending on the vehicle running state. It is. The cylinder device 20 includes a cylinder 21 arranged in the vertical direction of the vehicle, and upper and lower chambers 21a, 21 inside this cylinder 21.
The cylinder 21 has a piston 22 spaced apart from the piston 22 and a piston rod 23 protruding downward from the piston 22. The cylinder 21 is attached to the vehicle body 4 via a rubber sheet 24 for cushioning, The rod 23 passes through the rubber sheet 24 and a through hole 25 formed in the vehicle body 4, and is fixed to the suspension bracket 6 with a nut 23a. Reference numeral 40 denotes an oil pump that supplies hydraulic pressure to the cylinder system [20 through an electromagnetic switching valve 31, which will be described later. As this oil pump 40, an oil pump for power steering can be used.

On the other hand, the control means 30 is composed of the electromagnetic switching valve 31 and an electronic circuit 32 that outputs a driving current value of the solenoid 31aKON-OFF of the electromagnetic switching valve 31 based on a detection signal of the vehicle running state. . The electromagnetic switching valve 3
Reference numeral 1 designates a two-way valve, and when an OFF signal is output to the solenoid 31a, as shown in the figure, a drain passage 43 leading to a supply passage 41 from a pump 40 and a reservoir tank 42, and a cylinder assembly [20 Retired Emperor 21a, a lower chamber 21b
A first passage 44 and a second passage 45 communicate with each other, and the same pressure acts on the upper and lower chambers 21a and 21b. Further, when the aKON signal of the solenoid 31 is output, the valve moves to the left in the figure so that the supply passage 41 is communicated with the second passage 45, and the drain passage 43 is connected to the first passage 44. The pump pressure is supplied to the lower chamber 21b.

On the other hand, an ignition signal, an accelerator signal, a brake signal, etc. are input to the electronic circuit 32 as detection signals of the vehicle running state. The ignition signal is obtained as an ON-OFF signal of the ignition switch, and the accelerator signal is obtained as the amount of depression of the accelerator pedal. These signals are used to detect acceleration at the time of starting, and a decision is made at the time of starting. Then, as a result of this determination of starting, the electronic circuit 32 transmits the solenoid 318 to the
It is busy so that an ON signal is output.

On the other hand, the brake signal is obtained as a detection signal of the amount of depression of the brake pedal or the brake fluid pressure, and a judgment on braking is made. Also, an ON signal is output to the solenoid 31a based on this braking determination.

With the above-described configuration, in the vehicle suspension system 1aK of this embodiment, the electronic circuit 32 outputs the solenoid 31aKOFF signal because the normal running state of the vehicle is outside the starting state, braking state, and braking range due to personal preference. cylinder family ff1
No 20 to 11 m force is generated. Therefore, the suspension bracket 6
It is held at the L action position, that is, the downward position, and the instantaneous rotation center P is set downward as shown. Therefore, with this link geometry, the roll steer rate is improved and the steering stability is improved.

On the other hand, when starting, the solenoid 31 a is sent from the electronic circuit 32.
The KON signal is output, and since pump pressure acts on the lower chamber 21b of the piston 22 of the cylinder device i20, an upward driving force is generated. Then, this driving force is transmitted to the suspension bracket 6 via the piston rod 23, and this suspension bracket 6 deforms the rubber bushes 5, 5a as indicated by the two-dot chain line in the figure, and is moved relative to the vehicle body 4. will be raised to And solenoid 3
While the ON signal is output to 1a, the suspension bracket 6 is kept in the raised position. In this way, when the suspension bracket 6 is raised, the upper link 8. lower link 9
The mounting portion on the vehicle body side, that is, the bushes lla and 12a are also raised, the link geometry is changed, and the instantaneous center of rotation Pa is set upward. Therefore, the anti-lift performance at the time of sudden oscillation is improved, the sinking of the rear of the vehicle body is reduced, and ride comfort is improved.

Next, when braking, the solenoid 3 is
An ON signal is output to 1a, and the instantaneous rotation center Pa is set to the upper position. Therefore, anti-lift performance during braking is improved, and lift at the rear of the vehicle is reduced.

Incidentally, it is desirable that the amount of change in the link geometry, that is, the amount of movement between the instantaneous rotation centers P and Pa, be set so that the anti-lift ratio and the anti-lift ratio are approximately 1.

Incidentally, when the vehicle is transferred to a normal running state after oscillation and braking, an OFF signal is output to the solenoid 31a. Then, the electromagnetic switching valve 31 is switched to the state shown in the figure, and the driving force generated in the cylinder device 20 disappears.
The suspension bracket 6 is lowered by the restoring force of the rubber bushes 5, 5a.

In the above embodiment, the mounting portions of the upper and lower links 8.9 on the vehicle body side are attached to the suspension bracket (6), and the suspension bracket (6) is raised and lowered by the cylinder mounting (20). However, the disclosure is not limited thereto, and a cylinder device is provided directly to the vehicle body mounting portions of the upper and lower links 8 and 9, and the vehicle body side mounting portions are raised and lowered independently by the upper and lower links 8 and 9. It can be anything.

Furthermore, from the electronic circuit 32 to the solenoid 3 of the electromagnetic switching valve 31
1a is shown in which an 0N-OFF signal is output, but the present invention is not limited to this; it is also possible to use a control valve that can perform analog hydraulic control and output a current value signal that is changed in analog to this from the electronic circuit 32. However, the instantaneous rotation centers P and Pa may be changed steplessly according to acceleration and deceleration.

Further, the elevating means is not limited to the cylinder device 20, but other means such as a link mechanism may be used, and the control means may be a mechanical type instead of an electric one.

Moreover, a signal for detecting a rough road is input to the electronic circuit 32 in addition to the signals described above, and the solenoid 31a is turned on when the road is rough.
By outputting N (!) and raising the suspension bracket 6, it is possible to raise the ground clearance of the vehicle body.Also, the driver can manually input the alcON and OFF signals of the solenoid 31 without going through the electronic circuit 32. It is also possible to output power and drive according to your preferred driving state trap.

As described in detail, the vehicle suspension system of the present invention includes:
Since the elevating means is driven in accordance with the vehicle running condition to raise and lower the mounting portions of the upper link and lower link on the vehicle body side, the instantaneous rotation center of the axle can be adjusted up and down by changing the link geometry. Therefore, during normal driving, steering stability can be improved by setting the instantaneous center of rotation in a lowered state, while when starting or braking, by setting the instantaneous center of rotation in a higher state, This has the excellent effect of improving anti-lift performance and anti-lift performance.

Furthermore, by driving the elevating means even under rough road conditions and raising the mounting portions of the upper and lower links on the vehicle body side, there is also the effect that the ground clearance of the vehicle body can be increased.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a vehicle suspension system showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part of a conventional vehicle suspension system. 1.1a... Vehicle suspension system, 2... Axle chinebe (axle), 4... Vehicle body, 8... Upper link, 9... Lower link, 10... Wheel, 20...
Cylinder device (elevating means), 30...control means, 40
...Oil pump, P, Pa...Momentary rotation center. 2 people outside

Claims (1)

[Claims] (1) In a vehicle suspension system in which an axle is connected to the vehicle body through a pair of upper and lower links arranged in the longitudinal direction of the vehicle, the upper link and lower link are mounted on the vehicle body side. A suspension system for a vehicle, characterized in that a lifting means for raising and lowering the mounting part relative to the vehicle body is provided at the part thereof, and a control means is provided for driving the lifting means in accordance with the running state of the vehicle.