JPS60113707A - Suspension apparatus for car - Google Patents

Abstract

PURPOSE:To reduce the low noise in a car interior and improve drive feeling by steplessly controlling the flow of working fluid between the first and the second fluid chambers formed in a vibrationproof rubber by a variable orifice, thus permitting fine control. CONSTITUTION:The front side of a suspension arm is bifurcated, and installed onto a suspension member 5 through the inner and outer bushes 4 and 4a. The bushes 4 and 4a are constituted of the inner and outer cylinders 10 and 11 and a vibrationproof rubber 12, and the arm is fixed onto the outer cylinder 11. The first and the second fluid chambers 20 and 21 are formed in the vibrationproof rubber 12, and these fluid chambers 20 and 21 communicate through a communication passage 22, and a variable orifice 24 whose diameter is steplessly varied by a controller 23 is installed into the communication passage 22, and the amount of oil flow between the fluid chambers 20 and 21 can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a suspension arm for supporting a heavy wheel oriented in the longitudinal direction of a vehicle.
fc bias, relates to a vehicle suspension system in which the front side of the suspension arm of the vehicle is attached to the vehicle body via a bushing.

Prior Art Vehicle suspension systems in this category include, for example, a trailing arm type suspension system as shown in Service Bureau Line No. 329, page 170, published by Nissan Motor Co., Ltd. on January 1, 1975. . By the way, this trailing arm type suspension system is used as a rear suspension, and the suspension arm supporting the wheel is oriented toward the rear of the vehicle mJ, and the vehicle nJ side is connected to the suspension member via a pair of inner and outer bushes. The suspension member is mounted so as to be able to swing up and down, and further, both ends of the suspension member are mounted to the vehicle body via bushings. The inner and outer bushings and the bushings of the suspension members are provided with anti-vibration rubber to absorb road vibrations transmitted from the suspension arm side to the vehicle body side. However, the anti-vibration rubber needs to exhibit such a vibration-absorbing function and a function of regulating the swinging of the suspension arm in the left-right direction of the vehicle, but these two functions are contradictory in view of the spring constant of the anti-vibration rubber. For this reason, since the spring constant of the vibration isolating rubber is set at the respective midpoints in consideration of both functions, it has become impossible to fully satisfy both functions. Therefore, when the vehicle turns, the lateral G (, EL
The suspension arm swings in the left-right direction of the vehicle due to the lateral force (acceleration acting in both left and right directions), causing a compliance steer action and oversteer, making it difficult to perform turning operations. Therefore, in the past, the
As shown in No. 7-98909, an oil chamber is provided in the anti-vibration rubber that is attached to all suspension members of the vehicle, and by controlling the hydraulic pressure inside this oil chamber, the spring constant of the anti-vibration rubber can be completely changed. 2. Description of the Related Art There is a suspension system for a vehicle that suppresses suspension arm rocking when a vehicle turns, thereby significantly reducing the occurrence of a front steering action.

However, in this vehicle suspension system, the oil pressure control in the oil chamber can be switched in two stages: ON, OFF (81iHall), and high and low housing oil pressure, so it is necessary to precisely change the vibration constant of the vibration isolating rubber. I can't do it.

Therefore, even if the lateral G determined by the vehicle speed, turning radius, etc. is small, 1, that is, the turning radius is large at low speed, when the lateral G reaches a predetermined value, the oil pressure becomes high. As a result, the spring constant of the anti-vibration rubber becomes significantly large, and there is a risk that road vibrations will be input to the vehicle body, resulting in muffled noise inside the vehicle interior or worsening ride comfort.

Purpose of the Invention In view of the conventional situation, the present invention suppresses the spring constant from increasing when unnecessary by changing the spring constant of the vibration isolating rubber steplessly, thereby reducing the muffled K
An object of the present invention is to provide a suspension system for a vehicle that can significantly reduce the amount of noise and improve riding comfort.

OBJECTS OF THE INVENTION In order to achieve the above object, the vehicle suspension system of the present invention has a vibration damping rubber of a bushing that connects a suspension arm to a vehicle body. The first and second fluid chambers are formed to be filled with working fluid, and the first and second fluid chambers are communicated through a communication passage, and an orifice diameter is variable in the communication passage depending on the running condition. 1I11 controlled by providing a barrier pull orifice, and adjusting the orifice diameter of the barrier pull orifice according to the size of the lateral G. Second
By adjusting the amount of working fluid that flows from one side of the fluid chamber to the other via the communication path, and by steplessly changing the spring constant of the vibration isolating rubber and setting it to the required spring constant each time, the vibration isolating rubber This is to ensure as much vibration absorption function as possible.

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

FIG. 1 shows a vehicle suspension system 1 showing an embodiment of the present invention.
The semi-trailing arm type is shown. That is,
This semi-trailing arm type suspension system 1 has a suspension arm 3 which is oriented in the longitudinal direction of a vehicle and supports a wheel knob 2 for attaching a wheel to the rear side of the vehicle.
This suspension arm 30 has 2 parts on the front side of the vehicle.
A pair of inner and outer bushes 4 are formed in a crotch shape and each end has a pair of inner and outer bushes.
The tooth suspension arm 3 is attached to the suspension member 5 via the arm 4a, and the rear side of the vehicle can swing vertically. - Also, a bushing mounting hole 5a is formed at the end of the suspension member 5 in the left-right direction of the vehicle, and the suspension arm (5 is configured to be mounted on a vehicle body (not shown) via a fujuro mounted in the bushing mounting hole 5a. It has become.

7 is a shock absorber, 8 is a housing that accommodates a differential gear, and 9 is a drive shaft for driving the wheels. By the way, as shown in FIG. 2, the inner and outer bushings 4, 4a are composed of an inner cylinder 10°, an outer cylinder 11, and a vibration-proof rubber 12 loaded between these inner and outer cylinders 10, 11. 11, the suspension arm 3
is fixedly installed, and the suspension member 5 is attached to a protruding bracket 15 through a shaft 13 which is inserted into the inner cylinder 10 and a nut 14.

Here, in the present invention, as shown in FIG. 3, first fluid chambers 20 are provided in the vibration isolating rubber 12 of the inner and outer bushes 4, 4a at the front and rear sides of the vehicle with respect to the bolt 13.゜A second fluid chamber 21 is formed, and these first fluid chambers 21 are formed. 2nd m, offering 20, 2
1 is completely filled with oil as a working fluid. Also,
Said 1st. The second fluid chambers 20, 21 communicate with each other via a communication path 22, and the oil in each fluid chamber 20, 21 can move from one fluid chamber to the other, and from the other fluid chamber to one fluid chamber. Further, a barrier pull orifice 24 whose orifice diameter can be changed steplessly by a controller 23 is provided in the communication path 22, as described in AiJ, No. 1. The movement of oil between the second fluid chambers 20 and 21 is controlled. The controller 23 includes a lateral G sensor 25 that acts on the vehicle and a speed sensor 26.
The vehicle speed is now input. still,
The lateral G may be determined by detecting a steering angle that determines the turning radius without using the sensor 25, and detecting the lateral Gi based on the relationship between this steering angle and the vehicle speed. If the lateral G detected in this way is large, the controller 23
The orifice diameter of the barrier pull orifice 24 is controlled in the direction of decreasing by a signal from the barrier pull orifice 24, and conversely, when the lateral G is small, the orifice diameter is controlled to become narrower.

Specifically, the orifice diameter control of the barrier pull orifice 24 is independently controlled in two stages: a high speed range and a low speed range. That is, the vehicle speed detected by the speed sensor 26, for example, BoPcIn/h, is used as a guideline value, and if it is faster than this, it is considered a high speed range, and the spring constant of the anti-vibration rubber 12 is increased to be suitable for high-speed driving to improve steering stability. is mainly taken into consideration, while if the speed is slower than the reference value in 1iiJ, it is considered a low speed range, the spring constant of the vibration isolating rubber 12 is reduced, and riding comfort is mainly taken into consideration.

Furthermore, the barrier pull orifice 24 is connected to the first fluid chamber 20: +1! The passage 22a and the communication passage 22b communicating with the second fluid chamber 21 each have a first. Second
Supply paths 27 and 27a are connected, and these first. The second supply paths 27 and 27a are connected to a reservoir tank 29 of the power steering device via a switching valve 28. The switching valve 2911'' is set to the horizontal G by the controller 23.
The switching is controlled by taking into consideration the following:
The first fluid chamber 20 or the second fluid chamber 21 on the side whose volume is expanded when a load is applied to 4a from one direction in the longitudinal direction of the vehicle.
Oil is supplied from the reservoir tank 29 to allow the fluid chamber on the side to be enlarged to be smoothly deformed.

With the above configuration, in the vehicle suspension system 1 of this embodiment, when the vehicle turns, for example, when turning to the right, lateral G acts on the vehicle, and the anti-vibration rubber 12 of the inner bushing 4 moves forward of the vehicle with respect to the bolt 13. At the same time, the vibration isolating rubber 12 of the outer bushing 4a is compressed at the rear side of the vehicle with respect to the bolt 13, and the suspension arm 3 will be swung in a direction that produces compliance steer as shown by the two-dot chain line in FIG. shall be. However, at this time, the orifice diameter of the barrier pull orifice 24 is controlled in the direction of decreasing, so that the first. Significant resistance is created to oil movement between the second flow chambers 20,21. Then, the oil is the first. The second fluid chambers 20 and 21 are almost sealed inside, and the vibration-proof rubber 12's spring constant is reduced.
, 4a deformation can be suppressed to prevent the occurrence of compliance steer as shown by the two-dot chain line in FIG. 4A. In this embodiment, the spring constant of the vibration isolating rubber 12 controlled by the barrier pull orifice 24 is drawn as the fi' characteristic line shown by C in FIG. 5, and ride comfort and steering stability are inversely proportional. Become.

By the way, in this embodiment, control by the barrier pull orifice 24 is performed independently in high speed range and low speed range, and when driving at high speed on a highway etc., the barrier pull orifice 24 is controlled by #). The amount is set large,
The orifice diameter changes within the range of this setting. Therefore, the spring constants of the 11 swinging rubbers 12 of the inner and outer bushes 4, 4a are set to be large and within the range I in FIG. 5, and the steering stability is improved. In addition, even if the aperture nt k of the barrier pull orifice 24 is set to a large value in the high-speed range, it is variable within a predetermined range, so characteristics corresponding to the lateral G are obtained, and unnecessary road vibrations are prevented from moving toward the vehicle body. This prevents input from occurring, and improves countermeasures against muffled noise and improves riding comfort. Next, when the vehicle is traveling at low speed in a city or the like, the amount of restriction of the barrier pull orifice 24 is set to be small, and the orifice diameter is variable within this range. Then, the spring constant of the anti-vibration rubber 12 becomes smaller and is set in the range shown by ■ in FIG. 5, and steering stability with emphasis on riding comfort is obtained. Even in this case, since the barrier pull orifice 24 is variable within a predetermined radius according to the lateral G, unnecessary road vibrations are prevented from being input to the vehicle body depending on the situation. That's not even a good thing.

By the way, in the above-mentioned embodiment, a case was shown in which the high speed range and low speed range are automatically determined based on the value of the speed sensor 26, but the present invention is not limited to this, and all drivers in the high speed range and low speed range It is also possible to set it so that it is switched manually. In this case, the driver is in control. If you want to emphasize quality, select a high speed range and set the aperture amount of the barrier pull orifice 24 with emphasis on the X direction on the custom line C in Fig. 5, while if you want to emphasize ride comfort, select a high speed range. The aperture amount of the barrier pull orifice 24 is set with emphasis on the Y direction on the characteristic line C.

Furthermore, in the above embodiment, the lateral G generated when the vehicle turns
Although we have disclosed a system in which the spring constant of the anti-vibration rubber ■2 is completely changed in consideration of =i, the present invention is not limited to this;
All rear G (acceleration) is detected and input to the controller 23,
Is there a spring on the anti-vibration rubber 12 even during sudden braking? z'
It is also possible to prevent the suspension arm 3 from swinging from side to side by making Mk large.

As described in detail, the vehicle suspension system of the present invention includes:
The first part formed on the anti-vibration rubber. Since the movement of the working fluid between the second rod chambers is adjusted steplessly by the barrier pull orifice, precise control is possible, completely preventing the spring constant of the vibration isolating rubber from becoming unnecessarily large when the vehicle turns. It has an excellent ability to absorb road vibrations, thereby reducing the humming noise inside the single room, and also improving ride comfort compared to conventional ones.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a heavy duty suspension system showing one embodiment of the present invention, Fig. 2 is an enlarged sectional view taken from the line ■-■ in Fig. 1, and Fig.
The figure is an enlarged cross-sectional view of part 9 taken from line ■-I in Figure 1, Figure 4 is an explanation showing the operating state of the suspension arm, and Figure 5 is an enlarged sectional view of the suspension arm used in the vehicle suspension system of the present invention. % gender chart. DESCRIPTION OF SYMBOLS 1... Vehicle suspension f<s3... Suspension arm, 4, 4a... Bush, 5... The suspension member, 12... Vibration isolating rubber, 13... Bolt (
Mounting Gl + ), 2゜゛°° 1st θb, body chamber, 21・
...Second fluid chamber, 22...Communication path, 24...Barrier pull orifice. 2 people Figure 2 Figure 3

Claims (1)

[Claims] (1) First and second fluid chambers filled with working fluid are formed in the anti-vibration rubber of the bushing that connects the suspension arm to the vehicle body on the front and rear sides of the vehicle with respect to the mounting shaft of the bushing, and A vehicle suspension system k characterized in that these first and second fluid chambers are communicated through a communication path, and a barrier pull orifice is provided in the communication path, the orifice diameter of which is variably controlled depending on the running condition. .