JPH03117740A - Bush mechanism - Google Patents

Abstract

PURPOSE:To eliminate low- and high-frequency oscillations by providing liquid chambers communicated with each other through orifices in a rubber fitted between inner and outer cylinders of a bush used for a trailing link of a vehicle, and also providing air chambers. CONSTITUTION:A front end 3a of a trailing link 3 of a vehicle is connected to a body 5 by means of a bush 4. Liquid chambers 9a and 9b, which are arranged in a rubber 8 fitted in a space between inner and outer cylinders 6, 7 of the bush 4, opposingly to each other across the inner cylinder 6, are communicated with each other through orifices 10, 10. Air chambers 11a, 11b are arranged outside the liquid chambers 9a, 9b in the rubber 8, opposingly to each other across the inner cylinder 6. When oscillations of low-frequency area are applied to a wheel 1 during turning, oil in the liquid chambers 9a, 9b flows reciprocally through the orifices 10. The fluid resistance caused thereby attenuates the low-frequency oscillations. High-frequency oscillations to be generated, for instance, when the wheel 1 runs on a pebble are not attenuated through the orifices 10 because of their locked condition, however, attenuated by means of the air chambers 11a, 1b because of their deformation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a bushing structure, and more particularly to a bushing structure in which a liquid chamber and an air chamber are provided in rubber to provide vibration isolation.

(Prior art) For example, in Japanese Patent Application Laid-Open No. 58-170609, liquid chambers are provided in a rubber fitted between an inner cylinder and an outer cylinder, and which face each other with the inner cylinder in between. A bushing is disclosed in which fluid chambers are communicated through an orifice and oil is sealed within the fluid chambers.

(Problem to be Solved by the Invention) When the above bushing is used in the trailing link of a vehicle, vibrations transmitted from the wheels to the trailing link are These are vibrations in a low frequency range where the number of vibrations per unit time is relatively small. In such a case, the oil in both liquid chambers flows back and forth within the orifice due to vibrations transmitted from the wheels, and the fluid resistance at that time dampens low-frequency vibrations, resulting in improved maneuverability.

However, when driving on a road surface with scattered pebbles, the vibrations transmitted from the wheels to the trailing link are vibrations in a high frequency range with a relatively high frequency per unit time. In the case of such high-frequency vibrations, the oil cannot flow back and forth within the orifice as described above, which means that the orifice becomes locked and the roughness of the wheels is transmitted directly to the vehicle body via the trailing link, which affects ride comfort. The problem is that it makes things worse. In other words, the above-mentioned bush cannot block both low-frequency vibrations and high-frequency vibrations with the same push.

The present invention has been made in view of the above points.
The purpose is to provide a bushing structure that can effectively weaken the vibration force not only in the low frequency range of vibration but also in the high frequency range.

(Means for solving the problems) As shown in FIGS. 1 and 2 of the embodiment drawings, the present invention provides an inner cylinder 6
In a bushing structure comprising an outer cylinder 7 and a rubber 8 fitted between the cylinders 6 and 7, the rubber 8 is provided with a plurality of liquid chambers 9a and 9b facing each other with the inner cylinder 6 in between, The plurality of liquid chambers are communicated with each other through an orifice 10, and a plurality of air chambers 11a and llb are provided which face each other with the inner cylinder 6 in between.

(Operation) When low frequency vibrations act on the rubber 8 between the two cylinders 6 and 7, oil flows back and forth in the orifice 10 between the liquid chambers, and the low frequency vibrations are attenuated by the fluid resistance. Also,
When high frequency vibration acts on the rubber 8, the orifice 1
0 is locked and no damping effect is obtained, but multiple air chambers 1
The highly compressible gas such as air in 1a and llb can absorb high frequency vibrations and exert a damping effect.

(Example) An embodiment of the present invention will be described based on the drawings.

FIG. 1 is a side view showing the case where the present invention is implemented in a strut type rear suspension. 1 is a car wheel, 2
The coil spring and shock absorber 23 is a trailing link, and is connected to the vehicle body 5 via a bush 4 at the front end 3a and to the axle at the rear end 3b.

FIG. 2 is an explanatory diagram showing a cross section of the bushing 4. FIG. 6 is an inner cylinder, 7 is an outer cylinder, and 8 is a rubber fitted in the space between the cylinders 6 and 7. A plurality of liquid chambers 9a and 9b are provided inside the rubber 8 and are opposed to each other with the inner cylinder 6 in between.
They are communicated through an orifice 10.10. Further, inside the rubber 8, a plurality of air chambers 11a and llb are provided outside the liquid chambers 9a and 9b, respectively, facing each other with the inner cylinder 6 in between.

Further, the inner cylinder 6 is connected to the vehicle body 5 side, and the outer cylinder 7 is connected to the trailing link 3.

Therefore, when the wheel 1 vibrates up and down in small increments while the car is running on pebbles on the road surface, that is, when it receives vibration in the high frequency range, the vibration is transmitted to the front end 3a of the trailing link 3.
It is further transmitted from the outer cylinder 7 of the bushing 4 to the rubber 8. As a result, the rubber 8 vibrates due to the vibration force with a high frequency, and the oil in the liquid chambers 9a and 9b similarly vibrates, but the orifice 10.10 that communicates the two is incompressible due to the high frequency. The oil cannot flow through the orifice 10.
10 is in a locked state, and vibrations in the high frequency range are not weakened by the oil.

On the other hand, the air in the air chambers 11a and llb is also subjected to high-frequency vibrations similar to oil, but since air is compressible, the air chambers 11a and llb can deform, and the vibration force is absorbed and weakened. As a result, small-step vibrations of the wheels 1 are not transmitted to the vehicle body 5 side, so that there is no rough feeling and the riding comfort is not deteriorated.

Furthermore, when the wheels are subjected to vibrations in the low frequency range, such as when the car is turning, the oil in both liquid chambers 9a and 9b flows back and forth through the orifices 10 and 10, as explained in the prior art section. The fluid resistance consumes energy and damps low-frequency vibrations.

In addition to the embodiments described above, the bushing of the present invention can be used for engine mounts. In this case, by fixing the outer cylinder to the engine body and attaching the inner cylinder to the vehicle body, transmission of high-frequency vibrations and low-frequency vibrations generated by the engine to the vehicle body can be largely blocked.

(5 Effects of the Invention) The present invention provides a plurality of liquid chambers communicating with each other through an orifice in the rubber fitted between the inner and outer cylinders, as well as a plurality of air chambers. can be effectively damped, and the latter can absorb high frequency vibrations.

Therefore, according to the present invention, it is possible to block vibrations in the high and heavy rain frequency range with the same push. For example, when the above-mentioned bushings are used in a car's suspension system, vibrations in the low frequency range generated by the wheels when turning are attenuated by the action of the fluid chamber communicated with the orifice, ensuring maneuverability, and The high-frequency vibrations generated by the wheels when driving on rough roads are absorbed by the air chambers, eliminating the rough feeling.

[Brief explanation of drawings]

FIG. 1 is a side view of a suspension device for a vehicle using the bushing of the present invention, and FIG. 2 is an explanatory view showing a cross section of the bushing. 6.Inner cylinder 7.Outer cylinder 8.Rubber 9a, 9b.Liquid chamber

Claims (1)

[Claims] In a bush structure including an inner cylinder, an outer cylinder, and a rubber fitted between the two cylinders, a plurality of liquid chambers are provided in the rubber and face each other with the inner cylinder interposed therebetween, and an orifice is provided between the plurality of liquid chambers. A bush structure characterized in that a plurality of air chambers are provided that communicate with each other and face each other with the inner cylinder in between.