JPH04224421A - Supporting device for propeller shaft of car - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a support device for a propeller shaft for a vehicle, and is particularly suitable when the propeller shaft consists of a plurality of shafts and a universal joint that interconnects adjacent shafts. Relating to a support device.

0002

[Prior Art] When a propeller shaft is composed of a plurality of shafts and a universal joint that interconnects adjacent shafts, the propeller shaft is supported by a support device including a rolling bearing. The joint angle formed by the shaft located at the front and the shaft located at the rear across the vehicle changes depending on the driving torque when the vehicle starts, creating a secondary couple. Due to this secondary couple, 10~
A vibration of 15Hz is generated. On the other hand, when the vehicle is running, due to unbalanced rotation of the propeller shaft, the
0Hz vibration occurs.

[0003] In order to reduce the two types of vibrations having different frequencies, a supporting device (Utility Model Application Laid-Open No. 2003-119012) is designed to change the flow resistance of the liquid contained in a hollow cushion between when the vehicle starts and when the vehicle is running. 18723) and other support devices have been proposed.

0004

[Problem to be solved by the invention] Both support devices
In addition to making the structure more complicated or larger, it also has two different frequencies.
The effect of reducing various kinds of vibrations is not necessarily sufficient.

By the way, in order to suppress the occurrence of vibrations caused by the secondary couple when starting, it is sufficient to increase the spring constant of the cushion and reduce changes in the joint angle. To suppress this, the spring constant of the cushion can be lowered. The spring constant when starting is a static spring constant, and the spring constant when running is a dynamic spring constant.The dynamic magnification, which is the ratio of the cushion's dynamic spring constant to the static spring constant, is the same as when the cushion is made of ordinary rubber. , the value is high and the above requirement cannot be met.

SUMMARY OF THE INVENTION An object of the present invention is to provide a support device for a propeller shaft for a vehicle that can improve the effect of reducing vibrations generated during starting and vibrations generated during running without making the structure complicated or large. There is a particular thing.

[0007]

[Means for Solving the Problems] A supporting device for a propeller shaft for a vehicle according to the present invention includes a rolling bearing that rotatably supports a propeller shaft, and a short fiber reinforcement disposed radially outward of the rolling bearing. The vehicle includes an annular cushion made of rubber and a support member disposed radially outward of the cushion and attached to the vehicle body.

[0008]

[Function and Effect] The inventors have confirmed that the cushion made of short fiber reinforced rubber has a low dynamic magnification. According to this fact, even if the static spring constant of the cushion is set to a large value, the dynamic spring constant will be maintained at a small value. As a result, it is possible to reduce vibrations caused by changes in the joint angle due to the secondary couple when the vehicle starts, and it is also possible to reduce vibrations caused by unbalanced rotation of the propeller shaft during running.

[0009] The support device consists of a rolling bearing, a cushion, and a support member, and since it is not necessary to provide a fluid chamber or the like in the cushion, the overall structure is simple and can be downsized.

0010

[Example] A support device for a vehicle propeller shaft is shown in Figure 1.
And as shown in FIG. 2, it includes a rolling bearing 10, a cushion 12, and a support member 14.

In the illustrated embodiment, the rolling bearing 10 includes:
It includes an inner ring 16, an outer ring 18, a plurality of balls 20 arranged between the two rings, and a case 22. A propeller shaft 24 is fixed to the inner ring 16 and rotatably supported by balls 20. The outer ring 18 is fitted into the case 22.

The cushion 12 is formed into an annular shape, is arranged radially outward of the rolling bearing 10, and is made of short fiber reinforced rubber. The short fibers 26 are, for example, nylon 6 with an average diameter of 0.3 μm or less and a length of 1 to several μm, and the rubber is natural rubber with a hardness of 30 to 50 Hs.

In the embodiment shown in FIGS. 1 and 2, the cushion 12 is formed by arranging short fibers 26 in the radial direction. This arrangement of the short fibers 26 makes the cushion 12
is hard in the radial direction and soft in the axial direction. Since the spring constant of the cushion 12 tends to increase as it becomes harder, the spring constant in the radial direction is larger than the spring constant in the axial direction. In this example, the amount of short fibers may be 5-10% by weight of the rubber.

In the embodiment shown in FIGS. 3 and 4, the short fibers 26 are arranged in the axial direction, and in the embodiment shown in FIGS. 5 and 6, the short fibers 26 are arranged in the circumferential direction. In the case of these examples, the amount of short fibers is 10 to 20% of that of rubber.
Weight%.

[0015] When short fibers are mixed with rubber and sufficiently dispersed and then extrusion molded or injection molded, the rubber flows in one direction, but the short fibers tend to align in the direction of flow of the rubber. By utilizing this property, short fibers can be given directionality.

After the cushion 12 is formed into an annular shape by giving the short fibers 26 a desired directionality, the cushion 12 is bonded to the case 22 on its inner circumferential surface and to the support member 14 on its outer circumferential surface.

The support member 14 has a cylindrical shape, is disposed radially outward of the cushion 12, and is attached to the vehicle body (not shown).
can be attached to.

The magnitude of the load per unit amplitude when the frequency is near zero is called a static spring constant, whereas the magnitude of the load per unit amplitude at a certain frequency is called a dynamic spring constant. The dynamic spring constants both depend on the frequency, as shown in the rubber cushion model shown in Figure 7.
If Kd is the storage spring constant, C is the damping coefficient, and f is the frequency, it is equal to the absolute spring constant given by the following equation. These relationships are described on pages 55 and below of "Vibration Isolation Rubber" (published by Japan Railway Vehicle Manufacturers Association).

[0019]

[Math 1]

In the case of a conventional cushion formed only from rubber, its static spring constant was 6.40 kgf/mm, but as shown in FIGS. The static spring constant of the reinforced rubber cushion 12 was 11.57 kgf/mm. Cushion 12
The frequency characteristic of the absolute spring constant was the solid line in FIG. 8, and the dynamic magnification at that time was the broken line. On the other hand, the frequency characteristic of the absolute spring constant of the conventional cushion made only of rubber was the solid line in FIG. 9, and the dynamic magnification at that time was the broken line.

In the short fiber reinforced rubber cushion shown in FIG.
Although the dynamic magnification is 2 at most, the dynamic magnification is 4.6 in the cushion made only of rubber shown in FIG. Therefore, in the cushion made of short fiber reinforced rubber, the absolute spring constant or dynamic spring constant is 23.14 kgf/mm.
With a cushion made only of rubber, 29.44 kgf/mm
becomes. In other words, in the case of the present invention, although the static spring constant of the cushion is large, the dynamic spring constant is small, and the vibration caused by the secondary couple at the time of starting is also reduced due to the rotational imbalance of the propeller shaft during running. It can be seen that vibrations caused by balance can also be reduced.

[0022] In the above embodiment, the cushion 1
2 is located eccentrically with respect to the rolling bearing 10. This provides the following effects. That is, when the support device is assembled to the vehicle, the inner ring 1 of the rolling bearing 10
The weight of the propeller shaft is applied to cushion 12
The center of the cushion 12 and the center of the inner ring 16 can be made to coincide with each other. As a result, the arrangement direction of the short fibers in the cushion 12 can be made symmetrical.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a vehicle propeller shaft support device according to the present invention.

FIG. 2 is a right side view of the support device, showing the left half.

FIG. 3 is a sectional view of another embodiment of the support device;

FIG. 4 is a right side view of another embodiment of the support device, showing the left half;

FIG. 5 is a sectional view of a further embodiment of a support device;

FIG. 6 is a right side view of a further embodiment of the support device, showing the left half;

FIG. 7 is a vibration model diagram of a rubber cushion.

FIG. 8 is a frequency characteristic diagram of the absolute spring constant of a cushion made of short fiber reinforced rubber.

FIG. 9 is a frequency characteristic diagram of the absolute spring constant of a cushion made only of rubber.

[Explanation of symbols]

10 Rolling bearing 12 Cushion 14 Support member 26 Short fiber

Claims (1)

[Claims] Claim 1: A rolling bearing rotatably supporting a propeller shaft; an annular cushion made of short fiber reinforced rubber disposed radially outward of the rolling bearing; A support device for a propeller shaft for a vehicle, comprising a support member arranged and attached to a vehicle body.