JP2621603B2 - Center bearing insulator - Google Patents

Description

The present invention relates to a center bearing insulator applied to a propeller shaft having three or more joints as a vehicle body support member.

(Prior art) Conventionally, as a center bearing insulator,
For example, those shown in FIG. 5 and those shown in FIG. 6 are known.

The center bearing insulator shown in FIG. 5 has only a hollow cylindrical insulator, and is made of a rubber material capable of securing a certain spring constant even at a high temperature for the following reason.

In other words, if idle at high temperature and after high-load operation, the temperature of the center bearing insulator rises excessively, the spring constant of the insulator decreases, and the displacement of the propeller shaft increases when the vehicle starts running next time. The propeller shaft is struck against the vehicle body, producing a striking sound.

Therefore, the center bearing insulator shown in FIG. 6 is designed to prevent the propeller shaft from being hit against the vehicle body, and a stopper rubber is incorporated in a hollow cylindrical insulator.

(Problems to be Solved by the Invention) However, the conventional sunter bearing insulator shown in FIG. 5 is an insulator using a rubber material capable of securing a certain spring constant even at a high temperature.
Although hitting noise can be prevented, the spring constant is too high at normal temperature (during normal running), and the effect of blocking vibration transmitted from the propeller shaft via the center bearing insulator is low.

Note that the spring constant is usually proportional to the temperature, and the lower the temperature, the higher the spring constant.

On the other hand, in the conventional center bearing insulator shown in FIG. 6, when a rubber material of the insulator having a low spring constant at normal temperature is used, the vibration proof performance can be ensured and the hitting noise can be reduced by the stopper rubber.

However, the stopper rubber hits the vehicle body when a displacement exceeding the clearance between the stopper rubber and the vehicle body occurs on the propeller shaft.If this clearance is set small, the stopper rubber will hit the vehicle body even during normal running When the clearance is set to be large, the stopper rubber hits the vehicle body with a large shaft displacement, so that a large tapping sound is generated. That is,
It is very difficult to control the dimensions of the clearance between the stopper rubber and the vehicle body.

The present invention has been made in view of the above-described problems.In a center bearing insulator having a bearing and an insulator, high vibration isolation performance at room temperature and high temperature at high temperature without requiring strict dimensional control. It is an object of the present invention to achieve both the prevention of the occurrence of a tapping sound at the same time.

(Means for Solving the Problems) In order to solve the above problems, in the center bearing insulator of the present invention, a bearing inserted into the outer periphery of a propeller shaft and an insulator arranged between the bearing and the vehicle body are provided. In the center bearing insulator provided, the insulator is formed in a hollow cylindrical shape from a rubber material having a low spring constant that exhibits a high vibration isolation effect at room temperature, and the insulator has a high-temperature region exceeding a set temperature at which a hitting sound evaluation is reduced. A built-in auxiliary insulator filled with a liquid that evaporates at the time. At room temperature, the auxiliary insulator maintains sufficient clearance between the bearing and the vehicle body due to liquefaction contraction of the sealed liquid. Expands and contracts so as to be interposed between the bearing and the vehicle body due to the vaporization and expansion of the liquid It is characterized by being formed of a material having high properties.

(Operation) At room temperature (normal running), the liquid filled in the auxiliary insulator is in a liquefied and contracted state, and the auxiliary insulator does not act on vibration isolation.

Therefore, vibration that is transmitted from the propeller shaft to the vehicle body during traveling will be performed by the insulator alone, but since it is not necessary to consider the tapping sound at high temperatures, the insulator has a relatively low spring constant. A low rubber material can be used, and effective vibration isolation can be achieved.

If you leave it idle after high load operation under high temperature,
The temperature of the center bearing insulator rises.
At this high temperature, the temperature of the auxiliary insulator raises the temperature of the sealed liquid and the volume thereof expands, and the spring constant is increased by the two insulators arranged in parallel with each other.

Therefore, the displacement of the propeller shaft at the time of starting next run is suppressed to a small value, and the hitting sound is prevented.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

 First, the configuration will be described.

FIG. 1 is a sectional view of a center bearing insulator according to an embodiment of the present invention, and FIG. 2 is a diagram showing a three joint type propeller shaft unit to which the center bearing insulator of the embodiment is applied.

As shown in FIG. 2, the three-joint type propeller shaft unit includes a first propeller shaft 1 arranged on the transmission side, a second propeller shaft 2 arranged on the differential side, and a connection between the two propeller shafts 1 and 2. And three universal joints 3, 4, and 5 provided at both ends.

The center bearing insulator A of the embodiment is applied as a vehicle body support member at a position near the universal joint 4 of the first propeller shaft 1.

As shown in FIG. 1, the center bearing insulator A includes a ball bearing 6 inserted into the outer periphery of the first propeller shaft 1, an insulator 8 disposed between the ball bearing 6 and the vehicle body 7, The insulator 8 includes an auxiliary insulator 10 which is built in a parallel relationship on the propeller shaft side and in which a sealed liquid 9 (for example, ethyl alcohol, benzene, or the like) which is vaporized in a high temperature region exceeding a set temperature of about 80 ° is filled. Have been.

The insulator 8 is formed in a hollow cylindrical shape from a rubber material having a low spring constant and exhibiting a high vibration isolation effect at normal temperature, and a bearing-side bracket 11 is provided on an inner periphery thereof, and a vehicle-side bracket 12 is provided on an outer periphery thereof. Is provided.

The auxiliary insulator 10 is formed of a highly elastic butyl rubber (IIR) used as a tire tube, and a rubber plate is provided on a surface facing the vehicle body 7.
13 are provided.

 Next, the operation will be described.

(A) At normal temperature At normal temperature (normal running), as shown in FIG. 1, the filling liquid 9 of the auxiliary insulator 10 is in a liquefied and contracted state, and the auxiliary insulator 10 does not act on vibration isolation.

Therefore, during the traveling, the vibration transmitted from the first propeller shaft 1 to the vehicle body 7 is prevented by the insulator 8 alone. However, since it is not necessary to consider the tapping sound at high temperature, since the insulator 8 is made of a rubber material having a relatively low spring constant, effective vibration isolation is performed.

(B) High temperature If the engine is left idle after high load operation at high temperature,
The heat of the power plant passes through the universal joint 3 and the first propeller shaft 1 and the center bearing insulator A
And the temperature of the center bearing insulator A rises.

At this high temperature, the temperature of the insulator 8 and the auxiliary insulator 10 rises, and as shown in FIG. 3, the filled liquid 9 of the auxiliary insulator 10 evaporates and its volume expands.
Insulator 8 between ball bearing 6 and vehicle body 7
And the auxiliary insulator 10 are provided in a parallel relationship with each other, and the spring constant is increased by the two insulators 8 and 10.

Accordingly, the displacement of the first propeller shaft 1 when starting next time is suppressed to a small value, and the generation of a tapping sound due to the first propeller shaft 1 being hit against the vehicle body 7 is prevented.

Incidentally, the reason why the vaporization temperature of the filling liquid 9 in the auxiliary insulator 10 was set to about 80 ° C. is that the tapping sound evaluation with respect to the temperature was conducted by an experiment using the center bearing insulator shown in FIG. As described above, up to 80 評, the hitting score was 5 and almost no hitting sound was generated, but the hitting score dropped suddenly from the point of exceeding 80 ゜, and the hitting sound generation became remarkable. It depends.

As described above, the center bearing insulator A of the embodiment has the following effects.

Auxiliary insulators 10 filled with a liquid that evaporates in a high temperature range above the set temperature of about 80 ° C are built into the insulators 8 in a parallel relationship, so that strict dimensional control such as when a stopper rubber is provided is not required. It is possible to achieve both high vibration isolation performance and prevention of hammering sound at high temperatures.

Since the auxiliary insulator 10 is built in the insulator 8, the appearance of the auxiliary insulator 10 can be completely the same as that of the conventional one without taking a space for providing the auxiliary insulator 10 in another place. As a result, it is possible to prevent the auxiliary insulator 10 from being damaged by the collision of pebbles or the like and the leakage of the filled liquid during traveling.

Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration is not limited to this embodiment.

For example, in the embodiment, an example is shown in which the auxiliary insulator is built in the propeller shaft side of the insulator.
The auxiliary insulator may be built in the insulator on the vehicle body side.

(Effect of the Invention) As described above, according to the present invention, in the center bearing insulator including the bearing and the insulator, the insulator is made of a rubber material having a low spring constant and exhibiting a high vibration isolation effect at normal temperature. Built in a hollow cylindrical shape, the insulator incorporates an auxiliary insulator filled with a liquid that evaporates in a high temperature range exceeding the set temperature at which the hitting sound evaluation is reduced.The auxiliary insulator is a bearing at room temperature due to liquefaction shrinkage of the sealed liquid. Or, maintain a sufficient clearance between the body and the high temperature exceeding the set temperature, because it is formed of a highly elastic material so that it is interposed between the bearing and the body by vaporization and expansion of the sealed liquid, The effect is obtained.

(1) It is possible to achieve both high vibration isolation performance at normal temperature and prevention of hitting noise at high temperatures without requiring strict dimensional control as in the case of providing a stopper rubber.

(2) Since the auxiliary insulator is built into the insulator, the external insulator can be made exactly the same as the conventional one without taking the space for installing the auxiliary insulator in another place, and the auxiliary insulator is protected by the insulator. By doing so, it is possible to prevent the auxiliary insulator from being damaged due to collision of pebbles or the like during traveling and leakage of the sealed liquid.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a center bearing insulator according to an embodiment of the present invention, FIG. 2 is a view showing a three-joint type propeller shaft unit to which the center bearing insulator of the present invention is applied, and FIG. FIG. 4 is a sectional view showing the state, FIG. 4 is a characteristic diagram showing the relationship between the temperature of the center bearing insulator and the hitting score, and FIGS. 5 and 6 are sectional views showing a conventional center bearing insulator. A: Sensor bearing insulator 1: First propeller shaft (propeller shaft) 6: Ball bearing (bearing) 7: Body 8: Insulator 9: Filled liquid 10: Auxiliary insulator

Claims (1)

(57) [Claims] 1. A center bearing insulator comprising a bearing inserted around an outer periphery of a propeller shaft and an insulator arranged between the bearing and a vehicle body, wherein the insulator exhibits a high vibration-proof effect at room temperature. The auxiliary insulator is formed in a hollow cylindrical shape with a rubber material having a low spring constant, and the insulator incorporates an auxiliary insulator filled with a liquid that evaporates in a high temperature region exceeding a set temperature at which the hitting sound evaluation is reduced. At the time, sufficient clearance is maintained between the bearing and the vehicle body due to liquefied contraction of the filled liquid, and at high temperatures exceeding the set temperature, it expands and contracts so as to be interposed between the bearing and the vehicle body due to vaporization and expansion of the filled liquid A center bearing insulator made of highly conductive material.