JPS6015007Y2 - Cylindrical bushing assembly - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a cylindrical bush assembly suitable for being incorporated into a pivot joint in a vehicle or the like for vibration isolation.

(Prior Art) Some conventional cylindrical bushing assemblies of this type are incorporated, for example, in a pivot connection between a suspension member and a vehicle body in a trailing arm type suspension system.

This bushing assembly, as shown in FIG.
A pair of dividing grooves 1 having a substantially T-shaped cross section for setting a spring constant in a direction perpendicular to the X-X direction to be smaller than a spring constant in a predetermined radial direction (X-X direction).
0 is formed, an inner cylinder 1.4 that covers the inner peripheral surface of the elastic member, and a divided outer cylinder that includes a pair of arc-shaped members 16 that covers the outer peripheral surface of the elastic member 12. .

The bushing assembly is press-fitted into the bushing mounting hole 18 with its elastic member 12 being compressed between both plate-shaped members 18, and the bushing assembly is pushed by the elastic repulsive force of the elastic member 12 in the X-X direction. It is held in the bush mounting hole 18.

In order to improve the vibration damping properties of the bushing assembly, it is desirable to use a so-called soft elastic member as the elastic member 12.

However, the bushing assembly has its elastic member 12
Since the bushing is held in the mounting hole 18 by the elastic repulsive force of the outer cylinder 16.1, if a soft elastic member is used as the elastic member 12, the elastic repulsive force decreases and
6 may come out from the bush mounting hole.

Therefore, it has been proposed to fix an elastic material to the opposing dividing surfaces of the divided outer cylinder, which is compressed between the dividing surfaces when attached to the bushing mounting hole (publication of Utility Model Publication No. 54-24234).
.

According to this, when the bushing is attached to the mounting tube as the bushing mounting hole, the elastic material fixed to the opposing dividing surfaces 16 and 16 of the outer tube, that is, the mutually opposing surfaces of the outer tube, is inserted between the dividing surfaces. The elastic repulsive force caused by this compression increases the frictional force between the divided outer cylinder and the bush mounting hole, so even if a soft elastic member is used as the elastic member, the elastic material will not exert a predetermined repulsive force. As long as the bushing assembly is used, the bushing assembly can be prevented from falling off from the mounting tube.

(Problem that the invention attempts to solve) However, the split outer cylinder is generally made of rigid material,
When attached to the mounting tube, the elastic material is directly compressed between the divided surfaces of the divided outer tube made of this rigid material, and the divided surfaces themselves do not undergo elastic deformation.

Therefore, the accuracy of the dimension between the dividing surfaces and the thickness of the elastic material in the dimension direction has a large influence on the elastic repulsion force.

Therefore, in order to obtain a predetermined elastic repulsive force using the elastic material, high dimensional accuracy is required for the outer cylinder and the elastic material, leading to a rise in manufacturing costs.

Moreover, since the elastic body disposed between the divided surfaces of the outer cylinder receives compressive force only at the divided surfaces of the divided outer cylinder having a small plate thickness when attached to the mounting tube, the elastic body is Because the area is extremely small and elastic fatigue is severe,
Since the elastic material lacks durability and cannot exert a predetermined elastic repulsion force over a long period of time, there is a risk that the bushing assembly may unexpectedly fall off from the mounting tube after long-term use.

Furthermore, since the elastic material is subjected to compressive force only at the dividing surface of the divided outer cylinder having a small plate thickness when it is installed in the bushing mounting hole, the The elastic material tends to buckle inward at the split surfaces of the split outer cylinder, and therefore, in order to obtain a predetermined elastic repulsive force, the elastic material is moved between the split surfaces in a predetermined form that does not cause buckling. It is not easy to assemble the bushing assembly to the mounting tube so that it can be compressed, and therefore, there is a drawback that the assembly of the bushing assembly is time-consuming.

Therefore, the purpose of this invention is to provide excellent vibration isolation and durability.
To provide a cylindrical bushing assembly that does not come off from a predetermined location over a long period of time and is easy to assemble.

(Means for solving the problem) The present invention is a cylindrical bushing assembly that is press-fitted into a bushing mounting hole, and has an oval cross section as a whole, and a pair of bushings formed symmetrically with respect to its major axis. A pair of dividing grooves each consisting of a first groove portion extending substantially along the major axis direction and a second groove portion extending from the groove portion along the minor axis direction and opening to the outer peripheral surface. A cylindrical elastic member provided, an inner cylinder disposed to cover the inner peripheral surface of the elastic member, and an inner cylinder disposed to cover the outer peripheral surface of the elastic member to prevent compressive deformation in the longitudinal direction of the elastic member. In a cylindrical bushing assembly including a divided outer cylinder, the length of the elastic member as an elastic member for imparting elasticity to the divided outer cylinder is equal to the thickness of the divided outer cylinder. larger than the dimensions of the bushing assembly, and which receives a compressive force between the opposing groove surfaces of the second groove portion when the bushing assembly is press-fitted into the bushing mounting hole, and which is capable of penetrating between the opposing surfaces of the split outer cylinder. The present invention is characterized in that a block-shaped elastic body is disposed within the front second groove portion.

(Operations and Effects) According to the present invention, the elastic body that provides an elastic repulsion force to the divided outer cylinder when attached to the bushing attachment hole is a member of the second elastic body formed on the elastic member that is elastically deformable. It is compressed between the full surfaces of the groove portion and does not enter between the divided surfaces of the divided outer cylinder.

Therefore, the elastic body is not compressed between the divided surfaces of the divided outer cylinder, that is, the opposing surfaces of the divided outer cylinder, and therefore does not enter between the divided surfaces of the divided outer cylinder.

Therefore, the elastic body is not compressed between the divided surfaces of the divided outer cylinder, that is, between the opposing surfaces of the divided outer cylinder, so that the dimensional accuracy between the divided surfaces of the divided outer cylinder is reduced by the elastic body. This does not affect the repulsive force, and there is no need to use a conventional divided outer cylinder that has been processed with high precision as the divided outer cylinder.

Furthermore, since both the elastic body and the elastic member receiving the elastic body are elastically deformable, the dimension between the groove surfaces of the second groove portion in which the elastic body is disposed, and the The accuracy of the thickness dimension of the elastic body does not have a large effect on the elastic repulsive force by the elastic body as in the conventional case.

Therefore, it is possible to obtain a predetermined elastic repulsion force by the elastic body without requiring high dimensional accuracy for any of the outer cylinder, the elastic member, and the elastic body as in the conventional case. It is possible to obtain a bushing assembly which is excellent in performance and does not fall off from a predetermined location at a lower cost than conventional bushings.

Further, the elastic body disposed between the dividing surfaces of the outer cylinder is
Since the elastic member is a block-shaped elastic body whose length along the minor axis direction is larger than the plate thickness of the outer cylinder, the elastic member receives compressive force when installed in the bush mounting hole. The elastic body has a large pressure-receiving cross-sectional area, so that elastic fatigue is unlikely to occur in the elastic body, and the elastic body exerts a predetermined elastic repulsion force even after long-term use.

Therefore, even after long-term use, the elastic repulsive force of the elastic body can reliably prevent the bushing assembly from accidentally falling off from the bushing mounting hole.

Furthermore, since the elastic body is a block-shaped elastic body whose length along the minor axis direction of the elastic member is larger than the plate thickness of the outer cylinder, the bush of the bush assembly When attached to the attachment hole, the elastic body does not buckle between the groove surfaces of the second groove portion, making it possible to assemble the bushing assembly quickly and easily.

Moreover, the elastic body which is in a compressed state within the second groove portion is subjected to a strong external force in the short diameter direction of the elastic member that completely compresses the first groove portion in the width direction of the outer cylinder. When acting between the outer cylinder and the inner cylinder, the inner cylinder undergoes elastic deformation due to the external force, thereby acting as a buffer against the external force.

Therefore, in response to an external force acting between the outer cylinder and the inner cylinder that completely compresses the first groove portion in the width direction, the elastic body substantially reduces the effective pressure-receiving cross-sectional area of the elastic member. This increases the durability of the elastic member against strong external forces such as those described above, thereby increasing the durability of the bushing assembly.

(Example) The features of the present invention will become clearer from the following description of the illustrated embodiment.

As shown in FIGS. 2 and 3, the bushing assembly 20 according to the present invention includes a cylindrical elastic member 22, which is inserted into the inner hole of the elastic member and fixed to the circumferential surface thereof. The elastic member 22 includes a cylinder, that is, an inner tube 24, and a divided outer tube consisting of a pair of arcuate members 26 having a semicircular cross section and fixed to the outer circumferential surface of the elastic member 22 so as to cover the outer circumferential surface.

The elastic member 22, as clearly shown in FIG.
It has an oval cross section throughout.

A pair of dividing grooves 28 are formed in the elastic member 22 and are symmetrical with respect to the major axis thereof.

Each dividing groove 28 is formed in the longitudinal direction of the elastic member 22, that is, in the X-
A first groove portion 30 extending along the X direction and having both shorter lengths attributable to circular portions, and a first groove portion 30 extending outward in the shorter diameter direction, that is, in the radial direction perpendicular to the X-X direction from the center of the first groove portion. It consists of a second groove portion 32.

Each dividing groove 28 extends from one end of the elastic member 22 to the other end, and opens along the axial direction of the outer circumferential surface of the elastic member 22 at a second groove portion 32 corresponding to between both arcuate members 26. .

Within the second groove portion 32 are groove surfaces 32 facing each other.
An elastic body 34 is arranged to abut both sides of a.

The length dimension of the elastic member in the elastic body 34 along the minor axis direction is larger than the plate thickness dimension of the divided outer cylinder, and the elastic body 34 also compresses the divided outer cylinder 26 by compression between the groove surfaces 32a to be described later. It is a block-shaped elastic body of a size that does not penetrate between the facing surfaces of the divided outer cylinder 26, that is, the divided surfaces of the divided outer cylinder 26.

As this elastic body 34, for example, rubber having a hardness of 40 to 90 can be used, and as shown in FIG.
is held between both groove surfaces 32a.

Both sides of the elastic body 34 can be fixed to each groove surface 32a, or the elastic body 34 can be molded integrally with the elastic member 22.

The width dimension of the elastic body 34, that is, the dimension along the longer diameter direction of the elastic member 22 in the elastic body is the groove surface 32a in the state of being press-fitted into the bush attachment hole of the bush assembly.

As long as it is within a range larger than the spacing between the groove surfaces 32a and 32a, it can be made smaller than the spacing between the groove surfaces 32a and 32a in the uncompressed state shown in FIG. It is fixed to the surface 32a.

Further, the elastic body can be constituted by a protrusion integrally formed on the elastic member 22 so as to protrude from one groove surface 32a toward the other groove surface 32a and to be spaced apart from the groove surface.

FIG. 4 shows an example of the use of the bushing assembly 20.
The bushing assembly is attached to the vehicle body 3 of the suspension member 36.
An example is shown for use in a pivot connection to 8.

A mounting cylinder 40 that defines a bushing mounting hole is fixed to the end of the suspension member 36, and the bushing assembly 20 is compressed between the pair of arc-shaped members 26 in the longitudinal direction, that is, in the X-X direction. Mounting tube 4
0 is press-fitted.

A bolt 42 fixed to the vehicle body 38 is inserted as a pivot into the inner cylinder 24 of the bushing assembly 20.

A conventionally well-known spring collar 44 arranged in a row on the lower end surface of the elastic member 22 is fitted into the tip of the bolt 42, and a nut 46 is further screwed therein.

By occupying this nut 46, the bushing assembly 20
The inner cylinder 24 is fixed to the vehicle body 38.

A conventionally well-known buffer member 48 is fixed to a portion of the vehicle body 38 facing the end surface of the mounting tube 40.

When the bushing assembly 20 is press-fitted into the mounting tube 40, as shown in FIG. A void extending along the X direction is formed.

Therefore, between the inner cylinder 24 and the divided outer cylinders 26 and 26, the
The spring constant of the bushing assembly 20 for an external force acting perpendicularly to the -X direction is lower than the spring constant for an external force acting in the XX direction.

Furthermore, in the press-fitted state, the elastic body 34 disposed within the second groove portion 32 is compressively deformed between the groove surfaces 32a, 32a.

Therefore, in addition to the elastic repulsion force of the elastic member 22 acting in the X-X direction, the elastic repulsion force of the elastic body 34 acts as a force 7 that presses each arc-shaped member 26 toward the mounting tube 40.

As a result, the divided outer cylinder 26.2 consisting of the arc-shaped member 26
The frictional force between the outer cylinder 6 and the mounting cylinder 40 increases, so that the outer cylinder is not easily removed from the mounting cylinder 40.

In the bushing assembly according to the present invention, as described above, the elastic body 34 that provides an elastic repulsion force to the split outer cylinder when attached to the bushing assembly hole 40 is adapted to the elastic member that is elastically deformable. Groove surface 3 of the second groove portion formed
2a and 32a, and the divided outer cylinder 26
, 26, that is, the opposed surfaces of the divided outer cylinder.

Therefore, the elastic body 34 is not compressed between the divided surfaces of the divided outer cylinder 26, so that the dimensional accuracy between the divided surfaces of the divided outer cylinder 26 depends on the elastic repulsive force of the elastic body 34. There is no need to use, as the divided outer cylinder 26, a divided outer cylinder that has been processed with high precision as in the past.

Further, since both the elastic body 34 and the elastic member 22 that receives the elastic body are elastically deformable, the groove surface 32 of the second groove portion 32 where the elastic body 34 is disposed
The accuracy of the dimension between a and the thickness of the elastic body 34 in the dimension direction does not have a large influence on the elastic repulsive force of the elastic body 34 as in the conventional case.

Therefore, a predetermined elastic repulsion force can be obtained by the elastic body 34 without requiring high dimensional accuracy for any of the outer cylinder 26, the elastic member 22, and the elastic body 34 as in the conventional case. Therefore, a bushing assembly which has excellent vibration-proofing properties and does not fall off from a predetermined location can be obtained at a lower cost than conventional bushings.

Further, the elastic body 34 disposed between the divided surfaces of the outer cylinder 26 has a length dimension along the minor axis direction of the elastic member 22 that is larger than the plate thickness of the outer cylinder 26. Since it is a round-shaped elastic body, the bush mounting hole 4
The elastic body 34 receives a compressive force when attached to the
has a large pressure-receiving cross-sectional area, which makes it difficult for elastic fatigue to occur in the elastic body 34, and the elastic body exerts a predetermined elastic repulsion force even after long-term use.

Therefore, even after long-term use, the elastic repulsive force of the elastic body 34 can reliably prevent the bushing assembly from accidentally falling off from the bushing mounting hole.

Further, since the elastic body 34 is a block-shaped elastic body whose dimension along the minor axis direction of the elastic member 22 is larger than the plate thickness of the outer cylinder 26, the At the time of attachment to the bush attachment hole, the elastic body 34 touches the groove surfaces 32a, 32a of the second groove portion.
There is no buckling during the process, and assembly of the bushing assembly can be done quickly and easily.

Moreover, the elastic body 34 which is in a compressed state within the second groove portion compresses the first groove portion 30 in the width direction of the elastic member 22, that is, the X
When a strong external force in a direction perpendicular to the -X direction acts between the outer cylinder 26 and the inner cylinder 24, the outer cylinder 26 and the inner cylinder 24 are elastically deformed by the external force, thereby acting as a buffer against this external force.

Therefore, against an external force acting between the outer cylinder and the inner cylinder that completely compresses the first groove portion in the width direction, the elastic body 34 substantially reduces the effective pressure-receiving cross-sectional area of the elastic member. As a result, the durability of the elastic member against strong external forces as described above is improved, and the durability of the bushing assembly is also increased.

According to the experiments of the inventor of the present application, when an external force of 190 kg was applied in the axial direction of the conventional bushing assembly, the outer cylinder was pulled out from the mounting cylinder. According to the invention, even with an external force of 270 to 300 to 9, the outer cylinder would not be pulled out of the mounting cylinder.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a conventional bushing assembly;
2 and 3 are a perspective view and a cross-sectional view, respectively, showing the bushing assembly according to the present invention, and FIG. 4 is a longitudinal sectional view showing the assembled state of the bushing assembly according to the present invention, and FIG. FIG. 5 is a cross-sectional view taken along the line ■-■ shown in FIG. 22... Cylindrical elastic member, 24... Inner cylinder, 26... Divided outer cylinder (arc-shaped member), 28...
...Division groove, 30...First groove portion, 32.
...Second groove portion, 32a...Groove surface, 3
4...Elastic pair, 40...Button mounting hole (mounting tube).

Claims (1)

[Scope of utility model registration request] A cylindrical bushing assembly that is press-fitted into a bushing mounting hole, has an oval cross section as a whole, and has a pair of dividing grooves formed symmetrically with respect to its long axis, each of which runs approximately along the long axis direction. a cylindrical elastic member provided with a pair of dividing grooves consisting of a first groove portion extending along the minor diameter direction and a second groove portion extending from the groove portion in the short diameter direction and opening to the outer peripheral surface;
The elastic member includes an inner cylinder disposed to cover the inner circumferential surface of the elastic member, and a divided outer cylinder disposed to cover the outer circumferential surface of the elastic member to allow compressive deformation in the longitudinal direction of the elastic member. In the second groove portion, the length dimension along the minor axis direction of the elastic member is larger than the plate thickness dimension of the divided outer cylinder, and when the elastic member is press-fitted into the mounting hole, the second groove portion is opposite to the second groove portion. A cylindrical bushing assembly characterized in that a block-shaped elastic body is disposed that receives compressive force between the grooved surfaces and does not penetrate between the opposing surfaces of the divided outer cylinder.