JPH11173371A - Cylindrical bush and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stopper having high dimensional accuracy even if its shape becomes complicated. SOLUTION: A barlike member 17 having a fixed longitudinal cross section is formed by extrusion molding of aluminum. This barlike member 17 is cut to a predetermined length to form a stopper 4 to be press-fitted into an inner cylinder. Consequently, it is possible to provide the stopper 4 having high dimensional accuracy, even if a shape of a contact face of the stopper 4 is complicated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cylindrical bush, and more particularly, to a stopper fixed to an inner cylinder.

[0002]

2. Description of the Related Art A cylindrical bush is provided on a vehicle suspension or the like to prevent vibration transmission. The general configuration of a general cylindrical bush is such that a cylindrical inner cylinder is disposed inside a cylindrical outer cylinder, and the outer peripheral surfaces at both ends of the inner cylinder and the inner peripheral surfaces at both ends of the outer cylinder are substantially circular. They are connected by an annular rubber elastic body. As shown in FIG. 8, a plate-like stopper 31 having a through-hole 36 substantially equal to the outer diameter of the inner cylinder 32 is press-fitted and fixed to the center of the inner cylinder. The tip of the stopper 31 protruding in the 180-degree symmetrical direction about the through hole 36 is close to the inner peripheral surface of the outer cylinder (not shown). As shown in FIGS. 9 and 10, a projecting portion 37 is formed at the center of the contact surface 34 at the tip end portion, which protrudes in a substantially rectangular shape toward the inner peripheral surface of the outer cylinder (not shown). The contact surface 34 is covered with a rubber elastic member 33.

When the inner cylinder 32 receives a load,
While deforming toward the inner peripheral surface of the outer cylinder (not shown) while elastically deforming the substantially annular rubber elastic body connecting the outer cylinder and the inner cylinder, if the amount of displacement is large, the protrusion 37 Abuts on the inner peripheral surface of the outer cylinder (not shown) via the rubber elastic member 33 to restrict excessive elastic deformation of the rubber elastic body.

In such a conventional cylindrical bush, the height of the protrusion 37 of the contact surface 34, that is, the dimension A in FIG. 9 is tuned so that the rubber elastic member 33 is not shown. The dynamic spring characteristics and the durability of the rubber elastic member 33 when the rubber elastic member 33 is deformed by contacting the inner peripheral surface of the cylinder are determined. That is, the dimensional accuracy of the contact surface 34 of the stopper 31 is required for performance. In order to improve the dynamic spring characteristics and durability of the stopper 31,
5, the curvature of the contact surface 34 is reduced and the shape of the contact surface 34 is complicated.

A method for manufacturing such a stopper 31 is as follows.
A method of manufacturing by punching by press working (for example, see Japanese Patent Application Laid-Open No. 7-71511), a method of molding with a resin (for example, see Japanese Utility Model Publication No. 8-1309), and a method of manufacturing by casting or die casting. Methods are known.

[0006]

However, as in the prior art, when the stopper 31 is manufactured by press working, if the shape of the contact surface 34 becomes complicated, sufficient dimensional accuracy cannot be obtained by press punching, and the stopper 31 cannot be provided. If the width dimension B of 31 is large, there is a problem that it cannot be processed.

In the case where the stopper 31 is made of a resin, there is a possibility that a crack may be formed when a large load is applied to the stopper 31.

When the stopper 31 is manufactured by casting or die casting, the cost becomes extremely high.

[0009]

Therefore, according to the present invention, a metal outer cylinder, a metal inner cylinder located inside the outer cylinder, and a through-hole corresponding to the outer shape of the inner cylinder are provided. Has,
A stopper fixed to the inner cylinder by the through hole;
A rubber elastic body interposed between the outer cylinder and the inner cylinder,
Wherein the stopper is formed by extrusion of aluminum. As a result, a stopper with high dimensional accuracy can be obtained even if the shape of the stopper becomes complicated.

According to a second aspect of the present invention, there is provided a metal outer cylinder, a metal inner cylinder positioned inside the outer cylinder, and a through-hole corresponding to the outer shape of the inner cylinder. In a method for manufacturing a cylindrical bush having a stopper fixed to an inner cylinder and a rubber elastic body interposed between the outer cylinder and the inner cylinder, the stopper is made of aluminum and has a predetermined constant cross section. After being extruded into a rod shape having the following shape, it is cut into a required thickness and fixed to the inner cylinder.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings. The cylindrical bush 1 according to the present invention comprises:
As shown in FIG. 1 and FIG. 2, it is roughly composed of an outer cylinder 2, an inner cylinder 3, a stopper 4 and a rubber elastic member 5. The outer cylinder 2 is made of metal, is formed in a substantially cylindrical shape having a constant thickness, and has a bent portion which is bent short toward the radially inner peripheral side of the outer cylinder 2 at the openings 6 at both ends. 7 are formed.

The inner cylinder 3 is made of metal, has a substantially cylindrical shape with a constant thickness, is formed with a diameter smaller than the inner diameter of the outer cylinder 2, and is located coaxially with the outer cylinder 2. And this inner cylinder 3
The substantially plate-shaped stopper 4 made of aluminum and having a circular through-hole 8 substantially equal to the outer diameter of the inner cylinder 3 is press-fitted and fixed to a central portion in the longitudinal direction of the inner cylinder 3.

The stopper 4 has a pair of stoppers 4a projecting in a 180-degree symmetrical direction about the through hole 8, and a contact surface 1 at the tip of the stopper 4a.
5 is in close proximity to the inner peripheral surface of the outer cylinder 2. The contact surface 15 is curved along the curvature of the inner peripheral surface of the outer cylinder 2 and has a substantially rectangular projection 1 at the center.
6 are formed, and the projecting portions 16 are so close that they do not contact the inner peripheral surface of the outer cylinder 2.

The rubber elastic member 5 is vulcanized and bonded to the inner cylinder 3 into which the stopper 4 is press-fitted.

The rubber elastic members 5 are located at both ends of the inner cylinder 3 and have a substantially disk-shaped main elastic portion 5a which is larger in diameter than the stopper 4 and a stopper covering portion 5b which covers the outer surface of the stopper 4. And, it consists of. A substantially cylindrical metal ring 9 is provided on the outer peripheral surface of the rubber elastic member 5. The metal ring 9 has an opening at the center corresponding to the stopper 4 and is pressed tightly into the outer cylinder 2. And
Both end edges 7 of the outer cylinder 2 are caulked inward, thereby being integrated with the metal ring 9.

A space 14 defined by the main elastic portion 5a and the outer cylinder 2 is sealed from the outside, and a fluid such as silicon oil is sealed inside.

The stopper 4 is formed through two steps. That is, as shown in FIG. 3, in the first step, the aluminum base material is formed into a rod-like member 17 having a constant vertical cross section by extrusion molding. Next, in a second step, the rod-shaped members 17 are cut to a predetermined length, and individually become the stoppers 4. That is, the rod-shaped member 17 obtained by extrusion molding is cut into a desired length, and is pressed into the inner cylinder 3 as the stopper 4 as shown in FIG.

In the cylindrical bush 1 constructed as described above, the stopper 4 is previously formed into a desired outer shape by extrusion of aluminum.
Even if the contact surface 15 of the stopper 4 facing the inner peripheral surface has a complicated shape, it can be formed with high precision, and the cost can be reduced as compared with the case where the stopper 4 is manufactured individually by casting or die casting. Becomes

Further, since the stopper 4 is made of aluminum, a higher strength can be obtained as compared with resin, and the weight can be reduced as compared with iron.

The method of fixing the inner cylinder 3 and the stopper 4 is as follows.
After that, the opening of the through hole 8 and the outer surface of the inner cylinder 3 may be welded. Alternatively, after the stopper 4 is inserted into the inner cylinder 3, it may be fixed by caulking to reduce the diameter of the through hole 8.

In order to prevent rotation between the inner cylinder 3 and the stopper 4, as shown in FIGS. 5 and 6, the outer peripheral shape of the inner cylinder 3 is formed in a non-circular shape, and the stopper 4 penetrates. Hole 8
May be formed in a non-circular shape corresponding to this.

As shown in FIG. 7, a mesh-like knurling process 13 is applied to the outer peripheral surface of the inner cylinder 3 formed in a cylindrical shape at a position where the stopper 4 is fixed, and caulking is performed after the stopper 4 is inserted. , The inner cylinder 3 and the stopper 4
Can reliably be prevented from rotating.

The present invention is not limited to the embodiment described above, but is applicable to a cylindrical bush in which no fluid is sealed inside the cylindrical bush 1.

[0024]

As described above, in the cylindrical bush according to the present invention, since the stopper is formed by extrusion molding of aluminum, the contact surface facing the inner peripheral surface of the outer cylinder has a complicated shape. However, the stopper can be formed with high accuracy, and the cost can be reduced as compared with the case where the stopper is manufactured by casting or die casting. In addition, since the stopper is made of aluminum, it is possible to obtain higher strength than a resin, and it is possible to reduce the weight as compared with iron.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a cylindrical bush according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view of a stopper of the cylindrical bush according to the present invention.

FIG. 4 is a perspective view when the stopper of FIG. 3 is pressed into an inner cylinder and fixed.

FIG. 5 is a perspective view of an inner cylinder in a different embodiment in which the inner cylinder is formed in a non-cylindrical shape.

FIG. 6 is a perspective view of a stopper corresponding to the inner cylinder of FIG. 5;

FIG. 7 is a perspective view of an inner cylinder in a different embodiment in which knurling is performed on the inner cylinder.

FIG. 8 is a side view of a conventional example in which a stopper is attached to an inner cylinder.

FIG. 9 is a cross-sectional view of the stopper of FIG. 8 covered with a rubber elastic member.

FIG. 10 is a front view of FIG. 8;

[Explanation of symbols]

 3 ... Inner cylinder 4 ... Stopper 5 ... Rubber elastic member 5a ... Main elastic part 5b ... Stopper covering part

Claims (2)

[Claims] 1. A metal outer cylinder, a metal inner cylinder located inside the outer cylinder, and a through hole corresponding to an outer shape of the inner cylinder, the outer cylinder being fixed to the inner cylinder by the through hole. A cylindrical bush having a stopper, and a rubber elastic body interposed between the outer cylinder and the inner cylinder, wherein the stopper is formed by extrusion molding of aluminum. bush. 2. A metal outer cylinder, a metal inner cylinder positioned inside the outer cylinder, and a through hole corresponding to the outer shape of the inner cylinder, the outer cylinder being fixed to the inner cylinder by the through hole. In a method for manufacturing a cylindrical bush having a stopper and a rubber elastic body interposed between the outer cylinder and the inner cylinder, the stopper is made of aluminum and extruded into a rod shape having a predetermined constant cross section. A method for producing a cylindrical bush, comprising cutting the molded product into a required thickness, and fixing the molded product to the inner cylinder.