JP2000337441A - Manufacture of vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the drawing rate of an elastic body to an approximately specified value when a drawing process after the rubbery elastic body is located at an internal part is executed on a deformed bracket by manufacturing through molding, such as, extrusion of an aluminum alloy. SOLUTION: Through molding, such as extrusion, of an aluminum alloy, a bracket 1 having a cylindrical coupling cylinder 2 and a mounting part 5 protruding integrally therewith is manufactured. By inserting an inner cylinder 3 in the coupling cylinder 2, a rubbery elastic body 5 is located therebetween. A plurality of moving die blades 6 are situated at the periphery of the bracket 1 and moved toward the center of the die. When each die blade 6 surrounds the whole periphery of the outer peripheral surface of the bracket 1, the coupling cylinder 2 is uniformly decreased in diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolator used for a bush provided on a mount of an automobile suspension or engine.

[0002]

2. Description of the Related Art In a suspension arm of an automobile, an engine mount, or the like, a bush is incorporated in a bracket to constitute a vibration isolator. As a conventional structure of this vibration isolator, a bush is formed by inserting an inner cylinder into an outer cylinder and vulcanizing and bonding rubber or the like between the outer cylinder and the inner cylinder to form an elastic body. You. This bush is drawn by a die to remove vulcanization shrinkage of the vulcanized rubber, the outer cylinder is compressed in the radial direction to reduce the diameter, and then a cylindrical bracket formed at one end of the arm It is fixed by being pressed into At the other end of the arm, an attachment body for attachment to the body is formed, or the same bracket as described above is formed.

[0003]

In the conventional structure, since the bush must be press-fitted into the bracket, both ends of the bracket must be tapered so that they can be inserted smoothly. In order to ensure the accuracy, the dimensional accuracy of the inner surface must be increased, and a machining step and equipment for the bracket are required, which increases the machining cost. In addition, there is a problem that the cycle time is increased due to the press-fitting step in manufacturing.

Accordingly, as a vibration isolator having such a structure that does not require press-fitting, a bracket made of an aluminum alloy having an inner cylinder and a connecting cylinder coaxially arranged at a distance outside the inner cylinder, Some rubber vulcanizing members are vulcanized and bonded between the connecting cylinder and the inner cylinder and integrally connect the two. This makes it possible to eliminate the press-fitting process and the bush outer cylinder.

[0005] Then, after the elastic body is vulcanized and bonded to the connecting cylinder, the connecting cylinder must be subjected to drawing using a die to reduce the diameter. However, since the bracket is formed by integrally extruding the cylindrical connecting cylinder and the arm, the bracket has an irregular shape in which a part of the circumference is a convex portion. When an aperture is applied to such a deformed bracket, a plurality of movable die blades are arranged on the outer periphery of the connecting cylinder except for the outer periphery of the arm. Therefore, a part of the outer periphery to which the arm is connected is not compressed and deformed, so that the distortion at the boundary between the connecting tube and the arm increases, and the variation in the inner diameter of the connecting tube increases. Therefore, since the squeezing rate of the elastic body differs in the circumferential direction, the characteristics of the elastic body change and durability decreases.

[0006] As another method of drawing a deformed bracket, a die in which a plurality of movable die blades and a fixed die blade are combined is used, and a fixed die blade is provided on a part of a convex portion such as an arm. The movable die blade is arranged around the connecting cylinder. In this case, since the fixed die blade cannot be squeezed, the bracket cannot be uniformly squeezed in the circumferential direction. As a result, the variation in the inner diameter of the connecting cylinder increases.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a method of manufacturing a vibration damping device capable of evenly squeezing an elastic body when drawing a deformed bracket having a convex portion formed on a part of the outer periphery. The aim is to provide a method.

[0008]

According to the present invention, there is provided a bracket having an irregular shape in which a convex portion is formed on a part of an outer periphery having a connecting cylinder and a mounting portion by extrusion or die casting of light metal. After manufacturing, a rubber-like elastic body made of rubber or elastomer is interposed between the connecting cylinder and the inner cylinder inserted therein, the bracket is drawn by a die, and the diameter of the connecting cylinder is reduced uniformly. Thus, a constant aperture is applied over the entire circumference of the elastic body.

Here, as a die used for drawing,
Use multiple movable die blades. The die blade is formed to have an inner peripheral surface corresponding to the shape of the bracket, and is arranged around the bracket. Then, by moving toward the die center and the die blade surrounding the entire outer peripheral surface of the bracket, the entire outer peripheral surface of the irregularly shaped bracket can be reduced in diameter. Therefore, the diameter of the inner peripheral surface of the connecting cylinder is also reduced uniformly, and the contraction ratio of the elastic body can be kept constant.

When a die having a fixed die blade and a plurality of movable die blades is used as the dice, the fixed die blade is disposed around the mounting portion, and the plurality of movable die blades are provided around the connecting cylinder. Deploy. Then, the movable die blade is moved toward the center of the die, and each die blade surrounds the entire outer peripheral surface of the bracket, whereby the diameter of the connecting cylinder can be reduced uniformly.

At this time, in order to keep the drawing ratio of the elastic body constant over the entire circumference, a bracket is arranged for each die blade so that the center of the die and the center of the connecting cylinder before drawing are offset. It is desirable to keep.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) As shown in FIG. 1, a suspension arm or a mount, which is a vibration isolator of the present embodiment, is a bracket 1 manufactured by extrusion molding or die casting of an aluminum alloy. And a rubber-like elastic body 4 interposed between the connecting cylinder 2 of the bracket 1 and the inner cylinder 3 inserted therein, and the bracket 1 is drawn by drawing in order to remove contraction of the elastic body 4. The diameter is reduced in the radial direction.

The bracket 1 has an irregular shape comprising a cylindrical connecting tube 2 and a mounting portion 5 integrally projecting from a part of the outer periphery of the connecting tube 2. This mounting part 5
However, the suspension arm is completed by being connected to the arm by welding or the like, or becomes a mount when directly attached to the body.

The elastic body 4 is the same as the conventional one, and is formed by inserting the inner cylinder 3 into the bracket 1, setting it in a molding die, and vulcanizing between the two.
The outer peripheral surface of the elastic body 4 is vulcanized and bonded to the inner peripheral surface of the connecting cylinder 2,
The inner peripheral surface of the elastic body 4 is vulcanized and bonded to the outer peripheral surface of the inner cylinder 3.
After the elastic body 4 is integrated with the connecting cylinder 2 and the inner cylinder 3 by vulcanization molding, the bracket 1 is subjected to drawing. In this drawing process, as shown in FIG.
Each dice blade 6 is arranged over the entire circumference of the bracket 1 using a dice including the movable dice blades 6 divided into two equal parts.

Here, the inner peripheral surface of the die blade 6 disposed around the connecting cylinder 2 of the bracket 1 is formed in an arc shape corresponding to the shape of the outer peripheral surface of the connecting cylinder 2 after drawing. The mounting portion 5 is arranged around the two die blades 6 so as to be sandwiched by the two die blades 6, and the inner peripheral surface of each of the die blades 6 is shaped to match the shape of the mounting portion 5.

Then, as shown in FIG.
The bracket 1 is compressed and deformed in the radial direction by moving the bracket 1 in synchronization with the center of the die. As a result, the inner peripheral surface of each die blade 6 comes into close contact with the entire outer peripheral surface of the bracket 1, and the diameter of the bracket 1, particularly the connecting cylinder 2, is reduced in the radial direction. The elastic body 4 is elastically deformed while being compressed in accordance with the diameter reduction, and the vulcanization shrinkage of the elastic body 4 is removed, so that the durability of the elastic body 4 is improved. In particular, in the drawing of the cylindrical connecting tube 2, the effect of the above method is exhibited.

Further, since a compressive force acts on the entire outer peripheral surface of the bracket 1, the diameter of the connecting cylinder 2 is reduced uniformly, and the drawing ratio of the elastic body 4 determined from the thickness of the elastic body 4 before and after the drawing is changed in the circumferential direction. Is almost uniform. At this time, the elastic body 4
Is suitable from the viewpoint of its characteristics and durability. Therefore, the shape of the dice is set so as to obtain such an aperture ratio.

(Second Embodiment) In this embodiment, the bracket 1 is the same as the above embodiment, but the dies for drawing are different. That is, as shown in FIG. 4, a die is used in which a plurality of movable die blades 6 that can move and a fixed die blade 7 that does not move are combined.

The movable die blade 6 is the same as described above, and the fixed die blade 7 covers the entire outer peripheral surface of the mounting portion 5 of the bracket 1 and partially covers the outer peripheral surface of the connecting cylinder 2. The width is at least 1/4 of the inner circumference of the die. The shape of the fixed die blade 7 is determined according to the shape of the mounting portion 5, and is narrowed or widened according to the size of the mounting portion 5 as shown in FIGS. In FIG. 5, reference numeral 8 denotes a hole, in which a spacer or a fixed die blade 9 is preferably installed.

As shown in FIG. 7, the center A of the die and the center B of the connecting cylinder 2 before drawing are offset. In other words, the bracket 1 before drawing is arranged so as to be offset from the die center A in the direction along the center line of the fixed die blade 7 as shown by the broken line.

When the die blades 6 and 7 are arranged so as to surround the entire circumference of the bracket 1, the clearance between the bracket 1 and the die blades 6 and 7 is not constant. However, by moving each movable die blade 6 synchronously toward the die center A, the bracket 1 is radially compressed and deformed while being displaced in the direction of the fixed die blade 7,
Finally, the center B of the bracket 1 coincides with the die center A, and the drawing is completed. Thereby, the bracket 1
The inner peripheral surfaces of the die blades 6 and 7 are in close contact with the entire outer peripheral surface of
The connecting cylinder 2 is reduced in diameter in the radial direction. The elastic body 4 is elastically deformed while being compressed in accordance with the diameter reduction, and the vulcanization shrinkage of the elastic body 4 is removed, so that the durability of the elastic body 4 is improved. At this time, it is preferable to perform drawing so that the drawing ratio of the elastic body 4 is 5 to 25%.

By disposing the die blades 6 and 7 over the entire circumference by using the fixed die blade 7 having a specific shape having a large width in the circumferential direction, the deformation of the bracket 1 during drawing is distorted. Instead, the shape after drawing is improved, and the variation in the inner diameter is reduced. Therefore, the squeezing rate of the elastic body 4 becomes substantially constant, and the elastic body 4 can obtain desired characteristics and durability. In addition, when the bracket 1 is offset when the fixed die blade 7 is used, a difference in pressure in the circumferential direction when pressure is applied to the bracket 1 by the movable die blade 6 is absorbed by the movement of the bracket 1, Ultimately, the diameter is reduced over the entire circumference of the bracket 1, and the diameter of the connecting cylinder 2 can be reduced uniformly, so that local distortion is eliminated and high quality manufacturing can be performed.

The present invention is not limited to the above embodiment, and many modifications and changes can be made within the scope of the present invention. As a material of the bracket, a light metal other than aluminum, such as a titanium alloy or a magnesium alloy, may be used.

[0024]

As is apparent from the above description, according to the present invention, a deformed bracket having a connecting cylinder and a mounting portion is manufactured by extruding a light metal such as an aluminum alloy or the like, and a rubber-like material is formed inside the connecting cylinder. After interposing an elastic body,
Using a die consisting of multiple die blades according to the shape of the bracket, drawing is performed so as to surround the entire outer peripheral surface of the bracket, so changing the shape of the die blade does not complicate the die structure Alternatively, the diameter of the connecting cylinder of the bracket can be reduced uniformly. In particular, when the connecting cylinder is a cylinder, the shape after drawing is stable without being distorted, so that a high quality product can be provided.

Further, by using a movable die blade as a die and moving the die toward the center of the die, the entire outer peripheral surface of the bracket can be reduced in diameter. Alternatively, a movable die blade is arranged in the connecting cylinder, a fixed die blade is arranged in the mounting portion, and a bracket is provided for each die blade so that the center of the die and the center of the connecting cylinder before drawing are offset. By moving the movable die blade toward the center of the die, each die blade can surround the entire outer peripheral surface of the bracket to reduce the diameter of the bracket. Therefore, the diameter of the connecting cylinder can be reduced uniformly, the contraction ratio of the elastic body can be easily made constant over the entire circumference, the durability of the elastic body increases, and the desired characteristics are not impaired. Can be demonstrated.

[Brief description of the drawings]

FIG. 1 shows a bracket according to a first embodiment of the present invention,
(A) is a plan view, (b) is a sectional view.

FIG. 2 shows a die before drawing.

FIG. 3 is a diagram showing a die after drawing.

FIG. 4 is a diagram showing a die according to a second embodiment.

FIG. 5 is a view showing a die for a bracket having another shape.

FIG. 6 is a view showing a die for a bracket having another shape.

FIG. 7 is a view for explaining positions of brackets before and after drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bracket 2 Connecting cylinder 3 Inner cylinder 4 Rubbery elastic body 5 Mounting part 6 Movable die blade 7 Fixed die blade A Die center B Center of connecting cylinder before drawing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J048 AA01 BA19 DA06 EA01 EA16 3J059 AB12 AD05 BA42 BC01 BD07 CB15 EA02 EA03 EA17 GA02 GA09

Claims (5)

[Claims] 1. A bracket having a connecting cylinder and a mounting portion is manufactured by extrusion molding or die casting of light metal, and a rubber-like elastic body is interposed between the coupling cylinder and an inner cylinder inserted therein. Using a die having a plurality of movable die blades when drawing the bracket, disposing the die blade around the bracket and moving the die blade toward the center of the die, wherein the die blade is an outer peripheral surface of the bracket. A method for manufacturing an anti-vibration device, wherein the diameter of the connecting cylinder is reduced uniformly by surrounding the entire circumference. 2. A bracket having a connecting cylinder and a mounting portion is manufactured by extrusion molding or die casting of light metal, and after a rubber-like elastic body is interposed between the coupling cylinder and an inner cylinder inserted therein. When drawing the bracket, a die having a fixed die blade and a plurality of movable die blades is used, a fixed die blade is arranged around the mounting portion, and a plurality of movable die blades are arranged around the connecting cylinder. Manufacturing the vibration isolator, wherein the movable die blade is moved toward the center of the die, and each die blade surrounds the entire outer peripheral surface of the bracket to uniformly reduce the diameter of the connecting cylinder. Method. 3. The method according to claim 2, wherein the center of the die and the center of the connecting cylinder before drawing are offset. 4. The method according to claim 2, wherein a width of the fixed die blade in the circumferential direction is equal to or more than ４ of an inner peripheral surface formed by each die blade. 5. The drawing ratio of the elastic body by drawing is 5-2.
The method for manufacturing a vibration isolator according to claim 1, wherein the amount is set to 5%.