JP2003106359A - Antivibration bush and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antivibration bush of small and light weight, with the surface pressure on the end surface of inner tube reduced. SOLUTION: An outer tube 2 is provided outside an inner tube 1 with a space which comprises a swollen part 7 swelling in the direction perpendicular to an axis near the central part in axial direction. A rubber-like elastic body is interposed between the inner tube 1 and the outer tube 2 for vulcanization, and after that, the end face of inner tube 1 in axial direction is press-contacted in axial direction by a press-contacting jig 8, so that a one-side enlarged part 5, where the wall thickness at the end of inner tube 1 is larger than the other part, is formed to enlarge the area of the end face of inner tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration bush incorporated in, for example, a part of a suspension mechanism of an automobile to control vibrations transmitted from a wheel side to a vehicle body side.

[0002]

2. Description of the Related Art Generally, in an automobile such as a passenger car, a suspension mechanism or an engine support mechanism is used to control vibration transmitted from a wheel side to a vehicle body side or vibration transmitted from an engine side to a vehicle body side. An anti-vibration bush is incorporated in the part.

FIG. 7 shows an example of a conventional anti-vibration bush.
This anti-vibration bush is a so-called bulge type anti-vibration bush, and is a cylindrical inner cylinder 1 having the same cross section in the axial direction.
01, a substantially hemispherical bulging portion 104 fixed to the outer peripheral surface near the center in the axial direction, a cylindrical outer cylinder 102 arranged at a space outside thereof, an inner cylinder 101 and an outer cylinder. And a rubber-like elastic body 103 that is interposed between the rubber-like elastic body 103 and the bulging portion 104. With this configuration, a predetermined spring characteristic is set in the axial direction and the axis-perpendicular direction of the vibration isolation bush, and in the twisting direction in which the central axes of the inner and outer cylinders are relatively inclined. Here, the "axial direction" means the direction of the axis passing through the center of the inner cylinder, and the "axial right angle direction" means the direction orthogonal to the axial direction (the same meaning is used in the following description).

That is, in the vibration-proof bush shown in FIG. 7, the rubber-like elastic body 103 covering the outer peripheral side of the bulging portion 104.
The thickness in the direction perpendicular to the axis of is set to be thin near the center of the axis and thick near both ends of the axis.
The vibration-proof bushing is set so that the spring constant in the direction perpendicular to the axis is large, the spring constant in the twisting direction is small, and the spring constant is a predetermined spring constant.

[0005]

By the way, in the vibration-proof bush as shown in FIG. 7, both end surfaces 105 of the inner cylinder 101 are sandwiched by mounting members such as brackets, or the inner cylinder 1
With only one end surface 105 of 01 abutting the mounting member, the shaft member is inserted inside to be fastened and fixed to the mounting member, and the outer cylinder 102 is fixed to another member, thereby The members are connected in a vibration-proof manner.

In such an anti-vibration bush, when the area of the end surface of the inner cylinder is small, the surface pressure due to the fastening with the mounting member becomes large, and the mounting member may be depressed or the outer end of the inner cylinder may buckle. There is.

Therefore, in order to solve this, it can be considered to increase the outer diameter of the inner cylinder to increase the area of the end surface of the inner cylinder. However, when the outer diameter of the inner cylinder is increased, in order to maintain the spring constants of the vibration-proof bushing at the respective prescribed values,
Since the rubber-like elastic body that fulfills the vibration damping function must maintain the above-mentioned predetermined thickness, the outer cylinder must be made larger by the outer diameter of the inner cylinder, and as a result, There is a problem that the outer diameter becomes large.

Further, when the outer diameter of the inner cylinder is increased to increase the area of the end surface of the inner cylinder, the weight of the inner cylinder is increased, and accordingly, the weight of the entire vibration damping bush is increased. is there.

In view of the above problems, the present invention makes it possible to reduce the surface pressure of the end surface of the inner cylinder without changing the weight of the inner cylinder in a so-called bulge type vibration damping bush while maintaining the size and weight reduction. The purpose is to provide an anti-vibration bush.

[0010]

In order to achieve the above object, the present invention provides a cylindrical inner cylinder having a bulging portion which bulges in the direction perpendicular to the axis in the vicinity of the central portion in the axial direction, and the inner cylinder. A cylindrical outer cylinder arranged at a distance to the outside and a rubber-like elastic body interposed between the inner cylinder and the outer cylinder are provided, and the inner cylinder has a wall thickness of its end portion. The present invention provides a vibration-isolating bush characterized in that a diameter-expanded portion set to be larger than other portions is formed.

According to this structure, since the enlarged diameter portion having a large wall thickness is formed at the end portion of the inner cylinder, it is not necessary to increase the outer diameter of the entire inner cylinder. By increasing the area of the cylinder end surface, the surface pressure of the inner cylinder end surface due to the fastening with the mounting member can be reduced.

The expanded diameter portion can be formed by machining such as cutting, but after the rubber-like elastic body is vulcanized between the inner and outer cylinders, the end surface of the inner cylinder is pressed in the axial direction. If it is formed in this way, it is preferable in that the expanded diameter portion can be easily formed by post-processing.

That is, according to the present invention, in addition to the structure of claim 1, the inner cylinder is made of a metal member, and the enlarged diameter portion is formed by pressing the end of the inner cylinder in the axial direction. Anti-vibration bushes can also be provided.

The expanded diameter portion can be formed not only on one end side of the inner cylinder but also on both end portions. That is, in the present invention, it is also possible to provide a vibration-proof bush in which the expanded diameter portion is formed at both ends of the inner cylinder.

Further, referring to the structure of the inner cylinder, the bulging portion bulging in the direction perpendicular to the axis near the central portion in the axial direction of the inner cylinder is
It is possible to employ either a mode in which the outer peripheral surface of the inner cylinder is cut and formed integrally with the inner cylinder, as in the case of the expanded diameter portion, or a mode in which the inner cylinder is formed separately from the inner cylinder and the two are joined together.

When the inner cylinder and the bulging portion are formed separately, the material may be either metal or synthetic resin. When it is made of synthetic resin, the weight of the bulging portion can be reduced.

The synthetic resin in this case includes polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, acrylonitrile-styrene resin (AS resin), ABS, acrylic resins, and other general thermoplastic resins, Polyamides, polycarbonates, polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), thermoplastic resins called engineering plastics such as polyacetal and modified polyphenylene ether, polyphenylene sulfide, polyether ether ketone (PEE)
K), polyarylate, polysulfone, polyether sulfone, polyketone sulfide, polyether imide, polytetrafluoroethylene, aromatic polyester, polyamino bismaleimide, resins called super engineering plastics such as triazine resins can be exemplified.

Among these, nylon 6 and nylon 6
Polyamides such as 6 and the like, polyethylene terephthalate, polybutylene terephthalate, and polyphenylene sulfide are particularly preferable. These resins may be fixed to the outer peripheral surface of the inner cylinder by injection molding or the like.

That is, in the present invention, it is possible to provide a vibration-proof bushing in which the bulging portion is made of synthetic resin and fixed to the outer peripheral surface of the inner cylinder, and the synthetic resin is polyethylene terephthalate. An anti-vibration bush made of polybutylene terephthalate, polyphenylene sulfide or polyamide can also be provided.

In the present invention, as a method of manufacturing the vibration-proof bush having the above-described structure, first, a space is provided outside a cylindrical inner cylinder having a bulging portion that bulges in the direction perpendicular to the axis near the central portion in the axial direction. The outer cylinder, and the rubber-like elastic body is interposed between the inner cylinder and the outer cylinder for vulcanization molding, and after the vulcanization molding, one end of the inner cylinder is axially moved by a pressure welding jig. It is possible to provide a method for manufacturing an anti-vibration bush, which is characterized in that the one side expanded diameter portion in which the end wall thickness of the inner cylinder is larger than that of the other portion is formed by pressing.

Further, in the case of forming the expanded diameter portion at both ends of the inner cylinder, in the present invention, after forming the expanded diameter portion on one end side of the inner cylinder, the other end portion of the inner cylinder is pressed by a pressure welding jig. It is possible to provide a method for manufacturing a vibration-isolating bush, which is pressed in the axial direction to form the other-side expanded diameter portion in which the end wall thickness of the inner cylinder is larger than the other portions.

According to the above-mentioned structure, as described above, the rubber-like elastic body is vulcanized by forming the rubber-like elastic body between the inner and outer cylinders by vulcanization molding and then pressing the end surface of the inner cylinder in the axial direction. The expanded diameter portion can be easily formed by post-processing after molding. Moreover, when the anti-vibration bush is removed from the molding die, since there is no enlarged diameter portion, the die cutting work can be easily performed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An anti-vibration bush according to an embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view of an anti-vibration bush according to the present invention, and FIG. 2 is II- of FIG.
It is a II sectional view.

This anti-vibration bush includes an inner cylinder 1 made of metal,
An inner cylinder 1 is provided with an outer cylinder 2 which is arranged outside at a right angle to the axis, and a ring-shaped rubber-like elastic body 3 which is interposed between the inner cylinder 1 and the outer cylinder 2. The inner cylinder 1 and the outer cylinder 2 are attached to different members, respectively, so that both members are vibration-proofly coupled.

The inner cylinder 1 is made of, for example, steel, and has a covering portion 4 formed in the central portion in the axial direction and covered with the rubber-like elastic body 3, and on both axial sides of the covering portion 4. The diameter-enlarged portion 5 whose wall thickness is set larger than that of the covering portion 4 is continuously formed into a cylindrical shape. Then, in a state where the end surface 6 of the expanded diameter portion 5 is sandwiched between mounting members such as brackets, or only the end surface 6 of one expanded diameter portion 5 is in contact with the mounting member,
A shaft member such as a bolt is inserted through a through hole in the center of the inner cylinder 1 and fastened and fixed to a mounting member.

The inner and outer diameters of the coating portion 4 are constant in the axial direction, that is, they are formed in the same cross section in the axial direction. The enlarged diameter portion 5 has an inner diameter that is substantially the same as that of the covering portion 4, an outer diameter that is larger than the outer diameter of the covering portion 4, and is formed to increase the contact area of the end surface 6 with the mounting member. ing. As will be described later, the expanded diameter portion 5 is formed by pressing the end surface of the inner cylinder having the same cross section in the axial direction.

Further, the inner cylinder 1 has a bulging portion 7 made of synthetic resin fixed to the outer peripheral surface of the covering portion 4 so as to bulge into a substantially spherical shape in the direction perpendicular to the axis. The bulging portion 7 can be molded with many kinds of synthetic resins, but it is particularly preferable to form it with polyamide such as nylon 6 or nylon 66, polyethylene terephthalate, polybutylene terephthalate, or polyphenylene sulfide.

The outer cylinder 2 is made of, for example, a steel cylinder, and is press-fitted and fixed in the opening of the mounting member. The inner diameter and the outer diameter of the outer cylinder 2 are larger than the outer diameter of the central portion of the bulging portion 7 and are substantially constant in the axial direction, and the axial length thereof is the inner cylinder 1.
It is set to be slightly longer than the covering portion 4 and shorter than the axial length of the inner cylinder so that the rubber-like elastic body 3 can be housed inside.

The rubber-like elastic body 3 is interposed between the inner cylinder 1 and the outer cylinder 2 by vulcanization so as to cover the outer peripheral surface of the bulging part 7, and the bulging part outside the inner cylinder 1. Due to the effect of the thickness of No. 7, the thickness is set to be thin in the vicinity of the center in the axial direction and thick in the vicinity of both ends in the axial direction.

The rubber-like elastic body 3 has a large spring constant in the direction perpendicular to the axis by being thinned near the center in the axial direction, and has a spring constant in the twisting direction by being thickened near both ends in the axial direction. It will be set small. In order to set the spring constants of the three axes in the axial direction, the axis-perpendicular direction, and the twisting direction to desired values, the rubber-like elastic body 3 is, for example, as shown in FIG. A mode in which the continuous recesses 3a are formed can also be adopted.

A method of manufacturing this vibration damping bush will be described. First, as shown in FIG. 3, an inner cylinder 1 made of steel and having a constant inner diameter and outer diameter in the axial direction, that is, the same cross-sectional shape is prepared. Considering that the expanded diameter portion 5 is formed on both ends of the inner cylinder 1 by post-processing, an inner cylinder longer than the product length of the vibration isolation bush is prepared. Then, the bulging portion 7 is bulged into a substantially hemispherical shape by injecting, for example, a heat-melted synthetic resin onto the outer peripheral surface near the axial center of the inner cylinder 1
Stick to.

Next, as shown in FIG. 4, the outer cylinder 2 is arranged outside the inner cylinder 1 with a space therebetween, and the rubber-like elastic body 3 is arranged between the inner and outer cylinders 1 and 2 so as to cover the bulging portion 7. And the rubber-like elastic body 3 is vulcanized and molded, and the inner and outer cylinders 1 and 2 are integrated by the rubber-like elastic body 3.

Next, the vulcanized molded product is taken out from the vulcanized mold and, as shown in FIG. 5, a pressure welding jig 8 is attached to one end (upper end in the drawing) of the inner cylinder 1. Rotate while pressing from the direction. Then, one end portion of the inner cylinder 1 is plastically deformed with contraction in the axial direction, and the end portion has a wall thickness of the covering portion 4.
A larger diameter conical tubular diameter portion 5 is formed.

Here, as shown in FIG. 5, the pressure welding jig 8 is made of steel having a higher strength than the inner cylinder 1, and the pressure welding surface 10 is formed at the end of the jig body 9 having a circular cross section. This pressure contact surface 10
Is a part of a conical surface, and a projection 11 having a circular cross section is formed in the center thereof.

The protrusion 11 of the pressure welding jig 8 is inserted from one end of the inner cylinder 1 into the central hole of the inner cylinder 1, and the conical pressure contact surface is aligned with the one end surface 6 of the inner cylinder 1. Attach the pressing jig 8 to the protrusion 1
When the rotation is interlocked around the apex of 1, the entire end surface 6 of the inner cylinder 1 is pressed and axially pressed to be plastically deformed, and its outer diameter is expanded. In addition, the inner diameter of the one end is equal to that of the protrusion 1
Since it is pressed outward by 1, the diameter is not reduced and only the outer diameter is expanded.

After forming the expanded diameter portion 5 at one end of the inner cylinder 1, the inner cylinder 1 is inverted to form the expanded diameter portion 5 at the other end of the inner cylinder 1 in the same manner. A vibration-proof bushing having expanded diameter portions 5 at both ends of 1 is completed.

According to such a method for manufacturing the vibration-proof bush, since the expanded diameter portions 5 are formed at both ends of the inner cylinder 1 after the rubber-like elastic body 3 is vulcanized and molded, the die-cutting work during vulcanization molding is performed. Can be done easily.

The present invention is not limited to the above-mentioned embodiment, and appropriate modifications can be made within the scope of the present invention. For example, as shown in FIG.
The bulging portion 12 formed on the outer peripheral surface of the inner cylinder 13 can be integrally formed of the same material as the inner cylinder 13. Also in this case, it is preferable that the expanded diameter portion 15 of the inner cylinder 13 is formed after the rubber-like elastic body is vulcanized and molded.

[0039]

As is apparent from the above description, according to the present invention, since the enlarged diameter portion having the large wall thickness is formed at the end portion of the inner cylinder, it is not necessary to increase the outer diameter of the entire inner cylinder, and the size is reduced. The weight can be reduced, the durability of rubber can be improved, and the area of the inner cylinder end surface can be increased to reduce the surface pressure of the inner cylinder end surface due to the fastening with the mounting member.

In this case, if the expanded diameter portion is formed by vulcanizing and molding the rubber-like elastic body and then press-contacting the end surface of the inner cylinder in the axial direction, the expanded diameter portion can be easily formed by post-processing. And has an advantage that die cutting at the time of vulcanization molding can be easily performed.

[Brief description of drawings]

FIG. 1 is a perspective view of an anti-vibration bush according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view showing a state in which a single inner cylinder is cut in the axial direction.

FIG. 4 is a sectional view showing a state in which the vibration-proof bush before the inner cylinder is expanded is cut in the axial direction.

FIG. 5 is a sectional view of the vibration-proof bush showing how the outer end of the inner cylinder is expanded.

FIG. 6 is a cross-sectional view showing a state in which an anti-vibration bush formed by inflating the vicinity of an axial center of an inner cylinder according to another embodiment of the present invention is axially cut.

FIG. 7 is a cross-sectional view showing a state in which a conventional vibration isolation bush is axially cut.

[Explanation of symbols]

1 inner cylinder 2 outer cylinder 3 Rubber-like elastic body 4 Cover 5 Expanded part 6 end faces 7 bulge 8 Pressure welding jig 12 bulge

Claims (8)

[Claims] 1. A cylindrical inner cylinder having a bulging portion that bulges in the direction perpendicular to the axis near the central portion in the axial direction, and a cylindrical outer cylinder arranged outside the inner cylinder with a space. And a rubber-like elastic body interposed between the inner cylinder and the outer cylinder, wherein the inner cylinder is formed with a diameter-expanded portion in which a wall thickness of an end thereof is set to be larger than that of other portions. Anti-vibration bush that has been characterized. 2. An anti-vibration bush according to claim 1, wherein the inner cylinder is made of a metal member, and the enlarged diameter portion is formed by pressing the end surface of the inner cylinder in the axial direction. 3. The vibration-isolating bush according to claim 1, wherein the expanded diameter portion is formed at both end portions of the inner cylinder. 4. The vibration-proof bush according to claim 1, wherein the bulging portion is made of synthetic resin and is fixed to the outer peripheral surface of the inner cylinder. 5. The vibration isolation bush according to claim 4, wherein the synthetic resin is polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide or polyamide. 6. An inner cylinder, an outer cylinder arranged outside the inner cylinder with a space therebetween, and a rubber-like elastic body interposed between the inner cylinder and the outer cylinder. The cylinder is composed of a covering portion covered with the rubber-like elastic body and both end portions located on both sides in the axial direction thereof, and a bulging portion bulging in the axis-perpendicular direction is provided on the outer periphery of the covering portion, A vibration-isolating bush characterized in that at least one of the both end portions is an expanded diameter portion having a larger wall thickness than the covering portion. 7. An outer cylinder is arranged outside the cylindrical inner cylinder having a bulge portion bulging in the direction perpendicular to the axis near the central portion in the axial direction, and the outer cylinder and the inner cylinder are arranged. The rubber-like elastic body is interposed between the vulcanization molding, and after the vulcanization molding, one end surface of the inner cylinder in the axial direction is pressed in the axial direction by a pressing jig so that the end wall thickness of the inner cylinder is reduced. A method for manufacturing an anti-vibration bush, comprising forming a one-side expanded diameter portion that is larger than the other portions. 8. An enlarged diameter portion is formed on one end side of the inner cylinder, and then the other axial end surface of the inner cylinder is pressed in the axial direction by a pressing jig.
The method for manufacturing a vibration-isolating bush according to claim 7, wherein the other-side expanded diameter portion in which the end wall thickness of the inner cylinder is larger than the other portions is formed.