JP3648607B2 - Anti-vibration bush and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anti-vibration bush that is incorporated in, for example, a part of a suspension mechanism of an automobile and controls vibrations transmitted from a wheel side to a vehicle body side.
[0002]
[Prior art]
Generally, in automobiles such as passenger cars, vibration control transmitted from the wheel side to the vehicle body side, vibration transmitted from the engine side to the vehicle body side, etc. is controlled in order to control vibrations in a part of the suspension mechanism and engine support mechanism. Bush is incorporated.
[0003]
FIG. 6 shows an example of a conventional anti-vibration bush. This anti-vibration bush is a so-called bulge-type anti-vibration bush, which is a cylindrical inner cylinder 101 having the same cross section in the axial direction, and a substantially hemispherical bulge fixed to the outer peripheral surface near the center in the axial direction. A rubber-like elastic body interposed between the inner cylinder 101 and the outer cylinder 102 so as to cover the bulging portion 104. 103. And by this structure, it sets so that a predetermined | prescribed spring characteristic may be acquired in the axial direction of an anti-vibration bush, an axial perpendicular direction, and the center axis | shaft of an inner and outer cylinder inclining relatively. Here, the “axial direction” refers to the direction of the axis passing through the center of the inner cylinder, and the “axial perpendicular direction” refers to the direction orthogonal to the axial direction (used in the same meaning in the following description).
[0004]
That is, in the anti-vibration bush shown in FIG. 6 , the thickness of the rubber-like elastic body 103 covering the outer peripheral side of the bulging portion 104 is thin near the center in the axial direction and thick near both ends in the axial direction. Accordingly, the anti-vibration bush 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 a predetermined spring constant is obtained in the axial direction.
[0005]
[Problems to be solved by the invention]
By the way, in the vibration isolating bush as shown in FIG. 6 , the both end surfaces 105 of the inner cylinder 101 are sandwiched between mounting members such as brackets, or only one end surface 105 of the inner cylinder 101 is in contact with the mounting member. In this state, the shaft member is inserted inside and fastened and fixed to the mounting member, and the outer cylinder 102 is fixed to another member, so that both members are connected in a vibration-proof manner.
[0006]
In such an anti-vibration bushing, when the area of the end surface of the inner cylinder is small, the surface pressure due to fastening with the mounting member increases, and there is a possibility that the mounting member is depressed or the outer end of the inner cylinder is buckled.
[0007]
In order to solve this problem, it is conceivable 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 constant of the vibration isolating bush at a predetermined value, the rubber-like elastic body that performs the vibration isolating function needs to maintain the predetermined thickness. For this reason, the outer cylinder has to be increased by increasing the outer diameter of the inner cylinder, and there is a problem that the outer diameter of the entire vibration-proof bushing is increased.
[0008]
Further, when the outer diameter of the inner cylinder is increased to increase the area of the end surface of the inner cylinder, there is a problem that the weight of the inner cylinder increases, and accordingly, the weight of the entire vibration isolating bush increases.
[0009]
In view of the above problems, the present invention is a so-called bulge-type vibration-proof bushing that can reduce the surface pressure of the inner cylinder end face without changing the weight of the inner cylinder while maintaining a small size and light weight. The purpose is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a metal inner cylinder, an outer cylinder arranged at intervals on the outer side of the inner cylinder, and a rubber interposed between the inner cylinder and the outer cylinder. The inner cylinder is composed of a covering portion covered with the rubber-like elastic body, and both end portions that are located on both sides in the axial direction and are not covered with the rubber-like elastic body, A synthetic resin bulging portion bulging in a direction perpendicular to the axis is provided on the outer periphery of the covering portion, and the rubber-like elastic body is provided between the inner cylinder and the outer cylinder so as to cover the outer peripheral surface of the bulging portion. The bulged portion is formed thin at the axial center and thick at both axial sides depending on the thickness of the bulged portion, and the bulged portion is formed on the axial end surface of the rubber-like elastic body. A recess that is continuous in the circumferential direction with an axial depth reaching the axial end of the inner cylinder, and at least one of the both ends of the inner cylinder. End of the wall thickness is larger expanded diameter section than the cover portion, the vibration damping bushing, characterized in that it is formed by the enlarged diameter portion is pressed against the end face of the inner cylinder in the axial direction It is to provide.
[0011]
According to this configuration, since the enlarged diameter portion having a large thickness is formed at the end of the inner cylinder, it is not necessary to increase the outer diameter of the entire inner cylinder, so that the size and weight can be reduced. The surface pressure of the inner cylinder end surface due to fastening with the mounting member can be reduced by increasing the area.
[0012]
In addition, if the rubber-like elastic body is vulcanized between the inner and outer cylinders and then formed by pressing the end face of the inner cylinder in the axial direction, the enlarged diameter part can be easily formed by post-processing. it is Ru can.
[0013]
Further, the enlarged diameter portion can be formed not only at one end side of the inner cylinder but also at both end portions. That is, in the present invention, it is also possible to provide an anti-vibration bush in which the enlarged diameter portion is formed at both end portions of the inner cylinder.
[0014]
Moreover, the bulging part can be reduced in weight by configuring the bulging part with synthetic resin. In this case, synthetic resins such as polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, acrylonitrile-styrene resin (AS resin), ABS, acrylic resins, and other general thermoplastic resins, polyamide, polycarbonate 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 (PEEK), polyarylate, polysulfone, Polyethersulfone, Polyketone sulfide, Polyetherimide, Polytetrafluoroethylene, Aromatic polyester, Polyaminobismaleimide, Triazi Super engineering plastics called resin such as a resin can be exemplified.
[0015]
Of these, polyamides such as nylon 6 and nylon 66, polyethylene terephthalate, polybutylene terephthalate, and polyphenylene sulfide are particularly suitable. These resins may be fixed to the outer peripheral surface of the inner cylinder by injection molding or the like.
[0016]
That is, in the present invention, the bulging portion is made of a synthetic resin and can provide an anti-vibration bush fixed to the outer peripheral surface of the inner cylinder. The synthetic resin includes polyethylene terephthalate, polybutylene. An anti-vibration bush made of terephthalate, polyphenylene sulfide or polyamide can also be provided.
[0017]
As a manufacturing method of the vibration-proof bushing having the above-described configuration, in the present invention, a synthetic resin is injected onto the outer peripheral surface near the central portion in the axial direction with respect to a cylindrical inner cylinder whose inner diameter and outer diameter are constant in the axial direction. Thus, the bulging portion is fixed, an outer cylinder is disposed outside the inner cylinder to which the bulging portion is fixed, and a rubber-like elastic body is interposed between the inner cylinder and the outer cylinder. Then , the end portion of the inner cylinder is vulcanized and molded so as not to be covered with the rubber-like elastic body, and after the vulcanization molding, the one end surface in the axial direction of the inner cylinder is pressed in the axial direction by a pressure welding jig. It is possible to provide a method for manufacturing a vibration-proof bushing characterized by forming a one-side enlarged diameter portion in which the end wall thickness of the cylinder is larger than that of other portions.
[0018]
Further, in the case of forming an enlarged diameter portion at both end portions of the inner cylinder, in the present invention, after forming the enlarged diameter portion on one end portion side of the inner cylinder, the other end portion of the inner cylinder is axially moved by a pressure welding jig. It is possible to provide a method for manufacturing a vibration-proof bushing that presses and forms the other-side enlarged diameter portion in which the end wall thickness of the inner cylinder is larger than the other portions.
[0019]
According to the above configuration, as described above, after the rubber-like elastic body is vulcanized between the inner and outer cylinders, the end face of the inner cylinder is pressed in the axial direction. The enlarged diameter portion can be easily formed by post-processing. In addition, when the vibration isolating bush is removed from the mold, there is no enlarged diameter portion, so that the die cutting operation can be easily performed.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an anti-vibration bush according to an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view of an anti-vibration bush according to the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG.
[0021]
This anti-vibration bush is interposed between the inner cylinder 1 made of metal, the outer cylinder 2 arranged at an interval outward in the direction perpendicular to the axis of the inner cylinder 1, and the inner cylinder 1 and the outer cylinder 2. A ring-shaped rubber-like elastic body 3 is provided, and the inner cylinder 1 and the outer cylinder 2 are attached to different members, respectively, so that both members are connected in a vibration-proof manner.
[0022]
The inner cylinder 1 is made of, for example, steel, and has a covering portion 4 covered with the rubber-like elastic body 3 formed in the central portion in the axial direction, and a thickness on both sides in the axial direction of the covering portion 4. The enlarged diameter part 5 set larger than the coating | coated part 4 is continuously formed in the cylinder shape. Then, in the state in which the end surface 6 of the enlarged diameter portion 5 is sandwiched between mounting members such as brackets, or in the state where only the end surface 6 of one enlarged diameter portion 5 is in contact with the attachment member, the central penetration of the inner cylinder 1 is achieved. A shaft member such as a bolt is inserted into the hole and fastened and fixed to the mounting member.
[0023]
The covering portion 4 has an inner diameter and an outer diameter that are constant in the axial direction, that is, is 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 so as to increase the contact area of the end surface 6 with the mounting member. ing. As will be described later, the enlarged diameter portion 5 is formed by pressing the end surface of the inner cylinder having the same cross section in the axial direction.
[0024]
Further, the inner cylinder 1 is fixed to the outer peripheral surface of the covering portion 4 so that a bulging portion 7 made of synthetic resin bulges in a substantially spherical shape in a direction perpendicular to the axis. The bulging portion 7 can be formed of many types of synthetic resins, but is particularly preferably formed of polyamide such as nylon 6 or nylon 66, polyethylene terephthalate, polybutylene terephthalate, or polyphenylene sulfide.
[0025]
The outer cylinder 2 is, for example, a steel cylinder, and is press-fitted and fixed to the opening of the mounting member. The inner diameter and 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 is slightly smaller than the covering portion 4 of the inner cylinder 1. And is set shorter than the axial length of the inner cylinder so that the rubber-like elastic body 3 is accommodated therein.
[0026]
The rubber-like elastic body 3 is interposed between the inner cylinder 1 and the outer cylinder 2 so as to cover the outer peripheral surface of the bulging part 7 by vulcanization molding, and the thickness of the bulging part 7 outside the inner cylinder 1. Due to the above, it is set to be thin near the center in the axial direction and thick near both ends in the axial direction.
[0027]
This rubber-like elastic body 3 is thinned near the center in the axial direction to set a large spring constant in the direction perpendicular to the axis, and thickened near both ends in the axial direction to set a small spring constant in the twisting direction. It will be. The rubber-like elastic body 3 is continuous with the axial end surface in the circumferential direction as shown in FIG. 2 in order to set the axial constant, the axial perpendicular direction, and the triaxial spring constant in the twisting direction to desired values. A recess 3a is provided .
[0028]
A method of manufacturing the vibration isolating bush will be described. First, as shown in FIG. 3, an inner cylinder 1 having a constant inner diameter and an outer diameter in the axial direction, that is, a steel cylinder having the same cross-sectional shape is prepared. The inner cylinder 1 is prepared with an inner cylinder longer than the product length of the vibration-proof bushing in consideration of forming the enlarged diameter portion 5 by post-processing at both ends. The bulging portion 7 is swelled into a substantially hemispherical shape and fixed to the inner cylinder 1 by, for example, injecting heat-melted synthetic resin onto the outer peripheral surface near the center in the axial direction of the inner cylinder.
[0029]
Next, as shown in FIG. 4, the outer cylinder 2 is arranged outside the inner cylinder 1 with a space therebetween, and a rubber-like elastic body 3 is interposed between the inner and outer cylinders 1 and 2 so as to cover the bulging portion 7. The rubber-like elastic body 3 is vulcanized and molded to integrate the inner and outer cylinders 1 and 2 with the rubber-like elastic body 3.
[0030]
Next, the vulcanized molded product is taken out from the vulcanization mold, and as shown in FIG. 5, a pressure welding jig 8 is pressure-welded from the axial direction to one end portion (upper end portion in the drawing) of the inner cylinder 1. Rotate while rotating. Then, one end portion of the inner cylinder 1 is plastically deformed with axial contraction, and a conical cylindrical diameter-enlarged portion 5 having an end portion thickness larger than that of the covering portion 4 is formed.
[0031]
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 a pressure welding surface 10 is formed at the end of the jig body 9 having a circular cross section. Reference numeral 10 is a part of a conical surface, and a protrusion 11 having a circular cross section is formed at the center thereof.
[0032]
The protrusion 11 of the pressure welding jig 8 is inserted into the central hole of the inner cylinder 1 from one end of the inner cylinder 1, and the conical pressure welding surface is aligned with the one side end face 6 of the inner cylinder 1. When 8 is pivotally interlocked around the apex of the protrusion 11, the entire end surface 6 of the inner cylinder 1 is pressed against and pressed in the axial direction to be plastically deformed, and its outer diameter is increased. It should be noted that the inner diameter of the one end is not reduced because it is pressed outward by the protrusion 11, and only the outer diameter is expanded.
[0033]
After forming the enlarged diameter portion 5 at one end portion of the inner cylinder 1, the inner cylinder 1 is reversed and the enlarged diameter portion 5 is formed at the other end portion of the inner cylinder 1 in the same manner. The vibration isolating bush having the enlarged diameter portion 5 is completed.
[0034]
According to such a method for manufacturing an anti-vibration bush, after the rubber-like elastic body 3 is vulcanized and formed, the enlarged diameter portions 5 are formed at both ends of the inner cylinder 1, so that the die-cutting operation during vulcanization and molding is easy. It will be possible.
[0035]
The present invention is not limited to the embodiment described above, within the scope of the present invention, Ru can be appropriately modified.
[0036]
【The invention's effect】
As is clear from the above description, according to the present invention, in the bulge type vibration-proof bushing, since the enlarged diameter portion having a large thickness is formed at the end of the inner cylinder, it is necessary to increase the outer diameter of the entire inner cylinder. Therefore, it is possible to reduce the size and weight, improve the durability of the rubber, increase the area of the inner cylinder end surface, and reduce the surface pressure of the inner cylinder end surface by fastening with the mounting member.
[0037]
In this case, if the diameter-enlarged portion is formed by pressing the end surface of the inner cylinder in the axial direction after vulcanization molding of the rubber-like elastic body, the diameter-enlarged portion can be easily formed by post-processing. It has the advantage that it can be easily removed during vulcanization molding.
[Brief description of the drawings]
FIG. 1 is a perspective view of an anti-vibration bush according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a cross-sectional view showing a state in which a single inner cylinder is similarly cut in the axial direction.
FIG. 4 is a cross-sectional view showing a state where an anti-vibration bush before expansion of the inner cylinder is cut in the axial direction.
FIG. 5 is a cross-sectional view of an anti-vibration bush showing a state in which the outer end of the inner cylinder is similarly enlarged.
FIG. 6 is a cross-sectional view showing a state in which a conventional vibration-proof bushing is cut in the axial direction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner cylinder 2 Outer cylinder 3 Rubber-like elastic body 4 Covering part 5 Expanded part 6 End surface 7 Swelling part 8 Pressure welding jig 12 Swelling part

Claims (3)

A metal inner cylinder, an outer cylinder arranged at intervals on the outer side of the inner cylinder, and a rubber-like elastic body interposed between the inner cylinder and the outer cylinder,
The inner cylinder is composed of a covering portion covered with the rubber-like elastic body, and both end portions that are located on both sides in the axial direction and are not covered with the rubber-like elastic body ,
A synthetic resin bulging portion that bulges in the direction perpendicular to the axis is provided on the outer periphery of the covering portion,
The rubber-like elastic body is interposed between the inner cylinder and the outer cylinder so as to cover the outer peripheral surface of the bulging portion, and is thin in the axial center portion due to the thickness of the bulging portion. In addition, the rubber-like elastic body is formed with a concave portion continuous in the circumferential direction with an axial depth reaching the axial end of the bulging portion. ,
At least one end portion of the both end portions of the inner cylinder is an enlarged diameter portion having a larger thickness than the covering portion, and the enlarged diameter portion presses the end surface of the inner cylinder in the axial direction. An anti-vibration bush characterized by being formed . It is a manufacturing method of the vibration proof bush of Claim 1,
For the cylindrical inner cylinder whose inner diameter and outer diameter are constant in the axial direction, the bulging portion is fixed by injecting synthetic resin to the outer peripheral surface near the central portion in the axial direction,
Place the outer cylinder at an interval on the outside of the inner cylinder to which the bulging portion is fixed,
A rubber-like elastic body is interposed between the inner cylinder and the outer cylinder, and vulcanization molding is performed so that the end of the inner cylinder is not covered with the rubber-like elastic body,
After the vulcanization molding, one end surface of the inner cylinder in the axial direction is pressed in the axial direction with a pressure welding jig to form a one-side enlarged diameter portion where the end wall thickness of the inner cylinder is larger than the other parts. A method of manufacturing a vibration-proof bush. After forming the enlarged diameter portion on one end side of the inner cylinder, the other end surface in the axial direction of the inner cylinder is pressed in the axial direction by a pressure welding jig, and the end wall thickness of the inner cylinder becomes larger than the other portions. The manufacturing method of the vibration-proof bushing of Claim 2 which forms an other side enlarged diameter part.

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