JP2006026746A - Method for producing vibration-proof bush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a vibration-proof bush by which, when enlarging the end part of an inner cylinder in the diameter by cold plastic working after forming a rubber elastic body through vulcanization, the area of the end face in the inner cylinder can be secured larger than before. <P>SOLUTION: When the end part 18a in the axial direction of the inner cylinder 12 is enlarged in the diameter by the cold plastic working after fixing the rubber elastic body 16 to the outer periphery of the inner cylinder 12 by vulcanization forming, as a diameter-enlarging tool 30 for pressing against the end face 20a of the inner cylinder 12, the tool having almost flat part on the distal end face 32 is used. The distal end face 32 of the diameter-enlarging tool 32 is pressed against the end face 20a of the inner cylinder 12 while being revolved on a conical route by using the axis x0 of the inner cylinder 12 as the center and thus, the diameter only at the outer diameter side is enlarged while restraining the enlargement of the diameter at the inner diameter side of the end part 18a of the inner cylinder. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing an anti-vibration bush that is mainly used by being incorporated in an automobile suspension mechanism or the like.

  In the suspension mechanism of an automobile, a cylindrical protection is provided at a connection portion between the vehicle body and the suspension, that is, at a connection portion between an arm supporting the wheel (such as a lower arm) and a vehicle body side member such as a frame for the purpose of vibration damping and buffering. A vibration bush is used. In addition, a cylindrical vibration-proof bush may be used for an engine mount that supports the engine in a vibration-proof manner.

  FIG. 8 shows a conventional anti-vibration bush 100. The bush 100 has a metallic inner cylinder 101 and an outer cylinder 102 arranged concentrically, and rubber elasticity interposed therebetween. It consists of a body 103. In use, the anti-vibration bush 100 is fastened and fixed to a support member 105 such as a bracket having the shaft member 104 inserted through the inner tube 101 and sandwiching the inner tube 101 from both ends. The outer cylinder 102 is press-fitted and fixed to the mounting hole 107 of the other support member 106.

  Thus, since both ends of the inner cylinder 101 of the vibration isolating bush 100 are sandwiched between the support members 105, if the area of the end face 108 of the inner cylinder 101 is small, the surface pressure of the end face that receives the axial force due to fastening increases. The support member 105 such as a bracket press-molded from the plate body is depressed, thereby causing problems such as bolt loosening.

  Therefore, in order to keep the surface pressure against the axial force due to fastening at the end face below a certain level, the thickness of the straight inner cylinder 101 is increased overall, and the end face 108 serving as the contact surface with the support member 105 is increased. A technique to enlarge the area is taken. However, when the thick inner cylinder 101 is used, although the area of the end surface 108 of the inner cylinder 101 that receives the axial force is increased, there is a problem that the weight is significantly increased.

  In addition, as shown in FIG. 9, there is also a method of expanding the area of the end surface 108 that is a contact surface with the support member 105 by using a deformed inner cylinder 101 in which both end portions 109 are formed thicker than the inner portion. . However, in this case, since the inner cylinder 101 has an irregular shape, a preformed one by a processing method such as forging is used, which leads to an increase in cost. Further, when the rubber elastic body 103 is vulcanized and molded, there is a problem that the end length 110 of the rubber elastic body 103 cannot be sufficiently secured due to the relationship of die cutting after molding, and the durability deteriorates. is there. That is, when the end portion 109 of the inner cylinder 101 is previously enlarged in diameter, when the rubber elastic body 103 is vulcanized, the small diameter portion 111 inside the enlarged end portion 109 has an axial direction. Since it has an undercut shape with respect to die cutting, the end surface 110 of the rubber elastic body 103 cannot be set at the position of the two-dot chain line 112 because of die cutting after vulcanization molding. Therefore, the area of the end surface 110 of the rubber elastic body 103 is small, and a sufficient free length for elastic deformation cannot be secured.

  Incidentally, in Japanese Patent Laid-Open No. 5-200438, as shown in FIG. 10, the end portion 109 of the inner cylinder 101 is formed by cold plastic working using a diameter expansion jig 120 after vulcanization molding of the rubber elastic body 103. It is disclosed that the end face 108 is expanded by expanding the diameter. In this publication, as the diameter expansion jig 120, a tool having a protrusion 121 at the center of the tip surface is used, and the diameter expansion jig 120 is swung on a conical orbit about the shaft 122 of the inner cylinder 101. It is pressed against the inner cylinder end surface 108 while moving, thereby expanding the end surface 108 as shown in FIG. According to this method, the area of the end surface 108 of the inner cylinder 101 can be increased without using a thick tube, and the area of the end surface 110 of the rubber elastic body 103 can be increased to increase the free length against elastic deformation. It can be secured sufficiently.

However, in the diameter expansion method disclosed in the publication, the end 109 of the inner cylinder 101 is expanded not only in the outer diameter D0 but also in the inner diameter d0 as shown in FIG. Accordingly, the area of the inner cylinder end surface 108 is narrowed, and accordingly, it is difficult to ensure a sufficient area for reducing the surface pressure against the axial force.
Japanese Patent Laid-Open No. 5-200438

  The present invention has been made in view of the above points. When the end of the inner cylinder is expanded by cold plastic working after vulcanization molding of the rubber elastic body, the inner cylinder It aims at providing the manufacturing method of the vibration proof bush which can ensure the area of an end surface large.

  The vibration-proof bushing manufacturing method of the present invention is a vibration-proof bushing manufacturing method in which a rubber elastic body is fixed to the outer periphery of an inner cylinder by vulcanization molding, and after the rubber elastic body is vulcanized and molded, When expanding the diameter of the axial end of the cylinder by cold plastic working, as a diameter expansion jig pressed against the end face of the inner cylinder, a jig whose tip surface is substantially flat is used. The tip surface is pressed against the end surface of the inner cylinder while rotating on a conical orbit about the axis of the inner cylinder, thereby extending the end surface of the inner cylinder.

  In this way, by using a flat diameter expansion jig having no protrusion on the tip surface, the diameter of the inner cylinder end is increased by the pressure swivel movement of the diameter expansion jig. Therefore, only the outer diameter side can be expanded, and therefore the area of the end surface of the inner cylinder can be sufficiently secured.

  In the manufacturing method of the present invention, the diameter increasing jig is formed in a conical surface shape in which the tip surface of the diameter expanding jig slightly protrudes, and the diameter increasing jig is substantially parallel to the end surface of the inner cylinder. You may incline with respect to the axis | shaft of the said inner cylinder. This method is effective when only the outer diameter is expanded and the inner diameter is hardly changed.

  In the manufacturing method of the present invention, a constraining wall surrounding the outer periphery of the end of the inner cylinder to be expanded is provided on the peripheral edge of the tip surface of the diameter expansion jig. You may restrict | limit that an edge part is diameter-expanded more than predetermined. This method is effective when the outer diameter is increased and the inner diameter is reduced, so that the area of the end surface of the inner cylinder can be further increased.

  As described above, according to the vibration-proof bushing manufacturing method of the present invention, the wall thickness of the inner cylinder is increased by expanding the end of the inner cylinder by plastic working after vulcanization molding of the rubber elastic body. The area of the end face can be increased. In particular, by performing a diameter expansion using a flat diameter expansion jig that does not have a protrusion on the tip surface, it is possible to suppress the diameter expansion on the inner diameter side of the inner cylinder end, and to expand only the outer diameter side, Accordingly, a sufficient area of the end surface of the inner cylinder can be ensured. In addition, the free length of the rubber elastic body can be sufficiently secured, and the rubber elastic body can be manufactured at a low weight and at a low cost.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 is a cross-sectional view of the vibration isolating bushing 10 according to the first embodiment of the present invention at the time of diameter expansion processing, FIG. 2 is a side view of a diameter expansion jig 30 used for the diameter expansion processing, and FIG. It is sectional drawing of the vibration isolating bush 10 obtained by processing.

  The anti-vibration bush 10 of the present embodiment includes an inner cylinder 12 and an outer cylinder 14 made of metal pipes such as iron, steel, aluminum, or alloys thereof arranged concentrically, and both the inner and outer cylinders 12, 14 is composed of a rubber elastic body 16 that is interposed by vulcanization molding and integrally couples the two cylinders. The rubber elastic body 16 is formed on both the outer peripheral surface of the inner cylinder 12 and the inner peripheral surface of the outer cylinder 14. It is fixed by vulcanization adhesion means. As shown in FIG. 3, the inner cylinder 12 is slightly longer than the outer cylinder 14 and the rubber elastic body 16, both end portions 18 a and 18 b are expanded, and the end surfaces 20 a and 20 b are end surfaces with normal thickness. Compared to the case, it is expanded.

  When manufacturing the vibration isolating bushing 10, first, a rubber elastic body 16 is vulcanized between the inner cylinder 12 and the outer cylinder 14 in a vulcanization mold (not shown). At that time, as shown in FIG. 1, the inner cylinder 12 is a straight pipe in which both end portions 18a and 18b are not diameter-expanded, and the tube is cut slightly longer in consideration of the diameter-expansion processing of the end portions. An inner cylinder 12 is used.

  Next, the diameter of the end portion in the axial direction of the inner cylinder 12 is expanded by plastic working that gives a plastic deformation in the cold. That is, as shown in FIG. 1, as the processing jig pressed against the end surfaces 20a, 20b of the inner cylinder 12, a diameter expanding jig 30 having a substantially flat tip surface 32 is used. The tip end face 32 is pressed against the end faces 20a and 20b of the inner cylinder 12 while turning on a conical orbit about the axis 12 of the twelve, thereby expanding the end face of the inner cylinder 12.

  As shown in FIG. 2, the diameter expansion jig 30 includes a cylindrical portion 34 having a large diameter that is pressed against the inner cylinder 12 on the lower end side, and an attachment portion 36 on the upper end is attached to a rotating device (not shown). ing. And the front end surface 32 of the diameter-expansion jig | tool 30 which is the lower surface of the cylindrical part 34 is formed in the substantially flat conical surface shape protruded slightly toward the downward direction, ie, the press direction front. The inclination angle α of the conical surface (tip surface) 32 is normally set to 0 to 10 °. The diameter of the cylindrical portion 34 is set sufficiently larger than the outer diameter of the inner cylinder 12 as shown in FIG.

  The diameter expansion jig 30 is attached to the rotating device so that its axis x1 has a fixed angle β with respect to the axis x0 of the inner cylinder 12, and the shaft x1 is moved by the operation of the rotating device. The end surfaces 20a and 20b of the inner cylinder 12 are pressed while turning so as to move on a conical surface centering on the axis x0 of the inner cylinder 12. The angle β is set so that the conical end surface 32 of the diameter expanding jig 30 is substantially parallel to the end surfaces 20a, 20b of the inner cylinder 12, and therefore, the inclination angle α of the end surface 32 is substantially the same. Set the same.

  In the diameter expansion process of the inner cylinder 12 by the diameter expansion jig 30, first, one end portion, for example, the end portion 18a on the side that is more plastically deformed is expanded in diameter as described above. The sulfur molded body is turned upside down, and the other end portion, for example, the end portion 18b on the side to be plastically deformed smaller is processed in the same manner to expand the diameter.

  Thereby, it can process into a shape like FIG. That is, in the diameter expansion method of this embodiment, since the flat diameter expansion jig 30 having no central protrusion is used on the tip surface 32, the diameter expansion on the inner diameter side of the inner cylinder end 18 can be suppressed, Therefore, only the outer diameter D can be expanded, and the inner diameter d can be kept unchanged with the inner diameter of the original tube almost unchanged.

  The anti-vibration bush 10 thus obtained is fixed by press-fitting the outer cylinder 14 into a mounting hole 42 of a support member 40 such as an arm of a suspension, as shown in FIG. 12, the other support-side shaft member 44 is passed through and fastened and fixed in a state of being sandwiched from both sides by a support member 46 such as a bracket.

  According to the first embodiment described above, since the end portions 18a and 18b of the inner cylinder 12 are subjected to diameter expansion processing and the end surfaces 20a and 20b are expanded, the thickness of the inner cylinder 12 does not have to be increased. However, it is possible to secure an area where the surface pressure against the axial force due to the fastening with the support member 46 can be reduced, and it is lightweight and inexpensive. In particular, since a flat jig having no protrusion on the tip surface 32 is used as the diameter expanding jig 30, only the outer diameter D can be expanded and the inner diameter d can be hardly changed. The area of the end face 20 of the inner cylinder 12 can be secured sufficiently large.

  Further, since the end portions 18a and 18b of the inner cylinder 12 are subjected to diameter expansion processing after the vulcanization molding of the rubber elastic body 16, the shape of the end surface portion 22 of the rubber elastic body 16 can be arbitrarily set such as a curved surface shape. . For example, as shown in FIG. 3, the both end surfaces 22 of the rubber elastic body 16 can be provided with a recess that is depressed in the axial direction. Thus, since the area of the end surface 22 of the rubber elastic body 16 can be ensured large, the free length with respect to elastic deformation can be sufficiently ensured and the durability of the rubber elastic body 16 can be improved.

  4 is a cross-sectional view of the vibration isolating bushing 10 according to the second embodiment of the present invention during the diameter expansion process, FIG. 5 is a side view of the diameter expansion jig 30 used for the diameter expansion process, and FIG. FIG. 7 is a cross-sectional view of the vibration isolating bush 10 obtained by processing, and FIG. 7 is an enlarged cross-sectional view of the main part at the end of the diameter expansion processing.

  The second embodiment is different from the first embodiment in the shape of the diameter expanding jig 30 for processing the end portion of the inner cylinder 12. That is, in the present embodiment, the substantially flat conical tip end surface 32 of the diameter expanding jig 30 has a constraining wall 38 surrounding the outer periphery of the inner cylinder end portions 18a and 18b to be expanded in diameter at the peripheral edge thereof. The inner wall end portions 18a and 18b are restricted from being expanded by a predetermined diameter or more by the restraining wall 38.

  As shown in FIG. 5, the constraining wall 38 is formed so as to protrude downward from the periphery of the tip end surface 32 of the cylindrical portion 34 of the diameter expanding jig 30, that is, forward in the pressing direction, and the inside thereof is substantially flat as described above. It is formed in a conical surface shape. The inner peripheral wall surface of the constraining wall 38 is inclined outward by a predetermined angle γ with respect to the axial direction of the diameter expansion jig 30, and this angle γ is the inner cylinder end surface 20 when the wall surface is expanded. Is set to be substantially the same as the inclination angle α of the tip end face 32. Further, the width W of the substantially flat surface in the shape of a conical surface existing inside the constraining wall 38 is appropriately set according to the desired external dimension D of the inner cylinder end portion 18 whose diameter is increased.

  When this diameter expansion jig 30 is used to perform a diameter expansion process similar to the above as shown in FIG. 4, the outer periphery of the end 18a of the inner cylinder 12 is expanded to the restraint wall 38 as shown in FIG. When it is done, it cannot spread to the outer diameter side any more, so it plastically deforms to the inner diameter side accordingly. As a result, as shown in FIG. 6, the outer diameter D of the inner cylinder 12 end 18 can be increased and the inner diameter d can be reduced, and the area of the end surface 20 of the inner cylinder 12 can be further increased. Can do.

  In the above embodiment, the diameter expansion processing is applied to both end portions 18a and 18b of the inner cylinder 12, but the present invention is not limited to this, and only one end portion is expanded in diameter. Also good. In the above embodiment, the rubber elastic body 16 is interposed between the inner cylinder 12 and the outer cylinder 14 press-fitted into the mounting hole 42 of the support member 40, and is fixed to both the cylinders. In this case, the rubber elastic body 16 is fixed only to the outer periphery of the inner cylinder 12 by vulcanization molding, and is rubbery with respect to the mounting hole of the other support member. Also in the vibration isolating bush of the type in which the elastic body 16 is pressed and used, the end portion 18 of the inner cylinder 12 can be configured and implemented in the same manner as described above.

It is sectional drawing at the time of the diameter expansion process of the vibration isolating bush which concerns on the 1st Embodiment of this invention. It is a side view of the diameter expansion jig used for the diameter expansion process. It is a longitudinal cross-sectional view of the anti-vibration bush obtained by the diameter expansion process. It is sectional drawing at the time of the diameter-expansion process of the vibration isolating bush which concerns on 2nd Embodiment. It is a side view of the diameter expansion jig used for the diameter expansion process. It is a longitudinal cross-sectional view of the anti-vibration bush obtained by the diameter expansion process. It is a principal part expanded sectional view at the time of completion | finish of the diameter expansion process. It is a longitudinal cross-sectional view which shows an example of the conventional anti-vibration bush. It is a longitudinal cross-sectional view which shows the other example of the conventional anti-vibration bush. It is sectional drawing at the time of the diameter expansion process of the conventional anti-vibration bush. It is a longitudinal cross-sectional view of the anti-vibration bush obtained by the diameter expansion process of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Anti-vibration bush 12 ... Inner cylinder 14 ... Outer cylinder 16 ... Rubber elastic body 18a, 18b ... End part 20a, 20b ... End surface 30 ... Diameter-expansion jig 32 ... End surface 38 ... Restraint wall

Claims (3)

A method of manufacturing a vibration isolating bush formed by fixing a rubber elastic body to the outer periphery of an inner cylinder by vulcanization molding,
After vulcanization molding of the rubber elastic body, when expanding the axial end of the inner cylinder by cold plastic working,
As a diameter expansion jig pressed against the end surface of the inner cylinder, a jig whose tip surface is substantially flat is used.
The tip expansion surface is pressed against the end surface of the inner cylinder while the diameter expanding jig is swung on a conical orbit about the axis of the inner cylinder, thereby expanding the end surface of the inner cylinder. A method for manufacturing a vibration-proof bush. The tip surface of the diameter expansion jig has a conical surface shape slightly protruding,
The method for manufacturing a vibration-proof bushing according to claim 1, wherein the diameter increasing jig is inclined with respect to the axis of the inner cylinder so that the conical surface is substantially parallel to an end surface of the inner cylinder. A constraining wall that surrounds the outer periphery of the end of the inner cylinder to be expanded is provided on the peripheral edge of the tip surface of the diameter expansion jig, and the inner cylinder end is enlarged by a predetermined amount or more by the constraining wall. The method of manufacturing a vibration-proof bushing according to claim 1 or 2, wherein:

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