JP2014059018A - Anti-vibration bush and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anti-vibration bush capable of improving durability while maintaining spring characteristics.SOLUTION: A rubbery elastomer is molded between an inner cylinder 12 and an outer cylinder 14, thereby, the inner cylinder and the outer cylinder are connected by a pair of elastic connection parts 16 on a position opposite to a first direction Y1 perpendicular to axis and a pair of cavity parts 24 are disposed on a second direction Y2 perpendicular to axis. Thereafter, the outer cylinder 14 is subjected to drawing compound. Therein, the drawing compound is performed such that a drawing amount on a pair of first circumferential wall parts 18 located oppositely in the first direction Y1 perpendicular to axis and a drawing amount on a pair of second circumferential wall parts 20 located oppositely in the second direction Y2 perpendicular to axis are larger than a drawing amount on a third circumferential wall part 22 interposed between the first circumferential wall parts 18 and the second circumferential wall parts 20, and a curvature R1 of the first circumferential wall part 18 and a curvature R2 of the second circumferential wall part 20 are larger than a curvature R3 of a third circumferential wall part 22, thereby, the outer cylinder 12 is formed in a substantially square cylinder shape which makes the third circumferential wall part 22 angular parts and a space for forming an extension part 16A of the elastic connection part inside the third circumferential wall part 22 is secured.

Description

  The present invention relates to an anti-vibration bush and a method for manufacturing the same.

  The anti-vibration bush is used for the purpose of vibration damping, buffering or the like at a connection portion between a vibration source such as a wheel or an engine and a vehicle body, for example. The anti-vibration bush generally includes an inner cylinder as a shaft member, an outer cylinder that surrounds the inner cylinder, and a rubber elastic body that is interposed between the inner cylinder and the outer cylinder and elastically couples the two. Conventionally, the inner and outer cylinders are cylindrical.

  In such an anti-vibration bush, in order to remove the heat shrinkage distortion of the rubber elastic body after vulcanization molding and improve durability, it is usually performed after the vulcanization molding to draw the outer cylinder in the diameter reducing direction. Is called. Therefore, conventionally, the cylindrical outer cylinder has been drawn so as to be uniformly reduced in diameter in the entire circumferential direction, thereby pre-compressing the rubber elastic body ( For example, Patent Document 1).

  On the other hand, in Patent Document 2, the curvature of the pair of second peripheral wall portions opposed to each other in the direction perpendicular to the axis orthogonal to the pair of first peripheral wall portions opposed to each other in the direction perpendicular to the axis is made smaller. A drawing method for the outer cylinder fitting is disclosed with respect to the vibration isolating bush having the outer cylinder fitting of a substantially flat cylindrical shape in which the second peripheral wall portion is a substantially flat plate shape. Thus, although Patent Document 2 discloses drawing a non-circular outer cylinder, it is intended to make the drawing amount uniform over the entire circumference of the outer cylinder, suggesting the present invention. Not what you want.

  Further, in Patent Document 3, the outer cylinder is composed of a pair of first side walls opposed in a direction perpendicular to the first axis and a pair of second side walls opposed in a direction perpendicular to the second axis perpendicular thereto. The distance between the pair of first side walls connected to the inner cylinder by the elastic connecting portion while maintaining a constant distance between the pair of second side walls that are not connected to the inner cylinder by the elastic connecting portion. It is disclosed that the outer cylinder is subjected to a drawing process in the direction of reducing the diameter of the outer cylinder. In this way, Patent Document 3 does not squeeze in one of the two orthogonal directions but squeeze in the direction perpendicular to the other axis, and therefore differs from the present invention in which the squeezing is performed in two orthogonal directions. The elastic connecting portion is provided only within the range of the first side wall, and it is not disclosed that the elastic connecting portion is provided up to a position corresponding to a corner portion of the outer cylinder having a rectangular tube shape.

JP 2005-282701 A JP 2000-104775 A JP 2009-216126 A

  FIG. 5 shows an anti-vibration bush 100 according to a comparative example. The anti-vibration bush 100 is formed by connecting an inner cylinder 101 and an outer cylinder 102 with a pair of elastic connecting portions 103 and 103 made of rubber elastic bodies at positions facing each other in the first axis-perpendicular direction Y1. In this anti-vibration bush 100, the second axis perpendicular direction Y2 perpendicular to the first axis perpendicular direction Y1 is the main load input direction, the required spring characteristics are maintained in this direction, and a predetermined stopper clearance is provided. It is required to ensure durability that can withstand use in a vehicle.

  In general, increasing the size of the anti-vibration bush is used as one method for improving the durability. However, when the size is increased, the distance between the inner and outer cylinders increases and the spring constant decreases. Therefore, with the conventional method, it has been difficult to ensure high durability while maintaining the required spring characteristics.

  An object of the present invention is to provide a vibration-proof bushing capable of improving durability while maintaining spring characteristics and a method for manufacturing the same.

  The vibration-proof bushing manufacturing method according to the present invention includes a shaft member, an outer cylinder that surrounds the shaft member in parallel with the shaft member, and an elastic connecting portion that connects the shaft member and the outer cylinder. A rubber-like elastic body formed between the outer cylinder and the shaft member so that the shaft member is sandwiched at a position facing the first axis perpendicular direction. A shaft member and the outer cylinder are connected by a pair of elastic connecting portions, and a shaft is provided between the shaft member and the outer cylinder in a second axis perpendicular direction perpendicular to the first axis perpendicular direction. A pair of hollow portions penetrating in the direction is provided, and the outer cylinder is drawn after the elastic connecting portion is formed. In the drawing process, the drawing amount at the pair of first peripheral wall portions opposed to each other in the first axis perpendicular direction and the drawing amount at the pair of second circumferential wall portions opposed to each other in the second axis perpendicular direction are obtained. The radius of curvature of the first peripheral wall portion and the radius of curvature of the second peripheral wall portion are larger than the amount of restriction in the third peripheral wall portion interposed between the first peripheral wall portion and the second peripheral wall portion, By applying so as to be larger than the curvature radius of the third peripheral wall portion, the outer cylinder is formed in a substantially rectangular tube shape with the third peripheral wall portion as a corner portion, and the elastic connecting portion is From the first peripheral wall portion to the third peripheral wall portion, the peripheral wall portion and the shaft member facing the peripheral wall portion are connected to each other.

  An anti-vibration bush according to the present invention includes: a shaft member; an outer cylinder that surrounds the shaft member in parallel to the axis; and the shaft member and the outer cylinder at positions facing each other in a first axis perpendicular direction across the shaft member. A pair of elastic connecting portions made of a rubber-like elastic body connecting between the shaft member and a shaft provided between the shaft member and the outer cylinder in a second axis perpendicular direction perpendicular to the first axis perpendicular direction A pair of hollow portions penetrating in the direction. The outer cylinder includes a pair of first peripheral wall portions opposed to each other in the first axis perpendicular direction, a pair of second peripheral wall portions opposed to each other in the second axis perpendicular direction, the first peripheral wall portion, and the A third peripheral wall portion interposed between the second peripheral wall portions, and the drawing amount after the molding of the elastic connecting portion reduces the amount of drawing in the first peripheral wall portion and the second peripheral wall portion. A radius of curvature of the first peripheral wall and the second peripheral wall is larger than a radius of curvature of the third peripheral wall, and the third peripheral wall is a corner. It is formed in a substantially rectangular tube shape. The elastic connecting portion is provided to connect the peripheral wall portion and the shaft member facing the peripheral wall portion from the first peripheral wall portion to the third peripheral wall portion, and the second peripheral wall portion. A stopper clearance in the direction perpendicular to the second axis is provided by the hollow portion between the shaft member facing the second peripheral wall portion.

  According to the present invention, the amount of restriction in the first axis perpendicular direction that affects the spring characteristics and the second axis perpendicular direction related to the stopper clearance setting are increased, and the restriction at the position corresponding to the third peripheral wall portion therebetween. By reducing the amount, it is possible to secure a large space for providing the elastic connecting portion at a position corresponding to the third peripheral wall portion. Therefore, durability can be improved, maintaining a spring characteristic by extending an elastic connection part to the position corresponded to this 3rd surrounding wall part.

It is a front view of the vibration proof bush which concerns on embodiment. It is the II-II sectional view taken on the line of FIG. It is a front view before the drawing process of the vibration isolating bush according to the embodiment. It is a figure at the time of the drawing process of the vibration proof bush which concerns on embodiment. It is a front view of the vibration proof bush concerning a comparative example. It is a displacement-distortion diagram about an anti-vibration bush of an embodiment and a comparative example.

  Hereinafter, an anti-vibration bush 10 according to an embodiment of the present invention will be described with reference to the drawings.

  For example, the vibration isolating bush 10 is provided between a vehicle body of an automobile and an engine that is a vibration generation source, and is used by being incorporated in a torque rod (not shown) that suppresses movement and vibration in the roll direction of the engine. Is.

  As shown in FIGS. 1 and 2, the anti-vibration bush 10 includes an inner cylinder 12 as a shaft member, an outer cylinder 14 surrounding the inner cylinder 12, and an vulcanized adhesive interposed between the inner cylinder 12 and the outer cylinder 14. And an elastic connecting portion 16 made of a rubber elastic body for connecting the two by means.

  The inner cylinder 12 is a cylindrical metal fitting, and in this example, the outer shape has an elongated cross-sectional track shape in a second axis-perpendicular direction Y2 to be described later.

  The outer cylinder 14 is a cylindrical metal fitting that surrounds the inner cylinder 12 in parallel with the axis, and is set to have a smaller dimension in the axial direction X than the inner cylinder 12. The outer cylinder 14 includes a pair of first peripheral wall portions 18 and 18 that are opposed to each other with the inner cylinder 12 interposed therebetween in a first axis perpendicular direction Y1 perpendicular to the axial direction X, and a perpendicular to the first axis orthogonal direction Y1. A pair of second peripheral wall portions 20, 20 facing each other across the inner cylinder 12 in the second axis-perpendicular direction Y 2, and a third peripheral wall portion 22 interposed between the first peripheral wall portion 18 and the second peripheral wall portion 20. And is formed in a substantially rectangular tube shape having a substantially rectangular cross section with the third peripheral wall portion 22 as four corner portions.

  The pair of first peripheral wall portions 18 have a substantially flat plate shape orthogonal to the first axis-perpendicular direction Y1, and are arranged substantially parallel to each other with the same interval on both sides of the inner cylinder 12 as a center. Yes. Therefore, the 1st surrounding wall part 18 comprises a pair of side wall part in the outer cylinder 14 which makes a substantially rectangular tube shape. Although the 1st surrounding wall part 18 can also be made into a perfect flat plate shape by making the curvature radius R1 infinite, in this example, from the axial center of the outer cylinder 14 to the outer peripheral surface of the 1st surrounding wall part 18 Is formed in a curved plate shape having a curvature radius R1 sufficiently larger than the distance (for example, the distance from the axial center to the outer peripheral surface of the first peripheral wall portion 18 (that is, 1/2 of A1 in FIG. 1)). = 35 mm, R1 = 100 mm). That is, the first peripheral wall portion 18 is formed in a curved plate shape that slightly bulges outward in the first axis-perpendicular direction Y1, and has an outwardly convex curvature radius R1.

  The pair of second peripheral wall portions 20 have a substantially flat plate shape orthogonal to the second axis-perpendicular direction Y2, and are arranged substantially parallel to each other with the same interval on both sides of the inner cylinder 12 as a center. ing. Therefore, the 2nd surrounding wall part 20 comprises a pair of side wall part in the outer cylinder 14 which makes a substantially rectangular tube shape. The second peripheral wall portion 20 can be made into a complete flat plate shape by setting its radius of curvature R2 to infinity, but in this example, like the first peripheral wall portion 18, the second peripheral wall portion 20 is It is formed in a curved plate shape having a radius of curvature R2 sufficiently larger than the distance to the outer peripheral surface of the two peripheral wall portions 20. That is, the second peripheral wall portion 20 is formed in a curved plate shape that slightly bulges outward in the second axis-perpendicular direction Y2, and has an outwardly convex curvature radius R2. In this example, the radii of curvature R1 and R2 are set to be the same (R1 = R2), but they may be set to different values.

  The 3rd surrounding wall part 22 is a surrounding wall part which connects the 1st surrounding wall part 18 and the 2nd surrounding wall part 20, and is formed in the curved plate shape so that both 18 and 20 may be connected gently. The third peripheral wall portion 22 has an outwardly convex curvature radius R3, and the curvature radius R3 is set sufficiently smaller than the curvature radius R1 of the first peripheral wall portion 18 and the curvature radius R2 of the second peripheral wall portion 20. (R3 <R1 and R3 <R2).

  In this example, the outer dimension A1 in the first axis perpendicular direction Y1 and the outer dimension A2 in the second axis perpendicular direction Y2 of the outer cylinder 14 are set to be the same (A1 = A2). Is formed in a substantially square cross section. Note that these outer dimensions A1 and A2 can be set to different values. In this case, the outer cylinder 14 is formed in a substantially rectangular cross section.

  The elastic connecting portion 16 is provided by connecting the inner cylinder 12 and the outer cylinder 14 at a position facing the first axis-perpendicular direction Y1. Specifically, the pair of first peripheral wall portions 18, 18 and the pair of left and right side surfaces 12A, 12A of the inner cylinder 12 facing each other in the first axis-perpendicular direction Y1 are connected to each other. It is provided in a pair of left and right positions sandwiching the inner cylinder 12 in the first axis perpendicular direction Y1. The elastic connecting portions 16 are also provided at the four corners of the outer cylinder 14 so as to connect each third peripheral wall portion 22 and the peripheral surface of the inner cylinder 12 facing this in the direction perpendicular to the axis. It has been.

  Thereby, the elastic connection part 16 is extended not only to the 1st surrounding wall part 18, but the 3rd surrounding wall part 22 of the circumferential direction both sides (in FIG. 1, the extension part of this elastic connection part 16 is 16A in FIG. In other words, from the first peripheral wall portion 18 to the third peripheral wall portions 22 and 22 on both sides in the circumferential direction, the peripheral wall portions 18 and 22 and the peripheral surface of the inner cylinder 12 facing the peripheral wall portions 18 and 22 Between the two.

  On the other hand, the elastic connection part 16 is not provided between the pair of second peripheral wall parts 20 and 20 and the inner cylinder 12 facing the second peripheral wall parts 20 in the second axis-perpendicular direction Y2. That is, the second peripheral wall portion 20 and the inner cylinder 12 facing the second peripheral wall portion 20 are not connected by a rubber elastic body, and in the second axis-perpendicular direction Y2, between the inner cylinder 12 and the second peripheral wall portion 20. Are provided with a pair of cavities 24, 24 penetrating in the axial direction X. The hollow portion 24 is provided over substantially the entire width of the second peripheral wall portion 20 in the circumferential direction of the vibration isolating bush 10.

  In the cavity portion 24, stopper portions 26, 28, and 30 made of a rubber elastic body continuous from the elastic coupling portion 16 are provided in order to limit excessive displacement of the inner cylinder 12 in the second axis perpendicular direction Y <b> 2. . Specifically, the upper cavity portion 24 in FIG. 1 is provided with a stopper portion 26 that protrudes toward the inner cylinder 12 on the inner peripheral surface of the second peripheral wall portion 20. The lower cavity portion 24 is provided with a first stopper portion 28 projecting toward the inner cylinder 12 side on the inner peripheral surface of the second peripheral wall portion 20, and on the second peripheral wall portion 20 side on the outer peripheral surface of the inner cylinder 12. A protruding second stopper portion 30 is provided. Thereby, a stopper clearance 32 in the second axis-perpendicular direction Y2 is secured by the cavity 24 between the second peripheral wall portion 20 and the inner cylinder 12 facing the second peripheral wall portion 20.

  When manufacturing the vibration isolating bushing 10 according to the embodiment, a rubber elastic body is vulcanized and molded between the inner cylinder 12 and the outer cylinder 14A, and as shown in FIG. In the opposite position, the inner cylinder 12 and the outer cylinder 14A are connected by a pair of elastic connecting portions 16, 16, and the axial direction X between the inner cylinder 12 and the outer cylinder 14A in the second axis-perpendicular direction Y2. A pair of cavities 24, 24 penetrating through are provided.

  At that time, a final product shape is used as the inner cylinder 12, but a cylindrical metal fitting having a circular cross section as shown in FIG. 3 is used for the outer cylinder 14 </ b> A. Then, by placing the inner cylinder 12 and the outer cylinder 14A in a mold (not shown) and injecting a rubber material into the cavity of the mold, the inner cylinder 12 and the outer cylinder 14A are interposed between the inner cylinder 12 and the outer cylinder 14A. The elastic connecting portion 16 and the stopper portions 26, 28, and 30 are integrally vulcanized to obtain a vulcanized molded body 34 before drawing shown in FIG.

  Next, the outer cylinder 14A of the obtained vulcanized molded body 34 is drawn. Drawing is performed so that the cylindrical outer cylinder 14A shown in FIG. 3 becomes a substantially rectangular cylinder shown in FIG. Specifically, the diaphragm amount at the pair of first peripheral wall portions 18 and 18 facing each other in the first axis perpendicular direction Y1 and the pair of second peripheral wall portions 20 facing each other in the second axis orthogonal direction Y2. , 20 are both larger than the amount of restriction at the third peripheral wall portion 22, and the curvature radius R1 of the first peripheral wall portion 18 and the curvature radius R2 of the second peripheral wall portion 20 are the third peripheral wall. Drawing is performed so that the radius of curvature R3 of the portion 22 becomes larger. Thereby, the outer cylinder 14 is formed in the substantially square cylinder shape which makes the 3rd surrounding wall part 22 a corner | angular part. The elastic connecting portion 16 is formed so as to connect between the peripheral wall portions 18 and 22 and the inner cylinder 12 from the first peripheral wall portion 18 to the third peripheral wall portion 22.

  Here, the amount of restriction is the amount of deformation in the direction of diameter reduction due to the restriction on the peripheral wall portion of the outer cylinder 14. As shown in FIG. 1, the first peripheral wall portion 18 and the second peripheral wall portion 20 are greatly deformed inward in the direction perpendicular to the axis with respect to the shape of the outer cylinder 14A before drawing shown by a two-dot chain line, The third peripheral wall portion 22 is hardly deformed. Therefore, the amount of restriction at the third peripheral wall portion 22 is smaller than the amount of restriction at the first peripheral wall portion 18 and the second peripheral wall portion 20. In this example, the aperture amount at the first peripheral wall portion 18 and the aperture amount at the second peripheral wall portion 20 are set to the same value, but may be set to different values.

  When the first peripheral wall portion 18 and the second peripheral wall portion 20 are greatly squeezed in this way, normally, the third peripheral wall portion 22 at the boundary tends to be deformed in the diameter-expanding direction. Drawing is performed so that the outer shape of the outer cylinder 14 is within the range of the outer diameter of the original outer cylinder 14A. At this time, the amount of restriction at the third peripheral wall portion 22 can be set to zero (that is, without restriction), but in order to reduce the heat shrinkage distortion of the elastic connecting portion 16A at this portion, a slight restriction is applied. It is preferable.

  Such drawing can be performed, for example, by pressing the outer peripheral surface of the outer cylinder 14 </ b> A inward in the direction perpendicular to the axis by the drawing die 40 using a drawing device having the drawing die 40 as shown in FIG. 4. The aperture die 40 includes a first aperture die 42 that abuts on the first peripheral wall portion 18, a second aperture die 44 that abuts on the second peripheral wall portion 20, and a third aperture die 46 that abuts on the third peripheral wall portion 22. Prepare. The molding surface 48 of the first drawing die 42 has a shape corresponding to the target outer peripheral surface shape of the first peripheral wall portion 18. The molding surface 50 of the second drawing die 44 has a shape corresponding to the target outer peripheral surface shape of the second peripheral wall portion 20. The molding surface 52 of the third drawing die 46 has a shape corresponding to the outer peripheral surface shape of the target third peripheral wall portion 22. Therefore, the cylindrical outer cylinder is formed by pressing the first to third diaphragm dies 42, 44, and 46 inward in the direction perpendicular to the axis and pressing the molding surfaces 48, 50, and 52 against the outer peripheral surface of the outer cylinder 14A. 14A can be drawn into the outer cylinder 14 having a substantially rectangular tube shape.

  Thereby, when the outer diameter dimension of the outer cylinder 14A before drawing shown in FIG. 3 is B, the outer dimension A1 and the second dimension Y1 of the outer cylinder 14 after drawing shown in FIG. Are both smaller than the outer dimension B (A1 <B and A2 <B).

  In addition, by performing the drawing process in the first axis perpendicular direction Y1, the elastic coupling portion 16 is pre-compressed in the first axis orthogonal direction Y1, and the heat shrinkage distortion is removed. Further, by performing drawing in the second axis perpendicular direction Y2, a predetermined stopper clearance 32 in the second axis perpendicular direction Y2 is set.

  According to the present embodiment described above, the amount of restriction in the first axis perpendicular direction Y1 that affects the spring characteristics and the second axis perpendicular direction Y2 related to the setting of the stopper clearance 32 is increased, and the third peripheral wall therebetween. A large space for providing the extended portion 16A of the elastic connecting portion 16 inside the third peripheral wall portion 22 by drawing the outer tube 14 into a rectangular tube shape with a reduced drawing amount at a position corresponding to the portion 22. Can be secured. Therefore, by extending the elastic connecting portion 16 to a position corresponding to the third peripheral wall portion 22, it is possible to improve durability while maintaining the spring characteristics.

  This point will be described in detail. FIG. 6 shows the anti-vibration bush 10 of the above embodiment and the anti-vibration bush 100 of the comparative example shown in FIG. This shows an analytical relationship between the displacement of the inner cylinders 12 and 101 when a load is input and the strain near the base of the elastic coupling portions 16 and 103 with respect to the inner cylinder. As shown in FIG. 6, in the vibration isolating bush 10 of the embodiment, the distortion of the elastic coupling parts 16 and 103 is smaller when compared with the vibration isolating bush 100 of the comparative example with the same displacement amount. Therefore, when compared as a vibration-proof bush having the same maximum stroke, the maximum distortion can be suppressed and the durability can be improved.

  The reason for such distortion reduction is considered as follows. In the anti-vibration bush 100 of the comparative example shown in FIG. 5, the free length in the vicinity of the end portion in the circumferential direction of the elastic connecting portion 103 (the dimension of the elastic connecting portion 103 indicated by C0 in the drawing) is small. Therefore, when there is an input that is displaced downward D with respect to the inner cylinder 101, a repulsive force E (force to push back) against the input acts relatively early on the outer peripheral side of the elastic coupling portion 103. As shown in FIG. 6, the distortion of the elastic connecting portion 103 rises early with respect to the displacement. On the other hand, in the vibration isolating bush 10 of the embodiment, as shown in FIG. 1, a large space is secured in this portion by reducing the amount of restriction in the third peripheral wall portion 22, so this portion A sufficient free length can be ensured in the extending portion 16A of the elastic connecting portion 16 disposed in the space (the size of the elastic connecting portion 16 indicated by C1 in the drawing is large). Therefore, it is possible to delay the timing at which the pushing-back force as described above acts on the input to the lower part D with respect to the inner cylinder 12, and to suppress an increase in distortion.

  In addition, according to the present embodiment, in the first axis-perpendicular direction Y1, since the pre-compression is applied to the elastic connecting part 16 with a sufficient amount of restriction, the third peripheral wall part is improved while improving the spring constant. Since the aperture amount is suppressed at the position corresponding to 22, the pushing-back force in the extending portion 16A can be reduced. Therefore, it is possible to improve durability by suppressing an increase in distortion while maintaining desired spring characteristics.

  Further, in the present embodiment, by extending the elastic coupling portion 16 to a position corresponding to the third peripheral wall portion 22, the extension portion is provided with respect to the anti-vibration bush 100 of the comparative example shown in FIG. 5. An increase in the spring constant based on the rubber amount of 16A is expected. Therefore, the rubber hardness for forming the elastic connecting portion 16 can be lowered accordingly, and this also leads to improvement in durability.

  Further, in the present embodiment, by performing the drawing process in the second axis perpendicular direction Y2, the stopper clearance 32 as required can be easily set in the second axis perpendicular direction Y2, which is the main input direction. Can do.

  In the present embodiment, the cylindrical outer cylinder 14A is used to form the rectangular outer cylinder 14 by drawing the cylindrical outer cylinder 14A, so that the raw material cost can be reduced and the elastic connection can be achieved. At the time of vulcanization molding of the portion 16, the cylindrical outer cylinder 14A can be set in the molding die without positioning in the circumferential direction, and the workability is excellent.

  In the present embodiment, in the drawing process, the first peripheral wall portion 18 and the second peripheral wall portion 20 are formed to have outwardly convex curvature radii R <b> 1 and R <b> 2 without forming a perfect flat plate shape. Further, buckling deformation (reverse warpage deformation toward the inner diameter side) at the first peripheral wall portion 18 and the second peripheral wall portion 20 at the time of drawing can be suppressed, and the productivity is excellent.

  In the above-described embodiment, the case where a cylindrical metal fitting is used as the outer cylinder 12A to be drawn has been described. However, the shape of the outer cylinder 12A before drawing is not limited to a cylindrical shape. Moreover, in the said embodiment, although the 1st surrounding wall part 18 and the 2nd surrounding wall part 20 were given the convex curvature outward, it is good also as a perfect flat plate shape. Furthermore, in the above-described embodiment, the inner cylinder 12 has a cross-sectional track shape, but a circular one can also be used. Moreover, in the said embodiment, although the elastic connection part 16 was extended and provided in all the four 3rd surrounding wall parts 22, for example, a pair of 3rd surrounding walls in any one side in the 2nd axis orthogonal direction Y2 The extending portion 16A may be provided in the portions 22 and 22, and the cavity portion 24 may be extended without providing the extending portion 16A in the pair of third peripheral wall portions 22 and 22 on the other side.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  The present invention can be used for various anti-vibration bushes arranged at a connection portion between various vibration sources and a support body including a vehicle such as an automobile.

DESCRIPTION OF SYMBOLS 10 ... Anti-vibration bush 12 ... Inner cylinder 14 ... Outer cylinder 16 ... Elastic connection part 18 ... 1st surrounding wall part 20 ... 2nd surrounding wall part 22 ... 3rd surrounding wall part 24 ... Hollow part 32 ... Stopper clearance X ... Axial direction Y1 ... 1st axis perpendicular direction Y2 ... 2nd axis perpendicular direction R1 ... curvature radius of the 1st peripheral wall part R2 ... curvature radius of the 2nd peripheral wall part R3 ... curvature radius of the 3rd peripheral wall part

Claims (4)

A vibration-proof bushing manufacturing method comprising: a shaft member; an outer cylinder that surrounds the shaft member in parallel with the shaft member; and an elastic connecting portion made of a rubber-like elastic body that connects the shaft member and the outer cylinder. And
By forming a rubber-like elastic body between the outer cylinder and the shaft member, a pair of gaps between the shaft member and the outer cylinder is provided at a position facing the first axis perpendicular direction across the shaft member. A pair of hollow portions penetrating in the axial direction are provided between the shaft member and the outer cylinder in a second axis perpendicular direction perpendicular to the first axis orthogonal direction, and connected by the elastic connection portion,
After forming the elastic connecting portion, the outer cylinder is subjected to a drawing process, and the drawing process includes a drawing amount at a pair of first peripheral wall portions opposed to each other in the first axis perpendicular direction and the second axis perpendicular to the second axis. The amount of restriction at the pair of second peripheral wall portions opposed to each other in the direction is larger than the amount of restriction at the third peripheral wall portion interposed between the first peripheral wall portion and the second peripheral wall portion, and the first By applying the curvature radius of the peripheral wall portion and the curvature radius of the second peripheral wall portion so as to be larger than the curvature radius of the third peripheral wall portion, the outer cylinder is abbreviated with the third peripheral wall portion as a corner portion. And forming the elastic connecting portion so as to connect between the peripheral wall portion and the shaft member facing the peripheral wall portion from the first peripheral wall portion to the third peripheral wall portion. A method for manufacturing a vibration-proof bush. The method of manufacturing a vibration-proof bushing according to claim 1, wherein a cylindrical metal fitting is used as the outer cylinder, and is formed into a square cylinder shape by the drawing after the elastic connecting portion is formed. 3. The method of manufacturing a vibration-proof bushing according to claim 1, wherein, in the drawing process, the first peripheral wall portion and the second peripheral wall portion have a shape having an outwardly convex curvature radius. A shaft member;
An outer cylinder surrounding the shaft member in parallel to the axis;
A pair of elastic connecting portions made of a rubber-like elastic body connecting the shaft member and the outer cylinder at a position facing the first axis perpendicular direction across the shaft member;
A pair of cavities penetrating in the axial direction provided between the shaft member and the outer cylinder in a second axis perpendicular direction perpendicular to the first axis orthogonal direction;
With
The outer cylinder includes a pair of first peripheral wall portions opposed to each other in the first axis perpendicular direction, a pair of second peripheral wall portions opposed to each other in the second axis perpendicular direction, the first peripheral wall portion, and the A third peripheral wall portion interposed between the second peripheral wall portions, and the drawing amount after the molding of the elastic connecting portion reduces the amount of drawing in the first peripheral wall portion and the second peripheral wall portion. A radius of curvature of the first peripheral wall and the second peripheral wall is larger than a radius of curvature of the third peripheral wall, and the third peripheral wall is a corner. Is formed in a substantially rectangular tube shape,
The elastic connecting portion is provided to connect between the peripheral wall portion and the shaft member facing the peripheral wall portion from the first peripheral wall portion to the third peripheral wall portion, and the second peripheral wall portion and the second peripheral wall portion. The anti-vibration bushing characterized in that a stopper clearance in the direction perpendicular to the second axis is provided by the hollow portion between the shaft member facing the two peripheral wall portions.

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