JP2008128412A - Vibration absorbing bush manufacturing method and vibration absorbing bush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration absorbing bush manufacturing method for allowing easy drawing work for an outer cylinder after vulcanized and molded while preventing the peeling of an adhered interface with the drawing work, and to provide a vibration absorbing bush. <P>SOLUTION: In a recessed groove forming step, a plurality of recessed grooves 24 extending to an axial direction X are formed dispersedly in an inner peripheral face 22 of the outer cylinder 20 in a peripheral direction C. So, in a drawing step, drawing work is easily applied to the outer cylinder 20 in its diameter shrinking direction even when the outer cylinder 20 is thicker. Even when great drawing work is applied to the outer cylinder 20, the deformation of formed portions of the recessed grooves 24 suppresses the distortion of a vibration absorbing base 30 on its adhesive interface to prevent the destruction of the adhesive interface and prevent the peeling thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration-proof bushing manufacturing method and a vibration-proof bush, and particularly to a vibration-proof bushing that can facilitate drawing of an outer cylinder after vulcanization and can prevent peeling of an adhesive interface accompanying drawing. The present invention relates to a method for manufacturing a bush and a vibration-proof bush.

  2. Description of the Related Art Conventionally, in an automobile suspension mechanism, an anti-vibration bush is provided at a connection portion between a vehicle body and a suspension, for example, at a connection portion between a suspension arm on a wheel side and a vehicle body side member such as a frame for the purpose of vibration damping or buffering. in use.

  In general, the vibration-isolating bushing includes an inner cylinder (first cylindrical member), an outer cylinder (second cylindrical member) disposed at an outer peripheral side of the inner cylinder, and an inner cylinder and an outer cylinder. A rubber-like elastic body (vibration-proof base) that is interposed therebetween and elastically connects the two is configured (Patent Document 1).

  In addition, as an example of the vibration isolating bush, a bulging portion that bulges in the direction perpendicular to the axis is provided in the axial center of the inner cylinder in order to increase the spring constant in the direction perpendicular to the axis and reduce the spring constant in the twisting direction A so-called bulge type vibration-proof bushing is also known (Patent Document 2).

Furthermore, in the vibration-proof bushing having the outer cylinder as described above, the outer cylinder is shrunk after vulcanization molding in order to improve the durability by removing the shrinkage of the rubber-like elastic body (vibration-proof base) after vulcanization molding. Usually, drawing is performed in the radial direction (Patent Document 3).
JP 2002-81479 A JP 2004-144150 A JP-A-11-230224

  However, the above-described vibration-proof bushing has a problem in that when the outer cylinder is drawn after vulcanization molding, the drawing of the outer cylinder is particularly difficult. Further, in the above-described vibration-proof bushing, when the outer cylinder is subjected to a large drawing process in order to sufficiently improve the durability, the distortion of the adhesion interface of the vibration-proof base increases with the plastic deformation of the outer cylinder, There was a problem that peeling occurred between the vibration-proof base and the outer cylinder.

  The present invention has been made in order to solve the above-described problems, and facilitates drawing of the outer cylinder after vulcanization molding, and can prevent peeling of the adhesive interface accompanying drawing. It aims at providing the manufacturing method of a bush, and a vibration proof bush.

  In order to achieve this object, the vibration-proof bushing manufacturing method according to claim 1 includes: a first cylindrical member; a second cylindrical member disposed at an outer peripheral side of the first cylindrical member; A method of manufacturing an anti-vibration bush including an anti-vibration base interposed between a first cylindrical member and a second cylindrical member, and a cylindrical pipe member made of a metal material Cutting a predetermined length to form the first cylindrical member and the second cylindrical member, and a plurality of grooves extending in the axial direction on the inner peripheral surface of the second cylindrical member formed by the cutting step A groove forming step for forming the groove by NC machining in a circumferential direction, and a second cylindrical member formed with a plurality of grooves by the groove forming step is coaxially arranged on the outer peripheral side of the first cylindrical member And an inner peripheral surface of the second cylindrical member and an outer peripheral surface of the first cylindrical member. Are vulcanized and bonded by vulcanization molding of a rubber-like elastic material, whereby the vibration isolating base is interposed between the first cylindrical member and the second cylindrical member, and vibration isolation is achieved by the vulcanizing step. And a drawing step of drawing the second cylindrical member having the base body vulcanized and bonded to the inner peripheral surface in the diameter reducing direction.

  According to a second aspect of the present invention, there is provided the method for manufacturing a vibration isolating bush according to the first aspect, wherein the step of forming the concave groove includes forming the plurality of concave grooves on an inner peripheral surface of the second cylindrical member. They are arranged at equal intervals in the circumferential direction.

  According to a third aspect of the present invention, there is provided the vibration isolating bushing manufacturing method according to the first or second aspect, wherein the concave groove forming step is configured such that the plurality of concave grooves are arranged at intervals wider than the groove width. It is arranged and formed.

  A method for manufacturing a vibration isolating bush according to claim 4 is the method for manufacturing a vibration isolating bush according to any one of claims 1 to 3, wherein the first step is after the cutting step and before the vulcanizing step. A bulging part forming step on the outer peripheral surface of the first cylindrical member and a bulging part forming a convex spherical surface from the outer peripheral surface of the one cylindrical member in a direction perpendicular to the axis; Prior to the vulcanization step, a concave portion that is a recess in the inner peripheral surface of the second cylindrical member and forms a concave spherical surface having a larger diameter than the bulging portion is formed on the inner peripheral surface of the second cylindrical member. A recessed portion forming step formed by processing, wherein the bulged portion forming step forms the bulged portion as a convex spherical surface centered on an axis, and the recessed portion forming step Is a trajectory obtained by rotating an arc whose center is located at a predetermined distance from the axis around the axis. The concave portion is formed as a spherical surface, and the vulcanizing step is performed in the state where the bulging portion forming the convex spherical surface is surrounded by the concave portion forming the concave spherical surface. Between the inner peripheral surface of the first cylindrical member and the outer peripheral surface of the first cylindrical member by vulcanization molding of a rubber-like elastic material, and in the drawing step, the center of the arc forming the recessed portion The diameter of the second cylindrical member is reduced by an amount corresponding to the center of the bulging portion.

  According to a fifth aspect of the present invention, there is provided a method for manufacturing a vibration-isolating bushing according to the fourth aspect, wherein the vulcanization step is performed in a virtual spherical surface defined by a concave portion as the concave spherical surface. The rubber-like elastic material is vulcanized and molded so that the vibration-proof base is connected between the first cylindrical member and the second cylindrical member.

  The vibration isolating bush according to claim 6 is manufactured by the method for manufacturing a vibration isolating bush according to any one of claims 1 to 5.

  According to the method for manufacturing an anti-vibration bush according to claim 1, in the cutting step, the cylindrical pipe material made of a metal material is cut at a predetermined length to form the first cylindrical member and the second cylindrical member. In the vulcanization step, the first cylindrical member is coaxially disposed on the outer peripheral side of the second cylindrical member, and the space between the inner peripheral surface of the first cylindrical member and the outer peripheral surface of the second cylindrical member is rubbery. The elastic material is vulcanized and bonded by vulcanization molding, and further, in the vulcanization process, the first cylindrical member is subjected to a drawing process in the diameter reducing direction, so that the first cylindrical member and the second cylindrical member are interposed. An anti-vibration bush having an anti-vibration base interposed therebetween is manufactured.

  Here, according to the vibration-proof bushing manufacturing method of the present invention, a concave groove forming step is provided at least before the vulcanization step, and in the concave groove forming step, the inner peripheral surface of the second cylindrical member is provided with a shaft. Since the plurality of concave grooves extending in the direction are formed in a state dispersed in the circumferential direction, even in the case where the thickness of the second cylindrical member is large, in the drawing step after vulcanization molding, There is an effect that the drawing process in the diameter reducing direction can be easily performed. As a result, it is possible to reduce the work cost and the apparatus cost in the drawing process, and it is possible to manufacture a vibration-proof bushing having excellent durability by sufficiently removing the shrinkage of the vibration-proof substrate after vulcanization molding.

  According to the present invention, in the groove forming step, the plurality of grooves extending in the axial direction are formed on the inner peripheral surface of the first cylindrical member in a state dispersed in the circumferential direction. Even when the second cylindrical member is subjected to a large drawing process in the drawing process in order to improve durability, distortion at the bonding interface of the anti-vibration base is suppressed by the deformation of each groove forming portion. Therefore, there is an effect that it is possible to prevent the adhesion interface from being broken and to prevent the peeling between the vibration-proof base and the second cylindrical member.

  Furthermore, according to the present invention, for the second cylindrical member formed by cutting the pipe material in the cutting step, in the concave groove forming step, a plurality of concave grooves are formed by NC processing. When forming a second cylindrical member by performing winding in a direction in which the concave groove is on the inner peripheral surface side and connecting the end portions by welding to a flat plate material in which the concave groove is formed on one surface side in advance. As compared with the above, there is an effect that it is possible to ensure the strength of the second cylindrical member itself and to avoid a decrease in dimensional accuracy associated with the winding process. As a result, in the drawing step, since the second cylindrical member can be subjected to a large drawing process, it is possible to produce a vibration-proof bushing having excellent durability by sufficiently removing the shrinkage of the vibration-proof substrate after vulcanization molding. it can.

  According to the method for manufacturing a vibration isolating bush according to claim 2, in addition to the effect exhibited by the method for manufacturing the vibration isolating bush according to claim 1, the concave groove forming step includes a plurality of concaves on the inner peripheral surface of the second cylinder. Since the grooves are formed by arranging them at equal intervals in the circumferential direction, a part of the adhesion interface of the vibration isolating substrate (that is, a part between adjacent grooves having a wide adjacent distance), It is possible to prevent the distortion associated with the drawing process from being concentrated. As a result, in the squeezing step, there is an effect that it is possible to prevent the adhesion interface from being broken and to prevent the separation between the vibration-proof base and the second cylindrical member.

  According to the method for manufacturing a vibration isolating bush according to claim 3, in addition to the effect exhibited by the method for manufacturing the vibration isolating bush according to claim 1 or 2, the concave groove forming step includes a plurality of concave grooves from the groove width. Are formed at a wide interval, so that the strength of the entire second cylindrical member is increased by the adjacent portions of the respective concave grooves while improving the ease of drawing and preventing the breakage of the adhesive interface. There is an effect that it can be secured.

  According to the method for manufacturing a vibration isolating bush according to claim 4, in addition to the effect exerted by the method for manufacturing a vibration isolating bush according to any of claims 1 to 3, A bulging portion that bulges out from the outer peripheral surface in a direction perpendicular to the axis and forms a convex spherical surface is formed on the outer peripheral surface of the first cylindrical member, and in the concave portion forming step, a depression on the inner peripheral surface of the second cylindrical member is formed. A concave portion having a concave spherical surface having a diameter larger than that of the bulging portion is formed on the inner peripheral surface of the second cylindrical member, and the bulging portion forming the convex spherical surface is formed into a concave spherical surface in the vulcanization process. Since the space between the inner peripheral surface of the second cylindrical member and the outer peripheral surface of the first cylindrical member is vulcanized and bonded by vulcanization molding of a rubber-like elastic material in a state surrounded by the installation portion, the spring constant in the twisting direction There is an effect that it is possible to manufacture a small anti-vibration bush.

  That is, in the conventional bulge-type vibration-proof bushing, the inner peripheral surface of the second cylindrical member (outer cylinder) has a straight shape. The two cylindrical members (outer cylinder) and the first cylindrical member (inner cylinder) were compressed and deformed, and the spring constant in the twisting direction could not be sufficiently reduced.

  On the other hand, according to the present invention, the concave spherical surface (concave portion) formed on the inner peripheral surface of the second cylindrical member is replaced with the convex spherical surface (bulged portion) formed on the outer peripheral surface of the first cylindrical member. Since the rubber-like elastic material (vibration-proof base) is vulcanized and molded in a surrounding state by a vulcanization process, the vibration-proof is interposed between the concave spherical surface and the convex spherical surface against displacement in the twisting direction. The base body is only subjected to shear deformation, and as a result, a vibration-proof bushing having a small spring constant in the twisting direction can be manufactured.

  In the bulging portion forming step, the bulging portion is formed as a convex spherical surface whose center is located on the axis, and in the concave portion forming step, an arc whose center is located at a predetermined distance from the axis is rotated around the axis. The concave portion is formed as a concave spherical surface formed by a trajectory rotated in the direction, and in the drawing step, the second cylindrical member is contracted by an amount in which the center of the arc forming the concave portion coincides with the center of the bulging portion. Since the diameter of the anti-vibration base is set between the concave spherical surface and the convex spherical surface, only the shear deformation can be easily performed with respect to the displacement in the twisting direction. There is an effect that it is possible to manufacture an anti-vibration bush having a smaller spring constant.

  Further, according to the present invention, since at least the recessed portion of the second cylindrical member is formed by NC processing in the recessed portion forming step, for example, the pipe material is forged in the axial direction. There is an effect that the formation cost of the recessed portion can be reduced as compared with the case where the recessed portion is formed by applying. Further, since the recessed portion can be formed with high accuracy, there is an effect that it is possible to suppress the occurrence of variation in the spring constant in the twisting direction due to variation in dimensional accuracy.

  Here, when forming a recessed part (concave spherical surface) on the inner peripheral surface of the second cylindrical member, it is necessary to increase the thickness of the second cylindrical member by the depth of the recessed part. In the drawing step, it is difficult to draw the second cylindrical member. According to the present invention, as described above, a plurality of concave grooves are formed on the inner periphery of the second cylindrical member by the concave groove forming step. Since it is formed, there is an effect that in the drawing process, the second cylindrical member can be easily drawn in the reduced diameter direction. As a result, since the depth of the recessed portion can be set deeper, a vibration isolating bush having a smaller spring constant in the twisting direction can be manufactured.

  That is, the conventional bulge type vibration-proof bushing cannot sufficiently reduce the spring constant in the twisting direction, but only forms a concave portion (concave spherical surface) on the inner peripheral surface of the second cylindrical member (outer cylinder). With this configuration, the drawing process of the second cylindrical member is impossible in the drawing process, and the recessed portion is formed by the recessed portion forming step and a plurality of recessed grooves are formed by the recessed groove forming step as in the present invention. It is possible to achieve for the first time by forming, and thereby it is possible to simultaneously reduce the spring constant in the twisting direction and facilitate the drawing process.

  According to the method for manufacturing an anti-vibration bush according to claim 5, in addition to the effect exhibited by the method for manufacturing the anti-vibration bush according to claim 4, the vulcanization step is performed in an imaginary spherical surface defined by a concave portion as a concave spherical surface. In this case, the rubber-like elastic material is vulcanized and molded so that the vibration-proof base is connected between the first cylindrical member and the second cylindrical member. The anti-vibration bush that has been squeezed into is not compressed and deformed in the axial direction of the anti-vibration base against displacement in the twisting direction. There is an effect that can be.

  According to the anti-vibration bush of Claim 6, there exists an effect similar to the anti-vibration bush manufactured by the manufacturing method of the anti-vibration bush in any one of Claim 1-5.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1A is a top view of an anti-vibration bush 100 according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the anti-vibration bush 100 taken along the line Ib-Ib in FIG. It is. FIG. 2 is a partially enlarged cross-sectional view of the vibration isolating bush 100 and corresponds to a part of the cross-sectional view shown in FIG.

  In FIG. 1, an arrow X indicates a direction parallel to the axis O (axial direction X), an arrow Y indicates a direction perpendicular to the axis O (axial perpendicular direction Y), and an arrow Z indicates a rotational direction about the position P1. (The twisting direction Z) is shown respectively.

  The anti-vibration bush 10 is a component attached to a suspension arm of an automobile. As shown in FIG. 1, the inner cylinder 10, an outer cylinder 20 arranged at an interval on the outer peripheral side of the inner cylinder 10, and these An anti-vibration base 30 is provided that is interposed between the inner cylinder 10 and the outer cylinder 20 and is made of a rubber-like elastic material.

  Here, with reference to FIG. 3, the detailed structure of the inner cylinder 10 is demonstrated. Fig.3 (a) is a top view of the inner cylinder 10, FIG.3 (b) is sectional drawing of the inner cylinder 10 in the IIIb-IIIb line | wire of Fig.3 (a). Note that the arrows X and Y in FIG. 3 are as described in FIG. The same applies to the subsequent drawings.

  The inner cylinder 10 is a member formed in a cylindrical shape having an axis O from a steel material or an aluminum alloy. As shown in FIG. 3, the inner cylinder 10 has a shaft at the center in the axial direction X (left and right direction in FIG. 3B). A bulging portion 11 that bulges around the entire circumference in the right-angle direction Y is provided. That is, the inner cylinder 10 has a symmetrical shape around the axis O.

  As shown in FIG. 3, the bulging portion 11 forms a convex spherical surface, and this convex spherical surface has a spherical surface having a center P1 on the axis O (indicated by a two-dot chain line in FIG. 3B). Are formed in the shape of a sphere that constitutes the central portion in the axial direction X of the inner cylinder 10 and are gently connected to the outer peripheral surface 12 of the cylindrical portion that constitutes both axial ends of the inner cylinder 10.

  Next, the detailed configuration of the outer cylinder 20 will be described with reference to FIG. 4A is a top view of the outer cylinder 20, and FIG. 4B is a cross-sectional view of the outer cylinder 20 taken along the line IVb-IVb in FIG. 4A. Note that an arrow C in FIG. 4 illustrates a rotation direction (circumferential direction C) about the axis O.

  The outer cylinder 20 is a member configured in a cylindrical shape having an axis O from a steel material, an aluminum alloy, or the like. As illustrated in FIG. 4, a cylindrical surface shape (straight shape) whose outer shape is constant along the axial direction X. ). In addition, the outer cylinder 20 includes a recessed portion 21 that is recessed over the entire circumference in the direction perpendicular to the axis Y at the center in the axis direction X (the left-right direction in FIG. 4B). That is, the outer cylinder 20 has a symmetrical shape around the axis O.

  As shown in FIG. 4, the recessed portion 21 forms a concave spherical surface, and this concave spherical surface is a central portion in the axial direction X of a spherical surface having a center P2 (indicated by a two-dot chain line in FIG. 4B). And is gently connected to the inner peripheral surface 22 of the cylindrical portion constituting both axial end portions of the outer cylinder 20. The outer cylinder 20 is formed with a recessed portion 21 so that the central portion in the axial direction X is thin with respect to both end portions.

  In addition, the outer cylinder 20 is a site | part to which drawing processing is given so that it may mention later. Therefore, in the state before drawing, the central portion (concave portion 21) in the axial direction X of the inner peripheral surface 22 of the outer cylinder 20 is not a strict concave spherical surface, and as shown in FIG. The concave portion 21 is a sphere whose center P2 coincides with the center P1 because the outer cylinder 20 is located in a position shifted from the axis O of the outer cylinder 20 in the direction perpendicular to the axis Y. It is formed in a band (see FIG. 1).

  That is, the central portion of the inner peripheral surface 15 of the outer cylinder 20 in the axial direction X is swelled in the above-described inner cylinder 10 by drawing the outer cylinder 20 in the diameter reducing direction, as will be described later. A portion (concave portion 21) surrounding 11 (convex spherical surface) forms a concave spherical surface that is concentric with the bulging portion 11 of the inner cylinder 10 (that is, has a common center P2). Thereby, the recessed part 21 of the outer cylinder 20 is formed in the shape which follows a certain space | interval with respect to the bulging part 11 of the inner cylinder 20 (refer FIG. 1).

  As shown in FIG. 4, a plurality of concave grooves 24 extending in the axial direction X are arranged on the inner peripheral surface 22 of the outer cylinder 20 at regular intervals in the circumferential direction C. Thereby, the outer cylinder 20 is formed thin at the circumferential position where the concave groove 24 is disposed.

  Here, in the present embodiment, a total of twelve concave grooves 24 are arranged at equal intervals of 30 ° with respect to the circumferential direction C, and the adjacent interval D between the plurality of concave grooves 24 is defined as a groove. It is set wider than the width W (specifically, about 2.5 times). The concave grooves 24 are preferably arranged at equal intervals within a range of 15 ° to 45 °, and the adjacent interval D is preferably set within a range of 2 to 3 times the groove width W.

  The concave groove 24 is formed in a shape that is recessed in a circular arc shape as a shape before drawing (see FIG. 1). Further, as described above, since the inner peripheral surface 22 of the outer cylinder 20 is provided with the concave portion 21 at the central portion in the axial direction X, the concave groove 24 is formed in the concave portion 21 as shown in FIG. It is formed over the entire other portion in the axial direction X except for. In the present embodiment, the recessed depth of the recessed groove 24 is set to be shallower (specifically, 2/3 times) than the recessed depth of the recessed portion 21.

  Returning to FIG. 1 and FIG. The vibration isolating base 30 is vulcanized and bonded between the outer peripheral surface 12 of the inner cylinder 10 and the inner peripheral surface 22 of the outer cylinder 20 by vulcanization molding of a rubber-like elastic material, whereby the bulging portion 11 of the inner cylinder 10 is obtained. Is a portion interposed between the concave portion 21 of the outer cylinder 20 and, as shown in FIG. 1 or FIG. 2, a spherical band having a substantially constant thickness in the drawn shape. It is formed in the shape of the body.

  Here, as shown in FIG. 2, the vibration isolating base 30 connects the inner cylinder 10 and the outer cylinder 20 within a virtual spherical surface 26 defined by the recessed portion 21 (concave spherical surface) of the outer cylinder 20. . That is, the antivibration base 30 is not filled between the inner cylinder 10 and the outer cylinder 20 on the axially outer side X1 of the virtual spherical surface 26. Note that, on the axially outer side X <b> 1, a rubber film 31 connected to the vibration isolation base 30 is formed on the outer peripheral surface 12 of the inner cylinder 10 and the inner peripheral surface 22 of the outer cylinder 20.

  Next, a method for manufacturing the anti-vibration bush 100 configured as described above will be described. FIG. 5 is a flowchart showing the manufacturing process of the vibration-proof bush 100.

  When manufacturing the anti-vibration bush 100, first, as shown in FIG. 5, a cutting step (S1) is performed, and a cylindrical pipe member made of a metal material is cut to a predetermined length and then cut. The inner cylinder 10 and the outer cylinder 20 are formed from the pipe materials 15 and 25 cut by the process (engraving process, S2).

  Here, the engraving step (S2) will be described with reference to FIGS. 6 and 7 are schematic views schematically illustrating the manufacturing process of the inner cylinder 10 and the outer cylinder 20, FIG. 6 (a) is a top view of the pipe material 15, and FIG. FIG. 7 is a cross-sectional view of the pipe member 15 along VIb-VIb in FIG. 7A is a top view of the pipe member 25, and FIG. 7B is a cross-sectional view of the pipe member 25 taken along VIIb-VIIb of FIG. 7A.

  When the inner cylinder 10 is manufactured, as shown in FIG. 6, NC processing is performed on the cylindrical pipe material 15 cut out in the cutting step (S1, see FIG. 5) (the engraving step S2, FIG. 5). 5), a bulging portion 11 bulging over the entire circumference in the central direction in the axial direction X (left and right direction in FIG. 6B) in the direction perpendicular to the axis Y, and the bulging portion 11 The outer peripheral surface 12 of the cylinder part which comprises the axial direction both ends of the cylinder 10 is formed (refer FIG. 3). In the engraving step (S2), a step of chamfering the axial end surface of the inner cylinder 10 is also performed.

  On the other hand, when the outer cylinder 20 is manufactured, as shown in FIG. 7, NC processing is performed on the cylindrical pipe member 25 cut out by the cutting step (S1, see FIG. 5) (cutting step S2). 5), the concave groove 24 is formed, and the concave portion 21 is formed. In other words, the engraving step (S2) when manufacturing the outer cylinder 20 includes two steps of a concave groove forming step and a concave portion forming step.

  As shown in FIG. 7, the concave groove forming step is a step of forming a plurality of concave grooves 24 on the inner peripheral surface 22 of the pipe material 25 by NC machining, whereby the inner peripheral surface 22 of the outer cylinder 20 is formed on the inner peripheral surface 22. The plurality of concave grooves 24 extending in the axial direction X are arranged at equal intervals in the circumferential direction C (see FIG. 4).

  Moreover, a recessed part formation process is a process of forming the recessed part 21 in the inner peripheral surface 22 of the pipe material 25 by NC processing, as shown in FIG. In the central portion of the axial direction X, a recessed portion 21 that is recessed over the entire circumference in the direction perpendicular to the axial direction Y is formed (see FIG. 4).

  Note that, as described above, the outer cylinder 20 has a central portion in the axial direction X on the inner peripheral surface 22 of the outer cylinder 20 (the recessed portion 21 indicated by a two-dot chain line in FIG. 7B) before drawing. Is not a strict concave spherical surface, and the center P2 is at a position shifted in the axis-perpendicular direction Y from the axis O of the outer cylinder 20, as shown in FIG.

  That is, the NC machining in the recessed portion forming step is performed by using the arc (the two-dot chain line in FIG. 7 (b)) where the center P2 is displaced from the axis O as shown in FIG. 7 (b). This is a process of cutting the inner peripheral surface 22 of the pipe material 25 by a locus when rotated around the axis O in a state where the distance between the center P2 and the axis O is maintained.

  Then, in the drawing step (S4) to be described later, the outer cylinder 20 is drawn in the diameter reducing direction so that the recessed portion 21 is formed into a spherical band whose center P2 coincides with the center P1 (FIG. 1). reference). In the engraving step (S2), the chamfering of the axial end surface of the outer cylinder 20 is performed together with the concave groove forming step and the concave portion forming step (see FIG. 4).

  Returning to FIG. As shown in FIG. 5, after the inner cylinder 10 and the outer cylinder 20 are manufactured by the engraving process (S2), the process proceeds to the vulcanization process (S3). Here, the vulcanization step (S3) will be described with reference to FIG. FIG. 8 is a cross-sectional view of the vulcanized molded body before drawing.

  In the vulcanization step (S3), the inner cylinder 10 and the outer cylinder 20 manufactured by the above-described engraving step (S2) are placed in a vulcanization mold (not shown), and rubber-like elasticity is introduced into the vulcanization mold. By injecting a material and vulcanizing and bonding the outer peripheral surface 12 of the inner cylinder 10 and the inner peripheral surface 22 of the outer cylinder 20 by vulcanization molding of a rubber-like elastic material, the inner cylinder 10 and the outer cylinder 20 An anti-vibration substrate 30 is interposed therebetween. As a result, the vulcanized molded body (anti-vibration bush 100) before drawing shown in FIG. 8 is obtained.

  Returning to FIG. As shown in FIG. 5, after the vulcanized molded body is manufactured by the vulcanization step (S3), the process proceeds to the drawing step (S4). Here, with reference to FIG. 9, the drawing step (S4) will be described. FIG. 9 is a cross-sectional view of the drawing die 52 and the vulcanized molded body, and is a view for explaining the drawing step (S4).

  The drawing step (S4) is a step of drawing the outer cylinder 20 of the vulcanized molded body formed in the vulcanizing step (S3) in the direction of diameter reduction, and is divided radially as shown in FIG. This is done using a die 52 having a plurality of die pieces 50.

  In the present embodiment, as shown in FIG. 9, the dice 52 is divided into twelve grooves of the same number as the concave grooves 24 of the outer cylinder 20, and the concave grooves 24 are located at the center in the circumferential direction of each die piece 50. Thus, the vulcanized molded body is installed, and each die piece 50 is moved toward the radially inner side (vulcanized molded body side), whereby the outer cylinder 20 is drawn in the reduced diameter direction.

  Thereby, the anti-vibration bush 100 is manufactured (refer FIG. 1 or FIG. 2). The concave groove 24 is not completely crushed after the drawing process, and remains in a state in which the anti-vibration base 30 (rubber-like elastic material) is filled in the concave groove 24.

  Next, with reference to FIG. 10, the assembled state of the vibration isolating bush 100 to the vehicle will be described. FIG. 10 is a cross-sectional view showing a state where the vibration isolating bush 100 is assembled to the vehicle.

  As shown in FIG. 10, the inner cylinder 10 of the vibration isolating bush 100 is fixed to the bracket 1 by tightening with a fastening member (not shown) such as a bolt in a state where both end faces are sandwiched between the brackets 1 on the vehicle body side. At the same time, the outer cylinder 20 is press-fitted and fixed to the cylindrical holder 3 of the suspension arm 2, whereby the anti-vibration bush 100 connects the suspension arm 2 and the bracket 1 on the vehicle body in an anti-vibration manner.

  According to the vibration isolating bush 100 configured as described above, the concave spherical surface (concave portion 21) concentric with the convex spherical surface of the bulging portion 11 of the inner cylinder 10 is formed on the inner peripheral surface 22 of the outer cylinder 20. By providing (see FIG. 1), most of the force received by the anti-vibration base 30 interposed between the bulging portion 11 and the recessed portion 21 is sheared when displaced in the twisting direction Z. Therefore, the spring constant in the twisting direction Z can be effectively reduced.

  On the other hand, in the axial direction X, the vibration isolating base 30 is subjected not only to shear deformation but also to compression deformation between the bulging portion 11 and the recessed portion 21 (see FIG. 2), so that the spring constant increases. Can be achieved.

  Therefore, as shown in FIG. 10, when the vibration isolating bush 100 is attached to the suspension arm 2, the spring constant in the axial direction X is improved while reducing the spring constant in the twisting direction Z and improving riding comfort. By increasing the constant, it is possible to improve the handling stability, and as a result, it is possible to achieve both riding comfort and handling stability.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  The numerical values (for example, the number, size, angle, etc. of each component) given in the above embodiment are examples, and other numerical values can naturally be adopted.

  In the above-described embodiment, the case where the bulging portion 11 provided in the inner cylinder 10 is configured integrally with the cylinder portion from a metal material has been described. However, the present invention is not necessarily limited to this. For example, a resin is provided on the outer peripheral surface of the cylinder portion. You may make it comprise the bulging part 11 by attaching the cyclic | annular covering body which consists of material.

(A) is a top view of the anti-vibration bush in one embodiment of the present invention, (b) is a cross-sectional view of the anti-vibration bush along the Ib-Ib line in FIG. 1 (a). It is a partial expanded sectional view of a vibration proof bush. (A) is a top view of an inner cylinder, (b) is sectional drawing of the inner cylinder in the IIIb-IIIb line | wire of Fig.3 (a). (A) is a top view of an outer cylinder, (b) is sectional drawing of the outer cylinder in the IVb-IVb line | wire of Fig.4 (a). It is a flowchart which shows the manufacturing process of an anti-vibration bush. (A) is a top view of a pipe material, (b) is sectional drawing of the pipe material in VIb-VIb of Fig.6 (a). (A) is a top view of a pipe material, (b) is sectional drawing of the pipe material in VIIb-VIIb of Fig.7 (a). It is sectional drawing of the vulcanization molded object before a drawing process. It is sectional drawing of a drawing die and a vulcanization molding. It is sectional drawing which shows the assembly | attachment state to the vehicle of a vibration proof bush.

Explanation of symbols

100 Anti-vibration bush 10 Inner cylinder (first cylindrical member)
11 bulging portion 12 outer peripheral surface 15 pipe material 20 outer cylinder (second cylindrical member)
21 concave portion 22 inner peripheral surface 24 concave groove 25 pipe material 26 virtual spherical surface 30 anti-vibration base S1 cutting step S3 vulcanization step S4 drawing step X axial direction Z twisting direction C circumferential direction O axis W groove width D adjacent interval (concave) Groove spacing)
P1 center (center of convex spherical surface)
P2 center (center of concave spherical surface)

Claims (6)

A first cylindrical member, a second cylindrical member disposed on the outer peripheral side of the first cylindrical member with a space therebetween, and a rubber-like elastic material interposed between the first cylindrical member and the second cylindrical member. In the manufacturing method of the vibration isolating bush provided with the anti-vibration base,
A cutting step of cutting a cylindrical pipe member made of a metal material with a predetermined length to form the first cylindrical member and the second cylindrical member;
A groove forming step of forming a plurality of grooves extending in the axial direction on the inner peripheral surface of the second cylindrical member formed by the cutting step and forming the groove by NC machining;
A second cylindrical member having a plurality of concave grooves formed by the concave groove forming step is arranged coaxially on the outer peripheral side of the first cylindrical member, and the inner peripheral surface of the second cylindrical member and the first cylindrical member A vulcanization step of interposing the vibration-proof base between the first cylindrical member and the second cylindrical member by vulcanizing and bonding between the outer peripheral surface by vulcanization molding of a rubber-like elastic material;
And a drawing step of drawing the second cylindrical member, in which the vibration-proof base is vulcanized and bonded to the inner peripheral surface by the vulcanization step, in the diameter reducing direction. .   2. The anti-vibration method according to claim 1, wherein the concave groove forming step forms the plurality of concave grooves at equal intervals in the circumferential direction on the inner peripheral surface of the second cylindrical member. Bush manufacturing method.   3. The method for manufacturing a vibration-proof bushing according to claim 1, wherein in the step of forming the concave groove, the plurality of concave grooves are formed with an interval wider than the groove width. After the cutting step and before the vulcanization step, a bulging portion that bulges from the outer peripheral surface of the first cylindrical member in the direction perpendicular to the axis and forms a convex spherical surface is provided on the outer peripheral surface of the first cylindrical member. A bulging part forming step to be formed on,
After the cutting step and before the vulcanization step, a concave portion that is a recess in the inner peripheral surface of the second cylindrical member and has a concave spherical surface that is larger in diameter than the bulging portion is provided in the second portion. A recessed portion forming step formed by NC processing on the inner peripheral surface of the cylindrical member,
The bulging portion forming step is to form the bulging portion as a convex spherical surface whose center is located on the axis,
The concave portion forming step is to form the concave portion as a concave spherical surface formed by a trajectory obtained by rotating an arc whose center is located apart from the axis by a predetermined interval around the axis,
In the vulcanization step, the bulging portion forming the convex spherical surface is surrounded by the concave portion forming the concave spherical surface, and the inner peripheral surface of the second cylindrical member and the outer peripheral surface of the first cylindrical member are Is vulcanized and bonded by vulcanization molding of rubber-like elastic material,
4. The squeezing step is to reduce the diameter of the second cylindrical member by an amount in which the center of the arc forming the recessed portion coincides with the center of the bulging portion. A method for producing a vibration-proof bush according to any one of the above.   In the vulcanization step, the rubber-like elasticity is formed so that the vibration-proof base is connected between the first cylindrical member and the second cylindrical member within a virtual spherical surface defined by the concave portion as the concave spherical surface. The method for manufacturing a vibration-proof bushing according to claim 4, wherein the material is vulcanized.   An anti-vibration bush produced by the method for producing an anti-vibration bush according to claim 1.

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