JP2016017523A - Bushing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bushing capable of restricting an axial displacement while assuring a characteristic of a vibration isolator and improving durability.SOLUTION: A bored section 41 formed at each of axial end surfaces of a vibration isolator 40 can assure soft spring characteristics in both radial direction and an axial direction because each of bottom portions 44 is positioned at axial inside part than from each of starting points 32 at two bent portions 31 or on each of the starting points 32 at a section including an axial center O. A protrusion part 22 protruded toward an outer cylinder 30 has Young's modulus in its axial direction is set to be higher than a Young's modulus in an axial direction of the vibration isolator 40. The protrusion part 22 can restrict an excessive displacement in an axial direction of the vibration isolator 40 by the protrusion part 22 and the bent portions 31 at a section including the axial center O to improve durability because the protrusion part 22 is arranged at axial inside of the two bent portions 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bush, and more particularly to a bush that can achieve both the characteristics and durability of a vibration-proof base.

  In an automobile suspension device or the like, a bush is disposed between a vehicle body and a vibration-side member (Patent Document 1). In the bush disclosed in Patent Document 1, an annular curl is formed on the axial end surface of the vibration isolating base, and the outer cylinder connected to the inner cylinder by the vibration isolating base has both axial ends inward in the radial direction. It has two bent parts that bend. In this bush, the spring constant in the radial direction of the vibration-proof base can be reduced by the improvement. Further, since the bending portion can restrict an excessive displacement of the vibration isolating base when a large radial vibration is input, durability of the vibration isolating base can be ensured.

JP 2002-161943 A

  However, the above-described conventional technique has a problem that it is not possible to regulate an excessive displacement of the vibration-proof base when a large axial vibration is input.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a bushing that can improve durability by restricting axial displacement while ensuring the characteristics of the vibration-proof base.

Means for Solving the Problems and Effects of the Invention

  In order to achieve this object, according to the bush of the first aspect, the outer cylinder is coaxially arranged at a distance on the outer side in the radial direction of the inner cylinder, and is externally provided by a vibration-isolating base composed of a rubber-like elastic body. The cylinder and the inner cylinder are integrally connected. The outer cylinder includes two bent portions whose both ends in the axial direction are bent inward in the radial direction, and the antivibration base is formed with an annular curl that makes one round in the circumferential direction on the axial end surface. In the cross section including the axial center, since the bottom portion is located inside the axial direction of the two bent portions or at the axial position of the respective starting points, the radial direction and the axial direction of the vibration-proof base are soft. Spring characteristics can be secured.

  In the inner cylinder, a protrusion provided on the outer periphery protrudes toward the outer cylinder, and the protrusion has an axial Young's modulus set to a value larger than the axial Young's modulus of the vibration-proof base. Since the protrusion is provided on the inner side in the axial direction of the two bent portions in the cross section including the shaft center, the vibration-proof base when a large vibration in the axial direction is input by the protrusion and the bent portion having a large Young's modulus. The excessive displacement of can be regulated. As a result, there is an effect that the durability can be improved by restricting the axial displacement while ensuring the characteristics of the vibration-proof substrate.

  According to the bush of the second aspect, since the vibration-proof base is preliminarily compressed in the radial direction between the outer cylinder and the inner cylinder due to the reduced diameter of the outer cylinder, the radial spring constant can be appropriately set. . In addition, in the cross section including the shaft center, the bottom is located inside the axial direction of each of the two bent portions or at the axial position of each of the started points, so that the bent portion is pre-compressed to the anti-vibration base. Can be prevented from being granted. Therefore, in addition to the effect of the first aspect, there is an effect that the spring constant in the radial direction of the vibration-proof base can be appropriately set.

  According to the bush of the third aspect, the bent portion is set such that the minimum value of the inner diameter is smaller than the maximum value of the outer diameter of the protruding portion. Thereby, the overlap margin of radial direction can be ensured between a projection part and a bending part. Due to the overlap margin, in addition to the effect of the first or second aspect, it is possible to improve the restriction effect of excessive displacement of the vibration-proof base when a large axial vibration is input. Furthermore, since there is an overlap margin, even if the vibration-proof substrate is peeled off or broken, there is an effect that the inner cylinder can be prevented from coming off from the outer cylinder and completely separating them.

  According to the bush of the fourth aspect, since the protruding portion of the protruding portion made of the rubber-like elastic body protrudes toward the bent portion positioned outside in the axial direction, large vibration in the axial direction is input. A protrusion can be interposed between the protrusion and the bent portion. As a result, in addition to the effect of any one of claims 1 to 3, there is an effect that an impact when the protrusion and the bent part interfere can be suppressed by the convex part.

It is an axial sectional view of a bush in a 1st embodiment of the present invention. It is an expanded sectional view of the bush which expands and shows the part shown by II of FIG. It is an axial sectional view of the molded product before the outer cylinder is reduced in diameter. It is an axial sectional view of a bush in a 2nd embodiment. It is an expanded sectional view of the bush which expands and shows the part shown by V of FIG. It is an axial sectional view of the molded product before the outer cylinder is reduced in diameter. It is an axial direction sectional view of a bush in a 3rd embodiment. It is an axial direction sectional view of a bush in a 4th embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an axial cross-sectional view of the bush 10 in the first embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of the bush 10 showing a portion indicated by II in FIG. As shown in FIG. 1, the bush 10 includes an inner cylinder 20, an outer cylinder 30 that is coaxially disposed at a distance from the outer periphery 21 of the inner cylinder 20, a rubber-like elastic body, and the inner cylinder 20. An anti-vibration base 40 interposed between the outer cylinder 30 and the outer cylinder 30 is provided.

  The inner cylinder 20 is a member formed in a pipe shape from a rigid material such as a steel material or an aluminum alloy. The inner cylinder 20 is attached to a mating member by inserting a shaft-shaped member (not shown) such as a bolt and fixing the shaft-shaped member to the mating member (not shown). The inner cylinder 20 is provided with a protrusion 22 at the center in the axial direction of the outer periphery 21. The protrusion 22 is formed integrally with the inner cylinder 20 and bulges outward in the radial direction over the circumferential direction. The protrusion 22 has a cylindrical top surface 23 formed so as to be parallel to the axis O of the inner cylinder 20 and an inclined surface 24 formed so that the outer diameter gradually decreases toward the outer side in the axial direction. And. The inclined surface 24 is inclined downward with respect to the top surface 23 with a gradient of about 40 ° toward the outer side in the axial direction.

  The outer cylinder 30 is a member formed in a cylindrical shape having a substantially constant thickness by a plastically deformable rigid material such as a steel material or an aluminum alloy. The outer cylinder 30 is attached to a mating member by being press-fitted into the mating member (not shown). The outer cylinder 30 is formed to be slightly shorter than the inner cylinder 20, has an inner diameter that is larger by a predetermined dimension than the outer diameter of the protrusion 22 (top surface 23), and is spaced apart from the inner cylinder 20 in the radial direction. It is arranged coaxially. The outer cylinder 30 is formed with two bent portions 31 by bending both ends in the axial direction about 40 degrees radially inward.

  The two bent portions 31 are plastically deformed starting from predetermined locations at both axial ends of the outer cylinder 30 as starting points 32, and are reduced in diameter so that the inner diameter gradually decreases from the starting point 32 toward the outer side in the axial direction. The In the cross section including the axis O (the cross section in the axial direction), the two bent portions 31 have two starting points 32 positioned outside in the axial direction from the boundary between the top surface 23 and the inclined surface 24 of the protrusion 22. . As a result, the outer cylinder 30 having the bent portion 31 is formed in a shape in which the inner peripheral surface follows the outer periphery 21 of the inner cylinder 20, the top surface 23 of the protrusion 22, and the inclined surface 24.

  The anti-vibration base body 40 is a substantially cylindrical member that is interposed between the inner cylinder 20 and the outer cylinder 30 and is formed of a rubber-like elastic body. In this embodiment, the vibration-proof base body 40 is formed by vulcanization molding of a rubber material. It is formed. The anti-vibration base 40 has an inner peripheral surface vulcanized and bonded to the outer periphery 21 of the inner cylinder 20, the top surface 23 and the inclined surface 24 of the protrusion 22, and the outer peripheral surface is vulcanized and bonded to the inner peripheral surface of the outer cylinder 30. Is done. Thereby, the vibration isolating base 40 integrally connects the inner cylinder 20 and the outer cylinder 30. The antivibration base body 40 is formed with an annular curb 41 that makes one round in the circumferential direction on the end face in the axial direction.

  As shown in FIG. 2, the two corners 41 are formed in such a depth that the bottom 44 reaches the inner side in the axial direction from the starting point 32 of the bent portion 31 of the outer cylinder 30 in the cross section including the axis O. As a result, the spring 41 can ensure the soft spring characteristics in the radial direction and the axial direction of the vibration-proof base 40.

  Returning to FIG. By providing the anti-vibration base 40 with the curb 41, the thin cylindrical inner cylinder film part 42 integrally formed with the anti-vibration base 40 is formed on the outer periphery 21 of the inner cylinder 20 and the inclined surface 24 of the protrusion 22. Is formed. The inner cylindrical membrane portion 42 has an axially outer end surface located outside the axial end surface of the bent portion 31 formed in the outer tube 30 in the axial direction in a cross section including the axis O.

  Further, by providing the anti-vibration base body 40 with the curb 41, the thin cylindrical outer cylinder film portion 43 integrally formed with the anti-vibration base body 40 is formed on the inner peripheral surface of the outer cylinder 30 (bent portion 31). Is formed. The outer cylinder film part 43 is located at a position where the outer end face in the axial direction is shifted inward in the axial direction by a predetermined distance from the end face of the outer cylinder 30. Specifically, the outer end surface in the axial direction of the outer cylindrical membrane portion 43 is located in the vicinity of the middle in the axial direction of the inclined surface 24 of the protrusion 22 provided on the inner cylinder 20 in the cross section including the axis O. .

  Next, a method for manufacturing the bush 10 will be described with reference to FIG. FIG. 3 is an axial sectional view of the molded body 50 before the outer cylinder 30 is reduced in diameter. The bush 10 is manufactured by reducing the diameter of the outer cylinder 30 of the molded body 50. The molded body 50 is manufactured by placing the inner cylinder 20 and the outer cylinder 30 in a mold (not shown) and vulcanizing and molding a rubber material. In the molded body 50, the radial width (the radial distance between the inner cylindrical membrane portion 42 and the outer cylindrical membrane portion 43) decreases as the straight 41 moves from the opening toward the inner bottom 44 in the axial direction. It is formed.

  After removing the molded body 50 from the molding die (not shown), the outer cylinder 30 is reduced in diameter in the axial direction so that the inner diameter of the outer cylinder 30 of the molded body 50 is reduced. The bent portions 31 are formed by bending both ends radially inward. The bent portion 31 is formed such that the minimum value D1 of the inner diameter (see FIG. 2) is smaller than the maximum value D2 of the outer diameter of the protrusion 22. Thereby, the bush 10 is manufactured. When the outer cylinder 30 is reduced in diameter in the axial direction, the bush 10 is imparted with radial pre-compression to the vibration-proof base 40. Thereby, the spring constant in the radial direction of the vibration isolation base 40 can be set as appropriate.

  Here, in the cross section including the axial center O, the curb 41 is pre-compressed to the anti-vibration base body 40 by the bent portion 31 because the bottom portion 44 is positioned inward in the axial direction from the starting points 32 of the two bent portions 31. Can be prevented from being granted. As a result, it is possible to appropriately set the radial spring constant of the vibration isolating base 40 while preventing the bent portion 31 from affecting the characteristics of the vibration isolating base 40.

  The bush 10 has an inner cylinder 20 attached to a vibration side member (not shown) and an outer cylinder 30 attached to a vehicle body (not shown). As a result, the vehicle body and the vibration-side member are vibration-proof connected by the bush 10. When vibration is input to the bush 10 when the vehicle is traveling, the vibration isolating base 40 is elastically deformed to absorb vibration and prevent vibration transmission. The bush 10 is formed in such a depth that the bottom 44 reaches the inner side in the axial direction from the starting point 32 of the bent portion 31 of the outer cylinder 30 in the cross section including the axial center O. The soft spring characteristics in the radial direction can be secured. Further, since the axial deformation of the vibration isolator base 40 is mainly shear deformation, a soft spring characteristic in the axial direction can be ensured.

  Further, since both the inner cylindrical membrane portion 42 and the outer cylindrical membrane portion 43 are formed in a thin film shape, the radial distance between the outer cylindrical membrane portion 43 and the inner cylindrical membrane portion 42 (the straight 41). Can be secured. Since the inner cylinder film part 42 and the outer cylinder film part 43 can be prevented from interfering with each other when the inner cylinder 20 and the outer cylinder 30 are relatively displaced in the twisting direction, the twisting direction of the inner cylinder 20 and the outer cylinder 30 can be prevented. The relative displacement amount can be secured. At this time, since the deformation of the anti-vibration base body 40 is mainly shear deformation, a soft spring characteristic in the twisting direction can be secured.

  Here, when a large axial vibration is input to the bush 10, the inner cylinder 20 and the outer cylinder 30 are relatively displaced in the axial direction. The protrusion 22 protruding from the inner cylinder 20 toward the outer cylinder 30 is formed of a rigid material, and an inner cylinder film portion 42 made of a thin rubber-like elastic body is formed on the surface (the inclined surface 24). Therefore, the Young's modulus in the axial direction of the inner cylindrical membrane portion 42 and the protrusion 22 is larger than the Young's modulus in the axial direction of the vibration-isolating base 40. Since the protrusion 22 is provided on the inner side in the axial direction of the two bent portions 31 in the cross section including the axis O, the bush 10 has a large axial direction due to the interference between the protrusion 22 and the bent portion 31 having a large Young's modulus. Excessive displacement of the anti-vibration base body 40 when vibration is input can be restricted. As a result, it is possible to improve the durability by restricting the axial displacement of the anti-vibration base 40 when excessive vibration is input while securing the characteristics of the anti-vibration base 40.

  In addition, since the end surface of the outer cylindrical membrane portion 43 formed on the inner peripheral surface of the bent portion 31 is displaced inward in the axial direction of the bent portion 31, the outer cylindrical membrane portion is disposed at the axial end portion of the bent portion 31. The distance in the axial direction between the end portion in the axial direction of the bent portion 31 and the inner cylindrical membrane portion 42 can be increased by the amount that 43 is omitted. Therefore, the amount of relative displacement in the axial direction until the bent portion 31 and the protruding portion 22 interfere with each other can be increased. As a result, a wide linear region in the axial direction can be secured by the anti-vibration base body 40 until the bent portion 31 and the protruding portion 22 interfere with each other. On the other hand, when the bent portion 31 and the protruding portion 22 interfere with each other, a non-linear characteristic in which the spring stiffens rapidly is obtained, and the relative displacement between the bent portion 31 and the protruding portion 22 is restricted. When the bent portion 31 and the protruding portion 22 interfere with each other, the inner cylindrical membrane portion 42 made of a rubber-like elastic body is interposed between the bent portion 31 and the protruding portion 22, so that the shock can be buffered. And the generation of abnormal noise can be suppressed.

  Further, since the minimum value D1 of the inner diameter of the bent portion 31 is set to be smaller than the maximum value D2 of the outer diameter of the protruding portion 22, the radial overlap between the protruding portion 22 and the bent portion 31 ( D2-D1) can be secured. Due to the overlapping margin, the projection 22 and the bent portion 31 can face each other when a large axial vibration is input to the bush 10, so that the effect of restricting the excessive displacement of the vibration-isolating base 40 can be improved. Furthermore, since there is an overlap margin, even if the vibration isolation base 40 is peeled off or broken, it is possible to prevent the inner cylinder 20 from coming off from the outer cylinder 30 and completely separating them.

  Next, a second embodiment will be described with reference to FIGS. In 1st Embodiment, when the bending part 31 and the projection part 22 interfered, the case where the nonlinear characteristic which a spring stiffens rapidly was acquired was demonstrated. On the other hand, in 2nd Embodiment, when the bending part 31 and the projection part 22 interfere, the bush 60 from which a soft spring characteristic is acquired is demonstrated. In addition, about the part same as the part demonstrated in 1st Embodiment, the same code | symbol is attached | subjected and the following description is abbreviate | omitted. 4 is an axial cross-sectional view of the bush 60 in the second embodiment, FIG. 5 is an enlarged cross-sectional view of the bush 60 showing a portion indicated by V in FIG. 4, and FIG. It is an axial sectional view of the molded body 70 before being reduced in diameter.

  As shown in FIG. 4, the bush 60 includes an inner cylinder 20, an outer cylinder 30 that is coaxially disposed on the outer periphery of the inner cylinder 20 at a distance, and a rubber-like elastic body. An anti-vibration base 40 interposed between the cylinder 30 and the cylinder 30 is provided. The anti-vibration base body 40 is formed with a curb 41 on the axial end face. By the curb 41, the inner cylinder film part 42 is formed on the outer periphery 21 of the inner cylinder 20 and the inclined surface 24 of the protrusion 22, and the outer cylinder film part 61 is formed on the inner peripheral surface of the bent part 31 of the outer cylinder 30. . The outer cylinder film part 61 is a thin cylindrical part integrally formed with the vibration isolating base 40, and the end face on the outer side in the axial direction is substantially the same position as the end face of the outer cylinder 30 (the chamfered boundary part). Is formed.

  Here, the manufacturing method of the bush 60 is demonstrated with reference to FIG. The bush 60 is manufactured by reducing the diameter of the outer cylinder 30 of the molded body 70. The molded body 70 is manufactured by placing the inner cylinder 20 and the outer cylinder 30 in a mold (not shown) and vulcanizing and molding a rubber material. The outer cylinder film portion 61 is formed integrally with the vibration isolation base 40 on the inner peripheral surfaces of both ends of the outer cylinder 30 in the axial direction. The outer cylinder film portion 61 is formed by abutting a part of the molding die against the end surface (the chamfered boundary portion) of the outer cylinder 30, forming a cavity on the inner peripheral surface of the outer cylinder 30, and injecting a rubber material into the cavity. Molded with. Since the cavity is formed by abutting a part of the molding die against the end surface (the chamfered boundary portion) of the outer cylinder 30, even if there is a dimensional variation in the outer cylinder 30, the inner peripheral surface of the outer cylinder 30 and the molding die ( It is possible to make it difficult to create a gap with the not shown. As a result, it is difficult to cause a problem that the rubber material leaks from the gap caused by the dimensional variation of the outer cylinder 30 and the dirt adheres to the mold.

  Returning to FIG. The inner cylindrical membrane portion 42 is integrally formed with a plurality of convex portions 62 that protrude outward in the axial direction and the radial direction of the inclined surface 24 of the protruding portion 22. The plurality of convex portions 62 project radially with respect to the axis O, and each of the convex portions 62 is formed in a protruding shape extending along the axis O. As shown in FIG. 5, the convex portion 62 has an axial cross section that is coupled to an outer side 63 that extends linearly toward the outer side in the axial direction, and an end portion on the outer side in the axial direction of the outer side 63. It forms in the substantially triangular shape provided with the hypotenuse 64 which inclines downward toward the inner side of radial direction as it goes to the outer side of a direction. The part where the outer side 63 and the oblique side 64 of the convex part 62 intersect is located radially inward and axially inward of the bent part 31. In the cross section including the axis O, the convex portion 62 has an obtuse angle between the outer side 63 and the oblique side 64.

  The inner cylindrical membrane portion 42 is provided with a plurality of concave portions 65 (see FIG. 4) in the circumferential direction with the convex portion 62 interposed therebetween. The recess 65 is a part where the outer periphery 21 of the inner cylinder 20 is exposed by omitting the rubber film, and is located at a position adjacent to the part where the hypotenuse 64 (see FIG. 5) and the inner cylinder film part 42 intersect in the circumferential direction. Is provided. The recess 65 is formed so as to extend in a streak pattern along the axis O, and in the cross section including the axis O, the inner cylindrical membrane portion 42 has a film thickness as it approaches the recess 65 outward in the axial direction. Is formed to be thin.

  When a large axial vibration is input to the bush 60, the inner cylinder 20 and the outer cylinder 30 are relatively displaced in the axial direction, and the outer cylinder film part 61 and the convex part formed on the inner peripheral surface of the bent part 31. 62 abuts. Since the convex portion 62 is thin in the circumferential direction and easily deformed, the static spring characteristics can be gradually increased by the deformation of the convex portion 62. When the inner cylinder 20 and the outer cylinder 30 are further relatively displaced in the axial direction, the further displacement between the inner cylinder 20 and the outer cylinder 30 is caused by the protruding portion 22 and the bent portion 31 having a Young's modulus larger than that of the vibration-proof base 40. Is regulated. Therefore, according to the bush 60, it is possible to achieve both a soft spring characteristic when the convex portion 62 is deformed by receiving a load and displacement control by the protruding portion 22 and the bent portion 31 after the convex portion 62 is deformed.

  In addition, the convex part 62 is formed using the inclined surface 24 of the projection part 22, and in the cross section including the axis O, the intersection angle of the outer side 63 and the oblique side 64 is an obtuse angle. Compared to the case where the intersection angle with the oblique side 64 is formed at an acute angle, the rubber volume of the convex portion 62 can be increased. As a result, the durability of the convex portion 62 can be ensured.

  In addition, since the inner cylindrical membrane portion 42 is formed so that the film thickness decreases in the cross section including the axis O toward the outer side in the axial direction and closer to the concave portion 65, the inner cylindrical membrane portion 42 is formed into a certain film. By increasing the rubber volume of the convex portion 62 as compared with the case where the thickness is increased, an increase in the spring characteristics of the convex portion 62 in the axial direction and the radial direction can be suppressed. Furthermore, since the convex portion 62 is formed across the plurality of concave portions 65 formed side by side in the circumferential direction, by increasing the rubber volume of the convex portion 62 as compared with the case where the concave portion 65 is not provided, the convex portion 62 is formed. Increase in the spring characteristics of the axial direction and the radial direction of the portion 62 can be suppressed. As a result, it can suppress that the convex part 62 influences the spring characteristic of the vibration isolator base 40, and can ensure the soft spring characteristic of the radial direction of the vibration isolator base 40, and an axial direction.

  Next, a third embodiment will be described with reference to FIG. In 1st and 2nd embodiment, the case where the projection part 22 was integrally molded with the inner cylinder 20 was demonstrated. In contrast, in the third embodiment, a case where the ring-shaped protrusion 92 is attached to the inner cylinder 90 will be described. FIG. 7 is an axial sectional view of the bush 80 according to the third embodiment. As shown in FIG. 7, the bush 80 includes an inner cylinder 90, an outer cylinder 100 that is coaxially disposed at a distance from an outer periphery 91 of the inner cylinder 90, a rubber-like elastic body, and the inner cylinder 90. An anti-vibration base 110 is provided between the outer cylinder 100 and the outer cylinder 100.

  The inner cylinder 90 is a member formed in a pipe shape from a rigid material such as a steel material or an aluminum alloy. The inner cylinder 90 is provided with two protrusions 92 at two locations on both sides of the outer periphery 91 in the axial direction. The protrusions 92 are members formed in a ring shape from a rigid material such as a steel material or an aluminum alloy, and are spaced from each other in the axial direction and are fitted at two locations on the outer periphery 91 of the inner cylinder 90.

  The outer cylinder 100 is a member formed in a cylindrical shape having a substantially constant thickness by a plastically deformable rigid material such as a steel material or an aluminum alloy. The outer cylinder 100 is formed to have a length slightly shorter than the inner cylinder 90, has an inner diameter larger than the outer diameter of the protrusion 92 by a predetermined dimension, and is arranged coaxially at a distance on the radially outer side of the inner cylinder 90. The The outer cylinder 100 is formed with two bent portions 101 by bending both axial ends inward in the radial direction.

  The two bent portions 101 are portions that are plastically deformed starting from predetermined locations on both ends of the outer cylinder 100 in the axial direction, and the inner diameter gradually decreases from each starting point 102 toward the outside in the axial direction. In the two bent portions 101, in the cross section including the axis O, the portion having the smallest inner diameter (the end portion in the axial direction of the bent portion 101) is outside in the axial direction than the portion having the largest outer diameter of the protruding portion 92. Located in each. Note that the maximum value of the outer diameter of the protrusion 92 is set to be the same as the minimum value of the inner diameter of the bent portion 101.

  The anti-vibration base 110 is a substantially cylindrical member interposed between the inner cylinder 90 and the outer cylinder 100 and made of a rubber-like elastic body. The peripheral surface is vulcanized and bonded, and the outer peripheral surface is vulcanized and bonded to the inner peripheral surface of the outer cylinder 100. As a result, the vibration isolation base 110 integrally connects the inner cylinder 90 and the outer cylinder 100. The anti-vibration base 110 is formed with annular curls 111 that make one round in the circumferential direction on the end faces in the axial direction. In the cross section including the axis O, the two corners 111 are formed to a depth at which the bottom 144 reaches the inner side in the axial direction from the starting point 102 of the bent portion 101 of the outer cylinder 100. As a result, the spring 111 can secure the soft spring characteristics in the radial direction and the axial direction of the vibration-proof base 110.

  As the vibration isolator base 110 is provided with the straight 111, a thin cylindrical inner cylinder film portion 112 integrally formed with the vibration isolator base 110 is formed on the outer periphery 91 and the protrusion 92 of the inner cylinder 90. . The outer cylinder 100 (bent part 101) is formed with a thin cylindrical outer cylinder film part 113 integrally formed with the vibration isolation base 110 on the inner peripheral surface.

  In order to manufacture the bush 80, first, the inner cylinder 90 is connected to the cylindrical outer cylinder 100 in which the bent portion 101 is not formed via the vibration isolation base 110. Next, while bending the outer cylinder 100 in the axial direction so that the inner diameter of the outer cylinder 100 is reduced, both ends in the axial direction are bent radially inward to form the bent portion 101. Thereby, the bush 80 is manufactured.

  According to this bush 80, the same operation and effect as the bush 10 in the first embodiment can be realized. Further, since the protrusions 92 are spaced apart from each other in the axial direction and are fitted at two locations on the outer periphery 91 of the inner cylinder 90, the volume can be reduced as compared with the protrusions 22 of the bush 10 in the first embodiment. . A rubber-like elastic body (anti-vibration base 110) is filled between the protrusions 92 (the inner side in the axial direction of the two protrusions 92), but the specific gravity of the rubber-like elastic body is set smaller than the specific gravity of the protrusions 22. Thus, the bush 80 can be reduced in weight by the amount that can reduce the volume of the protrusion 92.

  Next, a fourth embodiment will be described with reference to FIG. In the first to third embodiments, the case where the protrusions 22 and 92 are covered with the vibration isolation bases 40 and 110 and the inner cylindrical film portions 42 and 112 (rubber-like elastic bodies) has been described. That is, in the first to third embodiments, the protrusions 22 and 92 are provided on the inner cylinders 20 and 90 before the vibration isolation base 40 is formed. In contrast, in the fourth embodiment, a case will be described in which the protrusion 140 is provided on the inner cylinder 90 after the vibration-proof base 130 is formed. In addition, about the part same as the part demonstrated in 3rd Embodiment, the same code | symbol is attached | subjected and the following description is abbreviate | omitted. FIG. 8 is a sectional view in the axial direction of the bush 120 in the fourth embodiment.

  As shown in FIG. 8, the bush 120 is composed of an inner cylinder 90, an outer cylinder 100 that is coaxially arranged at a distance on the outer side in the radial direction of the inner cylinder 90, and a rubber-like elastic body, and the inner cylinder 90. And an antivibration base 130 interposed between the outer cylinder 100 and the outer cylinder 100. The anti-vibration base 130 is a substantially cylindrical member that is interposed between the inner cylinder 90 and the outer cylinder 100 and made of a rubber-like elastic body, and an inner peripheral surface is added to the outer periphery 91 of the inner cylinder 90. At the same time, the outer peripheral surface is vulcanized and bonded to the inner peripheral surface of the outer cylinder 100. The anti-vibration base 130 is formed with an annular curb 131 that makes one round in the circumferential direction on the end face in the axial direction.

  In the cross section including the axis O, the two corners 131 are formed to a depth at which the bottom 133 reaches the inner side in the axial direction from the starting point 102 of the bent portion 101 of the outer cylinder 100. As a result, the spring 111 can secure the soft spring characteristics in the radial direction and the axial direction of the vibration-proof base 130. By providing the edge 131 on the vibration isolation base 130, a thin cylindrical outer cylinder film portion 132 formed integrally with the vibration isolation base 130 is formed on the inner peripheral surface of the outer cylinder 110 (bent portion 101). Is done.

  The inner cylinder 90 is provided with two protrusions 140 at two locations on both sides of the outer periphery 91 in the axial direction. The protrusions 140 are members formed in a ring shape by a rubber-like elastic body, and are disposed at two locations on both sides in the axial direction of the vibration isolation base 130. The two protrusions 140 are fitted at two locations on the outer periphery 91 of the inner cylinder 90, and the inner peripheral surface is bonded to the outer periphery 91 of the inner cylinder 90. The protrusion 140 is set such that the Young's modulus in the axial direction is larger than the Young's modulus in the axial direction of the vibration isolation base 130, and the Young's modulus in the radial direction is greater than the Young's modulus in the radial direction of the vibration isolation base 130. Is also set to a large value.

  In the two bent portions 101, in the cross section including the axis O, the portion having the smallest inner diameter (the end portion in the axial direction of the bent portion 101) is outside in the axial direction than the portion having the largest outer diameter of the protruding portion 92. Located in each. The protrusion 140 is set such that the maximum outer diameter is larger than the minimum inner diameter of the bent portion 101. In addition, the outer shape of the protruding portion 140 is set so that the inner peripheral surface and the outer peripheral surface of the bent portion 101 and the outer tubular membrane portion 132 are separated from each other, and the protruding portion 140 is disposed on the inner side in the radial direction of the protruding portion 140.

  In order to manufacture the bush 120, first, the inner cylinder 90 is connected to the cylindrical outer cylinder 100 in which the bent portion 101 is not formed via the vibration isolation base 130. Next, protrusions 140 are provided at positions on both sides in the axial direction of the vibration isolation base 130 of the inner cylinder 90, and then the outer cylinder 100 is reduced in diameter along the axial direction so that the inner diameter of the outer cylinder 100 is reduced. Meanwhile, the bent portion 101 is formed by bending both ends in the axial direction radially inward. Thereby, the bush 120 is manufactured.

  According to this bush 120, the same operation and effect as the bush 10 in the first embodiment can be realized. Further, since the protruding portion 140 is disposed inside the two bent portions 101 in the axial direction (inside the straight 131), when a large axial vibration is input to the bush 120, the inner cylinder 90 and the outer cylinder 100 are disposed. Are relatively displaced in the axial direction, and the outer tubular membrane portion 132 formed on the inner peripheral surface of the bent portion 101 and the protruding portion 140 come into contact with each other. Since the protrusion 140 is set such that the Young's modulus in the axial direction is larger than the Young's modulus in the axial direction of the vibration isolation base 130, the relative displacement in the axial direction between the inner cylinder 90 and the outer cylinder 100 is restricted. The As a result, it is possible to improve durability by restricting axial displacement while ensuring the characteristics of the vibration-proof base 130.

  Further, when a large radial vibration is input to the bush 120, the inner cylinder 90 and the outer cylinder 100 are relatively displaced in the radial direction, and the outer cylinder film portion 132 and the protrusion formed on the inner peripheral surface of the bent portion 101 are projected. The part 140 contacts. Since the protrusion 140 is set to have a radial Young's modulus larger than the radial Young's modulus of the vibration isolation base 130, the relative displacement in the radial direction between the inner cylinder 90 and the outer cylinder 100 is restricted. The As a result, it is possible to improve the durability by restricting the radial displacement while ensuring the characteristics of the anti-vibration base 130.

  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. For example, the numerical values and shapes (for example, the dimensions and shapes of the components, the angles of the bent portions 31 and 101, etc.) given in the above embodiment are merely examples, and other numerical values and shapes can naturally be adopted.

  In addition, in each of the above embodiments, a part or a plurality of parts of the configuration of the other embodiments are added to the embodiment or replaced with a part or a plurality of parts of the configuration of the embodiment. The embodiment may be modified and configured.

  For example, the protrusions 92 described in the third embodiment can be provided on the bushes 10 and 60 in place of the protrusions 22 of the bushes 10 and 60 in the first and second embodiments. . Further, instead of expanding the inner cylinder 20 of the bushes 10, 60 to form the projection 22, a projection 22, which is a member different from the inner cylinder 20, is prepared, and the projection 22 is connected to the inner cylinder 20. Of course, it is possible to attach it.

  In each of the above-described embodiments, the case where the bushes 10, 60, 80, 120 are provided in the automobile suspension device has been described. However, the present invention is not necessarily limited to this, and the relative displacement in the axial direction is restricted while suppressing vibration transmission. Of course, it is possible to apply to various uses. Moreover, it is naturally possible to apply not only for automobiles but also to various industrial machines.

  In each of the above embodiments, the bottom portions 44, 114, 133 of the straightenings 41, 111, 131 formed on the anti-vibration bases 40, 110, 130 are the two bent portions 31, 101 in the cross section including the axis O. Although the case where it located in the axial direction inner side rather than the starting points 32 and 102 was demonstrated, it does not necessarily restrict to this. Of course, it is possible to provide the bottom portions 44, 114, and 133 of the curls 41, 111, and 131 at the positions in the axial direction of the starting points 32 and 102 of the two bent portions 31 and 101 in the cross section including the axis O. Also in this case, it is possible to prevent pre-compression from being applied to the vibration isolation bases 40, 110, and 130 when the bent portions 31 and 101 are formed. As a result, it is possible to prevent the bent portions 31 and 101 from affecting the characteristics of the vibration isolation bases 40, 110 and 130.

  In the third embodiment, the case where the ring-shaped protrusion 92 is attached to the inner cylinder 90 has been described. However, the present invention is not necessarily limited to this, and a metal or synthetic resin wire is used for the inner cylinder 90. Of course, it is possible to form the protrusion 92 by winding it around the wire.

  In the fourth embodiment, the bush 120 including the rubber-like elastic protrusion 140 is described. However, the material of the protrusion 140 is not limited to this, and a protrusion of another material is selected. Is of course possible. Examples of the protrusions of other materials include synthetic resin or metal protrusions having a higher Young's modulus in the axial direction than the Young's modulus in the axial direction of the vibration-proof base 130.

  In the fourth embodiment, the case where the protrusion 140 is bonded to the outer periphery 91 of the inner cylinder 90 has been described. However, the present invention is not necessarily limited thereto, and the protrusion 140 is attached to the inner cylinder 90 using other means. Of course, it is possible to fix to. As other means, when the inner cylinder 90 is fixed to a mating member (not shown) using a shaft-like member (not shown) such as a bolt, it is interposed between the mating member and the protrusion 140. A cylindrical member having a cylindrical shape. The inner diameter of the cylindrical member is set slightly larger than the outer diameter of the inner cylinder 90, and the outer diameter of the cylindrical member is set smaller than the minimum value of the inner diameter of the bent portion 101. The length of the cylindrical member is set to the distance between the axially outer end surface of the protrusion 140 and the end surface of the inner cylinder 90. Accordingly, when the inner cylinder 90 is fixed to a counterpart member (not shown), the inner cylinder 90 is inserted into the cylindrical member, and the cylindrical member is interposed between the counterpart member and the protruding portion 140. Can do. Since the cylindrical member can prevent the protrusion 140 from moving outward in the axial direction, the protrusion 140 can be fixed to the inner cylinder 90 without bonding.

  It is also possible to extend the protrusion 140 long toward the axially outward direction of the inner cylinder 90 and hold the outer end surface of the protrusion 140 in the axial direction with a mating member (not shown). Also in this case, since the protrusion 140 can be prevented from moving outward in the axial direction, the protrusion 140 can be fixed to the inner cylinder 90 without bonding.

10, 60, 80, 120 Bush 20, 90 Inner cylinder 21, 91 Outer periphery 22, 92, 140 Protruding part 30, 100 Outer cylinder 31, 101 Bent part 32, 102 Starting point 40, 110, 130 Anti-vibration base 41, 111, 131 Straight 44, 114, 133 Bottom 62 Convex D1 Minimum inner diameter D2 Maximum outer diameter O Axis

Claims (4)

An inner cylinder,
An outer cylinder disposed coaxially with a distance to the outside in the radial direction of the inner cylinder;
Comprising a rubber-like elastic body and an antivibration base that is interposed between the outer cylinder and the inner cylinder and integrally connects them;
The outer cylinder includes two bent portions whose axial ends are bent radially inward,
The anti-vibration base is provided with an annular curl that is formed on the end face in the axial direction and makes one round in the circumferential direction,
In the cross section including the axial center, the curb has a bottom portion located at an inner side in the axial direction from the starting points of the two bent portions or at an axial position of the starting points, respectively.
The inner cylinder includes a protrusion provided on the outer periphery and protruding toward the outer cylinder,
The protrusion has an axial Young's modulus set to a value larger than an axial Young's modulus of the vibration-proof base, and an axially inner side of the two bent portions in a cross section including the axial center. Bush characterized by being provided in.   2. The bush according to claim 1, wherein the anti-vibration base is provided with a radial pre-compression between the outer cylinder and the inner cylinder by a diameter reduction of the outer cylinder.   The bush according to claim 1, wherein the bent portion has a minimum inner diameter set smaller than a maximum outer diameter of the protrusion.   The said protrusion part is provided with the convex part which protrudes toward the said bending part located in the outer side of an axial direction while being comprised from a rubber-like elastic body. The bush described.

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