Cylindrical vibration isolation device

Abstract

To provide a cylindrical vibration control device of a new structure, enabling a body rubber elastic body to realize required performance at a higher level, by increasing shape flexibility of the body rubber elastic body.SOLUTION: In a cylindrical vibration control device 10, an inner shaft member 12 and an outer shaft member 14 are coupled by a body rubber elastic body 16. The outer cylinder member 14 includes a rubber outer member 22 fixed to an outer peripheral surface of the body rubber elastic body 16, and a cylindrical sleeve member 20 in which the rubber outer member 22 is pressed and fixed. The rubber outer member 22 is provided with a window portion 36 penetrating in a shaft orthogonal direction. On an axial outer side of the window portion 36 in the rubber outer member 22, a press-in rubber 56 covering an outer peripheral surface of the rubber outer member 22 is provided. The press-in rubber 56 is sandwiched and compressed between the rubber outer member 22 and the sleeve member 20. The press-in rubber 56 is provided with a recessed releasing portion 62 opening to the outer peripheral surface.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a cylindrical vibration isolator applied to engine mounts, suspension bushes, etc. of automobiles.

Background Art

[0002] Conventionally, cylindrical vibration isolators applied to engine mounts, suspension bushes, etc. of automobiles are known. The cylindrical vibration isolator has a structure in which an inner shaft member and an outer cylinder member are connected by a main body rubber elastic body, for example, as disclosed in Japanese Patent Application Laid-Open No. 10-047403 (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the cylindrical vibration isolator of Patent Document 1, since the outer peripheral surface of the main body rubber elastic body is fixed to the inner peripheral surface of the outer cylinder member, the main body rubber elastic body is formed by a mold that is inserted in the axial direction with respect to the outer cylinder member. Therefore, adjustment settings such as spring characteristics of the main body rubber elastic body were performed by providing a through hole penetrating in the axial direction in the main body rubber elastic body, as also shown in Patent Document 1.

[0005] However, in the main body rubber elastic body formed only by such a mold that is demolded in the axial direction, the degree of freedom of the shape is limited, so there were cases where the performance such as spring characteristics required for the main body rubber elastic body could not be fully realized.

[0006] The problem to be solved by the present invention is to provide a cylindrical vibration isolation device with a novel structure that can achieve a higher level of performance required for the main body rubber elastic material by increasing the degree of freedom in the shape of the main body rubber elastic material. [Means for solving the problem]

[0007] The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is illustrative and can be combined with others as appropriate. Furthermore, the multiple components described in each embodiment can be recognized and adopted as independently as possible, and can be combined with any component described in another embodiment as appropriate. Thus, the present invention is not limited to the embodiments described below, and various other embodiments can be realized.

[0008] The first embodiment is a cylindrical vibration damping device in which an inner shaft member and an outer cylindrical member are connected by a main rubber elastic body, wherein the outer cylindrical member includes a rubber outer member fixed to the outer circumferential surface of the main rubber elastic body and a cylindrical sleeve member into which the rubber outer member is press-fitted and fixed, the rubber outer member is provided with a window portion that penetrates in a direction perpendicular to the axis, and on the axially outer side of the window portion of the rubber outer member, a press-fit rubber is provided that covers the outer circumferential surface of the rubber outer member, and the press-fit rubber is sandwiched and compressed between the rubber outer member and the sleeve member, and the press-fit rubber is provided with a concave relief portion that opens to the outer circumferential surface.

[0009] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, the presence of a window in the rubber outer member allows for the appropriate setting of the shape of the outer surface exposed through the window in the main rubber elastic body, thereby ensuring a greater degree of freedom in the shape of the main rubber elastic body. Therefore, the spring characteristics and durability of the cylindrical vibration isolation device can be set more appropriately.

[0010] The inventors' research revealed that forming a window in the rubber outer member reduces the deformation rigidity of the rubber outer member, making deformation of the axially outer portion of the window particularly problematic when the rubber outer member is press-fitted into the sleeve member in the axial direction. Therefore, a press-fit rubber is provided on the outer circumferential surface of the axially outer window portion of the rubber outer member, allowing the rubber outer member to be press-fitted into the sleeve member, and a concave relief portion is formed in the press-fit rubber. As a result, when the rubber outer member is press-fitted into the sleeve member, the deformation of the press-fit rubber allowed by the relief portion reduces the press-fit reaction force acting on the rubber outer member on the axially outer side of the window portion, thereby preventing deformation of the rubber outer member with the window portion formed therein.

[0011] The second embodiment is a cylindrical vibration damping device as described in the first embodiment, wherein the main body rubber elastic body is provided with a recess that opens to the outer circumferential surface, and the recess is open to the outer circumferential surface through the window portion of the rubber outer member.

[0012] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, by providing recesses on the outer surface of the main rubber elastic body that is exposed to the outer periphery through the window, the spring characteristics and durability of the main rubber elastic body can be adjusted with a greater degree of freedom.

[0013] A third embodiment is a cylindrical vibration isolation device described in the second embodiment, wherein a first stopper projection is provided that protrudes from the bottom of the recess toward the opening.

[0014] In the cylindrical vibration isolation device constructed according to this embodiment, the window portion is covered by the sleeve member by press-fitting and fixing the rubber outer member into the sleeve member. As a result, the relative displacement between the inner shaft member and the outer cylindrical member in the radial direction in which the first stopper projection protrudes is limited by the contact of the first stopper projection with the sleeve member. Therefore, the amount of deformation of the main rubber elastic body connecting the inner shaft member and the outer cylindrical member is limited, thereby improving the durability of the main rubber elastic body.

[0015] The fourth embodiment is a cylindrical vibration isolation device described in any one of the first to third embodiments, wherein the rubber outer member is composed of a pair of outer segmented bodies, these outer segmented bodies have a common shape, and each of these outer segmented bodies is provided with the window portion.

[0016] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, for example, by bringing a pair of outer segmented bodies closer together, it is possible to apply a sufficiently large radial pre-compression to the main rubber elastic body connecting the inner shaft member and the rubber outer member.

[0017] The pair of outer halves share a common shape with a window section, which facilitates manufacturing through parts commonality and avoids problems such as incorrect assembly of the pair of outer halves.

[0018] The fifth aspect is a cylindrical vibration damping device described in any one of the first to fourth aspects, wherein the main body rubber elastic body comprises a pair of rubber arms that radially connect the inner shaft member and the rubber outer member, and a pair of axially penetrating holes are provided between the circumferential directions of the pair of rubber arms.

[0019] According to the cylindrical vibration isolation device constructed in accordance with this embodiment, the main body rubber elastic body is provided with a pair of rubber arms that extend radially through a pair of perforated holes, thereby enabling adjustment of spring characteristics and improvement of durability.

[0020] The fifth embodiment is suitably adopted in combination with the second and third embodiments. That is, by adopting a combination of recesses that open radially on the outer circumferential surface of a pair of rubber arms and perforations that open axially between the circumferential directions of the pair of rubber arms, it becomes possible to design the shape of the main rubber elastic body with a greater degree of freedom, thereby obtaining a greater degree of freedom in adjusting spring characteristics and the like.

[0021] Further, the fifth aspect is preferably adopted in combination with the fourth aspect. That is, by arranging a pair of outer split bodies to face each other in the radial direction so as to be fixed to the outer peripheral ends of each of the pair of rubber arms, the pre-compression direction of the main body rubber elastic body due to the mutual approach displacement of the pair of outer split bodies substantially coincides with the stretching direction of the pair of rubber arms, and the pair of rubber arms can be efficiently pre-compressed in the stretching direction, and the durability of the pair of rubber arms can be advantageously ensured.

[0022] The sixth aspect is the cylindrical vibration isolator described in the fifth aspect, in which a second stopper protrusion protruding from the inner shaft member side to the through hole is provided in the radial direction orthogonal to the stretching direction of the pair of rubber arms.

[0023] According to the cylindrical vibration isolator having the structure according to this aspect, when the second stopper protrusion protruding into the through hole abuts against the outer cylinder member, the relative displacement amount between the inner shaft member and the outer cylinder member in the radial direction in which the second stopper protrusion protrudes is restricted, and an improvement in the durability of the main body rubber elastic body can be realized.

[0024] The seventh aspect is the cylindrical vibration isolator described in any one of the first to sixth aspects, in which the relief portion is in the form of a groove extending in the circumferential direction.

[0025] According to the cylindrical vibration isolator having the structure according to this aspect, a relief portion can be formed in the press-fitted rubber over a wide range in the circumferential direction, and the deformation of the press-fitted rubber can be allowed by the relief portion over a wide range in the circumferential direction.

[0026] The eighth aspect is the cylindrical vibration isolator described in any one of the first to seventh aspects, in which the portions of the press-fitted rubber where the relief portions are disengaged from both axial sides have an axial width dimension larger than the depth dimension of the relief portions.

[0027] According to the cylindrical vibration isolator structured according to this aspect, since the press-fit rubbers located on both axial sides with respect to the escape portion are in a relatively wide and flat shape, the fixing force by press-fitting between the rubber outer member and the sleeve member is effectively exerted. Further, by dispersing the press-fit reaction force acting on the press-fit rubber, damage to the press-fit rubber is less likely to occur.

[0028] A ninth aspect is the cylindrical vibration isolator described in any one of the first to eighth aspects, wherein an outer peripheral surface of the rubber outer member is covered with a covering rubber including the press-fit rubber, and the covering rubber is formed with a press-fit force adjustment groove that opens on the outer peripheral surface and extends in the axial direction.

[0029] According to the cylindrical vibration isolator structured according to this aspect, since the outer peripheral surface of the rubber outer member is covered with the covering rubber even in portions other than the outer side in the axial direction of the window portion, a concentrated action of the press-fit reaction force on the press-fit rubber is avoided.

[0030] When assembling the rubber outer member to the sleeve member by press-fitting, deformation of the covering rubber is allowed by the press-fit force adjustment groove formed in the covering rubber, so that it is possible to prevent an excessive press-fit force from being required and the assembly work from becoming difficult.

[0031] A tenth aspect is the cylindrical vibration isolator described in the ninth aspect, wherein the press-fit force adjustment groove is provided in an intermediate portion in the axial direction of the covering rubber without reaching the axial end of the covering rubber.

[0032] According to the cylindrical vibration isolator structured according to this aspect, it is possible to prevent water or the like from entering the press-fit force adjustment groove from the outside, and to prevent a decrease in the fixing force between the rubber outer member and the sleeve member or a decrease in the durability of the rubber outer member.

Advantages of the Invention

[0033] According to the present invention, in the cylindrical vibration isolator, by increasing the degree of freedom in the shape of the main body rubber elastic body, the performance required for the main body rubber elastic body can be realized at a higher level. [Brief explanation of the drawing]

[0034] [Figure 1] Front view showing a cylindrical vibration isolation device as the first embodiment of the present invention. [Figure 2] Section II-II in Figure 1 [Figure 3] Section III-III in Figure 1 [Figure 4] Figure 2, section IV-IV [Figure 5] Front view of the integrally vulcanized molded product constituting the cylindrical vibration damping device shown in Figure 1. [Figure 6] Plan view of the integrally vulcanized product shown in Figure 5. [Figure 7] Right side view of the integrally vulcanized product shown in Figure 5. [Figure 8] Figure 5, section VIII-VIII [Figure 9] Figure 7, section IX-IX [Figure 10] Plan view of the rubber outer member constituting the integrally vulcanized molded product shown in Figure 5. [Figure 11] Right side view of the rubber outer member shown in Figure 10. [Modes for carrying out the invention]

[0035] Embodiments of the present invention will be described below with reference to the drawings.

[0036] Figures 1 to 4 show a cylindrical vibration isolation device 10 as a first embodiment of the present invention. The cylindrical vibration isolation device 10 has a structure in which an inner shaft member 12 and an outer cylindrical member 14 are elastically connected by a main rubber elastic body 16. In this embodiment, a sleeve member 20 is attached in an external state to an integrally vulcanized molded product 18 of the main rubber elastic body 16, which includes the inner shaft member 12 and the outer cylindrical member 14. In the following description, as a general rule, the vertical direction refers to the vertical direction in Figure 1, the left-right direction refers to the left-right direction in Figure 1, and the front-back direction refers to the left-right direction in Figure 2.

[0037] As shown in Figures 5 to 9, the integrally vulcanized molded product 18 has a structure in which an inner shaft member 12 and a rubber outer member 22 are elastically connected by a main rubber elastic body 16. The inner shaft member 12 is substantially cylindrical in shape and has a central hole 24 with a substantially circular cross-section that penetrates in the axial direction, and is made of metal or a hard synthetic resin. The inner shaft member 12 has stepped diameters at both ends in the axial direction. The inner shaft member 12 integrally includes a first stopper projection 26 that protrudes to both sides in the vertical direction and a second stopper projection 28 that protrudes to both sides in the horizontal direction. As shown in Figures 2 and 3, the axial length dimension of the first stopper projection 26 is smaller than that of the second stopper projection 28, and as shown in Figure 9, the circumferential width dimension is larger than that of the second stopper projection 28.

[0038] The rubber outer member 22 is generally thin-walled, large-diameter, and substantially cylindrical in shape, and is composed of a pair of outer segmented bodies 30, 30. The outer segmented body 30 is substantially semi-cylindrical in shape and is made of a metal such as iron. Flat portions 32 are provided at both circumferential ends of the outer segmented body 30. The flat portions 32 extend substantially parallel to the tangent at the circumferential end of the outer segmented body 30 and are provided at both axial ends of the circumferential end of the outer segmented body 30. At the circumferential end of the outer segmented body 30, a plurality of communication holes 34 are formed that penetrate radially in the axial central portion of the outer segmented body 30 where the flat portions 32 are not provided. The cross-sectional shape of the communication holes 34 is not limited, but in this embodiment it is circular in cross-section, and three are provided axially separated from each other between the flat portions 32, 32 on both axial sides.

[0039] The outer segment 30 has a window portion 36 that penetrates radially. As shown in Figures 10 and 11, the window portion 36 is formed to penetrate the central portion of the outer segment 30 in both the axial and circumferential directions, and is a through-hole with a substantially rectangular cross-section with rounded corners. In this embodiment, the circumferential length of the window portion 36 is set to be at least 1 / 2 and at least 2 / 3 of the total circumferential length of the outer segment 30, as shown in Figure 9. In this embodiment, the axial length of the window portion 36 is set to be at least 1 / 3 and at least 2 / 3 of the total axial length of the outer segment 30, as shown in Figure 11. On both sides of the window portion 36 in the outer segment 30, there are axially extending portions 38 that extend in the axial direction. On both sides of the window portion 36 in the outer segment 30, there are circumferentially extending portions 40 that extend in the circumferential direction.

[0040] As shown in Figures 9 and 11, the pair of outer sections 30, 30 are arranged facing each other in the vertical direction to constitute the rubber outer member 22. In this embodiment, the pair of outer sections 30, 30 have a common shape, and a window portion 36 is formed in each of the pair of outer sections 30, 30. Therefore, the rubber outer member 22 has a pair of window portions 36, 36 that penetrate through it in the vertical direction. By having the pair of outer sections 30, 30 have a common shape, the number of parts can be reduced, and problems such as incorrect assembly due to incorrect combination of outer sections can be prevented when constructing the rubber outer member 22.

[0041] The inner shaft member 12 and the rubber outer member 22 are interconnected by the main rubber elastic body 16. Specifically, the inner circumferential surface of the main rubber elastic body 16, which is cylindrical as a whole, is vulcanized and bonded to the inner shaft member 12, and the outer circumferential surface is vulcanized and bonded to the rubber outer member 22, and these inner shaft member 12 and rubber outer member 22 are radially connected by the main rubber elastic body 16. The main rubber elastic body 16 is formed as an integrally vulcanized molded product 18 comprising the inner shaft member 12 and the rubber outer member 22 (a pair of outer segmented bodies 30, 30). In the integrally vulcanized molded product 18, the pair of outer segmented bodies 30, 30 are separated from each other in the vertical direction at their circumferential ends, and can approach each other in the radial direction (vertical direction) by the elastic deformation of the main rubber elastic body 16.

[0042] As shown in Figure 9, a pair of cut holes 42, 42 are formed in the main rubber elastic body 16. The cut holes 42 are provided on both the left and right sides of the inner shaft member 12 and penetrate the main rubber elastic body 16 in the axial direction. The divided portions of the pair of outer divisions 30, 30 in the rubber outer member 22 are located on the outer circumference side of the pair of cut holes 42, 42. The pair of second stopper protrusions 28, 28 of the inner shaft member 12 protrude from the inner shaft member 12 side into each cut hole 42 in the radial direction (left-right direction) perpendicular to the first stopper protrusions 26, 26, and are located away from the inner circumference side relative to the circumferential ends of the pair of outer divisions 30, 30. The surface including the tip surface of the second stopper protrusion 28 is covered by a second stopper rubber 44 integrally formed with the main rubber elastic body 16.

[0043] The formation of a pair of grooved holes 42, 42 gives the main rubber elastic body 16 a pair of rubber arms 46, 46 that extend in the vertical direction. In other words, grooved holes 42 are formed between the pair of rubber arms 46, 46 in the main rubber elastic body 16 in the circumferential direction. The rubber arms 46 are fixed to the outer split body 30 to the circumferentially extended portion 40 located on both axially outer sides of the window portion 36 and to the axially extended portion 38 located on both circumferentially outer sides of the window portion 36. Therefore, the inner shaft member 12 and the rubber outer member 22 are interconnected in one radial direction (vertical direction) by the pair of rubber arms 46, 46. By forming the pair of rubber arms 46, 46 in the main rubber elastic body 16 with the pair of grooved holes 42, 42, the spring characteristics of the main rubber elastic body 16 can be adjusted. In other words, for example, in the vertical direction, which is the extension direction of the rubber arm 46, a high spring characteristic can be set due to the compression spring of the rubber arm 46, and in the horizontal direction, which is perpendicular to the extension direction of the rubber arm 46, a low spring characteristic can be set due to the shear spring of the rubber arm 46.

[0044] A recess 48 is formed in the rubber arm 46 of the main rubber elastic body 16. The recess 48 opens to the outer peripheral end face of the rubber arm 46. The outer peripheral opening shape of the recess 48 substantially corresponds to the window portion 36, and it is open to the outer periphery through the window portion 36. The first stopper projection 26 of the inner shaft member 12 protrudes from the inner shaft member 12 side from the bottom of the recess 48 toward the opening and is located inside the recess 48, and is exposed to the outer periphery through the window portion 36. The surface including the tip surface of the first stopper projection 26 is covered by the first stopper rubber 50 which is integrally formed with the main rubber elastic body 16.

[0045] A pair of windows 36, 36 are formed in the rubber outer member 22 fixed to the outer circumferential surface of the main rubber elastic body 16, making it possible to form recesses 48, 48 that open to the outer circumferential surface of the main rubber elastic body 16. In other words, in order to form the recesses 48 that open to the outer circumferential surface of the main rubber elastic body 16, a mold for shaping the inner surface of the recesses 48 needs to be inserted through the rubber outer member 22, and the windows 36 are provided in the rubber outer member 22 as holes for this molding mold to pass through. Therefore, by providing the windows 36 in the rubber outer member 22, the degree of freedom in the shape of the main rubber elastic body 16 can be greatly increased, and the spring characteristics and durability of the main rubber elastic body 16 can be set to a higher level.

[0046] The outer circumferential surface of the rubber outer member 22 is covered by a covering rubber 52 integrally formed with the main rubber elastic body 16. The covering rubber 52 consists of a first outer circumferential rubber 54 that covers the outer circumferential surface of each axially extended portion 38 of the rubber outer member 22, and a second outer circumferential rubber 56 that acts as a press-fit rubber covering the outer circumferential surface of each circumferentially extended portion 40. The covering rubber 52 is integrally continuous with the main rubber elastic body 16 through a pair of window portions 36, 36 and a plurality of communication holes 34. The main rubber elastic body 16 and the covering rubber 52 can also be integrally connected between the circumferential directions of a pair of outer segmented bodies 30, 30.

[0047] The first outer rubber 54 is provided with a first groove 58 which serves as an adjustment groove for the pressure applied. As shown in Figures 6 and 7, the first groove 58 extends linearly in the axial direction. The first groove 58 extends over substantially the entire axial length of the first outer rubber 54, but does not reach the axial end of the first outer rubber 54, and the axial end of the first outer rubber 54 is continuous in the circumferential direction without being interrupted by the first groove 58. As shown in Figure 9, the first groove 58 penetrates the first outer rubber 54 and reaches the outer surface of the rubber outer member 22, and the rubber outer member 22 is exposed to the outer periphery at the first groove 58.

[0048] The second outer rubber 56 is provided with a second groove 60 which serves as an adjustment groove for the pressure applied. As shown in Figures 6 to 8, the second groove 60 extends linearly in the axial direction. The second groove 60 penetrates the second outer rubber 56 and reaches the outer surface of the rubber outer member 22, so that the rubber outer member 22 is exposed to the outer periphery at the second groove 60. The second groove 60 extends along substantially the entire axial length of the second outer rubber 56, but does not reach the axial end of the second outer rubber 56, so that the axial end of the second outer rubber 56 is continuous in the circumferential direction without being interrupted by the second groove 60. Five second grooves 60 are formed in the second outer rubber 56 and are arranged at substantially equal intervals in the circumferential direction.

[0049] The molding portion of the covering rubber 52 in the mold for molding the main rubber elastic body 16 is inserted into the window portions 36, 36 to form recesses 48, 48, and thus has a vertically divided structure. Therefore, the inner surfaces of both side walls of the first groove 58 and the second groove 60 are both extended approximately vertically, and the shape is such that it does not hinder the removal of the mold.

[0050] The second outer rubber 56, which is press-fitted rubber, is provided with a relief portion 62. The relief portion 62 is concave, opening onto the outer surface of the second outer rubber 56. The relief portion 62 is formed in the axial middle portion of the second outer rubber 56. The relief portion 62 is formed to a depth that does not reach the outer surface of the rubber outer member 22. In this embodiment, the relief portion 62 is groove-shaped and extends in the circumferential direction, and is provided between the second concave grooves 60, 60 located at both circumferential ends of the second outer rubber 56. The relief portion 62 is divided into four parts in the circumferential direction by the second concave grooves 60. The axial dimension of the relief portion 62 is smaller than the axial dimension of the second concave grooves 60, and the second concave grooves 60 protrude axially from the relief portion 62 on both sides. The portions that constitute the walls on both axial sides of the relief portion 62 in the second outer rubber 56 are convex portions 64 that protrude outward from the circumferentially extended portion 40. The convex portion 64 has an axial width dimension that is larger than the depth dimension of the relief portion 62 (the dimension of the convex portion 64 protruding from the bottom surface of the relief portion 62), and extends in the circumferential direction with a flattened cross-sectional shape. The axial width dimension of the convex portion 64 is smaller than the axial width dimension of the relief portion 62.

[0051] A sleeve member 20 is attached to the integrally vulcanized molded product 18, which has the structure described above, in an externally fitted state. The sleeve member 20 is a large-diameter, roughly cylindrical shape and is made of metal or the like.

[0052] The integrally vulcanized molded product 18 is then press-fitted into the sleeve member 20 in the axial direction with the pair of outer segments 30, 30 brought closer to each other in the vertical direction, and the circumferential ends of the outer segments 30, 30 in contact to form a cylindrical rubber outer member 22 as a whole. By bringing the pair of outer segments 30, 30 closer to each other during press-fitting into the sleeve member 20, a vertical pre-compression is applied to the pair of rubber arms 46, 46 of the main rubber elastic body 16. This reduces the tensile stress acting on the main rubber elastic body 16 in use, thereby improving the durability of the main rubber elastic body 16. In this embodiment, since the rubber outer member 22 is a segmented structure consisting of a pair of outer segments 30, 30, pre-compression can be applied to the pair of rubber arms 46, 46 without requiring deformation of the rubber outer member 22. Therefore, it is easy to set a larger pre-compression amount for the pair of rubber arms 46, 46, and by ensuring a pre-compression amount corresponding to the magnitude of the vibration input, the durability of the main rubber elastic body 16 can be improved more advantageously.

[0053] The integrally vulcanized molded product 18 is press-fitted into the sleeve member 20 while the covering rubber 52, which includes a first outer rubber 54 and a second outer rubber 56, is sandwiched and compressed between the rubber outer member 22 and the sleeve member 20 in the radial direction. The outer cylindrical member 14 of this embodiment is composed of the rubber outer member 22 and the sleeve member 20, as the rubber outer member 22 of the integrally vulcanized molded product 18 is press-fitted and fixed into the sleeve member 20 via the covering rubber 52.

[0054] In this embodiment, the first groove 58 and the second groove 60 allow deformation of the coated rubber 52 compressed between the rubber outer member 22 and the sleeve member 20, thereby adjusting the radial compression spring of the coated rubber 52. As a result, the pressing force required to press-fit the integrally vulcanized molded product 18 into the sleeve member 20 is adjusted, making the assembly work of the integrally vulcanized molded product 18 and the sleeve member 20 easier.

[0055] The rubber outer member 22 has windows 36, 36, which means that the deformation rigidity is relatively small in each circumferentially stretched portion 40 located axially outward from the windows 36, 36, and there is a risk that the circumferentially stretched portion 40 will deform when the integrally vulcanized molded product 18 is pressed into the sleeve member 20. Therefore, a relief portion 62 is provided in the second outer peripheral rubber 56 of the covering rubber 52 provided on the outer peripheral surface of the circumferentially stretched portion 40, thereby reducing the press-fit reaction force acting on the circumferentially stretched portion 40 during press-fitting. That is, when the integrally vulcanized molded product 18 is pressed into the sleeve member 20, the convex portion 64 of the second outer peripheral rubber 56 is pressed against the inner peripheral surface of the sleeve member 20 and compressed in the protruding direction, but because the relief portion 62 is provided in the second outer peripheral rubber 56, deformation of the compressed convex portion 64 is allowed on both sides in the axial direction, and the compression spring of the convex portion 64 is reduced. As a result, when the integrally vulcanized molded product 18 is press-fitted into the sleeve member 20, the press-fit reaction force exerted on the circumferentially stretched portion 40 of the rubber outer member 22 by the compression of the convex portion 64 is reduced, preventing unintended deformation of the circumferentially stretched portion 40.

[0056] The relief portion 62 in this embodiment extends in the circumferential direction and is provided along substantially the entire length of the circumferentially extended portion 40. Therefore, deformation of the convex portion 64 is permitted over a wider range in the circumferential direction by the relief portion 62, and the press-fit reaction force acting on the circumferentially extended portion 40 during press-fitting can be reduced more effectively.

[0057] The convex portion 64 provided on the outer circumferential surface of the circumferentially stretched portion 40 of the rubber outer member 22 has a flattened cross-sectional shape in which the axial dimension is larger than the protruding height dimension, resulting in excellent shape stability. When the integrally vulcanized molded product 18 is press-fitted into the sleeve member 20, the convex portion 64 is compressed radially between the rubber outer member 22 and the sleeve member 20, and the protruding tip surface slides against the inner circumferential surface of the sleeve member 20. Even under the action of such external forces during press-fitting, deformation such as tilting of the convex portion 64 is unlikely to occur, and a stable press-fitting method is achieved. In addition, because the convex portion 64 is wide, the radial press-fitting reaction force acting on the convex portion 64 is dispersed, making damage to the convex portion 64 less likely to be a problem.

[0058] The integrally vulcanized molded product 18 is assembled to the sleeve member 20 by press-fitting, thereby closing the window portions 36, 36 with the sleeve member 20. The portion of the sleeve member 20 that closes the window portions 36, 36 faces the first stopper protrusions 26, 26 with a predetermined stopper clearance on the outer circumference. When vertical vibration is input between the inner shaft member 12 and the outer cylindrical member 14, the first stopper protrusions 26 come into contact with the sleeve member 20 via the first stopper rubber 50, thereby limiting the relative vertical displacement of the inner shaft member 12 and the outer cylindrical member 14. This prevents excessive deformation of the main rubber elastic body 16, improving the durability of the main rubber elastic body 16.

[0059] Furthermore, as the integrally vulcanized molded product 18 is assembled to the sleeve member 20 by press-fitting, the portion of the rubber outer member 22 that faces the second stopper projection 28 in the left-right direction is superimposed on the sleeve member 20 and reinforced. When left-right vibration is input between the inner shaft member 12 and the outer cylindrical member 14, the second stopper projection 28 contacts the rubber outer member 22 via the second stopper rubber 44, thereby limiting the relative displacement of the inner shaft member 12 and the outer cylindrical member 14 in the left-right direction. This prevents excessive deformation of the main rubber elastic body 16 and improves the durability of the main rubber elastic body 16.

[0060] Although embodiments of the present invention have been described in detail above, the present invention is not limited by its specific description. For example, the rubber outer member is not necessarily limited to a divided structure composed of a pair of outer divided parts. That is, the rubber outer member may be, for example, a cylindrical shape without divided parts, or a cylindrical shape with a C-shaped cross-section divided only in a part in the circumferential direction.

[0061] The pair of slit holes 42, 42 are not essential, nor is it essential that the main rubber elastic body 16 have a pair of rubber arms 46, 46.

[0062] The first stopper projection 26 and the second stopper projection 28 may be provided individually or neither may be provided. Furthermore, the stopper projection may be provided so as to protrude from the rubber outer member toward the inner shaft member, or it may be composed of a member separate from either the inner shaft member or the rubber outer member.

[0063] The relief portion is not limited to a groove shape extending in the circumferential direction, but may also be a spot-like recess, for example. Furthermore, it is possible to provide multiple relief portions for a single circumferentially extended portion 40. For example, multiple groove-shaped relief portions extending in the circumferential direction may be provided spaced apart from each other in the axial direction, or multiple spot-like relief portions may be provided spaced apart from each other in the circumferential direction.

[0064] The relief portion is preferably located in the middle of the axial direction of the press-fit rubber, but may also be located at the axial end, for example. [Explanation of Symbols]

[0065] 10. Cylindrical Vibration Isolator (First Embodiment) 12 Inner shaft member 14 Outer cylindrical member 16 Main body rubber elastic body 18. One-piece vulcanized molded product 20 Sleeve component 22 Rubber outer component 24 Center hole 26 First stopper projection 28 Second stopper projection 30 Outer divisions 32 Flat area 34 Communication hole 36 Window section 38 Axial extension part 40 Circumferential extension part 42 slit holes 44 Second stopper rubber 46 Rubber Arms 48. Recess 50 First stopper rubber 52 Coated rubber 54 First outer rubber 56. Second outer rubber (press-fit rubber) 58 First groove (pressure adjustment groove) 60 Second groove (pressure adjustment groove) 62 Escape Department 64 Convex part

Claims

1. A cylindrical vibration isolation device in which an inner shaft member and an outer cylindrical member are connected by a main body rubber elastic material, The outer cylindrical member includes a rubber outer member fixed to the outer circumferential surface of the main body rubber elastic body, and a cylindrical sleeve member into which the rubber outer member is press-fitted and fixed. The rubber outer member is provided with a window portion that penetrates in a direction perpendicular to the axis, On the axially outer side of the window portion of the rubber outer member, a press-fit rubber is provided that covers the outer circumferential surface of the rubber outer member, and the press-fit rubber is sandwiched and compressed between the rubber outer member and the sleeve member. The press-fit rubber is provided with a concave relief section opening on its outer surface, forming a cylindrical vibration damping device.

2. The aforementioned main body rubber elastic material is provided with a recess opening on its outer surface, The cylindrical vibration damping device according to claim 1, wherein the recess is open to the outer circumference through the window portion of the rubber outer member.

3. The cylindrical vibration damping device according to claim 2, wherein a first stopper projection is provided that protrudes from the bottom of the recess toward the opening.

4. The cylindrical vibration isolation device according to claim 1 or 2, wherein the rubber outer member is composed of a pair of outer segmented bodies, these outer segmented bodies have a common shape, and each of these outer segmented bodies is provided with the window portion.

5. The main body rubber elastic body is provided with a pair of rubber arms that connect the inner shaft member and the rubber outer member in the radial direction. The cylindrical vibration damping device according to claim 1 or 2, wherein a pair of axially penetrating holes are provided between the circumferentially connected rubber arms.

6. The cylindrical vibration damping device according to claim 5, wherein a second stopper projection is provided that protrudes from the inner shaft member side into the recessed hole in a radial direction perpendicular to the extension direction of the pair of rubber arms.

7. The cylindrical vibration damping device according to claim 1 or 2, wherein the relief portion is groove-shaped and extends in the circumferential direction.

8. The cylindrical vibration damping device according to claim 1 or 2, wherein the portion of the press-fit rubber that is separated from the relief portion on both sides in the axial direction has an axial width dimension that is greater than the depth dimension of the relief portion.

9. The outer circumferential surface of the rubber outer member is covered with a covering rubber including the press-fit rubber, The cylindrical vibration damping device according to claim 1 or 2, wherein the covering rubber has an opening on its outer surface and an axially extending pressure input adjustment groove.

10. The cylindrical vibration damping device according to claim 9, wherein the pressure input adjustment groove is provided in the axial intermediate portion of the covering rubber without reaching the axial end of the covering rubber.

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