Cylindrical vibration isolator

Abstract

Provided is a cylindrical vibration isolator of a novel structure that can stably exert the press-in fixing force of an outer cylinder member made of synthetic resin to a retainer and can position the outer cylinder member and the retainer with high accuracy in the axial direction. A cylindrical vibration isolator (10) has a structure in which an inner shaft member (12) and an outer cylinder member (14) made of synthetic resin are linked by a main body rubber elastic body (16), wherein the outer cylinder member has a structure in which a cylindrical portion (20) protrudes from an inner peripheral end of a flange portion (22) that is ring plate-shaped, a press-in rubber (38) is fixed to an outer peripheral surface of the cylindrical portion, and an axial surface (46) of the side from which the cylindrical portion (20) protrudes in the flange portion is not covered with the press-in rubber and is exposed, a notch (24) that penetrates in the radial direction is provided at an axial end portion of the outer cylinder member (14) including the flange portion, and a linking rubber (52) that links the main body rubber elastic body and the press-in rubber is provided at the notch.

Description

Technical Field

[0001] This invention relates to a cylindrical vibration damping device for use in motor vehicle engine mounts and the like. Background Technology

[0002] Previously, cylindrical vibration damping devices were used in motor vehicles, such as engine mounts, subframe mounts, and suspension bushings. For example, as disclosed in Japanese Patent Application Publication No. 2015-161356 (Patent Document 1), the cylindrical vibration damping device has a structure in which an inner shaft member and an outer cylinder member are connected by a main rubber elastomer.

[0003] Incidentally, while previous outer cylinder components were made of metal, resin-based outer cylinder components have been studied for purposes such as reducing the weight of cylindrical vibration damping devices. Patent Document 1 also provides an example of an outer cylinder component made of synthetic resin.

[0004] However, if the outer cylinder component, which is installed on other components such as the vehicle body by pressing into the assembly hole, is made of resin, the stress generated by pressing into the assembly hole will continue to act, making it prone to plastic deformation. There is a risk that the pressing reaction force will decrease due to the aging of the outer cylinder component.

[0005] Therefore, in Patent Document 1, a press-in rubber is provided on the outer peripheral surface of the outer cylinder component, and the elasticity of the press-in rubber is used to exert the fixing force of the outer cylinder component relative to the assembly hole. As a result, the aging of the resin outer cylinder component is less likely to affect the fixing force generated by pressing it into the assembly hole.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2015-161356 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in the structure of Patent Document 1, since the surface of the flange portion provided on the outer cylinder member is used as a cover rubber to connect the press-in rubber and the main rubber elastomer, it is also taken into consideration that the relative position of the outer cylinder member and the assembly hole in the axial direction may be deviated due to the elasticity of the cover rubber between the flange portion and the assembly hole.

[0011] The problem to be solved by the present invention is to provide a novel cylindrical vibration damping device that can stably exert the pressing and fixing force of the synthetic resin outer cylinder component into the assembly hole, and can accurately position the outer cylinder component and the assembly hole in the axial direction.

[0012] means for solving problems

[0013] Hereinafter, preferred embodiments for mastering the present invention will be described. However, the embodiments described below are exemplary and can be appropriately combined with each other. Furthermore, the various constituent elements described in each embodiment can be identified and used as independently as possible, and can also be appropriately combined with any constituent element described in other embodiments. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be implemented.

[0014] The first type is a cylindrical vibration damping device, which has a structure in which an inner shaft component and an outer cylinder component made of synthetic resin are connected by a main body rubber elastomer. The outer cylinder component has a structure in which a cylindrical portion extends axially from the inner peripheral end of an annular flange portion. Press-in rubber is fixed to the outer peripheral surface of the cylindrical portion, and the axial surface of the side of the flange portion on which the cylindrical portion extends is not covered by the press-in rubber and is exposed. A radially penetrating notch is provided at the axial end of the outer cylinder component containing the flange portion, and a connecting rubber connecting the main body rubber elastomer and the press-in rubber is provided in the notch.

[0015] According to the cylindrical vibration damping device formed in accordance with this method, a press-in rubber is fixed to the outer peripheral surface of the cylindrical portion of the outer cylindrical member made of synthetic resin. When the outer cylindrical member is inserted relative to the assembly hole, the press-in rubber is radially compressed between the outer cylindrical member and the peripheral wall of the assembly hole, and the elasticity of the press-in rubber fixes the outer cylindrical member to the assembly hole. By adopting such a rubber press-in structure, the plastic deformation (aging) of the synthetic resin outer cylindrical member over time is less likely to affect the fixing force of the cylindrical vibration damping device to the assembly hole, and a stable assembly state of the cylindrical vibration damping device relative to the assembly hole can be maintained.

[0016] In the outer cylinder component, the flange portion that overlaps with the opening end face of the assembly hole is not fixed with press-in rubber, and the exposed flange portion directly overlaps with the opening end face of the assembly hole. Therefore, the rubber will not be compressed between the overlapping surfaces of the flange portion and the opening end face of the assembly hole, thus preventing the outer cylinder component from shifting towards the detachment side relative to the assembly hole due to the elasticity of the rubber.

[0017] In this method, the main rubber elastomer and the press-fit rubber are connected by a connecting rubber provided at a notch in the axial end of the outer cylinder member, including the flange portion. Thus, the main rubber elastomer and the press-fit rubber can be integrally formed without covering the overlapping surface of the flange portion that overlaps with the opening end face of the assembly hole. Furthermore, since the notch is located at the rear end of the cylindrical vibration damping device in the pressing direction relative to the assembly hole, it prevents the notch and connecting rubber from getting stuck on the inner surface of the assembly hole during the initial pressing of the cylindrical vibration damping device relative to the assembly hole, thus preventing increased resistance.

[0018] The second method is based on the cylindrical vibration damping device described in the first method, wherein the connecting rubber is disposed within the notch without protruding axially outward relative to the flange portion.

[0019] For example, if the connecting rubber protrudes from the flange portion toward the side overlapping with the opening end face of the assembly hole, there is a risk that the outer cylinder member may shift axially relative to the assembly hole due to the elasticity of the connecting rubber pressed against the opening end face of the assembly hole. Furthermore, if the connecting rubber protrudes from the flange portion toward the opposite side overlapping with the opening end face of the assembly hole, for example, when pressing the flange portion axially into the assembly hole to insert the outer cylinder member, there is a risk that the connecting rubber protruding axially outward from the flange portion may make it difficult to apply a pressing force to the flange portion. The cylindrical vibration damping device with the structure according to this method solves these problems, and the connecting rubber does not easily obstruct the axial positioning of the outer cylinder member and the assembly hole, or the input to the flange portion during pressing.

[0020] The third method, based on the cylindrical vibration damping device described in the first or second method, involves forming a pair of recessed holes on both radial sides of the inner shaft member in the main rubber elastomer, and providing a pair of rubber arms in the main rubber elastomer. The pair of rubber arms extend radially between the pair of recessed holes in the circumferential direction and connect the inner shaft member and the outer cylinder member to each other. The connecting rubber is arranged on the outer circumferential side of each rubber arm.

[0021] According to the cylindrical vibration damping device formed in accordance with this method, by providing connecting rubber on the outer periphery of a pair of rubber arms, the rubber arms, connecting rubber, and press-in rubber are easily integrally formed during the vulcanization molding of the main rubber elastomer.

[0022] The fourth method, based on the cylindrical vibration damping device described in any of the first to third methods, provides an outer peripheral protrusion that protrudes outward from the pressed-in rubber between the circumferential ends of the flange portion of the notch in the connecting rubber, and an injection gate mark of the rubber material during the forming of the connecting rubber is formed on the outer peripheral protrusion.

[0023] According to the cylindrical vibration damping device formed in accordance with this method, by directly injecting rubber material into the mold cavity of at least a portion of the outer peripheral protrusion located at a position closer to the outer periphery than the pressed rubber during the vulcanization molding of the rubber, the pressed rubber fixed to the outer peripheral surface of the cylindrical part can be formed with good filling properties of the rubber material.

[0024] The fifth method is based on the cylindrical vibration damping device described in any of the first to fourth methods, wherein the axial end of the cylindrical portion on the side opposite to the flange portion is formed as a cylindrical press-in top portion that is continuous throughout the circumference, and the outer peripheral surface of the press-in top portion is not covered by the press-in rubber and is exposed.

[0025] According to the cylindrical vibration damping device with the structure of this embodiment, when pressed into the assembly hole, the pressing tip portion, which is the pressing tip side, is formed into a continuous cylindrical shape without any notches or gaps throughout its circumference. Therefore, by making the pressing tip portion contact the inner circumferential surface of the assembly hole throughout its circumference, the outer cylinder member and the assembly hole are positioned, thereby facilitating the pressing of the outer cylinder member in the appropriate direction relative to the assembly hole. In addition, since the outer circumferential surface of the pressing tip portion is not covered by the pressing rubber and is exposed, the frictional resistance is reduced in the initial stage of pressing.

[0026] Invention Effects

[0027] According to the present invention, the outer cylinder component made of synthetic resin can be stably pressed into the assembly hole, and the outer cylinder component and the assembly hole can be positioned with high axial precision. Attached Figure Description

[0028] Figure 1 This is a front view of the cylindrical vibration damping device as the first embodiment of the present invention.

[0029] Figure 2 yes Figure 1 The image shows a bottom view of the cylindrical vibration damping device.

[0030] Figure 3 yes Figure 1 The right view of the cylindrical vibration damping device shown.

[0031] Figure 4 yes Figure 1 Sectional view IV-IV.

[0032] Figure 5 yes Figure 1 VV sectional view.

[0033] Figure 6 yes Figure 2 Sectional view VI-VI.

[0034] Figure 7 It constitutes Figure 1 The front view of the outer cylinder component of the cylindrical vibration damping device shown.

[0035] Figure 8 yes Figure 7 The right view of the outer cylinder component shown.

[0036] Explanation of reference numerals in the attached figures

[0037] 10: Cylindrical vibration damping device (first embodiment);

[0038] 12: Inner shaft components;

[0039] 14: Outer cylinder components;

[0040] 16: Main body rubber elastomer;

[0041] 18: Center hole;

[0042] 20: Tubular part;

[0043] 22: Flange portion;

[0044] 24: Gap;

[0045] 26: Defective groove;

[0046] 28: Notched hole;

[0047] 30: Rubber arm;

[0048] 32: Stop rubber;

[0049] 34: Inner circumferential cylindrical part;

[0050] 36: Peripheral cylinder;

[0051] 38: Press-in rubber;

[0052] 40 (40a~40c): Circumferential rubber;

[0053] 42: Axial rubber;

[0054] 44: Conical part;

[0055] 46: Contact surface;

[0056] 48: Pressing surface;

[0057] 50: Press into the top part;

[0058] 52: Connecting rubber;

[0059] 54: Peripheral protrusion;

[0060] 56: Connecting rubber;

[0061] 58: Injection gate mark;

[0062] 58a: Inner circumferential injection gate mark;

[0063] 58b: Peripheral injection gate mark;

[0064] 60: Install object components;

[0065] 62: Assembly hole;

[0066] 64: Open end face. Detailed Implementation

[0067] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0068] exist Figures 1-6 The diagram shows a cylindrical vibration damping device 10 as a first embodiment of the present invention. The cylindrical vibration damping device 10 has a structure in which an inner shaft member 12 and an outer cylinder member 14 are connected by a main body rubber elastomer 16. In the following description, in principle, the vertical direction refers to... Figure 1 The up and down directions and the left and right directions refer to... Figure 1 The left and right directions and the front and back directions refer to Figure 2 The up and down directions in the middle.

[0069] The inner shaft member 12 is formed in a generally cylindrical shape with thick walls and a small diameter, and has a central hole 18 with a circular cross-section extending along the axial direction. The inner shaft member 12 is formed, for example, from metal or synthetic resin, and is formed as a rigid member.

[0070] Also Figure 7 , Figure 8 As shown, the outer cylinder member 14 is integrally formed into a generally cylindrical shape with thin walls and a large diameter. The outer cylinder member 14 integrally includes a cylindrical portion 20 and an annular flange portion 22 protruding outward from one axial end (front end) of the cylindrical portion 20. In other words, the outer cylinder member 14 has a structure in which the cylindrical portion 20 extends from the inner circumferential end of the annular flange portion 22 toward the other axial side (rear). The outer cylinder member 14 is a rigid component formed from synthetic resins such as polyamide (PA), polypropylene (PP), and polytetrafluoroethylene (PTFE).

[0071] A pair of notches 24 are formed at the axial end (front end) of the outer cylinder member 14, on one side where the flange portion 22 is provided. The notch 24 is formed to radially penetrate the front end portion of the cylindrical portion 20 and the flange portion 22. Therefore, the notch 24 is a rectangular groove extending radially at the front end portion of the cylindrical portion 20, and the flange portion 22 is circumferentially divided by the notch 24. In this embodiment, the pair of notches 24 are arranged opposite each other radially, and the flange portion 22 is divided into two parts circumferentially by the pair of notches 24.

[0072] The inner shaft member 12 is arranged in an inserted state relative to the outer cylinder member 14, and a main rubber elastomer 16 is formed between the inner shaft member 12 and the outer cylinder member 14. The main rubber elastomer 16 is generally cylindrical in shape, and its inner circumferential surface is vulcanized and bonded to the outer circumferential surface of the inner shaft member 12, and its outer circumferential surface is vulcanized and bonded to the inner circumferential surface of the cylindrical portion 20 of the outer cylinder member 14.

[0073] In the main body rubber elastomer 16, notches 26 extending in a circumferential shape are formed with openings at both ends in the axial direction. A pair of notched holes 28 are formed in the main body rubber elastomer 16, extending in the axial direction. The notched holes 28 are formed on both sides in the vertical direction relative to the inner shaft member 12, and extend in the horizontal direction, with their left and right ends reaching positions on the outer side in the horizontal direction than the inner shaft member 12.

[0074] A pair of rubber arms 30 are formed between the upper and lower surfaces of a pair of recessed holes 28 in the main rubber elastomer 16, extending in the left-right direction and connecting the inner shaft member 12 and the outer cylinder member 14 in the left-right direction. The pair of rubber arms 30 are configured to connect the inner circumferential cylinder portion 34, which is fixed to the outer circumferential surface of the inner shaft member 12, and the outer circumferential cylinder portion 36, which is fixed to the inner circumferential surface of the outer cylinder member 14, to each other in the left-right direction. The axial end face of the rubber arm 30 is formed by the bottom surface of the recessed groove 26, and the inner circumferential cylinder portion 34 and the outer circumferential cylinder portion 36 protrude axially further than the axial end face of the rubber arm 30.

[0075] At a position on the upper and lower outer sides of the main rubber elastomer 16, a pair of stop rubbers 32 are formed, protruding from the outer cylinder member 14 toward the inner shaft member 12. The relative displacement of the inner shaft member 12 and the outer cylinder member 14 in the vertical direction is limited by the contact between the stop rubbers 32 and the inner shaft member 12.

[0076] A press-fit rubber 38 is fixedly attached to the outer circumferential surface of the cylindrical portion 20 of the outer cylinder component 14. For example... Figures 2-6 As shown, the press-in rubber 38 integrally comprises a plurality of circumferential rubbers 40 extending in a ring shape along the circumferential direction, and a plurality of axial rubbers 42 extending in the axial direction between the plurality of circumferential rubbers 40.

[0077] The circumferential rubber 40 is formed as a ring that extends continuously around the entire circumference with a substantially constant cross-section. In this embodiment, the rear end portion of the circumferential rubber 40, which is the pressing-in tip side, is formed as a tapered portion 44 with a decreasing diameter towards the rear, and the front end portion, which is the pressing-in rear end side, extends axially with a substantially constant outer diameter. In this embodiment, three circumferential rubbers, namely circumferential rubbers 40a, 40b, and 40c, are provided spaced apart from each other in the axial direction.

[0078] The circumferential rubber 40a located on the front side is axially spaced rearward relative to the flange portion 22 of the outer cylinder member 14. Moreover, the rear surface of the flange portion 22 is formed as an abutment surface 46 that is not covered by the pressed-in rubber 38 but exposed to the outside. In addition, the front surface of the flange portion 22 is also formed as a pressing surface 48 that is not covered by rubber but exposed to the outside, just like the abutment surface 46.

[0079] The circumferential rubber 40c located at the rear is spaced forward relative to the rear end of the cylindrical portion 20, and the portion of the cylindrical portion 20 further rear than the circumferential rubber 40c is exposed and not covered by the press-in rubber 38. The rear end portion of the cylindrical portion 20 exposed and not covered by the press-in rubber 38 is formed as a continuous cylindrical press-in tip portion 50 throughout its entire circumference. Therefore, the cylindrical portion 20 has a flange portion 22 at one end (front end) on one axial side, and the other end (rear end) on the other axial side is formed as the press-in tip portion 50. In this embodiment, the outer circumferential surface of the press-in tip portion 50 is formed with a substantially constant diameter along its entire axial length, but for example, it can also have a tapered surface with a smaller diameter toward the rear end, which serves as the press-in tip, thereby providing a guiding function when pressed into the assembly hole 62 described later.

[0080] Axial rubber 42 extends linearly along the axial direction, and multiple axial rubbers 42 are spaced apart from each other in the circumferential direction. Multiple axial rubbers 42 are provided between the circumferential rubbers 40a and 40b in the axial direction, and between the circumferential rubbers 40b and 40c in the axial direction. The two ends of the axial rubber 42 located between the circumferential rubbers 40a and 40b are integrally connected to the circumferential rubbers 40a and 40b, connecting them to each other. Similarly, the two ends of the axial rubber 42 located between the circumferential rubbers 40b and 40c are integrally connected to the circumferential rubbers 40b and 40c, connecting them to each other. The protrusion dimension of the axial rubber 42 from the cylindrical portion 20 is smaller than the maximum protrusion dimension of the circumferential rubber 40 from the cylindrical portion 20.

[0081] Since the molding die is removed along the left-right direction, the two circumferential sides of the axial rubber 42 are formed in a shape that will not be undercut during demolding in the left-right direction. The circumferential width of the axial rubber 42 located at the center in the up-down direction is larger than that of the other axial rubbers 42, preferably more than twice that of the other axial rubbers 42.

[0082] Furthermore, in the portion surrounded by the circumferential rubber 40 and the axial rubber 42, the outer peripheral surface of the cylindrical portion 20 can be exposed, and the outer peripheral surface of the cylindrical portion 20 can also be covered by a thin-walled rubber layer.

[0083] A pair of rubber arms 30 and a pair of notches 24 on the outer cylinder member 14 are positioned circumferentially, with the notches 24 located on the outer periphery of each rubber arm 30. The circumferential width of the notch 24 is preferably less than or equal to the circumferential width of the outer end of the rubber arm 30. The circumferential center of the notch 24 preferably coincides with the circumferential center of the rubber arm 30; in this embodiment, it is located at the center in the vertical direction. The notch 24 and the rubber arm 30 are preferably axially separated in projections perpendicular to the axis (left-right direction), and the bottom surface of the notch 24 is preferably located forward of the front end face (bottom surface of the notch 26) of the rubber arm 30.

[0084] A connecting rubber 52, which connects the main rubber elastomer 16 and the press-in rubber 38, is fixedly attached to the notch 24. For example... Figure 4 As shown, the connecting rubber 52 extends radially within the notch 24, its inner circumference being integrally connected to the outer circumferential cylindrical portion 36 of the main rubber elastomer 16, and its outer circumferential side being integrally connected to the press-in rubber 38. In summary, in this embodiment, the main rubber elastomer 16, the press-in rubber 38, and the connecting rubber 52 are formed as a single unit. Given that notches 24 are formed on the outer circumferential sides of each pair of rubber arms 30, it is understood that in this embodiment, the connecting rubber 52 is respectively disposed on the outer circumferential sides of the pair of rubber arms 30, and this pair of connecting rubbers 52 is formed to have approximately the same shape (symmetrical shape).

[0085] The connecting rubber 52 has a peripheral protrusion 54 that protrudes outward. The peripheral protrusion 54 is provided in the segmented portion formed by the notch 24 of the flange portion 22, and its two ends are fixed to the circumferential end face of the flange portion 22. The peripheral protrusion 54 protrudes further outward than the peripheral end of the pressed rubber 38 (circumferential rubber 40). The thickness dimension of the peripheral protrusion 54 in the front-rear direction of the connecting rubber 52 is smaller than the thickness dimension of the flange portion 22, and it is provided within the thickness range of the flange portion 22 without protruding to either side in the front-rear direction relative to the flange portion 22. The connecting rubber 52 is provided in the notch 24 without protruding outward from the flange portion 22 in the front-rear direction.

[0086] like Figure 3 , Figure 4As shown, the connecting rubber 52 is connected to the circumferential rubber 40a via a connecting rubber 56 extending axially from the notch 24 and fixed to the outer peripheral surface of the cylindrical portion 20 of the outer cylinder member 14. The connecting rubber 56 constituting the press-in rubber 38 extends linearly axially with a circumferential width dimension approximately the same as that of the notch 24. The protrusion dimension of the connecting rubber 56 from the cylindrical portion 20 is preferably less than or equal to the protrusion dimension of the circumferential rubber 40 from the cylindrical portion 20; in this embodiment, it is approximately the same as the protrusion dimension of the axial rubber 42 from the cylindrical portion 20. The outer peripheral protrusion 54 of the connecting rubber 52 protrudes to a position further outward than the connecting rubber 56. Furthermore, in this embodiment, the connecting rubber 52 includes a portion that covers the upper end face of the forming portion of the notch 24 in the cylindrical portion 20 and a portion (outer peripheral protrusion 54) fixed to the circumferential end face of the forming portion of the notch 24 in the flange portion 22. Furthermore, as described above, in this embodiment, the peripheral protrusion 54 is provided in the flange portion 22 of the outer cylinder member 14 at the segmented portion formed by the notch 24. Figure 4 In the middle, the peripheral protrusion 54 includes not only a portion that protrudes beyond the peripheral surface of the connecting rubber 56, but also a portion located above the connecting rubber 56.

[0087] like Figure 1 , Figure 4 As shown, injection gate marks 58, serving as traces of injection gates for rubber material, are provided protruding from the outer peripheral cylindrical portion 36 of the main rubber elastomer 16 and the upper surface of the connecting rubber 52. The injection gate marks 58 consist of an inner peripheral injection gate mark 58a on the inner peripheral side and an outer peripheral injection gate mark 58b on the outer peripheral side, respectively located on the outer peripheral sides (left and right outer sides) of a pair of rubber arms 30. At least a portion of the inner peripheral injection gate mark 58a is located closer to the inner peripheral side than the cylindrical portion 20 of the outer cylindrical member 14, preferably entirely located closer to the inner peripheral side than the outer peripheral surface of the cylindrical portion 20. At least a portion of the outer peripheral injection gate mark 58b is located closer to the outer peripheral side than the cylindrical portion 20 of the outer cylindrical member 14, preferably entirely located closer to the outer peripheral side than the inner peripheral surface of the cylindrical portion 20. The outer peripheral injection gate mark 58b is configured to protrude at least partially from the outer peripheral protrusion 54. The outer circumferential injection gate mark 58b preferably overlaps at least a portion of the connecting rubber 56 in its axial projection. The inner circumferential injection gate mark 58a and the outer circumferential injection gate mark 58b are arranged radially at the same position in the circumferential direction, and are configured to be separated from each other in the radial (left-right direction).

[0088] Furthermore, during the integral vulcanization molding of the main rubber elastomer 16, the press-fit rubber 38, and the connecting rubber 52, with the inner shaft member 12 and the outer cylinder member 14 set in the molding die, rubber material is injected into the mold cavity of the molding die from the injection gate mark 58. Thus, the rubber material injected from the inner circumferential injection gate forming the inner circumferential injection gate mark 58a mainly forms the main rubber elastomer 16 and the connecting rubber 52 located on the inner circumferential side of the cylindrical portion 20, while the rubber material injected from the outer circumferential injection gate forming the outer circumferential injection gate mark 58b mainly forms the press-fit rubber 38 and the connecting rubber 52 located on the outer circumferential side of the cylindrical portion 20. In this way, by setting an outer peripheral injection gate for injecting rubber material onto the outer peripheral side of the cylindrical portion 20 separately from the inner peripheral injection gate for injecting rubber material onto the inner peripheral side of the cylindrical portion 20, it is possible to efficiently form a press-fit rubber 38 that is thinner than the main rubber elastomer 16, and the pressure difference between the inner and outer peripheral sides of the cylindrical portion 20 is reduced when the rubber material is injected, thereby suppressing the deformation of the cylindrical portion 20.

[0089] like Figure 4 or Figure 5 As shown, the cylindrical vibration damping device 10, with the above structure, is installed on the mounting member 60 by inserting the outer cylinder member 14 into the mounting hole 62 provided in the mounting member 60, such as the vehicle body. The diameter of the mounting hole 62 is larger than the outer diameter of the cylindrical portion 20 of the outer cylinder member 14, and smaller than the maximum outer diameter of the at least circumferential rubber 40 of the press-in rubber 38. Moreover, by inserting the cylindrical portion 20 of the outer cylinder member 14 into the mounting hole 62, the press-in rubber 38 is radially compressed between the cylindrical portion 20 of the outer cylinder member 14 and the inner circumferential surface of the mounting hole 62, and the outer cylinder member 14 is fixedly installed in the mounting hole 62 by utilizing the elasticity of the press-in rubber 38. In this way, the outer cylinder member 14 is installed in the mounting hole 62 by rubber pressing based on the press-in rubber 38, and therefore, the fixing force fixed to the mounting hole 62 is set according to the spring characteristics of the press-in rubber 38, the amount of compression deformation (radial interference), etc. Since the pressing reaction force acting on the outer cylinder component 14 is mitigated by the pressing rubber 38, even if the outer cylinder component 14 is made of synthetic resin, it can suppress the plastic deformation (aging) of the outer cylinder component 14 caused by the continuous action of the pressing reaction force, so that the problem of reduced fixing force (anti-detachment resistance) due to the aging of the outer cylinder component 14 is not likely to occur.

[0090] The flange portion 22 of the outer cylinder member 14 abuts against the open end face 64 of the mounting hole 62. This defines the axial position of the outer cylinder member 14 relative to the mounting hole 62. The overlapping surface of the flange portion 22 relative to the open end face 64 of the mounting hole 62 is formed as an exposed abutment surface 46 not covered by the pressed-in rubber 38, and the flange portion 22 overlaps with the open end face 64 of the mounting hole 62 in a direct abutment state. Therefore, the rubber is not compressed between the overlapping surfaces of the abutment surface 46 of the flange portion 22 and the open end face 64 of the mounting hole 62, preventing the outer cylinder member 14 from detaching from the mounting hole 62 due to the elasticity of the rubber, thereby enabling high-precision axial positioning of the outer cylinder member 14 relative to the mounting hole 62.

[0091] The outer peripheral protrusion 54 of the connecting rubber 52 disposed between the flange portions 22 in the circumferential direction does not protrude relative to the abutment surface 46 of the flange portion 22, and is in contact with or spaced apart from the opening end face 64 of the mounting hole 62 without being pressed. In this embodiment, as Figure 4 As shown in the magnified view, the outer peripheral protrusion 54 does not come into strong contact with the opening end face 64 of the mounting hole 62.

[0092] By pressing the pressing surface 48 of the flange 22 on the side opposite to the abutment surface 46 using a clamp, the outer cylinder member 14, to which the press-in rubber 38 is fixed, can be pressed into the assembly hole 62. In this case, the pressing surface 48 of the flange 22 is not covered by rubber and is exposed, so the force acting on the outer cylinder member 14 from the clamp will not be weakened due to the deformation of the rubber, and the pressing operation can be performed efficiently by applying force.

[0093] The end of the outer cylinder member 14 on the press-in top side is formed as a continuous press-in top portion 50 covering the entire circumference, without notches or the like. Therefore, in the initial pressing stage when only the press-in top portion 50 is inserted into the assembly hole 62, it is possible to prevent the outer cylinder member 14 from tilting relative to the mounting member 60, and the outer cylinder member 14 and the mounting member 60 can be positioned in the appropriate direction.

[0094] Furthermore, the outer peripheral surface of the press-in tip 50 of the outer cylinder component 14 is not covered by rubber and is exposed to the outside. Therefore, in the initial pressing stage, the press-in tip 50, whose outer diameter is smaller than the inner diameter of the assembly hole 62, can be easily inserted into the assembly hole 62, and the frictional resistance in the initial pressing stage is suppressed.

[0095] In this embodiment, the press-in rubber 38 is configured as a combination of multiple circumferential rubbers 40 and multiple axial rubbers 42. This allows for adjustment of the spring constant when the press-in rubber 38 is compressed radially between the cylindrical portion 20 of the outer cylinder member 14 and the inner circumferential surface of the mounting hole 62. It also reduces the force required during pressing while ensuring the necessary fixing force based on rubber pressing. In particular, since the maximum protrusion height of the circumferential rubbers 40 is greater than the maximum protrusion height of the axial rubbers 42, it effectively resists the outer cylinder member 14 from axially detaching from the mounting hole 62. Furthermore, the tip portion of the circumferential rubber 40 in the pressing direction is formed as a tapered portion 44 with a diameter decreasing towards the pressing tip, thus suppressing resistance during pressing while ensuring resistance against detachment.

[0096] The embodiments of the present invention have been described in detail above, but the present invention is not limited to this specific description. For example, the notch 24 may be provided only on the outer periphery of either rubber arm 30. In addition, the notch 24 may not need to be positioned circumferentially with the rubber arm 30; for example, it may be provided on the outer periphery of the stop rubber 32. In this case, the connecting rubber 52 provided on the notch 24 may be provided, for example, as continuous with the outer periphery of the stop rubber 32.

[0097] In the main body rubber elastomer 16, a pair of recessed holes 28 and a pair of rubber arms 30 extending between these recessed holes 28 are not necessary. For example, it is possible to form only one recessed hole 28, or to use a main body rubber elastomer that connects the inner shaft member 12 and the outer cylinder member 14 around the entire circumference without recessed holes 28.

[0098] The pressed-in rubber 38 does not necessarily have to be formed as shown in the above embodiment, which is a combination of circumferential rubber 40 and axial rubber 42. For example, it can be a cylindrical shape that extends throughout the circumference with a substantially constant cross-section.

[0099] The injection gate mark 58 can be either the inner circumferential injection gate mark 58a or the outer circumferential injection gate mark 58b, for example, it can be composed only of the inner circumferential injection gate mark 58a. Alternatively, the inner circumferential injection gate mark 58a and the outer circumferential injection gate mark 58b can be located at different positions in the circumferential direction, for example, either one can be located on the outer circumference of the stop rubber 32. Furthermore, the injection gate mark 58 can also include injection gate marks other than the inner circumferential injection gate mark 58a and the outer circumferential injection gate mark 58b. The position and number of injection gates can be appropriately changed considering the shape of the rubber to be molded and the filling properties of the rubber material. Alternatively, the inner circumferential injection gate mark 58a and the outer circumferential injection gate mark 58b in the above embodiment can be connected radially to form a single injection gate mark.

[0100] The present invention can also be applied to fluid-sealed cylindrical vibration damping devices having a fluid chamber containing an incompressible fluid.

Claims

1. A cylindrical vibration damping device (10) having a structure in which an inner shaft member (12) and an outer cylinder member (14) made of synthetic resin are connected by a main rubber elastomer (16), wherein, The outer cylinder component (14) has a structure in which a cylindrical portion (20) extends axially from the inner peripheral end of the annular flange portion (22). A press-fit rubber (38) is fixed to the outer peripheral surface of the cylindrical portion (20), and the axial surface of the protruding side of the cylindrical portion (20) in the flange portion (22) is exposed and not covered by the press-fit rubber (38). A radially penetrating notch (24) is provided at the axial end of the outer cylinder member (14) containing the flange portion (22). A connecting rubber (52) is provided in the notch (24) to connect the main rubber elastomer (16) and the press-in rubber (38). The connecting rubber (52) is disposed in the notch (24) without protruding axially outward relative to the flange (22).

2. The cylindrical vibration damping device (10) according to claim 1, wherein, In the main body rubber elastomer (16), a pair of recessed holes (28) are formed on both radial sides of the inner shaft member (12). A pair of rubber arms (30) are provided on the main rubber elastomer (16). The pair of rubber arms (30) extend radially between the pair of recessed holes (28) in the circumferential direction and connect the inner shaft member (12) and the outer cylinder member (14) to each other. The connecting rubber (52) is disposed on the outer periphery of each of the rubber arms (30).

3. The cylindrical vibration damping device (10) according to claim 1, wherein, In the connecting rubber (52), a peripheral protrusion (54) is provided between the notch (24) and the circumferential end of the flange (22), which protrudes outward from the periphery of the press-in rubber (38). An injection gate mark (58) for the rubber material used in the molding of the connecting rubber (52) is formed on the outer peripheral protrusion (54).

4. The cylindrical vibration damping device (10) according to claim 1, wherein, The axial end of the cylindrical portion (20) opposite to the flange portion (22) is formed as a continuous cylindrical press-in tip portion (50) covering the entire circumference, the outer peripheral surface of which is not covered by the press-in rubber (38) and is exposed.

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