Vibration isolation device

Abstract

To provide a vibration isolation device with a novel structure that can stably hold a stopper member as a different body in an accommodation recessed place even before being mounted on a vehicle etc., while suppressing an influence of the stopper member on vibration isolation performance.SOLUTION: A vibration isolation device 10 which has a stopper member 14 as a different body accommodated in an axially-open accommodation recessed place 34 is provided with a fall stopping part 42 which protrudes to an inner circumference at an opening part of the accommodation recessed place 34. A stopper member 14 having a substantially quadrangular outer shape is provided with lip-like parts 56 which protrude from four corner parts to an outer circumference, and the lip-like parts 56 are positioned in the accommodation recessed place 34 inside the fall stopping part 42, and overlap the fall stopping part 42 when axially projected. A rod insertion hole 46 is formed axially through the stopper member 14, and a pair of opposite-side parts 52, 52 of an outer peripheral surface of the stopper member 14 are elongated from an inner circumferential surface of the accommodation recessed place 34 to the inner circumference in a region where they spread to both outer sides of the rod insertion hole 46 between the lip-like parts 56, 56.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a vibration isolation device used for an engine mount of an automobile or the like, and particularly to a vibration isolation device provided with a separate stopper member that restricts the relative displacement amount in the direction perpendicular to the axis between a first mounting member and a second mounting member.

Background Art

[0002] Conventionally, a vibration isolation device is known as a kind of vibration isolation connecting body or vibration isolation support body that is interposed between members constituting a vibration transmission system and elastically connects those members to each other. As shown in, for example, Japanese Patent No. 5543047 (Patent Document 1), the vibration isolation device has a structure in which a first mounting member attached to one member constituting the vibration transmission system and a second mounting member attached to the other member constituting the vibration transmission system are elastically connected to each other by a main body rubber elastic body.

[0003] Further, a housing recess is formed on the inner peripheral side of the second mounting member, and a separate stopper member is disposed in the housing recess, and the relative displacement amount in the direction perpendicular to the axis between the first mounting member and the second mounting member is restricted by contact via the stopper member.

[0004] . By the way, in the vibration isolation device described in Patent Document 1, it is necessary to hold the stopper member in the housing recess without dropping out from the housing recess in the vibration isolation device alone before being mounted on a vehicle or the like. In Patent Document 1, an elastic tapered portion as a retaining portion that inclines inward toward the opening side is provided at the opening portion of the housing recess, and the stopper protrusion of the stopper member protruding to the outer periphery is inserted deeper than the elastic tapered portion and overlaps the elastic tapered portion in the axial projection. Thereby, the locking between the stopper protrusion and the elastic tapered portion prevents the stopper member from dropping out of the housing recess, and the stopper member is held in the housing recess.

[0005] However, in Patent Document 1, for example, as shown in Figures 2 and 3, the stopper projection of the stopper member may be in contact with the inner circumferential surface of the receiving recess. In this case, the stopper member affects the spring characteristics in the direction perpendicular to the axis (left-right direction in Figures 2 and 3), which is the longitudinal direction of the vehicle, causing the spring of the vibration damping device in the longitudinal direction of the vehicle to become stiffer. As a result, it was considered that this could adversely affect vibration damping performance, such as vibration isolation against idling vibrations. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 5543047 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem to be solved by the present invention is to provide a novel vibration isolation device that can control the influence of the stopper member on vibration isolation performance, while also being able to stably hold a separate stopper member in a housing recess even before mounting it on a vehicle or the like. [Means for solving the problem]

[0008] 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.

[0009] The first embodiment is a vibration damping device in which a first mounting member and a second mounting member are connected by a main body rubber elastic body, and a separate stopper member is housed in a housing recess that opens axially on the inner circumference of a cylindrical portion of the second mounting member, wherein a retaining portion is provided in the opening of the housing recess that protrudes inward, the outer shape of the stopper member is substantially rectangular, and the stopper member is provided with a lip-shaped portion that protrudes outward from the rectangular portion, the lip-shaped portion is located behind the retaining portion in the housing recess, and the lip-shaped portion overlaps the retaining portion in axial projection, the stopper member has a rod insertion hole formed through it in the axial direction through which a rod member fixed to the first mounting member is inserted, and a pair of opposite sides located on both sides perpendicular to the axis on the outer surface of the stopper member are spaced inward relative to the inner surface of the housing recess in a region that extends to both outside sides of the rod insertion hole between the lip-shaped portions.

[0010] In a vibration damping device constructed according to this embodiment, the lip-shaped portion located behind the retaining portion provided on the inner circumferential surface of the opening of the housing recess catches on the retaining portion in the axial direction, thereby preventing the stopper member with the lip-shaped portion from easily falling out of the housing recess. Therefore, in a standalone vibration damping device before it is installed in a vehicle or the like, the stopper member is held within the housing recess, making transportation and management of the vibration damping device easier.

[0011] The stopper member has a lip-shaped portion that protrudes from the square portion, overlapping with the retaining portion in the axial projection. The outer surface of the stopper member has a pair of opposite sides located on both sides perpendicular to the axis between the circumferential directions of the lip-shaped portion, which are separated from the inner surface of the receiving recess. As a result, in the direction perpendicular to the axis where the pair of opposite sides are located, the stopper member is less likely to affect the spring characteristics of the vibration damper, making it easier to achieve low spring characteristics in that direction. Moreover, since the pair of opposite sides of the stopper member and the inner surface of the receiving recess are separated from each other over a wide area that extends to both outer sides of the rod insertion hole, the reduction in spring in the direction perpendicular to the axis due to the separation between the pair of opposite sides and the inner surface of the receiving recess is effectively achieved.

[0012] The second embodiment is a vibration isolation device described in the first embodiment, wherein another pair of opposite side portions located between the circumferentially positioned pairs of opposite side portions on the outer circumferential surface of the stopper member abuts against the inner circumferential surface of the receiving recess.

[0013] According to the vibration isolation device constructed in this embodiment, low spring characteristics are achieved in two directions perpendicular to the axes that are substantially orthogonal to each other, due to the separation between the outer surface of the stopper member and the inner surface of the receiving recess, and high spring characteristics are achieved due to the contact between the outer surface of the stopper member and the inner surface of the receiving recess. Therefore, it is possible to set a large spring ratio in the two directions perpendicular to the axes, and a large degree of freedom in tuning the spring characteristics can be obtained.

[0014] A third embodiment is a vibration isolation device described in the first or second embodiment, wherein the curvature of the pair of opposite sides of the stopper member is smaller than the curvature of the portion of the inner circumferential surface of the receiving recess that is opposite to the pair of opposite sides.

[0015] According to the vibration isolation device constructed in accordance with this embodiment, for example, even if both the pair of opposite sides of the stopper member and the inner surface of the receiving recess are curved surfaces that are concave or convex toward the inner circumference, the difference in curvature allows the pair of opposite sides of the stopper member and the inner surface of the receiving recess to be separated from each other.

[0016] The fourth aspect is the vibration isolation device described in the third aspect, wherein the pair of opposite sides of the stopper member are planar, and the portion of the inner circumferential surface of the receiving recess that faces the pair of opposite sides is a curved surface that is concave toward the inner circumference.

[0017] According to the vibration isolation device constructed in accordance with this embodiment, the difference in shape between the pair of opposite sides of the stopper member and the inner surface of the receiving recess allows for more reliable separation between the pair of opposite sides and the inner surface of the receiving recess.

[0018] The fifth embodiment is a vibration isolation device described in any one of the first to fourth embodiments, wherein the pair of opposite sides of the stopper member do not have partial recesses formed in the circumferential direction of the stopper member.

[0019] According to the vibration isolation device constructed in accordance with this embodiment, the absence of partial recesses in the pair of opposite sides ensures a large effective area of ​​the stopper surface formed by the pair of opposite sides, resulting in excellent load-bearing capacity against stopper loads. Furthermore, the absence of abrupt changes in cross-sectional shape in the pair of opposite sides reduces the likelihood of crack formation due to stress concentration when a stopper load is applied.

[0020] The sixth embodiment is a vibration isolation device described in any one of the first to fifth embodiments, wherein the lip-shaped portion extends continuously in the axial direction.

[0021] According to the vibration isolation device constructed in accordance with this embodiment, the deformation rigidity of the lip-shaped portion against axial input can be set to be large while setting the spring in the protruding direction of the lip-shaped portion to be soft. Therefore, in a vibration isolation device equipped with a stopper member, it is possible to effectively prevent axial slippage while setting the spring characteristics in the direction perpendicular to the axis to be soft.

[0022] The seventh embodiment is a vibration isolation device described in any one of the first to sixth embodiments, wherein the overlap of the lip-shaped portion with respect to the wall of the receiving recess in the retaining portion in an axial view is within the range of 70 to 100% of the protruding height of the lip-shaped portion.

[0023] According to the vibration isolation device constructed in accordance with this embodiment, the lip-shaped portion can be easily inserted over the retaining portion to the inner side, while effectively preventing the stopper member from being pulled out of the recessed area by the lip-shaped portion contacting the retaining portion. [Effects of the Invention]

[0024] According to the present invention, in a vibration isolator provided with a separate stopper member, it is possible to stably hold the separate stopper member in the accommodation recess even before mounting to a vehicle or the like while controlling the influence of the stopper member on the vibration isolation performance.

Brief Description of the Drawings

[0025] [Figure 1] Plan view showing an engine mount as a first embodiment of the present invention [Figure 2] Bottom view of the engine mount shown in FIG. 1 [Figure 3] Cross-sectional view taken along line III-III of FIG. 1 [Figure 4] Cross-sectional view taken along line IV-IV of FIG. 1 [Figure 5] Perspective view of a mount body constituting the engine mount shown in FIG. 1 [Figure 6] Perspective view showing the mount body shown in FIG. 5 from another angle [Figure 7] Longitudinal sectional view of the mount body shown in FIG. 5, corresponding to the cross-section VII-VII of FIG. 8 [Figure 8] Bottom view of the mount body shown in FIG. 7 [Figure 9] Cross-sectional view taken along line IX-IX of FIG. 8 [Figure 10] Perspective view of a stopper rubber constituting the engine mount shown in FIG. 1 [Figure 11] Plan view showing an enlarged view of the stopper rubber of FIG. 10 [Figure 12] Front view showing an enlarged view of the stopper rubber of FIG. 10 [Figure 13] Right side view showing an enlarged view of the stopper rubber of FIG. 10 [Figure 14] Cross-sectional view taken along line XIV-XIV of FIG. 12 [Figure 15] View showing an enlarged view of part A of FIG. 2

Embodiments for Carrying Out the Invention

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0027] Figures 1 to 4 show an engine mount 10 for an automobile as a first embodiment of a vibration damping device structured according to the present invention. The engine mount 10 has a structure in which a stopper member 14 is attached to a mount body 12 which serves as the vibration damping device body. Furthermore, as shown in Figures 5 to 8, the mount body 12 has a structure in which a first mounting member 16 and a second mounting member 18 are connected by a main rubber elastic body 20. In the following description, as a general rule, the vertical direction refers to the vertical direction in Figure 3, which is the axis of the mount's center; the front-rear direction refers to the vertical direction in Figure 1; and the left-right direction refers to the left-right direction in Figure 1. Note that the directions of the engine mount 10 described above do not necessarily coincide with the directions of the vehicle on which the engine mount 10 is mounted.

[0028] The first mounting member 16 has a roughly square shape with rounded corners when viewed in the axial direction. It is a highly rigid member made of a plate material such as iron or aluminum alloy, with its inner and outer ends spreading out in a direction approximately perpendicular to the axis, and its intermediate portion perpendicular to the axis tapering upward toward the outer circumference. A circular bolt insertion hole 22 is formed in the central part of the first mounting member 16, penetrating vertically. The first mounting member 16 is attached to the power unit side by inserting a rod member 24, which is a member on the power unit side, through the bolt insertion hole 22 and fixing it with bolts, as shown in Figure 3, for example.

[0029] The second mounting member 18, like the first mounting member 16, is a highly rigid member made of metal or the like, and integrally comprises a cylindrical portion 26 extending axially with a roughly square cross-section whose corners are rounded into an arc shape, and a flange portion 28 that extends outward perpendicular to the axis from the upper end of the cylindrical portion 26. The flange portion 28 protrudes more significantly outward on both the left and right sides than on both the front and rear sides, and bolt holes 30 are formed through the large protruding left and right sides. The second mounting member 18 is attached to the vehicle body by overlapping the flange portion 28 with the mounting portion 32 of the vehicle body and fixing it with bolts using the bolt holes 30, 30.

[0030] The first mounting member 16 is positioned above the second mounting member 18 at a distance from it, and the first mounting member 16 and the second mounting member 18 are elastically connected by the main rubber elastic body 20. The main rubber elastic body 20 has a roughly truncated square pyramidal shape with rounded corners, and the end on the smaller diameter side is vulcanized and bonded to the lower surface of the first mounting member 16, while the end on the larger diameter side is vulcanized and bonded to the cylindrical portion 26 and flange portion 28 of the second mounting member 18. The main rubber elastic body 20 is formed as an integrally vulcanized molded product comprising the first mounting member 16 and the second mounting member 18.

[0031] The main rubber elastic body 20 has a recess that opens downward, which opens downward through the cylindrical portion 26 of the second mounting member 18. As a result, a roughly rectangular receiving recess 34 is formed on the inner circumference of the cylindrical portion 26, opening downward in the axial direction. The outer circumference of the upper bottom wall of the receiving recess 34 is made of the main rubber elastic body 20 alone and is deformable, while one of the first mounting member 16 and the second mounting member 18 is fixed to the inner circumference of the upper bottom wall and the surrounding wall, thereby restricting the deformation of the inner circumference of the upper bottom wall and the surrounding wall.

[0032] In this embodiment, the main rubber elastic body 20 is not fixed to the central portion of the first mounting member 16, and the bolt insertion hole 22 of the first mounting member 16 and its peripheral portion are exposed to the receiving recess 34 through the central hole of the main rubber elastic body 20. As a result, when the rod member 24 is inserted into the receiving recess 34 from below, the threaded tip portion is inserted into the bolt insertion hole 22 of the first mounting member 16, and a step provided below the portion inserted into the bolt insertion hole 22 abuts against the peripheral edge of the bolt insertion hole 22 in the first mounting member 16 from below. Then, when a nut 36 is screwed onto the tip portion, the first mounting member 16 is sandwiched between the step of the rod member 24 and the nut 36, and the first mounting member 16 and the rod member 24 are fixed to each other in an axially positioned state.

[0033] The lower part of the main rubber elastic body 20 is a thin-walled cylindrical covering rubber layer 38 that covers the inner circumferential surface of the cylindrical portion 26 of the second mounting member 18 by forming a receiving recess 34. The covering rubber layer 38 is attached to the inner circumferential surface of the cylindrical portion 26 of the second mounting member 18 and constitutes the inner surface of the peripheral wall of the receiving recess 34. In this embodiment, the main rubber elastic body 20 also covers the outer circumferential surface and the lower surface of the cylindrical portion 26, and the portion covering the outer circumferential surface and the lower surface of the cylindrical portion 26 is integrally continuous with the covering rubber layer 38.

[0034] Guide ridges 40 are provided on the inner surface of the peripheral wall of the receiving recess 34, which is made of the main rubber elastic body 20. As shown in Figures 6 to 8, the guide ridges 40 extend axially from the open end of the receiving recess 34 in a substantially constant semicircular cross-section, and a pair of guide ridges 40 are formed on the inner surfaces of both the front and rear sides of the peripheral wall of the receiving recess 34, separated from each other in the circumferential direction (left-right direction). The pair of guide ridges 40, 40 located on the front side are formed separated from each other by a distance corresponding to the width dimension of the front guide projection 48 of the stopper member 14, which will be described later. Similarly, the pair of guide ridges 40, 40 located on the rear side are formed separated from each other by a distance corresponding to the width dimension of the rear guide projection 48 of the stopper member 14, which will be described later.

[0035] As shown in Figures 6 to 8, retaining portions 42 are provided at each of the four corners of the peripheral wall at the opening of the receiving recess 34. The retaining portions 42 are formed in a built-up manner at the four corners of the receiving recess 34 and protrude inward, and their inner surfaces are composed of tapered surfaces 44. As also shown in Figure 9, the tapered surface 44 is inclined inward toward the opening side, and the thickness dimension in the radial direction of the retaining portion 42, which has a tapered surface 44 on its inner surface, gradually increases toward the downward side, which is the opening side of the receiving recess 34. The inner diameter dimension at the four corners of the receiving recess 34 is smaller in the portion where the retaining portion 42 is formed than in the portion away from the retaining portion 42. Also, the thickness dimension of the peripheral wall at the four corners of the receiving recess 34 is larger in the portion where the retaining portion 42 is formed than in the portion away from the retaining portion 42.

[0036] The retaining portion 42, which has a tapered surface 44, has its upper bottom (inner) edge (base) of the receiving recess 34 positioned on the inner circumferential surface of the cylindrical portion 26 of the second mounting member 18, while the opening edge (tip) of the receiving recess 34 extends axially outward (downward) beyond the cylindrical portion 26. As a result, the base portion of the retaining portion 42 is restrained by the cylindrical portion 26, limiting its elastic deformation toward the outer circumference, while the tip portion is allowed to undergo elastic deformation toward the outer circumference.

[0037] A separate stopper member 14 is attached to the mount body 12. As shown in Figures 10 to 14, the stopper member 14 is integrally formed from a rubber elastic material and has a roughly bottomed rectangular tubular shape in the opposite direction. The stopper member 14 has a rod insertion hole 46 that penetrates vertically through the upper bottom wall, and the rod member 24 can be inserted into the rod insertion hole 46. The stopper member 14 has a cylindrical portion 47 that protrudes upward, and the rod insertion hole 46 is configured to include the lumen of the cylindrical portion 47. It is preferable that the stopper member be formed from an elastic material such as rubber or elastomer, but for example, a reinforcing material made of metal or a hard synthetic resin may be embedded inside the elastic material, or the entire stopper member may be made of a hard material.

[0038] The stopper member 14 is provided with a pair of guide projections 48, 48. The guide projections 48 are provided on both the front and rear sides of the stopper member 14 and are continuous in the axial direction with a predetermined width in the circumferential direction (left-right direction). The upper end surface of the guide projection 48 has a tapered shape that slopes downward toward the front and rear outward. The front and rear outer surfaces of the guide projection 48 are planar in shape that spreads substantially perpendicular to the front-rear direction. The guide projections 48, 48 constitute a pair of opposite sides on the outer circumferential surface of the stopper member 14.

[0039] The upper part of the stopper member 14 has stopper projections 50, 50 that protrude to the left and right sides. The upper surface of the stopper projection 50 is an inclined surface that slopes downward toward the projection tip, and the lower surface is an inclined surface that slopes upward toward the projection tip, and it has a tapered shape that narrows in the vertical direction toward the projection tip. The projection tip of the stopper projection 50 has a planar intermediate tip surface 52 that spreads out substantially perpendicular to the left and right directions. The intermediate tip surface 52 constitutes the opposite side portions located on both the left and right sides of the outer peripheral surface of the upper part of the stopper member 14. The intermediate tip surface 52 is substantially flat as a whole, and no partial recesses or protrusions are formed. At the base end of the stopper projection 50, a groove 54 is formed that opens to the upper surface and extends continuously along the entire length in the front-to-back direction. The groove 54 in this embodiment extends linearly with a substantially constant semicircular cross-section.

[0040] As shown in Figures 10, 11, and 14, lip-shaped portions 56 are formed protruding from both the front and rear ends of the tip surface of the stopper projection 50. The lip-shaped portions 56 protrude outward and are integrally formed with the upper square portion of the stopper member 14 composed of the stopper projections 50, 50. In this embodiment, the lip-shaped portions 56 extend continuously in the axial direction and are linear in the axial direction. It is desirable that the lip-shaped portions 56 have a tapered shape with a smaller cross-sectional area towards the protruding tip, and in this embodiment, the cross-sectional shape perpendicular to the axis is made to be approximately semicircular, so that it is narrower in the circumferential direction toward the protruding tip. In this embodiment, the lip-shaped portions 56 protrude outward on both the left and right sides, and the outer end faces in the front and rear directions do not protrude outward relative to the outer end faces in the front and rear directions of the stopper projection 50. The upper surface of the lip-shaped portions 56 is continuous with the upper surface of the stopper projection 50 and is an inclined surface that slopes downward toward the left and right outward directions. The intermediate tip surface 52, which is the protruding tip surface of the stopper projection 50, is provided between the front-rear and rear-facing lip-shaped portions 56, 56 that protrude from both the front and rear ends of the stopper projection 50.

[0041] In this embodiment, the stopper member 14 has a roughly rectangular outer shape in an axial view, with the main body portion excluding the guide projection 48 and the stopper projection 50 having a pair of guide projections 48, 48 on opposite sides in the longitudinal direction, and a pair of stopper projections 50, 50 on opposite sides in the short direction. The protrusion dimension of the stopper projection 50 is larger than that of the guide projection 48, and the stopper member 14 is thicker in the left-right direction where the stopper projection 50 is provided than in the front-rear direction where the guide projection 48 is provided.

[0042] Furthermore, notches 58 that open downwards are formed at the lower ends of each corner of the main body portion of the stopper member 14. The formation of the notches 58 reduces strain and blocks stress transmission in the lower part of the thin-walled stopper member 14. The inner surface of the notches 58 in this embodiment is a smooth curved surface, so that stress concentration on the inner surface of the notches 58 is mitigated when the stopper member 14 deforms.

[0043] The stopper member 14, with this structure, is inserted into the housing recess 34 of the mount body 12 from below and housed there. The stopper member 14 has a guide projection 48 which is inserted between guide ridges 40, 40 that protrude from the inner circumferential surface of the housing recess 34. This defines the left-right position of the stopper member 14, and it is also guided axially by the guide ridges 40, 40, thus facilitating proper insertion into the housing recess 34. As shown in Figures 2 and 4, the guide projection 48 of the stopper member 14 is overlapped with the inner surface of the circumferential wall of the housing recess 34 with virtually no gap between adjacent guide ridges 40, 40 in the left-right direction, and preferably abuts against the inner surface of the circumferential wall of the housing recess 34.

[0044] Each lip-shaped portion 56 provided at the corners of the stopper member 14 overcomes each retaining portion 42 provided at the four corners of the opening of the housing recess 34, and is located further back in the housing recess 34 than the retaining portion 42, so that the stopper protrusions 50, 50 are housed in the housing recess 34 further back than the retaining portion 42. As a result, as shown in Figures 2 and 15, the lip-shaped portion 56 overlaps the retaining portion 42 in the axial projection. The lip-shaped portion 56 may overlap the retaining portion 42 in its entirety in the axial direction, or it may overlap it partially in the axial direction. Preferably, the overlap amount h (see Figure 15) of the lip-shaped portion 56 with respect to the retaining portion 42 in the axial view is in the range of 70 to 100% of the maximum protrusion height H (see Figure 15) of the lip-shaped portion 56, and more preferably in the range of 80 to 90%. In Figure 15, the boundary between the stopper projection 50 and the lip-shaped portion 56 is virtually shown by a dashed line. As shown in Figure 15, the stopper projection 50 is located on the inner circumference side without overlapping the retaining portion 42 in the axial direction, while only the lip-shaped portion 56 overlaps the retaining portion 42 in the axial direction.

[0045] In this embodiment, the upper surface of the lip-shaped portion 56 is composed of an inclined surface that is continuous with the upper surface of the stopper projection 50. Therefore, when inserting the stopper member 14 into the receiving recess 34, the lip-shaped portion 56 can easily overcome the retaining portion 42 which has a tapered surface 44.

[0046] The stopper projection 50, which is inserted further inward than the retaining portion 42 in the receiving recess 34, has an intermediate tip surface 52 between the lip-shaped portions 56, 56 provided at both the front and rear ends, which is spaced inward and to the left and right relative to the inner circumferential surface of the receiving recess 34. In addition, both the front and rear sides of the stopper projection 50 are spaced inward and to the front and rear relative to the inner circumferential surface of the receiving recess 34. The intermediate tip surface 52 located between the lip-shaped portions 56 is spaced inward and to the left and right relative to the inner circumferential surface of the receiving recess 34 in the region that extends to the front and rear outer sides of the rod insertion hole 46. In short, as shown in Figure 2, the front-to-rear width dimension W of the region in which the intermediate tip surface 52 is spaced inward and to the left and right relative to the inner circumferential surface of the receiving recess 34 is larger than the front-to-rear diameter dimension R of the rod insertion hole 46.

[0047] The protruding tip of the lip-shaped portion 56 may or may not be in contact with the inner circumferential surface of the housing recess 34 beyond the retaining portion 42. If the protruding tip of the lip-shaped portion 56 is in contact with the inner circumferential surface of the housing recess 34, the position of the stopper member 14 in the direction perpendicular to the axis relative to the mount body 12 can be defined more stably. If the protruding tip of the lip-shaped portion 56 is separated from the inner circumferential surface of the housing recess 34, the influence of the stopper member 14 on the spring in the left-right direction, which will be described later, is further reduced, making it easier to achieve softer spring characteristics. In this embodiment, beyond the retaining portion 42, the lip-shaped portion 56 is separated inward from the inner circumferential surface of the housing recess 34, and the entire stopper projection 50, including the lip-shaped portion 56 and the front and rear sides, is separated from the inner circumferential surface of the housing recess 34.

[0048] The engine mount 10, which is composed of a mount body 12 and a separate stopper member 14, needs to be prevented from the stopper member 14 coming loose and falling out of the housing recess 34 of the mount body 12 when it is in a standalone state before being installed on a vehicle. In this case, the lip-shaped portion 56 of the stopper member 14 overlaps axially with the retaining portion 42 provided in the opening of the housing recess 34, so the axial locking of the lip-shaped portion 56 with the retaining portion 42 prevents the stopper member 14 from coming loose from the housing recess 34. Therefore, the mount body 12 and the stopper member 14 can be handled as a single unit, making storage and transportation of the engine mount 10 easier.

[0049] In the engine mount 10, the retaining structure that prevents the stopper member 14 from falling out of the mount body 12 is provided at the four corners of the stopper member 14 and the housing recess 34. This allows for a stable retaining effect without making the insertion of the stopper member 14 into the housing recess 34 excessively difficult, compared to a case where the retaining structure is provided around the entire circumference by locking in the axial direction.

[0050] The overlap h of the lip-shaped portion 56 with respect to the retaining portion 42 in an axial view is set to be within the range of 70-100% of the maximum protrusion height H of the lip-shaped portion 56. This makes it easier for the lip-shaped portion 56 to overcome the retaining portion 42 when inserting the stopper member 14 into the housing recess 34 and assembling it to the mount body 12, and effectively prevents the stopper member 14 from being pulled out of the housing recess 34 due to contact between the lip-shaped portion 56 and the retaining portion 42.

[0051] When the engine mount 10 is mounted on a vehicle, if a large load is applied in the lateral direction (front-to-back direction of the vehicle), the stopper projection 50 of the stopper member 14 abuts against the peripheral wall of the housing recess 34 of the mount body 12, thereby exhibiting a stopper action that limits the relative displacement of the first mounting member 16 and the second mounting member 18 in the lateral direction. This prevents excessive deformation of the main rubber elastic body 20 that connects the first mounting member 16 and the second mounting member 18, thereby improving the durability of the main rubber elastic body 20. Large loads in the lateral direction can be applied to the engine mount 10, for example, by sudden acceleration and deceleration of the vehicle.

[0052] The stopper projection 50 preferentially contacts the circumferential wall of the housing recess 34 at the lip-shaped portions 56 that protrude outward to the left and right. Subsequently, as the amount of compressive deformation of the lip-shaped portions 56 becomes sufficiently large, the intermediate tip surface 52 of the stopper projection 50 contacts the circumferential wall of the housing recess 34 between the lip-shaped portions 56, 56. In this way, the stopper projection 50 contacts the circumferential wall of the housing recess 34 in stages at the portion where the lip-shaped portions 56 are formed and the portion that is not attached to the lip-shaped portions 56. This reduces the impact caused by the contact between the stopper projection 50 and the circumferential wall of the housing recess 34, thereby minimizing the impact on ride comfort and other factors.

[0053] The front and rear sides of the stopper projection 50 are separated inward and inward from the inner circumferential surface of the receiving recess 34, and are free surfaces not constrained by the inner circumferential surface of the receiving recess 34. Therefore, when the left and right ends of the stopper projection 50 abut against the circumferential wall of the receiving recess 34 and the stopper projection 50 is compressed in the left-right direction, the stopper projection 50 is allowed to bulge outward on its front and rear sides, resulting in relatively soft spring characteristics.

[0054] On the other hand, when a large load is applied to the engine mount 10 mounted on the vehicle in the longitudinal direction (left-right direction of the vehicle), the guide projection 48 of the stopper member 14 is pressed against the peripheral wall of the housing recess 34 of the mount body 12 and compressed, thereby exerting a stopper action that limits the relative displacement of the first mounting member 16 and the second mounting member 18 in the longitudinal direction. This prevents excessive deformation of the main rubber elastic body 20 connecting the first mounting member 16 and the second mounting member 18, thereby improving the durability of the main rubber elastic body 20. In this embodiment, since the guide projection 48 is in contact with the inner peripheral surface of the housing recess 34 in advance, the stopper action by compression of the guide projection 48 is exerted quickly.

[0055] Furthermore, when small-amplitude vibrations such as idling vibrations are input to the engine mount 10 in the lateral direction, the vibration damping effect (vibration isolation effect) due to the low-movement spring characteristics is effectively exerted. Specifically, the intermediate tip surface 52 of the stopper projection 50 of the stopper member 14 is spaced apart in the lateral direction from the peripheral wall of the housing recess 34 between the front and rear lip-shaped portions 56, 56 provided at both the front and rear ends. Therefore, when small-amplitude vibrations are input, the influence of the stopper member 14 on the lateral spring characteristics of the engine mount 10 is reduced, making it easier to achieve low-movement spring characteristics in the lateral direction of the engine mount 10.

[0056] In this embodiment, the intermediate tip surface 52, located between the front and rear lip-shaped portions 56, 56, is separated inward and to the left and right from the inner circumferential surface of the housing recess 34 in a region that extends to the outer sides of both the front and rear of the rod insertion hole 46. In this way, a wide area of ​​separation between the stopper projection 50 and the inner circumferential surface of the housing recess 34 is secured in the circumferential direction, so that the stopper member 14 is less likely to affect the spring characteristics of the engine mount 10 when small amplitude vibrations are input in the left and right direction. In this embodiment, since the entire stopper projection 50, including the lip-shaped portions 56 and the front and rear side surfaces, is separated inward from the inner circumferential surface of the housing recess 34, the spring of the stopper member 14 is less likely to affect the spring when small amplitude vibrations are input in the left and right direction, and soft spring characteristics are achieved.

[0057] The gap between the intermediate tip surface 52 of the stopper projection 50 and the inner circumferential surface of the receiving recess 34 is set by making the curvature of the intermediate tip surface 52 of the stopper projection 50 smaller than the curvature of the portion of the inner circumferential surface of the receiving recess 34 that is in opposition to the intermediate tip surface 52. In particular, in this embodiment, the intermediate tip surface 52 is substantially planar, and the portion of the inner circumferential surface of the receiving recess 34 that is in opposition to the intermediate tip surface 52 is a circumferentially curved surface that is concave inward. As a result, the difference in shape between the intermediate tip surface 52 and the inner circumferential surface of the receiving recess 34 allows the intermediate tip surface 52 to be easily positioned to the left and right and inward relative to the inner circumferential surface of the receiving recess 34.

[0058] In this embodiment, since the guide projections 48, 48 of the stopper member 14 of the engine mount 10 are in close proximity to or in contact with the inner surface of the peripheral wall of the housing recess 34, the stopper member 14 easily influences the spring characteristics of the engine mount 10 even when small amplitude vibrations are input in the longitudinal direction. Therefore, it is possible to set a stiff spring characteristic in the longitudinal direction of the engine mount 10 by utilizing the spring of the stopper member 14, thereby achieving, for example, improved vehicle handling stability. In particular, in this embodiment, since the protruding tip portion of the guide projection 48 is inserted in contact with the left and right guide ribs 40, 40, the deformation of the protruding tip portion of the guide projection 48 is constrained by the guide ribs 40, 40, making it easier to obtain a relatively stiff spring characteristic.

[0059] In Figure 3, to make it easier to understand how the engine mount 10 is attached to the vehicle, the rod member 24 on the power unit side and the mounting portion 32 on the vehicle body side are virtually shown with dashed lines relative to the engine mount 10 in its standalone state. However, in the actual vehicle mounting state, the support load borne by the power unit acts downward, causing the first mounting member 16 and the stopper member 14 to be displaced downward relative to the second mounting member 18. Therefore, in the vehicle mounting state of the engine mount 10, the stopper protrusions 50, 50 of the stopper member 14 are positioned opposite the cylindrical portion 26 of the second mounting member 18 in the left-right direction, and the portion where a stopper load acts in the left-right direction due to the contact of the stopper protrusions 50, 50 is composed of the reinforced portion of the circumferential wall of the housing recess 34 by the cylindrical portion 26. Thus, deformation of the circumferential wall of the housing recess 34 due to the action of the stopper load is reduced.

[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 retaining portion 42 does not necessarily have to be formed only at the four corners, but may be formed in the portion corresponding to the lip-shaped portion 56. Specifically, for example, the retaining portion 42 may be provided in a continuous annular shape around the entire circumference.

[0061] The retaining portion 42 is provided by making the covering rubber layer 38 that constitutes the inner surface of the peripheral wall of the receiving recess 34 thicker toward the opening side of the receiving recess 34, as in the embodiment described above. Alternatively, it can be provided by making the lower part of the cylindrical portion 26 tapered so that its diameter decreases toward the downward side. The inner circumferential surface of the retaining portion 42 is preferably a tapered surface 44 that inclins toward the inner circumference toward the opening side of the receiving recess 34, but it may also be composed of a surface that extends without inclination in the axial direction, or a reverse tapered surface that inclins toward the outer circumference toward the opening side of the receiving recess 34.

[0062] The lip-shaped portion 56 does not necessarily have to be formed only on the upper part of the stopper member 14; for example, it may be formed along the entire axial length of the outer circumferential surface of the stopper member 14. In this case, the entire axial length of the stopper member 14 is inserted into the receiving recess 34 beyond the retaining portion 42, so that the lip-shaped portion 56 is positioned beyond the retaining portion 42.

[0063] The lip-shaped portion 56 may, for example, be formed to protrude diagonally from the stopper member 14, which has a rectangular outer shape, or it may protrude in the front-rear direction from the rectangular portion of the stopper member 14. The cross-sectional shape of the lip-shaped portion 56 is not particularly limited. The lip-shaped portion 56 does not necessarily have to be axially extending, and may be, for example, a spot-like projection.

[0064] The intermediate tip surface 52 located between the lip-shaped portions 56, 56 is not limited to a flat surface, but may be, for example, a curved surface that is concave or convex toward the outer circumference. Also, the inner circumferential surface of the receiving recess 34 facing the intermediate tip surface 52 is not limited to a curved surface that is concave toward the inner circumference, but may be, for example, a flat surface or a curved surface that is convex toward the inner circumference. In either case, the intermediate tip surface 52 and the inner circumferential surface of the receiving recess 34 facing it are positioned opposite each other, separated by differences in curvature, shape, front-to-back diameter dimensions, etc., to an area that extends outward from the front-to-back of the rod insertion hole 46.

[0065] The receiving recess 34 is not limited to a rectangular shape when viewed in the axial direction; for example, it may be circular or a polygon other than a rectangle.

[0066] The scope of application of the present invention is not limited to engine mounts, but can also be applied to vibration damping devices used as subframe mounts, body mounts, differential mounts, etc. Furthermore, the present invention is not limited to vibration damping devices for automobiles, but can also be applied to vibration damping devices used in motorcycles, railway vehicles, industrial vehicles, etc. [Explanation of symbols]

[0067] 10. Engine mount (vibration damping device, first embodiment) 12 Mount body 14 Stopper member 16 First mounting member 18 Second mounting member 20 Main body rubber elastic body 22 Bolt insertion holes 24 Rod members 26 Cylindrical part 28 Flange section 30 bolt holes 32 Mounting part 34 Containment Depression 36 nuts 38. Covering rubber layer 40 Guide protrusions 42 Retaining part 44 Tapered surface 46 Rod insertion holes 47 Cylindrical part 48 Guide projection 50 Stopper protrusion 52 Intermediate tip surface 54 groove 56 Lip-shaped part 58 Notches

Claims

1. The first mounting member and the second mounting member are connected by the main body's rubber elastic material. In a vibration isolation device in which a separate stopper member is housed in a receiving recess that opens axially on the inner circumference of the cylindrical portion of the second mounting member, The opening of the aforementioned recess is provided with a retaining portion that protrudes inward, The stopper member has a roughly rectangular outer shape, and the stopper member is provided with a lip-shaped portion that protrudes from the rectangular portion toward the outer circumference. The lip-shaped portion is located further back than the retaining portion in the receiving recess, and the lip-shaped portion overlaps the retaining portion in axial projection, The stopper member has a rod insertion hole formed axially through which a rod member fixed to the first mounting member is inserted. A vibration isolation device in which a pair of opposite sides located on both sides perpendicular to the axis on the outer circumferential surface of the stopper member extend to the outer sides of the rod insertion hole between the lip-shaped parts, and are spaced inward relative to the inner circumferential surface of the receiving recess.

2. The vibration isolation device according to claim 1, wherein another pair of opposite side portions located between the circumferentially opposite side portions on the outer circumferential surface of the stopper member are in contact with the inner circumferential surface of the receiving recess.

3. The vibration isolation device according to claim 1 or 2, wherein the magnitude of curvature of the pair of opposite side portions in the stopper member is smaller than the magnitude of curvature of the portion on the inner circumferential surface of the receiving recess that is opposite to the pair of opposite side portions.

4. The pair of opposite sides of the stopper member are planar, The vibration isolation device according to claim 3, wherein the portion of the inner circumferential surface of the receiving recess that is opposite to the pair of opposite side portions is a curved surface that is concave toward the inner circumference.

5. The vibration damping device according to claim 1 or 2, wherein the pair of opposite sides of the stopper member have partial recesses formed in the circumferential direction of the stopper member.

6. The vibration isolation device according to claim 1 or 2, wherein the lip-shaped portion extends continuously in the axial direction.

7. The vibration isolation device according to claim 1 or 2, wherein the overlap of the lip-shaped portion with respect to the wall of the receiving recess in the retaining portion in an axial view is within the range of 70 to 100% of the protruding height of the lip-shaped portion.

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