JP7233331B2 - Cylindrical anti-vibration device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular vibration isolator applied to, for example, an engine mount of an automobile.

2. Description of the Related Art Cylindrical antivibration devices applied to automobile engine mounts, subframe mounts, and the like have been known. For example, in Japanese Patent Laying-Open No. 2018-071768 (Patent Document 1), an inner shaft member having a plate-shaped portion at its upper end and an outer cylindrical member having a widened portion at its upper end are elastically connected by a main rubber elastic body. An engine mount is disclosed having a structured structure.

JP 2018-071768 A

By the way, in a cylindrical vibration isolator having a conventional structure, a hollow is sometimes provided in the main rubber elastic body for the purpose of adjusting the spring characteristic or the like. For example, as described in Patent Document 1 and the like, a recess-shaped hollow hole that opens in one end face of the main rubber elastic body in the axial direction and extends in the circumferential direction is adopted.

However, when a hollow hole is provided as in Patent Document 1, it may be difficult to ensure durability. For example, when the input load is large, or when it is difficult to ensure the radial thickness of the main rubber elastic body due to the size set in consideration of the installation space of the cylindrical anti-vibration device, etc. In some cases, it has been difficult to achieve a high degree of compatibility between the realization of spring characteristics by holes and the assurance of durability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cylindrical vibration isolator with a novel structure that can achieve a degree of freedom in tuning spring characteristics and the like while sufficiently ensuring the durability of the main rubber elastic body.

Hereinafter, preferred embodiments for understanding the present invention will be described. can be recognized and employed as independently as possible, and can also be employed in combination with any of the components described in other aspects as appropriate. Accordingly, the present invention can be implemented in various alternatives without being limited to the embodiments described below.

A first aspect is a tubular type in which an inner shaft member having a plate-shaped portion at one end in the axial direction and an outer tubular member having a widened portion at one end in the axial direction are connected by a main rubber elastic body. In the anti-vibration device, the main rubber elastic body is provided with a hollow portion which is open at the other end surface in the axial direction and extends axially toward the plate-like portion on the outer peripheral surface of the inner shaft member. The inner shaft member is provided with a deformation control surface protruding on the outer peripheral surface, and the deformation control surface includes an overlap region extending along the inner surface of the hollow portion, and an overlapping region extending from the hollow region. A release area is provided that gradually separates from the inner surface of the hollow portion toward the opening side of the portion, and the contact area of the main rubber elastic body against the deformation control surface overlaps as the input load increases. It spreads from the area toward the release area.

According to the cylindrical vibration isolator constructed according to this mode, the size and position of the free surface of the main rubber elastic body and the rubber volume of the main rubber elastic body are controlled by providing the main rubber elastic body with the cavity. etc. can be appropriately set by the hollow portion to adjust the spring characteristics and the like, and excellent tuning flexibility can be ensured.

A deformation control surface protruding from the outer peripheral surface of the inner shaft member is provided, and when the main rubber elastic body elastically deforms, the inner surface of the hollow portion of the main rubber elastic body comes into contact with the deformation control surface, so that the hollow portion is deformed. The deformation mode or amount of inner surface can be controlled. Therefore, it is possible to suppress the deformation mode in which the strain is locally concentrated on the inner surface of the cavity. Concentration can be avoided and the durability of the main rubber elastic body can be improved.

The deformation control surface provided on the inner shaft member has an overlap region and a release region, and when the main rubber elastic body is elastically deformed and the hollow portion is deformed, the deformation control surface of the main rubber elastic body abuts against the deformation control surface. The contact area expands from the overlap area toward the release area as the input load and the amount of elastic deformation increase. As a result, when the amount of deformation of the main rubber elastic body is small, the restraint area of the main rubber elastic body by the deformation control surface is narrowed, and the large free surface of the main rubber elastic body realizes soft spring characteristics with a small spring constant. can do. As the amount of deformation of the main rubber elastic body increases, the area of contact with the deformation control surface of the main rubber elastic body expands to the release area, and the area where the main rubber elastic body is restrained by the deformation control surface widens. It is also possible to non-linearly improve the deformation rigidity of the rubber elastic body.

A second aspect is the cylindrical vibration isolator according to the first aspect, wherein the deformation control surface is a curved surface in which a plurality of steps with stepped protrusion heights are connected smoothly in the axial direction. It is what is done.

According to the cylindrical vibration damping device constructed according to this mode, the area of contact of the main rubber elastic body with the deformation control surface increases stepwise as the input load increases. Soft spring characteristics when the amount of deformation is small and dispersion of strain when the amount of deformation of the main rubber elastic body is large are effectively realized.

According to a third aspect, in the cylindrical vibration damping device according to the first or second aspect, the deformation control surface is constituted by a large-diameter portion integrally formed with the inner shaft member.

According to the cylindrical vibration damping device constructed according to this mode, the inner shaft member provided with the deformation control surface is realized by a simple structure with a small number of parts.

According to a fourth aspect, in the cylindrical vibration damping device according to the first or second aspect, the deformation control surface is formed by a separate member that is externally fitted and fixed to the inner shaft member.

According to the cylindrical vibration damping device constructed according to this aspect, for example, it is possible to provide the deformation control surface by post-attaching a separate member to the inner shaft member that is vulcanized and bonded during molding of the main rubber elastic body. become.

A fifth aspect is the cylindrical vibration damping device according to any one of the first to fourth aspects, wherein the stopper projection projecting from the inner shaft member into the cavity extends to the depth of the cavity. It is provided in the middle part of the direction.

According to the cylindrical vibration damping device constructed according to this aspect, a stopper mechanism is realized that buffers and limits the amount of relative displacement between the inner shaft member and the outer cylindrical member in the direction perpendicular to the axis by using the hollow portion. can be done.

Moreover, since the stopper protrusion abuts against the inner surface of the hollow portion, the deformation of the inner surface of the hollow portion is restrained even in a portion outside the deformation control surface. By suppressing the amount, the durability of the main rubber elastic body is further improved.

A sixth aspect is the cylindrical vibration isolator according to any one of the first to fifth aspects, wherein the outer peripheral surface of the main rubber elastic body located on the outer peripheral side of the overlap region is the outer tube. It is a free surface that is not fixed to a member.

According to the cylindrical vibration isolator constructed according to this aspect, the outer peripheral surface of the main rubber elastic body located on the outer peripheral side of the overlap region is a free surface, so that the main rubber elastic body has a high degree of freedom of deformation. In addition, even in a state in which the inner surface of the hollow portion of the main rubber elastic body is restrained from being deformed by the overlapping region, for example, it is possible to easily avoid a significant increase in spring.

A seventh aspect is the cylindrical vibration damping device according to any one of the first to sixth aspects, wherein the deformation control surface is continuous over the entire circumference in the circumferential direction, and the deformation control surface The overlap region extends along the inner surface of the cavity over the entire circumference.

According to the cylindrical vibration damping device constructed according to this aspect, the local concentration of distortion of the main rubber elastic body due to the input is avoided over the entire circumference, and the durability of the main rubber elastic body is improved.

According to an eighth aspect, in the cylindrical vibration isolator according to any one of the first to seventh aspects, the cavity extends axially with a substantially constant inner diameter.

According to the cylindrical vibration damping device constructed according to this aspect, when the main rubber elastic body is elastically deformed, strain concentration is less likely to occur on the inner surface of the hollow portion.

According to the present invention, in a tubular vibration isolator, it is possible to achieve a degree of freedom in tuning spring characteristics and the like while sufficiently ensuring the durability of the main rubber elastic body.

A sectional view showing an engine mount as a first embodiment of the present invention. Cross-sectional view of an integrally vulcanized molded product that constitutes the engine mount shown in FIG. FIG. 2 is a sectional view showing a state in which an axial compressive load acts on the main rubber elastic body of the engine mount shown in FIG. 1; Sectional view showing an engine mount as a second embodiment of the present invention Sectional view of an integrally vulcanized molded product that constitutes the engine mount shown in FIG. FIG. 5 is a cross-sectional view showing a state in which an axial compressive load acts on the main rubber elastic body of the engine mount shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an engine mount 10 for an automobile as a first embodiment of a cylindrical vibration damping device constructed according to the present invention. The engine mount 10 has a structure in which an inner shaft member 12 and an outer cylindrical member 14 are connected by a main rubber elastic body 16 . In the following description, the vertical direction refers to the vertical direction in FIG. 1, which is the central axis direction of the mount.

The inner shaft member 12 is made of metal, synthetic resin, or the like. The inner shaft member 12 has a structure in which an annular plate-shaped plate portion 18 is superimposed on the upper surface of a substantially cylindrical shaft body 20 that extends linearly in the vertical direction.

Like the inner shaft member 12, the outer cylindrical member 14 is made of metal, synthetic resin, or the like. The outer tubular member 14 has a thin, large-diameter, substantially cylindrical shape. The outer tubular member 14 is provided with a flared portion 22 whose diameter increases upward on the upper side of a tubular portion 21 that has a substantially constant diameter and extends linearly in the vertical direction. An inner flange portion 23 is provided on the lower side of the cylindrical portion 21 so as to protrude inward.

A plate-like portion 18 provided at the upper end portion of the inner shaft member 12 and the outer cylindrical member 14 are vertically separated and elastically connected by a main rubber elastic body 16 . The main rubber elastic body 16 has a cylindrical shape and has a hollow portion 24 in its radially central portion. The hollow portion 24 has an inner surface 26 that extends linearly in the vertical direction with a substantially constant inner diameter, and has an opening 28 on the lower surface of the main rubber elastic body 16 . The hollow portion 24 has an opening portion 28 at the lower end of the inner surface 26 that widens downward, and the upper end portion has a partially reduced diameter. The upper surface of the main rubber elastic body 16 is fixed to the lower surface of the plate-like portion 18 of the inner shaft member 12 , and the outer peripheral surface of the main rubber elastic body 16 is fixed to the inner peripheral surface of the outer cylindrical member 14 . . As shown in FIG. 2, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including a plate-like portion 18 and an outer tubular member 14. The plate-like portion 18 and the outer tubular member 14 are formed by the main rubber elastic body. It is vulcanized and bonded to the body 16 when the main rubber elastic body 16 is molded.

The upper portion 30 of the main rubber elastic body 16 is positioned vertically between the plate-like portion 18 of the inner shaft member 12 and the expanded portion 22 of the outer tubular member 14 , and the outer tubular member 14 is located on the outer peripheral surface 31 . Not fixed. As a result, the outer peripheral surface 31 of the upper portion 30 of the main rubber elastic body 16 is a free surface exposed to the outer periphery between the plate-like portion 18 and the expanded portion 22 . The exposed outer peripheral surface 31 of the upper portion 30 of the main rubber elastic body 16 has a cross-sectional shape that is concave toward the outer periphery.

The shaft main body 20 of the inner shaft member 12 is inserted into the cavity 24 of the main rubber elastic body 16 through an opening 28 on the side opposite to the fixing side of the plate-like portion 18 . Then, the upper surface of the shaft body 20 is abutted against and overlapped with the lower surface of the inner peripheral portion of the plate-like portion 18 that constitutes the integrally vulcanized product of the main rubber elastic body 16 . The lower end of the shaft body 20 protrudes downward from the opening 28 of the cavity 24 when the upper surface of the shaft body 20 abuts against the plate-like portion 18 .

The hollow portion 24 of the main rubber elastic body 16 axially extends from the opening 28 at the lower end toward the plate-like portion 18 on the outer peripheral surface of the shaft main body 20 of the inner shaft member 12 . A shaft body 20 of the inner shaft member 12 is inserted through the hollow portion 24 of the main rubber elastic body 16 and extends in the axial direction, and the outer peripheral surface of the shaft body 20 is separated from the inner surface 26 of the hollow portion 24 to the inner periphery. there is

A large-diameter portion 32 is formed integrally with the upper portion of the shaft body 20 inserted into the hollow portion 24 . The large-diameter portion 32 protrudes outward from the outer peripheral surface of the shaft body 20 toward the inner surface 26 of the hollow portion 24 and is positioned at the upper end of the hollow portion 24 . The outer peripheral surface of the large-diameter portion 32 is a smoothly continuous deformation control surface 34 . The deformation control surface 34 is a continuous curved surface with a substantially constant cross-sectional shape over the entire circumference. The deformation control surface 34 has an overlap region 36 at the top and a release region 38 at the bottom.

The overlapping region 36 has a substantially cylindrical surface and extends along the inner surface 26 of the hollow portion 24 over the entire circumference when the shaft body 20 is inserted into the hollow portion 24 . The overlap region 36 of this embodiment abuts the inner surface 26 of the cavity 24 . The overlapping region 36 may be in contact with the inner surface 26 of the hollow portion 24 in a 0-touch state in which the contact pressure is approximately 0, or may contact the inner surface 26 of the hollow portion 24 with a predetermined contact pressure greater than 0. It doesn't matter if it's pushed. Also, the overlap region 36 may have a gap partially or substantially entirely with respect to the inner surface 26 of the cavity 24 as long as it extends along the inner surface 26 of the cavity 24 .

A release region 38 is provided continuously below the overlapping region 36 . The release region 38 includes a first tapered surface 40 whose diameter gradually decreases downward from the overlapping region 36, a cylindrical surface 42 that widens with a substantially constant diameter below the first tapered surface 40, and a cylindrical surface. and a second tapered surface 44 whose diameter gradually decreases downward from 42 . In this way, the release area 38 includes a part in which the diameter dimension is substantially constant, but the diameter decreases downward as a whole. The release area 38 is thereby spaced inwardly relative to the inner surface 26 of the cavity 24 . The distance between the release area 38 and the inner surface 26 of the cavity 24 gradually increases from the overlap area 36 towards the opening 28 of the cavity 24 .

Since the release region 38 has a tubular surface 42 , the overlap region 36 and the tubular surface 42 of the release region 38 are provided in a stepped manner. As a result, the deformation control surface 34 has a stepped shape having a plurality of steps in which the heights of protrusion from the shaft body 20 are different in stages. The stepped overlapping region 36 and the cylindrical surface 42 are connected continuously in the axial direction in a smooth shape with no broken points by the first tapered surface 40, and the deformation control surface 34 is provided. It has a smooth curved surface.

A portion of the inner shaft member 12 below the release region 38 is separated from the inner surface 26 of the hollow portion 24 toward the inner periphery. Thus, between the inner shaft member 12 and the inner surface 26 of the hollow portion 24, an axially extending recess is annularly formed over the entire circumference.

1, a stopper protrusion 46 projecting into the hollow portion 24 is provided separately from the large diameter portion 32 on a portion of the inner shaft member 12 below the release region 38. can also The stopper protrusion 46 is provided, for example, at an intermediate portion in the depth direction (axial direction) of the cavity 24 so as to protrude from the outer peripheral surface of the shaft body 20 toward the inner surface 26 of the cavity 24 . The stopper protrusion 46 may be integrally formed with the inner shaft member 12 or may be a separate member from the inner shaft member 12 and fixed to the inner shaft member 12 .

If such a stopper protrusion 46 is provided at an intermediate portion in the depth direction of the hollow portion 24, the stopper protrusion 46 abuts against the outer cylindrical member 14 via the main rubber elastic body 16, thereby The amount of deformation of the elastic body 16 is limited to improve durability. Moreover, the stopper protrusion 46 abuts against the inner surface 26 of the hollow portion 24, restraining the deformation of the inner surface 26 of the hollow portion 24, thereby preventing concentration of strain on the inner surface 26 of the main rubber elastic body 16. Further improvement in durability of the main rubber elastic body 16 is achieved.

The large-diameter portion 32 has an overlapping region 36 located above the outer cylindrical member 14 , and the overlapping region 36 is arranged on the inner periphery of the upper portion 30 of the main rubber elastic body 16 . As a result, the outer peripheral surface of the portion of the main rubber elastic body 16 located on the outer peripheral side of the overlap region 36 is a free surface that is not fixed to the outer cylindrical member 14 . In this embodiment, the upper half portion of the release region 38 in the large diameter portion 32 is also arranged on the inner circumference of the upper portion 30 of the main rubber elastic body 16 .

The engine mount 10 has an inner shaft member 12 attached to a power unit (not shown) and an outer tubular member 14 attached to a vehicle body (not shown) so that the power unit and the vehicle body are coupled via the engine mount 10 for vibration isolation.

When the engine mount 10 is attached to the vehicle as described above, vibration is input between the inner shaft member 12 and the outer tubular member 14, and the inner shaft member 12 is displaced with respect to the outer tubular member 14. Body 16 is elastically deformed. The spring constant of the main rubber elastic body 16 is appropriately adjusted by providing the hollow portion 24 in the main rubber elastic body 16, thereby exhibiting excellent anti-vibration performance.

When a large vertical load is input between the inner shaft member 12 and the outer cylindrical member 14 and the main rubber elastic body 16 is largely elastically deformed, the durability of the main rubber elastic body 16 is ensured. That is, when the main rubber elastic body 16 is compressed between the plate-like portion 18 of the inner shaft member 12 and the expanding portion 22 and the inner flange-like portion 23 of the outer cylindrical member 14, as shown in FIG. The main rubber elastic body 16 is elastically deformed so as to expand on the inner surface 26 of the hollow portion 24 and the outer peripheral surface 31 of the upper portion 30 . The contact region where the inner surface 26 of the hollow portion 24 contacts the deformation control surface 34 of the large diameter portion 32 expands from the overlap region 36 toward the release region 38 , and the main rubber elastic body 16 is positioned on the deformation control surface 34 . It abuts not only the overlap region 36 but also the release region 38 . As a result, the deformation of the inner surface 26 of the hollow portion 24 is non-linearly controlled by the deformation control surface 34 of the large diameter portion 32, so that local concentration of strain on the inner surface 26 of the hollow portion 24 is prevented. The durability of the rubber elastic body 16 is improved.

The deformation control surface 34 of the large-diameter portion 32 includes an overlapping region 36 and a release region 38. When the main rubber elastic body 16 is elastically deformed, the main rubber elastic body 16 is in contact with the deformation control surface 34. spreads from the overlap region 36 toward the release region 38 as the input load increases. As a result, when the input load is small and the amount of deformation of the main rubber elastic body 16 is small, the restraint area of the main rubber elastic body 16 by the deformation control surface 34 is narrow, and soft spring characteristics with a small static spring constant are realized. can be done. When the input load is large and the amount of deformation of the main rubber elastic body 16 is large, the restraint area of the main rubber elastic body 16 by the deformation control surface 34 expands to the release area 38, and the main rubber elastic body 16 is locally deformed. strain concentration is avoided. In this way, when a small load that does not interfere with the durability of the main rubber elastic body 16 is input, excellent anti-vibration performance is realized due to the soft spring characteristics, and a large load that may damage the main rubber elastic body 16 is a concern. , the deformation of the main rubber elastic body 16 is restricted in a wider range by the deformation control surface 34, so that the durability of the main rubber elastic body 16 is ensured.

In the deformation control surface 34, the overlap region 36 and the cylindrical surface 42 of the release region 38 are provided in a plurality of steps with different protrusion heights. Furthermore, the tubular surface 42 of the overlap region 36 and the release region 38 are smoothly connected in the axial direction by the first tapered surface 40, and the deformation control surface 34 as a whole is a smoothly curved surface. As a result, the contact area of the main rubber elastic body 16 with the deformation control surface 34 increases stepwise as the input load increases. Therefore, soft spring characteristics when the amount of deformation of the main rubber elastic body 16 is small and dispersion of strain when the amount of deformation of the main rubber elastic body 16 is large are effectively realized. Moreover, since the deformation control surface 34 is a smoothly curved surface, stress concentration on the main rubber elastic body 16 due to the pressing of the deformation control surface 34 is less likely to occur.

The large diameter portion 32 forming the deformation control surface 34 is formed integrally with the shaft body 20 of the inner shaft member 12 . As a result, the inner shaft member 12 having the deformation control surface 34 can be realized with a simple structure with a small number of parts.

The outer peripheral surface 31 of the upper portion 30 of the main rubber elastic body 16 located on the outer peripheral side of the overlap region 36 is a free surface that is not fixed to the outer cylindrical member 14 . As a result, even when the deformation of the inner surface 26 of the hollow portion 24 in the main rubber elastic body 16 is restrained by the overlapping region 36, soft spring characteristics can be easily achieved.

The deformation control surface 34 is continuous over the entire circumference, and the overlapping region 36 of the deformation control surface 34 spreads along the inner surface 26 of the cavity 24 over the entire circumference. Therefore, the local concentration of distortion in the main rubber elastic body 16 is avoided over the entire circumference when a large load is input, and the durability of the main rubber elastic body 16 is improved.

Since the hollow portion 24 extends in the axial direction with a substantially constant inner diameter, concentration of strain on the inner surface 26 of the hollow portion 24 is less likely to occur when the main rubber elastic body 16 is elastically deformed.

FIG. 4 shows an engine mount 50 for an automobile as a second embodiment of a tubular vibration damping device constructed according to the present invention. The engine mount 50 has a structure in which an inner shaft member 52 and an outer cylindrical member 14 are connected by a main rubber elastic body 16 . In the following description, members and parts that are substantially the same as those of the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted.

The inner shaft member 52 has a plate-like portion 18 and a shaft body 54 extending downward from the inner peripheral end portion of the plate-like portion 18 . The shaft body 54 has a small-diameter cylindrical shape extending linearly in the vertical direction. A flange-like portion 56 protruding to the outer periphery is provided on the upper end portion of the shaft body 54 over the entire circumference, so that the fixing strength between the shaft body 54 and the plate-like portion 18 is ensured.

A deformation control member 58 is attached to the shaft body 54 of the inner shaft member 52 . The deformation control member 58 is a separate member from the inner shaft member 52 . The deformation control member 58 has an annular shape and is externally fitted and fixed to the shaft body 54 . The outer peripheral surface of the deformation control member 58 is defined as a deformation control surface 34 having an overlap region 60 and a release region 62 .

The overlapping region 60 is a cylindrical surface extending along the inner surface 26 of the hollow portion 24 of the main rubber elastic body 16 . The overlapping region 60 is provided in the vertical middle portion of the deformation control member 58 .

The release area 62 has a tapered surface whose diameter gradually decreases downward. The release area 62 of this embodiment is a curved surface that protrudes toward the outer periphery. Whereas in the first embodiment the overlap region 36 and the release region 38 had a stepped shape, in this embodiment the overlap region 60 and the release region 62 are provided in a continuous shape rather than stepped. ing. The release region 62 gradually separates from the inner surface 26 of the hollow portion 24 of the main rubber elastic body 16 toward the inner circumference as it goes downward from the overlapping region 60 .

The deformation control member 58 is fitted to the outer peripheral surface of the shaft body 54 that constitutes the inner shaft member 52 and is fixed to the shaft body 54 . A contact portion 64 protruding upward is provided at the inner peripheral end portion of the deformation control member 58, and the contact portion 64 is overlapped with the flange-shaped portion 56 of the shaft body 54 from below in a contact state. As a result, the deformation control member 58 is positioned vertically with respect to the shaft body 54 .

As shown in FIG. 5, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including not only the plate-like portion 18 of the inner shaft member 52 and the outer cylindrical member 14, but also the shaft main body 54 of the inner shaft member 52. ing. The plate-like portion 18 and the shaft main body 54 are fixed to each other by means such as welding in advance, for example, before vulcanization molding of the main rubber elastic body 16 .

A separate deformation control member 58 is attached to the shaft main body 54 of the inner shaft member 52 vulcanized and bonded to the main rubber elastic body 16 . The deformation control member 58 is inserted into the hollow portion 24 of the main rubber elastic body 16 from the opening 28 on the lower side, and as shown in FIG. be done. The overlapping region 60 of the deformation control member 58 attached to the shaft body 54 has a cylindrical shape along the inner surface 26 of the hollow portion 24 and overlaps the inner surface 26 of the hollow portion 24 in a contact state. The release region 62 of the deformation control member 58 is positioned inner than the inner surface 26 of the hollow portion 24 , and a gap is provided between the release region 62 and the inner surface 26 of the hollow portion 24 .

In the engine mount 50 of this embodiment, the deformation control surface 34 is configured by a separate member that is externally fitted and fixed to the inner shaft member 52 . Therefore, for example, by fitting and fixing the deformation control member 58 having the deformation control surface 34 to the shaft main body 54 of the inner shaft member 52 vulcanized and bonded when the main rubber elastic body 16 is molded, retrofitting is possible. can be set in

In the engine mount 50, when a vertical compressive load acts on the main rubber elastic body 16, as shown in FIG. ) abut not only the overlap region 60 of the deformation control member 58 but also the release region 62 . As a result, as in the first embodiment, the strain of the main rubber elastic body 16 is dispersed, thereby improving the durability of the main rubber elastic body 16 .

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the specific descriptions. For example, the deformation control surface need not have the same cross-sectional shape over the entire circumference, and the shape may change in the circumferential direction. The deformation control surface is not necessarily formed continuously over the entire circumference, and may be partially provided in the circumferential direction, or may be provided in plurality in the circumferential direction.

A specific shape of the deformation control surface is not particularly limited as long as the overlapping area and the release area are provided. For example, the release area may have a multi-stage structure with different projecting heights. According to this, since the contact area of the main rubber elastic body with the deformation control surface changes in multiple stages according to the amount of deformation of the main rubber elastic body, the strain distribution of the main rubber elastic body is more effective. can be intentionally planned.

When the engine mount 10 is attached to the vehicle, the shared support load of the power unit is input to the main rubber elastic body 16 , so that the inner surface 26 of the main rubber elastic body 16 is at least part of the release area 38 of the inner shaft member 12 . You may make it contact|abut. In short, the contact area of the main rubber elastic body 16 with the deformation control surface 34 is expanded from the overlap area 36 toward the release area 38 by further inputting a load such as vibration while the main rubber elastic body 16 is mounted on the vehicle. Alternatively, the overlap region 36 may spread toward the release region 38 by inputting the shared support load of the power unit when the vehicle is mounted. The contact area of the main rubber elastic body 16 with the deformation control surface 34 is widened by the input of the shared support load of the power unit, making it easier to adjust the ratio between the axial spring constant and the axial spring constant. That is, the ratio of the spring constant in the direction perpendicular to the axis to the spring constant in the axial direction can be adjusted to a large extent, and the degree of freedom in tuning the spring constant can be increased.

In addition, the deformation control surface on the inner shaft member side is provided with a maximum protrusion in the overlap region, and the portion extending from the maximum protrusion to the release region should not have an inclination in the direction in which the protrusion height increases. , preferably extend in the axial direction with faces having the same protrusion height or faces with smaller protrusion heights. Furthermore, in the portion extending from the maximum projection to the release area, it is preferable that the inclination angle in the axial direction changes gradually or stepwise, and at the change points of the inclination angle, the tangent line is smooth so that it is common. It is desirable to be connected and change.

The inner surface of the hollow portion of the main rubber elastic body that contacts the deformation control surface on the inner shaft member side also has an inner diameter that increases from the bottom side (the plate-like portion side of the inner shaft member) toward the opening side (the side opposite to the plate-like portion). It is desirable to extend axially with the same inner diameter or faces of increasing inner diameter so as not to reduce the dimensions. The bottom surface of such a cavity may also take into consideration the taper of the mold during molding. Incidentally, in the embodiment shown in FIGS. 2 and 5, the inner surface 26 of the hollow portion 24 of the main rubber elastic body 16 extends slightly over substantially the entire length in the axial direction below the bite-off portion of the rubber at the upper end. It has a tapered inner peripheral surface that expands downward at a constant inclination angle.

Due to the relative combination of the deformation control surface on the inner shaft member side and the inner surface of the hollow portion of the main rubber elastic body, at least in the release region, the distance between the surfaces facing each other in the direction perpendicular to the axis increases from the bottom side of the hollow portion. It is desirable to set the distance between the opposing surfaces to be the same or to increase the distance between the opposing surfaces so as not to narrow toward the opening side. Of course, the deformation control surface on the inner shaft member side and the inner surface of the hollow portion of the main rubber elastic body have different rates of change in the inclination angle in the axial direction, so that the contact area becomes non-linear when a load is input. , thereby allowing a non-linear rise in the spring characteristic to be set.

In addition, the inner surface 26 of the hollow portion 24 of the main rubber elastic body 16 in the above-described embodiment is not folded back toward the opening side, particularly at the bottom portion side. Even if there is no contact, localized stress and strain concentrations are avoided compared to conventionally constructed hollow holes. Note that the deformation control surface 34 on the inner shaft member 12 side and the inner surface 26 of the hollow portion 24 of the main rubber elastic body 16 are at least the deformation control surfaces when they are mounted on the vehicle and a supporting load such as a power unit is applied. It is desirable that the inner surface 26 of the hollow portion 24 of the main rubber elastic body 16 is in contact with the inner surface 26 of the main rubber elastic body 16 at, for example, the maximum outer diameter portion of the overlapping region 36 of 34 . However, in the above-described embodiment, between the axially facing surfaces of the large-diameter portion 32 and the plate-like portion 18, between the axially facing surfaces of the deformation control member 58 and the flange-like portion 56, and the like, the stress generated when the load is input. Since the main rubber elastic body 16 is not required to be filled, it may be a hollow space or the like.

In the above-described embodiment, the outer tubular member 14 is provided with the expanded portion 22 that curves upward in the axial direction, and the flange-shaped portion is provided at the upper end portion in the axial direction of the outer tubular member 14 . On the other hand, the axially lower portion is formed with a cylindrical portion 21 extending in the axial direction with a substantially constant diameter, and the lower end opening is provided with an inner flange portion 23 that can be used for reinforcement or as a stopper. was The deformation control surface 34 as a whole is provided at a position axially above the small-diameter cylindrical portion 21 provided in the axially lower portion of the outer cylindrical member 14 . and the outer tubular member 14 are arranged to secure a rubber volume. 3 and 6, the axis-perpendicular stopper projection 46 is positioned so as to face the small-diameter tubular portion 21 of the outer tubular member 14 in the axis-perpendicular direction. It is set to improve the stopper function.

When the deformation control member 58 constituting the deformation control surface 34 is a separate member from the shaft body 20, the shaft body 20 and the deformation control member 58 are combined with each other to form the main rubber elastic body 16. It may be set in a mold and vulcanized and bonded to the main rubber elastic body 16 . In short, when the separate deformation control member 58 is adopted, the deformation control member 58 is limited to being attached to the shaft body 20 after vulcanization molding of the main rubber elastic body 16 as in the second embodiment. not.

The tubular vibration isolator is not necessarily limited to a rotationally symmetrical shape, and may have, for example, an elliptical shape when viewed in the axial direction.

10,50 Engine mount (cylindrical anti-vibration device)
12, 52 Inner shaft member 14 Outer cylindrical member 16 Main rubber elastic body 18 Plate-shaped portions 20, 54 Shaft main body 21 Cylindrical portion 22 Expanded portion 23 Inner flange-shaped portion 24 Cavity 26 Inner surface 28 Opening 30 Upper portion 31 Periphery Surface 32 Large diameter portion 34 Deformation control surfaces 36, 60 Overlapping areas 38, 62 Release area 40 First tapered surface 42 Cylindrical surface 44 Second tapered surface 46 Stopper protrusion 56 Flange-shaped portion 58 Deformation control member 64 Contact Department

Claims (8)

A cylindrical vibration damping device in which an inner shaft member having a plate-shaped portion at one end in the axial direction and an outer cylindrical member having a widened portion at one end in the axial direction are connected by a main rubber elastic body,
The main rubber elastic body is provided with a hollow portion that opens to the other axial end face and extends axially toward the plate-like portion on the outer peripheral surface of the inner shaft member,
The inner shaft member is provided with a deformation control surface protruding on the outer peripheral surface, and
The deformation control surface is provided with an overlap region that extends along the inner surface of the cavity and a release region that gradually separates from the inner surface of the cavity from the overlap region toward the opening side of the cavity. ,
A cylindrical vibration damping device, wherein a contact area of the main rubber elastic body against the deformation control surface widens from the overlap area toward the release area as the input load increases. 2. A cylindrical vibration isolator according to claim 1, wherein said deformation control surface is a curved surface in which a plurality of steps with stepped protrusion heights are connected smoothly in the axial direction. 3. A cylindrical vibration isolator according to claim 1, wherein said deformation control surface is formed by a large diameter portion integrally formed with said inner shaft member. The cylindrical vibration isolator according to any one of claims 1 to 3, wherein the deformation control surface is configured by a separate member that is externally fitted and fixed to the inner shaft member. The cylindrical vibration isolator according to any one of claims 1 to 4, wherein a stopper protrusion protruding from the inner shaft member into the cavity is provided at an intermediate portion in the depth direction of the cavity. 6. The tubular protector according to any one of claims 1 to 5, wherein the outer peripheral surface of the main rubber elastic body located on the outer peripheral side of the overlap region is a free surface that is not fixed to the outer tubular member. vibration device. 7. The method according to any one of claims 1 to 6, wherein the deformation control surface is continuous over the entire circumference, and the overlapping region of the deformation control surface extends along the inner surface of the cavity over the entire circumference. A cylindrical vibration isolator as described. The cylindrical vibration isolator according to any one of claims 1 to 7, wherein the cavity extends axially with a substantially constant inner diameter.

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