JP7457635B2 - Vibration isolator - Google Patents

Description

The present disclosure relates to a vibration isolating device that is used as a mount for a frame or member of an automobile, and absorbs and damps vibrations transmitted to a vehicle body.

Conventionally, in vibration isolation devices using solid rubber as subframe mounts in automobiles, small vibrations can occur due to the weight of the subframe and resonance caused by the spring characteristics of the subframe mount. To suppress such vibrations, it is common to use rubber members with damping properties.

In addition, in such vibration isolation devices, a structure is also known in which a stopper is provided to limit the amount of movement of the inner tube surrounded by rubber (Patent Document 1).

Japanese Patent Application Publication No. 2014-224557

In the vibration isolating device as described above, the damping is uniform within the rubber member, and therefore is approximately constant regardless of the direction of displacement of the rubber member.

Since the damping of the rubber member has amplitude dependence, the rubber member has high rigidity especially in the region of small amplitude. Therefore, the rigidity is high even in directions that do not require damping, which may cause noise such as road noise.

Furthermore, when using a highly attenuated member, there is also the problem that it may deteriorate prematurely if it is continued to be used with a load applied to it.

Note that with the structure provided with the stopper as described above, it is difficult to set the required rigidity and damping characteristics.

Therefore, the following disclosure has been made in view of this situation, and aims to provide a vibration isolating device that can flexibly set required rigidity and damping characteristics.

One aspect of the present disclosure includes an inner cylinder (inner cylinder 200) into which a shaft-shaped member is inserted, an outer cylinder (outer cylinder 300) provided on the radially outer side of the inner cylinder, and an inner cylinder and the outer cylinder. A main body rubber (main body rubber 250) provided between the inner cylinder and the outer cylinder, and a damping member (damping member 400) separate from the main body rubber, the damping member is provided between the inner cylinder and the outer cylinder. A damping section (damping section 430) that is provided between the cylinder and the main body rubber in the axial direction of the inner cylinder and that constitutes the damping member is made of a material with higher damping than the main body rubber. This is a vibration isolator (vibration isolator 100) formed by.

The above-mentioned vibration isolation device allows the required stiffness and damping characteristics to be flexibly set.

FIG. 1 is a perspective view of a vibration isolator 100. FIG. 2 is a cross-sectional view of the vibration isolator 100. FIG. 3 is a perspective view of the damping member 400 alone. FIG. 4 is an exploded perspective view of the damping member 400. FIG. 5 is an exploded plan view of the damping member 400. FIG. 6 is an explanatory diagram of a characteristic image when a low attenuation member and a high attenuation member are used together. FIG. 7 is a sectional view of a vibration isolator 100A according to a modified example.

The following describes the embodiments with reference to the drawings. Note that identical or similar symbols are used for identical functions and configurations, and descriptions thereof will be omitted as appropriate.

(1) Appearance of vibration isolator FIG. 1 is a perspective view of a vibration isolator 100 according to the present embodiment. As shown in FIG. 1, the vibration isolator 100 has a cylindrical shape and is used as a mount for a frame or member of an automobile, and absorbs and damps vibrations transmitted to the vehicle body.

In particular, the vibration isolator 100 can be suitably used as a subframe mount for an automobile. A subframe is a part that forms part of the frame (skeleton) of an automobile and is fastened to the vehicle body to support heavy objects such as a power train such as an engine, a suspension, and a steering gear box. Although the vibration isolator 100 is provided between the subframe and the vehicle body (frame body), it may also be used as a bushing for an automobile suspension, for example, in addition to such a subframe mount.

As shown in FIG. 1, the vibration isolator 100 has an outer cylinder 300, and a cavity 110 is formed along the axial direction of the vibration isolator 100, specifically, along the direction of the straight line L1. The cavity 110 is a space for inserting a shaft member such as a bolt that is fastened to the subframe.

(2) Structure of vibration isolator FIG. 2 is a sectional view of the vibration isolator 100. Specifically, FIG. 2 is a cross-sectional view of the vibration isolator 100 along the axial direction (line L1 direction, see FIG. 1).

As shown in FIG. 2, the vibration isolator 100 includes an inner cylinder 200, an outer cylinder 300, and a main body rubber 250. A shaft-shaped member such as a bolt (not shown) for fastening to the subframe is inserted into the inner cylinder 200. Specifically, the inner cylinder 200 has a cavity 110 formed therein.

The outer cylinder 300 is provided radially outside the inner cylinder 200. It is preferable that the radial size of the outer cylinder 300 is sufficiently larger than the radial size of the inner cylinder 200. The inner cylinder 200 and the outer cylinder 300 may be formed using a general metal material (or a resin material).

An extending portion 310 is formed at one end (lower end) of the outer cylinder 300 in the axial direction. Further, a flange portion 320 is formed at the other end (upper end) of the outer cylinder 300 in the axial direction.

The extending portion 310 extends radially inward from the inner surface of the outer cylinder 300. The extending portion 310 may be formed by bending the lower end of the outer cylinder 300, or may be formed separately from or integrally with the outer cylinder 300.

The flange portion 320 extends radially outward from the upper end of the outer cylinder 300. The flange portion 320 may also be formed by bending the upper end of the outer tube 300, or may be formed separately from or integrally with the outer tube 300. The flange portion 320 may also function to lock the rubber body 250 and position the rubber body 250 in the axial direction.

The main body rubber 250 is provided between the inner cylinder 200 and the outer cylinder 300 and holds the inner cylinder 200. The main body rubber 250 is not provided in all the space between the inner cylinder 200 and the outer cylinder 300, and a part of the space may be a void.

However, depending on the performance required of the vibration isolator 100, the material of the rubber body 250, etc., the rubber body 250 may be provided in the entire space. Furthermore, a member such as a sleeve may be interposed on the outer peripheral surface of the main rubber body 250, as shown in FIG.

For the main body rubber 250, a general rubber material used for this type of mount may be used. For example, EPDM (ethylene propylene rubber), CR (chloroprene rubber), NBR (acrylonitrile butadiene rubber), urethane rubber, or natural rubber (NR) may be used.

The vibration isolator 100 also includes a damping member 400 that is separate from the main body rubber. The damping member 400 is arranged between the inner cylinder 200 and the outer cylinder 300 in a region within the outer cylinder 300 where the main body rubber 250 is not present.

That is, the damping member 400 is provided between the inner cylinder 200 and the outer cylinder 300, and may be provided at a different position from the main rubber body 250 in the axial direction of the inner cylinder 200.

Specifically, the damping member 400 may be provided adjacent to the main rubber body 250 in the axial direction. The rubber body 250 and the damping member 400 may be in contact with each other as shown in FIG. 2, or may be separated from each other to some extent (especially the rubber body 250 and the damping portion 430, which will be described later).

Damping member 400 is formed of a material with higher damping than body rubber 250. That is, a portion of the damping member 400, including at least the portion that contacts the inner cylinder 200, may be formed of a material having a larger damping amount than the main rubber 250. The detailed structure of the damping member 400 will be described later.

The extending portion 310 of the outer cylinder 300 is formed at the axial end of the outer cylinder 300 on the side where the damping member 400 is provided. The extending portion 310 may also function to lock the damping member 400 and position the damping member 400 in the axial direction.

In this way, the bottom part of the outer cylinder 300 of the vibration isolator 100 has a cup structure, and after the damping member 400 (also called a high damping member) is lightly press-fitted, the main body rubber 250 (also called a low damping member) is attached. The structure is such that it is press-fitted and fixed.

(3) Structure of the damping member 400 FIG. 3 is a perspective view of the damping member 400. FIG. 4 is an exploded perspective view of the damping member 400. FIG. 5 is an exploded plan view of the damping member 400.

As shown in FIGS. 3 to 5, the damping member 400 includes a peripheral edge portion 410 along the inner circumferential surface of the outer tube 300. As shown in FIGS. Further, the damping member 400 includes an inner cylinder portion 420 and a damping portion 430. The peripheral portion 410 is composed of a circular arc portion 411 and a circular arc portion 412.

The peripheral portion 410 is circular along the inner circumferential surface of the outer cylinder 300, and can be divided into a plurality of arcuate portions 411 and a plurality of arcuate portions 412 in the circumferential direction.

The arc-shaped portion is provided with an engaging element for engaging with another adjacent arc-shaped portion. Specifically, arc-shaped portion 411 and arc-shaped portion 412 are engaged with each other by guide portion 413.

The guide portion 413 prevents the engagement position of the arcuate portion 411 and the arcuate portion 412 from shifting and prevents the arcuate portion 411 and the arcuate portion 412 from separating. In this embodiment, the guide portion 413 is configured by a plurality of convex portions and a plurality of concave portions into which the convex portions are press-fitted.

Note that the guide portion 413 may be constituted by a different engagement element such as a hook-shaped portion. Alternatively, instead of the guide portion 413, a structure that allows a narrowing so that the inner diameter of the peripheral portion 410 can be reduced may be adopted.

The inner cylinder portion 420 has a circular shape along the outer peripheral surface of the inner cylinder 200. The cavity 440 communicates with the cavity 110 (see FIG. 2, etc.), and a shaft-shaped member such as a bolt is inserted therethrough.

Note that the peripheral portion 410 and the inner cylinder portion 420 may be formed using a general metal material (or resin material).

On the other hand, the damping section 430 is a component of the damping member 400 and is formed of a material with higher damping than the main body rubber 250. Specifically, it is preferable that the loss tangent (tan δ) of the material forming the damping portion 430 is higher than the tan δ of the material forming the main body rubber 250. Although the numerical range of tan δ is not clearly limited, it is preferably about 0.6 to 0.7 for applications such as subframe mounts. Note that tan δ may be interpreted as the ratio (E''/E') between the storage elastic modulus E' and the loss elastic modulus E''.

As a material constituting the damping section 430, for example, urethane resin can be used. The damping portion 430 (urethane resin) is compressed by the peripheral portion 410. Specifically, by sandwiching the damping section 430, which is larger in size than the inner diameter of the peripheral edge section 410, between the circular arc portion 411 and the circular arc portion 412, initial compression (precompression) is applied to the damping section 430.

If a tensile load is applied to the vibration isolator 100 during use, its durability will deteriorate. Therefore, the damping member 400 (damping section 430) is assembled in a compressed state in consideration of durability so that it does not become tensile within the normal displacement range.

Specifically, the damping member 400 has a structure that assumes the initial shape when a load of 1W (1G) is applied, and the entire load at the time of 1W load is carried out using the main body rubber 250, which has high durability and resistance to fatigue. (low damping member).

The damping part 430 is not necessarily provided in all the space between the peripheral part 410 and the inner cylinder part 420, and a gap 450 may be formed. Note that the gap 450 may be formed near the guide section 413 in order to avoid interference between the guide section 413 and the damping section 430.

(4) Actions and Effects According to the embodiment described above, the following effects can be obtained. Specifically, the vibration isolator 100 includes a rubber body 250 and a damping member 400 that is separate. The damping member 400 is provided between the inner cylinder 200 and the outer cylinder, and is provided at a different position from the main rubber body 250 in the axial direction of the inner cylinder 200. Further, the damping section 430 constituting the damping member 400 is formed of a material with higher damping than the main body rubber 250.

By combining the main body rubber 250 (low damping member) and the damping member 400 (high damping member), the damping in any direction can be increased and the main body rubber 250 (such as conventional rubber material with strong repulsive force and low damping) can be used. ) by applying (receiving) a 1W (1G) load, damping members 400 with large sag (such as rubber or resin materials such as urethane, which have weak repulsive force and are particularly characterized by shock absorption) can also be applied. It becomes possible.

FIG. 6 is an explanatory diagram (Lissajous figure) of a characteristic image when a low attenuation member and a high attenuation member are used together. As shown in Fig. 6, when a low damping member and a high damping member are used together, a vibration isolator has a new characteristic that combines the characteristics of the low damping member and the high damping member in the load-displacement characteristics. 100 can be given.

In this manner, desired composite characteristics can be obtained relatively easily by adjusting the characteristics of the high damping member combined with the low damping member. Specifically, the stiffness and damping of the vibration isolator 100 can be arbitrarily set by combining the damping force ratio in each direction of the high damping member and the stiffness force ratio in each direction of the low damping member.

In the case of conventional subframe mounts, it is common to use a rubber member with a certain damping property to deal with small vibrations caused by the weight of the subframe and resonance due to the spring characteristics of the subframe mount. be.

However, since the damping is uniform within the rubber member, it is approximately constant regardless of the direction of displacement of the rubber member.

Since the damping of the rubber member has amplitude dependence, the rubber member has high rigidity especially in the region of small amplitude. Therefore, the rigidity is high even in directions that do not require damping, which may cause noise such as road noise. Furthermore, when using a high-damping member, there is also the problem that if the member is continued to be used under a load, it will deteriorate prematurely.

According to the vibration isolating device 100 described above, such problems can be solved and the required stiffness and damping characteristics can be flexibly set.

Specifically, since the main body rubber 250 bears the 1W (1G) load, it is possible to effectively suppress fatigue of the damping member 400 (damping section 430). Furthermore, by using a separate damping member 400, damping performance in any direction can be ensured.

In this embodiment, the damping section 430 is assembled with precompression applied by the peripheral portion 410, so that the durability of the damping section 430 can also be improved. Further, since the arcuate portion 411 and the arcuate portion 412 can be engaged with each other by the guide portion 413, precompression can be easily applied to the damping portion 430, and manufacturing is easy.

Furthermore, in the present embodiment, the axial end of the outer tube 300 on the side where the damping member 400 is provided is provided with an extending portion 310 that extends radially inward from the inner surface of the outer tube 300. Press-fitting and positioning of the body damping member 400 into the outer cylinder 300 becomes easy.

(5) Other Embodiments Although the embodiments have been described above, the present invention is not limited to the description of the embodiments, and it will be obvious to those skilled in the art that various modifications and improvements are possible.

For example, the vibration isolation device 100 described above may be modified as follows. Figure 7 is a cross-sectional view of a vibration isolation device 100A according to a modified example.

As shown in FIG. 7, the vibration isolation device 100A differs from the vibration isolation device 100 in that it further includes an interleaf 270.

The interleaf 270 is a plate (leaf)-shaped member that extends in the axial direction. Although the interleaf 270 is located between the inner cylinder 200 and the outer cylinder 300, it does not necessarily have to be provided over the entire circumference of the inner cylinder 200 (outer cylinder 300).

The interleaf 270 may function as a low damping member like the main rubber 250A. Alternatively, interleaf 270 may function as a high damping member.

When the spring characteristics of the low damping material increase, the contribution of the high damping material decreases, so tan δ decreases; conversely, when the spring characteristics decrease, tan δ increases.

In addition, in the embodiment described above, the damping member 400 was press-fitted into the outer cylinder 300, but the damping member 400 (high damping member) may be fixed (adhered) to a metal etc. as an outer part. It may also be integrally molded with a high hardness resin.

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended as an illustrative example and does not have any limiting meaning on the present disclosure.

100, 100A vibration isolator
110 Cavity
200 inner cylinder
250, 250A body rubber
270 Interleaf
300 outer cylinder
310 Extension part
320 Flange part
400 Damping member
410 Periphery
411, 412 Arc-shaped part
413 Guide section
420 Inner cylinder part
430 Attenuation section
440 Cavity
450 void

Claims (2)

an inner cylinder into which the shaft member is inserted;
an outer cylinder provided on the radially outer side of the inner cylinder;
a main body rubber provided between the inner cylinder and the outer cylinder and holding the inner cylinder;
comprising a damping member separate from the main body rubber,
The damping member is provided between the inner cylinder and the outer cylinder, and is provided at a different position from the main body rubber in the axial direction of the inner cylinder,
The damping portion constituting the damping member is formed of a material with higher damping than the main body rubber ,
Furthermore, the damping member includes a peripheral edge along the inner circumferential surface of the outer cylinder,
the damping portion is compressed by the peripheral edge portion;
The peripheral edge portion is divided into a plurality of arcuate portions in the circumferential direction,
A vibration isolator , wherein the arcuate portion is provided with an element for engagement with another adjacent arcuate portion . The vibration isolator according to claim 1 , wherein an axial end portion of the outer tube on the side where the damping member is provided extends radially inward from an inner surface of the outer tube .

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