JP2009222094A - Dynamic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dynamic damper for effectively damping the vibration of a vibrating body by giving good vibration to a damper mass in an intended vibration damping direction, while avoiding possible influences on damper property due to an atmospheric temperature and preventing the fall-off of the damper mass even when a rubber elastic body is broken. <P>SOLUTION: The dynamic damper 10 comprises a metal plate spring 36 provided in the direction of joining the damper mass 22 to a mounting bracket 20 so that its plate surface is directed in the vertical direction of the main vibration of an exhaust pipe 12, and fixed at its ends to the damper mass 22 and the mounting bracket 20. The rubber elastic body 24 is vulcanized and molded integrally with the damper mass 22 and the mounting bracket 20 into the condition of covering the metal plate spring 36 to form a composite spring which elastically supports the damper mass 22 with the rubber elastic body 24 and the metal plate spring 36 arranged in parallel between the damper mass 22 and the mounting bracket 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dynamic damper that is attached to a vibrating body in a state where a damper mass as a mass body is elastically supported by a rubber elastic body, and that controls the vibrating body by a dynamic vibration absorbing action.

  A dynamic damper in which a damper mass as a mass body is elastically supported by a rubber elastic body absorbs an excitation force applied to the vibration body from the outside by the vibration of the damper mass, and functions to suppress the vibration body. By matching the natural frequency of the sub-vibration system made of rubber elastic body with the vibration frequency of vibration, that is, the natural frequency of the vibration body (main vibration system), the vibration energy from the outside is dynamically absorbed by the vibration of the damper mass. However, the vibrating body is brought close to static, and has been conventionally used by being attached to various places where the vibration of the vehicle is large.

Here, the natural frequency of the dynamic damper is expressed by the following equation (1) where M is the mass of the damper mass and k ₁ is the spring constant of the rubber elastic body (in equation 1, f ₀ is the natural frequency).

The natural frequency f ₀ of the dynamic damper fit to the natural frequency of the vibrator, the resonance point of the vibrator by excluding from the scope of the conventional speed of the vehicle, it is possible to suppress the vibration of the vibrating body.

By the way, in a dynamic damper using a rubber elastic body as a spring in the sub-vibration system, there is a problem that the spring constant of the rubber elastic body is easily influenced by the ambient temperature, and the spring constant changes due to temperature change.
If the spring constant of the rubber elastic body changes, the natural frequency of the dynamic damper changes and the resonance of the vibration body cannot be suppressed sufficiently effectively.

For example, in a vehicle, an exhaust system member including an exhaust pipe and a muffler may vibrate greatly in the vertical direction due to resonance at a specific low frequency (for example, around 20 Hz) as the vehicle travels.
Therefore, conventionally, a dynamic damper is attached to such an exhaust system member, and the vibration is suppressed by the dynamic vibration absorbing action of the dynamic damper.

However, the ambient temperature around the exhaust system member is low at the start (particularly in winter), and the ambient temperature gradually increases as the vehicle travels. Along with this, the rubber elastic body, which was initially hard, gradually becomes softer as the ambient temperature rises due to running of the vehicle, and accordingly, the spring constant of the rubber elastic body changes from large to small.
As a result, the natural frequency (resonance frequency) of the dynamic damper also changes, making it difficult to sufficiently suppress the resonance of the vibrating body.

The exhaust system member is also supported in an anti-vibration state in a suspended state by an elastic support member called a muffler hanger. In this state, the exhaust system member is not only in the vertical direction but also in the front-rear direction and other directions as the vehicle travels. Also produces vibration.
Along with this, the damper mass of the dynamic damper attached to the exhaust system member also vibrates in various directions. That is, the damper mass causes a complicated vibration motion accompanied with the vibration in the main vibration direction of the exhaust system member.

However, when the damper mass causes such complicated and irregular vibration (motion), it becomes difficult to vibrate the damper mass at a target frequency in the original target direction, for example, in the vertical direction. It becomes difficult to sufficiently suppress the vibration suppression location (location with large vibration) in the target direction.
Such a problem is also disclosed in, for example, Patent Document 1 below.

  As the dynamic damper for the exhaust system member, as shown in FIG. 5 (A), a mounting member 200 and a damper mass 202 simply connected by a rubber elastic body 204 is used. If the rubber elastic body 204 breaks due to an incorrect input or an unexpected external input, the damper mass 202 may fall off.

  In this case, as shown in (b), the extension parts 206 and 208 are provided in the mounting bracket 200 and the damper mass 202, and the shaft body 210 is inserted into the insertion holes 212 of the extension parts 206 and 208. Therefore, it is conceivable to prevent the damper mass 202 from falling off (fail safe).

  However, if this is done, the required cost for the dynamic damper will increase, and the dynamic damper will become larger, resulting in the problem of requiring a large space for mounting.

  Although the above description has focused on the dynamic damper used for the exhaust system member, such a problem may also occur in common with the dynamic damper used in addition to the vibrating body other than the exhaust system member.

As a prior art related to the present invention, Patent Document 2 discloses a dynamic damper used by being attached to a vehicle rearview mirror.
Patent Document 3 below discloses a dynamic damper that is attached to a vibration body of an automobile and suppresses the vibration.
However, those disclosed in Patent Documents 2 and 3 do not have the subject of the present invention, and the configuration thereof is also different from the present invention.

Japanese Patent Laid-Open No. 7-4466 JP 2007-198477 A JP 2003-28234 A

  In the background of the above circumstances, the present invention can effectively vibrate the vibrator by effectively vibrating the damper mass in the damping direction intended for the damper mass, and the damper characteristics are hardly affected by the ambient temperature. The object of the present invention is to provide a dynamic damper that is small, inexpensive, and does not require a wide mounting space, which can prevent the damper mass from dropping even if the rubber elastic body breaks.

  Thus, according to the first aspect of the present invention, the damper mass as the mass body, the mounting bracket attached to the vibrating body, and the damper mass and the mounting bracket are elastically connected in a direction intersecting the main vibration direction of the vibrating body. A rubber elastic body that elastically supports the damper mass, and the vibration mass is controlled by vibrating the damper mass with shearing elastic deformation in the vibration direction of the rubber elastic body by an excitation force applied to the vibration body. In the dynamic damper to be vibrated, a metal plate spring is provided in a direction connecting the damper mass and the mounting bracket, and a plate surface is directed in a main vibration direction of the vibrating body, and one end of the metal plate spring is provided on the damper mass. The other end is fixed to the mounting bracket, and the rubber elastic body is integrally vulcanized and molded into the damper mass and the mounting bracket so as to cover the metal leaf spring, and is parallel between the damper mass and the mounting bracket. Arrangement Characterized in that said Aru in the rubber elastic body and the metal plate spring constituting the composite spring for elastically supporting the damper mass.

  According to a second aspect of the present invention, the damper mass is of a cantilever support type in which the damper mass is elastically supported in a cantilever state by the rubber elastic body and the metal leaf spring only on one side in the intersecting direction.

Effects and effects of the invention

As described above, in the dynamic damper in which the damper mass and the mounting bracket are elastically connected by the rubber elastic body in the direction intersecting the main vibration direction of the vibrating body, the metal plate spring is connected in the direction connecting the damper mass and the mounting bracket. In addition, the rubber plate is provided so that its plate surface faces the main vibration direction of the vibrating body, each end of the metal leaf spring is fixed to the damper mass and the mounting bracket, and the metal leaf spring is covered from the outside. The body is integrally vulcanized with a damper mass and a mounting bracket, and a rubber elastic body and a metal leaf spring arranged in parallel between the damper mass and the mounting bracket constitute a composite spring in the dynamic damper.
In the present invention, the spring constant of the composite spring composed of the rubber elastic body and the metal leaf spring is set in accordance with the resonance frequency in the main vibration direction of the vibrating body.

In the dynamic damper of the present invention, since the spring in the dynamic damper is a composite spring of a rubber elastic body and a metal plate spring, the spring in the dynamic damper is not easily affected by heat such as ambient temperature. The change of the spring constant due to the temperature change can be suppressed.
Thereby, the change of the resonance frequency of the dynamic damper due to the temperature change can be suppressed, and the vibrating body can be satisfactorily controlled by the dynamic damper.

In the present invention, since the plate spring is provided so that its plate surface faces the main vibration direction of the vibrating body, the damper mass can be selectively vibrated only in the main vibration direction of the vibrating body.
Usually, the vibrating body does not vibrate only in a certain direction, but vibrates in various directions.

Along with this, an excitation force is applied to the damper mass in various directions.
At this time, if the spring in the dynamic damper is composed of only a rubber elastic body, the damper mass also vibrates in various directions together with the vibrating body, and as a result, the damper mass vibrates irregularly with various vibration components.

  Then, it is difficult to vibrate the damper mass in the main vibration direction of the vibrating body at the target vibration frequency, and as a result, it becomes difficult to sufficiently absorb the vibration in the main vibration direction of the vibrating body with the dynamic damper. That is, it becomes difficult to fully exhibit the original performance as a dynamic damper.

  However, according to the present invention, the vibration direction of the damper mass is limited by the metal leaf spring, that is, the exciting force in various directions applied to the damper mass is excluded by the metal leaf spring, and the metal leaf spring is most easily bent, that is, easily deformed elastically. Since the damper mass vibrates only in the main vibration direction of the vibrating body, the dynamic damper of the present invention can be vibrated only in the main vibration direction of the vibrating body intended for the damper mass, and the vibrating body can be satisfactorily operated in the main vibration direction. Vibration can be suppressed.

  In the present invention, the direction of vibration of the damper mass can be easily and freely adjusted by changing the arrangement direction of the leaf springs, leaving the damper mass, the rubber elastic body, and the mounting bracket as they are. In addition, the spring constant of the composite spring in the dynamic damper is adjusted by changing the material, thickness, and other conditions of the metal leaf spring, which makes it possible to easily adjust the natural frequency of the damper mass to an appropriate frequency. .

  For example, when a dynamic damper is used for damping an automobile exhaust system member, if the main vibration direction changes due to changes in the vehicle type or the resonance frequency in the main vibration direction changes, the orientation of the leaf springs And it becomes possible to cope easily by appropriately tuning the spring constant.

  Alternatively, if the exhaust system member is resonating at different resonance frequencies in the normal speed range both in the vertical direction and in the front-rear direction, the same two different in the direction of the plate surface and the spring constant of the metal plate spring By using the dynamic damper for vibration suppression in the vertical direction and vibration suppression in the front-rear direction, it becomes possible to suppress both the main vibration in the vertical direction and the main vibration in the front-rear direction of the exhaust system member.

  In the present invention, each end is fixed to the damper mass and the mounting bracket so that the metal leaf spring connects the damper mass and the mounting bracket. Therefore, the rubber elastic body is broken by an excessive input or an unexpected input. Even if it happens, it is possible to prevent the damper mass from falling off and to realize fail-safe.

  In the present invention, since the metal plate spring is provided in a state of being covered with a rubber elastic body, the dynamic damper can be configured with the same size and shape as the dynamic damper without the metal plate spring. It can be configured in a small size, and the space for mounting the dynamic damper can be prevented from expanding by providing a metal leaf spring.

  In the present invention, the dynamic damper is of a cantilever support type in which the damper mass is elastically supported in a cantilever state by a rubber elastic body and a metal leaf spring only on one side in the direction intersecting with the main vibration direction of the vibration body. (Claim 2).

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, reference numeral 10 denotes a dynamic damper according to this embodiment, which is used here for damping an exhaust system member including the exhaust pipe 12.
As illustrated, the dynamic damper 10 is attached to the exhaust pipe 12 so as to be suspended from the exhaust pipe 12.
In FIG. 2, reference numeral 14 denotes a metal bracket for attaching the dynamic damper 10 to the exhaust pipe 12, a fixing portion 16 extending in an arc shape along the exhaust pipe 12, and a hanging portion depending from the right end of the fixing portion 16 in the figure. 18, and is fixed to the outer surface of the exhaust pipe 12 by welding at the fixing portion 16.

  The dynamic damper 10 includes a plate-shaped mounting member 20 and a mass body that is disposed apart from the mounting member 20 in the left-right direction, in this case, the left-right direction perpendicular to the vertical direction that is the main vibration direction of the exhaust pipe 12. And a rubber elastic body 24 that elastically connects the damper mass 22 and the mounting bracket 20 in the left-right direction and elastically supports the damper mass 22 in the vertical direction that is the main vibration direction of the exhaust pipe 12. is doing.

Here, the rubber elastic body 24 is integrally vulcanized with respect to the damper mass 22 and the mounting bracket 20. At the time of the vulcanization molding, the left end and the right end in the figure are vulcanized and bonded to the damper mass 22 and the mounting bracket 20.
Here, the damper mass 22 has a rectangular cross-sectional shape, and a side surface has a circular shape.
Similarly, the rubber elastic body 24 also has a rectangular cross-sectional shape, and a transverse cross-sectional shape in a direction perpendicular to this has a circular shape.

The damper mass 22 is elastically supported in a cantilevered state by a rubber elastic body 24 only on one side on the right side in the figure in the left-right direction perpendicular to the up-down direction, which is the main vibration direction of the exhaust pipe 12.
That is, the dynamic damper 10 of this embodiment is of the cantilever type, and the damper mass 22 is accompanied by shear elastic deformation in the vertical direction of the rubber elastic body 24 which is the main vibration direction of the exhaust pipe 12, and the main vibration direction of the exhaust pipe 12. It vibrates in the vertical direction.
At this time, the damper mass 22 swings in the vertical direction in the figure, thereby performing a dynamic vibration absorbing action and suppressing the vibration of the exhaust pipe 12.

The mounting bracket 20 has an upwardly extending portion 26, and a cylindrical portion 28 is provided there.
Then, the fastening bolt 32 is inserted into the insertion hole 30 of the cylindrical portion 28 and the insertion hole 30 of the bracket 14 from the left side in the drawing, and the nut 34 is screwed into the male screw portion protruding from the hanging portion 18 and tightened. A mounting bracket 20 is attached to the exhaust pipe 12 via the bracket 14 in a suspended state. That is, the dynamic damper 10 is attached to the lower side of the exhaust pipe 12 in a suspended state.

Reference numeral 36 denotes a metal leaf spring embedded in the rubber elastic body 24, which is oriented in the direction connecting the damper mass 22 and the mounting bracket 20 (the left-right direction in the figure).
The metal leaf spring 36 has bent portions 38 and 40 bent at right angles to the left end portion and the right end portion in the figure, and the bent portions 38 and 40 are in contact with the damper mass 22 and the mounting bracket 20. The bent portions 38 and 40 are fixed to the damper mass 22 and the mounting bracket 20 by welding, respectively.
In other words, in this embodiment, the mounting metal member 20 and the damper mass 22 are connected by the rubber elastic body 24, and the metal plate spring 36 connects the mounting metal member 20 and the damper mass 22 together.

As shown in FIGS. 2A and 3, the metal plate spring 36 is provided with its plate surface directed in the vertical direction.
In this embodiment, the rubber elastic body 24 and the metal plate spring 36 arranged in parallel between the damper mass 22 and the mounting bracket 20 constitute a composite spring that elastically supports the damper mass 22 in the vertical direction.

The spring constant K of the composite spring is expressed as k ₁ + k ₂ where the spring constant of the metal plate spring 36 in the vertical direction is k ₂ . Therefore, the natural frequency in the vertical direction of the dynamic damper 10 is expressed by the following equation (2).

In this embodiment, the spring constant K = k ₁ + k ₂ of the composite spring is tuned so that the natural frequency f ₀ matches the natural frequency (resonance frequency) of the exhaust pipe 12, specifically the vertical direction of the exhaust system member. The Rukoto.

  Various metal materials can be used for the metal leaf spring 36, and in particular, JIS G 4802 (cold rolled steel strip for spring) can be suitably used. In addition, JIS G 4313 (stainless steel strip for spring) and other materials can be used.

In this embodiment, the metal plate spring 36 is provided with its plate surface facing the vertical direction, which is the main vibration direction of the exhaust pipe 12, so that the damper mass 22 is selectively vibrated in the vertical direction, and the other directions. Vibration is restricted.
That is, even when vibrations are applied in various directions from the outside, vibrations in directions other than the vertical direction are eliminated, and only the vibrations in the vertical direction are extracted and the damper mass 22 is selectively vibrated only in the vertical direction. .

In the dynamic damper 10 of the present embodiment as described above, since the spring in the dynamic damper 10 is a composite spring of the rubber elastic body 24 and the metal plate spring 36, the spring constant in the dynamic damper 10 is as follows. It is difficult to be affected by heat such as ambient temperature, and the change in spring constant due to temperature change can be suppressed.
Thereby, the change of the resonance frequency of the dynamic damper 10 due to the temperature change can be suppressed, and the exhaust system member can be satisfactorily controlled by the dynamic damper 10.

Further, in the present embodiment, the metal plate spring 36 is provided with its plate surface facing the vertical direction, which is the main vibration direction of the exhaust pipe 12, so that the damper mass 22 is selectively only in the main vibration direction of the exhaust system member. It can be vibrated.
Thereby, the exhaust system member can be satisfactorily suppressed in the main vibration direction.

  In the present embodiment, the metal leaf spring 36 is fixed to the damper mass 22 and the mounting bracket 20 at the bent portions 38 and 40 so as to connect the damper mass 22 and the mounting bracket 20. Even if the rubber elastic body 24 breaks due to the input, it is possible to prevent the damper mass 22 from falling off and to realize fail-safe.

  In addition, in this embodiment, since the metal plate spring 36 is provided in a state of being covered with the rubber elastic body 24, the dynamic damper 10 has the same dimensions as the dynamic damper 10 that does not include the metal plate spring 36. The dynamic damper 10 can be configured in a small size, and the space for mounting the dynamic damper 10 can be prevented from being enlarged by providing the metal plate spring 36.

  In the present embodiment, the direction of the vibration of the damper mass 22 can be easily and freely adjusted by changing the arrangement direction of the metal plate spring 36 while leaving the damper mass 22, the rubber elastic body 24, and the mounting bracket 20 as they are. be able to. Further, by changing the material, thickness and other conditions of the metal leaf spring 36, the spring constant of the composite spring in the dynamic dampers 10 and 42 is adjusted, so that the natural frequency of the damper mass 22 can be easily adjusted to an appropriate frequency. Has adjustable characteristics.

  For example, when the main vibration direction of the exhaust system member changes due to the change of the vehicle type or the resonance frequency in the main vibration direction changes, the direction of the arrangement of the metal plate spring 36 and its spring constant are appropriately tuned. It is possible to easily cope with this.

  Alternatively, when the exhaust system member is resonating at different resonance frequencies in the normal speed range both in the vertical direction and in the front-rear direction, the same two different in the direction of the plate surface and the spring constant of the metal plate spring 36 are different. By using the dynamic damper for vibration suppression in the vertical direction and vibration suppression in the front-rear direction, it becomes possible to suppress both the main vibration in the vertical direction and the main vibration in the front-rear direction of the exhaust system member.

FIG. 4 shows a specific example thereof.
In this example, a pair of dynamic dampers 10 and 42 are attached to the exhaust system member, specifically, the exhaust pipe 12 to constitute a vibration isolator for damping the exhaust pipe 12.
Here, the dynamic damper 42 is structurally different from the dynamic damper 10 only in the direction of the metal leaf spring 36, and is the same as the dynamic damper 10 in other points.

Specifically, in the dynamic damper 10, the metal plate spring 36 is provided with the plate surface facing in the vertical direction, but in the dynamic damper 42, the metal plate spring 36 is provided with the plate surface in the longitudinal direction of the vehicle.
Here, the dynamic damper 42 excludes the resonance in the front-rear direction in the normal speed range of the exhaust system member, and the spring constant in the front-rear direction of the metal leaf spring 36 is set in accordance with the resonance frequency in the front-rear direction of the exhaust system member. ing. That is, the composite spring constant in the front-rear direction of the metal plate spring 36 and the rubber elastic body 24 is tuned with respect to the resonance frequency in the front-rear direction of the exhaust system member (in this case, the main vibration direction of the exhaust system member is the vertical direction). Two directions, the front-rear direction).

  Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be configured in various forms without departing from the spirit of the present invention.

It is a perspective view which shows the dynamic damper which is one Embodiment of this invention in the attachment state to an exhaust pipe. It is the partially notched front view and side sectional drawing of the dynamic damper of the embodiment. It is a disassembled perspective view which shows the dynamic damper of the embodiment except a rubber elastic body. It is a figure of other embodiment of this invention. It is a figure which shows an example of the conventional dynamic damper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,42 Dynamic damper 12 Exhaust pipe 20 Mounting bracket 22 Damper mass 24 Rubber elastic body 36 Metal leaf spring

Claims (2)

A damper mass as a mass body, a mounting bracket attached to and fixed to the vibrating body, and a rubber elastic body that elastically supports the damper mass by elastically connecting the damper mass and the mounting bracket in a direction crossing the main vibration direction of the vibrating body. The damper plate is vibrated with shearing elastic deformation in the vibration direction of the rubber elastic body by the vibration force applied to the vibration body, and the metal plate spring is disposed in the dynamic damper that dampens the vibration body. Provided in a direction connecting the damper mass and the mounting bracket and with the plate surface facing the main vibration direction of the vibrating body, and fixing one end of the metal plate spring to the damper mass and the other end to the mounting bracket The rubber elastic body and the metal plate are formed by integrally vulcanizing and molding the rubber elastic body on the damper mass and the mounting bracket so as to cover the metal plate spring, and arranged in parallel between the damper mass and the mounting bracket. A dynamic damper comprising a composite spring that elastically supports the damper mass with a spring.   The dynamic damper according to claim 1, wherein the damper mass is of a cantilever support type that is elastically supported in a cantilever state by the rubber elastic body and the metal leaf spring only on one side in the intersecting direction.

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