JP2000337431A - Dynamic damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To soften the spring characteristics of a rubber elastic body in the axial direction of a dynamic damper and to suppress oscillation of a mass fitment. SOLUTION: This dynamic damper comprises an inner cylinder fitment 11; an outer cylinder fitment 12; and a rubber elastic body 13 disposed between the opposite surfaces of the inner and outer cylinder fitments and having a through-hole axially extending through a plurality of spots in a peripheral direction in a plurality of spots in a peripheral direction togetherwith a coupling part elastically intercoupling the two fitments at a central part in an axial direction. By pressing the outer cylinder fitment in the central hole of a mass fitment 20, the mass fitment is fixed in the concentric position on the outer peripheral side of the outer cylinder fitment. An annular seat metal member 25 having an outside diameter larger than the inside diameter of the outer cylinder fitment is supported in a cantilever state on the mounting member by fixing it to the mounting side of a vehicle on one end side of the inner cylinder fitment such that an axial direction is extended in a vertical direction and meanwhile, the seat metal member is locked on the other end side of the outer cylinder fitment by a bolt nut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper mounted on a member such as a vehicle, and more particularly to a dynamic damper suitable for attenuating vibration in a low frequency range.

[0002]

2. Description of the Related Art Conventionally, this kind of dynamic damper is
For example, as shown in FIG. 5, a flat mounting bracket 1, a cylindrical mass bracket 2 opposed to a plane thereof at a predetermined distance, and a substantially cylindrical shape connecting the mounting bracket 1 and the mass bracket 2. And a connecting portion 3 made of a rubber elastic body. The connecting portion 3 is attached to a vehicle body-side member supporting an automobile engine by fixing the mounting bracket 1. This dynamic damper is used to reduce vibration in the vehicle vertical direction (vertical direction) of a vehicle body-side member or the like. The resonance frequency is set.

[0003]

However, when the resonance frequency of the dynamic damper with respect to the vehicle vertical direction (vertical direction) is set to a low frequency of 100 Hz or less, the shearing direction of the connecting portion 3 (see FIG. 5). The spring characteristic (in the left-right direction) becomes low (soft), and the mass fitting 2 tends to swing in the left-right direction. Therefore, there is a problem that the durability of the connecting portion 3 made of a rubber elastic body is reduced. In addition, the swinging of the mass fitting 2 tends to cause interference between the mass fitting 2 and a surrounding member provided therearound, and may possibly damage the mating member. Further, when the swing of the mass metal fitting 2 becomes remarkable, it becomes difficult to attach the falling prevention pin 4 for preventing the mass metal fitting 2 from falling off and to the mounting metal fitting and the mass metal fitting.

An object of the present invention is to provide a dynamic damper capable of softening a spring characteristic of a rubber elastic body in a vehicle vertical direction (vertical direction) and suppressing a swing of a mass metal fitting. With the goal.

[0005]

In order to achieve the above-mentioned object, the structural feature of the present invention according to the first aspect is characterized in that an inner cylinder and a concentrically disposed outside the inner cylinder. The outer cylinder, and the inner cylinder and the outer cylinder are disposed between facing surfaces of the inner cylinder and the outer cylinder, and the inner cylinder and the outer cylinder are elastically connected at a central portion in the axial direction, and at a plurality of positions in the circumferential direction. A rubber bush provided with a rubber elastic body having a through hole penetrating in the axial direction, and a cylindrical shape fixed to an outer circumferential side concentric position of the outer cylindrical member by press-fitting the outer cylindrical member of the rubber bush into the center hole. With the mounting bracket member, which is inserted into the shaft hole of the inner cylindrical fitting,
At one end of the inner cylinder, the shaft is fixed to a mounting part of a vehicle or the like so that the axial direction thereof is vertical. An annular washer member having an outer diameter equal to or larger than the inner diameter of the fitting is locked to the mounting shaft member. The fixing to the mounting portion of the vehicle or the like may be either directly fixing to a mating member such as a vehicle body member or indirect fixing through a flat mounting member attached to the mating member. Applicable.

According to the first aspect of the present invention, the rubber elastic body has a plurality of through-holes penetrating in the axial direction, and the inner and outer cylinders are formed substantially at the center in the axial direction. Are connected, vibration in the shear direction is applied to the connection portion, and the spring characteristics in the axial direction are softened. In addition, since the mass metal fitting is arranged symmetrically in the direction perpendicular to the axis with respect to the axis, and the connecting portion of the rubber elastic body is provided at the axial center portion of the mass metal fitting, vibration in the swinging direction can be suppressed. it can. Therefore, the durability of the rubber elastic body is not impaired. Further, since the dynamic damper is suppressed in swinging motion and is cantilevered, the mounting space thereof can be reduced. Also, with respect to the detachment of the mass fitting due to damage to the rubber elastic body, the detachment can be reliably prevented by providing the annular washer member.

A structural feature of the invention according to claim 2 is that the through holes are arranged at equal intervals at three places in the circumferential direction. Thus, by providing three through holes at equal circumferential positions of the rubber elastic body, the rubber elastic body acts evenly against radial vibrations from any position in the circumferential direction. become.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a dynamic damper attached to a vehicle body-side member supporting an engine of an automobile according to the embodiment. It is shown by a direction sectional view and a plan view.

This dynamic damper is composed of an inner cylinder 1
1, a rubber bush 10 made of a rubber elastic body 13 for elastically connecting an outer cylinder fitting 12 and both fittings, a cylindrical mass fitting 20 fitted on the outer peripheral surface of the outer cylinder fitting, and an inner cylinder fitting 11
A flat mounting bracket 30 attached to one end of the inner cylinder fitting 11 by a bolt 22 inserted into the inner cylinder fitting 11 and a nut 23 screwed to the tip of the bolt. An annular washer member 25 is provided between the nut 23 and the end of the inner cylinder fitting 11.

The inner tube fitting 11 is a thick pipe made of metal. The outer cylinder fitting 12 is a thin metal pipe having an axial length slightly shorter than the inner cylinder fitting 11 and an inner diameter slightly larger than the outer diameter of the inner cylinder fitting 11. Is disposed axially symmetrically and coaxially at a predetermined distance in the radial direction between both ends in the axial direction.

The rubber elastic body 13 is integrally formed between the opposing surfaces of the inner cylindrical fitting 11 and the outer cylindrical fitting 12 by rubber vulcanization bonding. As shown in FIG. 3 and FIG. The bush 10 is constituted. The rubber elastic body 13
A thin inner rubber portion 14 provided on the outer peripheral surface of the inner cylindrical fitting 11 except for both ends in the axial direction, and three circumferentially equally spaced portions between the outer peripheral surface of the inner rubber portion 14 and the inner peripheral surface of the outer cylindrical fitting 12. It has three connecting portions 15 that are spread at a predetermined angle in the circumferential direction and are arranged in a predetermined range at the center in the axial direction. Therefore, both sides in the axial direction of each connecting portion 15 are spaces, and three through holes 16 penetrating between both ends in the circumferential direction are provided between the connecting portions 15 in the circumferential direction. Thus, the rubber elastic body 13
By providing the through-holes 16 in the rubber member, it is possible to avoid a problem that water, dust, and the like accumulate in the rubber elastic body portion and the durability is impaired.

The mass metal fitting 20 is a thick cylindrical metal fitting whose inner diameter is slightly smaller than the outer diameter of the outer cylindrical metal fitting 12 and whose axial length is equal to or less than the axial length of the outer cylindrical metal fitting 12. Has been slightly larger. By press-fitting the outer cylinder 12 of the rubber bush 10 into the mass metal 20, the mass metal 20 is fixed to the outer peripheral surface of the outer cylinder 12 in close contact.

The bolt 22 has an outer diameter of a shaft portion 22a substantially equal to an inner diameter of the inner cylindrical metal fitting 11, a head 22b at one end, and a screw portion 22c at the other end. The bolt 22 is inserted into the shaft hole 11a of the inner cylinder fitting 11 from one end thereof, and its screw portion 22c projects from the other end, and the nut 23 is screwed into the screw portion 22c. I have.

The mounting bracket 30 is a symmetrical plate-shaped metal bracket formed by rounding the tops of a rhombus into an arc shape. One center line orthogonal to each other is approximately twice as large as the other center line. It is length. One mounting hole 31 is provided at a position near both ends on the center line on the long side. In the central part of the mounting bracket 30, a circular part having a diameter slightly shorter than the length of the center line on the short side is a convex part 33 bulging from the plate surface to one surface side in parallel with the plate surface. . The protrusion 33 is
The outer peripheral portion is an inclined portion 33a inclined approximately 45 ° toward the center side, and the inside of the inclined portion 33a is a circular flat portion 33b.
It has become. A center hole 33c is provided at the center of the circular flat portion 33b. The opposite surface side of the projection 33 is
It is a relatively concave portion 34, and on the concave portion 34 side,
The bolt 22 is inserted into the center hole 33c, the shaft portion 22a protrudes perpendicularly to the plane toward the convex portion 33, and the head portion 22b is fixed to the concave portion 34 by welding.
The head 22b has a height smaller than the depth of the concave portion 34 and is housed in the concave portion 34 so as not to protrude from the other surface side.

The inner diameter of the washer member 25 is
The inner diameter is slightly larger than the inner diameter and the outer diameter is equal to the inner diameter of the outer cylinder fitting 12 or slightly smaller than the outer diameter of the outer cylinder fitting 12. It is externally inserted into the screw portion 22c at the tip, is fastened to a nut 23 screwed to the screw portion 22c, and is clamped and fixed to the other end of the inner cylinder fitting 11.

This dynamic damper is fixed with bolts and nuts and the like by aligning a pair of mounting holes 31 of a mounting bracket 30 with mounting holes of a vehicle body side member (not shown) that supports an engine of the vehicle. Thereby, the dynamic damper is cantilevered by the vehicle body side member.

As described above, in the above embodiment, the rubber elastic body 13 is provided with three through holes 16 penetrating in the axial direction, and the inner cylindrical metal fitting is formed at a substantially central portion in the axial direction. Since the connecting portion 15 that connects the outer tube fitting 11 to the outer tube fitting 12 is provided, the connecting portion 1 is connected to an axial vibration input.
In the case of 5, vibration is applied in the shearing direction, so that the axial spring characteristics are softened. As a result, it is possible to effectively attenuate the vibration input propagating from the vehicle body-side member, particularly in a frequency range lower than 100 Hz. Further, since the mass fitting 20 is symmetrically arranged in the direction perpendicular to the axis with respect to the axis, and the connecting portion 15 is provided at the axial center of the mass fitting 20, the mass fitting 20 is not affected by radial vibration. Can be suppressed. As a result, the durability of the rubber elastic body 13 is not impaired. In addition, since the swing of the mass fitting 20 can be suppressed, damage to peripheral members due to interference with the mass fitting 20 can be prevented.

Furthermore, since the dynamic damper has a suppressed swinging motion and is cantilevered,
The mounting space can be reduced. In addition, when the mass metal fitting 20 is detached from the inner cylindrical metal fitting 11 due to the breakage of the rubber elastic body 13 or the like, the detachment can be reliably prevented by providing the washer member 25.

The rubber elastic body 13 is provided with three through holes at evenly spaced positions in the circumferential direction, so that the rubber elastic body 1 can withstand radial vibration from any position in the circumferential direction.
The result is to act equally on 3. Therefore, there is no need to consider the direction of attachment of the rubber bush to the attachment fitting 30, and the attachment work can be facilitated. However, the number of the through holes 16 is not limited to three and may be four or more. Also, the intervals between the through holes 16 need not necessarily be equal.

The resonance frequency characteristic of the dynamic damper shown in the above embodiment can be changed to a desired frequency range by changing the shape and weight of the mass fitting or the shape and type of the rubber elastic body. Can be adjusted. Further, in the above embodiment, the bolt is fixed to the mounting bracket by welding, but instead of this, a nut is fixed to the mounting bracket, and a bolt is inserted from the other end of the inner cylindrical fitting to attach the rubber bush to the mounting bracket. You may make it fix.

Further, in the above embodiment, the rubber bush 10 can be directly mounted on the mating member without using the mounting bracket 30. Further, the dynamic damper of the present invention can be used not only for vehicles but also for other similar uses. In addition, the dynamic damper described in the above embodiment is an example, and can be implemented in various forms without departing from the gist of the present invention.

[0022]

According to the first aspect of the present invention, since the vibration in the shear direction is applied to the connecting portion of the rubber elastic body, the spring characteristic in the axial direction is softened. Can be attenuated. Further, since the mass metal fitting is arranged symmetrically in the direction perpendicular to the axis with respect to the axis, and the connecting portion is provided at the axial center of the mass metal fitting, vibration in the swinging direction can be suppressed. As a result, the durability of the rubber elastic body is not impaired. In addition, the provision of the washer member can reliably prevent the mass metal fitting from coming off due to damage to the rubber elastic body. Further, by providing the through hole in the rubber elastic body, it is possible to avoid a problem that water and dust accumulate in the rubber elastic body portion. In addition, by providing three through holes at equal intervals in the circumferential direction, the directivity to radial vibration is eliminated, so that there is no need to perform positioning when mounting the rubber bush on the mounting portion side. The workability is enhanced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along a line II of FIG. 2 showing a dynamic damper according to an embodiment of the present invention.

FIG. 2 is a plan view showing a dynamic damper.

FIG. 3 shows a rubber bush of a dynamic damper.
FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 is a plan view showing the rubber bush.

FIG. 5 is a front view showing a conventional dynamic damper.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... rubber bush, 11 ... inner cylinder fitting, 12 ... outer cylinder fitting, 13 ... rubber elastic body, 15 ... connection part, 16 ... through-hole,
Reference numeral 20: mass fitting, 22: bolt 23, nut, 25: washer member, 30: mounting fitting, 31: mounting hole, 33: convex part.

Claims (2)

[Claims] 1. An inner cylinder, an outer cylinder concentrically disposed outside the inner cylinder, and an axial center disposed between opposing surfaces of the inner cylinder and the outer cylinder. A rubber bush having a rubber elastic body having a through hole that elastically connects between the inner and outer cylinder fittings at a plurality of locations and penetrates in a plurality of locations in a circumferential direction in an axial direction; A cylindrical mass fitting fixed at a position concentric to the outer peripheral side of the outer cylindrical fitting by press-fitting the outer cylindrical fitting into the center hole, and a mounting shaft inserted into a shaft hole of the inner cylindrical fitting. The member is supported on the mounting portion by being fixed to a mounting portion of a vehicle or the like so that the axial direction thereof is vertical at one end side of the inner cylindrical metal fitting, while the other end of the inner cylindrical metal fitting is supported. On the side, a washer member having an outer diameter equal to or greater than the inner diameter of the outer cylindrical fitting is locked to the mounting shaft member. Dynamic damper according to claim. 2. The rubber bush according to claim 1, wherein the through holes are provided at three positions in a circumferential direction at equal intervals.