JP2006177525A - Cylindrical dynamic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical dynamic damper having two different resonant frequencies, capable of being tuned in a state of largely separating two resonant frequencies from each other. <P>SOLUTION: A rubber elastic supporting member 3 mounted between an intermediate cylindrical member 1 and a mass member 2 for elastically supporting the mass member 2, is constituted so that constants of spring in two directions (P-direction and Q-direction) orthogonal to each other on an axis L on a plane perpendicular to the axis L of the intermediate cylindrical member 1 are different from each other, and a pair of first bore holes 31, 31 for adjusting the constants of spring are formed in a state of being axially penetrated on positions axially symmetric to each other through the intermediate cylindrical member 1 in the P-direction of the rubber elastic supporting member 3. A pair of second bore holes 32, 32 for adjusting the constants of springs, smaller than the first bore holes 31, 31 and axially penetrated, are formed positions axially symmetric to each other through the intermediate cylindrical member 1 in the Q-direction of the rubber elastic supporting member 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cylindrical dynamic damper that is attached to a rotating shaft such as a drive shaft or a propeller shaft of an automobile and suppresses harmful vibrations generated on the rotating shaft.

  Because the drive shafts and propeller shafts equipped in automobiles generate harmful vibrations that should not occur originally, such as bending vibrations and torsional vibrations due to rotational unbalance caused by the rotation. In order to suppress the harmful vibration, various dynamic dampers as disclosed in Patent Documents 1 to 5, for example, are used. This dynamic damper matches the resonance frequency (natural frequency) with the dominant frequency of harmful vibrations excited on the rotating shaft, thereby converting the vibration energy of the rotating shaft into the vibration energy of the dynamic damper by resonance and absorbing it. It fulfills its function.

  As such a dynamic damper, for example, in Patent Documents 1 and 2, a cylindrical mass member that is fitted and disposed on the outer peripheral side of a rotating shaft, and a taper that elastically supports both axial ends of the mass member in a shearing direction. A cylindrical dynamic damper having a pair of cylindrical elastic elastic support members is disclosed. The rubber elastic support member of the dynamic damper is formed by changing the thickness and the axial length thereof, and the high spring portion in which the spring constant in the shear direction is set higher than the specific value and the specific value. The low spring portions are set low, and the high spring portions and the low spring portions are alternately arranged in the circumferential direction. As a result, by tuning the resonance frequency of the dynamic damper to two different resonance frequencies, it is possible to minimize the reduction in the vibration suppression effect caused by variations in the resonance frequency of the rotating shaft and the dynamic damper. The resonance frequency of the dynamic damper is basically determined by the mass of the mass member and the spring constant in the shear direction of the rubber elastic support member.

  By the way, it is known that harmful vibrations are excited by a vibration transmitted through the wheel of a wheel on a rotating shaft such as a drive shaft installed in an automobile. Therefore, when tuning the resonance frequency of the dynamic damper attached to these rotating shafts, the resonance frequency (natural frequency) of the wheel must also be taken into consideration. However, normally used wheels are roughly divided into iron and aluminum, but the resonance frequency of the iron wheel and the resonance frequency of the aluminum wheel are far apart, and the resonance frequency of the aluminum wheel is It becomes about 2 to 3 times the resonance frequency of the iron wheel.

For this reason, in the dynamic damper of the type disclosed in Patent Documents 1 and 2, the high and low spring portions of the rubber elastic support member are used to tune the two resonance frequencies for the iron wheel and the aluminum wheel. Is configured to elastically support the mass member in the shear direction, so that even if the thickness and free length thereof are adjusted to the maximum, the resonance frequency on the high frequency side is one of the resonance frequencies on the low frequency side. Tuning to about 5 times is the limit.
JP-A-9-89047 Japanese Patent Laid-Open No. 2004-92674 JP-A-9-229137 Japanese Utility Model Publication No. 6-69487 JP 2002-266939 A

  The present invention has been made in view of the above circumstances, and solves the problem of providing a cylindrical dynamic damper that has two different resonance frequencies and can be tuned with a greater separation between the two resonance frequencies. It should be a challenge.

  The present invention for solving the above problems is a cylindrical intermediate cylinder member having a thin rubber fixed to the inner peripheral surface, a cylindrical mass member disposed coaxially on the radially outer side of the intermediate cylinder member, A rubber-type elastic support member interposed between the intermediate cylinder member and the mass member to elastically support the mass member, and a cylindrical dynamic damper fitted into the outer periphery of the rotary shaft by press-fitting, The rubber elastic support member is configured so that spring constants in two directions orthogonal to each other on the axis are different on a plane perpendicular to the axis of the intermediate cylinder member.

  In the cylindrical dynamic damper of the present invention, the rubber elastic support member is configured so that the spring constants in two directions orthogonal to each other on a plane perpendicular to the axis of the intermediate cylinder member are different from each other. It is tuned to have two different resonant frequencies based on the directional spring constant. Since the rubber elastic support member in the present invention is configured to elastically support the mass member in a state where compression is applied in the radial direction, the spring ratio in two directions is more than that in the case of elastically supporting the mass member in the shear direction. Can be made larger. Therefore, it is possible to tune so that one has two resonance frequencies that are far apart so that one is about three times the other.

  Further, since the rubber elastic support member in the present invention is interposed between the intermediate cylinder member and the mass member, when the cylindrical dynamic damper is fitted on the outer periphery of the rotation shaft by press fitting, the rotation shaft The influence due to the variation in diameter and the like is surely blocked by the intermediate cylinder member. Therefore, a compression component is not added to the rubber elastic support member, and variation in characteristics of the rubber elastic support member at the time of assembly is surely eliminated, so that variation tolerance can be reduced.

  In the present invention, in order to configure the rubber elastic support member so that the spring constants in the two directions orthogonal to each other on the plane perpendicular to the axis of the intermediate cylinder member are different, at least one of the two directions. This can be achieved by providing a straight hole for adjusting the spring constant penetrating in the axial direction in a portion that is axially symmetric with respect to the intermediate cylinder member. In this case, a pair or a plurality of tickling holes may be provided only in one direction, or a pair or a plurality of tickling holes may be provided in both of the two directions. In the case of providing in both directions, the size of the tick hole is made different in one direction and the other direction, whereby the spring constants in the two directions are made different. The size of the straight hole can be changed by a straight angle or a cross-sectional area in the circumferential direction around the axis of the intermediate cylinder member. The two-way spring constant of the rubber elastic support member is appropriately set in relation to the mass of the mass member when tuning the two resonance frequencies of the cylindrical dynamic damper.

  The rubber elastic support member in the present invention is disposed so as to elastically support the mass member interposed between the intermediate cylinder member and the mass member. The intermediate cylinder member is formed in a cylindrical shape using, for example, iron-based or aluminum-based metal, and has a thin rubber fixed to the inner peripheral surface thereof. The thin rubber is provided to absorb the press-fitting allowance when the cylindrical dynamic damper is attached to the rotary shaft by press-fitting. This thin rubber is configured to have a plurality of ridges that protrude radially inward from the inner peripheral surface of the intermediate cylindrical member and extend in the axial direction, thereby adjusting the press-fitting allowance and facilitating the press-fitting operation. can do.

  The mass member is formed in a cylindrical shape so as to have a predetermined mass in relation to the spring constant in the two compression directions of the rubber elastic support member. This mass member is preferably formed so that the mass is uniform in the circumferential direction in order to keep the balance in the circumferential direction uniform. For the formation of the mass member, an iron-based metal having a large specific gravity can be suitably employed.

  In the cylindrical dynamic damper of the present invention, a rubber elastic support member interposed between the intermediate cylinder member and the mass member and elastically supporting the mass member in the compression direction has an axis on a plane perpendicular to the axis of the intermediate cylinder member. Since the spring constants in the two directions orthogonal to each other are different, the spring ratio in the two directions can be set larger, so that the two resonance frequencies have two different resonance frequencies. The frequency can be tuned farther away.

  In addition, since the rubber elastic support member in the present invention is interposed between the intermediate cylinder member and the mass member, the intermediate cylinder member can reliably block the influence due to the variation in the diameter of the rotating shaft. Therefore, the characteristic variation of the rubber elastic support member at the time of assembly can be surely eliminated, and the variation tolerance can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of the cylindrical dynamic damper according to the present embodiment as viewed from the axial direction, and FIG. 2 is a cross-sectional view of the cylindrical dynamic damper along the axial direction, taken along line II-II in FIG. It is sectional drawing.

  As shown in FIGS. 1 and 2, the cylindrical dynamic damper of the present embodiment includes a cylindrical intermediate cylinder member 1 having a thin rubber layer 11 fixed to an inner peripheral surface, and a radially outer side of the intermediate cylinder member 1. The cylindrical mass member 2 is arranged coaxially therewith, and the rubber elastic support member 3 is interposed between the intermediate cylinder member 1 and the mass member 2 to elastically support the mass member 2.

  The intermediate cylinder member 1 is formed in a cylindrical shape with a substantially constant thickness from an iron-based metal. The intermediate cylinder member 1 has a substantially constant inner diameter that is a predetermined dimension larger than the outer diameter of the rotating shaft on which the cylindrical dynamic damper is mounted. A thin rubber layer 11 formed in a thin and substantially cylindrical shape is fixed to the inner peripheral surface of the intermediate cylinder member 1 by vulcanization adhesion so as to cover the entire inner peripheral surface. On the inner peripheral surface of the thin rubber layer 11, a plurality of protrusions 12 projecting radially inward and extending in the axial direction are provided at a predetermined distance in the circumferential direction. Further, a coated rubber layer 13 formed integrally with the thin rubber layer 11 by vulcanization molding is fixed to a surface other than the inner peripheral surface of the intermediate cylinder member 1 for rust prevention.

  The mass member 2 includes a mass body 21 formed of a ferrous metal in a cylindrical shape having a substantially constant thickness and a substantially constant diameter, and a covering rubber layer 22 that covers the surface of the mass body 21. Have mass. The mass member 2 has an inner diameter that is larger than the outer diameter of the intermediate cylinder member 1 by a predetermined dimension, and is formed about 1.6 times as long as the intermediate cylinder member 1. The mass member 2 is coaxially disposed at a position where the center in the axial direction substantially coincides with the center in the axial direction of the intermediate cylinder member 1 and spaced radially outside the intermediate cylinder member 1 by a predetermined distance.

  The rubber elastic support member 3 is formed by placing the intermediate cylinder member 1 and the mass member 2 coaxially in the vulcanization molding die as described above, and vulcanizing and molding the rubber material together with the two members. It is formed in a substantially thick cylindrical shape so as to be interposed between the member 1 and the mass member 2. When the rubber elastic support member 3 is vulcanized and molded, the thin rubber layer 11 and the covering rubber layers 13 and 22 are simultaneously formed integrally with the rubber elastic support member 3. Further, at the time of vulcanization molding, since the mass member 2 arranged in the vulcanization mold is supported by the positioning support pins, the covering rubber layer 22 that covers the surface of the mass member 2 is provided with a concave portion by the support pins. 22a is formed at a plurality of locations.

  The inner peripheral surface side of the rubber elastic support member 3 is integrally connected to the covering rubber layer 13 and is vulcanized and bonded to the outer peripheral surface of the intermediate cylinder member 1, and the outer peripheral surface side of the rubber elastic support member 3 is the covering rubber. It is integrally connected to the layer 22 and vulcanized and bonded to the inner peripheral surface of the mass member 2. The rubber elastic support member 3 has an axial length shorter than that of the intermediate cylinder member 1 and is provided at a position where the center in the axial direction substantially coincides with the center in the axial direction of the intermediate cylinder member 1. Thereby, the rubber elastic support member 3 is provided so as to elastically support the mass member 2 in a state where compression acts in the radial direction.

  As shown in FIG. 1, the rubber elastic support member 3 has different spring constants in two directions (P direction and Q direction) perpendicular to the axis L on a plane perpendicular to the axis L of the intermediate cylindrical member 1. It is configured. That is, a pair of first straight holes 31, 31 penetrating in the axial direction and having an arc-shaped cross section are provided in a portion that is axially symmetric with respect to the intermediate cylindrical member 1 in the P direction, and an intermediate in the Q direction. A pair of second straight holes 32, 32 penetrating in the axial direction and having a circular cross section are provided in a portion that is axially symmetric with respect to the cylindrical member 1.

  The first straight holes 31, 31 and the second straight holes 32, 32 have the same radial width, but the first straight holes 31, 31 have a second length extending in an arc shape in the circumferential direction. It is longer than the straight holes 32, 32. That is, the first straight holes 31 and 31 have the first straight holes 31 and 31 that are larger in the circumferential direction around the axis L than the second straight holes 32 and 32. The holes 31 and 31 have a larger cross-sectional area than the second straight holes 32 and 32. As a result, the spring constant in the P direction in which the first straight holes 31 and 31 are provided is adjusted to be greatly reduced, and the spring constant in the Q direction in which the second straight holes 32 and 32 are provided is reduced to a small value. Have been adjusted so that.

  The spring constant in the P direction is appropriately set in relation to the mass of the mass member 2 when tuning the resonance frequency f1 in the P direction as a resonance frequency on the low frequency side for an iron wheel, for example. The spring constant in the Q direction is appropriately set in relation to the mass of the mass member 2 when tuning the resonance frequency f2 in the Q direction as a resonance frequency on the high frequency side for an aluminum wheel, for example. In this way, the elastic elastic support member 3 is configured so that the spring constants in the two directions of the P direction and the Q direction are different, so that two different resonance frequencies f1 and f2 at which the cylindrical dynamic damper is greatly separated can be obtained. It is comprised so that it may have. In the present embodiment, the ratio between the resonance frequency f1 and the resonance frequency f2 is 1: 2.

  As shown in FIG. 3, the cylindrical dynamic damper of the present embodiment configured as described above is press-fitted using a jig or the like from the shaft end of the rotating shaft 5 such as a drive shaft of an automobile and the rotating shaft 5. The protruding portion 12 of the thin rubber layer 11 provided on the inner peripheral surface of the intermediate cylinder member 1 is attached to a predetermined portion of the outer peripheral surface (usually a portion that becomes the belly of the central portion in the axial direction). . In addition, in the dynamic damper of the type disclosed in Patent Documents 1 and 2, special fixing means such as a fixing band and a clamp are necessary for fixing to a rotating shaft such as a drive shaft. The cylindrical dynamic damper can be firmly fixed to a rotating shaft such as a drive shaft without separately providing special fixing means as described above.

  When harmful vibrations such as bending vibrations and torsional vibrations are excited as the rotating shaft 5 rotates, vibrations having frequencies close to the two resonance frequencies f1 and f2 tuned to the cylindrical dynamic damper are generated. The mass member 2 of the cylindrical dynamic damper resonates mainly through the compressive deformation or tensile deformation in the radial direction of the rubber elastic support member 3, so that the vibration energy of the rotating shaft 5 is absorbed and the harmfulness excited by the rotating shaft 5 Vibration is effectively suppressed.

  At this time, when an aluminum wheel is used for the wheel of the automobile, vibration having a frequency close to the resonance frequency f1 tuned based on the spring constant in the P direction of the rubber elastic support member 3 is used for the aluminum wheel. Is excited, harmful vibrations transmitted to the rotary shaft 5 through the aluminum wheel are effectively suppressed by the cylindrical dynamic damper. Further, when an iron wheel is used for an automobile wheel, a vibration having a frequency close to the resonance frequency f2 tuned based on the spring constant in the Q direction of the rubber elastic support member 3 is excited for the iron wheel. Therefore, the harmful vibration transmitted to the rotating shaft 5 through the iron wheel is also effectively suppressed by the cylindrical dynamic damper.

  As described above, the cylindrical dynamic damper according to the present embodiment includes the rubber elastic support member 3 interposed between the intermediate cylindrical member 1 and the mass member 2 and elastically supporting the mass member 2 in the compression direction. Since the spring constants in the two directions of the P direction and the Q direction orthogonal to each other on the axis L on the right-angle plane are different, the spring ratio in the P direction and the Q direction can be set larger. Therefore, it can be tuned to have two different resonance frequencies f1 and f2 based on the spring constants in the P direction and the Q direction, and the two resonance frequencies f1 and f2 can be tuned further apart. .

  Further, since the rubber elastic support member 3 is interposed between the intermediate cylinder member 1 and the mass member 2, the intermediate cylinder member 1 can reliably block the influence due to variations in the diameter of the rotating shaft 5. Therefore, variation in characteristics of the rubber elastic support member 3 during assembly can be surely eliminated, and variation tolerance can be reduced.

  Moreover, in this embodiment, since the some protruding part 12 extended in an axial direction is provided in the internal peripheral surface of the thin rubber layer 11 fixed to the internal peripheral surface of the intermediate cylinder member 1, a cylindrical dynamic damper is provided. Since the protrusion 12 is easily elastically deformed and the press-fitting allowance is absorbed when the press-fitting is inserted into the outer periphery of the rotary shaft 5, the press-fitting operation can be easily performed. In addition, although the protrusion part 12 in this embodiment is provided in the inner peripheral surface of the thin rubber layer 11, only the protrusion part 12 is provided in the inner peripheral surface of the intermediate cylinder member 1, without providing the thin rubber layer 11. You may make it provide directly.

  In the above embodiment, a total of four first and second straight holes 31, 31, 32, 32 are provided in each of the two directions of the P direction and the Q direction. In order to make the constants different, it is only necessary to provide a pair or a plurality of pairs of straight holes in at least one of the two directions, and various combinations can be selected.

  For example, the cylindrical dynamic damper shown in FIG. 4 has the above-described implementation in the P direction of the two directions (P direction and Q direction) orthogonal to each other on the axis L at a portion that is axially symmetric with respect to the intermediate cylindrical member 1. A pair of first straight holes 31a, 31a similar to the form are provided. However, in the Q direction, two pairs of second straight holes 32a, 32a, 32a, and 32a are provided in portions that are axially symmetric with respect to the intermediate cylinder member 1. The second straight holes 32a, 32a, 32a, and 32a have a curb formation angle θ in the circumferential direction centered on the axis L that is reduced to about 1/6 of the straight formation angle α of the first straight holes 31a and 31a. Yes. Accordingly, the spring constant in the P direction in which the first straight holes 31a and 31a are provided is adjusted to be greatly reduced, and the spring constant in the Q direction in which the second straight holes 32a, 32a, 32a and 32a are provided. Has been adjusted to be reduced.

  Further, the cylindrical dynamic damper shown in FIG. 5 has a portion that is axially symmetric with respect to the intermediate cylindrical member 1 in the P direction of two directions (P direction and Q direction) orthogonal to each other on the axis L. A pair of first straight holes 31b, 31b similar to those of the embodiment are provided, but no straight holes are provided in the Q direction. In this case, the spring constant in the P direction in which the first straight holes 31b and 31b are provided is adjusted to be greatly reduced, whereas the spring constant in the Q direction is adjusted to be reduced. This is advantageous when the spring ratio in the P direction and the Q direction is set larger.

It is the front view seen from the axial direction of the cylindrical dynamic damper concerning the embodiment of the present invention. It is sectional drawing which follows the axial direction of the cylindrical dynamic damper which concerns on embodiment of this invention, Comprising: It is the II-II sectional view taken on the line of FIG. It is sectional drawing which shows the state which attached the cylindrical dynamic damper which concerns on embodiment of this invention to the drive shaft. It is the front view seen from the axial direction of the cylindrical dynamic damper concerning other embodiments of the present invention. It is the front view seen from the axial direction of the cylindrical dynamic damper concerning other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Intermediate | middle cylinder member 2 ... Mass member 3 ... Rubber elastic support member 5 ... Rotating shaft 11 ... Thin rubber layer 12 ... Projection part 13 ... Cover rubber layer 21 ... Mass body 22 ... Cover rubber layer 22a ... Recess 31,31a, 31b ... 1st straight hole 32, 32a ... 2nd straight hole

Claims (4)

A cylindrical intermediate cylinder member having a thin rubber fixed to the inner peripheral surface, a cylindrical mass member arranged coaxially on the radially outer side of the intermediate cylinder member, the intermediate cylinder member and the mass member, A rubber elastic support member that elastically supports the mass member interposed therebetween, and is a cylindrical dynamic damper that is fitted into the outer periphery of the rotating shaft by press fitting,
The cylindrical elastic damper is characterized in that the rubber elastic support member is configured to have different spring constants in two directions orthogonal to each other on a plane perpendicular to the axis of the intermediate cylinder member.   The rubber elastic support member is provided with a straight hole for adjusting a spring constant penetrating in an axial direction at a portion that is axially symmetric with respect to the intermediate cylindrical member in at least one of the two directions. The cylindrical dynamic damper according to 1.   3. The cylindrical dynamic damper according to claim 2, wherein a pair of the straight holes are provided in each of the two directions, and a straight forming angle in a circumferential direction around the axis is different in the two directions. .   4. The cylindrical dynamic damper according to claim 1, wherein the thin rubber has a plurality of protrusions protruding radially inward from an inner peripheral surface of the intermediate cylindrical member and extending in an axial direction.

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