JP4026609B2 - Cylindrical dynamic damper - Google Patents

Description

  The present invention relates to a cylindrical dynamic damper that is attached to a mating member such as a tube in a vehicle seat and attenuates vibration generated on the mating member side.

Conventionally, as this type of cylindrical dynamic damper, for example, as shown in Patent Document 1, a round bar-shaped mass body and a plurality of ring-shaped elastic members bonded to the outer peripheral surface side of the mass body are provided. It is known that the elastic member is attached to the propeller shaft damper mounting portion in a state where the outer peripheral surface of the elastic member is in contact with the inner peripheral surface of the propeller shaft by being press-fitted into the hollow portion of the propeller shaft. Further, the document includes a cylindrical fixing bracket, a round bar-shaped mass body arranged on the inner peripheral surface side of the fixing bracket, and an elastic member that connects between the mass body and the fixing bracket. A dynamic damper mounted in the hollow portion of the propeller shaft is disclosed in which the outer peripheral surface of the fixing bracket and the inner peripheral surface of the cylindrical wall of the damper mounting portion of the propeller shaft are brought into close contact with each other by press-fitting into the hollow portion of the propeller shaft. . This dynamic damper attenuates harmful harmful vibrations in the radial direction such as bending vibration and torsional vibration caused by rotation of the propeller shaft.
ACT 2-103543

  However, any of the above-described cylindrical dynamic dampers attenuates vibrations in the radial direction by compressing and deforming the elastic member in the radial direction, and the resonance frequency becomes high. Is suitable, but it has been difficult to attenuate low frequency vibrations.

  An object of the present invention is to provide a cylindrical dynamic damper capable of attenuating low-frequency radial vibrations.

  In order to achieve the above object, the structural features of the present invention include a cylindrical fitting attached to a mating member, and an inner wall surface of the cylindrical fitting that is bonded to the inner wall surface of the cylindrical fitting. A cylindrical rubber elastic body provided with a locking portion which is a convex portion projecting radially inward from at least a part or a concave portion recessed radially outward, and a rod shape inserted and disposed in a shaft hole of the rubber elastic body Which is a concave portion recessed inward in the radial direction or a convex portion protruding outward in the radial direction at a position corresponding to the engaging portion on the outer peripheral surface thereof, and facing each other at both axial ends. An engaging portion having an inclined surface inclined at a predetermined angle and an inner surface sandwiched between the inclined surfaces is provided, and is engaged with the engaging portion and supported by the rubber elastic body at the engaging portion. A mass fitting, and the inclined surface of the mass fitting is in radial contact with both axial sides of the rubber elastic body. In that the gap is provided between an outer peripheral surface of the inner peripheral surface and the mass metal of the rubber elastic body opposing non part pressed.

  In the invention configured as described above, the mass fitting inserted and disposed in the rubber elastic body has the engaging portion locked to the locking portion of the rubber elastic body, and the mass metal fitting is inclined. The surface is in radial contact with both sides in the axial direction of the engaging portion of the rubber elastic body, and there is a gap between the inner peripheral surface of the rubber elastic body and the outer peripheral surface of the mass metal fitting that are opposed to each other except the press-contact portion. Is provided. In this manner, the mass metal fitting is pressed against both sides in the axial direction of the rubber elastic body at the inclined surface, so that the rubber elastic body is deformed not only in the compression direction but also in the shearing direction against the vibration in the radial direction of the mass metal fitting. Therefore, the spring characteristic of the rubber elastic body is softened. As a result, according to the present invention, the resonance frequency of the dynamic damper is set to a low frequency, and the low-frequency vibration in the radial direction of the counterpart member can be effectively suppressed.

  Further, in the present invention, the engaging portion of the rubber elastic body may have a pair of inclined surfaces inclined at a predetermined angle toward opposite directions at both ends in the axial direction and an inner surface sandwiched between the inclined surfaces. it can. Thereby, after shaping | molding of a rubber elastic body, extraction of the shaping | molding die from a shaft hole is performed smoothly. Further, the mass metal fitting can be smoothly inserted into the rubber elastic body. As a result, damage to the rubber elastic body is prevented.

  Moreover, in this invention, the axial cross-sectional shape of the part which contacts the engaging part of the mass metal fitting at least of the latching | locking part of a rubber elastic body can be made into circular arc shape. As a result, the contact area of the rubber elastic body with the mass metal fitting is reduced, so that the shear deformation of the rubber elastic body effectively occurs, thereby reliably reducing the resonance frequency of the dynamic damper.

  Moreover, in this invention, the latching | locking part of a rubber elastic body and the engaging part of a mass metal fitting can be made into the annular shape along the circumferential direction perimeter. Thus, since the engaging part of the rubber elastic body and the engaging part of the mass metal fitting have an annular shape along the entire circumference in the circumferential direction, the directionality when the mass metal fitting is inserted into the rubber elastic body is improved. Therefore, the workability of inserting the mass metal fitting into the rubber elastic body is improved.

  Moreover, in this invention, the dimension of the overlapping part of the radial direction of the latching | locking part of a rubber elastic body and the engaging part of a mass metal fitting can be 1-3 mm. If the dimension of the radial overlap between the engaging portion of the rubber elastic body and the engaging portion of the mass metal fitting is smaller than 1 mm, the engaging state of the engaging portion to the engaging portion becomes unstable, and the mass fitting is made of rubber. There is a risk of detachment from the state of locking to the elastic body. Further, when the size of the overlapping portion is larger than 3 mm, the overlapping portion is wasted and the radial dimension of the dynamic damper becomes larger than necessary. That is, by setting the size of the overlapping portion in the range of 1 mm to 3 mm, a stable locking state of the engaging portion to the locking portion can be obtained, and the metal fitting can be prevented from coming off from the rubber elastic body. Vibration damping effect is obtained. Further, since the radial dimension of the dynamic damper is not unnecessarily increased, it can be inserted into a thin mating member.

  Further, in the present invention, when the locking portion of the rubber elastic body is a convex portion, the axial length of the locking portion is made shorter than the axial length of other portions of the rubber elastic body, and the mass metal fitting is engaged. If the axial length of the part is shorter than the axial length of the other part of the mass metal fitting and the engaging part of the rubber elastic body is a recess, the axial length of the engaging part is set to the other part of the rubber elastic body. The axial length of the engaging portion of the mass metal fitting can be made longer than the axial length of the other part of the mass metal fitting. As described above, by adjusting the axial length of the engaging portion and the axial length of the engaging portion of the mass metal fitting engaged therewith according to the unevenness of the engaging portion of the rubber elastic body, the rubber elasticity The spring characteristics in the axial direction of the body can be softened, and deformation in the shear direction can be effectively generated in addition to the compression direction of the rubber elastic body. Therefore, according to the present invention, it is possible to effectively attenuate the low frequency vibration in the radial direction.

  According to the present invention, the inclined surface of the engaging portion of the mass metal fitting is in pressure contact with both axial sides of the engaging portion of the rubber elastic body, and the inner peripheral surface and the mass of the opposed rubber elastic body other than the pressure contacting portion. Since a clearance is provided between the outer peripheral surface of the metal fitting, shearing deformation occurs in addition to compression deformation in the radial elastic part of the mass metal fitting at the locking portion of the rubber elastic body. Is softened. As a result, in the present invention, since the resonance frequency of the dynamic damper is set to a low frequency, it is possible to effectively suppress the low-frequency vibration in the radial direction of the counterpart member.

Embodiments of the present invention will be described below with reference to the drawings.
1, 2, and 3 are cross-sectional views taken along a line II-II and a cross-section taken along a line II-II, illustrating a cylindrical dynamic damper that is inserted into a pipe provided on a vehicle seat according to the first embodiment. It is shown by the figure and the principal part expanded sectional view. The cylindrical dynamic damper 10 is bonded to the cylindrical outer cylinder fitting 11 and the inner wall surface of the outer cylinder fitting 11, and is radially inward along the entire circumferential direction at two locations on both end sides in the axial direction. A cylindrical rubber elastic body 13 provided with a pair of protruding annular locking projections (locking portions) 14, and a round bar-shaped mass metal fitting 17 inserted and disposed in the shaft hole of the rubber elastic body 13 are provided. Yes. The mass member 17 has a pair of annular engagement recesses (engagement portions) 18 that are recessed radially inward along the entire circumferential direction at a position corresponding to the locking projection 14 in the axial direction of the outer peripheral surface. And is supported by the rubber elastic body 13 by being engaged with the engagement protrusion 14 by the engagement recess 18.

  The rubber elastic body 13 is a cylindrical shape having the same axial length as the outer cylindrical fitting 11 vulcanized and bonded to the inner wall surface of the outer cylindrical fitting 11, and is approximately 1/3 of the entire axial length from both ends in the axial direction. At this position, the locking projection 14 protrudes from the inner peripheral surface. The locking projection 14 has an approximately isosceles trapezoidal cross-sectional shape in the axial direction, which includes an inner side surface 14a parallel to the axial direction and an inclined surface 14b inclined at about 45 ° to the center side of the inner side surface 14a on both sides in the axial direction. It has become. Furthermore, the surface which contacts the said engagement recessed part 18 of the boundary of the inner surface 14a and both the inclined surfaces 14b is the circular-arc-shaped curved surface 15, respectively. In the rubber elastic body 13, the axial length of the locking projection 14 is larger than the length between both locking projections 14 and the length between the locking projection 14 and both ends in the axial direction of the rubber elastic body 13. It is short enough. Further, since both end sides in the axial direction of the locking projections 14 are inclined surfaces 14b, the molding die is smoothly extracted from the shaft hole after the rubber elastic body 13 is molded. Moreover, the mass metal fitting 17 is smoothly inserted into the rubber elastic body 13. Therefore, damage to the rubber elastic body 13 is prevented.

  The mass fitting 17 is a round bar-like fitting in which the outer diameter of the outer peripheral surface 17a is slightly smaller than the inner diameter of the inner peripheral surface 13a of the rubber elastic body 13, and the axial length is slightly longer than the outer cylinder fitting 11. A pair of engaging recesses 18 that are recessed in the axial direction from the outer peripheral surface are provided at positions corresponding to the locking projections 14 of the rubber elastic bodies 13 on both sides. The engaging recess 18 includes a bottom surface (inner surface) 18a parallel to the axial direction, and an inclined surface 18b inclined at approximately 45 ° toward the center of the bottom surface 18a on both sides in the axial direction. It has a substantially isosceles trapezoidal shape. Further, in the mass fitting 17, the axial length of the engagement recess 18 is the same as that of the engagement projection 18 in the rubber elastic body 13, and the length between the pair of engagement recesses 18 and the engagement recess 18 and the mass fitting. It is sufficiently shorter than the length between 17 axial ends.

  As shown in FIG. 3, the mass metal member 17 is in pressure contact with the arcuate curved surface 15 of the locking projection 14 on the outer end side of both inclined surfaces 18 b over the entire circumference. In addition, a gap is provided between the inner peripheral surface 13a of the rubber elastic body 13 and the outer peripheral surface 17a of the mass metal member 17 and between the engaging convex portion 14 and the engaging concave portion 18 except for the contact portions thereof. ing. In this manner, the rubber elastic body 13 is pressed against the radially outer end side of the inclined surface 18b of the engagement recess 18 of the mass fitting 17 on the two arcuate curved surfaces 15 of the locking projection 14. The mass bracket 17 is supported. Here, the length of the overlapping portion in the radial direction between the locking convex portion 14 and the engaging concave portion 18 that are locked with each other is about 2 mm.

  In the first embodiment configured as described above, the mass fitting 17 inserted and arranged in the rubber elastic body 13 is locked to the locking convex portion 14 of the rubber elastic body 13 by the engagement concave portion 18. The inclined surfaces 18b of the mass fitting 17 are in pressure contact with the inclined surfaces 14b on both sides in the axial direction of the locking projection 14 along the circumferential direction, and the inner peripheral surfaces 13a ( A gap is provided between the inner surface 14a and the inclined surface 14b) and the outer peripheral surface 17a (including the bottom surface 18a and the inclined surface 18b) of the mass member 17. For this reason, the rubber elastic body 13 undergoes not only compression deformation but also shear deformation with respect to vibration in the radial direction of the mass metal member 17, so that its spring characteristics are softened. As a result, according to the first embodiment, since the resonance frequency of the dynamic damper 10 is set to a low frequency, it is possible to suppress the low-frequency vibration in the radial direction of the pipe in the seat in which the dynamic damper 10 is inserted by press fitting. it can.

  Moreover, in Example 1, since the latching convex part 14 of the rubber elastic body 13 which contacts the engagement recessed part 18 of the mass metal fitting 17 is a cross-section circular arc shape, the contact area with the mass metal fitting 17 of the rubber elastic body 13 Decrease. Therefore, since the shear deformation is effectively generated in the rubber elastic body 13 in addition to the compression deformation, the resonance frequency of the dynamic damper is reliably lowered. Furthermore, in Example 1, the engagement convex part 14 of the rubber elastic body 13 and the engagement concave part 18 of the mass metal fitting 17 are in the shape of a ring along the entire circumference in the circumferential direction, so that the rubber elastic body 13 enters. Since there is no directionality at the time of insertion of the mass metal fitting 17, the workability of inserting the mass metal fitting 17 into the rubber elastic body 13 is improved.

  Moreover, in Example 1, since the dimension of the overlapping portion in the radial direction of the engaging convex portion 14 of the rubber elastic body 13 and the engaging concave portion 18 of the mass metal member 17 is set to approximately 2 mm, the engaging convex portion of the engaging concave portion 18 is set. A stable locking state to the portion 14 is ensured. Therefore, the mass metal member 17 is prevented from coming off from the rubber elastic body 13, and a stable vibration damping effect by the dynamic damper 10 is obtained. Further, since the radial dimension of the dynamic damper 10 is not unnecessarily increased, the dynamic damper 10 can be inserted into a small-diameter pipe.

  Furthermore, in Example 1, the axial length of the locking projection 14 of the rubber elastic body 13 is set between the pair of locking projections 14 as other parts of the rubber elastic body 13 and between the locking projection 14 and the rubber. The length in the axial direction between both ends of the elastic body 13 is made sufficiently short. Similarly, the length in the axial direction of the engagement recess 18 of the mass fitting 17 is set between the pair of engagement recesses 18 and between the engagement recess 18 and the mass fitting. By making it shorter than the axial length between both ends of 17, the axial spring characteristics of the locking projection 14 of the rubber elastic body 13 are softened. Therefore, the resonance frequency of the rubber elastic body 13 is lowered by surely shearing and deforming the locking projection 14 in addition to the compression deformation. As a result, the dynamic damper 10 can attenuate the low-frequency vibration in the radial direction.

  Further, as a first modification of the first embodiment, as shown in FIG. 4, the locking convex portion 19 of the rubber elastic body 13 has an arcuate cross section. As a result, the engagement concave portion 18 of the mass metal member 17 is brought into a pressure contact state at any position of the locking convex portion 19. Therefore, stable shearing deformation occurs in the locking projection 19 and the resonance frequency of the rubber elastic body 13 is reliably lowered. As a result, the dynamic damper 10 can stably attenuate the low-frequency vibration in the radial direction.

Next, Modification 2 will be described.
In the cylindrical dynamic damper 20 of Modification 2, as shown in FIGS. 5 and 6, the rubber elastic body 23 bonded to the inner wall surface of the outer cylinder fitting 21 has axial lengths on both sides in the middle of the axial direction. One locking projection 24 longer than the portion is provided, and correspondingly, the mass fitting 27 is also provided with one engagement recess 28 that locks the locking projection 24 at an axially intermediate position. It is. The locking projection 24 is an axial cross section composed of an inner side surface 24a having a long axial length parallel to the axial direction and a pair of inclined surfaces 24b inclined at approximately 45 ° to the center side of the inner side surface 24a on both sides in the axial direction. The shape is a substantially isosceles trapezoidal shape, and the surfaces in contact with the engaging recesses 28 at the boundary between the inner side surface 24a and the two inclined surfaces 24b are respectively arcuate curved surfaces 25. The mass fitting 27 is in pressure contact with the curved surface 25 of the locking projection 24 over the entire circumference in the radial direction on both radial surfaces 28b. Further, a gap is provided between the inner peripheral surface 23a of the rubber elastic body 23 and the outer peripheral surface 27a of the mass fitting 27, and between the engaging convex portion 24 and the engaging concave portion 28, except for the contact portion between them. ing. In addition, the length of the overlapping portion in the radial direction between the locking convex portion 24 and the engaging concave portion 28 in the locked state is about 2 mm.

  In the second modification, the axial length of the locking projection 24 is sufficiently longer than that in the first embodiment. Therefore, the shearing deformation of the locking projection 24 is less than the compression deformation. The resonance frequency is relatively higher than that of the first embodiment, and the vibration frequency to be damped is also increased. In addition, since the axial direction length of the latching convex part 24 of the rubber elastic body 23 is sufficiently long, the mass metal part 27 is sufficiently provided only by providing the mass metal part 27 with one engagement concave part 28 to be latched thereto. It can be supported coaxially. Therefore, the structure of the rubber elastic body 23 and the mass metal fitting 27 is simplified.

  Next, Example 2 will be described. As shown in FIG. 7, the dynamic damper 30 according to the second embodiment includes an inner cylindrical metal member 31 instead of the engaging convex portion 24 of the rubber elastic body 23 and the engaging concave portion 28 of the mass metal member 27. One engaging recess 34 that is recessed radially outward is provided in the middle in the axial direction of the rubber elastic body 33 that is bonded to the wall surface, and one engagement that protrudes radially outward from the mass fitting 37 corresponding to this is provided. A convex portion 38 is provided. The locking recess 34 has an axial cross-sectional shape composed of an inner side surface 34a having a long axial length parallel to the axial direction and a pair of inclined surfaces 34b inclined at approximately 45 ° toward the central side of the inner side surface 34a on both sides in the axial direction. Has a substantially isosceles trapezoidal shape. The surfaces that come into contact with the engaging convex portions 38 of the mass metal fitting 37 on the radially inner side of the both inclined surfaces 34 b of the locking concave portion 34 are respectively arcuate curved surfaces 25. The axial length of the locking recess 34 of the rubber elastic body 33 is longer than the axial length between both ends of the locking recess 34 and the rubber elastic body 33, and similarly the axial direction of the engagement protrusion 38 of the mass fitting 37. The length is longer than the axial length between both ends of the engaging convex portion 38 and the mass fitting 37.

  The mass fitting 37 is inserted into the shaft hole of the rubber elastic body 33, so that the arcuate curved surface 35 of the inclined surface 34 b of the locking recess 34 is formed on the radially outer end side of both inclined surfaces 38 b of the engaging convex portion 38. And is supported by the rubber elastic body 33 by being locked by the locking recess 34. The length of the overlapping portion in the radial direction between the locking concave portion 34 and the engaging convex portion 38 is about 2 mm. Further, the inner peripheral surface 33a (including the inner side surface 34a and the inclined surface 34b) of the rubber elastic body 33 facing each other other than the press contact portion where the inclined surface 34b of the locking recess 34 and the inclined surface 38b of the engaging convex portion 38 are in pressure contact with each other. ) And the outer peripheral surface 37a (including the bottom surface 38a and the inclined surface 38b) of the mass metal fitting 37.

  In the second embodiment having the above-described configuration, the rubber elastic body 33 is subjected to a compressive deformation and shear deformation of a portion between the locking convex portion 34 and both axial ends with respect to radial vibration. The resonance frequency is lowered to the same level as in the second modification. As a result, the dynamic damper 30 can attenuate the low-frequency vibration in the radial direction.

  In each of the above embodiments and modifications, the engaging recesses or projections of the rubber elastic bodies that engage with each other and the engagement recesses or projections of the mass metal fitting are annularly formed over the entire circumference. These may be provided in a part in the circumferential direction. Moreover, in each said Example and modification, although the engagement recessed part thru | or convex part of a rubber elastic body and the engagement recessed part thru | or convex part of a mass metal fitting are provided in one place or two places of an axial direction, 3 It can also be provided in more places. Further, in each of the above-described embodiments and modifications, the axially opposite sides of the engaging recess or protrusion of the rubber elastic body are inclined surfaces, but a vertical surface extending in the radial direction with respect to the inner peripheral surface and You can also Further, in each of the above embodiments and modifications, the cylindrical dynamic damper is used to attenuate the radial vibration in the pipe in the seat. It can also be inserted and used. In addition, the cylindrical dynamic damper shown in each of the above embodiments and modifications is an example, and can be implemented in various forms without departing from the gist of the present invention.

  According to the present invention, the mass metal fitting is linearly in contact with the inclined surface of the rubber elastic body on the inclined surface, and a gap is formed between the inner peripheral surface of the rubber elastic body and the outer peripheral surface of the mass metal fitting facing each other. By being provided, the rubber elastic body can be subjected to shear deformation as well as compression against vibration in the radial direction of the mass metal fitting, and its spring characteristics are softened. As a result, the resonance frequency of the dynamic damper is set to a low frequency, and the low frequency vibration in the radial direction of the mating member can be suppressed, so that the present invention is useful.

It is sectional drawing of the II line direction of FIG. 2 which shows the cylindrical dynamic damper which is Example 1 of this invention. It is sectional drawing of the II-II line direction of FIG. 1 which shows the same cylinder type dynamic damper. It is an expanded sectional view which shows the principal part of a cylindrical dynamic damper. It is an expanded sectional view showing the important section of the cylinder type dynamic damper which is modification 1. It is sectional drawing of the VV line direction of FIG. 6 which shows the cylindrical dynamic damper which is the modification 2. FIG. It is sectional drawing of the VI-VI line direction of FIG. 5 which shows the same cylinder type dynamic damper. It is sectional drawing in the axial line position which shows the cylindrical dynamic damper which is Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Cylindrical dynamic damper, 11 ... Outer cylinder metal fitting, 13 ... Rubber elastic body, 14 ... Locking convex part, 14a ... Inner side surface, 14b ... Inclined surface, 15 ... Curved surface, 17 ... Mass metal fitting, 18 ... Engagement recessed part , 18a ... bottom surface, 18b ... inclined surface, 20 ... cylindrical dynamic damper, 21 ... outer cylinder fitting, 23 ... rubber elastic body, 24 ... locking projection, 24a ... inner side surface, 24b ... inclined surface, 25 ... curved surface, 27 ... Mass fitting, 28 ... Engagement recess, 28a ... Bottom, 28b ... Inclined surface, 30 ... Cylindrical dynamic damper, 31 ... Outer cylinder fitting, 33 ... Rubber elastic body, 34 ... Locking projection, 34a ... Inner side 34b ... inclined surface, 35 ... curved surface, 37 ... mass fitting, 38 ... engaging recess, 38a ... bottom surface, 38b ... inclined surface.

Claims (6)

A cylindrical metal fitting attached to the mating member;
Locking that is a convex portion that is bonded to the inner wall surface of the cylindrical metal fitting and that protrudes radially inward from at least a part of the inner peripheral surface or a concave portion that is recessed radially outward at at least one point in the axial direction. A cylindrical rubber elastic body provided with a portion;
It is a rod-shaped metal fitting inserted through the shaft hole of the rubber elastic body, and is a recess recessed radially inward or a protrusion protruding radially outward at a position corresponding to the locking portion on the outer peripheral surface thereof. An engaging portion having an inclined surface inclined at a predetermined angle toward opposite directions at both ends in the axial direction and an inner surface sandwiched between the inclined surfaces. A mass fitting that is locked to the stopper and supported by the rubber elastic body,
The inclined surface of the mass metal fitting is in radial contact with both axial sides of the rubber elastic body, and the inner circumferential surface of the rubber elastic body and the outer circumferential surface of the mass metal fitting which are opposed to each other other than the pressure contact portion A cylindrical dynamic damper characterized in that a gap is provided between them. The locking portion of the rubber elastic body has a pair of inclined surfaces inclined at a predetermined angle toward opposite directions at both ends in the axial direction, and an inner surface sandwiched between the inclined surfaces. Item 2. The cylindrical dynamic damper according to Item 1. 3. The cylindrical dynamic damper according to claim 1, wherein an axial cross-sectional shape of at least a portion of the engaging portion of the rubber elastic body that contacts the engaging portion of the mass metal fitting is an arc shape. The cylinder according to any one of claims 1 to 3, wherein the engaging portion of the rubber elastic body and the engaging portion of the mass metal fitting have an annular shape along the entire circumference in the circumferential direction. Type dynamic damper. The cylinder according to any one of claims 1 to 4, wherein the dimension of the overlapping portion in the radial direction of the engaging portion of the rubber elastic body and the engaging portion of the mass metal fitting is 1 to 3 mm. Type dynamic damper. When the engaging part of the rubber elastic body is a convex part, the axial length of the engaging part is made shorter than the axial length of the other part of the rubber elastic body, and the engaging part of the mass metal fitting When the axial length is shorter than the axial length of the other part of the mass metal fitting, and the engaging part of the rubber elastic body is a recess, the axial length of the engaging part is set to the other part of the rubber elastic body. The length in the axial direction of the portion of the metal fitting and the length in the axial direction of the engaging portion of the metal fitting are made longer than the length in the axial direction of the other portion of the metal fitting. The cylindrical dynamic damper according to any one of claims.

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