JP2001248683A - Dynamic damper device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dynamic damper device of a novel structure that can facilitate an external visual confirmation of dynamic damper mounting in a normal position on a rodlike vibrator. SOLUTION: A dynamic damper 12 comprises a cylindrical mass part 22 and elastic support parts 24 disposed at both axial ends of the mass part 22. For mounting of the dynamic damper 12 on a rodlike vibrator 10, that place of the rodlike vibrator 10 which carries the dynamic damper 12 in place has a small-diameter portion 14. Step faces 18 at both axial ends of the small- diameter portion 14 position the axially outward end faces of the elastic support parts 24 of the dynamic damper 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow or solid rod-shaped vibrator to which vibration is transmitted and vibrated, such as various shafts, arms, pipes, etc. The present invention relates to a dynamic damper device having a damper.

[0002]

2. Description of the Related Art Such a dynamic damper device includes, for example, a shaft or an arm as a force transmitting member,
It is known as one of effective measures against vibration problems such as resonance and vibration transmission of various rod-shaped structural members such as a tube forming a fluid flow path. As a specific structure of such a dynamic damper device, for example, Japanese Unexamined Patent Publication No. Hei.
As described in Japanese Patent No. 37915, etc., a dynamic damper having elastic support portions on both sides in the axial direction of a mass portion having a substantially cylindrical shape is externally disposed on a rod-shaped vibrator, and the mass portion is provided. Are positioned at a predetermined distance radially outward of the rod-shaped vibrating body, and a structure in which the rod-shaped vibrating body is elastically supported via the elastic supporting portion has been proposed. For example, a dynamic damper for a drive shaft of an automobile because the displacement characteristics are stable, and it is possible to obtain an effective vibration effect not only in the bending direction but also in the torsional direction. Application to devices and the like is under consideration.

In such a dynamic damper device, it is necessary to consider the relationship between the vibration mode of the rod-shaped vibrator and the mounting position of the dynamic damper in order to stably obtain an effective vibration damping effect. It is important to position and attach the dynamic damper at a position where the vibration mode of the vibrating body is antinode, and to prevent displacement.

However, in the conventional dynamic damper device, as described in the above-mentioned publication, the axial displacement of the dynamic damper in the axial direction is prevented by a tightening belt for tightening the elastic support portion of the dynamic damper from the outer peripheral surface. Therefore, the positioning of the dynamic damper device at the time of mounting is difficult and unstable. Japanese Patent Application Laid-Open No. 8-28627 discloses a structure in which a positioning inclined surface or a step is provided between an inner peripheral surface of an elastic support portion and an outer peripheral surface of a rod-shaped vibrating body in a dynamic damper so that positioning can be performed. However, in such a structure, when the dynamic damper is mounted, the alignment portion is covered by the elastic support portion of the dynamic damper and cannot be seen from the outside, and the alignment state at the time of mounting is not changed. Since it cannot be confirmed visually, there is a case where even if a position shift occurs, it may not be noticed, and the positioning workability and the positioning accuracy of the dynamic damper are not yet sufficient.

[0005]

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a dynamic damper attached to a rod-shaped vibrating body at a regular position from the outside. It is an object of the present invention to provide a dynamic damper device having a novel structure, which can be easily visually checked and a dynamic damper can be easily mounted at a target position.

[0006]

An embodiment of the present invention which has been made to solve such a problem will be described below. In addition, each of the components employed in each of the embodiments described below can be employed in any combination as much as possible. Further, the configuration and technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or based on an inventive concept that can be understood by those skilled in the art from the descriptions. It should be understood that the

That is, the features of the present invention are as follows:
A dynamic damper having elastic support portions on both sides in the axial direction of a mass portion having a substantially cylindrical shape is externally arranged on a rod-shaped vibrating body, and the mass portion is radially outwardly mounted on the rod-shaped vibrating body. In a dynamic damper device which is positioned at a predetermined distance from and is elastically supported by the rod-shaped vibrating body via the elastic supporting portion,
A small diameter portion is formed at the mounting portion of the dynamic damper in the rod-shaped vibrating body, and the elastic support portions on both sides in the axial direction are externally attached to the small diameter portion and assembled.
An axial outer end surface of each elastic support portion is positioned by a step surface at an axial outer end portion of the small diameter portion.

In such a dynamic damper device having the structure according to the present invention, the whole of the dynamic damper is extrapolated and mounted on the rod-shaped vibrating body, and the axially outer end faces of the respective elastic support portions of the dynamic damper are formed. According to the positional relationship between the small-diameter portion of the rod-shaped vibrator and the step surface at the axially outer end, it is possible to easily confirm the suitability of the dynamic damper with respect to the normal mounting position in the axial direction with respect to the rod-shaped vibrator. . That is, in the regular mounting position, the axially outer end faces of the respective elastic support portions of the dynamic damper are all positioned so as to abut on the stepped surface of the rod-shaped vibrating body or to approach axially inward. Therefore, a slight displacement on any side in the axial direction of the dynamic damper can be easily visually confirmed from the outside by displacing the position of the axially outer end face of each elastic support portion with respect to both step surfaces. . Therefore,
The dynamic damper can be easily and reliably mounted on the rod-shaped vibrating body at a regular position, and after the dynamic damper is mounted, the axial end surfaces of the both-side elastic support portions of the dynamic damper are rod-shaped vibrating bodies. Abuts or is locked against the step surface of the small-diameter portion, thereby effectively preventing the axial displacement of the dynamic damper on the rod-shaped vibrating body. In this case, the displacement of the dynamic damper can be easily visually recognized from the outside, and can be quickly corrected, so that the intended vibration damping effect of the dynamic damper device can be stably obtained. It is.

Further, a dynamic damper is provided between the step surfaces of the rod-shaped vibrating body, and the extension of each elastic support portion outward in the axial direction is restricted by the step surfaces on both sides. Even when the spring characteristics of the elastic support portion change and become soft due to the temporal change due to the use of the dynamic damper, the restraining force for restricting the elastic support portion from extending outward in the axial direction is controlled by the elastic support portion. It acts in a direction to assist the support spring elasticity of the mass member, and the desired damping effect by the dynamic damper can be stably obtained over a long period of time.

The positioning of the axially outer end of the elastic support portion by the step surface of the axially outer end portion of the small diameter portion necessarily causes the axially outer end surface of the elastic support portion to abut the step surface. It is not necessary, and a slight gap may exist between them. Even in such a configuration, the effects of the present invention as described above can be effectively exhibited.

In the present invention, for example, it is advantageous that the small-diameter portion of the rod-shaped vibrator is formed continuously with a substantially constant diameter over the entire axial length of the dynamic damper. Can be adopted.

Alternatively, in the present invention, for example,
The two small-diameter portions of the rod-shaped vibrating body, in which the elastic support portions on both sides in the axial direction of the dynamic damper are respectively extrapolated and assembled, are formed separately and separately from each other in the axial direction, and A configuration in which the end face on the inner side in the axial direction of the elastic support member is tapered toward the inner side in the axial direction and is overlapped with the rising face on the inner side in the axial direction of the elastic support member can also be suitably adopted.

In the present invention, a tightening band which exerts a tightening and fixing force on a small diameter portion of the rod-shaped vibrator is externally attached to at least one elastic support portion of the dynamic damper. A configuration may be advantageously employed. Thus, the dynamic damper can be more firmly fixed to the small-diameter portion of the rod-shaped vibrator, so that the axial displacement of the dynamic damper after mounting can be more effectively prevented. .

Further, in the present invention, the shape of the step surface on the axially outer side of the small diameter portion of the rod-shaped vibrating body is not limited at all. A configuration having a tapered surface inclined outward in the axial direction can be suitably adopted. This allows
As compared with the case where such a step surface is substantially at a right angle, the operation of externally inserting the dynamic damper into the small diameter portion of the rod-shaped vibrator becomes easier, and the workability of assembling the dynamic damper device is further improved. obtain.

Here, the axially outer end face of each elastic support portion of the dynamic damper can be appropriately changed according to the shape of the step surface as described above. It is desirable that the direction end surface and each of the opposing step surfaces have a corresponding shape and are brought into contact with a sufficient area.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, a specific example in which the present invention is applied to a vibration damping device for a drive axle (drive shaft) of an automobile will be described.

FIG. 1 shows a drive shaft 10 as a rod-shaped vibrator on which a dynamic damper 12 is mounted, as one embodiment of the present invention. The drive shaft 10 has a long rod shape having a hollow or solid substantially circular outer peripheral surface as a whole, and one end in the axial direction is connected to an output shaft of a final reduction gear device via a universal joint. The other end is connected to the drive shaft.

A dynamic damper 12 is mounted on a central portion of the drive shaft 10 in the axial direction. Here, the mounting portion of the dynamic damper 12 on the drive shaft 10 has a predetermined axial length:
A small diameter portion 14 of a circular outer peripheral surface formed continuously over the length L1 with a substantially constant outer diameter dimension: D1. On both sides in the axial direction of the small-diameter portion 14, large-diameter portions 16, 16 of a circular outer peripheral surface extending continuously outward in the axial direction with a substantially constant outer diameter dimension: D2 are formed. Large diameter part 16,
Step surfaces 18, 18 are formed at a boundary portion of 16.
In the present embodiment, each step surface 18 is a tapered surface 20 that is inclined outward in the axial direction. In addition, the small diameter portion 14 in the present embodiment is formed directly on the drive shaft 10 by cutting, drawing, forging, or the like, and its outer diameter dimension D1 is substantially constant over the entire length in the axial direction. Cylindrical outer peripheral surface.

On the other hand, the dynamic damper 12 mounted on the drive shaft 10 has a substantially cylindrical shape as a whole as shown in FIG. At the same time, both sides in the axial direction of the mass portion 22 are elastic support portions 24, 24.

Here, the mass portion 22 is a cylindrical mass body 26 made of a material having a relatively large mass such as a metal such as iron and steel, and the inner and outer peripheral surfaces thereof are covered with a covering rubber layer 28. It has a structure. On the other hand, the elastic support portions 24, 24 are formed of a rubber material such as natural rubber, and have tapered cylindrical tapered portions 30, 30 whose diameter gradually decreases as going outward in the axial direction. The cylindrical extension cylindrical portions 32, 32 extending outwardly in the axial direction with substantially constant inner and outer diameters from the axially outer end portions of the cylindrical members 30, 30 are integrally formed. The tapered portions 30, 30 and the extended cylindrical portions 32, 32
Are formed integrally with the covering rubber layer 28 of the mass portion 22. The axial end surface of each extension cylindrical portion 32 is formed such that the inner peripheral side corner portion 34 has a shape corresponding to the shape of the step surface 18 of the drive shaft. That is, in the present embodiment, the inner corner 34 in the radial direction is the tapered surface 2.
It has a chamfered tapered shape corresponding to 0.

Further, in the dynamic damper 12 of the present embodiment, the axial length thereof is substantially the same as the axial length L1 of the small diameter portion 14 formed on the drive shaft 10, and the dynamic The entire damper 12 is located in the small-diameter portion 14, in other words, between the step surfaces 18, 18.
It is extrapolated. Also, each elastic support portion 24
, The inner diameter of the tapered portion 30 is larger than the outer diameter of the small diameter portion 14: D1, while the inner diameter of the extension cylindrical portion 32 is set slightly smaller than the outer diameter of the small diameter portion 14: D1. .

The dynamic damper 1 as described above
2 is extrapolated from one side in the axial direction with respect to the drive shaft 10, and as shown in FIG.
2 is positioned radially outward of the small diameter portion 14 at a predetermined distance, and the tapered portions 30, 30 of the elastic support portions 24, 24 are spaced apart radially outward of the small diameter portion 14. The extended cylindrical portions 32 are attached to the small-diameter portion 14 by closely fitting the outer peripheral surfaces at both axially outer end portions thereof. Thereby, the mass portion 22 is elastically supported by the drive shaft 10 via the elastic support portions 24, 24.

The dynamic damper 12 attached to the drive shaft 10 in this manner constitutes a sub-vibration system using the mass portion 22 as a mass and the elastic support portions 24, 24 as springs. As with the damper, a damper effect against torsional vibration and bending vibration in the drive shaft 10 as main vibration can be exerted.

In the dynamic damper device having the structure according to the present embodiment, the small diameter portion 14 of the drive shaft 10 is formed with a predetermined length: L1 in the axial direction, and the shaft of the dynamic damper 12 is formed. The length in the direction is substantially the same as or slightly smaller than the length in the axial direction of the small diameter portion 14, and when the dynamic damper 12 is externally mounted on the drive shaft 10, the entire length of the dynamic damper 12 fits into the small diameter portion 14. The inner peripheral corners 34, 34 of the extension cylinder portions 32, 32 on both sides are
8, 18 are in contact. Thus, in the drive shaft 10, the step surfaces 18, 18 that define the both axial ends of the mounting position of the dynamic damper 12 are located at both the axial ends of the dynamic damper 12, and these step surfaces 18, 18 are provided. And dynamic damper 12
Since the alignment state of both axial ends of the dynamic damper 12 can be easily visually confirmed from the outside, the alignment work of the dynamic damper 12 is easier than that of the dynamic damper device of the conventional structure, and after the mounting. In this case, the positional displacement of the dynamic damper 12 after the mounting can be easily visually confirmed from the outside only by checking the distance between the stepped surface 18 and the axially outer end of each of the elastic support portions 24 facing each other. You can check it. Therefore, in the dynamic damper 12 having the above-described structure, the dynamic damper 12 can be easily mounted on the drive shaft 10 with accurate positioning accuracy as compared with the dynamic damper device having the conventional structure. The positional displacement in the direction can be easily found and corrected quickly, and the intended vibration-damping effect can be effectively obtained by being correctly mounted at the correct position.

Further, in the dynamic damper device of the present embodiment, the elastic support portions 24, 24 are fitted and fixed to the small diameter portion of the drive shaft 10 by the elastic force in the radial direction. Since the inner peripheral corners 34, 34 of the axially outer end surfaces of the portions 24, 24 abut against and are respectively engaged with the step surfaces 18, 18, of the drive shaft 10, the dynamic in the axial direction of the drive shaft. The displacement of the damper 12 is advantageously prevented, and the damper 12 can be stably held at the target position.

In this embodiment, the step surface 18 is used.
Is formed as a tapered surface 20 that is inclined outward in the axial direction, so that the elastic support portions 24 and 2 for the small-diameter portion 14 are formed.
4 and the mounting of the dynamic damper 12 to the drive shaft 10 can be performed more easily.

Furthermore, the movement of each elastic support portion 24 of the dynamic damper 12 to the outside in the axial direction is restricted by each step surface 18 provided on the drive shaft 10. Even when the spring characteristics are softened due to settling or the like in the support portion 24,
The axially inward restraining force exerted on each elastic support portion 24 by the step surface 18 acts in a direction that assists the elasticity of the elastic support portion 24, and thus the spring characteristic of each elastic support portion 24 is improved. A significant reduction is prevented, the intended vibration damping effect can be effectively exhibited, and the durability of the dynamic damper 12 can be improved.

Further, in the dynamic damper device having the structure according to the present embodiment, since the small-diameter portion 14 is formed continuously with a substantially constant outer diameter dimension: D1, the shape of the small-diameter portion 14 varies. Therefore, there is also an advantage that the variation in the vibration absorbing characteristics of the dynamic damper 12 due to the above is avoided, and the intended vibration damping characteristics can be stably exhibited.

Next, FIG. 2 shows a second embodiment of the dynamic damper device according to the present invention. In addition,
In the present embodiment, members and parts having the same structure as the first embodiment are denoted by the same reference numerals as those in the first embodiment in the drawings, respectively, so that detailed descriptions thereof are given. Omitted.

That is, in the dynamic damper device of the present embodiment, one of the elastic support portions 24 of the dynamic damper 12 (in this embodiment, the right side in FIG. 2)
Extending continuously in the circumferential direction on the outer peripheral surface of the extension tubular portion 32;
A groove 38 for attaching a band is provided. The dynamic damper 12 is externally inserted into the drive shaft 10 and is mounted so as to be positioned on the small-diameter portion 14. The dynamic damper 12 is fastened to the groove 38 provided in the one extension cylindrical portion 32. With the attached band 40, the extension tubular portion 32
Are firmly fixed to the outer peripheral surface of the small diameter portion 14.

By employing such a tightening band 40,
The dynamic damper 12 is more firmly fixed to the drive shaft 10, so that the displacement of the dynamic damper 12 after mounting is advantageously avoided, and the dynamic damper 12 can exhibit more stable vibration absorbing characteristics. . In this embodiment, the fastening band 4
0 is the elastic support 2 on one side of the dynamic damper 12
4 is attached only to the extension tubular portion 32,
It may be provided on the extension cylinder portions 32 on both sides.

Next, FIG. 3 shows a third embodiment of the dynamic damper device according to the present invention. In addition,
In the present embodiment, members and parts having the same structure as the first embodiment are denoted by the same reference numerals as those in the first embodiment in the drawings, respectively, so that detailed descriptions thereof are given. Omitted.

That is, in the drive shaft 10 of the present embodiment, the small-diameter portions 44, 44 having a pair of circular outer peripheral surfaces formed at a predetermined distance in the axial direction have substantially constant outer diameter dimensions: D3. And a predetermined length in the axial direction: L2, L
2 and the small diameter portions 4
The large-diameter portion 46 having a circular outer circumferential surface between the small-diameter portion 44 and the small-diameter portion 44 has an outer diameter dimension D larger than D3.
4, that is, it is formed continuously with a predetermined axial length: L3 having an outer diameter substantially the same as the outer diameter of the drive shaft. Further, each of the small diameter portions 44 in the present embodiment has a tapered support surface 48 whose inner axial end surface is inclined inward in the axial direction, while its outer axial end surface has a substantially right-angled step surface. 50. In this embodiment also, the small diameter portions 44, 44 can be formed integrally with the drive shaft 10 by drawing, forging, cutting, or the like, and the outer diameter: D3 of which is substantially constant in the axial direction. It is formed with an outer peripheral surface.

On the other hand, the dynamic damper 12 mounted on the drive shaft 10 of the present embodiment having such a structure has the entire length of the small diameter portions 44, 44 and the large diameter portion 46 provided on the drive shaft 10. The total axial length is set to be substantially the same as or slightly smaller than L2 + L2 + L3, and the axial length of each extension cylindrical portion 32 is substantially the same as each small-diameter portion 44 of the drive shaft 10. Alternatively, the length is set to be slightly smaller in the axial direction. Further, the inner peripheral corners on the inner side in the axial direction of the extension cylindrical portions 32, 32, that is, the rising surfaces on the inner side in the axial direction of the elastic support portions 24, 24 are formed on the small diameter portion 4 of the drive shaft 10.
4 and 44 are formed so as to have a shape corresponding to the tapered support surfaces 48 and 48 provided on the tapered support surfaces 48 and 48, that is, a tapered surface 52 having an inner diameter gradually increasing toward the inner side in the axial direction. The peripheral corner is formed so as to have a shape corresponding to the step surface, that is, a substantially right angle.

The dynamic damper 1 as described above
2 is attached to the drive shaft 10 by being extrapolated from one side in the axial direction, similarly to the above-described embodiment, but as shown in FIG.
2 are located on the large-diameter portion 46 of the drive shaft 10, and the extended cylindrical portions 32, 32 are fitted into the small-diameter portions 44, 44 of the drive shaft 10, respectively.
It is attached by being fixed on the outer peripheral surface of 44. Also in the present embodiment, since the inner diameter of each extension cylindrical portion 32 in the free state is slightly smaller than the outer diameter of each small diameter portion: D3, the elastic force of the extension cylindrical portion 32 is reduced. Thereby, the dynamic damper 12 is closely fixed to the outer peripheral surface of the drive shaft 10.

In the dynamic damper device of the present embodiment, similarly to the above-described embodiment, the extension cylindrical portion 32,
The radially outer end of the dynamic damper 32 is abutted and engaged with the step surfaces 50, 50 provided on the axially outer end of the small diameter portions 44, 44, so that the dynamic damper is radially outward. In addition to being able to prevent misalignment, the tapered surfaces 52, 52 provided at the radially inner ends of the extension tubular portions 32, 32 further have the drive shaft 1
The tapered support surfaces 48, 48 provided at the axially inner ends of the small-diameter portions 44 at 0 are respectively engaged and locked, so that the axial displacement of the dynamic damper 12 can be prevented. It has become.

In the dynamic damper 12 of the present embodiment having such a structure, the drive shaft 1
By forming two small-diameter portions 44 provided at zero in the axial direction, tapered support surfaces 48 can be advantageously provided, and the tapered support surfaces 48 can be advantageously provided.
By bringing the tapered surfaces 52, 52 of the extension tubular portions 32, 32 into close contact with each other, the dynamic damper 1
The positioning in the axial direction and the prevention of the displacement in the axial direction in the mounting state 2 can be more advantageously and stably performed. Also in the present embodiment, the dynamic damper 12 is visually checked at the time of mounting and after mounting, depending on the positional relationship between the axially opposite end surfaces of the dynamic damper 12 and the step surfaces 50, 50 located adjacent to the axially outward side. It is possible to easily confirm the positional deviation of the first embodiment, and thereby, the same effect as in the first embodiment can be exerted.

Further, in the dynamic damper device of the present embodiment, the axial separation distance M1 between the pair of tapered support surfaces 48 provided on the drive shaft 10 is M1.
Is changed from the axial length M2 of the mass portion 22, that is, the elastic support portion 2 of the dynamic damper 12 which extends and is positioned between the tapered support surfaces 48, 48.
By adjusting the axial length M3 of 4, 24, the spring constant of the dynamic damper 12 can be tuned appropriately.

Next, FIG. 4 shows a fourth embodiment as a dynamic damper device of the present invention. The drive shaft 10 in the fourth embodiment is formed continuously with a substantially constant outer diameter dimension: D5 over its entire length, and a dynamic damper 12 is attached to a substantially central portion thereof. On the other hand, the dynamic damper 12 according to the first embodiment is the same as the dynamic damper 12 of the first embodiment except that the inner peripheral corners 34, 34 of the axially outer end faces of the extension tubular parts 32, 32 are substantially perpendicular. The configuration is the same as described above. In the free state, the inner diameter of the extension cylindrical portions 32, 32 of the dynamic damper 12 is slightly smaller than the outer diameter D5 of the drive shaft 10.

After the dynamic damper 12 having the above-described configuration is externally mounted on the drive shaft 10 and externally mounted at a predetermined mounting position, the dynamic damper 12 is formed of a metal or other constituent member from both axial sides of the drive shaft 10. The stepped surfaces 18, 18 of the present invention are formed by press-fitting and fixing the projected ridge rings 54, 54.

In the dynamic damper device of the present embodiment having such a structure, the drive shaft 10
Since the outer diameter of the dynamic damper 12 is substantially the same over its entire length, the extrapolation and mounting of the dynamic damper 12 can be performed more easily, and the step surfaces 18, 18 formed by the ridge rings 54, 54. Accordingly, the work of easily positioning the dynamic damper 12 in the axial direction and the prevention of the axial displacement can be both effectively achieved.

Further, in the dynamic damper device of this embodiment, the ridge rings 54, 54 made of separate members are used.
Thus, since the step surfaces 18 are formed, the degree of freedom in setting the radial dimension of each ridge ring 54 as the step surface is greatly increased. Accordingly, it is possible to provide the ridge rings 54, 54 having sufficient radial dimensions, whereby the displacement of the dynamic damper 12 to the radial outside can be more advantageously achieved.

In addition, by employing the ridge rings 54, 54, the step surface 18 can be provided, so that it is not necessary to form a small-diameter portion on the drive shaft 10, and thus, the small-diameter portion can be provided. Concentration of stress on the drive shaft 10 due to the formation of the portion is avoided, and the durability of the dynamic damper device can be improved.

The method of fixing each of the ridge rings 54 is not particularly limited, and may be fixed by welding or the like in addition to press-fitting.

Although the first to fourth embodiments of the present invention have been described in detail above, these are merely examples,
The present invention is not construed as being limited by the specific description in these embodiments.

For example, as the drive shaft used in the dynamic damper device of the present invention, any drive shaft can be used as long as it has step surfaces at both ends of a mounting portion of the dynamic damper device. There is no particular limitation as long as the axial outer end face of the dynamic damper can be positioned with a contact or a small gap.

Further, the present invention comprises two cylindrical mass parts which are arranged at a predetermined distance in the axial direction and are spaced apart from each other by a predetermined distance.
The present invention is also applicable to a so-called double mass type dynamic damper having a structure in which one of elastic support portions provided on both axial sides of each mass portion is integrally connected to each other. In this case, at least one of the elastic support portions formed on the outside in the axial direction with respect to each of the mass portions is externally mounted on the small-diameter portion of the rod-shaped vibrator, and the stepped surface of the small-diameter portion is provided. It is sufficient that the axial end portion is positioned, and the resilient support portions connected to each other need not necessarily be positioned in the axial direction.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, various changes, modifications, improvements and the like can be performed in embodiments, and unless such embodiments depart from the spirit of the present invention.
Both are included in the scope of the present invention,
Needless to say.

[0049]

As is apparent from the above description, in the dynamic damper device having the structure according to the present invention, the state of mounting the dynamic damper on the rod-shaped vibrator at the proper position can be easily visually confirmed from the outside. Therefore, it is possible to easily and stably mount the dynamic damper at a target position.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view showing a dynamic damper device as a first embodiment of the present invention.

FIG. 2 is an explanatory longitudinal sectional view showing a dynamic damper device as a second embodiment of the present invention.

FIG. 3 is an explanatory longitudinal sectional view showing a dynamic damper device as a third embodiment of the present invention.

FIG. 4 is an explanatory longitudinal sectional view showing a dynamic damper device as a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Drive shaft 12 Dynamic damper 14 Small diameter part 18 Step surface 20 Mass part 24 Elastic support part 32 Extension cylinder part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Michio Kasahara 3-1, Higashi 3-chome, Komaki City, Aichi Prefecture F-term (reference) 3J048 AA06 AD07 AD10 BF02 DA06 EA29 EA31 3J066 AA01 AA26 AA29 DA07 DB03

Claims (5)

[Claims] 1. A dynamic damper having elastic support portions on both sides in the axial direction of a mass portion having a substantially cylindrical shape is extrapolated and disposed on a rod-shaped vibrator, and the mass portion is moved by the rod-shaped vibration member. A dynamic damper device which is positioned radially outward of the body at a predetermined distance and is elastically supported by the rod-shaped vibrating body via the elastic supporting portion; A small diameter portion is formed in the mounting portion, and the elastic support portions on both sides in the axial direction are extrapolated to the small diameter portion and assembled,
A dynamic damper device, wherein the axially outer end surfaces of the respective elastic support portions are respectively positioned by step surfaces of the axially outer end portions of the small diameter portion. 2. The dynamic damper device according to claim 1, wherein the small-diameter portion of the rod-shaped vibrator is formed continuously with a substantially constant outer diameter over the entire axial length of the dynamic damper. 3. The small-diameter portion of the rod-shaped vibrating body to which the elastic support portions on both sides in the axial direction of the dynamic damper are respectively extrapolated and assembled is formed independently and separately from each other in the axial direction. 2. The dynamic damper device according to claim 1, wherein the axially inner end surfaces of the small diameter portions are tapered support surfaces inclined inward in the axial direction and are superposed on the axially inner rising surfaces of the elastic support portions. . 4. A rod according to claim 1, wherein a clamping band exerting a clamping force on a small-diameter portion of said rod-shaped vibrator is externally attached to at least one elastic supporting portion of said dynamic damper. The dynamic damper device according to any one of the above. 5. The dynamic damper device according to claim 1, wherein the step surface at the axially outer end of the small diameter portion is a tapered surface inclined outward in the axial direction.