JPH07248045A - Dynamic damper - Google Patents

Abstract

PURPOSE:To prevent the formation of a clearance and the penetration of moisture from the outside to a dynamic damper by suppressing the vibration of bending or twisting caused in a rotating shaft. CONSTITUTION:A mass member 10 has a metal cylindrical body 11 covered with a rubber film. A rubber first elastic member 20 has a cylindrical first fixing part 21 and a substantially hollow truncated conical first connecting part 22 provided between the mass member 10 and the first fixing part 21 to integrally connect the both to each other, and it is fastened and fixed to a drive shaft S by a ring fastening member. A rubber second elastic member 30 has a cylindrical second fixing part 31 and a substantially hollow truncated conical second connecting part 32 provided between the mass member 10 and the second fixing part 31 to integrally connect the both to each other. A hollow truncated conical interrupting member 33 is integrally provided on the left end of the second cylindrical member. The interrupting member is formed to have a bore diameter on the outer end part smaller than the bore diameter of the second cylindrical member and a thickness thinner than the second cylindrical member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper which is mounted on a rotary shaft such as a drive shaft of an automobile or the like and suppresses harmful vibrations such as bending vibration and torsional vibration generated on the rotary shaft.

[0002]

2. Description of the Related Art Conventionally, as a dynamic damper of this type, as shown in, for example, Japanese Patent Laid-Open No. 62242/1990, both ends of a cylindrical mass member 1 having an inner diameter larger than the outer diameter of a rotary shaft such as a drive shaft. In addition, it is known that a cylindrical fixing portion 3 having an inner diameter smaller than the outer diameter of the rotating shaft is integrally connected via a hollow frustoconical connecting portion 2 made of an elastic material such as rubber. Further, in this dynamic damper, the fixing portion 3 is fitted to the rotating shaft and press-fitted to a predetermined position, and further, in order to prevent the displacement due to the vibration of the rotating shaft, the fixing portion 3 is made of metal or resin. The band was wound and fastened and fixed to the rotary shaft (see FIG. 7A).

As another dynamic damper,
As shown in Japanese Utility Model Laid-Open No. 3-25048, the fixing portion 4 having the same structure as the dynamic damper and having one side is provided.
The inner diameter of the fixing part 5 is smaller than that of the other fixing part 5, and the fixing part is fixed to the rotating shaft by a band.
The only one was known (see FIG. 7 (b)). This dynamic damper causes the inner peripheral surface of the fixed portion to uniformly and closely contact the rotary shaft by the strong tightening force of the fixed portion 4 on the one end side having a small inner diameter, so that the vibration between the fixed portion 4 and the rotary shaft is caused by vibration of the rotary shaft. The gap was prevented. Therefore, intrusion of moisture or the like from the outside into the gap between the mass member 1 of the dynamic damper and the rotary shaft is suppressed, and the reliability of the dynamic damper is ensured. Further, with such a configuration, the cost of parts is reduced and the workability of assembling is improved. Then, in each of the dynamic dampers described above, when the harmful vibration is generated by the rotation of the rotating shaft, the mass member 1 having a natural frequency matched with the vibration frequency is transmitted through the connecting portion 2. By resonating with, the vibration was converted into vibration energy and absorbed.

[0004]

However, in the case of the above-mentioned dynamic damper, it is often used in a harsh environment where it is usually exposed to the outside air near the surface of the earth. Occurred and the force for tightening the rotating shaft was reduced. Therefore, in the latter dynamic damper, a gap is generated between the fixed portion on the side not fastened with the band and the rotary shaft, and moisture or the like enters the gap between the mass member of the dynamic damper and the rotary shaft from the outside to There is a problem that the ability of the member to absorb harmful vibration is reduced. In order to avoid this, it is conceivable to make the inner diameter of the fixed part smaller to increase the tightening force in the radial direction, but the resistance when the fixed part is fitted into the rotary shaft and press-fitted becomes large, and There is a problem that it becomes very difficult to press-fit the damper into the rotary shaft.

Further, when tightening with a band like the fixing part on the other end side of the latter or the fixing part on both ends of the former dynamic damper, the tightening is performed in a short time using an inexpensive band. In such a case, the uniformity of the tightening force becomes insufficient, and, for example, as shown in FIG. 5, a stress in the circumferential direction is applied to a part of the fixed part, and that part is slightly lifted from the rotating shaft to form a gap. Sometimes. Then, there is a problem that moisture or the like in the external atmosphere enters from the gap into the gap between the mass member of the dynamic damper and the rotating shaft. SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and an object of the present invention is to provide a dynamic damper which has a simple structure while preventing intrusion of moisture or the like from the outside.

[0006]

In order to achieve the above-mentioned object, the structural feature of the invention according to claim 1 is that the cylindrical shape has an inner diameter larger than the diameter of the rotary shaft and is inserted into the rotary shaft. And a cylindrical first fixing part which is made of an elastic material and has an inner diameter smaller than the diameter of the rotating shaft, is fitted into the rotating shaft, is press-fitted, and is fixed by the tightening member, and the inner end of the first fixing part. And a first connecting portion integrally connecting one end of the mass member with the first connecting member, and an elastic material having an inner diameter smaller than the inner diameter of the first fixing portion and being fitted into the rotary shaft by press fitting. And a second elastic member provided with a second connecting portion that integrally connects the inner end of the second fixing portion and the other end of the mass member to each other.
A hollow truncated cone-shaped blocking member, which is thinner than the second fixing portion and protrudes outward so that the inner diameter is smaller, is provided at the outer end of the fixing portion, and the inner diameter of the tip is smaller than the inner diameter of the second fixing portion. Especially.

Further, the structural feature of the invention according to claim 2 is that in the dynamic damper according to claim 1, the outer end of the first fixing portion is made of an elastic material and is thinner than the first fixing portion. Further, there is provided a hollow truncated cone-shaped blocking member that projects outward so that the inner diameter becomes smaller and the inner diameter of the tip is smaller than the inner diameter of the first fixing portion.

Further, the structural feature of the invention according to claim 3 is that the cylindrical mass member having an inner diameter larger than the diameter of the rotating shaft and inserted through the rotating shaft, and the rotating shaft made of an elastic material. A first fixing part having an inner diameter smaller than the diameter, fitted into a rotary shaft, press-fitted, and fixed by a tightening member, and a first connection integrally connecting an inner end of the first fixing part and one end of a mass member. A first elastic member having a portion, and a second fixing portion and a second fixing portion that are made of an elastic material and have an inner diameter smaller than the diameter of the rotating shaft, are fitted into the rotating shaft, are press-fitted, and are fastened and fixed by the fastening member. A dynamic damper comprising a second elastic member provided with a second connecting portion integrally connecting the inner end of the portion and the other end of the mass member, the outer ends of the first fixing portion and the second fixing portion. Is thinner than the first fixing part or the second fixing part and faces outward. Protrudes so that the inner diameter Te decreases is that the inner diameter of the tip is provided with a small hollow frustoconical blocking member from the first fixing portion or the second fixing portion.

[0009]

In the invention according to claim 1 configured as described above, the outer end of the second fixing portion projects outward so that its inner diameter is smaller than the inner diameter of the second fixing portion. With the hollow truncated cone-shaped blocking member, the rotating shaft is tightened by the blocking member more strongly and uniformly than the second fixing portion. As a result, if the elastic material experiences fatigue due to long-term use of the dynamic damper, the second
Even if there is a slight gap between the fixed portion and the rotary shaft, the rotary shaft is still strongly tightened by the blocking member, and no gap is created between the blocking member and the rotary shaft. Therefore, invasion of foreign matter such as moisture from the outside between the mass member and the rotating shaft is reliably prevented, and the performance of absorbing the harmful vibration by the dynamic damper is maintained. Further, since the blocking member has an inner diameter smaller than that of the second fixing portion, but has a wall thickness thinner than that of the second fixing portion, the blocking member is easily deformed when it is inserted into the rotary shaft. There is no loss of sex.

Further, in the invention according to claim 2 configured as described above, since the blocking member is also provided at the outer end of the first fixing portion which is clamped and fixed by the ring-shaped tightening member, the tightening member is secured. Even if a small gap is generated between the first fixed part and the rotary shaft due to the circumferential stress locally generated by the tightening, the rotary shaft is strongly and uniformly tightened on the outside by the blocking member. . As a result, invasion of moisture or the like from the outside into the space between the mass member and the rotating shaft is reliably prevented, and the drive shaft does not lose its harmful vibration absorbing performance. In addition, the blocking member,
The inner diameter is smaller than the inner diameter of the first fixing portion, but the wall thickness is thinner than that of the first fixing portion, so that it is easy to be deformed when it is inserted into the rotary shaft, and the workability of insertion is impaired. There is no.

Further, in the invention according to claim 3 configured as described above, since both the fixing portions are ring-shaped by providing the blocking members at the outer ends of the first fixing portion and the second fixing portion of the dynamic damper, respectively. Even if a slight gap is generated between the fixed portion and the rotary shaft when the rotary shaft is tightened and fixed by the cylindrical tightening member, the rotary shaft is strongly and uniformly tightened by the blocking member on the outer side thereof. As a result, invasion of moisture or the like from the outside into the dynamic damper is reliably prevented. Further, since the blocking member is formed thinner than each fixing portion, its inner diameter is smaller than that of each fixing portion, but it is easily deformed when it is inserted into the rotary shaft, so that the insertion workability is impaired. There is no.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a dynamic damper D according to the first embodiment, and FIG. 2 shows the dynamic damper D attached to a drive shaft S of an automobile. FIG. 3 is a schematic cross-sectional view showing the state. The dynamic damper D includes a cylindrical mass member 10, a cylindrical first elastic member 20 coaxially and integrally provided on the right end of the mass member, and a coaxial first member on the left end of the mass member 10. And a tubular second elastic member 30 that is provided in a specific manner. The mass member 10 is provided with a cylindrical body 11 made of metal such as a thick-walled steel pipe. The inner peripheral surface, the outer peripheral surface, and both end surfaces of the cylindrical body 11 are made of a rubber material such as natural rubber to have a thickness of about 1 mm. A coated rubber film 12 is provided. The inner diameter of the mass member 10 is about 3 mm larger than the outer diameter of the drive shaft S.

The first elastic member 20 is made of a rubber material such as natural rubber and has a cylindrical first fixing portion 21.
And a first connecting portion 22 which is provided between the mass member 10 and the first fixing portion 21 and which integrally connects the two together. The inner diameter of the first fixing portion 21 is smaller than the outer diameter of the drive shaft S by about 0.5 to 1.0 mm. Further, a fastening groove 21 a for mounting the ring-shaped fastening member 23 is formed on the outer periphery of the first fixing portion 21. The tightening member 23, as shown in FIG.
A ring portion 23a formed by processing a metal thin plate having a width substantially the same as the width of the fastening groove 21a into a circle is provided, and a fastening piece 23b folded back outward at one end of the ring portion 23a is integrally provided. . The inner side 23a1 of the other end of the ring portion 23a is welded to the outer side surface of the substantially middle portion of the tightening piece 23b. Also, tightening piece 2
When 3b is bent and overlapped on the outer peripheral surface of the ring portion 23a, fixing pieces 23c that are integrally projected outward are provided at both ends of the overlapping portion of the ring portion 23a with the tightening piece 23b. The fastening member 23 is configured such that the fastening piece 23b is bent toward the ring portion 23a so that the diameter thereof is smaller than the outer diameter of the first fixing portion 21. As a result, the first fixing portion 21 is firmly tightened and fixed to the drive shaft S. The second elastic member 30 is formed of a rubber material such as natural rubber, and has a cylindrical second fixing portion 31, a mass member 10, and a second member.
The second connecting portion 32 is provided between the fixing portions 31 and has a substantially hollow truncated cone shape that integrally connects the two. The inner diameter of the second fixing portion 31 is 0.5 more than the inner diameter of the first fixing portion 21.
It is formed to be smaller by about 1.5 mm.

At the left end of the second cylindrical member 30, a hollow truncated cone shaped blocking member 3 made of the same material as that of the second cylindrical member 30 is formed.
3 are integrally provided. The blocking member 33 is formed so as to be inclined so that the inner diameter becomes smaller from the connecting portion with the second cylindrical member 30 to the outer end portion, and the inner diameter of the tip portion is 1 to 3 mm from the inner diameter of the second cylindrical member 30. It has been made smaller. In addition, the blocking member 33 is formed so that the wall thickness thereof is thinner than the wall thickness of the second cylindrical member 30, and is gradually thinned from the connecting portion with the second cylindrical member 30 to the outer end portion. . The thickness of the blocking member 33 is the second
The target is set to 50% or less of the wall thickness of the cylindrical member 30.
However, the inner diameter and the wall thickness of the blocking member can be appropriately changed according to the application of the dynamic damper D and the like. For example, the wall thickness may be uniform, and the second cylindrical member 30
The inner diameter of the blocking member may be larger or smaller than the inner diameter of the second cylindrical member in the connecting portion to.

The dynamic damper D has the same outer shape as the outer shape of the dynamic damper D shown in FIG. 1, and a cylindrical cavity shown in FIG. The mass member 1 is provided at the center of a molding die (not shown) constituted by an inner die.
It is integrally formed by vulcanization molding with a rubber material such as natural rubber in a state where the cylindrical body 11 of 0 is set.

Next, the dynamic damper D is fitted onto the drive shaft S and press-fitted to drive the drive shaft S.
Place it at the position where the maximum vibration is generated. The first elastic member 20 is fixed to the drive shaft S by winding and tightening the tightening member 23 in the tightening groove 21 of the first elastic member 20. As a result, the dynamic damper D will not be displaced due to bending vibration, torsional vibration, or the like that occurs when the drive shaft S rotates. On the other hand, the inner diameter of the second elastic member 30 is smaller than the inner diameter of the first elastic member, and the tightening force for the drive shaft S is further strengthened. Therefore, the tightening member 23 can be omitted. As a result, it is possible to reduce the cost of parts and the number of assembling steps.

Even when the second elastic member 30 does not use the tightening member 23, even if a slight gap is generated between the rubber shaft and the drive shaft S due to long-term use. Second elastic member 30
Since the drive shaft S is evenly covered and strongly tightened by the blocking member 33 having a smaller inner diameter provided on the outer side, no gap is created between the blocking member 33 and the drive shaft S. Therefore, moisture and oil from the outside do not enter the gap between the inner peripheral surface of the mass member 10 and the drive shaft S, so that the resonance characteristics of the dynamic damper D are not impaired and the performance of eliminating harmful vibrations is eliminated. Is reliably retained.

Next, a second embodiment will be described with reference to the drawings. The dynamic damper D according to the second embodiment, as shown in FIG. 4, includes a first elastic member 40 and a second elastic member 5.
Both of them have a structure in which they are fastened and fixed by ring-shaped fastening members 44 and 54. The outer ends of the first elastic member 40 and the second elastic member 50 are respectively provided with the same hollow truncated cone-shaped blocking members 43 and 53 as shown in the first embodiment. Other configurations of dynamic damper D are
This is the same as the first embodiment.

In the second embodiment constructed as described above, since the blocking members 43 and 53 having inner diameters smaller than the inner diameters of the fixed portions 41 and 51 are provided, the drive shaft is provided outside the fixed portions 41 and 51. Since S is tightened uniformly and strongly, the blocking members 43, 53 and the drive shaft S
There is no gap between them. Therefore, in the dynamic damper D according to the present embodiment, when the fixing portion is tightened and fixed by the ring-shaped tightening members 44 and 54,
It is preferably used when a quick tightening operation is performed using an inexpensive tightening member having a simple structure. That is, FIG.
As shown in FIG. 4, even if there is a disadvantage that a circumferential force acts on the fixed portion 41, which causes a slight gap A between the fixed portion 41 and the drive shaft S, the blocking member 43 causes the fixed portion 41 to move to the outside. Has been cut off from. Therefore, invasion of moisture or the like from the outside into the gap between the mass member and the drive shaft is reliably prevented. Therefore, the resonance characteristic of the dynamic damper D is not impaired, and the harmful vibration elimination performance is reliably maintained. In addition, the blocking member shown in the second embodiment is the same as the first embodiment shown in the first embodiment.
You may make it attach to a fixed part. As a result, the effects described above can be obtained.

Next, modified examples of the blocking member shown in the first and second embodiments will be described with reference to the drawings. As shown in FIG. 6 (a), the blocking member 60 according to the modification has a ring-shaped convex portion 61 having a blade-shaped cross section whose inner surface is perpendicular to the axial direction and whose tip faces outward. Is. The number of convex portions 61 may be at least one. When the dynamic damper D having the blocking member 60 configured as described above is mounted on the drive shaft S, the drive shaft S
As shown in FIG. 6 (b), the plurality of convex portions 61 of the blocking member 60 are strongly tightened over a plurality of places. Therefore, the effect of blocking the entry of moisture or the like from the outside is further enhanced, and the reliability of the dynamic damper D is enhanced. The cross-sectional shape of the convex portion provided on the blocking member 60 is not limited to the above-mentioned blade shape, but may be, for example, FIGS.
As shown in FIG. 5, it may have any shape such as a triangle 62 or a semicircle 63.

The tightening member shown in each of the above embodiments is not limited to the one having the above-mentioned structure, and may be any member that is wound around the fixed portion in a ring shape. Further, in the above-mentioned embodiment, the example in which the dynamic damper is applied to the drive shaft of the automobile has been shown, but the dynamic damper can be applied to other kinds of rotary shafts.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a dynamic damper according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing a state in which the dynamic damper is fitted into a drive shaft and press-fitted.

FIG. 3 is a front view schematically showing a tightening member.

FIG. 4 is a cross-sectional view schematically showing a state in which the dynamic damper according to the second embodiment is fitted and press-fitted onto a drive shaft.

FIG. 5 is a cross-sectional view schematically showing an aspect in which a fastening member is attached to a fixed portion.

FIG. 6 is a sectional view partially showing a blocking member according to a modification and a mounting state of the blocking member on a drive shaft.

FIG. 7 is a sectional view schematically showing a dynamic damper according to a conventional example.

[Explanation of symbols]

10 ... Mass member, 11 ... Cylindrical body, 12 ... Rubber film, 2
0 ... 1st elastic member, 21 ... 1st fixed part, 22 ... 1st connection part, 23 ... Tightening member, 30 ... 2nd elastic member, 31 ...
2nd fixing | fixed part, 32 ... 2nd connection part, 33 ... Blocking member, 40
... first elastic member, 43 ... blocking member, 44 ... tightening member, 50 ... second elastic member, 53 ... blocking member, 54 ... tightening member, D ... dynamic damper, S ... drive shaft.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Haruo Nakamura Inventor Haruo 5-3-8, Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Akihiko Nishimura 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Automotive Industry Co., Ltd.

Claims (3)

[Claims] 1. A cylindrical mass member having an inner diameter larger than the diameter of the rotary shaft and inserted through the rotary shaft, and an inner diameter smaller than the diameter of the rotary shaft and made of an elastic material, and fitted into the rotary shaft. A cylindrical first fixing part that is press-fitted and fixed by a tightening member, and a first connecting part that integrally connects an inner end of the first fixing part and one end of the mass member are provided. A first elastic member, a second fixed part made of an elastic material and having an inner diameter smaller than the inner diameter of the first fixed part and fitted into the rotary shaft and press-fitted; an inner end of the second fixed part; and the mass member. And a second elastic member provided with a second connecting portion that integrally connects the other end of the second fixing portion to the outer end of the second fixing portion, which is thinner than the second fixing portion. The inner diameter of the tip of the second fixing portion Dynamic damper characterized in that a small hollow frustoconical shutoff member than the diameter. 2. The dynamic damper according to claim 1, wherein an outer end of the first fixing portion is made of an elastic material, is thinner than the first fixing portion, and has an inner diameter that decreases toward the outside. A dynamic damper characterized in that a hollow truncated cone-shaped blocking member is provided which projects and has an inner diameter at the tip smaller than the inner diameter of the first fixing portion. 3. A cylindrical mass member having an inner diameter larger than the diameter of the rotating shaft and inserted through the rotating shaft, and an inner diameter smaller than the diameter of the rotating shaft and made of an elastic material and fitted into the rotating shaft. A first elastic member provided with a first fixing portion that is press-fitted together and fixed by a tightening member, and a first connecting portion that integrally connects an inner end of the first fixing portion and one end of the mass member. A second fixing part, which is made of an elastic material and has an inner diameter smaller than that of the rotating shaft, is fitted into the rotating shaft, is press-fitted, and is fixed by a tightening member; and an inner end of the second fixing part. A dynamic damper comprising: a second elastic member provided with a second connecting portion that integrally connects the other end of the mass member to the outer end of the first fixing portion and the second fixing portion. It is thinner than the 1st fixing part or the 2nd fixing part, and its inner diameter toward the outside Small so as protrude, dynamic damper, wherein the inner diameter of the tip is provided with the first fixing portion or the small hollow frustoconical blocking member from the second fixing unit.