JP3076718B2 - Dynamic damper - Google Patents

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 rotating shaft such as a drive shaft of an automobile and suppresses harmful vibrations such as bending vibration and torsional vibration occurring on the rotating shaft.

[0002]

2. Description of the Related Art Conventionally, as a dynamic damper of this type, as disclosed in Japanese Patent Application Laid-Open No. Hei 2-62442, for example, both ends of a cylindrical mass member 1 having an inner diameter larger than the outer diameter of a rotating shaft such as a drive shaft. In addition, there has been known a structure in which a cylindrical fixing portion 3 having an inner diameter smaller than the outer diameter of the rotary shaft is integrally connected via a hollow truncated conical connecting portion 2 made of an elastic material such as rubber. The fixed portion 3 is fitted to the rotating shaft and press-fitted to a predetermined position. Further, the dynamic damper is made of metal or resin. The band was wound around and fixed to the rotating shaft (see FIG. 7A).

[0003] Other dynamic dampers include:
As shown in Japanese Utility Model Laid-Open Publication No. 3-25048, the structure is the same as that of the above-mentioned dynamic damper, and the fixing portion 4 on one side is provided.
Is made smaller than the inner diameter of the other fixing part 5, and the fixing of the fixing part to the rotating shaft by the band is performed by the other fixing part 5.
The only one known was known (see FIG. 7 (b)). In this dynamic damper, the inner peripheral surface of the fixed part is uniformly and tightly brought into contact with the rotating shaft by a strong tightening force of the fixed part 4 on one end side having a small inner diameter. The occurrence of gaps 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 rotating shaft is suppressed, and the reliability of the dynamic damper is ensured. Further, by adopting such a configuration, the cost of parts is reduced, and the assembling workability is improved. When each of the dynamic dampers generates harmful vibration due to rotation of the rotating shaft, the mass member 1 having a unique frequency corresponding to the frequency of the harmful vibration is transmitted through the coupling portion 2. By resonating, the vibration is converted into vibration energy and absorbed.

[0004]

However, in the case of the above-mentioned dynamic damper, however, it is often a harsh use environment in which it is usually used near the surface of the earth and is exposed to the outside air. 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 by the band and the rotating shaft, and moisture or the like enters from outside into the gap between the mass member of the dynamic damper and the rotating shaft, and 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 increase the radial tightening force by making the inner diameter of the fixing portion smaller, but the resistance when the fixing portion is fitted and press-fitted to the rotating shaft becomes large, and the dynamic There is a problem that the work of press-fitting the damper into the rotating shaft becomes very difficult.

[0005] Further, in the case where the band is fastened by a band like the above-mentioned fixed portion on the other end side or the fixed portion on both end sides of the former dynamic damper, the tightening is performed in a short time using an inexpensive band. In this case, the uniformity of the tightening force becomes insufficient. For example, as shown in FIG. 5, a circumferential stress is applied to a part of the fixing part, and the part slightly lifts up from the rotating shaft to generate a gap. Sometimes. Then, there is a problem that moisture or the like in the external atmosphere enters the gap between the mass member of the dynamic damper and the rotating shaft from the gap. An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a dynamic damper that prevents invasion of moisture and the like from the outside and has a simple configuration.

[0006]

In order to achieve the above object, a structural feature of the invention according to the first aspect is that a cylindrical member having an inner diameter larger than the diameter of the rotating shaft and inserted through the rotating shaft. And a cylindrical first fixing portion which is made of an elastic material, has an inner diameter smaller than the diameter of the rotating shaft, is fitted into the rotating shaft, is press-fitted, and is fixedly fastened by the fastening member, and an inner end of the first fixing portion. A first connecting member for integrally connecting the first member and one end of the mass member; and a press fit into the rotating shaft having an inner diameter smaller than the inner diameter of the first fixing portion and made of an elastic material. A dynamic damper comprising: a second fixing portion; and a second elastic member provided with a second connecting portion integrally connecting the inner end of the second fixing portion and the other end of the mass member.
At the outer end of the fixing portion, a blocking member in the form of a truncated hollow cone, which is thinner than the second fixing portion and protrudes outward so that its inner diameter becomes smaller, and whose inner diameter at the tip is smaller than the inner diameter of the second fixing portion, is provided. It is in.

According to a second aspect of the present invention, in the dynamic damper according to the first aspect, the outer end of the first fixing portion is made of an elastic material and is thinner than the first fixing portion. In addition, there is provided a blocking member in the shape of a truncated cone of a cone protruding outward so as to have a smaller inner diameter and having an inner diameter at the tip smaller than the inner diameter of the first fixing portion.

[0008]

According to the first aspect of the present invention, the outer end of the second fixing portion projects outward so that its inner diameter becomes smaller than the inner diameter of the second fixing portion. With the hollow truncated cone-shaped blocking member, the rotation shaft is more strongly and uniformly tightened by the blocking member than the second fixing portion. As a result, if sag occurs in the elastic material due to long-term use of the dynamic damper, the second
Even if a slight gap may be generated between the fixed portion and the rotating shaft, the rotating shaft is still strongly tightened by the blocking member, and no gap is generated between the blocking member and the rotating shaft. Therefore, intrusion 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, the blocking member has an inner diameter smaller than the inner diameter of the second fixed portion, but is formed to be thinner than the second fixed portion, so that it is easy to deform when inserted into the rotating shaft. Sex is not impaired.

Further, in the invention according to claim 2 configured as described above, the blocking member is also provided at the outer end of the first fixing portion which is tightened and fixed by the ring-shaped tightening member. Even if a small gap is generated between the first fixed portion and the rotating shaft due to a circumferential stress locally generated by the fastening, the rotating shaft is strongly and uniformly tightened by the blocking member outside the first fixed portion and the rotating shaft. . As a result, intrusion of moisture or the like from the outside between the mass member and the rotating shaft is reliably prevented, and the performance of absorbing harmful vibrations by the drive shaft is not impaired. In addition, the blocking member,
Although the inner diameter is smaller than the inner diameter of the first fixed portion, the thickness is formed thinner than the first fixed portion, so that it is easily deformed when inserted into the rotating shaft, and the workability of insertion is impaired. There is no.

[0010]

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 a first embodiment, and FIG. 2 shows that the dynamic damper D is mounted on a drive shaft S of an automobile. FIG. 2 is a schematic view showing a state in which it is closed. 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 and integral coaxial member on the left end of the mass member 10. And a cylindrical second elastic member 30 which is provided in a fixed manner. The mass member 10 is provided with a metal cylindrical body 11 such as a thick steel pipe. The inner peripheral surface, the outer peripheral surface, and both end surfaces of the cylindrical body 11 are formed to a thickness of about 1 mm by a rubber material such as natural rubber. 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 formed of a rubber material such as natural rubber, and has a cylindrical first fixing portion 21.
And a first connecting portion 22 provided between the mass member 10 and the first fixing portion 21 and having a substantially hollow truncated cone shape and integrally connecting the two. The inner diameter of the first fixing portion 21 is formed to be smaller than the outer diameter of the drive shaft S by about 0.5 to 1.0 mm. On the outer periphery of the first fixing portion 21, a fastening groove 21a for attaching the ring-shaped fastening member 23 is formed. The fastening member 23, as shown in FIG.
A ring portion 23a formed by processing a thin metal plate having a width substantially equal to the width of the fastening groove 21a into a circular shape is provided, and a fastening piece 23b that is folded outward at one end of the ring portion 23a is provided integrally. . The inside 23a1 of the other end of the ring portion 23a is welded to the outer surface of a substantially intermediate portion of the fastening piece 23b. In addition, fastening piece 2
A fixing piece 23c integrally protruding outward is provided at both ends of the overlapping portion of the ring portion 23a with the fastening piece 23b when the 3b is folded and overlapped on the outer peripheral surface of the ring portion 23a. The fastening member 23 is configured such that its diameter is smaller than the outer diameter of the first fixing portion 21 by bending the fastening piece 23b toward the ring portion 23a. Thereby, the first fixing portion 21 is firmly 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
A substantially hollow truncated conical second connecting portion 32 is provided between the fixing portions 31 and integrally connects the both. The inner diameter of the second fixing part 31 is 0.5 more than the inner diameter of the first fixing part 21.
It is formed so as to be about 1.5 mm smaller.

At the left end of the second cylindrical member 30, a blocking member 3 having the same material as the second cylindrical member 30 and having a truncated hollow cone shape is provided.
3 are provided integrally. The blocking member 33 is formed so as to be inclined so that its inner diameter becomes smaller from the connection portion with the second cylindrical member 30 to the outer end portion, and the inner diameter of the distal end portion is 1 to 3 mm from the inner diameter of the second cylindrical member 30. It is about small. Further, the blocking member 33 is formed to be thinner than the thickness of the second cylindrical member 30 and to be gradually thinner from a portion connected to the second cylindrical member 30 to an outer end portion. . The thickness of the blocking member 33 is
50% or less of the thickness of the cylindrical member 30 is set as a guide.
However, the inner diameter and thickness of the blocking member can be changed as appropriate according to the use of the dynamic damper D and the like. For example, the 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 at the connecting portion.

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

Next, the dynamic damper D is fitted to the drive shaft S and press-fitted.
Is placed at the position where the vibration of the maximum is obtained. Then, 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. This prevents the dynamic damper D from being displaced by bending vibration, torsional vibration, or the like generated when the drive shaft S rotates. On the other hand, since the inner diameter of the second elastic member 30 is smaller than the inner diameter of the first elastic member, and the tightening force on the drive shaft S is further strengthened, the tightening member 23 can be omitted. As a result, it is possible to reduce the parts cost and the number of assembling steps.

By not using the tightening member 23 for the second elastic member 30, even if the rubber material is set for a long time and a slight gap is formed between the second elastic member 30 and the drive shaft S, Second elastic member 30
Since the drive shaft S is more uniformly covered and strongly tightened by the blocking member 33 having a smaller inner diameter provided outside, no gap is formed between the blocking member 33 and the drive shaft S. Accordingly, since moisture or oil from the outside does not enter the gap between the inner peripheral surface of the mass member 10 and the drive shaft S, the resonance characteristics of the dynamic damper D are not impaired, and the harmful vibration elimination performance can be prevented. Is securely held.

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

In the second embodiment constructed as described above, since the blocking members 43, 53 having an inner diameter smaller than the inner diameters of both the fixing portions 41, 51 are provided, the drive shaft is provided outside the fixing portions 41, 51. S is tightened uniformly and strongly, so that the blocking members 43 and 53 and the drive shaft S
There is no gap between them. For this reason, the dynamic damper D according to the present embodiment has a structure in which the fixing portion is tightened and fixed by the ring-shaped tightening members 44 and 54.
It is suitably used when a quick tightening operation is performed using an inexpensive tightening member having a simple configuration. That is, FIG.
As shown in FIG. 7, even if there is a disadvantage that a circumferential force acts on the fixing portion 41 and thus a slight gap A is generated between the fixing portion 41 and the drive shaft S, the fixing member 41 is Are shielded from Therefore, intrusion 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 characteristics of the dynamic damper D are not impaired, and the harmful vibration elimination performance is reliably maintained. The blocking member shown in the second embodiment is replaced with the first member shown in the first embodiment.
You may make it attach to a fixed part. Thereby, the above-described effects can be obtained.

Next, a modification 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), a blocking member 60 according to a modified example has a ring-shaped convex portion 61 having a blade-shaped cross section with its tip directed outward in the axial direction perpendicular to the inner peripheral surface. It is. The number of the protrusions 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. 6B, is strongly tightened at a plurality of locations by a plurality of projections 61 of the blocking member 60. Therefore, the effect of blocking the entry of moisture and the like from the outside is further enhanced, and the reliability of the dynamic damper D is enhanced. The cross-sectional shape of the projection provided on the blocking member 60 is not limited to the above-mentioned blade shape, and is, for example, shown in FIGS.
As shown in the figure, the shape may be an arbitrary shape such as a triangle 62 and a semicircle 63.

The fastening member shown in each of the above embodiments is not limited to the above-described structure, but may be any member that can be used by being wound around a fixed portion in a ring shape. Further, in the above-described embodiment, an example in which the dynamic damper is applied to a drive shaft of an automobile has been described. However, the dynamic damper can be applied to other types of rotating shafts.

[Brief description of the 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 fastening member.

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

FIG. 5 is a cross-sectional view schematically showing an aspect in which a fastening member is mounted on a fixing portion.

FIG. 6 is a sectional view partially showing a blocking member according to a modified example and a state where the blocking member is mounted on a drive shaft.

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

[Explanation of symbols]

Reference numeral 10: mass member, 11: cylindrical body, 12: rubber film, 2
0: first elastic member, 21: first fixing portion, 22: first connecting portion, 23: fastening member, 30: second elastic member, 31 ...
2nd fixing | fixed part, 32 ... 2nd connection part, 33 ... blocking member, 40
... 1st elastic member, 43 ... blocking member, 44 ... fastening member, 50 ... 2nd elastic member, 53 ... blocking member, 54 ... fastening member, D ... dynamic damper, S ... drive shaft.

Continued on the front page (72) Inventor Haruo Nakamura 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Akihiko Nishimura 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors (56) References JP-A-2-154827 (JP, A) JP-A-61-167778 (JP, A) JP-A-3-25049 (JP, U) JP-A-5-92577 (JP) , U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F16F 15/12-15/30 B60K 17/22

Claims (2)

(57) [Claims] 1. A cylindrical mass member having an inner diameter larger than the diameter of the rotating shaft, and a cylindrical mass member inserted through the rotating shaft, and made of an elastic material and having an inner diameter smaller than the diameter of the rotating shaft and fitted to the rotating shaft. A cylindrical first fixing portion which is press-fitted and fastened and fixed by a fastening member; and a first connecting portion for integrally connecting an inner end of the first fixing portion and one end of the mass member. A first elastic member, a second fixed portion made of an elastic material, having an inner diameter smaller than the inner diameter of the first fixed portion, fitted to the rotary shaft and press-fitted, an inner end of the second fixed portion, and the mass member A second elastic member provided with a second connecting portion for integrally connecting the other end of the second fixed portion with the second elastic portion. An outer end of the second fixed portion is thinner than the second fixed portion. The inner diameter of the second fixed portion is projected outwardly so that its inner diameter becomes smaller. 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 outward. A dynamic damper, comprising: a protruding hollow truncated cone-shaped blocking member having an inner diameter of a tip that is smaller than an inner diameter of the first fixed portion.