JPH04300435A - Dynamic damper - Google Patents

Abstract

PURPOSE:To improve the durability of spring portions. CONSTITUTION:At a dynamic damper having a rotary body 1 and a mass body 2 and spring portions 3, the mass body 2 is constituted with an outer ring 20 and an inner ring 21 whose diameter is contracted and which is arranged in the outer ring 20. With the diameter contraction of the inner ring 21, preliminarily compressed spring portion durability is improved at spring portions 3, and at the same time the outer periphery portion of the inner ring 21 is press-welded against the inner periphery portion of the outer ring 20.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic damper. This dynamic damper can be applied, for example, to damping harmful vibrations in rotating shafts such as propeller shafts and drive shafts of automobiles.

0002

[Prior Art] Conventionally, as a dynamic damper,
As disclosed in Japanese Utility Model Application Publication No. 62-69645, etc., a rotating body that is attached to a rotating shaft and rotates around the axis, and a ring-shaped mass body that is arranged approximately coaxially around the rotating body. It is known to have a spring part made of a rubber material that connects the outer circumferential part of the rotating body and the inner circumferential part of the mass body.

In the above-mentioned dynamic damper, the mass body resonates via the spring portion in the harmful vibration region, and thereby the harmful vibration transmitted to the rotating body is damped. The harmful vibration damping performance of this dynamic damper is basically determined by the mass of the mass body and the spring constant of the spring portion in the vibration direction.

0004

In the dynamic damper described above, the spring portion made of a rubber material is vulcanized with the outer circumferential portion of the rotating body connected to the inner circumferential portion of the mass body. Therefore, tensile stress is generated in the spring part due to shrinkage of the rubber material accompanying the vulcanization process, and there is a limit to the improvement in the durability of the spring part.

[0005] Therefore, when the conventional dynamic damper is used for a long time, it cannot be expected to provide the necessary harmful vibration damping force. The present invention was developed in view of the above circumstances, and its purpose is to provide a dynamic damper that is advantageous in improving the durability of the spring portion and can maintain harmful vibration damping force for a long period of time. .

[0006]

[Means for Solving the Problems] The dynamic damper of the present invention includes a rotating body that rotates around an axis, a ring-shaped mass body that is arranged approximately coaxially around the rotating body, and a rotating body that rotates with the mass body. The mass body is composed of an outer ring having an inner circumferential part that defines a central hole, and a spring part that is arranged inside the outer ring to reduce its diameter in the radial direction. It is characterized in that the spring portion is compressed in the radial direction as the diameter is reduced, and that the outer circumferential portion is formed by an inner ring that is crimped onto the inner circumferential portion of the outer ring.

[0007] Diameter dimensions and axial length dimensions of the outer ring and inner ring,
The weight can be set as appropriate. The material of the outer ring and the inner ring can be selected as appropriate, and may be, for example, steel-based, aluminum-based, etc. The inner ring may have a continuous structure in the circumferential direction as illustrated in FIG. 3, which will be described later, or may have a divided structure, as illustrated in FIG. 7, which will be described later. The spring portion is usually made of rubber material.

[0008] In order to reduce the diameter of the inner ring in the radial direction and place it inside the outer ring, the inner ring may be drawn and press-fitted into the outer ring, or the inner ring may be drawn and then inserted into the outer ring. It may be press-fitted. The amount by which the diameter of the inner ring is reduced can be, for example, 1 to 4, when the length in the radial direction of the spring portion before diameter reduction is 10.

[0009]

[Operation] In the dynamic damper of the present invention, the inner ring and outer ring of the mass body resonate through the radially compressed spring portion in the harmful vibration region, thereby damping the harmful vibration. In the dynamic damper of the present invention, as the diameter of the inner ring decreases, the outer circumference of the inner ring is pressed against the inner circumference of the outer ring, so the integrity of the inner ring and the outer ring that constitute the mass body increases. .

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment of a dynamic damper according to the present invention will be described below with reference to FIGS. 1 to 4. As shown in FIG. 3, this dynamic damper consists of a rotating body 1 that rotates around an axis P, a circular ring-shaped mass body 2 that is arranged approximately coaxially around the rotating body 1, and a rotating body 1 that rotates around an axis P. It consists of a rubber spring part 3 vulcanized and bonded to the outer periphery and the inner periphery of the mass body 2, and a rubber stopper part 4 vulcanized and bonded to the outer periphery of the rotating body 1. Note that an appropriate number of attachment holes 10 are formed in the rotating body 1. A gap 4a is formed between the stopper part 4 and the mass body 2.

The mass body 2 includes a thick outer ring 20 made of cast iron.
and a thin inner ring 21 made of steel. As shown in FIG. 2, the outer ring 20 has an inner peripheral portion 2 that partitions the central hole 20a.
Has 0b. As shown in FIG. 1, the inner peripheral part 21 of the inner ring 21
The end portion 3a of the spring portion 3 is vulcanized and bonded to a. Here, in the state shown in FIG. 3, the inner ring 21 has been reduced in diameter by a required amount in the radial direction, and the outer circumference 21b of the inner ring 21 is crimped to the inner circumference 20b of the outer ring 20. As the diameter of the inner ring 21 decreases, the spring portion 3 is precompressed in the radial direction.

By the way, in the dynamic damper of this embodiment, as shown in FIG. It is manufactured by press-fitting the inner ring 21 of the assembled body 6 into the center hole 20a of the outer ring 20 and reducing the diameter of the inner ring 21 using a jig. If the radial length H1 of the spring portion 3 before press-fitting is 20, then the inner ring 2 before press-fitting is
The outer diameter r1 of the outer ring 20 is 120, and the inner diameter r2 of the outer ring 20 is 116. Here, in the state shown in FIG. 1, the spring part 3 of the assembled body 6 has been vulcanized, and therefore, due to shrinkage of the rubber material due to the vulcanization process, the spring part 3 of the assembled body 6 shown in FIG. , tensile stress is acting in the length direction. However, as described above, when the inner ring 21 of the assembly 6 is press-fitted into the outer ring 20, the diameter of the inner ring 21 is reduced, and as the diameter is reduced, the spring portion 3 is moved in its length direction, that is, in the radial direction of the dynamic damper. Pre-compressed.

When using the dynamic damper of this embodiment, the rotating body 1 is attached to a rotating shaft (not shown). When the rotating shaft rotates in the direction of arrow A in this state, the rotating body 1 and mass body 2 forming the dynamic damper also rotate in the same direction. At this time, the outer ring 2 of the mass body 2 in the harmful vibration range
0 and the inner ring 21 resonate through the spring portion 3, thereby damping harmful vibrations of the rotating shaft. Note that the damping performance of harmful vibrations is basically determined by the spring constant of the spring portion 3 in the vibration direction, and the inner ring 21 and outer ring 2 that constitute the mass body 2.
It is determined by the mass of 0.

Furthermore, when there is an excessive relative displacement between the rotating body 1 and the mass body 2 in the radial direction, the outer surface 4c of the stopper portion 4 comes into contact with the inner peripheral portion 21a of the inner ring 21 of the mass body 2, thereby preventing the excessive displacement. can be suppressed. As explained above, in the dynamic damper of this embodiment, the spring portion 3 is pre-compressed in the radial direction, so that the durability of the spring portion 3 is improved. Therefore, even under severe usage conditions, the life of the dynamic damper is improved. Furthermore, the dynamic damper of this embodiment has a structure in which the spring portion 3 is pre-compressed by reducing the diameter of the inner ring 21, and the outer diameter of the outer ring 20 is not substantially changed, so the outer diameter size of the dynamic damper is kept constant. can be maintained without compromising the size or equipment of the dynamic damper.

Note that in the first embodiment described above, the inner ring 2
Although no slit is formed in the inner ring 21, depending on the material, size, etc. of the inner ring 21, in order to ensure the diameter reduction property of the inner ring 21, a slit may be formed in the peripheral wall of the inner ring 21 almost parallel to the axial direction. It can also be formed. (Second Embodiment) Next, the second embodiment of the dynamic damper of the present invention
An example will be explained based on FIG. In this example, the axial length of the inner ring 21 is made longer than in the first embodiment, and the axial end of the inner ring 21 is bent radially outward into a flange shape by caulking to form the stopper portion 21f. are doing. Since the stopper portion 21f faces and locks the end surface 20f of the outer ring 20, the resistance to falling off of the outer ring 20 can be improved. (Third Example) Next, the third example of the dynamic damper of the present invention
An embodiment will be described based on FIGS. 6 to 8. The dynamic damper of the third embodiment basically has the same configuration as the first embodiment. Therefore, parts that basically perform the same functions are given the same reference numerals.

The mass body 2 of the third embodiment consists of a thin outer ring 20 made of steel and an inner ring 21 made of thick steel. As shown in FIG. 7, the inner ring 21 has thick-walled divided bodies 21g, 21h, 21i, 21j, 21 divided in the circumferential direction.
It is composed of k. In the state before press-fitting shown in FIG. 7, a gap 21m is formed between the divided bodies 21g to 21k.

In the third embodiment, the divided bodies 21g~ of the inner ring 21 are arranged in the direction of reducing the gap 21m of the assembled body 6 shown in FIG.
The inner ring 21 is manufactured by press-fitting the inner ring 21 into the center hole 20a of the outer ring 20 while bringing the inner ring 21k closer to each other to reduce the diameter of the inner ring 21. If the radial length H2 of the spring portion 3 before press-fitting is 12.5, the outer circumference r3 of the diameter of the inner ring 21 before press-fitting is 120, and the inner circumference r4 of the diameter of the outer ring 20 is 115. be. After press-fitting, as shown in FIG. 6, both ends of the outer ring 20 in the axial direction are caulked to form a stopper portion 21f.

In the state shown in FIG. 7, the spring portion 3 of the assembled body 6 has been vulcanized. However, as described above, by reducing the diameter of the divided bodies 21g to 21k in the direction of reducing the gap 21m between the divided bodies 21g to 21k of the assembled body 6, the inner ring 2
1 into the outer ring 20, as the diameter of the inner ring 21 decreases, the spring part 3 is pre-compressed in its length direction, that is, in the radial direction of the dynamic damper, and the repulsive force of the spring part 3 causes the inner ring to compress. The outer peripheral part 21b of 21 is the outer ring 2
It is crimped onto the inner peripheral portion 20b of 0. (Fourth embodiment) Next, the fourth embodiment of the dynamic damper of the present invention
An example will be described based on FIG. The dynamic damper of the fourth embodiment basically has the same configuration as that of the third embodiment. However, in this example, the divided bodies 21g to 21k are connected to each other by a rubber connecting portion 21p. Connection part 21
p regulates the independent displacement of the divided bodies 21g to 21k during press-fitting.

[0019]

[Effects of the Invention] According to the dynamic damper of the present invention,
Since the spring portion is compressed in the radial direction, the durability of the spring portion can be improved. Further, according to the dynamic damper of the present invention, the spring portion is compressed by reducing the diameter of the inner ring, and the outer diameter of the outer ring is not substantially changed, so the outer diameter size of the dynamic damper can be maintained constant. Does not impair the size or equipment of the dynamic damper.

[Brief explanation of drawings]

FIG. 1 is a plan view of an assembled body constituting a dynamic damper of a first embodiment.

FIG. 2 is a plan view of an outer ring constituting the dynamic damper of the first embodiment.

FIG. 3 is a plan view of the dynamic damper of the first embodiment.

FIG. 4 is a cross-sectional view of essential parts of the dynamic damper of the first embodiment.

FIG. 5 is a sectional view of a main part of a dynamic damper according to a second embodiment.

FIG. 6 is a sectional view of main parts of a dynamic damper according to a third embodiment.

FIG. 7 is a plan view of an assembled body constituting a dynamic damper of a third embodiment.

FIG. 8 is a plan view of an outer ring constituting the dynamic damper of the third embodiment.

FIG. 9 is a plan view of an assembled body constituting the dynamic damper of the fourth embodiment.

[Explanation of symbols]

1 Rotating body 2 Mass body 20 Outer ring 21 Inner ring 3 Spring part

Claims (1)

[Claims] Claim 1: A rotating body that rotates around an axis, a ring-shaped mass body disposed approximately coaxially around the rotating body, and a mass body that connects the mass body and the rotating body. The mass body is composed of an outer ring having an inner peripheral part that partitions a central hole, and a spring part that is arranged inside the outer ring to reduce its diameter in the radial direction. A dynamic damper comprising: a spring portion compressed in the radial direction; and an inner ring having an outer circumferential portion crimped to an inner circumferential portion of the outer ring.