JPH0231626Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a dynamic damper, and in particular to a dynamic damper that effectively reduces vibrations on a predetermined rotating shaft such as a drive shaft by being attached to the rotating shaft. This concerns the Mitsuku damper.

(Prior Art) Conventionally, in a rotating shaft such as a drive shaft used to transmit rotational driving force to a predetermined engine or to support a predetermined rotating body, vibrations are transmitted from the connected engine or the outside. In the case of an input, a dynamic damper that can function as a dynamic vibration absorber is attached to the rotating shaft to absorb and reduce vibrations caused by the rotating shaft, thereby reducing the vibration caused by the rotating shaft. A structure is adopted that prevents the transmission of noise and suppresses the stress amplitude of the rotating shaft to prevent fatigue damage.

Incidentally, a dynamic damper used for such a purpose usually includes a cylindrical part attached to a predetermined rotating shaft and a flange extending radially outward from the outer peripheral surface of the cylindrical part for a predetermined length. It has a structure in which a damper mass of a predetermined weight is integrally arranged on the radial outer peripheral edge of an elastic body consisting of a shaped support part, and vibrations at the rotation axis (main vibration system) are provided. However, by tuning the natural frequency of the dynamic damper (auxiliary vibration system) and causing resonance, such vibrations can be absorbed and reduced.

However, since the vibrations generated in such a rotating shaft have different frequencies in the axial direction and in the direction perpendicular to the axis, in a dynamic damper having the above-described structure, the vibration is formed in a flange shape. By adjusting the rubber properties of the supporting part and the weight of the damper mass, the resonance frequencies of the damper in the axial direction and the axis-perpendicular direction are adjusted to the axial and axis-perpendicular vibration frequencies that are aimed at reducing the rotary shaft. By synchronizing, vibrations in the rotating shaft are absorbed,
Measures are being taken to reduce it.

Therefore, in a dynamic damper that takes such measures, one damper mass is shared as a damper mass for vibrations in both directions when setting the resonance frequency in the axial direction and the direction perpendicular to the axis. This is achieved by changing the spring characteristics of the elastic body support in the axial direction and in the direction perpendicular to the axis.
In short, deformation of the elastic support is caused by shear in response to vibration in the axial direction, and compression in response to vibration in the direction perpendicular to the axis. By adjusting the spring characteristics, the resonant frequencies of the damper in the axial direction and in the axis-perpendicular direction can be set, thereby effectively responding to different frequencies of vibration in the axial direction and in the axis-perpendicular direction on a given rotating shaft. This results in a functional vibration absorber.

(Problem) However, in such conventional dynamic dampers, as mentioned above, deformation in the elastic support part is caused by compression in response to vibration in the direction perpendicular to the axis, but deformation in the direction perpendicular to the axis is caused by compression. Vibration is generated by shear, but since the spring coefficient of an elastic body is larger in compression than in shear,
The axial resonant frequency of such a damper is
It was not possible to set the resonance frequency higher than the resonance frequency in the direction perpendicular to the axis.

Therefore, in the case of conventional dynamic dampers, for a rotating shaft where the frequency to be reduced is larger in the axial direction than the frequency in the direction perpendicular to the axis, It was not possible to effectively function as a vibration absorber against vibrations, and it was impossible to provide a dynamic damper that exerts an effective vibration absorbing effect on such a rotating shaft.

(Solution Means) Here, the present invention was made against the background of the above-mentioned circumstances, and its feature is that by being attached to a predetermined rotating shaft, vibrations on the rotating shaft can be prevented. In the above-mentioned dynamic damper, which aims to reduce the An L-shaped elastic support part consisting of a radial part extending for a predetermined length and an axial part extending for a predetermined length in the axial direction from the end of the radial part is integrally provided, and the The structure is such that a damper mass having a predetermined weight is integrally provided on the free end side portion of the axial portion.

(Function/Effect) Therefore, in the dynamic damper having the structure according to the present invention, deformation of the elastic support part in response to vibration in the direction perpendicular to the axis is caused by shearing in the axial part, while The deformation of the elastic support part in response to directional vibrations is caused by compression in the axial part and shearing in the radial part.

In other words, according to the present invention, it is possible to easily set the resonance frequency in the axial direction of the dynamic damper to be higher than the resonance frequency in the direction perpendicular to the axis, thereby making it possible to set the resonance frequency of the dynamic damper higher than the resonance frequency in the direction perpendicular to the axis. This makes it possible to easily provide a dynamic damper that can effectively act as a dynamic vibration absorber for a rotating shaft where the frequency in the direction is greater than the frequency in the direction perpendicular to the axis.

(Example) In order to clarify the present invention more specifically, an example having a structure according to the present invention will be described below.
This will be explained in detail with reference to the drawings.

First, FIGS. 1 and 2 show an embodiment of a dynamic damper having a structure according to the present invention.

In these figures, reference numeral 10 denotes an elastic body made of a predetermined rubber material, and has a cylindrical portion 14 having a substantially cylindrical shape attached to a predetermined rotating shaft 12 such as a drive shaft in the center thereof. There is. A band groove 16 extending in the circumferential direction is provided on the outer peripheral surface of the cylindrical portion 14 near one end in the axial direction, and the cylindrical portion 14 is fitted around the rotating shaft 12. In this state, a tightening band (not shown) is attached to the outer peripheral surface of the band groove 16, so that the cylindrical portion 14 can be firmly fixed to the rotating shaft 12. ing.

Further, on the outer circumferential surface of the cylindrical portion 14 of the elastic body 10, an elastic support portion 18 extending in the circumferential direction and having an L-shaped cross section is integrally formed at approximately the center of the cylindrical portion 14 in the axial direction. The cylindrical portion 14
The elastic body 10 is composed of the elastic support portion 18 and the elastic support portion 18 .

More specifically, the elastic support portion 18 is connected to the cylindrical portion 14
a flange-shaped radial part 20 extending radially outward for a predetermined length from the outer peripheral surface of the radial part 20; and a cylindrical axial portion 22 extending a predetermined length.

A ring-shaped damper mass 24 having a rectangular cross section is disposed at the free end side of the axial portion 22 of the elastic support portion 18, and is buried within the axial portion 22. Therefore, it is integrally held at a position spaced a predetermined distance radially outward from the outer circumferential surface of the cylindrical portion 14.

In the dynamic damper having such a structure, the deformation of the elastic support portion 18 due to the displacement of the damper mass 24 in the direction perpendicular to the axis is
On the other hand, deformation in response to the axial displacement of the damper mass 24 is caused by compression of the elastic body in the axial portion 22 and shearing of the elastic body in the radial portion 20. It happens. Since the spring modulus of an elastic body is smaller in shear than in compression, it may be possible to set the resonance frequency in the axial direction of the dynamic damper to be larger than the resonance frequency in the direction perpendicular to the axis. be.

That is, by shortening the length of the radial portion 20 where the deformation in response to the axial displacement of the damper mass 24 is caused by shearing, or by shortening the length of the radial portion 20 in which the deformation in response to the axial displacement of the damper mass 24 is caused by compression. By increasing the length of the axial portion 22 where deformation in response to displacement in the direction perpendicular to the axis is caused by shearing, it is possible to easily set the axial resonant frequency to be higher than the radial resonant frequency. Therefore, for example, the resonant frequency in the direction perpendicular to the axis is 40Hz, and the resonant frequency in the axial direction is 40Hz.
Dynamic dampers respectively set at 80Hz can advantageously be provided.

Therefore, in the case of a dynamic damper with such a structure, the frequency to be reduced may be applied to a rotating shaft where the frequency in the axial direction is greater than the frequency in the direction perpendicular to the axis. It can be used successfully and a very effective damping effect for vibrations in both directions can be found in one damper.

Furthermore, in the dynamic damper of this embodiment, the cylindrical portion 14 is connected to the damper mass 24.
Temporary excessive vibrations are input to the rotating shaft 12 because the rotating shaft 12 is formed to extend a predetermined length in the axial direction, so that it also exists on the radially inner side of the part where the rotating shaft 12 is disposed. The damper mass 24
Even when an excessive displacement is caused, the excessive displacement of the damper mass 24 can be regulated, and the impact of the damper mass 24 against the rotating shaft 12 can be buffered, thereby preventing damage to the damper and the rotating shaft. It can be effectively prevented.

FIG. 3 shows another embodiment constructed according to the present invention.

In the drawings, members having the same structure as those in the embodiment described above are designated by the same numbers as the corresponding members, and detailed explanations thereof will be omitted.

That is, as is clear from FIG. 3, the dynamic damper in this embodiment has a cylindrical portion 14 having a cylindrical shape and an elastic support portion 18 having an L-shaped cross section. The elastic body of the damper body has a structure substantially similar to that of the embodiment described above, in which a ring-shaped damper mass 24 is integrally disposed on the free end side portion of the axial portion 22 of the support portion 18. 10 cylindrical parts 1
A metal sleeve 26, which is longer than the cylindrical portion 14 by a predetermined dimension, is fixed to the inner peripheral surface of the cylindrical portion 4.

The dynamic damper having such a structure can effectively achieve various effects similar to those of the damper in the embodiment described above, and the metal sleeve 26 can be mounted on a predetermined rotating shaft 12. Since this can be done by press-fitting, there is no need to provide a tightening band or the like, and the structure of such a damper can be further simplified, and its manufacture and installation can be performed more easily.

Although two embodiments having a structure according to the present invention have been described in detail above, these are literal illustrations, and the present invention should not be interpreted as being limited to such specific examples.

For example, in the dynamic damper in the embodiment described above, the cylindrical portion 14 was formed to extend a predetermined length toward the damper mass 24 so that the cylindrical portion 14 was also present on the radially inner side of the damper mass 24. The extending portion of the cylindrical portion 14 is not necessarily required. Furthermore, without forming the cylindrical portion 14 to extend toward the side where the damper mass 24 is disposed, the elastic convex portions protruding radially inward in the portion located on the radially inner side of the damper mass 24 extend in the circumferential direction. A similar effect can be achieved by forming a structure continuously.

In addition, the weight of the damper mass 24, the member thickness, member length, material, etc. of the radial portion 20 and the axial portion 22 in the dynamic damper according to the present invention are determined by the resonance in the axial direction and the axis-perpendicular direction of the dynamic damper. The frequency is changed and set as appropriate in order to tune the frequency to the frequency of vibration in the axial direction and the direction perpendicular to the axis, which are aimed at reduction on the rotating shaft to which the damper is attached, and is not limited to the above. . By adjusting these, the dynamic damper according to the present invention can be used to reduce the frequency of vibrations in the axial direction and the frequency in the direction perpendicular to the axis, which are aimed at reducing vibrations in the direction perpendicular to the axis. Of course, it can be used favorably for a rotating shaft whose axial frequency is smaller than the number of vibrations, and can exhibit an excellent vibration absorption effect.

Although not listed in detail, the present invention may be implemented with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and such embodiments may be implemented in accordance with the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not deviate from the spirit.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a dynamic damper as an embodiment of the present invention, FIG. 2 is a front view of the dynamic damper shown in FIG. 1, and FIG. FIG. 2 is a longitudinal sectional view corresponding to FIG. 1 showing another embodiment of such a dynamic damper. 10: Elastic body, 12: Rotating shaft, 14: Cylindrical part,
18: elastic support part, 20: radial part, 22: axial part, 24: damper mass.

Claims (1)

[Scope of utility model registration request] For an elastic body having a cylindrical part attached directly or indirectly to a predetermined rotating shaft, a radial part extending radially outward for a predetermined length from the outer peripheral surface of the elastic body and an end of the radial part An L-shaped elastic support part consisting of an axial part extending a predetermined length in the axial direction is integrally provided, and a damper mass of a predetermined weight is attached to the free end side of the axial part of the elastic support part. A dynamic damper characterized by being integrated.