JP7329372B2 - dynamic damper - Google Patents

Description

The present invention relates to dynamic dampers.

2. Description of the Related Art In automobiles, particularly four-wheel drive vehicles, it is known that drive system vibration induces vehicle body vibration and vehicle interior noise, and a dynamic damper (dynamic vibration absorber) is used as one of the countermeasures.

A dynamic damper used in a propeller shaft for a vehicle is generally a combination of a mounting ring (outer pipe), a mass (damper mass), and an elastic body made of a rubber-like elastic material connecting them. It contributes to quietness during running by exhibiting the dynamic vibration absorber effect.

Japanese Patent Application Laid-Open No. 2003-240052

However, in the above dynamic damper, the mass is largely eccentric during rotation, so that unbalanced vibration increases in the high-speed rotation range, which may worsen vehicle body vibration and vehicle interior noise.

As shown in FIG. 4, in order to suppress the unbalanced vibration in the high-speed rotation range, a plurality of elastic bodies 52 (in the drawing, equally spaced at 5) are arranged on the inner peripheral side of the mounting ring 51 on the circumference. In some cases, a convex shape 54 made of a rubber-like elastic material is provided as a stopper for the purpose of suppressing the eccentricity of the mass 53 between them.

According to this countermeasure, when an excessive load due to centrifugal force acts on the unbalanced mass 53, the mass 53 contacts the convex shape 54, so that the eccentricity of the mass 53 can be suppressed. .

However, according to this measure, the initial radial clearance c set between the mass 53 and the convex shape 54 is formed by a rubber molding die (not shown) for molding the elastic body 52 and the convex shape 54. Therefore, considering the maintenance of the rubber molding die, the minimum value of the radial clearance c is about 1 mm. Therefore, the radial clearance c cannot be set any smaller, and the eccentricity of the mass 53 cannot be suppressed any smaller. If the radial clearance c is 1 mm, the rotational imbalance of the propeller shaft due to the eccentricity of the mass 53 may become a problem depending on the vehicle. balance).

Further, since the convex shape 54 as the eccentric stopper is made of a rubber material, the convex shape 54 is compressed and deformed even after the stopper is actuated, allowing the eccentricity of the mass 53 to some extent. Therefore, the function as an eccentric stopper may be insufficient.

To provide a dynamic damper mounted inside a hollow shaft, capable of suppressing the eccentricity of a mass and further suppressing the eccentricity of a mass by providing a high-rigidity eccentric stopper. and Another object of the present invention is to provide a dynamic damper capable of exerting the eccentric stopper function only by the damper component parts without depending on parts other than the damper such as the propeller shaft.

One aspect of the dynamic damper is a mounting ring disposed inside a hollow shaft and fixed to the hollow shaft; a body, a mass connected to the elastic body at one axial position, and a metal mounting ring extension provided on the inner peripheral side of the elastic body from the mounting ring toward the mass. the mounting ring extension has a guide portion on its distal end outer peripheral surface; the mass has a guided portion corresponding to the guide portion; and the guide portion and the guided portion are each tapered. It was formed in a planar shape, an initial clearance in the axial direction was set between the guide portion and the guided portion, and during rotation, the elastic body expanded due to centrifugal force and elastically deformed so as to reduce its axial length. When the mass is axially displaced in a direction approaching the mounting ring extension portion, the mass is eccentric and the guided portion comes into contact with the guide portion, thereby suppressing the eccentricity of the mass .

In a dynamic damper mounted inside a hollow shaft, the eccentricity of the mass can be suppressed to a small level, and a dynamic damper capable of suppressing the eccentricity of the mass by providing an eccentric stopper with high rigidity can be provided. . In addition, it is possible to provide a dynamic damper capable of exhibiting the eccentric stopper function only with the damper component parts, without depending on parts other than the damper such as the propeller shaft for the eccentric stopper function.

Sectional view of the dynamic damper according to the embodiment (A) is a partially enlarged view of FIG. 1, and (B) is a partially enlarged view showing the same operating state. Sectional view of a dynamic damper according to another embodiment Cross-sectional view of the dynamic damper described in Background Art

As shown in FIG. 1, the dynamic damper 1 according to the embodiment is a dynamic damper mounted inside a hollow shaft 61 such as a propeller shaft for a vehicle, and dampens vibrations generated in the hollow shaft 61 during rotation. In addition to improving quietness during running, it also prevents a decrease in strength due to resonance of the hollow shaft 61 itself.

The dynamic damper 1 includes a mounting ring 11 which is disposed inside the hollow shaft 61 and is fitted and fixed to the inner peripheral surface of the hollow shaft 61, and which is biased to one axial position (left side in the drawing) with respect to the mounting ring 11. and a mass 31 connected to the elastic body 21 at one axial position. A mounting ring extension 41 made of a rigid material such as metal is provided from the ring 11 toward the mass 31 . The mass 31 functions as an inertial mass in the damper resonance system, and the elastic body 21 functions as a spring. In addition, since the elastic body 21 is deformed by shearing rather than by compression with respect to an input in the direction perpendicular to the axis, it can easily cope with low-frequency vibrations in the direction perpendicular to the axis.

The mounting ring 11 is formed as a cylindrical sleeve from a rigid material such as metal.

The mass 31 is formed of a rigid material such as metal as a disk having a predetermined mass, and has an outer diameter smaller than the inner diameter of the hollow shaft 61 to provide a radial clearance between the mass 31 and the hollow shaft 61 . set. Therefore, the mass 31 does not come into contact with the hollow shaft 61 even if it is eccentric. Further, since the mass 31 is connected to the mounting ring 11 via the elastic body 21 at one axial position, the mass 31 is held by the mounting ring 11 and the elastic body 21 in a cantilever manner. A through hole 32 is provided in the center of the mass 31 for circulating a cleaning liquid or the like.

The elastic body 21 is formed in an annular shape from a rubber-like elastic material, is arranged between the mass 31 and the mounting ring 11, and is bonded (vulcanized) to the mass 31 at one end in the axial direction. The mounting ring 11 and the mass 31 are connected as described above by bonding (vulcanization bonding) to the mounting ring 11 at the end on the opposite side (right side in the drawing).

An outer peripheral rubber portion 22 integral with an elastic body 21 is provided on the outer peripheral side of the mounting ring 11 . The outer peripheral rubber portion 22 is annularly formed of a rubber-like elastic material, formed integrally with the elastic body 21 , and adhered (vulcanized) to the outer peripheral surface of the mounting ring 11 . is formed large, it is interposed between the mounting ring 11 and the hollow shaft 61 with a radial interference.

An inner peripheral rubber portion 23 integral with the elastic body 21 is provided on the inner peripheral side of the mounting ring 11 . The inner peripheral rubber portion 23 is annularly formed of a rubber-like elastic material, formed integrally with the elastic body 21 and the outer peripheral rubber portion 22 , and bonded (vulcanized) to the inner peripheral surface of the mounting ring 11 .

A mass covering portion 24 integral with the elastic body 21 is provided on the outer peripheral side of the mass 31 . The mass covering portion 24 is made of a rubber-like elastic material and formed in the shape of an annular thin film. The outer peripheral surface is covered over the entire circumference and the entire surface. Since the mass covering portion 24 is formed as a thin film, it does not affect the setting of the radial clearance.

The attachment ring extension part 41 is formed as a cylindrical sleeve component from a rigid material such as metal, and has a tip end peripheral surface for suppressing the eccentricity of the mass 31 and for aligning the mass 31 on the damper center axis. An annular guide portion 46 is provided.

Further, the attachment ring extension portion 41 includes an annular attachment portion 42 fitted and fixed to the inner peripheral side of the attachment ring 11 , and an annular extension portion 42 extending radially inward from one axial end of the attachment portion 42 . A stepped end surface portion 43 is provided, and an annular extension portion main body 44 is provided from the inner peripheral end portion of the end surface portion 43 toward one axial direction. An annular tapered bent portion 45 is provided radially inward, and the outer peripheral surface of the bent portion 45 serves as the guide portion 46 having an annular tapered surface.

The mounting portion 42 is fitted and fixed to the inner peripheral surface of the mounting ring 11 via the inner peripheral rubber portion 23 . The extension main body 44 has a radial clearance with the elastic body 21 so as not to hinder the elastic deformation of the elastic body 21 and is not in contact with the elastic body 21 .

In addition, a guided portion 34 is provided on the mass 31 corresponding to the bent portion 45 and the guide portion 46, that is, a concave portion 33 is provided on the end surface of the mass 31 on the opposite side in the axial direction. A guided portion 34 having an annular tapered surface is formed.

The guide portion 46 is arranged on the inner peripheral side of the guided portion 34 , and the guided portion 34 is arranged on the outer peripheral side of the guide portion 46 .

An initial axial clearance is set between the guide portion 46 and the guided portion 34 , and an initial radial clearance is accordingly set between the guide portion 46 and the guided portion 34 . Therefore, the guide portion 46 and the guided portion 34 are not in contact with each other in the initial state. The radial clearance is set to a size of less than 1 mm, for example.

Further, in this manner, the guide portion 46 and the guided portion 34 are not in contact with each other in the initial state, but are arranged so as to partially overlap each other in the axial direction. Therefore, in the initial state shown in FIG. 2A, when the mass 31 is eccentric and radially displaced in the direction of the arrow _H1 , the guided portion 34 comes into contact with the guide portion 46, thereby restricting the radial displacement of the mass 31. Eccentricity of the mass 31 is suppressed.

In addition, in order to achieve the eccentricity suppressing function of the mass 31 by the guide portion 46, the initial clearance in the radial direction set between the guide portion 46 and the guided portion 34 is equal to the diameter set between the mass 31 and the hollow shaft 61. It is set smaller than the directional clearance.

In the dynamic damper 1 configured as described above, the mounting ring 11 is provided with the mounting ring extension portion 41, and the tip of the mounting ring extension portion 41 is provided with the guide portion 46. A portion to be guided 34 is provided by the inner peripheral surface of the recess 33, and an initial radial clearance is set between the guide portion 46 and the portion to be guided 34. This clearance is set small, and in the above example, the size is less than 1 mm. Therefore, the amount of eccentricity of the mass 32 can be kept small compared to the reference example shown in FIG. Therefore, the eccentricity of the mass 31 does not become excessive, and the problem of rotational imbalance of the propeller shaft caused by the eccentricity of the mass 31 can be suppressed.

Further, since the eccentric stopper is a combination of the attachment ring extension 41 and the mass 31, that is, a combination of metal parts, the mass 31 is hardly eccentric after the eccentric stopper is actuated. Therefore, it is possible to form an eccentric stopper having higher rigidity than the reference example shown in FIG.

Further, when the propeller shaft rotates at high speed and the damper 1 rotates at high speed accordingly, the axial central portion of the elastic body 21 is directed radially outward due to the centrifugal force as shown in FIG. 2(B). Inflating (arrow H ₂ ), the elastic body 21 is elastically deformed to reduce its axial length. When the elastic body 21 is elastically deformed in this manner, the mass 31 is displaced in the axial direction (arrow H ₃ ) toward the mounting ring extension portion 41 , and at this time the mass 31 contacts the guide portion 46 at the guided portion 34 . As a result, the center axis of the damper 1 is aligned. Therefore, the eccentricity of the mass 31 can also be suppressed by this.

As shown in FIG. 3, by embedding a plurality of weight members 47 on the circumference within the thickness of the annular elastic body 21, the weight members 47 expand due to centrifugal force even in a relatively low propeller shaft rotation speed range. As a result, the mass 31 moves in the axial direction and comes into contact with the stopper (the guide portion 46), so that radial displacement of the mass 31 can be suppressed.

Further, in the above configuration, the eccentric stopper does not depend on parts other than the damper 1, such as the propeller shaft, and can exhibit the eccentric stopper function only with the components of the damper 1 (mounting ring extension 41 and mass 31). It is Therefore, it is possible to form an eccentric stopper that operates with high accuracy without being affected by the dimensions of a propeller shaft or the like manufactured by the user.

The configuration of the dynamic damper 1 according to the above embodiment may be added or modified as follows.

The mounting ring extension part 41 is integrally formed with the mounting ring 11 rather than separately. In this case, the part to be integrated is provided with, for example, an annular stepped end surface portion 43 directed radially inward from one end portion in the axial direction of the portion corresponding to the mounting ring 11 , and an inner peripheral end portion of the end surface portion 43 . An annular extension main body 44 is provided toward one axial direction from the extension main body 44, and an annular tapered bent portion 45 extending radially inward from one axial end of the extension main body 44 in the axial direction. is provided, and the outer peripheral surface of this bent portion 45 serves as a guide portion 46 exhibiting an annular tapered surface shape.

Reference Signs List 1 dynamic damper 11 mounting ring 21 elastic body 22 outer peripheral rubber portion 23 inner peripheral rubber portion 24 mass covering portion 31 mass 32 through hole 33 concave portion 34 guided portion 41 mounting ring extension portion 42 mounting portion 43 end surface portion 44 extension portion 45 bending portion 46 guide portion 47 weight member 61 hollow shaft

Claims (2)

a mounting ring disposed inside the hollow shaft and fixed to the hollow shaft;
an elastic body made of a rubber-like elastic material and connected to the mounting ring at one axial position;
a mass coupled to the elastic body at one axial position;
a metal mounting ring extension provided from the mounting ring toward the mass on the inner peripheral side of the elastic body;
with
The mounting ring extension has a guide portion on its outer peripheral surface,
The mass includes a guided portion corresponding to the guide portion,
The guide portion and the guided portion are each formed in a tapered surface,
An initial axial clearance is set between the guiding portion and the guided portion,
During rotation, when the elastic body swells due to centrifugal force and is elastically deformed to reduce its axial length, the mass is displaced in the axial direction toward the extension of the mounting ring, and at this time the mass is eccentric . suppressing the eccentricity of the mass by contacting the guided portion with the guide portion ;
A dynamic damper characterized by: The dynamic damper according to claim 1 ,
A dynamic damper, wherein the mounting ring extension is formed by a sleeve-like part fixed to the mounting ring.

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