JP2002235836A - Vibration damping gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with a mounting means of a vibration damper and mount the vibration damper without constraint on a mounting position in a gear for damping the vibration by frictional force. SOLUTION: This vibration damping gear is composed of a gear body 1, and vibration dampers 2A, 2B mounted on the gear body 1. The vibration damper is made of a circular member engaged with the gear body and free from a cut in the circumferential direction, and fixed on the gear body by the friction bonding of a fitting part Z by press fitting, shrinkage fitting, hardening strain after fitting or the like, and the vibration produced by the fitting is absorbed by the friction between the gear body and a joint part of the vibration damper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear used for various transmissions, and more particularly, to a vibration damping structure for vibration generated by meshing the gears.

[0002]

2. Description of the Related Art Since gears transmit power through meshing of tooth surfaces, it is difficult to avoid a certain degree of vibration due to meshing pitch errors. Such vibrations are transmitted to the case of the transmission device via the gear shaft and its supporting bearings, and are felt as gear noise by the vibration of the case.
In order to suppress this, various vibration suppression measures have been conventionally proposed. Among such measures, as a highly effective vibration suppression measure, there is a method of converting vibration energy into friction energy and absorbing it. An example of a structure using this method is disclosed in Japanese Utility Model Laid-Open No. 7-12653. In this structure, a configuration is adopted in which a vibration damper (ring-shaped main body portion) that engages in an annular engagement groove formed in a plate surface of the gear main body is frictionally tightened to the gear main body by a tightening means. . According to this structure, the plate surface of the vibration damper and the bottom surface of the annular engagement groove of the gear body come into surface contact with each other, so that the vibration can be suppressed by the frictional force generated between the members.

[0003]

However, in the above-mentioned conventional structure, a separate member fastening means (specifically, a rivet) is used for attaching the vibration damper (ring-shaped main body) to the gear main body. Not only the structure becomes complicated, but also processing of rivet through holes in the gear body and the vibration damper, and processing such as rivet tightening are required.

Accordingly, the present invention has as its main object to provide a vibration-damping structure that does not require any additional members for mounting the vibration-damping member on the gear body in a gear that performs vibration damping by the above-described frictional force. Aim. Next, it is a further object of the present invention to provide a vibration damping structure that eliminates restrictions on the mounting position of the vibration damping body.

[0005]

An object of the present invention is to provide a vibration damping gear comprising a gear main body and a vibration damping body attached to the gear main body, wherein the vibration damping body has a circumferential direction fitted to the gear main body. This is achieved by a configuration in which the ring member is a continuous annular member and is fixed to the gear body by frictional joining of the fitting portions.

[0006] The frictional joining may be established by interference fit of the vibration damper to the gear body.

[0007] The frictional joining may be established by shrink fitting of the vibration damper to the gear body.

Alternatively, the frictional joining may be established by quenching distortion after fitting of the vibration damper to the gear body.

It is effective that the fitting portion is located on the outer diameter side when the gear body is viewed in the radial direction.

Specifically, the fitting portion is constituted by a gear body and a circumferential surface of the vibration damper.

The circumferential surface may be constituted by a circumferential surface of a groove formed in the gear body and a circumferential surface of the vibration damper.

Alternatively, the circumferential surface may be constituted by an inner circumferential surface of an outer diameter side boss of the gear body and an outer circumferential surface of the vibration damper.

Alternatively, the circumferential surface may be constituted by an outer peripheral surface on the outer diameter side of the gear body and an inner peripheral surface of the vibration damper.

[0014]

According to the structure of the first aspect of the present invention, the frictional joint between the gear body and the vibration damper functions as a friction generating part and also functions as a fastening part. A fastening member for attaching to the vibration damper is not required. As a result, simplification of the structure of the damping gear and reduction in the number of processing steps are achieved. Further, since a support portion of the fastening member and a space for fastening processing are not required, restrictions on the arrangement position of the vibration damper can be eliminated.

According to the second aspect of the present invention, the damping member can be assembled for fixing the damper at an appropriate time during the gear machining process. Even after the heat treatment performed on the gear, the vibration damper can be fitted without affecting the accuracy of the gear.

Further, according to the configuration of the third aspect, the work of fitting the vibration damping member using the heat treatment step of the gear can be performed.

Further, according to the configuration of the fourth aspect, the fitting of the vibration damping body to the gear body can be performed by the gap fitting, so that the assembling work is facilitated.

Next, according to the structure of the fifth aspect, since the circumferential length of the fitting portion is long, it is easy to secure a wide friction surface, which is advantageous for improving the vibration damping effect.

Further, according to the structure of the sixth aspect, it is not necessary to perform special processing for fixing the vibration damper to the gear body, so that the number of processing steps of the gear is reduced.

Further, according to the structure of the seventh aspect, the vibration damping gear can be constituted by incorporating the vibration damping member into the gear main body without substantially changing the gear shape. In addition, since the inside of the orbital groove is filled by the damping body without substantial gap,
The rigidity of the gear is also sufficiently ensured.

Further, according to the configuration of the eighth aspect, the vibration damping member can be fixed to the gear body without forming a groove in the gear body. In addition, the securing that maximizes the circumferential length of the fitting portion facilitates securing the friction area.

Further, according to the structure of the ninth aspect, it is possible to realize a vibration damping structure of a ring gear which cannot be realized because the conventional structure having a radial surface as a friction surface requires a radial width. Can be.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. First, FIG.
1 shows a cross-sectional structure of a vibration damping gear according to a first embodiment in half. This gear has a gear body 1 having outer peripheral meshing teeth 10.
And a pair of vibration dampers 2A, 2B attached to the gear body 1.
It is composed of These damping bodies 2A and 2B are annular members which are fitted in the gear body 1 and have no break in the circumferential direction (hereinafter referred to as damping rings in the description of the embodiment).
And is fixed to the gear body 1 by frictional joining of the fitting portion Z.

More specifically, the gear body 1 in this embodiment
Has a rim portion 12 extending in the axial direction on the outermost diameter side of the radial flange portion 11, and is an externally meshed gear having a tooth profile formed on an outer peripheral surface thereof. And in the gear body 1,
The inner diameter of the rim portion 12 is defined as the outer diameter, and both vibration damping rings 2A,
A pair of back-to-back circumferential grooves 13, 14 having a width substantially corresponding to the radial thickness of 2B are formed at a predetermined axial depth. The vibration damping rings 2A and 2B fitted in these grooves 13 and 14 substantially correspond to the rim portion 1 of the gear body 1.
The outer diameter corresponding to the inner diameter of No. 2 is larger than the thickness in the radial direction (difference between inner and outer diameters), and the axial width is larger than the axial depth of each of the circumferential grooves 13 and 14. It has a hollow cylindrical shape. Thus, in this embodiment, the fitting portion Z is constituted by the inner and outer peripheral surfaces of the both circumferential grooves 13 and 14 formed in the gear main body 1 and the inner and outer peripheral surfaces of both the vibration damping rings 2A and 2B. Are located on the outer diameter side when viewed in the radial direction. In addition, in the following description of the embodiment, the alphabetical addition symbols A and B of the vibration damping ring 2 that adopts this arrangement position (including other additional symbols in the following embodiments).
Represents the shape at the same time as their disposition positions.

Both circumferential grooves 1 of these vibration damping rings 2A, 2B
The fastening to the members 3 and 14 can take various forms according to the processing convenience. For example, when the vibration damping rings 2A, 2B are fitted after heat treatment such as carburizing and quenching of the gear body 1, the inner and outer diameters of the vibration damping rings 2A, 2B are determined by the circumferential grooves 13, 14 of the gear body 1 after the processing. The inner and outer diameters are set to be slightly larger than the inner and outer diameters, so that the interference fit is established by press-fitting. When the heat treatment of the gear body 1 is performed after the damping rings 2A, 2B are fitted, the inner and outer diameters of the damping rings 2A, 2B are set to the grooves 13, 14 of the gear body 1.
The inner and outer diameters are set to be slightly smaller than the inner diameter to facilitate the insertion, and the interference fit is established by quenching distortion. Alternatively, an interference fit state can be established by shrink fitting in an appropriate step regardless of these processing procedures. In any case, the damping ring 2A,
2B is fixed to the circumferential grooves 13 and 14 in the vibration load state at the time of power transmission meshing, and the gear body 1
What is necessary is just to generate mutual friction between the vibration damping rings 2A and 2B. If there is a concern that the vibration damping rings 2A, 2B may come off under this vibration load state, it is sufficient to prevent the vibration damping rings 2A, 2B from coming off by local caulking.

Next, FIG. 2 shows a cross-sectional structure of a vibration damping gear according to a second embodiment in half. The gear body 1 in this embodiment is the same as that of the first embodiment, and the arrangement position of the vibration damping ring 2 is different. In this case, the gear body 1 is provided on its flange portion 11 with the respective vibration damping rings 2C, 2D.
The circumferential grooves 15 and 16 having appropriate widths substantially corresponding to the radial thicknesses are formed at predetermined axial depths, displaced in the radial direction, and opposite to each other. 15,
The two damping rings 2C and 2D are fixed to 16. In the case of this form, since the arrangement position is the flange portion 11, the depth of each groove 15, 16 and the vibration damping rings 2C, 2D are set in order to prevent the both vibration damping rings 2C, 2D from protruding in the axial direction.
Have the same axial width. Other configurations are the same as those in the first embodiment in terms of quality, and therefore, description thereof is omitted.

Next, a third embodiment shown in FIG. 3 is a combination of the two embodiments. In other words, this damping gear has a configuration in which all of the orbiting grooves 13 to 16 are formed in the gear body 1 and all four damping rings 2A to 2D are fixed thereto.

The following three forms shown in FIG. 4 show modifications of the third embodiment. The modification shown in FIG. 4A shows the orbital groove 13 and the vibration damping ring 2A of the third embodiment. It is a thing which lost. Further, the modification shown in FIG.
In this modification, the orbital groove 16 and the vibration damping ring 2D are further eliminated from the modification shown in FIG. Further, the modification shown in FIG. 7C is obtained by further removing the orbital groove 15 and the vibration damping ring 2C from the modification of FIG.

The following two embodiments shown in FIG. 5 show the fourth embodiment and its modifications. In the fourth embodiment shown in FIG. 7A, the arrangement position of the vibration damping ring is similar to that of the first embodiment, but the fitting relationship is similar to that of the second embodiment. In this case, the circumferential grooves on the side of the gear body 1 are the same as the circumferential grooves 13 and 14 having the same diameter as in the first embodiment, and the two vibration damping rings 2E and 2F fitted to these grooves project from the flange portion 11. As in the second embodiment, the setting is made in accordance with the depth of the circumferential grooves 13 and 14, in order to eliminate the problem. In the modification shown in FIG. 7B, the vibration damping ring 2F of the fourth embodiment is replaced with the vibration damping ring 2B of the first embodiment.

Next, the relationship between the arrangement of the vibration damping ring 2 and the vibration damping effect in each of the above embodiments will be described, including the selection of materials. FIG. 6 is a table showing control factors and their levels in an experiment conducted to verify the effect of each embodiment. In this experiment, for the base gear, the combination of damping ring arrangement, material (steel and cast iron) and heat treatment (dough and carburizing) was used as a control factor, and the presence / absence and type of these factors were set as a level. Then, the vibration damping abilities of various test gears were compared. From this experiment, those having particularly good vibration damping characteristics were selected and shown in a chart in FIG. By the way, No1 and No
2 are the ring arrangement of the third embodiment (FIG. 3).
No.3) with material and heat treatment changed
Gears of the ring arrangement of the third modification of the third embodiment (see FIG. 4 (C)), and gears No. 4 and No. 5 are ring arrangements of the modification of the fourth embodiment (FIG. 5 (B)). (See Reference)).

The above test yielded the results shown in FIG. The upper part of the figure shows the first of the test gears No1 to No5.
The damping ratio with respect to the natural frequency is shown in comparison with the base material without the damping ring. Similarly, the lower part of the figure shows the damping ratio with respect to the third natural frequency of the same test gear in comparison with the base material. Show. As a result of this experiment, it was verified that at least the damping ring is positioned on the outer diameter side when the gear body is viewed in the radial direction, and particularly, the damping ring provided on both sides has a large damping effect. In addition, no significant difference was observed depending on the difference in the material and the presence or absence of heat treatment.

FIG. 9 shows a model of the effect of the vibration damping ring from the results. As shown,
When the vibration generated from gear meshing is transmitted from the rim of the gear to the hub through the flange, the vibration energy is converted into friction energy by the relative friction of the mating surface with the vibration damping ring. As a result, the vibration transmitted to the hub portion is attenuated by being released as heat energy, and the gear noise is reduced due to a reduction in the vibration transmitted to the case and the like.

The fifth embodiment shown in FIG. 10 differs from the previous embodiment in that the circumferential groove of the fitting portion Z is provided without providing a circumferential groove on the side of the gear body 1 in order to further reduce the number of machining steps. The surface is composed of a circumferential surface 1a that is the inner circumferential surface of the outer diameter side rim portion 12 of the gear body 1 and a circumferential surface 2a that is the outer circumferential surface of the vibration damping rings 2G and 2H. In the case of this embodiment, the arrangement in which the two vibration damping rings 2G and 2H are located on the outer diameter side when the gear body 1 is viewed in the radial direction is followed.

Next, a sixth embodiment shown in FIG. 11 is obtained by changing the shape of the vibration damping ring 2 from the fifth embodiment. In this embodiment, the vibration damping rings 2I and 2J are thin ring-shaped rings whose radial dimension is larger than their axial dimension. In this case, it is difficult to use the fitting portion itself as the friction surface, but the vibration damping effect can be obtained in which the large radial surfaces that are in contact with each other by the fastening are used as the friction surfaces.

Finally, a seventh embodiment shown in FIG. 12 shows an example in which the present invention is applied to a ring gear. In this embodiment, since the gear body 1 has the meshing teeth 10 on the inner peripheral side,
A configuration is adopted in which the vibration damping ring 2K is fixed to the outer peripheral side of the gear body 1. Specifically, the outer peripheral surface of the gear body 1 is cut out by an amount corresponding to the axial width of the vibration damping ring 2 </ b> K, and the circumferential surface 1 a of the vibration damping ring 2 is fastened to the circumferential surface 1 a of the notch 19. Fitted and fastened. Also in the case of this embodiment, the arrangement in which the vibration damping ring 2K is located on the outer diameter side when the gear body 1 is viewed in the radial direction is followed, so that a friction surface as wide as possible is secured.

As described above, the present invention has been described in detail with reference to a number of embodiments. However, the exemplification of the embodiments is for understanding the invention, and various modifications based on the matters described in the claims are not limited to the embodiments. Is not intended to be excluded from the scope.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a circumscribed mesh vibration damping gear according to a first embodiment of the present invention.

FIG. 2 is a half sectional view of a circumscribed mesh vibration damping gear according to a second embodiment.

FIG. 3 is a half sectional view of a circumscribed mesh vibration damping gear according to a third embodiment.

FIG. 4 is a half-sectional view of a circumscribed mesh vibration damping gear according to a modification of the third embodiment.

FIG. 5 is a half sectional view of a circumscribed mesh vibration damping gear according to a fourth embodiment and a modification thereof.

FIG. 6 is a table showing control factors used for verifying the vibration damping effect of each embodiment.

FIG. 7 is a list of test gears used for verification.

FIG. 8 is a graph comparing the verification results with the attenuation ratio.

FIG. 9 is an operation explanatory view showing a model of a vibration damping effect of each embodiment.

FIG. 10 is a half sectional view of a circumscribed mesh vibration damping gear according to a fifth embodiment.

FIG. 11 is a half sectional view of a circumscribed mesh vibration damping gear according to a sixth embodiment.

FIG. 12 is a half sectional view of an internal meshing vibration damping gear according to a seventh embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gear main body 12 Rim part 13-16 Groove 2A-2K Damping ring (damping body) 1a, 2a Circumferential surface Z Fitting part

Claims (9)

[Claims] 1. A vibration damping gear comprising a gear body and a vibration damper attached to the gear body, wherein the vibration damper is a circumferentially continuous annular member fitted to the gear body, A vibration damping gear, which is fixed to a gear body by friction joining of a fitting portion. 2. The vibration damping gear according to claim 1, wherein the frictional connection is established by press-fitting the vibration damping body into the gear body. 3. The damping gear according to claim 1, wherein the frictional connection is established by shrink-fitting the damping body to the gear body. 4. The vibration damping gear according to claim 1, wherein the friction welding is established by quenching distortion after fitting of the vibration damping body to the gear body. 5. The vibration damping gear according to claim 1, wherein the fitting portion is located on an outer diameter side when the gear body is viewed in a radial direction. 6. The vibration damping gear according to claim 1, wherein the fitting portion includes a gear body and a circumferential surface of the vibration damper. 7. The vibration damping gear according to claim 5, wherein the circumferential surface is constituted by a peripheral surface of a groove formed in the gear body and a peripheral surface of the vibration damper. 8. The vibration damping gear according to claim 5, wherein the circumferential surface is constituted by an inner circumferential surface of an outer diameter rim portion of the gear body and an outer circumferential surface of the vibration damper. 9. The vibration damping gear according to claim 5, wherein the circumferential surface includes an outer peripheral surface on an outer diameter side of the gear body and an inner peripheral surface of the vibration damper.