JP2004125054A - Forging gear, method of manufacturing the same, and mould for forging gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a gear which eliminates warping in configuration of the gear induced from influence in manufacturing error and distortion of heat treatment and restrains the gear from occurring noise. <P>SOLUTION: The forging gear 1 is configured to form at least one of tooth thickness and pressure angle of basic tooth profile 2 by aligning tooth varying within gear required precision along with the basic tooth profile. The tooth thickness and the pressure angle of thinner tooth profile 3 and those of thicker tooth profile 4 relative to the basic tooth profile 2 are determined so as to become optimal increased and decreased amount at every tooth within the gear required precision. In addition, error of gear shape inducing to gear noise and assembled error of the gear are adjusted at every tooth and engagement due to every tooth is made to optimal condition. Alteration in the gear shape at every tooth of the forging gear 1 can perform by adjusting surface shape of product in forging mould concerned to manufacture of the forging gear. Once determining the shape of the mount, it is possible to inexpensively provide a majority of the gears which restrain the gear from occurring the noise. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for reducing gear noise.
[0002]
[Prior art]
There are various causes of the generation of the gear noise generated during the operation of the gear, and for example, each error of the accuracy, the tooth profile, the pressure angle, the pitch, and the eccentricity of the gear contributes to the cause. Therefore, conventionally, a design method for suppressing the error at the time of gear specification design has been devised (for example, see Patent Document 1).
Also, after heat treatment, by changing the gear pitch error discontinuously by grinding, the gear noise fluctuation caused by the load fluctuation during the gear operation is reduced, and the absolute value of the gear noise is also reduced, and the manufacturing of the gear. A method has been devised (for example, see Patent Document 2).
[0003]
[Patent Document 1]
JP-A-2002-122215 (Section 5, [0034], FIG. 8)
[Patent Document 2]
JP-A-7-35218 (page 2 [0007], FIG. 3)
[0004]
[Problems to be solved by the invention]
However, the gears based on the above prior art have the following problems. First, even when an ideal gear shape is designed by a design method for suppressing the error at the time of gear specification design, the completed gear is still affected by the processing error and heat treatment distortion at the time of actual manufacturing, and the completed gear is still Each error is provided. On the other hand, the technology for changing the pitch error discontinuously by grinding after heat treatment presupposes a gear manufacturing method using gear cutting (hob cutter), and a gear manufactured by such a manufacturing method can reduce large gear noise. However, it has been difficult to reduce small gear noise generated due to manufacturing errors. Therefore, it has been difficult for conventional gears to avoid secondary processing steps such as lapping in order to reduce gear noise to a required level.
The present invention has been made in view of the above-described problems, and an object thereof is to eliminate a gear shape disorder caused by a manufacturing error or an influence of a heat treatment distortion and to reduce the generation of gear noise at a low cost. To provide.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a forged gear according to claim 1 of the present invention is configured such that at least one of a tooth thickness and a pressure angle of a reference tooth profile is formed by arranging teeth in which a gear is appropriately changed within a range of required gear accuracy. It is a feature.
The gear obtained by this configuration has a different tooth shape for each tooth, and adjusts a gear shape error or a gear assembling error that causes gear noise for each tooth, and meshes each tooth. The gear noise can be reduced to an optimum state, and gear noise can be reduced. The change of the tooth shape for each tooth can be performed by adjusting the product surface shape of the forging die for manufacturing the forged gear.
In the present description, “reference tooth profile” means an ideal tooth profile determined based on a conventional tooth profile design procedure.
[0006]
In the forged gear according to the second aspect of the present invention, the forged gear according to the first aspect has an effect that a shape portion formed for the purpose of carrying a function other than the motion transmitting function of the gear affects heat treatment distortion of the gear. In consideration of the above, the change amount of at least one of the tooth thickness and the pressure angle is determined.
ADVANTAGE OF THE INVENTION According to this invention, it respond | corresponds to the heat processing distortion different for every shape of each gear appropriately, the gear shape error which causes gear noise, the gear assembly error, etc. are adjusted for every tooth, and the gear noise is reduced. Can be reduced.
[0007]
Further, the forged gear according to claim 3 of the present invention is the forged gear according to claim 1 or 2, in which at least one of the tooth thickness and the pressure angle is considered in consideration of the amount of eccentricity between the gear center and the rotation center. The amount of change is determined.
ADVANTAGE OF THE INVENTION According to this invention, by appropriately coping with the eccentricity of the gear center and the rotation center which is inevitable in manufacturing accuracy, by adjusting the tooth shape for each tooth, the meshing for each tooth is set in an optimal state. And gear noise can be reduced.
[0008]
According to a fourth aspect of the present invention, there is provided a method for manufacturing a forged gear according to the present invention, wherein a shape portion formed for the purpose of carrying a function other than the motion transmitting function of the gear gives heat treatment distortion of the gear. The present invention is characterized in that at least one of the tooth thickness and the pressure angle of each tooth is changed by utilizing the fact that polygonal deformation occurs in the gear due to the influence.
According to the present invention, the shape portion formed for the purpose of carrying a function other than the motion transmitting function of the gear influences the heat treatment distortion of the gear and utilizes the fact that the gear undergoes polygonal deformation, The gear noise can be reduced by adjusting at least one of the tooth thickness and the pressure angle of each tooth to adjust a gear assembly error or the like for each tooth.
[0009]
According to a fifth aspect of the present invention, there is provided a gear forging metal having a forming surface for forming the forged gear according to the first to fourth aspects.
Therefore, according to the gear forging die according to the present invention, by adjusting the tooth shape for each tooth, a gear with reduced gear noise can be manufactured by forging.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0011]
FIG. 1 shows an enlarged view of the teeth of a forged gear 1 according to an embodiment of the present invention. The forged gear 1 is formed by arranging teeth in which at least one of the tooth thickness and the pressure angle of the reference tooth profile 2 is changed within the range of the required gear accuracy together with the reference tooth profile. In FIG. From left to right, a reference tooth profile 2, a fine tooth profile 3 with a reduced tooth thickness, and a thick tooth profile 4 with an increased tooth thickness are shown side by side. Further, in the fine tooth profile 3 and the thick tooth profile 4, the tooth shape of the reference tooth profile 2 is illustrated by being superimposed with a thin line in order to clarify the shape difference from the reference tooth profile 2.
Actually, the reference tooth profile 2, the fine tooth profile 3, and the thick tooth profile 4 are arranged as necessary, and the tooth thickness and pressure angle of the fine tooth profile 3, the thick tooth profile 4 with respect to the reference tooth profile 2 are expressed by a gear. Within the range of the required accuracy, it is determined so that the amount of increase / decrease is optimal for each tooth. Further, there is a case where the forged gear 1 is composed of the fine tooth profile 3 and / or the thick tooth profile 4 without the reference tooth profile 2.
[0012]
FIG. 2 shows a case where a lightening hole 5 is formed on the forged gear 1 as a shape portion formed for the purpose of carrying a function other than the motion transmitting function. The lightening hole 5 is provided in the disk 8 connecting the center boss 6 and the tooth 7. In this case, the forged gear 1 undergoes polygonal deformation as shown by the outline 9 in FIG. 2A under the influence of the heat treatment distortion caused by the provision of the lightening hole 5. . This polygonal deformation is that the portion indicated by the arrow 10 in FIG. 2A is cooled faster than the other portion of the forged gear 1 due to the provision of the lightening hole 5, and the generated strain increases. It is caused.
[0013]
Although this polygonal deformation also affects the tooth profile aligned with the tooth portion 7, in the embodiment of the present invention, in consideration of the effect on the heat treatment distortion of the gear, the tooth thickness and pressure angle of each tooth are considered. At least one change amount is determined. Specifically, as shown in FIG. 3, the teeth located in the range 11 where the amount of contraction increases due to the provision of the lightening hole 5 are formed into the thick tooth shape 4, and the teeth located in the other range 12 are formed. Is forged as the reference tooth profile 2.
Further, in the embodiment of the present invention, shown in FIG. 4, in consideration of the eccentricity of the center C _T of forged gear 1 and the rotation center C _R, at least one of the change of the tooth thickness and pressure angles of each tooth The amount may be determined.
[0014]
The operation and effect obtained by the embodiment of the present invention having the above configuration are as follows. First, in the embodiment of the present invention, as shown in FIG. 1, the forged gear 1 is configured by changing the tooth shape for each tooth, and a gear shape error that causes gear noise, The gear assembly error and the like are adjusted for each tooth, so that the meshing for each tooth can be optimized. Gear noise can be reduced. The change of the tooth shape for each tooth of the forged gear 1 can be performed by adjusting the product surface shape of the forging die for manufacturing the forged gear, and once the die shape is determined, It is possible to provide a large number of gears with reduced generation of gear noise at low cost.
[0015]
In addition, in consideration of the effect of the lightening hole 5 on the heat treatment distortion of the forged gear 1, the amount of change in at least one of the tooth thickness and the pressure angle of each tooth is determined. By properly coping with the distortion, a gear shape error or a gear assembling error that causes gear noise can be adjusted for each tooth to reduce gear noise. The lightening hole 5 is shown as an example of a shape portion formed for the purpose of carrying a function other than the motion transmitting function of the gear, and other structural portions (for example, protrusions for positioning with other components) ) Can provide the same effect.
[0016]
In addition, it is also possible to positively use the polygon deformation. That is, the shape, size, number of installations, and installation intervals (equal pitch or unequal pitch) of the lightening holes 5 are arbitrarily determined, and the forged gear 1 is changed to a desired polygonal shape, and the polygonal deformation is utilized. It is also possible to intentionally change at least one of the tooth thickness and the pressure angle for each tooth.
Further, in consideration of the eccentricity of the gear center C _T and the rotation center C _R, by determining at least one of the change amount of the tooth thickness and pressure angles of each tooth, gear center C is on the manufacturing accuracy inevitably appropriate response to the eccentricity of the _T and the rotation center C _R, and adjust the tooth form for each one cog, it is possible to reduce gear noise.
[0017]
By adjusting the product surface shape of a forging die for manufacturing the forged gear 1 based on the shape of each tooth determined as described above, a large number of gears with reduced gear noise can be provided at low cost. Becomes possible.
[0018]
【The invention's effect】
Since the present invention is configured in this way, it is possible to provide a gear at a low cost, which eliminates gear shape irregularities due to the effects of manufacturing errors and heat treatment distortion and suppresses the generation of gear noise.
[Brief description of the drawings]
FIG. 1 is an enlarged view of a tooth of a forged gear according to an embodiment of the present invention.
2A and 2B show a forged gear provided with a lightening hole according to an embodiment of the present invention, wherein FIG. 2A is a side view and FIG. 2B is a cross-sectional view thereof.
FIG. 3 is an enlarged view of teeth of a forging die shown in FIG. 2;
4A and 4B show a forged gear in which the center of rotation and the center of rotation according to the embodiment of the present invention are eccentric, wherein FIG. 4A is a side view and FIG. 4B is a cross-sectional view thereof. .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Forged gear 2 Reference tooth form 3 Fine tooth form 4 Thick tooth form 5 Lightening hole 6 Center boss part 7 Tooth part 8 Disk part 9 Contour line

Claims (5)

A forged gear characterized in that at least one of a tooth thickness and a pressure angle of a reference tooth profile is formed by arranging teeth whose values are appropriately changed within a range of gear required accuracy. The shape part formed for the purpose of carrying a function other than the movement transmitting function of the gear, in consideration of the influence on the heat treatment distortion of the gear, is determined at least one of the change amount of the tooth thickness and the pressure angle. The forged gear according to claim 1, wherein The forged gear according to claim 1 or 2, wherein the amount of change of at least one of the tooth thickness and the pressure angle is determined in consideration of the amount of eccentricity between the center of the gear and the center of rotation. The shape thickness formed for the purpose of carrying a function other than the motion transmitting function of the gear, which affects the heat treatment distortion of the gear, causes the gear to undergo polygonal deformation. A method for manufacturing a forged gear, wherein at least one of the corners is changed. A gear forging die having a forming surface for forming the forged gear according to claim 1.

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