JP2010159835A - Ring gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress periodical noise and vibration when transmitting torque. <P>SOLUTION: A ring gear 1 includes a plurality of gear teeth 7 in a peripheral direction and transmits the torque by engaging the gear teeth with the gear tooth of a counter gear. A plurality of lightening parts 9d are provided in the peripheral direction on the back surface sides of the gear teeth 7, and the shapes of the plurality of lightening parts 9d are non-uniform. The shapes of the lightening parts 9d are different in at least one of a shape in a planar view and a cross-sectional shape. The lightening parts 9d are provided with respect to each predetermined pitch in the peripheral direction. Therefore, it is possible to non-uniformly perform heat-treatment deformation in the peripheral direction and to suppress the periodical noise and vibration when transmitting the torque. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ring gear used for a hypoid gear or the like.

  As a conventional ring gear, there exists a thing as shown to patent document 1, for example. The ring gear is manufactured through heat treatment and includes a plurality of gear teeth in the circumferential direction. This ring gear is used for a hypoid gear such as a final gear of a vehicle, for example, and the gear teeth mesh with the other gear teeth such as a pinion gear to transmit rotational force.

  The back side of the gear teeth is provided with a plurality of lightening portions in the circumferential direction to reduce weight. The plurality of thinned portions are formed at a predetermined pitch in the circumferential direction and are formed in a uniform shape. As a result, the ring gear is suppressed from variation in the amount of heat treatment deformation, thereby reducing noise and vibration.

  However, in the conventional structure, a cyclic heat treatment deformation is generated in the ring gear, and a periodic sound and vibration are generated when the rotational force is transmitted.

Japanese Patent Laid-Open No. Sho 62-127567

  The problem to be solved is that periodic sounds and vibrations are generated when torque is transmitted.

  The present invention is a ring gear that has a plurality of gear teeth in the circumferential direction and meshes with the gear teeth of the other party to transmit the rotational force in order to suppress periodic sound and vibration during torque transmission. The most main feature is that a plurality of lightening portions are provided in the circumferential direction on the back side of the teeth, and the shapes of the plurality of lightening portions are non-uniform.

  The ring gear of the present invention is provided with a plurality of lightening portions in the circumferential direction on the back side of the gear teeth, and the shape of the plurality of lightening portions is uneven. Periodic sound and vibration during torque transmission can be suppressed.

  The purpose of suppressing periodic sounds and vibrations during transmission of rotational force was realized by making the plurality of lightening portions non-uniformly shaped.

[Structure of ring gear]
1 is a sectional view showing a hypoid gear to which a ring gear according to a first embodiment of the present invention is applied. FIG. 2 is a plan view of the ring gear shown in FIG. It is sectional drawing in the III-III arrow of a ring gear.

  As shown in FIG. 1, the ring gear 1 is applied to a hypoid gear 2 such as a final gear of a vehicle, for example, and transmits torque to and from the other pinion gear 3.

  As shown in FIGS. 1 to 3, the ring gear 1 is manufactured through heat treatment and includes a ring-shaped main body 5. A plurality of gear teeth 7 are provided on one side of the main body 5 along the circumferential direction. The gear teeth 7 mesh with the gear teeth 8 of the pinion gear 3.

  On the other side of the main body 5 (the back side of the gear teeth 7), a plurality of fastening holes 11 are provided for every predetermined pitch in the circumferential direction. Through this fastening hole 11, the ring gear 1 is fastened and fixed to the flange portion of the differential case by a bolt. On the other side of the main body 5, a plurality of lightening portions 9 a to 9 j for weight reduction are provided.

  The plurality of lightening portions 9 a to 9 j are respectively disposed between adjacent ones of the fastening holes 11, and are formed at predetermined circumferential pitches of the main body portion 5. Each of the lightening portions is formed by a hole drilled from the other side of the main body portion 5 toward one side, and is formed in a circular shape in a plan view of FIG.

As shown in FIG. 3, each of the lightening portions is different in one or both of a depth D and a diameter R (cross-sectional shape and planar view shape). Accordingly, the shapes of the plurality of lightening portions 9a to 9j are all different and non-uniform.
[Heat treatment deformation]
The ring gear 1 of the present embodiment is heat-treated and deformed non-uniformly in the circumferential direction by making the lightening portions 9a to 9j non-uniform. In general, the ring gear has a heat treatment deformation amount corresponding to the shape of the hollow portion. Therefore, in the ring gear 1 of the present embodiment, the shapes of the thinned portions 9a to 9j are all different and nonuniform, and different heat treatment deformation amounts are set in the circumferential direction.

  As a result, the ring gear 1 is deformed by heat treatment unevenly in the circumferential direction as described above, and has a minute wave shape. The ring gear 1 has an overall rotational balance adjusted by a combination of non-uniform heat treatment deformation in the circumferential direction and the shape of the thinned portions 9a to 9j. Accordingly, the ring gear 1 can smoothly rotate when the rotational force is transmitted, and can reduce noise and vibration as in the case where the ring gear 1 is uniformly heat-treated and deformed in the circumferential direction.

  In addition, during rotation, the ring gear 1 has a minute wave shape that is heat-treated and deformed non-uniformly in the circumferential direction, so that sounds and vibrations (natural vibrations) based on the wave shape are not periodic. As a result, it is possible to suppress periodic sounds and vibrations in the specific frequency band when transmitting the rotational force.

  Further, the ring gear 1 is non-uniform with different pitches of the gear teeth 7 due to heat treatment deformation that is not uniform in the circumferential direction. For this reason, the meshing frequency of the ring gear 1 is set so as to have a different meshing wavelength for each gear tooth 7.

  Therefore, in the ring gear 1, gear noise in the same meshing frequency band is hardly generated, and periodic gear noise can be suppressed.

  The non-uniformity of the heat treatment deformation is set so that the natural frequency based on the wave shape of the ring gear 1 and the meshing frequency of the gear teeth 7 are shifted. Therefore, in this embodiment, resonance based on the natural frequency of the ring gear 1 and the meshing frequency can be suppressed.

  FIG. 4 is a chart showing the frequency of the meshing vibration of the ring gear according to the present embodiment in comparison with the frequency of the meshing vibration of the normal ring gear. In FIG. 4, the ring gear of the present embodiment is indicated by a broken line, and the normal ring gear is indicated by a solid line. In addition, the vertical axis in FIG. 4 indicates amplitude, and the horizontal axis indicates time. In a normal ring gear, the gear tooth pitch is set uniformly.

As shown in FIG. 4, the frequency of the meshing vibration of one tooth for each gear tooth is uniform at the frequency of the normal meshing vibration of the ring gear. On the other hand, at the frequency of the meshing vibration of the ring gear 1 of the present embodiment, the wavelength of the meshing vibration for one gear tooth 7 can be made non-uniform.
[Effect of Example 1]
Since the ring gear 1 of the present embodiment is provided with a plurality of lightening portions 9a to 9j in the circumferential direction on the back side of the gear teeth 7, and the shapes of the plurality of lightening portions 9a to 9j are nonuniform, Therefore, it is possible to suppress the periodic sound and vibration during the transmission of the rotational force by non-uniform heat treatment deformation.

  In particular, the ring gear 1 can suppress periodic sound and vibration in a specific frequency band based on the wave shape of heat treatment deformation, and can suppress periodic gear noise.

  Moreover, the non-uniformity of the heat treatment deformation is set so that the natural frequency based on the wave shape of the ring gear 1 and the meshing frequency of the gear teeth 7 are shifted. Therefore, in the present embodiment, resonance based on the natural frequency of the ring gear 1 and the meshing frequency can be suppressed, and periodic sound and vibration can be suppressed more reliably.

Since the shape of the lightening portions 9a to 9j is different in at least one of a plan view shape and a cross-sectional shape, it can be easily made nonuniform during molding.
Since the plurality of lightening portions 9a to 9j are provided at every predetermined pitch in the circumferential direction, the heat treatment deformation that is uneven in the circumferential direction can be easily and reliably performed only by making the shapes of the lightening portions 9a to 9j uneven. Can be done.

  5 is a plan view of a ring gear corresponding to FIG. 2 according to the second embodiment of the present invention, and FIG. 6 is a cross-sectional view of the ring gear of FIG. In this embodiment, since the basic configuration is the same as that of the above-described embodiment, the corresponding components are denoted by the same reference numerals, or the same reference numerals are denoted by A, and detailed description thereof is omitted.

  As shown in FIGS. 5 and 6, the ring gear 1 </ b> A of the present embodiment is formed by forging a plurality of hollow portions 9 a </ b> A to 9 j </ b> A by forging instead of the hollow portions 9 a to 9 j of the above embodiment.

  The plurality of lightening portions 9aA to 9jA are formed of concave portions (concave groove shape) extending along the surface direction, and are open on the inner peripheral side of the ring gear 1A. The shapes of the plurality of lightening portions 9aA to 9jA are all different and non-uniform as in the above embodiment. In addition, in the lightening portions 9aA to 9jA of the present embodiment, the depth D (cross-sectional shape), the distance H (cross-sectional shape and planar view shape) from the inner periphery of the ring gear 1A, or the circumferential width W (plan view). Any one, two or all of the shapes) are different.

The ring gear 1A of the present embodiment can produce the same effect as the above-described embodiment, and can easily form the lightening portions 9aA to 9jA by forging.
[Others]
As mentioned above, although the Example of this invention was described, this invention is not limited to this, A various change is possible.

  For example, the shape of the thinned portion only needs to be formed non-uniformly, and the planar view shape and the cross-sectional shape can be arbitrarily set.

  Moreover, the lightening part in this invention can take arbitrary shapes other than the hole shape like Example 1, or the ditch | groove shape of Example 2, and as those formation methods other than cutting and forging, A method such as sintering or casting may be used.

(Example 1) which is sectional drawing which shows the hypoid gear to which the ring gear was applied. (Example 1) which is a top view in the II arrow of the ring gear shown in FIG. FIG. 3 is a cross-sectional view of the ring gear of FIG. 10 is a chart showing the frequency of meshing vibration of a ring gear in comparison with the frequency of a normal ring gear (Example 1). (Example 2) which is a top view of a ring gear. Sectional drawing (Example 2) in the VI-VI line arrow of the ring gear of FIG.

1 Ring gear 3 Pinion gear (the other party)
7 Gear teeth 9a to 9j

Claims (3)

A ring gear that has a plurality of gear teeth in the circumferential direction and meshes with the other gear teeth to transmit rotational force,
On the back side of the gear teeth, a plurality of lightening portions are provided in the circumferential direction,
The shape of the plurality of meat removal portions was made non-uniform,
Ring gear characterized by that. The ring gear according to claim 1,
The shape of the lightening portion is different from at least one of a plan view shape and a cross-sectional shape,
Ring gear characterized by that. The ring gear according to claim 1 or 2,
The lightening portion is provided for each predetermined pitch in the circumferential direction.
Ring gear characterized by that.

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