JP2017104890A - Method for manufacturing helical gear with shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily give and change crowning of a helical gear.SOLUTION: A method for manufacturing a helical gear 10 with a shaft comprises a step at which a helical gear 11 having teeth on an outer peripheral surface thereof and a shaft 12 are separately manufactured, and a step at which the shaft 12 is pressed and fitted in a through hole 111 formed on a midship part of the helical gear 11. Crowning is given to the teeth of the helical gear 11 in such a manner that a press-in margin on a longitudinal direction midship part 112 of the shaft 12 is so made as to be larger than a press-in margin on longitudinal direction both ends 113, 114 in the fitting part between the helical gear 11 and the shaft 12.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a helical gear with a shaft.

  A helical gear having teeth on the outer peripheral surface may impart crowning to the teeth. As an apparatus which can give crowning to a helical gear, the cold forging apparatus disclosed by patent document 1 is mentioned.

  The cold forging device disclosed in Patent Document 1 is provided with a ring mold having a molded tooth (molded portion) on the inner periphery with which a coarse tooth of a material (corresponding to a helical gear) meshes, and the ring mold in the axial direction By adjusting the amount of elastic deformation, the material is crowned.

JP 2002-126847 A

  However, in the cold forging device disclosed in Patent Document 1, in order to change the crowning of the helical gear, it is necessary to finely adjust the amount of elastic deformation of the ring type, and it is extremely difficult to change the crowning. was there

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a helical gear with a shaft that can easily impart and change crowning of the helical gear.

According to one aspect of the present invention, a method for manufacturing a helical gear with a shaft includes:
Separately manufacturing a helical gear having teeth on the outer peripheral surface and a shaft;
Press fitting the shaft into a through hole formed in the central portion of the helical gear, and
In the fitting portion between the helical gear and the shaft, the press-fitting allowance at the central portion in the longitudinal direction of the shaft is made larger than the press-fitting allowance at both end portions in the longitudinal direction, thereby giving crowning to the teeth of the helical gear.

  According to the aspect mentioned above, the effect that the crowning of a helical gear can be easily provided and changed by changing the press-fitting allowance in the fitting part of a helical gear and a shaft is acquired.

It is front sectional drawing which shows roughly an example of the helical gear 10 with a shaft concerning Embodiment 1. FIG. 1 is a front sectional view schematically showing an example of a shaft 12 according to a first embodiment. It is A-A 'sectional drawing of FIG. 2A. 1 is a front sectional view schematically showing an example of a helical gear 11 according to a first embodiment. It is A-A 'sectional drawing of FIG. 3A. 2A and 2B are front sectional views schematically showing an example of the helical gear with shaft 10 according to the first embodiment, in which the shaft 12 shown in FIGS. 2A and 2B is press-fitted into the helical gear 11 shown in FIGS. 3A and 3B. . FIG. 6 is a front sectional view schematically showing an example of a planetary ring gear 41 and a case according to a second embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

(1) Embodiment 1
The first embodiment relates to a helical gear with a shaft with a shaft.
(1-1) Structure of Helical Gear 10 with Shaft FIG. 1 is a front sectional view schematically showing an example of the helical gear 10 with shaft according to the first embodiment. For comparison, FIG. 1 also shows a helical gear 100 with a shaft according to the prior art. Moreover, FIG. 1 shows that the structure of the helical gear portion of the helical gears 10 and 100 with shafts varies depending on the gear ratio.

As shown in FIG. 1, the helical gear 100 with a shaft according to the prior art has a structure in which a shaft and a helical gear are integrally formed.
Therefore, when manufacturing the helical gear 100 with a shaft having a different gear ratio, it is necessary to remodel the entire helical gear 100 with a shaft.

  On the other hand, the helical gear with shaft 10 according to the first embodiment has a structure in which the helical gear 11 and the shaft 12 are divided, and the shaft 12 is press-fitted into a through hole 111 formed in the central portion of the helical gear 11 for fitting. It has become.

Therefore, when manufacturing the helical gear 10 with a shaft having different gear ratios, it is only necessary to make the shaft 12 common and to reconstruct only the helical gear 11.
Moreover, since the shaft 12 and the helical gear 11 may be manufactured separately and combined, the helical gear with shaft 10 can be manufactured efficiently.
Further, since the helical gear 11 has a simple shape, it can be manufactured at a low cost by, for example, a continuous steady extrusion method. However, the manufacturing method of the helical gear 11 is not limited to the continuous steady extrusion method, and general tooth profile processing (hob, gear shaper, etc.) may be used.

  The helical gear with shaft 10 has a structure that provides crowning of teeth on the outer peripheral surface of the helical gear 11 by changing the press-fitting allowance at the fitting portion between the helical gear 11 and the shaft 12. Specifically, in the fitting portion, the press-fitting allowance at the central portion in the longitudinal direction of the shaft 12 is made larger than the press-fit allowance at both ends in the longitudinal direction.

Conventionally, when the crowning of the helical gear 11 is changed, it is necessary to finely adjust the elastic deformation amount of the ring type as in the cold forging device disclosed in Patent Document 1. Conventionally, when crowning is applied to the helical gear 11, first, the helical gear 11 that does not have the crowning is manufactured, and thereafter, post-processing such as rolling and shaving is performed to provide crowning to the helical gear 11. There was also.
On the other hand, in the first embodiment, the crowning of the helical gear 11 can be easily applied and changed by changing the press-fitting allowance at the fitting portion between the helical gear 11 and the shaft 12. Further, since the crowning of the helical gear 11 can be easily applied in this way, it is not necessary to perform post-processing such as rolling or shaving for the application of crowning after the helical gear 11 is manufactured. Details of the press-fitting allowance of the helical gear 11 will be described later.

  Moreover, the helical gear 10 with a shaft has a structure in which the helical gear 11 and the shaft 12 are press-fitted by a spline 121 so that the same function as the helical gear 100 with a shaft according to the prior art is exhibited.

(1-2) Press-fit allowance of the helical gear 11 FIG. 2A and FIG. 2B are diagrams schematically showing an example of the shaft 12 according to the first embodiment, FIG. 2A is a front sectional view, and FIG. It is -A 'sectional drawing.
As shown in FIGS. 2A and 2B, the shaft 12 has a spline 121 formed on the outer peripheral surface thereof. In FIG. 2A, D1 is defined as the outer diameter of the shaft 12.

3A and 3B are diagrams schematically illustrating an example of the helical gear 11 according to the first embodiment, in which FIG. 3A is a front sectional view, and FIG. 3B is a sectional view taken along line AA ′ of FIG. 3A.
As shown in FIGS. 3A and 3B, the helical gear 11 has teeth on the outer peripheral surface, and a through hole 111 is formed in the center. In FIG. 3A, D2 is defined as the inner diameter of the helical gear 11.

Here, the outer diameter D1 of the shaft 12 is larger than the inner diameter D2 of the helical gear 11. The difference between the outer diameter D1 and the inner diameter D2 is defined as α.
Further, as shown in FIG. 4, the shaft 12 is press-fitted into a through hole 111 formed in the central portion of the helical gear 11 to be fitted. In this fitting portion, the central portion in the longitudinal direction of the shaft 12 is defined as the longitudinal central portion 112, and both end portions in the longitudinal direction are defined as the longitudinal both end portions 113 and 114.

  As described above, the outer diameter D1 of the shaft 12 is larger than the inner diameter D2 of the helical gear 11, and the difference is α. Therefore, the longitudinal center portion 112 in the fitting portion between the helical gear 11 and the shaft 12 has a press-fitting allowance of α. On the other hand, for example, the press-fitting allowance is zero at the longitudinal ends 113 and 114 in the fitting portion. Due to such a difference in the press-fitting allowance, the longitudinal center portion 112 in the fitting portion is raised in the direction in which the diameter dimension increases. Thereby, pseudo crowning is imparted to the teeth on the outer peripheral surface of the helical gear 11.

As described above, in the first embodiment, the crowning of teeth on the outer peripheral surface of the helical gear 11 is imparted by changing the press-fitting allowance at the fitting portion between the helical gear 11 and the shaft 12. Specifically, in the fitting portion, the press-fitting allowance at the longitudinal center portion 112 is made larger than the press-fit allowances at the longitudinal end portions 113 and 114.
Thus, by changing the press-fitting allowance at the fitting portion between the helical gear 11 and the shaft 12, the crowning of the helical gear 11 can be easily applied and changed. Further, since the crowning of the helical gear 11 can be easily applied in this way, it is not necessary to perform post-processing such as rolling or shaving for the application of crowning after the helical gear 11 is manufactured.

  Here, in Embodiment 1, the dimensions of the outer diameter D1 of the shaft 12 and the inner diameter D2 of the helical gear 11 are not particularly limited. The dimensions of the outer diameter D1 and the inner diameter D2 may be any dimensions as long as the shaft 12 can be press-fitted into the helical gear 11 and crowning can be imparted to the helical gear 11.

  In the first embodiment, the press-fitting allowance in the fitting portion is changed at the three locations of the longitudinal center portion 112 and the longitudinal end portions 113 and 114, but is not limited to this. The press-fitting allowance in the fitting portion may be continuously changed like a curve. Moreover, although the cross-sectional shape of the press-fitting portion is the spline 121 and its large diameter is illustrated and described, it may be a small diameter, or may be a connecting line connecting the large diameter and the small diameter of the spline 121 or a combination portion thereof. . Further, the cross-sectional shape itself may be an arc or an ellipse.

(2) Embodiment 2
The second embodiment relates to a planetary ring gear that is used in a planetary gear mechanism (planetary gear) and has teeth on an inner peripheral surface.
In general, the teeth on the inner peripheral surface of the planetary ring gear are formed by broaching, and thereafter, processing for imparting crowning is not performed. The reason is that the planetary ring gear has teeth on the inner peripheral surface, so that it is difficult to perform processing such as rolling and shaving.

When the planetary gear mechanism is used in a vehicle, in order to improve the NV (Noise and Vibration) performance in the vehicle, it is preferable to have a configuration in which crowning is applied to the planetary ring gear. There is a concern that the cost will increase.
Therefore, the second embodiment provides a configuration that provides crowning to the planetary ring gear at low cost.

FIG. 5 is a front sectional view schematically showing an example of the planetary ring gear 41 and the case 42 according to the second embodiment.
As shown in FIG. 5, in the second embodiment, the planetary ring gear 41 and the case 42 are divided, and the planetary ring gear 41 is press-fitted into the case 42 and engaged. In FIG. 5, D1 is defined as the outer diameter of the planetary ring gear 41, and D2 is defined as the inner diameter of the case 42. Further, in the fitting portion when the planetary ring gear 41 is fitted to the case 42, the central portion in the axial direction of the planetary ring gear 41 is defined as the axial central portion 411, and both end portions in the axial direction are defined as both axial end portions 412 and 413. To do.

Here, the outer diameter D 1 of the planetary ring gear 41 is larger than the inner diameter D 2 of the case 42. The difference between the outer diameter D1 and the inner diameter D2 is defined as α.
As described above, the outer diameter D1 of the planetary ring gear 41 is larger than the inner diameter D2 of the case 42, and the difference is α. Therefore, the axial center portion 411 in the fitting portion between the planetary ring gear 41 and the case 42 has a press-fitting allowance of α. On the other hand, the axial insertion end portions 412 and 413 in the fitting portion have, for example, zero press allowance. Due to such a difference in the press-fitting allowance, the axial center portion 411 in the fitting portion is contracted in a direction in which the diameter dimension is reduced. Thereby, pseudo crowning is imparted to the teeth on the inner peripheral surface of the planetary ring gear 41.

As described above, the second embodiment has a structure in which crowning of teeth on the inner peripheral surface of the planetary ring gear 41 is imparted by changing the press-fitting allowance at the fitting portion between the planetary ring gear 41 and the case 42. ing. Specifically, in the fitting portion, the press-fitting allowance at the axial center portion 411 is made larger than the press-fitting allowances at the axial end portions 412 and 413.
Thus, the crowning of the planetary ring gear 41 can be easily applied and changed by changing the press-fitting allowance at the fitting portion between the planetary ring gear 41 and the case 42.

Moreover, the provision and change of the crowning of the planetary ring gear 41 can be realized with a low-cost configuration in which the press-fitting allowance at the fitting portion between the planetary ring gear 41 and the case 42 is changed.
Further, by adopting a structure in which the planetary ring gear 41 is press-fitted into the case 42, pre-compression is applied to the tooth bottom portion of the teeth on the inner peripheral surface, and it is expected that the strength of the tooth profile can be improved. Therefore, the size of the planetary ring gear 41 can be reduced, and the overall unit can be reduced in size.

  Here, in Embodiment 2, the dimensions of the outer diameter D1 of the planetary ring gear 41 and the inner diameter D2 of the case 42 are not particularly limited. The dimensions of the outer diameter D1 and the inner diameter D2 may be any dimensions as long as the planetary ring gear 41 can be press-fitted into the case 42 and the planetary ring gear 41 can be crowned.

  In the second embodiment, the press-fitting allowance at the fitting portion is changed at three locations of the axial center portion 411 and the axial end portions 412 and 413, but is not limited thereto. The press-fitting allowance in the fitting portion may be continuously changed like a curve.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Helical gear with a shaft 11 Helical gear 111 Through-hole 112 Longitudinal center part 113,114 Both longitudinal end parts 12 Shaft 121 Spline 41 Planetary ring gear 411 Axis direction center part 412 and 413 Axial direction both end part 42 Case

Claims (2)

Separately manufacturing a helical gear having teeth on the outer peripheral surface and a shaft;
Press fitting the shaft into a through hole formed in the central portion of the helical gear, and
In the fitting portion between the helical gear and the shaft, crowning is imparted to the teeth of the helical gear by making the press-fitting allowance at the longitudinal center portion of the shaft larger than the press-fitting allowance at both longitudinal ends.
Manufacturing method of helical gear with shaft. Separately manufacturing a ring gear having teeth on the inner peripheral surface and a case;
And press-fitting the ring gear into the case for fitting,
In the fitting portion between the case and the ring gear, by making the press-fitting allowance at the axial center part of the ring gear larger than the press-fitting allowance at both axial ends, crowning is imparted to the teeth of the ring gear.
A method of manufacturing a planetary ring gear.

Images