JP6969534B2 - Shaft member fitting structure - Google Patents

Description

The present invention relates to a fitting structure of a shaft member.

Conventionally, there is Japanese Patent Application Laid-Open No. 11-108070 as a technique in such a field. In the fitting structure described in this publication, internal teeth and external teeth are formed on the inner and outer sides of the shaft member, respectively, and the tooth tip surface of any of the external teeth is in contact with the tooth bottom surface of the internal teeth. A first press-fitting portion that is mutually deformed, and a second press-fitting portion that is mutually deformed by abutting the tooth surface of an external tooth other than the external tooth on which the first press-fitting portion is formed and the tooth surface of the internal tooth. , Are stated to be provided. The first press-fitting portion and the second press-fitting portion are provided so as to be alternately continuous.

Japanese Unexamined Patent Publication No. 11-108070

However, although the above-mentioned conventional fitting structure can be expected to have a stress reducing effect, cracks may occur when the effect is insufficient. Specifically, depending on the shape of the shaft member and the press-fitting allowance, stress may be concentrated on the tooth bottom of the second press-fitting portion, and cracking due to delayed fracture may occur. Therefore, there is a desire to reduce the bending stress applied to the shaft member and reduce the stress generated in the second press-fitting portion.
The present invention provides a fitting structure for a shaft member that suppresses the occurrence of cracks in the shaft member.

The fitting structure of the shaft member according to the present invention is continuously provided with a plurality of first press-fitting portions that abut the tooth tip surface of the external tooth and the tooth bottom surface of the internal tooth and deform each other. Of the plurality of first press-fitting portions, they are arranged between adjacent first press-fitting portions, and the tooth surface of the external tooth and the tooth surface of the internal tooth are abutted and press-fitted, and the tooth tip surface and the inner surface of the external tooth are press-fitted. It is provided with a second press-fitting portion that is contact-press-fitted by contact-press-fitting the tooth bottom surface of the tooth and is mutually deformed.
As a result, the stress generated in the second press-fitting portion can be reduced.

Thereby, it is possible to provide a fitting structure of the shaft member in which the occurrence of cracking of the shaft member is suppressed.

It is a figure of the 1st press-fitting part. It is a figure of the 2nd press-fitting part. It is a figure which shows the stress applied in the 1st press-fitting part, the 2nd press-fitting part, and the intermediate between them. It is a figure which shows the stress applied to the 2nd press-fitting part. It is a figure which showed the suppression of cracking and the state of occurrence. It is a figure which showed the comparison of the generated stress.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a first press-fitting portion in the fitting structure 100 according to an embodiment of the present invention. FIG. 2 is an explanatory view of a second press-fitting portion in the fitting structure 100 according to the embodiment of the present invention.

As shown in FIGS. 1 and 2, the first shaft member 1 and the second shaft member 2 have a large-diameter press-fitting allowance in which a press-fitting allowance is set in the radial direction and a tooth surface in which a press-fitting allowance is set in the tooth surface direction. Fitted by press fitting. Here, the first shaft member 1 will be described as an external tooth spline, and the second shaft member 2 will be described as an internal tooth spline.

The fitting structure 100 according to an embodiment of the present invention includes a tooth 10 used in the first press-fitting portion as shown in FIG. 1 and a tooth 11 to be fitted in the second press-fitting portion as shown in FIG. Is configured to include.

Here, in the first shaft member 1, the two tooth surfaces arranged between the tooth tip 1a and the tooth bottom 1d are referred to as a tooth surface 1b and a tooth surface 1c. Here, as shown in FIG. 1, the tooth surface between the tooth tip 1a and the tooth bottom 1d arranged on the left side thereof is the tooth surface 1b, the tooth tip 1a and the tooth bottom 1d arranged on the right side thereof. The tooth surface between them is defined as the tooth surface 1c.

Similarly, in the second shaft member 2, the two tooth surfaces arranged between the tooth tip 2a and the tooth bottom 2d are the tooth surface 2b and the tooth surface 2c.

As shown in FIG. 1, in the first press-fitting portion, in the tooth 10, the large-diameter press-fitting allowance A indicated by a dotted ellipse is between the tooth tip 1a of the first shaft member 1 and the tooth bottom 2d of the second shaft member 2. Is set. That is, in the first press-fitting portion, the tooth tip surface of the external tooth and the tooth bottom surface of the internal tooth are in contact with each other and are deformed to each other.

As shown in FIG. 2, in the second press-fitting portion, in the tooth 11, a large-diameter press-fitting allowance B indicated by a dotted ellipse is formed between the tooth tip 1a of the first shaft member 1 and the tooth bottom 2d of the second shaft member 2. Set. Further, a tooth surface press-fitting allowance C indicated by a dotted ellipse is set between the tooth surface 1b and the tooth surface 2b, and a tooth surface press-fitting allowance D indicated by a dotted ellipse is set between the tooth surface 1c and the tooth surface 2c.

Here, as shown in FIG. 3, the second press-fitting portion is arranged between the adjacent first press-fitting portions. That is, the first press-fitting portion and the second press-fitting portion are alternately and continuously arranged. Further, in other words, in the second press-fitting portion, the tooth surface of the external tooth and the tooth surface of the internal tooth are contact-press-fitted, and the tooth tip surface of the external tooth and the internal tooth are press-fitted. By press-fitting the tooth bottom, the tooth bottom is contact-press-fitted and deformed to each other.

Next, the advantages of the fitting structure described above will be described with reference to FIGS. 3 to 5. Here, in FIG. 3, an arrow is used to indicate the direction of stress. In the conventional fitting structure, the second press-fitting portion is provided with a tooth surface press-fitting allowance and the tooth surface is press-fitted, but the large-diameter press-fitting is not performed.

As shown in FIG. 3A, it is assumed that in the fitting structure 100, one second press-fitting portion is arranged so as to be sandwiched between the two first press-fitting portions. In this second press-fitting portion, stress in the radial direction is generated due to the large-diameter press-fitting, and stress in the circumferential direction is generated due to the press-fitting on the tooth surface. It should be noted that even in the first press-fitting portion, stress in the radial direction is generated due to the large-diameter press-fitting.

That is, in the fitting structure 100, radial stress is generated in both the first press-fitting portion and the second press-fitting portion. Therefore, as shown in FIG. 3B, in the conventional fitting structure, the radial stress is generated only in the first press-fitting portion, whereas in the fitting structure 100, the radial stress is generated. The distance you are in is shortened. Therefore, in the fitting structure 100, the stress in the circumferential direction can be reduced between the first press-fitting portion and the second press-fitting portion.

Further, as shown in FIG. 4A, in the fitting structure 100, the tooth bottom 2d of the second shaft member 2 is radially outward due to the tooth tip 1a of the first shaft member 1 due to the large diameter press-fitting in the second press-fitting portion. Is pushed to. As a result, the force of the tooth surfaces 1b and 1c of the first shaft member 1 (see FIG. 2) to spread the tooth surfaces 2b and 2c of the second shaft member 2 becomes smaller, respectively. Therefore, in the fitting structure 100, the stress in the circumferential direction at the second press-fitting portion can be reduced.

Here, in the conventional fitting structure shown in FIG. 4B, since there is no stress in the radial direction, the tooth surface of the first shaft member has a large force to push the tooth surface of the second shaft member. Therefore, a large stress is generated in the circumferential direction in the second shaft member.

Due to these effects, as shown in FIG. 5A, in the fitting structure 100, the stress in the circumferential direction applied to the tooth bottom 2d (see FIG. 2) in the second shaft member becomes small, so that the occurrence of cracks is suppressed. be able to. That is, in the conventional fitting structure as shown in FIG. 5B, the maximum stress yields even when the stress in the circumferential direction applied to the second shaft member exceeds the yield stress and cracks occur. It is possible not to exceed the stress.

For example, as shown in FIG. 6, when the yield stress is 1.8 GPa, the maximum stress is 1.94 GPa in the conventional fitting structure and cracking occurs. However, in the fitting structure 100 shown above, the yield stress is 1.94 GPa. The maximum stress can be suppressed to 1.64 GPa. Therefore, in the fitting structure 100, the occurrence of cracks can be suppressed.

As described above, the stress generated in the second shaft member 2 is applied to the location of the second press-fitting portion and the first by setting the state in which both the large-diameter press-fitting and the tooth surface press-fitting are performed in the second press-fitting portion. It can be suppressed at a position between the press-fitting portion and the second press-fitting portion. Therefore, it is possible to suppress the occurrence of cracks in the second shaft member 2.

INDUSTRIAL APPLICABILITY The present invention is suitably used for a structure for integrally connecting an annular member such as a gear or a hub to a rotating shaft of a transmission or a transfer mounted on a vehicle or the like.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

1 1st shaft member 1a Tooth tip 1b Tooth surface 1c Tooth surface 1d Tooth bottom 2 2nd shaft member 2a Tooth tip 2b Tooth surface 2c Tooth surface 2d Tooth bottom 10 Tooth 11 Tooth 100 Fitting structure

Claims (1)

It is a fitting structure of shaft members such as spline press-fitting.
A plurality of first press-fitting portions that abut the tooth tip surface of the external tooth and the tooth bottom surface of the internal tooth and deform each other.
Of the plurality of first press-fitting portions continuously provided, the first press-fitting portions are arranged between adjacent first press-fitting portions, and the tooth surface of the external tooth and the tooth surface of the internal tooth are contact-press-fitted and externally provided. A fitting structure of a shaft member including a second press-fitting portion in which the tooth tip surface of the tooth and the tooth bottom surface of the internal tooth are contact-press-fitted and mutually deformed.

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