Pressing structure of shaft and shaft hole

Abstract

The invention provides a pressing structure of a shaft and a shaft hole, which can accurately press the shaft into the shaft hole with high precision, can fully obtain the pressed-in range, and can realize the firm pressed-in joint. In the shaft (2) and the shaft hole (1) into which the shaft (2) is pressed, the opening end of the shaft hole (1) is formed with an opening end face (11), an inclined plane guiding part (12) expanded toward the opening end is formed at the side of a pressed-in hole part (14) of the shaft hole (1), a steeply inclined plane guiding part (13) expanded from the side of the inclined plane guiding part (12) to the opening end face (11) is formed between the opening end face (11) and the inclined plane guiding part (12). The inclination of the inclined plane of the steeply inclined plane guiding part (13) is more than that of the inclined plane of the inclined plane guiding part (12), and the opening end face (11) is in a flat conical shape.

Description

technical field [0001] The invention relates to a press-fitting structure of a shaft and a shaft hole: when the shaft is pressed into the shaft hole, the shaft can be accurately pressed into the shaft hole with extremely high precision, and the pressing-in range can also be fully obtained. A secure press fit is achieved. Background technique [0002] In general, in the field of machinery (eg, motor vehicles), press-fitting as a fastening mechanism in a shaft and its shaft hole is generally performed widely. As one example, press-fitting of a rod-shaped shaft and a pulley having a hole with an inner diameter slightly smaller than the outer diameter of the shaft is widely performed. As a fastening mechanism between a shaft and a pulley, fastening by bolts is widely performed, but fastening by press-fitting is inexpensive in terms of manufacturing cost, and thus is advantageous. Furthermore, compared with the tightening by bolts, the tightening mechanism by press fitting can ...

AI Technical Summary

Problems solved by technology

If the chamfer is deepened (increased) along the depth direction of the hole, the above-mentioned problems can be solved, but when the depth of the chamfer is deepened, the depth of the pressed hole becomes shallower accordingly

That is, the effective length of press-fitting is shortened, so the press-fitting strength is reduced

[0019] However, in the techniques disclosed in the aforementioned Patent Documents 1 to 3, the opening diameter of the pulley hole is further increased by chamfering the opening of the pulley hole, and the shaft hole is arranged at the top of the front end of the shaft before the start of press-fitting. When pressure is applied, the shaft tends to be skewed with respect to the center axis of the shaft hole, and the angle of inclination becomes large.

This is because the larger the opening diameter of the end face opening of the shaft hole, the larger the gap between the outer diameter of the front end of the shaft and the opening diameter of the opening of the shaft hole, resulting in looseness, which tends to be further skewed.

[0020] That is, in the shape of the chamfered portion of Patent Document 1 to Patent Document 3, there is an advantage in that press-fitting is easy, but due to the shape of the chamfer, skewing of the shaft is likely to occur, and as a result, as described above, When used as a pulley, etc., there are problems of reduced belt life and increased belt operation noise

Also, conversely, when the inclination angle of the chamfered slope is steepened to reduce the press-fit distortion, the opening diameter of the chamfered end face becomes small, making it difficult to absorb the lateral (diametrical) misalignment of the axis.

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