JP4867353B2 - Shaving cutter for finishing internal gears with high hardness - Google Patents

Description

The present invention relates to a shaving cutter for finishing a hardened or hardened internal gear tooth surface.

As a conventional solid carbide cutter capable of finishing a tooth surface of a hardened or hardened internal gear by shaving, for example, in Patent Document 1, FIG. 4 (a) is a perspective view of one tooth portion. ), The tooth part 7 and the main body 17 are made of the same kind of cemented carbide as shown in the cross-sectional shape including the cutter shaft of (a) and are integrally structured, and the cutting edge 5 of the tooth part 7 is −3 ° or more− An obtuse angle shape that gives a rake angle of less than 8 ° is disclosed. FIG. 5A shows the shaving state of the shaving cutter 1 and the one tooth surface 21 of the internal gear 4, and FIG. 5B shows the shaving processing of the shaving cutter 1 and the one tooth surface 23 of the external gear 6. Indicates the state.

Gears are hardened by quenching in order to ensure their use and function. After that, there are cases where the tooth surface is used to remove heat treatment distortion and cases where the heat treatment is used as it is. The former finishing method includes a grinding finish using a threaded grindstone and a gear honing finish using a dress gear, but is not suitable for machining the internal gear 4 as shown in FIG. From these, there were very few examples of finishing methods after heat treatment of internal gears.
In recent years, the need for higher accuracy of planetary internal gears has been increasing, particularly in proportion to the spread of A / T passenger cars. In Patent Document 1, an attempt was made to use the shaving method of the planetary internal gear 4 by the externally toothed small-diameter cutter 1 shown in FIG. Since the cutter material at this time is a high-hardness gear object, a carbide solid type was used. However, the shaving process, like the external gear process shown in FIG. 5 (b), is highly efficient but requires a large pushing force in order to scrape the hard surface. In the external gear machining shown in FIG. 5 (b), a combination of the convex surface 23 and the convex surface 22 is used. As shown in FIG. 5 (a), the tooth surface 20 to be machined of the internal gear 4 and the cutting blade 5 of the shaving cutter 1 Since the combination of the tooth surface curvatures is the concave surface 21 and the convex surface 22, the contact surface area between the tooth surfaces is wider than that of the external gear. Accordingly, it is not easy to cause the cutting blade 5 of the shaving cutter 18 to bite into the quenched internal gear tooth surface. Therefore, a large indentation load is required to give a surface pressure above a certain level, and the cutting edge is easily eroded with the cutter tooth shape for processing a soft material that is not normally quenched as shown in FIG. It was not attached, and as a result, it was found to be deficient early.

  An object of the present invention is a solid carbide cutter capable of finishing a tooth surface of a hardened or hardened internal gear by a shaving process, and a shaving cutter shape for finishing a hardened internal gear suitable for reducing tooth defects. Is to provide.

Therefore, the present invention is a hardened or high-hardness shaving cutter for tooth surface finishing of an internal gear, which has one tooth or a plurality of cutting edges in the tooth part, and each end face of the tooth part is perpendicular to the axis. A high-hardness internal gear finish characterized by being formed with an inclined end surface having an inclination angle α of 15 ° to 60 °, and the tooth portion having the inclined end surface does not have a tooth surface serving as a cutting edge. The above-described problems of the present invention have been solved by providing a shaving cutter for use. More preferably, each tooth portion has two cutting edges, each end surface of the tooth portion is formed by an inclined end surface having an inclination angle α of about 45 ° with respect to an axis perpendicular, and the inclination A high-hardness internal gear finishing shaving cutter having no tooth surface serving as a cutting edge at a tooth portion having an end surface is provided.

  When the problem of the present invention is viewed from the cutter side, insufficient tooth strength is one of the major factors. However, one of the disadvantages of cemented carbide is the lack of bending stress, and it must have a tooth shape that can withstand the large indentation load described above. According to the present invention, the tooth portion has one or a plurality of cutting edges, and each end surface of the tooth portion is formed of an inclined end surface having an inclination angle of 15 ° to 60 ° with respect to the axis perpendicular. Since the cross-sectional shape including the cutter shaft is changed from the rectangular shape shown in FIG. 4B to the trapezoidal shape, the cutter outer peripheral width is almost the serrated cutting edge existing width and the tooth base receiving the largest bending stress is obtained. The width was 1.5 to 10 times the upper side of the trapezoid, improving the bending strength of the teeth. What is more characteristic is that there is no cutting edge in a portion having an inclined end surface shape. This is a shaving cutter for finishing high-hardness internal gears that minimizes the number of cutting edges (contact area between tooth surfaces with the internal gear) and increases the inter-tooth surface pressure to improve the biting characteristics of the cutting edges. It became something to offer.

  An example of the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional shape including a cutter shaft of one tooth portion of a shaving cutter for finishing a high-hardness internal gear according to the first embodiment of the present invention, and FIG. 2 shows a height of a second embodiment of the present invention different from FIG. FIG. 3A is a perspective view of one tooth portion of a shaving cutter for finishing internal gear, FIG. 3A is a plan view of the cutter having the tooth portion of FIG. 2, and FIG. 3B is a side view of FIG.

  As shown in FIG. 1, the high-hardness internal gear finishing shaving cutter according to the first embodiment of the present invention is a hardened or high-hardness internal gear tooth surface finishing shaving cutter 9, The end face 16a, 16b of the tooth portion 17 is formed of inclined end faces 12, 12 having an inclination angle α of 15 ° or more and 60 ° or less with respect to the perpendicular 19 of the axis, and having one or a plurality of cutting edges 25, and The tooth part 17 having the inclined end faces 12 and 12 is characterized in that it does not have a tooth surface that becomes a cutting edge. In the high-hardness internal gear finishing shaving cutter according to the second embodiment of the present invention shown in FIG. 2, each tooth portion 13 has two cutting edges 14, and each end face 26 a, 26 b of the tooth portion 13 has an axis perpendicular 19. On the other hand, it is formed by inclined end faces 12 and 12 having an inclination angle α of about 45 °.

  When the problem of the present invention is viewed from the cutter side, insufficient tooth strength is one of the major factors. However, one of the disadvantages of cemented carbide is the lack of bending stress, and it must have a tooth shape that can withstand the large indentation load described above. With this configuration, the shaving cutter for finishing the internal gear finishing with high hardness according to the embodiment of the present invention has one blade or a plurality of cutting blades 14 and 15 on the tooth portions 17 and 13, and end surfaces 16 a and 16 b of the tooth portions 17 and 13. 26a and 26b are formed with inclined end faces 12 and 12 having an inclination angle α of 15 ° or more and 60 ° or less with respect to the normal 19 of the axis, and the sectional shape including the cutter shaft is shown in FIG. Since the rectangular shape 8 is changed to the trapezoidal shape shown in FIGS. 1 and 2, the cutter outer peripheral width 10 is approximately the serrated cutting edge 14, 15 existence width, and the tooth root width 11 that receives the largest bending stress is the cutter outer peripheral width 10. That is, the trapezoidal upper side width 10 was set to 1.5 to 10 times, and the bending strength of the tooth portions 17 and 13 and the cutting blades 14 and 15 was improved. What is more characteristic is that there is no cutting edge in the portion having the inclined end faces 12 and 12. This is a shaving cutter for finishing high-hardness internal gears that minimizes the number of cutting edges (contact area between tooth surfaces with the internal gear) and increases the inter-tooth surface pressure to improve the biting characteristics of the cutting edges. It became something to offer.

  A hardened internal gear finishing shaving cutter having the shape shown in FIG. 2 and FIG. 3 is used to finish the hardened internal gear finishing shaving. The conventional high hardness internal gear finishing shaving shown in FIG. Compared to the cutter, the breakage rate of the cutter teeth was greatly reduced from 70% to 8%. In addition, since the cutting edge existence width is kept to the minimum effective width, the time required for grinding the tooth surface of the cemented carbide cutter can be shortened from about 4H to 3H. Furthermore, the cutter weight could be reduced, and the effect of reducing the material cost was also obtained.

The cross-sectional shape containing the cutter shaft of 1 tooth part of the shaving cutter for high-hardness internal gear finishing of 1st Embodiment of this invention is shown. The perspective view of 1 tooth | gear part of the shaving cutter for high-hardness internal gear finishing of 2nd Embodiment of this invention different from FIG. (A) is a top view of the cutter which has a tooth | gear part of FIG. 2, (b) shows the side view of (a). (A) is a perspective view which shows one tooth | gear part of the cemented carbide cutter of patent document 1, (b) shows the cross-sectional shape containing the cutter axis | shaft of (a). (A) shows the shaving processing state of the shaving cutter and one tooth surface of the internal gear, and (b) shows the shaving processing state of the shaving cutter and one tooth surface of the external gear.

Explanation of symbols

9: Shaving cutter for finishing internal gears with high hardness, 12, 12: Inclined end face
16a, 16b, 26a, 26b: tooth end faces, 13, 17: tooth, 14, 15: cutting edge, 19: axis perpendicular α: angle of inclination

Claims (2)

  A shaving cutter for hardened or hardened internal gear tooth surface finishing, which has one or more cutting edges in the tooth portion, and each end surface of the tooth portion is at least 15 ° with respect to the axis perpendicular 60 A shaving cutter for finishing a high-hardness internal gear, characterized in that it is formed of an inclined end face having an inclination angle α of less than or equal to 0 °, and the tooth portion having the inclined end face does not have a tooth face serving as a cutting edge. Each tooth portion has two cutting edges, each end surface of the tooth portion is formed by an inclined end surface having an inclination angle α of about 45 ° with respect to the axis perpendicular, and the tooth portion having the inclined end surface 2. The shaving cutter for finishing a high-hardness internal gear according to claim 1, wherein said shaving cutter has no tooth surface as a cutting edge.

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