JP5777860B2 - Finish polishing method for face gear - Google Patents

Description

  The present invention relates to a finish polishing method for a face gear having a twist angle preferably used for, for example, an orthogonal reduction gear.

  A face gear having a torsion angle has an orthogonal output structure that achieves high efficiency, low vibration, and low noise, but no method for finishing the tooth surface with high accuracy and mass production has been established at present. For example, in the processing of a bevel gear using an annular rack type processing tool having a CBN (cubic boron nitride) electrodeposited abrasive grain layer at the cutting edge, an electrodeposition grindstone for rough machining is provided outside or inside the electrodeposition grindstone for finishing. By using a bevel gear machining tool with a configuration to mount one, finishing one tooth groove and roughing the next tooth groove with one index, shortening the machining time or improving the machining accuracy and improving the tool life There is one designed to improve (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2005-66737 (first page, FIG. 1)

  In the conventional technology as described above, although the tool life can be improved and a bevel gear with high finished surface accuracy can be efficiently produced, when finishing a face gear having a helix angle, In a cylindrical grinder or the like, there is a problem that it is difficult to efficiently polish a face gear having a twist angle because a grindstone interferes.

  The present invention has been made in view of the actual situation of the prior art as described above. A face gear that can be efficiently finished and polished by using a general-purpose processing machine for finishing a face gear having a twist angle. The object is to provide a finish polishing method.

The face gear finish polishing method according to the present invention is a method for processing a tooth portion of the face gear by fixing a face gear having a twist angle meshing with a pinion to a pedestal of a general-purpose hobbing machine or an NC hobbing machine. A screw that is formed so as to mesh with the tooth portion of the face gear when the gear tooth portion is finish-polished by the general-purpose hobbing machine or the NC hobbing machine , and has the same shape as the pinion and has electrodeposited abrasive grains on the surface. The grindstone having the shape portion is used for polishing by synchronously rotating the face gear and the grindstone in a meshed state in which the radial cutting feed of the grindstone is applied, and at the same time the radial cutting feed of the grindstone is given. The cutting wheel feed in the axial direction of the grindstone is given, and the feed amount in the axial direction of the grindstone and rotation correction are given.

In the present invention, when a face gear tooth portion having a torsion angle meshing with a pinion is finish-polished by a general-purpose hobbing machine or an NC hobbing machine , it is formed so as to mesh with the toothed portion of the face gear. Since a grindstone having a screw-shaped portion with a surface electrodeposited with abrasive grains is used and polishing is performed by synchronously rotating the face gear and the grindstone in a meshed state in which the radial cutting of the grindstone is applied. Because there is no interference between the grindstone and the face gear that is the object to be processed, and no special processing machine is required, it is easy to process with high precision using general-purpose machines such as general-purpose hobbing machines and NC hobbing machines. This makes it possible to reduce the manufacturing cost, while providing the grinding wheel in the radial direction and at the same time providing the grinding wheel in the axial direction. For example, the feed amount of the axial direction of the grinding wheel. Thus impart rotational correction, thereby improving the surface finish in one finish polishing operation.

Engagement between a face gear and a pinion-shaped grindstone having a thread-like portion meshing with the tooth portion for finishing the tooth portion of the face gear in the finish polishing method for a face gear according to Embodiment 1 of the present invention The perspective view which shows a relationship notionally. The figure which shows notionally the state when performing the process shown by FIG. 1 with a general purpose hobbing machine. The side view which shows notionally the modification of the grindstone for finishing the tooth | gear part of a face gear. FIG. 3 is a side cross-sectional view showing the main part of the orthogonal shaft reduction gear using the face gear obtained by the face gear finish polishing method according to Embodiment 1 of the present invention. FIG. 3 is a cross-sectional view of a main part when the geared motor using the face gear obtained by the face gear finish polishing method according to Embodiment 1 of the present invention is viewed in the plane direction;

Embodiment 1 FIG.
FIG. 1 shows a face gear in a finish polishing method for a face gear according to Embodiment 1 of the present invention, and a pinion-shaped grindstone having a screw-like portion meshing with the tooth portion for finishing the tooth portion of the face gear. FIG. 2 is a diagram conceptually showing a state when the processing shown in FIG. 1 is performed by a general-purpose hobbing machine. In the figure, the face gear 1 before finish polishing is one in which a tooth portion 1a having a twist angle is formed by a conventional technique. The face gear 1 is finished by engaging a pinion-shaped grindstone 2 that is formed so as to mesh with the tooth portion 1a and in which abrasive grains (not shown) are electrodeposited on a screw-like portion 2a as shown in FIG. Polished.

  As shown in FIG. 2, the face gear 1 on which the tooth portion 1a before the finish polishing is formed is fixed so that the central axis O coincides with the lower base 3 of the general-purpose hobbing machine or NC hobbing machine. Then, a predetermined center pressure is applied in the downward direction of the figure by the support shaft 5 through the upper auxiliary center 4. On the other hand, the grindstone 2 is fixed to the hob shaft head (not shown) with the screw-like portion 2a facing the front side of the figure at the backward end of the hob shaft indicated by the retracted position A. As the general hobbing machine or NC hobbing machine, for example, a tool can be rotated synchronously with respect to a workpiece rotated at a desired speed, and can be arbitrarily moved in the X-axis, Y-axis, and Z-axis directions orthogonal to each other. Those configured and operated by numerical control can be used without any particular limitation.

  The face gear 1 set on the NC hobbing machine as described above is rotated at a predetermined number of rotations by the lower cradle 3, and the grindstone 2 that rotates in synchronization with the rotation has a predetermined dimension with respect to the central axis O. After moving to the point B on the Z-axis offset by L, the screw-shaped part 2a (FIG. 1) on which the abrasive grains are electrodeposited by moving in the direction of the arrow C on the Z-axis is shown in FIG. 2, the grindstone 2 is cut in the radial direction so as to mesh with the tooth portion 1 a not shown. Then, polishing is continued until the face gear 1 rotates by a predetermined angle of one round or more. Note that a plurality of grinding stones 2 having different abrasive grain sizes may be prepared and polished in a plurality of stages.

  As described above, the first embodiment uses the pinion-like grindstone 2 in which abrasive grains are electrodeposited on the screw-like portion 2a meshing with the tooth portion 1a having the twist angle of the face gear 1, and moves in the same manner as in actual meshing. Thus, the tooth portion 1a of the face gear 1 is finished and polished, so that there is no interference between the grindstone 2 and the face gear 1 as a workpiece. Therefore, finish polishing can be easily performed using a general-purpose hobbing machine or an NC hobbing machine. Further, since the polishing can be performed by the normal meshing operation of the face gear 1 and the pinion, the operation is simple and easy, and the efficiency is high and the yield is high.

  In order to improve the accuracy of the finished surface, the grinding wheel 2 is cut in the radial direction as described above, and then an axial feed (tangential feed) of the grinding stone 2 is added to rotate the grinding stone 2 by the axial feed. Polishing may be performed in the same manner until the face gear 1 rotates a predetermined amount with correction. Further, the cutting in the radial direction of the grindstone 2 and the feed in the axial direction of the grindstone 2 may be simultaneously applied (diagonal feed). In addition, at that time, the rotation correction for the axial feed of the grindstone 2 is added. In this case, the finished surface accuracy can be improved by a single finish polishing operation.

  In addition, although the thing similar to the pinion shown in FIG. 1 was used as the grindstone 2, it is not limited to this, For example, as shown in FIG. 3, it is a rod-like shape that can be fixed to a hob shaft head not shown. Abrasive grains are electrically connected to a thread-shaped processed portion 6a (not schematically shown in the drawing, which is shown in the drawing) formed so as to mesh with a tooth portion 1a having a twist angle of the face gear 1 formed at the end portion of the tool. It is good also as the grindstone 6 worn. Moreover, as what can be preferably used as an abrasive grain, general CBN abrasive grain, a diamond abrasive grain, etc. can be mentioned, for example. All of these are readily available.

  FIG. 4 is a cross-sectional view of an essential part showing an example in which the face gear finish-polished by a general-purpose hobbing machine as described above is used in an orthogonal shaft reduction gear, and FIG. It is. In FIG. 4, the finish-polished face gear 20 is engaged with a pinion 7 a that is toothed at the tip of the input shaft 7, and drives the output shaft 9 via the speed reduction mechanism 8. Further, in FIG. 5, the pinion 11 a that is cut at the tip of the rotating shaft 11 of the motor 10 is similarly meshed with the face gear 20 and drives the output shaft 9 via the speed reduction mechanism 9.

  Both the orthogonal shaft reduction gear and the orthogonal shaft geared motor configured as described above have reduced vibration and noise and less deceleration loss than those using a conventional orthogonal shaft reduction gear. In the first embodiment, the rotation axis of the face gear 20 and the input shaft 7 are offset from each other.

  As described above, according to the first embodiment, the grindstone 2 in which abrasive grains are electrodeposited on the screw-like portion 2a meshing with the face gear 1 when the tooth portion 1a of the face gear 1 having a torsion angle is finish-polished. Since the grinding is performed by synchronously rotating the face gear and the grinding wheel in a meshed state in which the cutting feed in the radial direction of the grinding wheel 2 is applied, the grinding stone 2 interferes with the tooth portion 1a of the face gear 1. There is no. For this reason, it becomes easy to process with high precision with a general-purpose processing machine without requiring a dedicated processing machine. Moreover, since it can be manufactured by a general-purpose machine, effects such as mass productivity and reduction in manufacturing cost can be obtained.

  DESCRIPTION OF SYMBOLS 1 Face gear, 1a Tooth part, 2 Grinding wheel, 2a Threaded part, 3 Lower support base, 4 Upper auxiliary center, 5 Support shaft, 6 Grinding wheel, 6a Processing part, 7 Input shaft, 7a Pinion, 8 Deceleration mechanism, 9 Output Shaft, 10 motor, 11 rotating shaft, 11a pinion, 20 finish-polished face gear, A retracted position, O center shaft.

Claims (3)

In a method of processing a tooth portion of the face gear by fixing a face gear having a twist angle meshing with a pinion to a cradle of a general-purpose hobbing machine or NC hobbing machine, the tooth portion of the face gear is connected to the general-purpose hobbing machine or the NC When grinding with a hobbing machine , a grindstone having a screw-like portion formed so as to mesh with the tooth portion of the face gear and having the same shape as the pinion and electrodeposited with abrasive grains on the surface is used. Polishing by synchronously rotating the face gear and the grindstone in a meshed state in which a direction cut feed is applied, and simultaneously giving a radial cut feed of the grindstone, and simultaneously giving an axial cut feed of the grindstone, A finish polishing method for a face gear, characterized in that an axial feed amount and rotation correction of the grinding wheel are given.   2. The face gear finish polishing method according to claim 1, wherein CBN abrasive grains are used as the abrasive grains.   2. The face gear finish polishing method according to claim 1, wherein diamond abrasive grains are used as the abrasive grains.

Images