JP5648839B2 - Gear manufacturing method - Google Patents

Description

  The present invention uses a pinion-type cutter having a rotation axis inclined with respect to the rotation axis of a workpiece to be processed into a gear, and feeds the cutter in the direction of the teeth of the workpiece while rotating the cutter synchronously with the workpiece. The present invention relates to a gear manufacturing method using skiving.

  The skiving process will be described with reference to FIG. 1. The pinion-type cutter 1 having the rotation axis Ac inclined with respect to the rotation axis Aw of the work 10 is rotated synchronously with the work 10 while the teeth of the work 10 are rotated. This is a machining method in which a feed operation (here, a feed operation from above to below along the rotation axis Aw) is performed in the streak direction.

  In such skiving processing, cutting is performed by sliding generated by the rotational motion of the cutter and the workpiece, so that smooth cutting is possible compared to other processing methods in which the cutter is reciprocated and cut, High speed cutting can be easily realized by increasing the rotation speed of the cutter. Therefore, skiving is a particularly advantageous machining method when machining a gear having a large number of fine teeth, such as a wave gear.

  FIG. 6 is an explanatory diagram showing a cutting state immediately after the cutting edge 2 of the cutter 1 comes into contact with the workpiece 10 when an internal gear is manufactured from the workpiece 10 by a conventional gear manufacturing method using skiving. . Fig. a is a front view of the workpiece 10a as viewed from the front, Fig. b is a side view of the workpiece 10a as viewed from the side, Fig. c is a plan view of the workpiece 10 as viewed from above, and Fig. d is the cutting edge 2. It is a perspective view which shows the cutting area | region R by.

  Of the external surfaces constituting the cutting blade 2, the upper surface in the rotational direction of the cutter 1 is the upper surface 2a, the lower surface is the lower surface 2b, the lower surface in FIG. A surface to be configured is referred to as a front end surface 2d. As can be seen from each drawing in FIG. 6, the boundary corner portion between the upper surface 2 a and the bottom surface 2 c of the cutting blade 2 first contacts the workpiece 10 on the upper surface 10 b of the workpiece 10, and then the upper surface 2 a becomes the workpiece 10. Cutting is performed while maintaining the contact state. In the cutting region R, the contact surface between the upper surface 2a of the cutting blade 2 and the workpiece 10 is referred to as a upper cutting region Ru.

  According to the conventional gear manufacturing method using skiving, the cutting blade 2 first comes into contact with the upper surface 10b of the workpiece 10 while the cutter 1 is being fed downward from above. Since the upper surface 10b of the workpiece 10 is a surface perpendicular to the direction of the feed operation, all the reaction forces that the cutter 1 receives from the workpiece 10 at the time of contact act in a direction that prevents the feed operation, and the load acting on the cutting blade at the time of contact is large Become.

  Further, as apparent from FIG. 6 (d), for a while after the cutter 1 first contacts the workpiece 10, the workpiece 10 is cut in a form in which the upper cutting area Ru is enlarged, and the lower edge of the cutting blade 2. The surface 2b does not contact the workpiece 10. Therefore, since a load is generated only on the upper surface 2a of the cutting blade 2, the cutting blade 2 is likely to escape in the direction opposite to the rotation direction of the cutter 1, and there is a problem that the processing accuracy is deteriorated.

  In view of the above problems, in skiving processing, the load acting on the cutting blade when the cutter first contacts the workpiece in the cutter feeding operation is reduced, and the cutting blade escapes in the direction opposite to the rotation direction of the cutter. It is desirable to suppress the tendency.

The first characteristic means of the gear manufacturing method according to the present invention uses a pinion-type cutter having a rotation axis inclined with respect to the rotation axis of the workpiece to be processed into a gear, and while rotating the cutter synchronously with the workpiece, In the gear manufacturing method using skiving processing that feeds in the direction of the tooth trace of the workpiece, the corner portion of the workpiece that the cutter first contacts among the feeding operations of the cutter is chamfered before the skiving processing. processed and aft,
In the feeding operation of the cutter, the moving direction when the cutter first contacts the workpiece includes a direction component that is perpendicular to the rotation axis of the workpiece and approaches the processing surface of the workpiece .

  According to this characteristic means, when the cutter's cutting blade first comes into contact with the tapered surface of the workpiece formed by chamfering the corner portion, the vertical force out of the diagonal reaction force that the cutter receives from the workpiece at the time of contact. Since only the direction component acts in the direction that prevents the feeding operation, the load acting on the cutting blade at the time of contact is reduced.

  Furthermore, the area where the workpiece is cut immediately after the contact is reduced by the amount by which the corner portion of the workpiece is chamfered. In this way, the load acting on the cutting blade is reduced by reducing the cutting area itself, and the tendency of the cutting edge to escape in the direction opposite to the rotation direction of the cutter can be suppressed by reducing the good cutting area. it can.

In addition, if a workpiece with chamfered corners is used, the load acting on the cutting blade during contact between the cutter and the workpiece can be reduced, and the escape of the cutting blade in the direction opposite to the rotation direction of the cutter can be suppressed. It was. However, when the cutting blade comes into contact with the tapered surface in a direction parallel to the rotation axis of the workpiece, the cutting blade may slide along the tapered surface. If the cutter and workpiece shaft runout prevention functions are sufficient, such slipping will not cause a problem, but depending on the degree of shaft touch prevention function, the distance between the axes of the cutter and the workpiece will change, and the machining accuracy will deteriorate. There is a risk. Therefore, as in this feature means, when the cutter is operated so that the moving direction when the cutter first contacts the workpiece in the feeding operation of the cutter includes a direction component that is perpendicular to the workpiece rotation axis and approaches the workpiece processing surface. Since the cutter is pressed against the tapered surface at the time of contact between the cutter and the workpiece, the slip can be suppressed. As a result, it is possible to suppress deterioration in processing accuracy due to the sliding of the cutting blade.

The second characteristic means is that the cross-sectional shape of the cutter blade is a curve. Thereby, it is possible to perform processing with a cutting edge having a curved cross-sectional shape.

It is explanatory drawing which shows the outline | summary of the gear manufacturing method which concerns on embodiment of this invention. It is explanatory drawing which shows the cutting state immediately after a cutter contacts a workpiece | work. It is sectional drawing which shows the shape of the cutting blade of a cutter. It is sectional drawing which shows the shape of the cutting blade of the cutter in another embodiment. It is explanatory drawing which shows the movement locus | trajectory of the cutter in another embodiment. It is explanatory drawing which shows the cutting state immediately after a cutter contacts the workpiece | work in the conventional gear manufacturing method.

  Hereinafter, an embodiment in which a gear manufacturing method according to the present invention is applied to cutting of an internal gear will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing an outline of a gear manufacturing method according to an embodiment of the present invention using skiving. As described above, skiving is a feed operation in the direction of the teeth of the workpiece 10 while rotating the pinion cutter 1 having the rotation axis Ac inclined with respect to the rotation axis Aw of the workpiece 10 in synchronization with the workpiece 10 ( This is a processing method in which gearing is performed by performing a feed operation from above to below along the rotation axis Aw.

  The inner peripheral surface of the annular workpiece 10 is a processed surface 10a on which teeth are formed by skiving, and a corner corresponding to the boundary between the processed surface 10a and the upper surface 10b or the lower surface 10c is chamfered in advance. The tapered surface 10d is provided.

  FIG. 2 is an explanatory diagram showing a cutting state immediately after the cutter 1 contacts the workpiece 10. Fig. a is a front view of the workpiece 10a as viewed from the front, Fig. b is a side view of the workpiece 10a as viewed from the side, Fig. c is a plan view of the workpiece 10 as viewed from above, and Fig. d is the cutting edge 2. FIG. 7 is a perspective view showing a cutting region R according to FIG. 6 and corresponds to FIGS. 6a to 6d of FIG. Of the outer surfaces constituting the cutting edge 2, the upper surface in the rotational direction of the cutter 1 is the upper surface 2a, the lower surface is the lower surface 2b, and the lower surface is the bottom surface 2c in FIG. The surface constituting the cutting edge is referred to as a tip surface 2d.

  The cutting edge 2 of the cutter 1 first contacts the tapered surface 10d of the workpiece 10 formed by chamfering. Therefore, only the vertical component of the reaction force in the oblique direction that the cutter 1 receives from the workpiece 10 when the cutter 1 and the workpiece 10 are in contact acts in a direction that obstructs the feeding operation. The load acting on the cutting edge 2 at the time of contact is reduced by acting in the blocking direction.

  As apparent from the comparison between FIG. 2D and FIG. 6D, in this embodiment, the cutting region R in which the workpiece 10 is cut immediately after contact is equivalent to the amount of the chamfered corner of the workpiece 10. Get smaller. In particular, in the cutting region R, the upper cutting region Ru that is a contact surface between the upper surface 2a of the cutting blade 2 and the workpiece 10 is smaller than that in the case where the chamfering is not performed. Therefore, the load acting on the cutting edge 2 is reduced by reducing the cutting area R itself, and the cutting edge 2 tends to escape in the direction opposite to the rotation direction of the cutter 1 by reducing the good cutting area Ru. Can be suppressed.

  About the cross-sectional shape of the cutting blade 2, a square shape may be sufficient as shown in FIG. 3, and an external shape may consist of a curve as shown in FIG. Further, the shape is not limited to the shape shown in FIGS. 3 and 4, and other shapes can be adopted.

  As shown in FIG. 1, in the present embodiment, not only the corner corresponding to the boundary between the upper surface 10b and the processing surface 10a at which the cutter 1 first contacts the workpiece 10, but also the boundary between the lower surface 10c and the processing surface 10a. The corner portion corresponding to is chamfered to provide a tapered surface 10d.

  As can be seen from the opposite of FIG. 2D, if the corner corresponding to the boundary between the lower surface 10c and the machining surface 10a is also chamfered, the cutter 1 is fed downward from above and finally the cutter is cut. When 1 is separated from the workpiece 10, the cutting area is gradually reduced as compared with the case where chamfering is not performed. Therefore, load fluctuation when the cutter 1 is separated from the workpiece 10 can be suppressed. However, since the impact at the time of separation is smaller than the impact at the time of contact, chamfering the corner corresponding to the boundary between the lower surface 10c and the processed surface 10a is not an essential requirement.

[Another embodiment]
As shown in FIG. 5, in the feed operation of the cutter 1, the moving direction when the cutter 1 first contacts the workpiece 10 is a direction component that is perpendicular to the rotation axis Aw of the workpiece 10 and approaches the machining surface 10 a of the workpiece 10. Including it can be in an oblique direction.

  When using the workpiece 10 whose corners are chamfered, the cutting blade 2 slides along the tapered surface 10d when the cutting blade 2 contacts the tapered surface 10d in a direction parallel to the rotation axis Aw of the workpiece 10. There is. However, when the feed operation of the cutter 1 is performed as in the present embodiment, the cutting edge 2 is pressed against the tapered surface 10d when the cutter 1 and the workpiece 10 are in contact with each other, so that the above-described slip can be suppressed. . As a result, it is possible to suppress the deterioration of the processing accuracy due to the cutting blade 2 slipping.

  Further, if the feeding operation of the cutter 1 is performed in this way, the cutting area in which the workpiece 10 is cut immediately after the cutter 1 first contacts the workpiece 10 is reduced as in the case where the corner portion of the workpiece 10 is chamfered. An effect is obtained. Therefore, it is also possible to obtain an effect of reducing the load acting on the cutting blade 2 and suppressing the tendency of the cutting blade 2 to escape in the direction opposite to the rotation direction of the cutter 1 without performing chamfering on the workpiece 10. is there.

  In the present embodiment, when the cutter 1 first contacts the workpiece 10, not only is the cutter 1 fed in an oblique direction, but also when the cutter 1 is finally separated from the workpiece 10, it is perpendicular to the rotation axis Aw of the workpiece 10. Thus, the cutter 1 is fed in an oblique direction so as to include a direction component away from the processing surface 10a of the workpiece 10.

  If the cutter 1 is separated from the workpiece 10 in this way, the cutting area is gradually reduced, so that the impact when the cutter 1 is separated from the workpiece 10 can be suppressed. However, since the impact at the time of separation is smaller than the impact at the time of contact, it is not an essential requirement to send the cutter 1 in an oblique direction at the time of separation.

  The gear manufacturing method according to the present invention is particularly suitable for processing a wave gear having a large number of fine teeth, but is not limited thereto, and can also be applied to processing of an external gear or the like.

DESCRIPTION OF SYMBOLS 1 Cutter 2 Cutting edge 10 Workpiece 10a Work surface Aw Workpiece rotation axis Ac Cutter rotation axis

Claims (2)

Using a pinion-type cutter having a rotation axis inclined with respect to the rotation axis of the workpiece to be processed into a gear, and performing a skiving process in which the cutter is rotated in synchronization with the workpiece and fed in the direction of the tooth trace of the workpiece. In the gear manufacturing method used,
The corners of the workpiece in which the cutter of the feeding operation of the cutter first contacts, aft and chamfering before the skiving,
The gear manufacturing method in which the moving direction when the cutter first contacts the workpiece in the feeding operation of the cutter includes a direction component that is perpendicular to the rotation axis of the workpiece and approaches the processing surface of the workpiece . The gear manufacturing method according to claim 1, wherein a cross-sectional shape of the cutter blade is a curve .

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