JPH0698535B2 - Pinion vine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a pinion cutter used for gear cutting.

<Prior Art> A pinion cutter is a gear-shaped gear cutting tool, which is used to perform a generating gear cutting process by a rotary motion and a reciprocating motion that maintain a constant relationship with a work.

2 is a sectional view of the conventional pinion cutter, FIG. 3 is an enlarged view of FIG. 2 taken along arrow III, and FIG. 4 is a sectional view taken along line IV-IV of FIG. As shown in FIGS. 2 to 4, each blade portion 12 of the pinion cutter 11 has a tooth-shaped cutting blade 13, and a tooth tip surface 14 thereof.
A front clearance angle α and a lateral clearance angle β are formed on the left and right tooth surfaces 15, respectively, and a rake angle γ is formed on the rake surface 16. Conventionally, the tooth tip surface 14 that is the outer peripheral surface of the blade portion 12
Has a linear shape in a cross section cut in the tooth trace direction.

<Problems to be Solved by the Invention> In the pinion cutter 11, when the cutting edge 13 is worn, the rake face 12 is ground to scrape off the worn part to make a new cutting edge 13; Be seen. When this cutting grinding is performed, the tooth flank 14 and the left and right tooth flanks 15 are provided with the front clearance angle α and the lateral clearance angle β, so that the tooth length and the tooth thickness gradually decrease toward the rear part. . Therefore, in the subsequent blade cutting, the tooth thickness is reduced and the amount of cutting into the work is increased as much as the tooth is thin. However, in the conventional pinion cutter 11, since the tooth tip surface 14 of the blade portion 12 is linearly inclined along the tooth trace direction,
The cut amount to be increased corresponding to the tooth thickness reduction amount and the tooth length reduction amount do not match. As a result, when the work is an external gear, the root diameter becomes larger than the normal value, and when the work is an internal gear, it becomes smaller. That is, conventionally, there is a problem that every time the blade of the pinion cutter 11 is bladed, the root diameter of the workpiece machined by the pinion cutter 11 changes, which deteriorates the accuracy of the gear and the pinion cutter. It was to significantly limit the usable blade width of 11.

The present invention is to solve the problems in such a conventional pinion cutter, and provides a pinion cutter that can always cut a work having a constant root diameter even when bladed, thereby improving gear accuracy. The purpose is to extend the tool life.

<Means for Solving Problems> A pinion cutter according to the present invention for solving the above problems is a pinion cutter having a lateral clearance angle, in which a tooth tip surface of each blade portion has a tooth line depending on the lateral clearance angle. It is formed by curving along the direction, and the curving amount is set so that the depth of cut that increases along with the decrease in tooth thickness caused by cutting and the decrease in tooth height caused by the cutting match. It is characterized by being done. That is, in the case of processing an external gear, the addendum surface is curved in a convex shape, and in the case of processing an internal gear, the addendum surface is curved to a concave shape.

<Operation> The blade thickness reduces the tooth thickness, and the cutting depth of the cutter increases in accordance with the reduction amount, but the tooth thickness that causes the tooth tip surface to bend along the tooth trace direction is generated by the blade thickness. By setting so that the depth of cut that increases with the decrease in tooth depth and the amount of tooth height reduction that occurs due to the cutting are set to match, the position of the cutting edge cutting edge corresponds to the increase in the depth of cut of the cutter. It does not change, and as a result a proper work root diameter is always obtained.

<Examples> Examples of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. FIG. 1 (a) shows a pinion cutter for machining an external gear and FIG. 1 (b) shows a pinion cutter for machining an internal gear.

This pinion cutter 21 is, when processing an external gear, as shown in FIG. 1 (a), the tooth crest 22 thereof is convexly curved along the tooth trace direction, that is, the tooth trace direction. The outer shape of the blade portion 23 is formed so as to be curved in a convex shape in a cross section taken along. On the other hand, in the case of processing an internal gear, on the contrary, as shown in FIG. 1 (b), the tooth crest 22 is curved concavely along the tooth trace direction, that is, along the tooth trace direction. The outer shape of the blade portion 23 is formed so as to be curved in a concave shape in the cut section. These bending amounts correspond to the lateral clearance angle provided on the tooth surface of the blade portion 23, and the cutting amount to be increased according to the reduction of the tooth thickness caused by the blade attachment and the reduction of the tooth height produced by the blade attachment. It is given so as to match the quantity, and is calculated in advance. The tooth crest 22 of the pinion cutter 21 can be processed by, for example, an NC grinder equipped with a shaping grindstone having a required shape.

Thus, according to the pinion cutter 21, the tooth thickness is reduced by the blade attachment, and as a result, even if the cutting amount is increased according to the reduction amount, the amount of curvature of the tooth tip surface is increased. The amount of cutting is the same as the amount of tooth height reduction caused by blade cutting, so the position of the cutting edge cutting edge with respect to the workpiece does not change in correspondence with the increased cutting depth of the cutter. , It is possible to always obtain a proper work root diameter.

<Effects of the Invention> As described above with reference to examples, according to the present invention,
Even when the tooth thickness is reduced by cutting with a blade, it is possible to cut a workpiece with a constant root diameter at all times, which improves gear accuracy and increases the cutter blade width. It is possible to extend the tool life.

[Brief description of drawings]

FIG. 1 relates to an embodiment of the present invention. FIG. 1A shows a pinion cutter for machining an external gear, FIG. 1B shows a pinion cutter for machining an internal gear, and FIG. 2 shows a conventional pinion cutter. FIG. 3 is a sectional view, FIG. 3 is an enlarged view taken in the direction of arrow III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG. In the drawing, 21 is a pinion cutter, 22 is a tooth tip surface, and 23 is a blade.

Claims (1)

[Claims] 1. A pinion cutter having a lateral clearance angle, wherein the tooth tip surface of each blade portion is curved along the tooth trace direction in accordance with the lateral clearance angle, and the curvature amount is generated by the toothing. A pinion cutter characterized in that the depth of cut that increases with a decrease in thickness and the amount of decrease in tooth height caused by cutting the blade are set to match.