JPS6130322A - Tool for finishing external gear - Google Patents

Abstract

PURPOSE:To enable the formation of a finished external gear of high reliability and accuracy, by providing numerous cutting teeth each having a plurality of cutting edges extending in the directions of the heights of the teeth and juxtaposed in the directions of the faces of the teeth, so that the teeth are disposed as an internal gear having openings corresponding to the outline of the external gear roughly processed. CONSTITUTION:The body 1 of a tool is integrally provided with numerous cutting teeth 2, 2 extending on the inside surface of the tool body in the direction of its width and having their tops oriented toward the center of the tool. The thickness of each of the cutting teeth 2, 2 is decreased toward the top. The cross-sectional form of each of openings 3, 3 of the tool corresponds to that of each tooth of a gear to be finished by the tool. When the tool is to be used, it is secured on a base having a takeout hole and located on a press, so that the tool's insertion side toward which the width of each cutting tooth 2 is decreased is placed as the upside. The roughly processed gear is pressed down into the gear insertion opening 1a of the tool so that the teeth of the gear are sequentially cut by serration edges 5a-5d as the gear is moved through the tool. The teeth of the gear are thus accurately finished to the same form as the opening between the serration edges 5d on the takeout side of the tool.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an external gear finishing tool for precision finishing a rough-machined external gear after gear cutting.

Conventionally, so-called shaving processing, which utilizes the engagement between a rough-finished external gear and a shaving cutter shaped like an external gear, has been often used for finishing external gears.

However, in general, in shaving processing, when conditions change, such as when the shaving cutter diameter changes, the workpiece tooth profile changes, and even if the shaving cutter tooth profile curve (tool curve) is a regular involute, the workpiece tooth profile does not become a regular inpolyne. When attempting to raise the tooth profile accuracy of a finished gear beyond a certain level due to unstable elements that are difficult to analyze, a trial check is required, which poses the problem of low accuracy reliability.

In view of the above-mentioned conventional problems, the present invention aims to provide an external gear finishing tool that can obtain highly reliable and highly accurate finished gears without the need for trial checking in place of a shaving cutter. The gist of the structure is that it is equipped with a large number of cutting teeth in the shape of an internal gear with a space that matches the external shape of the roughing gear, and each of the cutting teeth has a large number of cutting edges along the tooth height direction in the tooth width direction. This gear finishing tool consists of multiple external gear finishing tools, and by pushing the entire rough-machined workpiece, leaving a finishing allowance, into this gear finishing tool and finishing the gold teeth at the same time, the cutter accuracy remains unchanged on the workpiece. This is intended to provide reliability in terms of accuracy, which is not expressed as finishing accuracy, but is commensurate with cutter accuracy.

Next, an example of implementation of the present invention will be described with reference to the drawings. In the figure, 1 is the tool body. This tool body is formed into a cylindrical shape, and has a large number of cutting teeth 2, 2...
is integrally molded with the top of the tooth facing toward the center. Each cutting tooth 2, 2... has a keto shape with 9 'Jcm' on the tooth top side,
Spaces 3, 3... between these cutting teeth 2, 2...
The radial cross-sectional shape of is the tooth shape of the gear to be finished. These tooth-shaped spaces 3, 3, . . . are annularly provided along the inner surface of the tool body, and a gear insertion space 1a having a gear-shaped cross section as a whole is formed in the tool body 1.

Further, as shown in Fig. 2, each cutting tooth 2 is formed in a tapered shape along the axial direction of the tool body, with the tooth width being smaller on the insertion side and larger on the ejection side, and both sides of the tool body in the circumferential direction. A plurality of serration grooves 4, 4... are formed in the tooth height direction.
are formed, and serration edges 5a, 5b, .

Each of these serration edges is formed to become larger as it reaches the discharge side 5d according to the taper of the cutting tooth 2, and each of the serration edges 5d, 5d,
5d: The workpiece is finished into a tooth profile with the same size as the tooth profile cross-sectional space to be formed between.

When using an external gear finishing tool configured in this manner, for example, a press machine is used to fix the tool body 1 on a base 7 with a punched hole 6 with the insertion side of the cutting teeth 2 having a smaller tooth width facing upward. Then, the roughly machined workpiece 10 is pushed into the gear insertion space la from above. As a result, while the workpiece 10 passes through the tool, the tooth surface is sequentially cut by each of the serration edges 5a to 5d, and finally each tooth of the workpiece 10 is precisely cut into the shape of the space between the serration edges 256 on the discharge side. It will be finished.

The external gear finishing tool of the present invention is constructed as described above, and is equipped with a large number of cutting teeth in the shape of an internal gear having a space that matches the external shape of the rough processing gear, and each of the cutting teeth has a large number of cutting teeth along the tooth height direction. The tool has multiple cutting edges in the tooth width direction, and by pushing the rough-machined workpiece through the internal space of the tool, the workpiece can be finished to match the inner shape of the tool.
Since the accuracy of the tool directly corresponds to the accuracy of the finished gear, there is no need for a trial like when finishing with a cutter on a shaving machine. be exposed.

In addition, since the processing method is forced pushing through, the spur gear can be easily finished with high precision using a commonly used simple press machine rather than a dedicated machine.

[Brief explanation of the drawing]

The drawings show an example of the implementation of the present invention, and FIG. 1 shows the main parts of the tool according to the present invention. 2 is an enlarged sectional view of the cutting tooth, and FIG. 3 is a vertical sectional view of the cutting tooth in use. In the figure, 1 is the tool body, 2 is the cutting tooth, and 4 is the serration groove. 5a to 5d are serration edges, and 10 is a workpiece.

Claims (1)

[Claims] An external gear that has many cutting surfaces in the shape of an internal gear with a space that matches the external shape of the roughing gear, and each of the cutting teeth has a number of cutting edges along the tooth height direction in the tooth width direction. Finishing tools.