JPH01188219A - Broach tool - Google Patents

Abstract

PURPOSE:To prevent the jamming of chips and the deterioration of machining accuracy, and to make the manufacturing cost of a broach tool inexpensive by cutting off a chip space between adjacent cutting edges on both sides of the tool to form the face of the cutting edge into a shape having a proper curvature. CONSTITUTION:A chip space 6 in an usual broach tool of a broach body 1 is diagonally cut from the top 7 of an adjacent cutting edge to its base 8 to form the face 10 of the cutting edge 2 into an arc-shape having a proper curvature or a polygon-shape. Consequently, the capacity of a chip pocket 5 can be sufficiently insured, and moreover the cut off amount of the chip space 6 is decreased as the base 8 having the highest stress is approached to prevent the occurrence of a problem on the strength of the cutting edge. Thus the occurrence of the jamming of chips can be prevented, and moreover trouble such as the deterioration of machining accuracy due to an increase caused by the jamming of chips in cutting force can be eliminated. In addition, an usual broach tool can be altered in a simple manner, and the manufacturing cost of the broach tool can be also made inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a proching tool used during broaching with a machine tool.

[Conventional technology]

When mass producing a small variety of workpieces, if it is necessary to process the workpieces into special shapes such as spline holes, T-grooves, or Christmas tree shapes at the roots of turbine blades,
Broaching using a broach as a cutting tool is adopted.

As is well known, a broach is a rod-shaped body with a rough cutting edge to a finishing cutting edge formed at one-foot intervals in a shape corresponding to the processing shape. By moving the and brooch relative to each other,
Processing can be performed extremely quickly and with high precision.

FIG. 8 shows the processing situation of such broaching. As shown in the figure, between adjacent cutting blades 2 formed at regular intervals on the broach body 1, there are blade grooves (chip pockets) for storing chips 4 of the workpiece 3 scraped off by these cutting blades 2. The cutting edge on the finishing cutting edge side (on the right side in the figure) is set to be larger so that the depth of cut of the valley cutting edge 2 into the workpiece 3 is equal. During machining with this broach, the chips 4'' are not discharged outside the blade groove 5 in principle, so it is necessary to set the volume of the blade groove 5 appropriately according to the depth of cut of each cutting blade 2.

[Problem to be solved by the invention]

By the way, in a conventional broach tool, which has cutting edges on both sides of the tool, such as the one used to process the Christmas tree shape of the root of a turbine blade as shown in FIG. It is difficult to secure a sufficient volume of the chip pocket, and as shown in FIG. 10, there is a problem in that the chip pocket becomes insufficient in capacity and the problem of chip clogging is likely to occur.

If the volume of the blade groove 5 of the broach is inappropriate, especially if the volume of the blade groove 5 is too small, the chips 4 will not be able to fit into the inner cutting of the blade groove, resulting in a significant increase in cutting resistance and cutting. This may cause damage to the blade.

In order to prevent such problems, it is necessary to reduce the depth of cut of the blade or to greatly expand the volume of the blade groove. - If the depth of cut of the blade is made smaller, the number of cutting edges will increase accordingly and the broach tool will become longer, causing an increase in costs in terms of machining efficiency, tool price, etc.

On the other hand, with a broach tool that has cutting edges on both sides, such as those used to process the Christmas tree shape, it is geometrical to ensure that the volume of the blade groove is the same as the conventional blade groove shape and the amount necessary to prevent chips. It is often scientifically difficult. The present invention improves a broach tool that has cutting edges on both sides of the tool and cannot secure a sufficient blade groove volume due to the narrow spacing between the opposing cutting edges on both sides, and solves the above-mentioned problems. This is to solve the problem.

[Means to solve the problem]

For this reason, the broach tool of the present invention has cutting edges on both sides, in which the blade groove 6 portion between opposing adjacent cutting blades on both sides is removed, and the rake face of the cutting blade is It is characterized by being configured in an arcuate or polygonal shape with an appropriate curvature in the direction of force of the tool's grip.

[Effect]

The broaching tool of the present invention described above can be made by cutting off the grooves between the opposing cutting edges on both sides of the tool to the extent that the strength of the tool is not affected. By configuring the rake face shape of the cutting blade in an arcuate or polygonal shape, the chips are curled in a small manner as in the conventional method, and the chips can be easily discharged, and it is possible to prevent chips from getting stuck in the blade groove.

If the cutting edge rake face shape is not arcuate or polygonal, but only the blade groove is scraped off, the volume of the chip pocket will increase, but since only the straight straight portion of the rake face will remain, the chips will not curl and will not curl. It is difficult to excrete, which has the opposite effect.

〔Example〕

A broaching tool according to a first embodiment of the present invention is shown in FIGS. 1 and 2 below. The blade sewing part 6 of the conventional broach tool of the broach body 1 is separated from the top 7 of the adjacent front blade,
Scrape diagonally to the base 8 of the blade. As a result, a sufficient capacity of the chip pocket 5 can be ensured, and problems regarding strength do not occur because the amount of scraping is reduced toward the root portion 8 of the blade where the stress is highest.

Furthermore, the rake face shape 10 has a curvature in the cutting direction of the broach as shown in FIG. Curl small through the hair.

In addition, in order to curl the chips 4, the rake face shape 10 may be curved with a certain curvature, or may be polygonal as shown in FIG.

Next, a second embodiment of the present invention is shown in FIGS. 4 and 5. In this example, the blade groove portion 6 is cut perpendicularly to the longitudinal direction of the tool, and the same effect as in FIG. 1 can be obtained. From the viewpoint of strength, it is desirable that the blade groove to be removed be less than or equal to the Z of the conventional blade groove.

Furthermore, the present invention has a third embodiment shown in FIG. 6.7,
The removed portion of the blade groove may be cut obliquely from the top 7 of the front blade to the middle of the blade instead of the root 8. That is,
For example, in the case of a broach that is used to make a Christmas tree shape, where the blade becomes thicker toward the root of the blade, the chip pocket volume 5 may be sufficient even if the conventional blade groove shape 6 is maintained near the root of the blade. Yes, in that case there is no need to remove it. Therefore, we cut the blade groove only in the problem area.
This example is the original one. (If you look at FIG. 7(B), which shows the BB cross section of FIG. 6, the chip pocket shape is the same as the conventional one.) Several embodiments of the present invention have been described above, but the present invention The present invention is not limited to these embodiments, and various design changes may be made within the scope of the technical concept of the present invention.

〔Effect of the invention〕

As described above, the broaching tool of the present invention provides the following effects.

(1) The groove between adjacent cutting edges has been shaved off, so there is sufficient capacity for the chip pocket, and the rake face of the cutting edge is arcuate or polygonal, making it easier to curl generated chips than before. This eliminates the generation of chips.

(2) As a result, troubles such as damage to the broach due to chip clogging and deterioration of machining accuracy due to increased cutting force caused by chip clogging are eliminated.

(3) Conventional broaching tools can be easily modified, and the cost is low.

[Brief explanation of the drawing]

1 is a side view and a front view of a first embodiment of the broaching tool of the present invention, and FIG. 2 is taken along the line A-A in FIG. B-B, C-C, D-D various side views, Fig. 3 is another embodiment in which the rake face is polygonal, Fig. 4 is a side view of the $2 embodiment of the present invention, Fig. 5 6 is a side view of the third embodiment of the present invention, and FIG. 7 is a sectional view taken along line AA in the same figure.
13-B each cross-sectional view, and the sword loe shape diagram with the broach tool of the 8th same cross-sectional view are shown. l...Broach body, 2...Cutting blade, 3...
Workpiece, 4... Chips, 5... Chip pocket, 6... Blade. A1 3rd grade 84 drawings

Claims (1)

[Claims] 1. In a broach tool that has cutting edges on both sides, the grooves between the opposing adjacent cutting edges on both sides are ground down, and the rake face of the cutting edge is shaped into an arc with an appropriate curvature in the longitudinal direction of the tool. Or a broach tool characterized by having a polygonal shape.