JPS6140425Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a guided broach, and more specifically, a plurality of broach blades are grouped into one group, and this group is connected in multiple stages, and each group cuts the entire outer circumference. The broach is a broach that is transferred to a subsequent group having a larger outer diameter after the broach has finished, and the cutting edge portions and guide portions are alternately provided on the outer periphery of each of the plurality of broach blades described above, and the cutting edge of the preceding blade is further provided. This invention relates to a guided broach in which the center angular position of the shaft is shifted between the cutting edge portion of the cutting edge portion and the cutting edge portion of the succeeding blade.

First, a conventional broach will be explained with reference to FIGS. 1 and 2.

The broach 1 shown generally includes a shaft portion 3 and an introduction portion 5.
It consists of a cutting part 7 and a parallel part (not shown) following this, and after passing through the pilot hole 11 of the workpiece 9, it is mechanically or hydraulically driven and pulled out to the introduction part 5 side to cut holes and grooves of various shapes. This is a cutting tool that can be completed in one process.

The cutting section 7 usually has a large number of broach blades 13, and the connecting blade has a larger outer diameter than the preceding blade, and each blade performs the cutting work individually, and the last succeeding blade performs the desired cutting operation. Holes and grooves with the shape and dimensions of are completed.

In the conventional broach 1 in which all blades have cutting ability, even if both ends in the longitudinal direction are firmly fixed and tensioned, due to unevenness in the height of the workpiece 9, etc. This resulted in the inconvenience that the holes and grooves were machined out of alignment with the center of the hole 11.

That is, one of the round hole broaches as illustrated in Fig. 2.
Since each blade has cutting ability all around, it is easy to cause the above-mentioned misalignment especially in the case of a thin and long broach 1, and the broaching process, which is extremely effective for mass production, also causes many rejected products. They were losing that profit.

In addition, for square hole processing broaches, Tokuko Sho 53-21749
The issue has been published.

The technical content disclosed in this publication is that the machining hole is a square hole and the workpiece is a thin plate into which the rollers of a roller bearing retainer are inserted, so the first stage machining part is A cutting blade is provided that is guided by the tip guide section and processes the four opposing surfaces of the prepared hole without increasing the distance between the opposing surfaces, and the sixth stage processing section 12 is equipped with a cutting blade that processes the four opposing surfaces of the pilot hole without increasing the distance between the opposing surfaces. A cutting edge is provided around the entire circumference of the surface finish hole machining.

However, if the technique disclosed in this publication is used to machine a round hole as in the present application on a thick plate as shown in Figure 1, the problem of bending of the shaft and twisting in the direction of light loads, especially in the case of long and thin broaches, is disadvantageous. There is.

The broach 1 of the present invention was developed for the purpose of preventing the above-mentioned misalignment, and a preferred embodiment thereof is shown in FIG. 3 and subsequent figures, and the technical content of the invention will be explained in detail based on the figures.

Also, for the convenience of the following explanation, each blade 13 of the broach 1
The part that connects the two is named a connecting shaft part 15 to distinguish it from the shaft part 3 at the left end.

As shown in FIGS. 4, 5, and 6, the broach of this embodiment uses three broach blades 13 as one group to drill a round hole with an outer diameter slightly larger than the pilot hole described above.

The 1st, 2nd, and 3rd blades from the left of the broach blades 13 shown in Fig. 3 form one group, and the following 4, 5,
The sixth blade forms the second group and drills a round hole with a slightly larger outer diameter than the round hole machined in the first group.

The first broach blade 13 shown in FIG.
A guide part 17 having the same diameter as the pilot hole 11 is provided on the outer periphery, and a cutting edge part 19 protruding from the guide part 17 is provided at six points every 60 degrees.
This is an example in which there are several locations.

The second broach blade 13 shown in FIG.
A guide part 17 having the same diameter as the pilot hole 11 is provided on the outer periphery, and a cutting edge part 19 protrudes from the guide part 17.
However, the angular position at the center angle is shifted by 30 degrees so that the cutting edge portion 19 is located exactly in the center of the cutting portion 19 in FIG. 4.

The third broach blade 13 shown in FIG.
The first blade and the second blade cut grooves corresponding to a total of 12 protruding cutting blades.In addition to providing a cutting blade that cuts all of the remaining portion 17, the preceding broach blade It is provided with a guide portion 17 that comes into contact with the inner circumferential surface of the prepared hole 11 that has been cut.

As described above, when the 1st, 2nd, and 3rd blades in the first group finish machining, the second group of blades in the latter stage, which consists of the 4th, 5th, and 6th blades, move on to cutting. 4th broach blade 1
3 is in Fig. 4, and the fifth broach blade 13 is in Fig. 5.
The sixth broach blade 13 is the same as that shown in FIG.
The machining diameter gradually increases by stacking the stage, third stage, and subsequent stages, and the desired hole machining is completed by multiple stages of machining.

The broach according to the embodiment of the present invention described in detail above has a plurality of broach blades in one group, and a cutting edge part and a guide part are alternately provided on the outer periphery of each blade in the one group. All the blades, including those in the succeeding stages, are guided by the preceding round holes or grooves to proceed with machining.
Even if the thickness of the workpiece is thin, as long as it is thicker than the pitch of the broach blade, it will be effective in preventing misalignment throughout the entire house.

Although this example has been described using a round hole broach as an example,
I think there is no need to explain that the present invention can also be applied to broaches for holes or grooves having the following ring shapes.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional broach, FIG. 2 is a cross-sectional view taken along the arrow in FIG. 1, FIG. 3 is a partial side view of the broach according to the embodiment of the present invention, and FIG.
FIG. 5 is a cross-sectional view taken along the - arrow of FIG. 3, and FIG. 6 is a cross-sectional view taken along the negative arrow of FIG. 3. Explanation of the symbols representing the main parts of the drawing, 1...
Broach, 7...Cutting part, 13...Broach blade,
17... Guide section, 19... Cutting blade section.

Claims (1)

[Scope of utility model registration request] A plurality of broach blades 13 are provided with shafts that move relatively within the prepared hole 11 of the workpiece 9 from one end of the prepared hole 11 to the other end, and are used to cut the inner peripheral surface of the prepared hole 11. are arranged on the shaft at appropriate intervals,
A guide part that contacts the inner circumferential surface of the prepared hole 11 is provided around the first broach blade located at the forefront position in the relative movement direction of the shafts, and a part of the inner circumferential surface of the prepared hole 11 is cut. A plurality of cutting blades are arranged appropriately at equal intervals, and a guide part that contacts the inner peripheral surface of the pilot hole 11 is provided on the circumferential surface of an appropriate number of broach blades following the first broach blade. An appropriate number of cutting blades are provided at appropriate intervals to cut the center of the remaining inner peripheral surface of the pilot hole 11 left by the first broach blade, and on the peripheral surface of the subsequent rearmost broach blade, It is equipped with a cutting edge part that cuts all the remaining part of the inner circumferential surface of the prepared hole 11 left by the preceding broach blade, and a guide part that comes into contact with the inner circumferential surface of the prepared hole 11 cut by the preceding broach blade. A brooch with a guide featuring the following.