JP2001287113A - Combination end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combination end mill capable of machining a stepped hole with a large hole next to a small hole in one process to adjust a machining depth of the small hole at that time and to separate it into an end mill for machining the small hole and an end mill for machining the large hole for exchanging each of them independently. SOLUTION: A shank part 1B of the small end mill 1 is engaged concentrically and movably in an axial direction with a mounting hole 2C formed along the axial direction of the large end mill 2 and adjusted axially in position for being fixed detachably on a shank part 2B of the large end mill 2 such that a cutting edge part 1A of the small end mill 1 adapted to machine the small hole A protrudes concentrically by a desired length from a tip of a cutting edge part 2A of the large end mill 2 adapted to machine the large hole B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combination end mill, and more particularly to a combination end mill for cutting a stepped hole in which a large diameter hole is continuous with a small diameter hole.

[0002]

2. Description of the Related Art Conventionally, when a stepped hole in which a large-diameter hole is continuous with a small-diameter hole, such as a pilot hole of a bolt fastening hole with a counterbore hole, is cut into a work, it is conventionally described in Japanese Utility Model Laid-Open No. 5-37411. Solid end mill,
A boring bite bar as described in Japanese Patent Application No. 10003 is used.

[0003] The solid end mill is a cutting tool having an outer peripheral edge and a bottom edge formed at a tip end of a shank portion. By using two tools corresponding to the small diameter hole and the large diameter hole, the solid end mill is formed in two steps. Stepped holes can be machined. On the other hand, the boring bar is a first tool having a small turning radius welded and fixed to the lower end of the bar,
A cutting tool having a second turning tool with a large turning radius welded and fixed to a peripheral surface of the bar above the cutting tool, wherein the stepped hole can be cut in one step.

[0004]

When cutting a stepped hole using the solid end mill,
Since two steps of cutting a small diameter hole with a solid end mill for a small diameter hole and then cutting a large diameter hole with a solid end mill for a large diameter are required, there is a problem that work efficiency is poor.

On the other hand, when a stepped hole is cut using the boring bar, the first bite and the second bite are cut.
Since the cutting tool is fixed to the bar by welding and the interval between the two cannot be adjusted in the axial direction of the bar, there is a problem that the working depth of the small diameter hole cannot be adjusted. Further, if any of the first byte and the second byte is worn out or broken, the entire boring bar must be replaced, resulting in an increase in cost.

Accordingly, the present invention provides an end mill which can cut a stepped hole in which a large-diameter hole and a small-diameter hole are continuous in a single step, and can adjust the processing depth of the small-diameter hole at that time, and cut the small-diameter hole. It is an object of the present invention to provide a combined end mill that can be separated into end mills for cutting large-diameter holes and can be replaced separately.

[0007]

As a means for solving the above-mentioned problems, a combined end mill according to the present invention is an end mill for cutting a stepped hole in which a large-diameter hole is continuous with a small-diameter hole. A small-diameter end mill for cutting
A large-diameter end mill for cutting the large-diameter hole, and a shank portion of the small-diameter end mill such that the cutting blade portion of the small-diameter end mill projects concentrically from the tip of the cutting blade portion of the large-diameter end mill by a desired length. Is axially movably fitted to the mounting hole provided along the axial direction of the large-diameter end mill, and is adjustable in the axial direction with respect to the shank portion of the large-diameter end mill to be removable. Characterized by being fixed to.

[0008] In the combination end mill of the present invention, the cutting blade portion of the small-diameter end mill, which protrudes concentrically from the tip of the cutting blade portion of the large-diameter end mill, cuts the small-diameter hole, and continuously cuts the large-diameter end mill. When the blade portion cuts the large-diameter hole, a stepped hole in which the large-diameter hole is continuous with the small-diameter hole is cut in one step. At this time, the working depth of the small-diameter hole is adjusted by adjusting the position of the shank of the small-diameter end mill with respect to the shank of the large-diameter end mill in the axial direction. Then, when the cutting blade portion is worn or broken, it is separated into a small-diameter end mill and a large-diameter end mill, and each is separately replaced.

In the combination end mill according to the present invention, a stopper bolt abutting on the end face of the shank portion of the small diameter end mill fitted into the mounting hole of the large diameter end mill can freely advance and retreat in the axial direction from the end face of the shank portion of the large diameter end mill. When it is screwed in, the stopper bolt is advanced and retracted with respect to the shank of the large-diameter end mill, whereby the shank of the small-diameter end mill is accurately adjusted in the axial direction with respect to the shank of the large-diameter end mill, and the small-diameter hole is formed. Is preferred because the working depth of the steel is accurately adjusted.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a combination end mill according to the present invention will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 is an explanatory view of a usage state of a combination end mill according to one embodiment, FIG. 2 is a side view showing a large-diameter end mill of the combination end mill according to one embodiment, and FIG. Bottom view of combination end mill shown in FIG. 2, FIG.
Is a side view showing the large-diameter end mill shown in FIG. 2 with a part cut away, and FIG. 5 is a bottom view of the large-diameter end mill shown in FIG.

As shown in FIG. 1, a combined end mill according to one embodiment is an end mill for cutting a stepped hole C in which a large-diameter hole B is continuous with a small-diameter hole A into a work W, and the small-diameter hole A is A small-diameter end mill 1 for cutting and a large-diameter end mill 2 for cutting a large-diameter hole B are provided. The small-diameter end mill 1 is fitted to the large-diameter end mill 2 such that the cutting edge 1A of the small-diameter end mill 1 projects concentrically from the tip of the cutting edge 2A of the large-diameter end mill 2 by a desired length. It is configured in combination.

As shown in FIGS. 2 and 4, the large diameter end mill 2 has a shank portion 1 of the small diameter end mill 1.
A mounting hole 2C into which B is fitted and mounted is formed. The mounting hole 2C is a straight hole extending from the distal end surface of the cutting blade portion 2A of the large diameter end mill 2 to near the center of the shank portion 2B, and is formed concentrically with the shank portion 2B. The shank portion 1B of the large-diameter end mill 2 is detachably fixed to the shank portion 1B of the small-diameter end mill 1 fitted into the mounting hole 2C by a set screw (not shown).
Are formed with a pair of upper and lower setscrew holes 2D, 2D penetrating from the peripheral surface to the mounting hole 2C.

The shank portion 2B of the large-diameter end mill 2 has a mounting hole 2C extending axially from an end face thereof.
A female screw hole 2E is formed through the female screw hole 2E.
, A stopper bolt 3 is screwed forward and backward freely. When the tip of the stopper bolt 3 abuts on the end face of the shank 1B of the small-diameter end mill 1 fitted into the mounting hole 2C, the shank 1B of the small-diameter end mill 1 is turned into the shank 2B of the large-diameter end mill 2. It is configured to be positioned in the axial direction with respect to.

The stopper bolt 3 has a nut 4 pressed against the end face of the shank 2B of the large diameter end mill 2.
Is screwed. The nut 4 cooperates with the shank portion 2B to perform the function of a double nut, so that the stopper bolt 3 can be fixed at a predetermined advance / retreat position.

As shown in FIGS. 2 and 3, the cutting edge 2A of the large-diameter end mill 2 is provided with a pair of tips 2A1 and 2A1 each having an outer peripheral cutting edge and a bottom cutting edge. The pair of chips 2A1 and 2A1 are arranged at point-symmetric positions with the center of the cutting blade 2A as a symmetric point, and the cutting surfaces 2A2 and 2A2 are located on the diameter line of the cutting blade 2A. . And this cutting edge surface 2A2,
Chip discharge grooves 2A3 and 2A3 that are continuous with 2A2 are formed in the cutting blade 2A.

On the other hand, the cutting blade 1 of the small-diameter end mill 1
4A and 5A, a pair of outer peripheral cutting edges 1A1 spirally extending in the axial direction, a pair of bottom cutting edges 1A2 arranged on a diameter line at the tip thereof, and the outer peripheral cutting edge 1A2. A pair of swarf discharge grooves 1A spirally extending along the blade 1A1
3 are formed.

The combined end mill according to the embodiment having the above-described configuration is composed of a large-diameter end mill 2 and a small-diameter end mill 1.
Are used in the combined state shown in FIG. Therefore, a description will be given of a combination operation for fitting and fixing the small-diameter end mill 1 to the large-diameter end mill 2.

First, as shown in FIG. 4, the shank portion 1B of the small-diameter end mill 1 is inserted into the mounting hole 2C of the large-diameter end mill 2, and its end face abuts against the front end face of the stopper bolt 3. Next, the nut 4 is loosened and the stopper bolt 3 is advanced and retracted in the axial direction of the shank portion 2B of the large-diameter end mill 2, and the cutting blade portion 1A of the small-diameter end mill 1 protruding from the tip end surface of the cutting blade portion 2A of the large-diameter end mill 2. Adjust the amount of protrusion. Then, the nut 4 is screwed and pressed against the end face of the shank portion 2B, and the stopper bolt 3 is positioned and fixed in the reciprocating direction by the double nut function.

Next, the small-diameter end mill 1 and the large-diameter end mill 2 are relatively rotated while maintaining the state in which the end face of the shank portion 1B of the small-diameter end mill 1 abuts against the distal end surface of the stopper bolt 3, and the small-diameter end mill is rotated. 1 cutting blade 1A
And the cutting blade 2A of the large-diameter end mill 2 are aligned in the rotation direction. That is, the chip discharge groove 1A of the cutting blade 1A
3, 1A3 and chip discharge groove 2A3, 2A3 of cutting blade 2A
Are aligned so that and are continuous. In this state, a set screw (not shown) is inserted into a pair of upper and lower set screw holes 2D, 2D provided in the shank portion 2B of the large diameter end mill 2.
And fix the shank portion 1B of the small-diameter end mill 1 to the shank portion 2B of the large-diameter end mill 2.

As described above, in the combination end mill according to the embodiment in which the small-diameter end mill 1 is fitted and fixed to the large-diameter end mill 2, as shown in FIG. It is used by being attached to. In this use state, the cutting blade 1A of the small-diameter end mill 1 projecting concentrically from the tip of the cutting blade 2A of the large-diameter end mill 2 cuts the small-diameter hole A in the work W, and continuously cuts it. Cutting edge 2A of large diameter end mill 2
Cuts the large-diameter hole B. That is, the combined end mill of one embodiment cuts the stepped hole C in which the large diameter hole B is continuous with the small diameter hole A via the step portion B1 in one step.

Here, as described above, the combination end mill according to the embodiment is configured such that the stopper bolt 3 is axially moved forward and backward with respect to the shank portion 2B of the large-diameter end mill 2 so that the cutting blade of the large-diameter end mill 2 is formed. The protrusion amount of the cutting blade portion 1A of the small-diameter end mill 1 protruding from the distal end surface of the portion 2A can be accurately adjusted, and as a result, the processing depth of the small-diameter hole A can be accurately adjusted.

Further, in the combination end mill of one embodiment, when the cutting blade portion 1A of the small diameter end mill 1 or the cutting blade portion 2A of the large diameter end mill 2 is worn or broken,
The small-diameter end mill 1 and the large-diameter end mill 2 can be separated and replaced separately.

In the combination end mill of the present invention, the shank portion 2B of the large diameter end mill 2 is not limited to a straight shank, but may be an appropriate taper shank.

[0024]

As described above, according to the combination end mill of the present invention, the cutting edge of the small-diameter end mill that projects concentrically from the tip of the cutting edge of the large-diameter end mill cuts the small-diameter hole, By successively cutting the large-diameter hole by the cutting blade portion of the large-diameter end mill, a stepped hole in which the large-diameter hole is continuous with the small-diameter hole can be cut in one step. At this time, the processing depth of the small diameter hole can be adjusted by adjusting the position of the shank portion of the small diameter end mill with respect to the shank portion of the large diameter end mill in the axial direction. When the cutting blade portion is worn or broken, it can be separated into a small-diameter end mill and a large-diameter end mill and can be separately replaced.

In the combined end mill according to the present invention, the stopper bolt, which is fitted into the mounting hole of the large-diameter end mill and abuts on the end face of the shank portion of the small-diameter end mill, is freely movable in the axial direction from the end face of the shank portion of the large-diameter end mill. When the stopper bolt is moved forward and backward with respect to the shank of the large-diameter end mill, the shank of the small-diameter end mill can be accurately adjusted in the axial direction with respect to the shank of the large-diameter end mill. The working depth of the small diameter hole can be adjusted accurately.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a usage state of a combination end mill according to an embodiment of the present invention.

FIG. 2 is a side view showing a large-diameter end mill of the combination end mill according to the embodiment, partially cut away.

FIG. 3 is a bottom view of the combination end mill shown in FIG. 2;

FIG. 4 is a side view showing the large diameter end mill shown in FIG.

FIG. 5 is a bottom view of the large-diameter end mill shown in FIG.

FIG. 6 is a partially cutaway side view of a large-diameter end mill of a combination end mill according to another embodiment of the present invention.

FIG. 7 is a bottom view of the combination end mill shown in FIG. 6;

[Explanation of symbols]

 1: Small diameter end mill 1A: Cutting blade part 1B: Shank part 2: Large diameter end mill 2A: Cutting blade part 2B: Shank part 2C: Mounting hole 2D: Set screw hole 2E: Female screw hole 3: Stopper bolt 4: Nut A: Small diameter Hole B: Large diameter hole B1: Step part C: Stepped hole D: Chuck W: Work

Claims (2)

[Claims] 1. An end mill for cutting a stepped hole in which a large-diameter hole is continuous with a small-diameter hole, comprising: a small-diameter end mill for cutting the small-diameter hole; and a large-diameter end mill for cutting the large-diameter hole. The shank portion of the small-diameter end mill was provided along the axial direction of the large-diameter end mill so that the cutting edge portion of the small-diameter end mill protruded a desired length concentrically from the tip of the cutting blade portion of the large-diameter end mill. A combined end mill, wherein the combined end mill is fitted coaxially with the mounting hole so as to be movable in the axial direction, and is adjusted in the axial direction with respect to the shank portion of the large-diameter end mill and is detachably fixed. 2. A stopper bolt which abuts an end face of a shank portion of the small-diameter end mill fitted in a mounting hole of the large-diameter end mill is screwed into the large-diameter end mill so as to be able to advance and retreat in an axial direction from an end face of the shank portion. The combination end mill according to claim 1, wherein: