JPH10315026A - Pulling-out counterboring head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To counterbore a slender through hole with high accuracy by arranging a connecting hole fixed by being connected to a shank in a small column part, and boring a cutting edge fixing hole in a connecting part of a large column part and the small column part. SOLUTION: A work in which a prepared hole is bored is fixed to a main spindle of a machine tool, and a shank fixed to a table is inserted into the prepared hole of the work. A small column part 2 of a main body is screwed in the tip of its shank, and they are integrally joined together. Next, the main spindle is rotated, and the main body is sent so as to be relatively pulled out of the work. According to this, a small column part 2 having an inside diameter smaller than the prepared hole of the work enters the prepared hole. Then, a cutting edge 8 projecting from a lower end peripheral surface of a large column part 2 larger than the prepared hole of the work, cuts it by coming into contact with the peripheral edge of the prepared hole of the rotating work, and expands the prepared hole to a finishing hole having a prescribed inside diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a counter boring head suitable for processing an inner diameter of an elongated through hole.

[0002]

2. Description of the Related Art Conventional counter boring heads are:
It is composed of a main body with a cutting edge at the front end and a shank extending rearward from the main body, and when counter-boring an elongated through hole such as a shaft hole of a roll, the elongated shank buckles and bends due to compressive force, There was a problem that processing accuracy was reduced.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a boring head capable of counterboring an elongated through hole with high precision. It is in.

[0004]

In order to achieve the above object, the present invention employs a method in which a boring head body is coaxially integrated with a small cylindrical portion having a diameter smaller than a prepared hole of a work. It is formed from a large cylindrical portion that is larger in diameter than the connected work's pilot hole but smaller in diameter than the finishing hole, and has a connecting hole that is fixed to the small cylindrical portion by connecting it to the shank. A cutting blade fixing hole is formed in the connecting portion of the above, a cutting blade protruding radially from the peripheral surface of the large cylindrical portion is fixed therein, and a chip discharge path which passes from the cutting blade fixing hole to the connecting hole is formed.

When the shank has a thread at the tip,
It is desirable to provide a female screw in the connection hole and connect and fix it to the shank. The fixing hole for the cutting blade is formed in a cylindrical shape oblique to the axis so that the inside is away from the small column in the axial direction, and a cylindrical base that fits into the fixing hole for the cutting blade is attached to the cutting blade. It is fixed to the large cylinder with two or more setscrews screwed in from the circumference of the cylinder, and further, an adjustment screw hole is cut out from the inner bottom of the cutting blade fixing hole to the circumference of the large cylinder. It is preferable to adjust the length of the cutting blade protruding from the peripheral surface of the large cylindrical portion by screwing an adjusting screw into the screw.

When a guide groove is formed on the peripheral surface of the large cylindrical portion for fitting the guide, and the guide is detachably fixed to the guide groove, the boring head can be adapted to the finishing holes having different dimensions by exchanging the guide.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A boring head according to the present invention will be described based on an embodiment shown in the drawings. As shown in FIGS. 1 and 2, the main body 1 coaxially and integrally cooperates a small cylindrical portion 2 having an outer diameter smaller than the inner diameter of a prepared hole of a work and a large cylindrical portion 3 having an outer diameter larger than that. It is a connected shape. Large column 3
Is provided with a spanner hook 18 at the upper end.

[0008] Guide groove 1 provided on the upper peripheral surface of large cylindrical portion 3
6 is fitted with three synthetic resin guides 4 and fixed to the large cylindrical body 3 with set screws 23. A guide groove 17 is also provided on a peripheral surface of a portion where the small columnar portion 2 and the large columnar portion 3 are connected. The cemented carbide guide 5 is fitted therein and fixed to the large cylindrical portion 3 with set screws. A cutting blade fixing hole 6 and a chip discharge path 7 are united and opened at a portion where the small cylindrical portion 2 and the large cylindrical portion 3 are connected. The cutting blade 8 protrudes from the opening. The cutting blade 8 is fixed by a set screw 9 passing from the lower peripheral surface of the large cylindrical portion 3 to the cutting blade fixing hole 6.

A base 10 of a round bar-shaped cutting blade 8 is inserted into a cutting blade fixing hole 6 extending obliquely above a portion where the small cylindrical portion 2 and the large cylindrical portion 3 are connected, that is, in a direction away from the small cylindrical portion 2. . On the side surface of the base metal 10, a chordal contact 15 for receiving two setscrews screwed from the peripheral surface of the large cylindrical portion 3 is formed. An adjustment screw hole 11 is formed from the bottom of the cutting blade fixing hole 6 to the peripheral surface of the large cylindrical portion 3, and an adjustment screw 12 is screwed into the adjustment screw hole 11. The length of the cutting blade 8 protruding from the peripheral surface of the large cylindrical portion 3 is adjusted by the adjusting screw 12.

The small cylindrical portion 2 has a connection hole 14 provided with a connection screw 13 for screwing a shank (not shown), and the chip discharge path 7 extends and communicates with the connection hole 14.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Counter boring according to an embodiment will be described. In advance, as shown in FIG. 3, the length of the cutting blade 8 protruding from the peripheral surface of the main body 1 is adjusted to the inner diameter of the finishing hole of the work by an adjusting screw, and the cutting blade 8 is fixed to the main body 1 with a set screw. Further, the synthetic resin guide 4 and the cemented carbide guide 5 corresponding to the inner diameter of the finishing hole are fitted into the large cylindrical portion 3 and fixed with set screws.

A work having a prepared hole is fixed to a main shaft of a machine tool, and a shank fixed to a table is inserted through the prepared hole of the work. The small cylindrical portion of the main body 1 is screwed into the tip of the shank and integrally joined. Next, the main shaft is rotated to feed the shank in a pulling-out direction, and the inner diameter of the work is processed. As shown in FIG. 4, when the main body 1 is sent out relative to the work 20 in the direction of the arrow, the work 2
The small cylindrical portion 2 having a smaller inner diameter than the pilot hole 21
And then a large column 2 larger than the pilot hole of the work
The cutting blade 8 protruding from the lower end peripheral surface contacts the periphery of the prepared hole 21 of the rotating work 20 and cuts, and the prepared hole 21 is enlarged to a finishing hole 22 having a predetermined inner diameter. During this time, since the shank 19 is pulled in the axial direction, even if the shank is elongated,
There is no risk of bending. Therefore, there is no possibility that the bending accuracy of the finishing hole 22 is reduced due to the bending of the shank.
The elongated finishing hole 22 is also processed with high precision.

Further, as the processing proceeds, the large cylindrical portion 3
Enters the finishing hole 22, but the finishing hole 22
Since the guides 4 and 5 corresponding to the inner diameter of the hole are fitted, the finishing hole 22 is finished in a perfect circle. The chips cut by the cutting blade 8 enter the inside of the main body 1 through the chip discharge path 7 together with the cutting oil, and are then discharged to the outside together with the cutting oil from the cutting oil discharge port of the shank 19.

[0014]

As described above, the boring head according to the present invention is not a conventional system for counter boring by pressing the shank in the axial direction, but a system for counter boring by pulling the shank in the axial direction. Even if the hole to be finished is an elongated through hole using an elongated shank, there is no possibility that the shank is bent, so that there is an excellent effect that high-precision counterboring is performed and the tolerance of the hole to be finished can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view of a boring head according to an embodiment of the present invention;

FIG. 2 is a longitudinal sectional view of the boring head of FIG. 1,

FIG. 3 is a plan view of the boring head of FIG. 1;

FIG. 4 is a cross-sectional view showing a state of processing the work of the boring head of FIG. 1;

[Explanation of symbols]

 1: body 2: small column 3: large column 4: guide 5: guide 6: cutting blade fixing hole 7: chip discharge path 8: cutting blade 9: set screw 10: base metal 11: adjustment screw hole 12: adjustment Screw 13: Connecting screw 14: Connecting hole 15: Contact 16: Guide groove 17: Guide groove 18: Spanner hook 19: Shank 20: Workpiece 21: Preparatory hole 22: Finishing hole

Claims (4)

[Claims] 1. A small cylindrical portion (2) having a smaller diameter than a prepared hole (21) of a work (20), and a large cylindrical portion having a smaller diameter than the finishing hole (22) of the work and a larger diameter than the prepared hole. (3) a main body (1) integrally connected coaxially; a cutting blade fixing hole (6) provided at a connection portion between the small columnar portion and the large columnar portion of the main body; and a mounting in the fixing hole. From the cutting edge (8), the connection hole (14) for connecting to the shank (15) provided in the small column portion, and the chip discharge path (7) from the cutting blade fixing hole to the connection hole. A draw-out counter boring head, characterized in that: 2. The cutting blade fixing hole (6) has a cylindrical shape whose inside is inclined toward the large cylindrical portion in the axial direction and obliquely intersects with the axis, and the cutting blade (8) has the cutting blade fixing hole (6). And a base metal (10) inserted into the cutting blade fixing hole (6). The base metal (10) is fixed by a set screw (9) screwed from a peripheral surface of the large cylindrical part (3). An adjusting screw hole (11) is provided from the inner bottom to the peripheral surface of the large cylindrical portion, and the adjusting screw hole adjusts a protruding length of the cutting blade from the peripheral surface of the large cylindrical portion to the adjusting screw hole. 2. The screw is screwed in.
The drawn counter boring head described. 3. A work (20) on the peripheral surface of the large cylindrical portion (3).
The drawing counter boring head according to claim 1 or 2, wherein guides (4, 5) that fit in the finishing holes (22) are detachably fixed. 4. The shank (15) has a thread at a tip portion, and the connecting hole (14) has a female screw (13) inside which is fitted with the male screw.
A drawing counter boring head according to any one of the preceding claims.