JPH0469105A - Bevelling cutter - Google Patents

Abstract

PURPOSE:To prevent chips to intrude in and choke a bevelling cutter body for improving the performance of discharging the chips by providing a closing member for closing at least the front end of a gap produced between the inner peripheral surface of the bevelling cutter body and a drill groove. CONSTITUTION:While a drill 1 is rotated in the cutting rotational direction X the lower end of the drill is caused to abut against a workpiece W to drill a hole H with the drill 1. Chips are discharged out of a groove 5 of the drill 1 and a cutting edge 13 of each blade 11 of a bevelling cutter 2 forms an inverted truncated cone-like recess Ha on an opening edge of the hole H. The chips do not intrude between each blade 11 and a flank 6 of the drill since no gap is therebetween. Also, since a closing member 15 is mounted to a body part 8 and a bent piece closes the lower end of a cavity G, the chips are moved upward along the groove 5 of the drill 1 and blocked from intrusion into the body part 8. The chips collids with the bent piece of the closing member 15 without staying on the bevelling cutter 2 part to be discharged out of the drill 1 quickly.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a chamfer cutter used to form a recess having an inner diameter larger than the inner diameter of the opening edge of a hole formed by a drill. It is.

[Prior Art] Conventionally, this type of chamfering cutter includes a cylindrical main body that is fitted and fixed onto a drill, and a cylindrical main body that is formed at the front of the main body in the axial direction and that is attached to the opening edge of a hole drilled by the drill. Some are equipped with a cutting edge that forms a recess. According to this chamfering cutter, the chamfering work can be performed almost simultaneously with the drilling work using the trill.

[Problem to be Solved by the Invention] However, in the conventional chamfering cutter, a gap is created between the inner circumferential surface of the main body and the groove of the drill, so that the cut created during the drilling and chamfering operations with the drill is difficult. Powder can get into these gaps and clog them. Therefore, the newly generated chips become entangled with the chips stuck in the gap and cannot escape from the chamfering cutter. Then, there is a problem in that the chips, which have no place to escape as described above, get in the way of the drilling operation with the drill, and as a result, it becomes impossible to make new holes with the drill.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to prevent chips generated during work from entering the main body and clogging the main body, and to maintain good discharge performance of the chips. Our objective is to provide a chamfering cutter that can.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a cylindrical main body that is externally fitted and fixed to a drill, and a cylindrical main body that is formed at the front of the main body in the axial direction and that is drilled by the drill. In a chamfering cutter equipped with a cutting edge that forms a recess with an inner diameter larger than the inner diameter of the circumference at the opening edge of the hole, the gap between the inner peripheral surface of the main body and the groove of the drill is small (both Its gist is a chamfer cutter provided with a closing member that closes the front end.

[Operation] By employing the above configuration, when the chamfer cutter is attached to the drill, at least the front end of the gap created between the inner circumferential surface of the main body and the groove of the drill is closed by the closing member. This closing member prevents chips generated during drilling and chamfering operations from entering the main body.

[Example] An example embodying the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a partial front view of a drill l to which a chamfering cutter 2 of this embodiment is attached, and FIG. 4 is a bottom view of the drill 1. The drill l consists of a shank 3 and a shaft body 4, and the shaft body 4 is formed with two grooves 5 spiraling with respect to the axis. Two spiral flanks 6 are formed on the outer circumferential surface of the shaft body 4 by both grooves 5 . Here, assuming that the cutting rotation direction of the drill 1 is X, a land 7 having a radius of curvature B slightly larger than the radius of curvature A of the flank surface 6 is provided at the front edge of each flank 6 in the cutting rotation direction X. It is being

FIG. 2 is an exploded bottom view of the chamfering cutter 2, and FIG. 5 is a bottom view of the same chamfering cutter 2 attached to a drill l. The chamfering cutter 2 includes an annular body portion 8 that can be fitted onto the drill l, and the radius C of the inner peripheral surface 8a is set to be approximately the same as the radius of curvature B of the land 7. A pair of first screw holes 9 are provided at opposing positions of the main body portion 8, and a push screw 10 is screwed into each first screw hole 9. In this embodiment, the main body portion 8 is fastened to the drill l through these first screw holes 9 and push screws 10.

A pair of blade portions 11 spirally extend from a position below each first screw hole 9 in the main body portion 8 in correspondence with the flank surface 6 of the drill 1, and a conical oblique shape is provided at the lower end of the pair of blade portions 11. A curved surface 12 is formed. The front edge of the obliquely curved surface 12 with respect to the cutting rotation direction X of the drill l forms a cutting edge 13 .

The radius of curvature of the inner surface of each blade portion 11 is approximately the same as the radius of curvature A of the flank surface 6 at any location.

By the way, in the main body part 8, second screw holes 14 are formed at positions near the front side of each first screw hole 9 with respect to the cutting rotation direction X of the drill l, and a pair of closing members 15 made of a metal plate are formed. are attached to each second threaded hole 14. As shown in FIGS. 3 and 5, this closing member 15 is composed of a mounting piece 16 attached to the outer peripheral surface of the main body 8 and a bent piece 17 extending diagonally downward from the lower end of the mounting piece 16. ing. The lower end edge of the bent piece 17 is formed into an arc shape corresponding to the shape of the groove 5 of the drill l.

A screw insertion hole 18 is provided through the mounting piece 16 of the closing member 15, and the screw 19 inserted into the screw insertion hole 18 is screwed into the second screw hole 14 of the main body portion 8. A closing member 15 is fixed to the main body portion 8. In a state where the closing member 15 is fixed to the main body 8 in this way, the lower end of the bent piece 17 of the closing member 15 is inserted into the gap G formed between the groove 5 of the drill l and the inner circumferential surface 8a of the main body 8. It covers the lower end of.

When performing drilling and chamfering work using the drill 1 to which the chamfering cutter 2 configured as described above is attached, the drill 1 is attached to a chuck (not shown) of a drilling machine or the like, and the drill l is While rotating in the cutting rotation direction X, its lower end is brought into contact with a workpiece such as a workpiece.

Then, as shown in FIG. 1, a hole H is drilled in the work W by the drill L. At this time, cutting waste is discharged outward from the groove 5 of the drill 1. When the drill l is further advanced,
The cutting edge 13 of each blade part 11 of the chamfering cutter 2 comes into contact with the opening edge of the hole H drilled by the drill l. and,
This cutting edge 13 forms an inverted truncated conical recess Ha having an inner diameter larger than the inner diameter of the opening H at the opening edge of the hole H.

Since there is no gap between each blade part 11 and the flank surface 6 of the drill l, the chips generated due to the formation of the hole H and the recess Ha are removed.
No intrusion here. Further, in this embodiment, a closing member 15 is attached to the main body 8, and a bent piece 17 of the closing member 15 closes the lower end of the gap G in the main body 8.

Therefore, even if the chips move upward along the groove 5 of the drill 1 and try to enter the main body 8, the closing member 1
The bent pieces 17 of 5 prevent chips from entering into the main body 8. Therefore, the chips do not stay in the chamfer cutter 2 portion, but hit the bent piece 17 of the closing member 15 and are quickly discharged to the outside of the drill l.

As described above, according to the present embodiment, unlike the conventional technology which does not use the closing member 15, the gap G of the main body portion 8 is not clogged with chips, and the discharge performance of the chips can be maintained satisfactorily. Therefore, it is possible to prevent a decrease in the drilling ability of the drill l due to clogging with chips.

It should be noted that the present invention is not limited to the configuration of the embodiments described above, and may be modified as desired without departing from the spirit of the invention, for example, as described below.

(1) As shown in FIG. 6, the closing member 20 is constituted by an insertion portion 21 inserted into the gap G in the main body 8 and a locking portion 22 integrally formed at the lower end of the insertion portion 21. Good too. In this case, it is preferable that the inner surface of the closing member 20 is formed into a concave shape, and that the closing member 20 is pressed against the inner bottom surface of the groove 5 of the drill 24 while being slightly bent by the push screw 23 screwed into the main body part 8. .

(2) In addition to the above-mentioned closing members, a molten thermosetting resin is injected into the gap G in the chamfering cutter 2 attached to the drill l, 24, and the resin is heated and hardened to form the gap G. It may be something that blocks the area.

[Effects of the Invention] As detailed above, the chamfering cutter of the present invention prevents chips generated during hole-drilling and chamfering operations from entering the main body and clogging, and prevents the chips from being discharged. Good performance can be maintained, and a decrease in the drilling ability of the drill due to clogging of chips can be prevented.

[Brief explanation of the drawing]

1 to 5 show an embodiment embodying the present invention.
The figure is a partial front view of the chamfer cutter attached to the drill, Figure 2 is an exploded bottom view of the chamfer cutter, Figure 3 is a sectional view of the closing member, Figure 4 is a bottom view of the drill, and Figure 5 is the drill. It is a bottom view with a chamfer cutter attached to the
FIG. 6 is a partial front view showing a precedent for a closure member. 1, 24...Drill, 5...Groove, 8...Body part,
8a... Inner peripheral surface, 13... Cutting edge, 15.20...
Closing member, G: void, H: hole, Ha: recess, L: axis. Patent applicant: Omi Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A cylindrical main body (8) externally fitted and fixed to the drill (1, 24); , 24), the chamfering cutter is equipped with a cutting blade (13) that forms a recess (Ha) with an inner diameter larger than the inner diameter of the hole (H) at the opening edge of the hole (H) made by the hole (H). The inner peripheral surface (8a) of the main body (8) and the drill (1, 24)
) A chamfering cutter characterized in that it is provided with a closing member (15, 20) that closes at least the front end of the gap (G) formed between the groove (5) and the groove (5).