JPH09207014A - Center drill for drilling tool and drilling tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform easy removal of chips, with which a body is choked, through low-cost and simple structure. SOLUTION: A drilling tool and a center drill 14 are formed in such a manner that a center drill 14 and a body 16 are attached in a coaxial direction to a tool attaching part 10. A radial protrusion part consisting of a flange part 50 with diameter larger than the drilling diameter of a drill part 22 is formed on the center drill 14. The part on the tip side, closer to the flange part 50, of the interior of the body 16 is formed in such a manner to be choked with chips produced due to drilling. During pull-off of the center drill 14, the chips are pulled out together with the center drill 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center drill provided in a drilling tool for drilling a circular hole in a workpiece and a drilling tool equipped with the center drill.

[0002]

2. Description of the Related Art Conventionally, there has been known such a drilling tool as shown in FIG. This tool includes a tool mounting portion 90, a center drill 92 is removably mounted on the center portion of the tool mounting portion 90, and a cylindrical body 9 is provided at a position coaxial with the center drill 92.
4 is fixed. A drill portion is formed at the tip of the center drill 92, and a blade 93 is also formed at the tip of the body 94, so that the drill portion projects further toward the tip side than the blade 93.

When the entire drilling tool is pressed against a workpiece (for example, a wall 96) while rotating at a high speed, first, a center drill 92 first drills and positions the drill.
Further, the blade 93 of the body 94 is cut around the periphery thereof, so that a hole having substantially the same diameter as the body 94 is finally formed in the wall 96.

Immediately after the above-mentioned drilling with such a drilling tool, as shown in FIG. 7B, the chips of the wall 96 are placed in the space between the center drill 92 and the body 94. 95 is in a clogged state. Since the next perforation cannot be performed in this state, it is necessary to remove the chips 95 before the perforation.

Conventionally, the following means have been known as means for removing the chips 95.

A) As shown in FIG. 8, a small-diameter through hole 97 is provided in the base end wall of the body 94 so that the scrap removing rod 98 can be inserted into the body 94 through the through hole 97.
The scrap 95 sticks out the chips 95 toward the tip side.

B) Not only the center drill 92 but also the body 94 is configured to be attachable / detachable to / from the tool mounting portion 90, and the chips 95 can be taken out by removing the body 94 from the tool mounting portion 90.

[0008]

In the means a), a dedicated dust removing rod 98 must be provided in addition to the drilling tool body, and the number of parts increases. Further, since the through hole 97 is provided in the base end wall of the body 94, the body 94 is disadvantageous in strength.

On the other hand, in the means of b), the center drill 9
A body 94 having a diameter several steps larger than 2 must be attached to and detached from the tool mounting portion 90. This attaching / detaching work is larger than the attaching / detaching work of the center drill 92, and the work efficiency is poor. In recent years, various structures have been developed in which the body 94 can be relatively easily attached to and detached from the tool mounting portion 90. In any structure, the tool mounting portion 90 and the body 94 are machined to have a complicated mounting portion. Therefore, there is a disadvantage that the initial cost of the tool is increased accordingly.

In view of the above circumstances, it is an object of the present invention to provide a center drill and a drilling tool for a drilling tool which have a simple and inexpensive structure and which can easily remove chips in the body. .

[0011]

As a means for solving the above problems, the present invention provides a tool mounting portion of a drilling tool in which a cylindrical body having a blade at its tip is mounted on the center axis of the body. In the center drill of the drilling tool, which is detachably mounted at the position, has a drill portion at least at the tip portion, and the drill portion projects toward the tip side from the tip blade of the body, the drill portion and the tool mounting The center drill is provided with a radial protruding portion that protrudes outward in the radial direction from the drilling diameter of the drill portion at a position between the mounting portion and the mounting portion to be mounted on the drilling portion. It is a tool.

According to the hole drilling tool and the center drill, since the chips produced by the drilling are clogged in the body at a position closer to the tip than the radial projection of the center drill, the center drill is used in this state. When the tip is pulled out from the mounting portion, the chips are caught by the radial protrusions and taken out of the body together with the center drill.

As the radial projecting portion, a collar portion having a diameter larger than the drilling diameter of the drill portion and smaller than the inner diameter of the body is preferable over the entire circumference.

If the diameter of the collar portion is smaller than the inner diameter of the body, it can be inserted into the body without any inconvenience. However, if the diameter of the collar portion is set to be substantially the same as the inner diameter of the body. Even the fine chips generated during drilling can be captured by the flange portion, and the chips can be recovered from the body by the subsequent withdrawal of the center drill.

Further, if the collar portion is formed such that the center portion thereof is recessed toward the tool mounting portion side rather than the peripheral portion, the chips can be reliably captured in the recessed portion.

The radial projection may project outward in the radial direction from the drilled diameter of the drill only in a part of the circumferential direction. For example, the center drill may be provided so as to penetrate the center drill in the diametrical direction,
It may be a retaining ring or the like that is partially notched in the circumferential direction. With regard to the former, by making this into a ring shape, even if this radial protrusion moves in the ring longitudinal direction with respect to the center drill body, there is no concern that the radial protrusion will fall out.

The radial projection may be integrally fixed to the center drill by welding or the like. However, if the radial projection is detachably attached to the center drill body, the diameter of the body is changed. However, by exchanging the radial protrusion having a shape corresponding to this and mounting it on the center drill, the center drill can be commonly used regardless of the diameter of the body.

[0018]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG.

The drilling tool shown here is a tool mounting portion 10.
It has. The drive connecting portion 12 is fixed to the base end (left end in FIG. 1) of the tool mounting portion 10, and the tip (right end in the same figure).
A center drill 14 and a body 16 are coaxially attached to the. By connecting the drive connecting portion 12 to a drive source (not shown), the tool mounting portion 10, the center drill 14, and the body 16 are integrally driven to rotate.

As a mounting portion of the center drill 14,
A circular mounting hole 18 is provided at the tip of the tool mounting portion 10 along the central axis thereof, and an insertion hole 20 having a modified cross section (rectangular shape in the example) is formed in the back of the mounting hole 18. Has been done. On the other hand, the center drill 14 has a drill portion 22 at its tip and a round shaft-shaped mounting portion 24 inserted into the mounting hole 18 at its base end. At the end of 24, an insertion portion 26 having a rectangular cross section that is fitted into the insertion hole 20 is formed. The center drill 14 is prevented from rotating by fitting the insertion portion 26 having the modified cross-section and the insertion hole 20.

A peripheral groove 28 is formed in the middle of the mounting portion 24 over the entire circumference thereof, and a locking portion for locking the peripheral groove 28 around the mounting hole 18 in the tool mounting portion 10. 30 are provided. Specifically, the tool mounting portion 10 is provided at two locations in the circumferential direction from the outer peripheral surface thereof to the mounting holes 1
8 through holes 32 are provided, and balls 34 having a diameter that fits into the circumferential groove 28 are inserted into the through holes 32. Further, a circumferential groove 36 is formed over the entire circumference at the outer peripheral portion of the portion where the through hole 32 is formed, and a C-shaped expanding / reducing member 38 made of an elastic material and having a C-shape in front view is formed in the circumferential groove 36. It is fitted in the diameter state. The balls 34 are urged radially inward by the elastic restoring force of the diameter-reducing member 38 in the diameter-reducing direction, and the engagement state between the balls 34 and the peripheral groove 28, that is, the locked state of the center drill 14, is maintained. It is supposed to be.

In the present invention, regardless of the attachment / detachment structure of the center drill 14, for example, a bolt is screwed into the tool mounting portion 10 from the side, and the center drill 14 is locked at its tip. Good.

The body 18 is a donut plate-shaped base end wall 40.
And a body main body 42 that extends in the axial direction from the outer peripheral portion of the base end wall 40. A notch 44 is formed at the tip of the body main body 42.
Is formed, and an unillustrated blade is formed around the notch 44. A female screw 46 is formed on the inner peripheral surface of the base end wall 40, while a male screw 48 is formed on the tip end of the tool mounting portion 10. By screwing the female screw 46 into the male screw 48, The body 16 is fixed to the tool mounting portion 10. In this state, the center drill 14 is located on the central axis of the body 16, and the drill portion 22 is
It is in a state of protruding toward the tip side (right side in FIG. 1) from the tip blade of No. 6.

Further, as a feature of this drilling tool, the center drill 14 is provided with a collar portion 50. The collar portion 50 is formed in a donut plate shape having an inner diameter to be fitted onto the center drill 14, and the outer diameter thereof is the body body 4
Slightly smaller than the inner diameter of 2 (ie almost equal)
It is set to the diameter.

As the fixing structure, the center drill 1
4, in the vicinity of the mounting portion 18, a step portion 52 is formed in which the outer diameter on the base end side becomes sharply smaller than the outer diameter on the tip end side, and the thickness of the collar portion 50 is thicker than the step portion 52. A peripheral groove 54 is formed at a position displaced by the amount toward the base end portion side. Then, in the state where the collar portion 50 is externally fitted from the side of the base end portion and the inner edge portion thereof is abutted against the step portion 52, the retaining ring 56 in which the circumferential groove 54 is partially cut out in the circumferential direction is formed. By being fitted, the collar portion 50 is fixed to the root portion of the center drill 14.

Next, the operation of this drilling tool will be described.

When the drive connecting portion 12 is connected to a drive source (not shown) and is pressed against a workpiece such as a wall while the entire tool is driven to rotate at high speed, first, the drill portion 22 of the center drill 14 makes a hole. The body 1 is finally positioned by performing positioning, and then cutting the tip edge of the body 16 around it.
Holes of approximately the same diameter as 6 are drilled in the workpiece.

After completion of such drilling, when the tool is removed from the work piece, as shown in FIG. 4A, the chips 60 are placed in the space between the center drill 14 and the body 16.
Is clogged. Here, in the conventional drilling tool shown in FIG. 7 and the like, the center drill has a straight shape and has no portion for catching with the chips. Therefore, even if the center drill is pulled out from the tool mounting portion, It is difficult to remove 60, but with the drilling tool shown in FIGS.
The center drill 14 is provided with a collar portion 50.
Since the chips 60 are clogged on the tip side from 0, the center drill 14 is pulled out from this state against the locking force of the ball 34 to the tip side.
4, the chips 60 can be reliably taken out from the body 16 (FIG. 4 (b)), and the next drilling operation can be smoothly performed.

The chips 60 can be taken out by removing the body 18 from the tool mounting portion 10, but the body 18 can be removed from the center drill 14.
The diameter is several steps larger than that, and a large amount of work is required to attach and detach it. On the other hand, if the chips 60 are taken out by pulling out the center drill 14 as described above, the work is simple and the efficiency is dramatically improved.

The diameter of the collar portion 50 may be smaller than the inner diameter of the body 16 and larger than the hole diameter of the drill portion 22 of the center drill 14, and for example, the collar portion slightly larger than the hole diameter. Even if 50 is provided, the block-shaped chips 60 can be taken out. However, the outer diameter of the collar portion 50 is set to be substantially equal to the inner diameter of the body 16 (that is, the collar portion 5 is set inside the body 16 with a slight gap).
By setting 0 as a size that can be fitted without difficulty), fine chips generated in the body 16 at the time of punching work can be captured by the collar portion 50, and the chips are also extracted when the center drill 14 is subsequently withdrawn. There is an advantage that it can be collected.

In particular, the cross-sectional shape of the collar portion 50 is such that the central portion is recessed toward the base end side rather than the outer peripheral portion, for example, as shown in FIG.
If the curved shape as shown in FIG. 9A or the shape having a side wall 58 on the outer peripheral portion of the collar portion 50 as shown in FIG. There is an advantage that the chips can be more reliably collected in the recessed portion. Collar part 50
The front shape of is not limited to a circle, and may be set to various shapes such as a polygon such as a rectangle, an ellipse, and a horseshoe.

Further, based on the same principle of solving the problem, the center drill 14 is provided with a radial protruding portion in which only a part in the circumferential direction protrudes outward in the radial direction from the hole diameter, instead of the flange portion 50.
Even if it is provided in the above, the chips 60 can be taken out well. For example, in the structure shown in FIG. 2, it is possible to omit the collar portion 50, mount only the retaining ring 56 on the center drill 14, and use this retaining ring 56 as the radial protrusion.

Further, the center drill 14 is provided with a through hole penetrating the center drill 14 in the diameter direction, and a shaft 62 as shown in FIG. 6A or a plate 64 as shown in FIG. 6B is inserted into the through hole. Even if you fix it by fixing it with a simple structure,
The chips 60 can be taken out by utilizing both ends of the shaft 62 and the plate 64. In this case, the plate 64 is not limited to a specific shape, and other polygonal shapes other than the illustrated rectangular shape can be freely set. Further, instead of fixing it to the center drill 14 in the penetrating state as described above, for example, a structure in which a screw hole is provided on the side surface of the center drill 14 and a bolt is screwed into this to project the bolt in the radial direction, The chips 60 can be taken out.

When the through hole is provided in the center drill 14, it is used as a radial protruding portion to be inserted into the through hole as shown in FIG.
(C) Rings 66, 6 of various shapes as shown in (d)
8 may be introduced. These rings 66,
For example, 68 is configured to be separable at an appropriate position, and is inserted into the through hole penetrating in the diametrical direction of the center drill 14 in a separated state, and then connected to the center drill 14 by being connected at the aforementioned separating point. It is possible. When these rings 66, 68 are used, there is an advantage that even if the rings 66, 68 move in the ring longitudinal direction with respect to the center drill 14, the rings 66, 68 do not have to fall out of the center drill 14.

In the present invention, the position in which the radial projections such as the collar 50 are provided in the center drill 14 is not particularly limited, and may be appropriately set within a range where a sufficient drilling stroke can be secured. Further, the means for fixing the radial projection to the center drill 14 is not particularly limited, and the radial projection may be directly fixed to the center drill 14 by welding, for example. However, as illustrated in FIG. 2, if the radial protrusions such as the collar 50 are configured to be attachable to and detachable from the center drill 14, even if the diameter of the body 18 is changed, the diameter can be adapted accordingly. By exchanging the directional protrusion with a different shape (for example, a collar 50 having a different diameter), the center drill 1 can be used regardless of the diameter of the body 18.
4 can be commonly used, and there is an advantage that versatility can be improved.

[0036]

As described above, according to the present invention, the center drill is provided with the projecting portion in the radial direction, and the center drill is pulled out from the tool mounting portion so that the chips clogged in the body can be taken out together. Therefore, there is an effect that the chip removing operation can be facilitated with a simple and inexpensive structure.

In particular, when the radial protruding portion is a collar portion having a diameter substantially equal to the inner diameter of the body, fine chips generated during perforation can also be caught by the collar portion, and The effect of being able to collect the above chips from the inside of the body is also obtained by pulling out the center drill.

Furthermore, if the central portion of the collar portion is recessed toward the tool mounting portion side rather than the peripheral portion, the chip can be reliably captured by utilizing this recessed portion.

The radial projection may be provided in the center drill in a state of penetrating the center drill in the radial direction, whereby the chips can be taken out with a simple structure. Further, by making it ring-shaped, it is possible to reliably prevent the radial protrusions from falling off the center drill.

Further, if the radial protrusion is detachably attached to the center drill main body, even if the diameter of the body is changed, the radial protrusion having a diameter corresponding to this can be replaced to form a center drill. By mounting the center drill, the center drill can be used in common regardless of the diameter of the body, and the versatility of the center drill can be secured.

[Brief description of drawings]

FIG. 1 is a sectional front view of a punching tool according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a mounting structure of a center drill in the hole making tool.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4A is a sectional front view showing a state in which chips are clogged in the body immediately after drilling, and FIG. 4B is a sectional front view showing a state in which the chips are taken out together with the center drill from the same state. is there.

5 (a) and 5 (b) are cross-sectional front views showing a modified example of a collar portion provided in the center drill.

6 (a), (b), (c), and (d) are front views showing a modified example of a radial projection portion other than the flange portion.

FIG. 7 (a) is a sectional front view showing a state before drilling with a conventional drilling tool, and FIG. 7 (b) is a sectional front view showing a state in which chips are clogged in the drilling tool. It is a figure.

FIG. 8 is a sectional front view showing how chips are removed by inserting a chip removing rod into the hole making tool.

[Explanation of symbols]

 10 Tool Mounting Part 12 Drive Connection Part 14 Center Drill 16 Body 22 Drill Part 24 Mounting Part (Mounting Part) 30 Locking Part 50 Radial Protrusion 60 Chips 62 Shaft (Radial Protrusion Part Penetrating the Center Drill) 64 Plate (Radial projection that penetrates the center drill) 66, 68 Ring

Claims (10)

[Claims] 1. A tool mounting portion of a drilling tool to which a cylindrical body having a blade at its tip is mounted, is detachably mounted at a position on the central axis of the body, and has a drill portion at least at the tip. In a center drill of a drilling tool in which a lever drill portion projects toward the tip side from the tip blade of the body, at a position between the drill portion and a mounting portion mounted on the tool mounting portion, A center drill characterized by having a radial protrusion that protrudes outward in the radial direction from the diameter of the drilled hole. 2. The center drill according to claim 1, wherein the radial projecting portion is a collar portion having a diameter larger than a drilling diameter of the drill portion and smaller than an inner diameter of the body over the entire circumference. A center drill featuring. 3. The center drill according to claim 2, wherein the diameter of the collar portion is set to be substantially equal to the inner diameter of the body. 4. The center drill according to claim 2, wherein the collar portion has a shape in which the central portion is recessed toward the tool mounting portion side rather than the peripheral portion. 5. The center drill according to claim 1, wherein the radial projecting portion projects outward in the radial direction from the drilling diameter of the drill only in a part in the circumferential direction. . 6. The center drill according to claim 5, wherein the radial projection is provided on the center drill in a state of penetrating the center drill in the radial direction. 7. The center drill according to claim 6, wherein the radial protrusion has a ring shape. 8. The center drill according to claim 5, wherein the radial protrusion is a retaining ring partially cut out in the circumferential direction. 9. The center drill according to claim 1, wherein the radial protrusion is configured to be attachable to and detachable from the center drill body. 10. A tool mounting part, a cylindrical body mounted on the tool mounting part and having a blade at a tip, and removably mounted at a position on the central axis of the body in the tool mounting part. A drilling tool, comprising the center drill according to any one of Items 1 to 9.