JPH09272007A - Cutter for drilling and drilling tool with cutter for drilling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily remove chips packed within a body, using an unexpensive and simple structure. SOLUTION: This invention concerns with a cutting tool for drilling, which has a cylindrical body, and a drilling tool, in which the cutting tool for drilling is installed. A plurality of cutting edge parts are arranged side by side in the circumferential direction at the tip end of a main body 42 of the body in such a manner that the cutting edge parts are more projected than the body in both tip end and radial directions. In addition, one part of cutting edge part 45B is formed as an inner cutting edge part, whose inward projection in the diametral direction is greater than that of the other cutting edge part 45A. The inner cutting edge parts 45B are arranged in a concentrated manner in a domain whose central angle is less than 180 deg..

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a hole forming tool as described above, one shown in FIG. 8 (a) is known. 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. A blade 93 is also formed at the tip of the body 94 to form a drilling blade, and the drill portion protrudes toward the tip from 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 periphery thereof is cut by the blade 93 at the tip of the body 94, so that a hole having substantially the same diameter as the body 94 is finally formed in the wall 96.
Will be drilled.

Immediately after the above-mentioned drilling with such a drilling tool, as shown in FIG. 8B, 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. 9, a through hole 97 having a small diameter 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 such circumstances, it is an object of the present invention to provide a punching tool having a simple and inexpensive structure and capable of easily removing chips in the body, and a punching device including the same. And

[0011]

[Means for Solving the Problems] As a means for solving the above problems, the present invention has a cylindrical body, and perforates a workpiece by being pressed against the workpiece while being rotationally driven. In the punching tool configured as described above, a plurality of blade portions are arranged side by side in the circumferential direction in a state of protruding in the tip direction and the radial direction from the body at the tip of the body, and one of these blade portions is arranged. The parts are concentratedly arranged in a region having a central angle of less than 180 ° as an inner cutting blade part having a larger amount of protrusion inward in the radial direction than the other blade parts.

When a hole is punched using this punching tool,
Chips remain inside the body of the punching tool, but the radius of this chip is almost equal to the radius of the inscribed circle of the inner cutting blade, and the radius of the inscribed circle of blades other than the inner cutting blade. Smaller than. Therefore, by displacing the chips by a small amount in the direction away from the inner cutting blade, the chips can be easily extracted from the body through the inner space of each blade.

The number of the inner cutting blades may be one or plural, and may be appropriately set according to the load. Even when a plurality of blades are provided, the inner cutting blade portions may be provided intermittently or continuously. However, in the latter case, the area where the inner cutting blade portion is disposed can be minimized, and the chips can be more easily extracted by that amount.

If the tip of the inner cutting blade portion is located rearward of the other blade portions, the blade portions other than the inner cutting blade portion first excavate, and then the inner cutting blade portion Since the excavation will be carried out supplementarily, the excavation resistance received by the inner cutting edge part will be low, the burden will be lightened, and the amount of chips discharged due to the increase in the protrusion amount of the inner cutting edge part will increase. At the same time, it becomes possible to greatly increase the excavation speed.

The present invention also provides the above-described hole-drilling tool, a center drill arranged on the central axis of the hole-drilling tool so as to project further than the tip of the tool, and the hole-drilling tool and A tool mounting part to which a center drill is mounted is provided, and the tool mounting part, the drilling tool, and the center drill are configured to perform punching on the workpiece by being pressed against the workpiece while being rotationally driven. It is a thing.

In order to eccentrically dispose of the chips inside after using this drilling tool, the center drill is configured to be attachable to and detachable from the tool mounting portion, and the tool is mounted during or after the drilling work. You may remove the center drill from the part, or make the diameter of the tip part of the center drill larger than the diameter of the rear part than this to secure a gap between this center drill and chips, The chips may be eccentric by this gap.

[0017]

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 for 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 on the tip side, and the tip portion 22 of the drill portion 22.
a has a larger diameter d than its rearward portion. The mounting hole 18 is provided at the base end of the center drill 14.
A mounting portion 24 having a round shaft shape to be inserted therein is formed, and an insertion portion 26 having a rectangular cross section that is fitted into the insertion hole 20 is formed at an end portion of the mounting portion 24. 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.

The body 18 is a donut plate-shaped base end wall 40.
And a cylindrical body main body 42 that extends in the axial direction from the outer peripheral portion of the base end wall 40. 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.
The body 16 is fixed to the tool mounting portion 10 by screwing the female screw 46 into the body 8.

A plurality of notches 44 that are evenly arranged in the circumferential direction are formed at the tip of the body body 42, and the edges of each notch 44 are
Blade portions 45A and 45B made of a sintered alloy or the like are provided. These blade portions 45A and 45B are the body body 4 described above.
It is in a state of projecting to the tip side and both sides in the radial direction from 2,
In the illustrated example, the three blade portions 45B are provided in a concentrated manner in a region having a central angle of less than 180 ° (region in which the central angle is approximately 90 ° in FIG. 4), and there are more blade portions 45A than these blade portions 45B. Are arranged in a region other than the above region.

Here, the blade portion 45B is the blade portion 45.
It is an inner cutting blade portion that has a larger amount of protrusion inward in the radial direction than A. That is, these inner cutting blades 4
The radius Rb of the inscribed circle of 5B is smaller than the radius Ra of the inscribed circle of the other blade portions 45A.

Further, as shown in FIG. 5, the tip of the blade portion 45A is in a state of projecting forward (leftward in the figure) by a dimension t from the tip of the inner cutting blade portion 45B. In other words, the inner cutting blade portion 45B is arranged at a position behind the other blade portions 45A by the dimension t.

The blades 45A and 45B and the body form a hole-making tool according to the present invention. In a state where the hole-cutting tool and the center drill 14 are mounted on the tool mounting portion 10. , Center drill 14
Is located on the central axis of the body 16, and the axial length of the center drill 14 is set so that the drill portion 22 projects toward the tip side (right side in FIG. 1) with respect to the tip of the body 16.

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.

More specifically, of the blade portions 45A and 45B, first, the blade portion 45A comes into contact with the workpiece for excavation, and the inner cutting blade portion 45B comes into contact with the workpiece at a later stage, whereby the blade portion 45A is The area radially inward of the excavation area by is additionally excavated. As a result, as shown in FIG. 6, a gap 52 having a dimension substantially equal to the protruding dimension of the inner cutting blade portion 45B from the body 42 is secured on the radially inner side of the body main body 42, and the gap 52 is cut through the gap 52. The powder will be actively discharged into the body 16.
Further, since the diameter of the drill tip portion 22a of the center drill 14 is larger than that of the rear portion thereof, a gap 54 is formed around the center drill 14 by the difference in diameter.

In this way, when the entire tool advances and the body 42 penetrates the workpiece, the drilling is completed.
When the tool is removed from the work piece after completion of this drilling, the cylindrical chips 60 are clogged in the space between the center drill 14 and the body 16 as shown by the solid line in FIG. Immediately after the perforation, the outer peripheral surface of the chip 60 is in pressure contact with the inner cutting blade portion 45B, but in this state, the tool is extracted from the workpiece and the whole is directed downward and shaken in the radial direction. If the chip 60 is displaced in the same direction by the above-mentioned gap 54 minutes (that is, the chip 60 is moved to the center drill 1).
4 is made eccentric in the direction away from the inner cutting blade portion 45B), the radius Rb of the chips 60 is the blade portion 45A.
Since it is smaller than the radius Ra of the inscribed circle, the chips 60 can be easily removed from the inside of the body 16 through the inner space of the blade portions 45A and 45B as shown in FIG.

Further, in this embodiment, the tip of the inner cutting blade portion 45B is located rearward of the tip of the other blade portion 45A, and first the blade portion 45A is first excavated and then the inner cutting portion is cut inside. Since the blade portion 45B is used for auxiliary excavation, excavation resistance is low. Moreover, the gap 5 is increased by the amount of increase in the inner protrusion amount of the inner cutting blade portion 45B.
2 can be increased, so that the discharge of chips through the gap 52 can be promoted, and the advantage that the excavation speed can be increased in general can be obtained.

In the present invention, the inner cutting edge portion 45
It suffices that the number of Bs is less than half of the total number of blades, and it may be singular, or even if there are a plurality of Bs, the inner cutting blades 45B are intermittently arranged in the region where the central angle is less than 180 °. It may be arranged. However, if all the inner cutting blades 45B are continuously arranged as in the above-described embodiment,
The area in which the inner cutting blade portion 45B is disposed can be minimized, and there is an advantage that the chips 60 can be easily extracted by that amount.

Further, in the above embodiment, the tip portion 22a of the center drill 14 has a large diameter, and the center drill 14 has the same diameter.
By using the gap 54 formed in the periphery of the center drill 14, it is shown that the chips 60 are eccentrically removed with the center drill 14 still attached.
When the diameter of 4 is uniform and the gap 54 is hardly formed in the periphery thereof, the center drill 14 is extracted from the tool mounting portion 10 during the drilling work or after the drilling work is completed, so that the chips 60 can be removed after the drilling. It is possible to make it eccentric, and the chips 60 can be easily extracted similarly to the above.

[0034]

As described above, according to the present invention, a plurality of blade portions are provided at the tip of a cylindrical body in the circumferential direction so as to project in the tip direction and the radial direction from the body, and these blades are also provided. The center angle is 180 degrees as a part of the inner cutting blade that has a larger amount of protrusion inward in the radial direction than the other blades.
Since they are concentrated in the area of less than °, there is an effect that the chips left in the body can be easily removed without using a special tool or removing the body from the tool mounting portion.

When a plurality of inner cutting edge portions are provided,
If all the inner cutting blades are continuously arranged, the area where these inner cutting blades are disposed can be minimized, and the effect of further facilitating the chip removal operation can be obtained.

Further, if the tip of the inner cutting blade portion is located rearward of the other blade portions, the amount of inward projection of the inner cutting blade portion is increased to increase the gap formed during excavation, thereby cutting chips. It is possible to reduce the excavation resistance received by the inner cutting blade portion while promoting the discharge of the excavated water, and it is possible to obtain the effect of significantly increasing the excavation speed as a whole.

[0038] Further, the hole-drilling tool, a center drill arranged on the central axis of the hole-drilling tool so as to project further than the tip of the tool, and the hole-drilling tool and the center drill. In a drilling tool having a tool mounting part to be mounted, the center drill is configured to be attachable / detachable to / from the tool mounting part, or the diameter of the tip part of the center drill is set to the diameter of a part behind the center drill. If it is made larger, the chips can be eccentric in the body despite the presence of the center drill, and this eccentricity can easily remove the chips.

[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. 4 is a front view of the punching tool immediately after punching.

FIG. 5 is a view taken in the direction of arrow B in FIG. 4;

FIG. 6 is a cross-sectional side view showing a state where a boring operation is performed by the boring tool.

FIG. 7 is a cross-sectional side view showing how chips are extracted from the punching tool.

FIG. 8 (a) is a sectional front view showing a state before drilling with a conventional drilling tool, and FIG. 8 (b) is a sectional front view showing a state in which the drilling is performed and chips are clogged in the drilling tool. It is a figure.

FIG. 9 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 22a Drill Tip Part 24 Mounting Part (Mounting Part) 42 Body Main Body 45A Blade Part Other Than Inner Cutting Blade Part 45B Inner Cutting Blade Part

Claims (6)

[Claims] 1. A punching tool having a cylindrical body and configured to punch a workpiece by being pressed against the workpiece while being rotationally driven, wherein a plurality of blades are provided at a tip of the body. The parts are arranged side by side in the circumferential direction in a state of protruding in the tip direction and the radial direction from the body,
A part of these blades has a central angle of 1 as an inner cutting blade that has a larger radial inward projection than the other blades.
A drilling tool characterized by being arranged in a region less than 80 °. 2. The drilling tool according to claim 1, wherein
A punching tool comprising a plurality of the inner cutting blades and continuously disposing all the inner cutting blades. 3. The punching tool according to claim 1, wherein the tip of the inner cutting blade portion is located rearward of the other blade portions. 4. A hole-drilling tool according to claim 1, and a center drill arranged on the central axis of the hole-drilling tool so as to project further than the tip of the tool. , A tool mounting portion to which the hole-drilling blade and the center drill are mounted, and the tool-mounting portion, the hole-drilling blade, and the center drill are pressed against the workpiece while being rotationally driven to punch the workpiece. A punching tool having a punching tool, which is configured to perform. 5. The drilling tool according to claim 4, wherein the center drill is configured to be attachable to and detachable from the tool mounting portion. 6. The drilling tool according to claim 4, wherein a diameter of a tip portion of the center drill is larger than a diameter of a portion behind the center drill.