JPH0818327B2 - Core drill - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core drill for drilling a work material such as concrete, and more specifically, it supplies a grinding material together with a cooling gas such as air to a cutting portion to improve cutting efficiency. The present invention relates to a core drill used in a dry drill device.

[0002]

2. Description of the Related Art A core drill of this type has a structure in which a plurality of block-shaped cutting tips are fixed to the tip of a cylindrical core at intervals in the circumferential direction, and a gap between the cutting tips in the circumferential direction. The portion mainly serves as a discharge promoting hole for cooling gas such as air and cutting chips.

Further, each cutting tip is formed by solidifying diamond grains as a cutting edge with a binder material, and in order to maintain a good cutting state, the diamond grain on the outermost surface finishes its role as a cutting edge. After the abrasion or loss, the binder material is appropriately abraded, so that a new diamond grain inwardly appears so that a sharpening action is required. The applicant of the present invention has found that it is very useful to send the abrasive together with compressed air as a cooling gas to the cutting site of the work material to simultaneously cool the cutting tip and perform the dressing action. Japanese Patent Laid-Open Nos. 3-86940 and 3-215201 provide a mixed fluid supply technology of an abrasive and compressed air.

[0004]

By the way, it has been proved that the above-mentioned technique of the present applicant improves the cutting efficiency by the positive sharpening action of the abrasive material. At the same time, the problem that the supply efficiency of the abrasive is hindered by the presence of the voids is present.

That is, it is necessary for the abrasive to be efficiently supplied to the tip surface of the cutting tip in order to achieve good sharpening. Since a carrier flow that doubles as discharge is generated,
As shown in FIG. 12, the abrasive material K is guided to the conveying flow and the tip surface 16a of the cutting tip 16 (the surface in contact with the work surface 36a).
It is discharged to the outside as shown by arrow E ₁ without reaching the area, that is, without contributing to the dressing. A part is guided to the outer periphery of the cutting tip 16 as shown by arrow E ₂ . The drawing shows a cutting portion in a so-called horizontal cut in which the drill is substantially horizontal, and reference numeral 14 indicates a tubular core, and reference numeral 1
Reference numerals 4c and 14d denote the tip end surface and the inner surface of the tubular core 14. Reference numeral 38 indicates a gap between the cutting tips 16, and reference numeral 36 indicates a work material such as concrete.

Incidentally, based on the consideration based on the experiment by the present inventors, when comprehensively judging the cutting situation at the cutting portion, the substantial cutting based on the sharpness is better than the cooling efficiency due to the existence of the void portion. It is presumed that the quality of the efficiency has a greater effect on the overall cutting efficiency.

Further, the cooling function by the cooling gas and the discharge of cutting debris etc. are achieved to some extent only by the minute gap between the cutting tip and the work material, which is secured by the diamond grains randomly protruding from the surface of the cutting tip. It is also confirmed that it will be done.

Therefore, in order to secure the cooling function of the cutting tip and the discharging function of the cutting waste by the cooling gas, the efficiency of supplying the abrasive to the tip surface of the cutting tip is given priority as much as possible, resulting in the cutting efficiency. Can be expected to be improved.

Therefore, the present invention provides a core drill capable of improving the efficiency of supplying the abrasive to the tip end surface of the cutting tip, thus improving the efficiency of cutting and the efficiency of use of the abrasive. To that end.

[0010]

SUMMARY OF THE INVENTION The present invention was devised to achieve the above object, and is characterized by a cylindrical core
A cutting chip with diamond grains held at the tip with a binder
In core drill flop is formed by fixed, cylindrical cutting site
The abrasive that is supplied together with the cooling gas from inside the core
The cutting tip to be sharpened is integrally formed in an annular shape, and the tip end surface of the cutting tip in contact with the surface to be cut is formed to be flat in series. The term “flat” here means an overall flat state in which microscopic undulations due to protrusions of diamond grains or the like are ignored. (same as below)

Further, according to the present invention, guide grooves for guiding the abrasive to the tip surface of the cutting tip may be formed on the inner peripheral surface of the cutting tip at intervals in the circumferential direction. .

According to the invention, the tip of the cylindrical core is
A cutting tip that holds diamond grains with a binder material
In a core drill that is fixedly attached, a cylindrical
A) The abrasive is supplied from the inside together with the cooling gas.
The cutting tip to be erected may be formed as an annular body in which a plurality of unit tips are continuously arranged in the circumferential direction, and the tip end surface of the cutting tip in contact with the work surface may be formed to be flat in series. it can.

Further, according to the present invention, at least a part of the abutting surfaces between the unit chips can be formed to be bent in the radial direction of the cutting chips.

[0014]

According to the present invention, the abrasive is supplied into the cylindrical core together with the cooling gas, and then supplied to the cutting site. The supplied abrasive is shaped like an annular cutting tip,
It prevents passage through to the outside in a state where it does not contribute to dressing, and is guided to the outside together with the cooling gas from the minute gap between the cutting tip and the work material due to the protrusion of diamond grains of the cutting tip. The abrasive is supplied to the tip surface area of the cutting tip in the circumferential direction by passing through a minute gap between the cutting tip and the work material.

Further, according to the present invention, the abrasive is supplied to the tip surface of the cutting tip in a state where the abrasive is evenly distributed in the circumferential direction of the cutting tip by the guide groove.

Further, according to the present invention, since the abutting surfaces between the unit tips are bent in the radial direction of the cutting tips, the abrasive material is prevented from flowing out from the abutting surfaces.

[0017]

1 to 3 show an embodiment of the present invention.
An example of transverse cutting in the air-cooled type is shown. The drill device 2 is supplied with a device body 6 having a core drill 4, a dust collecting means 8 for sucking cutting chips, an air supply pipe 10 connected to an air supply source such as a compressor (not shown), and an abrasive material K. The abrasive material supply means 12 is provided.

The core drill 4 comprises a tubular core 14 having a mounting portion 14a for attaching to the apparatus body 6 at the rear end, and an integrally formed annular cutting tip 16 fixed to the tip 14c of the tubular core 14. It is configured.

The cutting tip 16 is one in which diamond grains are held by a binder material such as a metal bond, and the cylindrical core 1
It is fixed to the tip 14c of No. 4 by means such as brazing, for example, through a relative concave-convex fitting structure. Since it is an annular unitary structure formed by integral molding, not only the fixing work is easy, but also the partial fixing accuracy in the circumferential direction does not vary. Since it is integrally molded, it is possible to avoid the separation of the fixing strength in the circumferential direction, and it is possible to completely eliminate the fear of a falling accident or the like. Further, the tip end surface 16a of the cutting tip 16 that is in contact with the surface to be cut is formed flat in series.

Further, in this example, the inner peripheral surface 1 of the cylindrical core 14 is
A supply groove 20 for forcibly guiding the abrasive material K to the cutting portion is formed in 4b in a spiral shape from the base portion to the tip of the cylindrical core 14. The supply groove 20 is formed in a reverse screw form with respect to the rotation direction of the core drill 4, and in this example, is formed in a left screw form with respect to the right rotation of the core drill 4. The applicant of the present invention has proposed in Japanese Patent Application No. 3-811309 a technique for forcibly guiding the abrasive K by a spiral feed groove that is particularly effective in the case of transverse cutting.

A drive shaft 22 connected to a drive source such as an electric motor is provided at the center of the apparatus main body 6, and a mounting portion 14a of the tubular core 14 is screwed to the tip thereof. Reference numeral 24 indicates a seal member.

The dust collecting means 8 is composed of a suction head 26 which is fitted to the core drill 4 and surrounds the cut portion, and a dust collecting hose 28 which connects the suction head 26 and a dust collector (not shown). The air supply pipe 10 is connected to a drive shaft 22 of the apparatus body 6 in a so-called swivel joint manner, and the drive shaft 22 has a radial horizontal supply passage 22a communicating with the air supply pipe 10 and a horizontal supply passage 22a. An axial vertical path 22b that communicates with and faces the inside of the tubular core 14 is formed.

The abrasive supply means 12 includes an abrasive tank 30 containing the abrasive K, an air supply pipe 10 and an abrasive tank 3.
0, and an opening / closing valve 34 provided in the grinding material supply path 32.

Next, the drilling process by the drill device 2 will be described. When the core drill 4 is moved while being rotationally driven, the cutting tip 16 bites against the work material 36 such as concrete and the drilling proceeds. Along with the perforation, the compressed air A supplied through the air supply pipe 10 is sent into the core drill 4 through the drive shaft 22, and the opening / closing valve 34 of the abrasive material supplying means 12 is opened. The material K is sent into the air supply pipe 10 from the abrasive supply path 32. The abrasive material K supplied into the air supply pipe 10 is conveyed by the flow of the compressed air A,
It is fed into the core drill 4.

The fed abrasive material K is collected in the supply groove 20, and is forcibly guided to the tip side by the spiral screw feeding action accompanying the rotation of the core drill 4, and is supplied to the cutting portion P.

At the cutting portion P, as shown in FIG. 3, a diamond grain 16b protruding from the tip surface 16a of the cutting tip 16 always forms a gap g between the cutting tip 16 and the surface 36a to be cut. Gap is compressed air A
It becomes a passage for the carrier flow.

The abrasive K is supplied into the gap g by the carrier flow and is discharged outward together with the cutting waste D. Since the gap g is an extremely narrow space, most of the supplied abrasive material K is in a state of contributing to the sharpening of the cutting tip 16, and this state is maintained over the entire circumference of the cutting tip 16.

As a result, the binder material 16c of the cutting tip 16 is worn by the contact with the abrasive material K and the dressing action is promoted, and the sharpness of the cutting tip 16 is maintained throughout the drilling operation without lowering. By improving the supply efficiency of the abrasive material K, not only the cutting efficiency can be improved, but also the use efficiency can be improved by the proper amount of the abrasive material K. In addition, the presence of the gap g causes the compressed air A
The cooling function is effectively maintained, and the cutting waste D is discharged.

Since the abrasive material K is forcibly guided by the supply groove 20, the abrasive material K is reliably supplied to the cutting site P even in transverse cutting under the influence of gravity, and most of the supplied material is for the intended purpose. It will contribute to the sharpening of a certain cutting tip 16.

Next, FIG. 4 and FIG. 5 show another embodiment. In the above-mentioned example, the abrasive material K is guided in the cutting tip portion in an unregulated state, but in the circumferential direction, it is dispersed. This is an example having a function.

On the inner peripheral surface of the integrally formed annular cutting tip 50, a plurality of guide grooves 52 for guiding the abrasive K to the tip end surface 50a are formed at intervals in the circumferential direction,
Each guide groove 52 is formed over the entire axial direction with a constant radial depth. Due to the formation of the guide groove 52, the cutting tip 50 has a structure in which a thick portion 50b having a thickness t _{1 in} the radial direction and a thin portion 50c having a thickness t ₂ are alternately present. The flattening of the tip surface 50a is the same as in the above example.

The abrasive K supplied into the cylindrical core 14 is
As shown in FIG. 5, it is directed by each guide groove 52, and is supplied to the tip surface 50a of the cutting tip 50 in a state of being evenly distributed in the whole circumferential direction. Since the flow of the abrasive material K is directed by the guide groove 52, the thick portion 50b is not eroded by the abrasive material K, and the life of the cutting tip 50 as a whole can be extended.

Next, FIGS. 6 and 7 show a modification of the above example. A plurality of guide grooves 54 are formed on the inner peripheral surface of the cutting tip 50 at intervals in the circumferential direction, and each guide groove 54 is
It is formed in a slanted surface shape in which the depth in the radial direction gradually increases toward the tip side, and a thick portion 50b having a thickness t ₁ and a thin portion 50d having a tip thickness t ₂ are alternately arranged. The guiding function of the abrasive K is almost the same as the above example.

Next, FIG. 8 and FIG. 9 show an example of forming a cutting tip into an annular body by continuously disposing a plurality of unit tips. The cutting tip 56 is composed of a plurality of unit tips 58 that are continuously arranged and fixed at the tip of the tubular core 14 without a gap in the circumferential direction, and are formed as one annular body by continuous arrangement.

Each unit tip 58 has an abutting surface 58a formed in a stepped shape having a substantially N-shaped planar shape, and the abutting surface 58a is formed in the radial direction of the cutting tip 56.
That is, an inner surface 58b, an outer surface 58c that are substantially parallel to the radiation line from the center, an outer surface 58c, and a central surface 58d that is bent at a substantially right angle are formed. In addition, a guide groove 60 having the same function as the above example is formed on the inner peripheral surface of each unit chip 58. Further, in the cutting tip 56, the tip surface 58e of each unit tip 58 constitutes a flat surface that is substantially flush.

According to the above construction, since the unit chips 58 are in contact with each other by the concave-convex fitting, the abrasive material K is prevented from flowing out in the radial direction, and the danger of leakage of the annular integrated abrasive material due to the divided construction is avoided. can do. In this example, even if the unit chips 58 are simply butted together, the outflow preventing function of the abrasive K and the structural connection strength can be secured, but the butted surfaces 58a can be joined together by brazing or the like. Of course, in this case, the integrated strength of the cutting tip 56 can be improved, and the fixing strength to the tubular core 14 can be increased to the same level as that of the integrally molded one in the above example.

Next, FIG. 10 and FIG. 11 show a modified example of annular integration by a divided structure. The cutting tip 62 includes a plurality of unit tips 64 that are continuously arranged and fixed in the circumferential direction without any gap.
And is formed as one annular body by continuous arrangement, as in the above example.

Each unit chip 62 has an abutting surface 62a inclined (bent) with respect to the radiation line, and
It has a guide groove 66. It is the same as in the above example that the tip surface 64b forms a flat surface that is substantially flush with the same, and the abutting surface 64a has the same function of preventing the abrasive material K from flowing out. The joining between the abutting surfaces 64a is also similar to the above example.

[0039]

According to the present invention, cutting is performed from inside the tubular core.
Almost all of the cutting material supplied to the part together with the cooling gas can be supplied in a state where the cutting tip can be dressed, so that the cutting efficiency can be improved and the usage efficiency of the abrasive can be improved. Can be planned. Well
In addition, as described in claim 2, the inner peripheral surface of the cutting tip is ground.
A guide groove that guides the cutting material to the tip surface of the cutting tip
By forming at intervals, the abrasive material
Provide the tip surface of the cutting tip in a state that it is evenly distributed in the circumferential direction.
Can be supplied to prevent partial erosion of the cutting tip.
It can be avoided and the life of the cutting tip as a whole is extended.
Can be. Further, as described in claim 4, a cutting tip
At least part of the butt surface between the unit chips of
Forming a shape that bends in the radial direction of the cutting tip
Prevents the abrasive from flowing out from the abutting surfaces.
Therefore, there is a danger of leakage of abrasive material with annular integration due to the divided configuration.
It can be avoided.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a core drill according to an embodiment of the present invention in a use state.

FIG. 2 is a perspective view of a main part.

FIG. 3 is an enlarged sectional view of an essential part showing a supply state of an abrasive material and a discharge state of cutting chips at a cutting portion.

FIG. 4 is a perspective view of a main part showing another example.

5 is a perspective view of a main part showing a supply state of an abrasive at a cutting portion in the example of FIG.

FIG. 6 is a main part perspective view showing another example.

FIG. 7 is a perspective view of a main part showing a supply state of an abrasive in a cutting portion in the example of FIG.

FIG. 8 is a plan view of a cutting tip showing an example of annular integration with unit tips.

9 is a perspective view of a main part in the example of FIG.

FIG. 10 is a plan view of a cutting tip showing a modified example of annular integration with unit tips.

11 is a perspective view of main parts in the example of FIG.

FIG. 12 is a perspective view of a main part of a cutting portion in a conventional product.

[Explanation of symbols]

 14 Cylindrical core 14a Cylindrical core tip 16,50,56,62 Cutting tip 16a, 50a Cutting tip tip surface 16b Diamond grain 16c Binder material 36a Work surface 52,54,60,66 Guide groove 58,64 Unit tip A Compressed air (cooling gas) K Abrasive P Cutting site

Claims (4)

[Claims] 1. A diamond grain is attached to the tip of a cylindrical core.
Core drill consisting of fixed cutting chips held by a binder
The cooling gas is supplied to the cutting site from inside the tubular core together with the cooling gas.
A core drill, characterized in that the cutting tip, which is sharpened by an abrasive material, is integrally molded in an annular shape, and the tip end surface of the cutting tip, which is in contact with the work surface, is formed to be flat in series. 2. The core drill according to claim 1, wherein guide grooves for guiding the abrasive to the tip surface of the cutting tip are formed on the inner peripheral surface of the cutting tip at intervals in the circumferential direction. 3. A diamond grain is attached to the tip of the cylindrical core.
Core drill consisting of fixed cutting chips held by a binder
The cooling gas is supplied to the cutting site from inside the tubular core together with the cooling gas.
The cutting tip that is sharpened by the abrasive is formed as an annular body in which a plurality of unit chips are continuously arranged in the circumferential direction, and the tip end surface of the cutting tip that is in contact with the work surface is formed flat in series. A core drill characterized by. 4. The core drill according to claim 3, wherein at least a part of the abutting surface between the unit tips is formed to be bent in the radial direction of the cutting tip.