JP3854587B2 - Drilling tool for grinding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grinding and drilling tool used when a small-diameter grinding hole is drilled in a member to be ground such as concrete, stone, building material, and glass.
[0002]
[Prior art]
Conventionally, when attaching a decorative plate to a concrete wall of a building, it is necessary to grind and drill many small-diameter holes for anchor bolts in the concrete wall. For such small-diameter grinding drilling, a drilling machine with a grinding drilling tool attached to the tip is used.
[0003]
Moreover, the grinding drilling work of the grinding drilling is performed as follows, for example. First, as shown in FIG. 5, the grinding drilling tool 21 is attached to the motor shaft 43 provided inside the casing 42 of the drilling machine 41 via the fastening portion 44. Next, the collection chamber 45 provided at the tip of the casing 42 is brought into contact with the concrete wall K, and the tip of the grinding drilling tool 21 is aligned with the drilling position. Next, a cooling fluid such as air or water is supplied to the inside of the grinding drilling tool 21, and the grinding drilling tool 21 is rotated at a high speed of, for example, about 2000 rpm while jetting the cooling fluid from the tip of the grinding drilling tool 21. Next, a small hole H is drilled in the concrete wall K by pressing the grinding drilling tool 21 against the concrete wall K at a feed rate of, for example, about 7 mm / min. At this time, the concrete core waste flowing into the recovery chamber 45 is discharged while being sucked by the suction pipe 46 together with the cooling fluid.
[0004]
As a grinding hole drilling tool, as shown in FIG. 7A, a grinding hole drilling tool 31 in which a plurality of arc-shaped grinding portions 33 made of abrasive grains are attached to the tip of the rotating shaft 32 is proposed. Yes. Each grinding part 33 is provided at regular intervals and forms a plurality of grooves 35. Each groove part 35 supplies the cooling fluid supplied from the flow path 34 inside the rotating shaft 32 to the grinding part 33, and discharges the cooling water and the concrete grinding waste together through the groove part 35 ( For example, see Patent Document 1).
[0005]
However, as shown in FIG. 7B, the grinding and drilling tool 31 has a concrete core 37 formed inside the rotating shaft 32 (flow path 34) during grinding and drilling, and the work of removing the concrete core 37 is performed. It was necessary. In particular, in the small-diameter grinding drilling, the work time for removing the concrete core 37 becomes longer than the grinding drilling work time, and the work efficiency of the grinding drilling is lowered.
[0006]
In order to solve the above-described problem, a so-called non-core drill has been proposed in which a concrete core does not occur during grinding drilling. As an example of such a non-core drill, as shown in FIGS. 6 (a) and 6 (b), the flat end surface 22a of the rotating shaft 22 having a flow path 24 is made hollow except for the cooling fluid ejection holes 24a, A grinding part 23 having a groove part 25 is attached to the flat end face 22a, and an ejection hole is formed in an oblique direction from a position eccentric from the center of the rotary shaft 22 (tip face of the flow path 24) toward the peripheral position of the flat end face 22a. There has been proposed a grinding and drilling tool 21 in which the front end surface of the flow channel 24 is formed in a conical shape so that the front end surface of the flow channel 24 and the axis of the ejection hole 24a are perpendicular to each other. This grinding drilling tool 21 prevents the concrete core scraps from entering the ejection holes 24a by shifting the ejection holes 24a from the center of the rotary shaft 22. Moreover, the cooling fluid is supplied to the outer peripheral portion of the grinding portion 23, which is the portion with the highest grinding resistance, by forming the ejection holes 24a in an oblique direction. Furthermore, by forming the front end surface of the flow path 24 in a conical shape, the cooling fluid can be smoothly introduced from the flow path 24 to the ejection holes 24a. (For example, refer to Patent Document 2).
[0007]
[Patent Document 1]
Japanese Patent No. 2800475 (first column, left column, lines 2 to 12, lines 4 and 6)
[Patent Document 2]
JP 2001-232628 (paragraph numbers [0010], [0011], [0013], [0027], [0028], FIG. 3)
[0008]
[Problems to be solved by the invention]
However, in the grinding and drilling tool 21 shown in FIGS. 6A and 6B, even if the cooling fluid ejection hole 24 a is deviated from the center of the rotating shaft 22, the amount of eccentricity is small, and the grinding part 23. Therefore, it is impossible to completely prevent the concrete core chips crushed by the groove 25 of the grinding part 23 from entering the ejection hole 24a, and clogging occurs. appear. Further, due to this clogging, the cooling fluid is not efficiently supplied to the grinding part 23, and sufficient grinding and drilling ability cannot be obtained. As a result, there is a problem that it takes a long time for the grinding drilling, the working efficiency of the grinding drilling is lowered, and the abrasive grains of the grinding part 23 are also easily dropped and the life of the grinding drilling tool 21 is shortened. Further, it is necessary to form holes in two places (the flow path 24 and the ejection hole 24a) of the rotary shaft 22, and there is a problem that the processing is complicated and the operation cost is increased.
[0009]
Therefore, the present invention was created to solve such problems, and an object of the present invention is to provide a grinding drilling tool that can extend the life of the grinding drilling tool and does not reduce the working efficiency of the grinding drilling. There is.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 includes a rotating shaft that is hollow and has a flow path, and a grinding portion that is attached to a tip surface of the rotating shaft and has a groove that communicates with the flow path. The groove portion has a tip including a central axis of the grinding portion so that at least a part of a circumference of a cross section perpendicular to the axial direction of the grinding portion is opened. A protrusion that protrudes into the groove portion from the bottom of the groove portion to a height that hides the flow path of the rotating shaft when viewed from the front end surface of the grinding portion. A grinding drilling tool in which an inclined surface inclined toward the flow path is formed on the base end surface side of the protruding portion .
[0011]
According to the above configuration, the grinding part is rotated so that at least a part of the grinding part in the circumferential direction is opened when the grinding part rotates with the rotation of the rotating shaft during grinding drilling to grind, for example, concrete as a member to be ground. The concrete core having the diameter of the groove width is ground so as to be gradually formed in the groove portion formed from the distal end surface to the proximal end surface. Then, as the drilling of the member to be ground proceeds (with the pressing of the grinding drilling tool against the member to be ground), the concrete core in the groove moves in the circumferential direction by the rotation of the grinding part, and the movement In between, it is crushed small by the crushing action surface of the groove. And the crushed concrete core is discharged | emitted via a groove part in the circumferential direction of a grinding part with the cooling fluid supplied from the flow path of a rotating shaft and supplied via a groove part. In addition, when the concrete core moves in the groove portion toward the base end surface of the grinding portion, the concrete core cannot move any more due to the protruding portion.
[0012]
Moreover, by having the protrusion part which protrudes in a groove part in the base end surface vicinity of a groove part, the concrete core formed in the groove part hits a protrusion part, and is crushed small. And the crushed concrete core is discharged | emitted through a groove part in the circumferential direction of a grinding part with a cooling fluid. Further, the cooling fluid supplied through the flow path inside the rotating shaft hits the protruding portion, flows in the circumferential direction of the grinding portion, and is supplied to the outer peripheral portion of the tip surface of the grinding portion having the highest grinding resistance.
[0014]
Furthermore, an inclined surface that is inclined toward the flow path is formed on the base end surface side of the protrusion, so that the cooling fluid supplied through the flow path inside the rotating shaft is along the inclined surface of the protrusion. Thus, it flows in the circumferential direction of the grinding part and is easily supplied to the outer peripheral part of the tip surface of the grinding part having the highest grinding resistance.
[0015]
The invention according to claim 2 is a grinding drilling tool formed so that a groove width of the groove portion increases in a circumferential direction of the grinding portion in a cross section orthogonal to the axial direction of the grinding portion. It is composed.
[0016]
According to the said structure, by forming so that the groove width of a groove part may expand, the area which contributes to crushing of a concrete core becomes large, crushing is accelerated | stimulated, and the discharge property of the crushed concrete core also improves. .
[0017]
According to a third aspect of the present invention, in the cross section parallel to the axial direction of the grinding part, the groove depth of the groove part is formed so as to decrease from the front end surface to the base end surface of the grinding part. It is configured as a drilling tool.
[0018]
According to the above configuration, the groove depth of the groove portion is formed so as to be reduced from the front end surface toward the base end surface, thereby increasing the area contributing to crushing of the concrete core, promoting crushing, and crushing The discharged property of the concrete core is also improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view showing the configuration of a grinding drilling tool, FIG. 2A is a front side view of the grinding drilling tool, FIG. 1B is a proximal side view, and FIG. 3 is a cross-sectional view taken along line AA in FIG. Fig.4 (a) is the schematic which shows the operation state of a grinding part, (b)-(d) is a front end end view which shows other embodiment of a grinding part.
[0020]
As shown in FIG. 1, a grinding drilling tool 1 includes a rotating shaft 2 that is hollow and has a flow path 4, and a grinding section that is attached to the tip surface of the rotating shaft 2 and has a groove portion 5 that communicates with the flow path 4. 3. Each configuration will be described below.
[0021]
(Rotating shaft 2)
As shown in FIG. 5, the rotating shaft 2 has a base end portion attached to the tip end of the motor shaft 43 of the drilling machine 41 by screw fitting via a fastening portion 44. Moreover, the attachment method to the motor shaft 43 is not limited to the structure of FIG. 5, The well-known method which can transmit the rotation of the motor shaft 43 to the rotating shaft 2 of the grinding drilling tool 1 efficiently is used. Therefore, in FIG. 1, the rotating shaft 2 is configured by a substantially cylindrical body having an outer diameter of about 3 to 20 mm, but the shape and size of the rotating shaft 2 are appropriately selected depending on the configuration of the drilling machine to be used. A prismatic body may be used, and an uneven portion for fitting with the motor shaft may be formed on the outer peripheral surface. In addition, it is preferable that the rotating shaft 2 is comprised with metals, such as stainless steel.
[0022]
Moreover, as shown in FIG. 3, the flow path 4 formed in the inside of the rotating shaft 2 is formed so as to penetrate the central position of the rotating shaft 2 from the base end surface 2b to the front end surface 2a along the axial direction. . In FIG. 3, it is a straight channel 4 and the outer diameter of the channel 4 is not changed. However, the channel 4 is a tapered channel whose diameter is reduced or expanded from the proximal end surface 2b toward the distal end surface 2a. May be present (not shown).
[0023]
The ratio of the outer diameter of the flow path 4 to the outer diameter of the rotating shaft 2 is the type of the member to be ground (hard material such as concrete), the rotational speed of the rotating shaft 2 (grinding drilling tool 1) during grinding drilling, and the like. Is appropriately selected depending on the case, but 20 to 50% is preferable. If it is less than 20%, insufficient cooling of the grinding part 3 is likely to occur, and if it exceeds 50%, the strength of the rotating shaft 2 itself is insufficient, and the rotating shaft reaches the rotational speed (for example, high-speed rotating speed of about 2000 rpm). There is a risk of damage due to failure of 2
[0024]
By configuring the flow path 4 as described above, the cooling fluid W is supplied through the flow path 4 during grinding drilling, and passes through the groove portion 5 described later from the center position of the tip surface 2a of the rotating shaft 2 ( It is sprayed toward the outer periphery of the grinding part 3 (along the protrusion 6). As the cooling fluid W, water, oil, compressed air or the like is preferable, and a mixture of grinding fluid may be used.
[0025]
(Grinding part 3)
A grinding part combines and hold | maintains an abrasive grain with a metal bond, and makes it a predetermined shape. As an abrasive grain, a diamond abrasive grain, a CBN abrasive grain, etc. can be used, and the average particle diameter of an abrasive grain is about 350-600 micrometers, and is suitably selected by a to-be-ground member. As shown in FIGS. 1-3, the shape of the grinding part 3 is a substantially cylindrical shape, The outer diameter is suitably selected by the drilling diameter of the member to be ground, for example, about 5-30 mm. Further, the ground end surface 3 b of the grinding portion 3 is joined to the distal end surface 2 a of the rotating shaft 2 by integral molding or brazing.
[0026]
In addition, the grinding section 3, as shown in FIGS. 1 to 3, the groove portion 5 so that at least a portion circular circumference of the cross section perpendicular to the axial direction is opened is formed, the groove portion 5 grinding unit 3 from the front end surface 3a to the base end surface 3b at a depth including the central axis 3.
[0027]
Thereby, as shown in FIG. 4A, the diameter of the concrete core 7 generated during grinding drilling is larger than that of the concrete core 37 generated by the conventional grinding drilling tool 31 (see FIG. 7B). Get smaller. Then, as shown in FIG. 3, the concrete core is moved in the circumferential direction by the rotation of the grinding portion 3, and is crushed small by the crushing action surface 5 a of the groove portion 5 during the movement. Together with the cooling fluid W supplied from the flow path 4 of the rotating shaft 2, it is discharged in the circumferential direction of the grinding part 3. As a result, the concrete core does not remain at the time of grinding drilling as in the prior art, and the work for removing the concrete core is not required, so that the working efficiency of the grinding drilling does not decrease.
[0028]
Further, as shown in FIG. 2A, the groove portion 5 is formed with a square groove along the diameter direction in the center portion of the tip surface 3a so that one of the circumferences of the grinding portion 3 is opened. (B) As shown in FIG. 3, it forms in the linear form from the front end surface 3a to the base end surface 3b along the axial direction of the grinding part 3. As shown in FIG. However, the groove portion 5 is not particularly limited as long as it has a crushing action surface 5a and can cool the grinding portion 3 with a cooling fluid W that communicates with the flow channel 4 and is supplied from the flow channel 4.
[0029]
For example, as shown in FIGS. 1 to 3, the groove portion 5 has a groove width d larger than the outer diameter of the flow passage 4 so that all of the flow passage 4 opens into the groove portion 5 on the base end surface 3 b of the grinding portion 3. In the width, the groove depth is set to a predetermined depth, but the groove width d and the groove depth h may be set to dimensions that allow a part of the flow path 4 to be opened. As shown in (b), the groove 5 may be formed at a position shifted from the center (diameter direction) of the tip surface 3 a of the grinding part 3. Further, as shown in FIG. 4C, the groove 5 may be formed so that the grinding part 3 is divided into two in the axial direction in which two places on the circumference of the grinding part 3 are opened.
[0030]
Further, the shape of the groove portion 5 is not limited to a square groove, and may be a V-shaped groove or a U-shaped groove (not shown), but as illustrated in FIGS. A shape in which a tapered surface is formed so as to expand toward the circumferential direction of the grinding part 3 is preferable, and this increases the area that contributes to the crushing of the concrete core and promotes crushing. Emissions are also improved. Further, as shown in FIG. 4D, the taper surface (inclination angle is, for example, about 10 degrees) may be only on one side, thereby reducing the cost of the mold.
[0031]
Moreover, the form of the groove part 5 is not limited to the linear groove part 5, and the form formed so that the groove depth h decreases from the front end surface 3a of the grinding part 3 toward the base end face 3b is preferable (FIG. 3). Thus, the area contributing to the crushing of the concrete core is increased, the crushing is promoted, and the discharge performance of the concrete core waste is improved. Further, it may be a crank-shaped groove, a wavy groove, a spiral groove, or the like.
[0032]
Further, as shown in FIG. 3, the groove portion 5 has a groove portion 5 in the vicinity of the base end surface up to a height that hides the flow path 4 of the rotating shaft 2 from the bottom portion of the groove portion 5 when viewed from the front end surface 3 a of the grinding portion 3. It has the protrusion part 6 which protrudes inside. Thereby, the concrete core formed in the groove part 5 hits this protrusion part 6, and is crushed small. Further, the cooling fluid W supplied through the flow path 4 inside the rotating shaft 2 hits the protruding portion 6, and the outflow direction of the cooling fluid W becomes the circumferential direction of the grinding portion 3. The crushed concrete core scraps are discharged along the flow of the cooling fluid W through the groove portion 5 in the circumferential direction of the grinding portion 3 and do not enter the flow path 4. As a result, the concrete core does not remain in the flow path 4 at the time of grinding drilling as in the prior art, and it is not necessary to remove the concrete core, so that the working efficiency of the grinding drilling does not decrease.
[0033]
In addition, since the cooling fluid W that has flowed out in the circumferential direction of the grinding unit 3 is efficiently supplied to the portion of the grinding unit 3 with high grinding resistance (the outer peripheral portion of the tip surface 3a of the grinding unit 3), Cooling efficiency is improved. As a result, the grinding drilling capability of the grinding part 3 is not lowered, the working efficiency of the grinding drilling is not lowered, and the life of the grinding drilling tool is extended.
[0034]
Further, the projecting portion 6 is formed so as to be in contact with the base end face 3b of the grinding portion 3, but the crushing action for crushing the concrete core that has moved in the groove portion 5 is small, and the crushed concrete. A position having a predetermined interval from the base end face 3b of the grinding part 3 (if it has a discharging action for discharging the core waste and a regulating action for regulating the outflow direction of the cooling fluid W in the circumferential direction of the grinding part 3) It can be formed in the vicinity of the base end face of the groove 5.
[0035]
In addition, the cross-sectional shape of the protruding portion 6 is such that the surface having the crushing action and discharging action (crushing / discharging face 6a) is formed on the tip face 3a side of the grinding part 3 in a cross section parallel to the axial direction of the grinding part 3. The surface (inclined surface 6b) having the restricting action and the discharging action is formed on the base end face 3b side of the grinding portion 3, and has a substantially triangular shape. However, as long as it has the above-described crushing action of the concrete core, the discharging action of the concrete core waste, and the regulating action in the outflow direction of the cooling fluid W, it is not limited to a substantially triangular shape, for example, has a trapezoidal shape. May be.
[0036]
Further, the surface having the regulating action and the discharging action formed on the base end side of the projecting portion 6 is formed as an inclined surface 6b that is inclined toward the flow path 4, so that the cooling fluid W is supplied to the grinding portion. 3 flows in the circumferential direction and is easily supplied to the outer peripheral portion of the front end surface 3a. As a result, the cooling efficiency and the grinding drilling ability of the grinding part 3 are further improved, and the working efficiency of the grinding drilling is not lowered. Moreover, the lifetime of the grinding drilling tool 1 is prolonged. Furthermore, it is possible to further prevent the concrete core waste from flowing into the flow path 4.
[0037]
In addition, the inclination angle θ of the inclined surface 6 b of the protruding portion 6 is determined from the supply amount of the cooling fluid W from the flow path 4, the cooling efficiency at the outer peripheral portion of the grinding portion 3, and the discharge efficiency of the concrete core waste in the groove portion 5. For example, it is preferably set to about 45 degrees. Further, the crushing / discharging surface 6a of the protruding portion 6 is also formed perpendicular to the axial direction of the groove portion 5 in FIG. 3, but is inclined toward the flow path 4 in consideration of the discharging property of the concrete core scrap. You may do it. Even if the crushing / discharging surface 6 a is inclined toward the flow path 4, the concrete core waste does not flow into the flow path 4 due to the flow of the cooling fluid W in the circumferential direction of the grinding portion 3.
[0038]
Next, a method for using the grinding and drilling tool 1 of the present invention will be described. As shown in FIG. 5, the grinding drilling tool 1 of the present invention attaches the grinding drilling tool 1 to a motor shaft 43 provided inside the casing 42 of the drilling machine 41 via a fastening portion 44. Next, the collection chamber 45 provided at the tip of the casing 42 is brought into contact with the concrete wall K, and the tip of the grinding drilling tool 1 is aligned with the drilling position.
[0039]
Next, as shown in FIG. 3, a cooling fluid W such as air or water is supplied into the flow path 4 from the base end surface 2 b of the rotary shaft 2 of the grinding drilling tool 1, and the flow path is flowed at the distal end surface 2 a of the rotary shaft 2. The cooling fluid W is supplied into the grinding part 3 through the groove part 5 communicating with the part 4. Then, the grinding drilling tool 1 is rotated at a high speed of, for example, about 2000 rpm while jetting the cooling fluid W in the circumferential direction of the grinding part 3 along the protruding part 6 formed in the vicinity of the base end face of the groove part 5. Then, the concrete is ground by the tip surface 3a of the grinding part 3 so as to form the concrete core 7 in the groove part 5 (see FIG. 4A).
[0040]
Next, when the grinding drilling tool 1 is pressed against the concrete wall K at a feed rate of, for example, about 7 mm / min, the concrete core in the groove portion 5 moves in the circumferential direction of the grinding portion 3 by the rotation of the grinding portion 3, During the movement, the crushing surface 5a (see FIG. 4 (a)) is crushed into small concrete core waste, and the concrete core waste is rotated along with the cooling fluid W flowing along the groove 5 and the grinding portion 3 is rotated. Is discharged in the circumferential direction of the grinding part 3. Note that the concrete core 7 does not move any more because the tip portion of the concrete core 7 is in contact with the protruding portion 6 in the groove portion 5, and is crushed by the protruding portion 6 (crushing / discharging surface 6a). 4 is not blocked. The cooling fluid W that has flowed out in the circumferential direction of the grinding part 3 flows along the outer periphery of the grinding part 3 and is supplied to the outer peripheral part of the tip surface 3a having the highest grinding resistance, thereby cooling the grinding part 3 and grinding drilling. Increase ability.
[0041]
Then, as shown in FIG. 5, the concrete core waste flowing into the collection chamber 45 is discharged together with the cooling fluid while being sucked by the suction pipe 46, and a small hole H is formed in the concrete wall K.
[0042]
In addition, this invention is not limited to the said description and drawing, A various change can be added in the range which does not deviate from the summary of invention.
[0043]
【The invention's effect】
As described above, in the present invention, the groove is such that said at least part of a circle of the cross section circumference which is perpendicular to the axial direction of the grinding portion is opened, the distal end surface at a depth that contains the central axis of the grinding unit To the base end surface, and in the vicinity of the base end surface of the groove portion, a protrusion protruding into the groove portion from the bottom of the groove portion to a height that hides the flow path of the rotating shaft when viewed from the front end surface of the grinding portion. Thus, it is possible to provide a grinding drilling tool that can extend the life of the grinding drilling tool and that does not reduce the working efficiency of the grinding drilling.
[0044]
Further, in the present invention, an inclined surface that is inclined toward the flow path is formed on the base end side of the protruding portion, so that the life of the grinding drilling tool can be further increased. It was possible to provide a grinding drilling tool with improved work efficiency.
[0045]
Further, in the present invention, there is provided a grinding drilling tool in which the working efficiency of grinding drilling is further improved by forming the groove width of the groove part so as to increase in the circumferential direction of the grinding part. I was able to.
[0046]
Further, in the present invention, a grinding drilling tool in which the working efficiency of grinding drilling is further improved by forming the groove depth of the groove part so as to decrease from the distal end surface to the proximal end surface of the grinding unit. Could be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a configuration of a grinding drilling tool of the present invention.
2A is a front side view of a grinding drilling tool of the present invention, and FIG. 2B is a base end side view.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
4A is a schematic view showing an operating state of a grinding part of the present invention, and FIGS. 4B to 4D are end end views showing other embodiments of the grinding part. FIG.
FIG. 5 is a partial cross-sectional view of a tip portion of a punching machine.
6A is a front end side view showing a configuration of a conventional grinding drilling tool, and FIG. 6B is a sectional view taken along line BB in FIG. 6A.
7A is a perspective view of a conventional grinding drilling tool, and FIG. 7B is a schematic view showing an operating state of a grinding part.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Grinding drilling tool 2 Rotating shaft 2a, 3a Front end surface 2b, 3b Base end surface 3 Grinding part 4 Flow path 5 Groove part 5a Crushing action surface 6 Projection part 6a Crushing / discharge surface 6b Inclined surface 7 Concrete core d Groove width h Groove depth θ Inclination angle W Cooling fluid

Claims (3)

A rotating shaft hollow and having a flow path;
A grinding drilling tool provided with a grinding part attached to a tip surface of the rotating shaft and having a groove part communicating with the flow path;
The groove portion is formed from the distal end surface to the proximal end surface at a depth including the central axis of the grinding portion so that at least a part of the circumference of the cross section orthogonal to the axial direction of the grinding portion is opened.
In the vicinity of the base end surface of the groove portion, when viewed from the front end surface of the grinding portion, it has a protruding portion that protrudes into the groove portion to a height that hides the flow path of the rotation shaft from the bottom portion of the groove portion ,
An inclined surface that is inclined toward the flow path is formed on the base end surface side of the protrusion . 2. The grinding hole according to claim 1 , wherein a groove width of the groove portion is formed to increase in a circumferential direction of the grinding portion in a cross section orthogonal to the axial direction of the grinding portion. tool. In a cross section parallel to the axial direction of the grinding part, the groove depth of the groove, according to claim 1 or claim, characterized in that it is formed so as to reduce towards the proximal end surface from the distal end surface of the grinding part Item 3. A grinding drilling tool according to Item 2 .

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