JP2005014360A - Drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill of simple structure used for processing an object to be processed to form a hole, of which the bottom part is diametrically expanded, to the object to be processed and capable of efficiently performing the processing of a preparative hole, the diametrically expanding processing of the hole bottom part and the internal cleaning of the hole. <P>SOLUTION: In the drill 200 wherein a shank part 211 is provided to a drill main body 210 integrally or separately, the drill main body 210 has the flange part 207 provided thereto on the side of the shank part, a cutting blade part 201 provided to the leading end side thereof, a predetermined first taper part 204 and a predetermined second taper part 206. The flange part 207 on the side of the shank part is provided with a predetermined third taper part 207a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to a drill for machining a hole whose bottom is enlarged in a workpiece, and in particular, the drill body has first and second tapered portions and a third shank portion-side collar portion. The present invention relates to a drill provided with a tapered portion.
[0002]
[Prior art]
In general, when anchor bolts or the like are driven into a workpiece such as concrete to fix the workpiece to concrete or the like, as shown in FIG. To fix the fixed object 3 to the workpiece 1 by driving the anchor bolt 4 with the bolt head 4a having an enlarged diameter into the hole 2 having the enlarged diameter bottom portion 2a provided in the workpiece 1. (For example, refer nonpatent literature 1.).
[0003]
2. Description of the Related Art Conventionally, as a drill used to process a hole having an enlarged diameter bottom portion, for example, as shown in FIG. 2, a drill 100 in which a shank portion (not shown) is provided on a drill body 110, In general, a drill 100 having a bulging portion 120 and a shank portion side collar portion 131 having a concavely curved end surface has been proposed. The bulging portion 120 has a distal end side cutting edge portion 101 and a through hole 110a for suctioning chips generated at the cutting edge portion 101. The drill 100 further includes a bell-shaped suction adapter 133 that sucks the chips through the through-hole 110a, and a support plate 132 having a spherical sliding surface.
[0004]
Then, after machining the pilot hole 20b with the drill 100, the concave end surface of the shank portion side collar portion 131 is slid on the sliding surface of the support plate 132, and the drill 100 is swiveled using the bulging portion 120 as a swivel support portion. By operating, the diameter of the bottom of the hole 20 is increased 20a (see, for example, Patent Document 1).
[0005]
[Non-Patent Document 1]
Miyanaga Co., Ltd., “Undercut Anchor System”, [online], 1998, [Search May 28, 2003], Internet <URL: http: // www. Miyanaga. co. jp / cat-jp / ansex / index. html>
[Patent Document 1]
Japanese Patent Laid-Open No. 5-200731 (page 2-3, FIG. 1)
[0006]
[Problems to be solved by the invention]
However, the conventional drill 100 has a problem that the structure is complicated because the support plate 132 is required, the manufacturing is not easy, and the manufacturing cost is increased.
[0007]
[Means for Solving the Problems]
A drill according to the present invention for solving the above-mentioned problem is a drill in which a shank portion is provided integrally or separately in a drill body, and a hole whose bottom is enlarged is formed on a workpiece. In the drill, the drill main body includes a first cutting edge portion, a shank portion side collar portion, and a first taper provided between the cutting edge portion and the collar portion on the cutting edge portion side and the collar portion side, respectively. And a shank portion side collar portion, the diameter of the shank portion side flange portion is gradually reduced in the direction of the cutting edge portion, that is, in the tip end direction on the side surface on the cutting edge portion side, and A third taper portion that is in contact with the surface is provided, and each of the first taper portion and the second taper portion has a shape in which the diameter gradually decreases and expands in the tip direction, It is possible to contact the circumferentially symmetric position portion of the circumference, When the taper portion, the second taper portion, and the third taper portion come into contact with the inner periphery of the hole, the inner periphery, and the surface of the workpiece, the tip side cutting blade portion rotates. The outer diameter portion is located radially outward from the inner diameter of the hole by a predetermined dimension.
[0008]
Preferably, the first angle of the taper surface of the first taper portion with respect to the longitudinal axis of the drill body, the second angle of the taper surface of the second taper portion with respect to the axis, and the third taper portion The third angle of the tapered surface with respect to the direction perpendicular to the axis is substantially the same angle.
[0009]
Preferably, the drill body has a first reduced diameter portion between the first tapered portion and the second tapered portion.
[0010]
Preferably, the drill body has a second reduced diameter portion between the cutting edge portion and the first taper portion.
[0011]
Preferably, each of the first taper portion and the second taper portion has at least one circumferential groove extending in the circumferential direction.
[0012]
Preferably, the rotational outer diameter of the cutting edge portion gradually increases in the distal direction from the reduced diameter portion of the first tapered portion.
[0013]
Further preferably, the rotational outer diameter of the tip end portion of the cutting edge portion gradually decreases from the tip end portion of the cutting edge portion toward the tip end.
[0014]
A drill according to the present invention for solving the above-described problems is a drill in which a shank portion is provided integrally or separately in a drill body, and a hole whose bottom is enlarged is formed on a workpiece. In the drill to be processed, the drill body includes a shank portion side collar portion, a tip side cutting edge portion, and a tapered portion provided on the collar portion side between the collar portion and the cutting edge portion, and the taper portion. The portion has a shape whose diameter gradually increases in the direction of the cutting edge, and can contact the inner periphery of the hole at the time of processing. When the tapered portion contacts the inner periphery of the hole at the time of processing Further, the rotating outer diameter portion of the tip side cutting edge is located radially outward from the inner diameter of the hole by a predetermined dimension.
[0015]
Preferably, the drill body has a reduced diameter portion between the cutting edge portion and the tapered portion.
[0016]
Preferably, the drill body includes a through hole that opens at a tip thereof and extends to a predetermined position in an axial direction and opens on the shank part side of the collar part or the collar part of the drill body.
[0017]
Preferably, there are two or more tip side opening portions, and at least one tip side opening portion is provided on each side of the tip portion of the cutting blade portion protruding toward the tip of the drill body.
[0018]
Preferably, the drill body is fitted and fixed to the flange portion or the shank portion side portion corresponding to the opening on the shank portion side of the drill body, and chips generated at the cutting blade portion are passed through the through hole. A suction adapter for sucking is further provided.
[0019]
Preferably, the shank portion is provided separately from the drill body, and has a second locking means for engaging the first locking means of the shank portion at the rear end of the drill body.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
A drill according to the present invention will be described with reference to FIGS.
[0021]
In FIG. 3, a drill 200 according to the present invention is generally made of a material that provides desired strength such as hardened steel, has a drill body 210 and a shank portion 211 that is provided integrally with the body 210, and is made of concrete or the like. The hole 2 whose hole diameter is expanded 2a is processed on the workpiece 1.
[0022]
The shank portion 211 is not necessarily provided integrally with the drill main body 210. For example, as shown in FIG. 4, the shank portion 211 is engaged with the second locking means 209e provided at the rear end of the drill main body. May be provided separately from the drill main body 210. In the figure, the first locking means 211a and the second locking means 209e are a female screw and a male screw, respectively, but may be, for example, a concave section and a convex section having a polygonal cross section that can be engaged with each other.
[0023]
The drill body 210 generally includes a cutting edge part 201, a cutting edge part taper part 204 as a first taper part, a constriction part 205 as a first reduced diameter part, and a flange part side taper as a second taper part. Part 206, shank side collar part 207, body part 208, and suction adapter holding part 209.
[0024]
The cutting edge portion 201 is made of a material that provides desired strength and hardness, such as cemented carbide, and is brazed to the distal end portion 202 of the drill body 210 so as to form projecting portions 201a and 201b that project outward and distally. Is done. The rotational outer diameter of the cutting blade part 201 (201a) gradually increases in the distal direction from the distal-side reduced diameter part of the cutting blade-side tapered part 204, and the rotational outer diameter of the cutting blade part distal-end part 201b is It gradually shrinks from the end on the tip side toward the tip. In addition, the cutting blade part 201 may be provided integrally with the drill main body 210, such as cutting directly from the drill main body 210, for example. Further, the cutting edge portion 201 does not need to be provided with the protruding portion 201b at the tip end portion 202 of the drill body. In this case, the drill 200 is not used for processing the prepared hole 2a, and the bottom portion of the hole 2 is expanded in diameter 2a. Used only to
[0025]
The cutting edge portion side taper portion 204 and the collar portion side taper portion 206 are provided between the cutting edge portion 201 and the collar portion 207 on the cutting edge portion 201 side and the collar portion 207 side, respectively. Here, each of the cutting edge portion side taper portion 204 and the flange portion side taper portion 206 has a shape in which the diameter is gradually reduced and expanded in the distal direction, and has a plurality of circumferential grooves 204a and 206a extending in the circumferential direction. . The circumferential grooves 204a and 206a may be one or may not be present. Further, both the taper portions 204 and 206 may have concave portions (for example, dimple shapes) on the surfaces instead of the circumferential grooves 204a and 206a.
[0026]
As shown in FIG. 3, the constricted portion 205 is provided between the cutting edge portion side tapered portion 204 and the flange portion side tapered portion 206, and has an outer diameter smaller than the maximum outer diameter of both the tapered portions 204 and 206.
[0027]
The drill main body 210 has a chip escape portion 203 as a second reduced diameter portion between the cutting edge portion 201 and the cutting edge portion side tapered portion 204. As shown in FIG. 3, the outer diameter of the chip escape portion 203 has an outer diameter smaller than the outer diameter on the extension line of the tapered surface of the cutting edge portion side taper portion 204, whereby the shank defining the clearance 203a. The part side collar part 207 is provided with a surface contact taper part 207a as a third taper part whose diameter gradually decreases in the direction of the cutting edge part, that is, in the front end direction, on the side surface on the cutting edge part side. The surface contact taper portion 207a is not necessarily required.
[0028]
As shown in FIG. 3, the first angle of the taper surface of the cutting edge portion side taper portion 204 with respect to the longitudinal axis of the drill body 210, the second angle with respect to the axis of the taper surface of the collar portion side taper portion 206, and the surface The third angle with respect to the direction perpendicular to the axis of the tapered surface of the contact taper portion 207a is substantially the same angle α.
[0029]
The outer diameter of the suction adapter holding portion 209 is smaller than the outer diameter of the body portion 208, thereby defining a shoulder portion 209c as shown in FIG. An O-ring groove 209d is provided at a predetermined position of the holding portion 209, and the O-ring 218 is fitted into the groove 209d.
[0030]
The vertical hole 209a extends on the central axis of the drill body 210 in FIG. 3 and forms openings 202b and 202b ′ on both sides of the cutting edge tip 201b at the drill body tip 202 (see FIG. 5). In addition, the suction adapter holding portion 209 communicates with a lateral hole 209b extending in a direction orthogonal to the axis. Here, the number of the front end side openings 202b and 202b ′ may be one, or three or more. In addition, as long as the openings 202b and 209b are formed in the drill main body front end portion 202 and the holding portion 209, the path of the through hole may not be strictly in the axial direction and the axial orthogonal direction.
[0031]
As shown in FIG. 3, the suction adapter 215 covers both ends of the cylindrical portion 213 with a pair of ring-shaped discs 212, and a pipe connection portion 214 is attached to one side, and the lower disc 212 is a shoulder portion. It fits to the holding part 209 so that it may contact | abut to 209c. The suction adapter 215 is fixed in the axial direction by an O-ring 218 via a holding member 217 fitted to the holding portion 209 and is rotatable about the shaft. As a result, the chips generated at the cutting edge portion 201 are sucked by a dust collector (not shown) connected to the pipe connection portion 214 through the through holes 209a and 209b. The pair of discs 212 of the suction adapter 215 is made of resin in order to improve sliding, and the cylindrical portion 213 is preferably made of aluminum for weight reduction, but may be made of other materials.
[0032]
The lateral hole 209b may be provided in the collar part 207, and the suction adapter 215 may be fitted and fixed to the collar part 207 in a fitting manner.
[0033]
Then, the usage method of the drill 200 is demonstrated.
[0034]
A pilot hole 2b that forms a predetermined angle (for example, vertical) with respect to the surface 1a of the workpiece 1 is processed by a drill 200 connected to an electric motor (not shown) via a shank portion 211. When machining the pilot hole 2b, the collar portion 207 serves as a stopper that determines the depth of the pilot hole 2b. Further, the diameter of the pilot hole 2b is substantially equal to the maximum outer diameter of the cutting edge portion 201.
[0035]
By the way, since the hole 2 for the anchor bolt 4 (see FIG. 1) having such a diameter expanding head is deeper than a hole for a normal anchor bolt, a large amount of chips are generated during the processing. There is a problem that the drill 200 cannot be removed from the hole 2 unless the chips are sufficiently removed. Further, when the anchor bolt 4 is driven into the hole 2 while the chips remain in the hole 2, the anchor bolt 4 slips from the hole 2 by the chips remaining between the anchor bolt 4 and the inner peripheral surface of the hole 2. There is a problem that it becomes easy to come off and the desired pulling strength cannot be obtained. According to the drill 200, since the chips are sucked by a dust collector (not shown) simultaneously with the processing, it is not necessary to separately provide a hole bottom cleaning work process after the processing is completed (or processing is appropriately interrupted). Processing operations can be simplified.
[0036]
After processing the pilot hole 2b, the collar portion side taper portion 206 and the surface contact taper portion 207a are brought into contact with the inner periphery of the pilot hole 2b and the surface 1a of the workpiece 1, respectively, and the drill 200 with respect to the longitudinal axis of the pilot hole 2b. Positioning. At this time, the cutting edge portion side taper portion 204 contacts the diametrically symmetrical position portion below the inner periphery of the hole 2b with respect to the contact position of the collar portion side taper portion 206. In addition, the pilot hole 2b does not necessarily need to be processed accurately in the vertical direction with respect to the surface of the workpiece 1. Further, the surface contact taper portion 207a may not contact the surface 1a of the workpiece 1.
[0037]
After the positioning of the drill 200, the flange portion side taper portion 206, the surface contact taper portion 207a, and the cutting edge portion side taper portion 204 are respectively connected to the inner circumference of the pilot hole 2b, the surface 1a of the workpiece 1 and the pilot hole 2b. The drill 200 is swung (grinded) in the pilot hole 2b while being along the inner periphery. Here, the provision of the constricted portion 205 can reduce the contact area between the drill body 210 and the inner periphery of the hole 2, and the frictional force generated between the drill body 210 and the inner periphery of the hole 2 during the turning operation. Since (turning resistance) can be reduced, a smooth turning operation is possible. Further, since the circumferential grooves 206a and 204a are provided in the flange side taper portion 206 and the cutting edge side taper portion 204, respectively, the taper surface generated during the turning operation and the inner circumference of the hole 2 as described above. The frictional force between the two is reduced.
[0038]
As a result of the sufficient turning operation, as shown in FIG. 3, the cutting blade portion 201 (201a) forms the enlarged diameter portion 2a in which the bottom of the hole 2 is enlarged. At this time, the drill 200 is positioned with respect to the axis of the hole 2 by the contact between the cutting edge portion side taper portion 204 and the inner periphery of the hole 2 and the contact between the collar portion side taper portion 206 and the inner periphery of the hole 2. Then, the inner diameter of the enlarged diameter portion 2a is defined in combination with the taper angle of the rotating outer diameter of the cutting edge portion 201a, and the contact between the surface contact tapered portion 207a and the workpiece surface 1a in the hole 2 of the enlarged diameter portion 2a. An axial depth position is defined, and a desired enlarged diameter portion 2a is formed.
[0039]
Here, when the pilot hole 2b having a substantially constant diameter is to be machined in a direction substantially perpendicular to the surface 1a of the workpiece 1, the first angle of the cutting edge portion tapered portion 204 as shown in FIG. The second angle of the flange side taper portion 206 and the third angle of the surface contact taper portion 207a are preferably substantially the same, but the diameter of the pilot hole 2b is not constant, or the pilot hole 2b Are not necessarily processed in the direction perpendicular to the surface 1a of the workpiece 1, these first to third angles are not necessarily the same.
[0040]
Also at the time of this diameter expansion processing, the chip generated during the processing is sucked by a dust collector (not shown) at the same time as the processing, as in the case of the above-mentioned pilot hole processing. As described above, the chips generated during the processing of the hole 2 are mainly sucked by a dust collector (not shown), but the chips that the dust collector cannot fully suck are the chip escape portion 203a and the constricted portion 205. (Of course, a part of the chips escapes outward from the upper part of the hole 2 through the constricted portion 205). Thereby, for example, even when the dust collector stops at the time of processing, it is possible to avoid a situation in which the chips are accumulated between the inner periphery of the hole 2 and the drill body 210 and the drill 200 does not come out of the hole 2. In some cases, the through holes 209a and 209b of the drill 200 and the adapter 215 are not necessarily provided, and the drill 200 has an enlarged bottom portion 2a due to the functions of the chip escape portion 203a and the constricted portion 205. It can function as a drill for machining the hole 2.
[0041]
Next, another embodiment of the drill according to the present invention will be described with reference to FIG.
[0042]
In FIG. 6, a drill 300 according to the present invention is a drill of a type that does not have the cutting edge portion side taper portion 204 and the surface contact taper portion 207 a in the drill 200 according to the first embodiment of the present invention. 3 are denoted by the same reference numerals, description thereof is omitted, and corresponding members are denoted by “300” instead of “200” in FIG. A constricted portion 305 as a reduced diameter portion of the drill 300 extends between the cutting edge portion 301 and the tapered portion 306.
[0043]
Since the method of using the drill 300 is generally the same as the method of using the drill 200, the description thereof is omitted. As shown in FIG. 6, positioning of the drill 300 with respect to the longitudinal axis of the pilot hole 2 b brings the tapered portion 306 into contact with the inner periphery of the pilot hole 2 b and the outer edge portion of the collar portion 307 on the surface 1 a of the workpiece 1. To contact. When positioning the drill 300, the outer edge portion of the collar portion 307 is not necessarily brought into contact with the workpiece surface 1a.
[0044]
[Effect of the present invention]
According to the drill of the present invention, the drill body is provided with a shank portion, and the drill body includes a shank portion side collar portion, a tip side cutting edge portion, and predetermined first to third tapered portions. Therefore, it has the following advantages.
[0045]
(1) As seen in the above prior art, the diameter of the bottom of the hole having a simple structure having only the first to third taper portions is increased without requiring an extra member such as a support plate. A drill can be provided for drilling holes.
[0046]
In other words, the drill is positioned with respect to the axis of the hole by the contact between the first taper portion and the inner periphery of the hole, and the contact between the second taper portion and the inner periphery of the hole, and the taper of the rotational outer diameter of the cutting edge portion. Combined with the angle, the inner diameter of the expanded diameter portion of the hole is defined, and the axial position of the expanded diameter portion in the hole of the expanded diameter portion is defined by contact between the third taper portion and the surface of the work piece, and the desired expanded diameter in the hole The part can be formed.
[0047]
(2) The first angle of the tapered surface of the first tapered portion with respect to the longitudinal axis of the drill body, the second angle of the tapered surface of the second tapered portion with respect to the axis, and the tapered surface of the third tapered portion. The third angle with respect to the direction perpendicular to the axis is substantially the same angle.
[0048]
As a result, when a prepared hole having a substantially constant diameter is machined in a direction substantially perpendicular to the surface of the workpiece, the drill of the present invention can machine a desired hole having an enlarged hole bottom.
[0049]
(3) The drill body has a first reduced diameter portion between the first tapered portion and the second tapered portion. As a result, chips generated during processing of the hole are released to the first reduced diameter portion (and are released to the outside of the hole via the first reduced diameter portion), and the chips are released inside the hole. By accumulating between the circumference and the drill body, it is possible to avoid a situation where the drill of the present invention does not come out of the hole. In addition, the contact area between the drill body and the inner circumference of the hole can be reduced, and the frictional force (swing resistance) generated between the drill body and the inner circumference of the hole during the turning operation of the drill of the present invention can be reduced. Operation is possible. Furthermore, if the direction of the drill with respect to the hole axis is shaken by the rotation or striking motion of the drill during drilling of the pilot hole of the present invention, the drill can be drilled before the entire first reduced diameter portion is inserted into the pilot hole. Since there is a space by the first reduced diameter portion between the main body and the edge of the opening of the hole, the direction of the drill can be easily corrected.
[0050]
(4) The drill body has a second reduced diameter portion between the cutting edge portion and the first taper portion. As a result, like the first reduced diameter portion, a space for the chips to escape is provided, and a situation in which the drill of the present invention does not come out of the hole after the processing can be avoided.
[0051]
(5) Each of the first tapered portion and the second tapered portion has at least one circumferential groove extending in the circumferential direction. Thereby, similarly to the first reduced diameter portion, the drill of the present invention can be smoothly turned in the hole.
[0052]
(6) The rotating outer diameter of the cutting edge portion gradually increases in the distal direction from the distal-side reduced diameter portion of the first tapered portion. Thereby, the drill of this invention can process the desired hole by which the hole bottom part was expanded in diameter.
[0053]
(7) The rotational outer diameter of the tip end portion of the cutting edge portion gradually decreases from the tip end portion of the cutting edge portion toward the tip end. Thereby, only with the drill of the present invention (without separately using a drill for preparing a prepared hole), the prepared hole can be processed and the diameter of the hole bottom can be increased.
[0054]
(8) According to another embodiment of the drill of the present invention, the drill body is provided with a shank portion, and the drill body includes a shank portion side collar portion, a distal end side cutting edge portion, and a predetermined taper. Part. Thereby, the drill of the simple structure for processing the hole by which the hole bottom part was diameter-expanded can be provided.
[0055]
(9) The drill body has a reduced diameter portion between the cutting edge portion and the tapered portion. As a result, as in the first embodiment, it is possible to provide a space for the chips to escape and avoid the situation in which the drill of the present invention cannot be removed from the hole. Further, the drill of the present invention can be smoothly turned. Furthermore, correction of the orientation of the drill of the present invention relative to the hole axis may be facilitated.
[0056]
(10) The drill body includes a predetermined through hole. Thereby, in-hole cleaning and the diameter expansion process of a hole bottom part can be performed only by the drill of this invention (without using a separate cleaning tool).
[0057]
(11) The plurality of opening portions on the tip side are provided on both sides of the tip portion of the cutting blade portion. Thereby, efficient in-hole cleaning is possible.
[0058]
(12) The predetermined suction adapter is fitted and fixed at a predetermined position of the drill body. Thereby, an external dust collector can be connected to this suction adapter, and chips generated during processing can be sucked.
[0059]
(13) The drill body has predetermined second locking means. Thereby, the drill of the present invention can be connected to various electric motors.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a state in which an anchor bolt having a diameter expanding head is driven into a workpiece.
FIG. 2 is a longitudinal sectional view of a conventional drill.
FIG. 3 is a longitudinal sectional view of a drill for explaining one embodiment of the drill of the present invention.
FIG. 4 is a front view of the shank portion of the drill of the present invention in FIG.
FIG. 5 is a bottom view of the drill of the present invention in FIG. 3;
FIG. 6 is a longitudinal sectional view of a drill for explaining another embodiment of the drill of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Structure 2 ... Hole 2a ... Expanded hole bottom part 4 ... Anchor bolt 100,200,300 which has a diameter-expansion head ... Drill 204 ... Cutting blade part side taper part 205 ... Neck part 206 ... Collar part side taper part 207 ... Shank side collar 207a ... Surface contact taper part 210 ... Drill body 211 ... Shank part 215 ... Suction adapter

Claims (13)

A drill (200) in which a shank portion (211) is integrally or separately provided on a drill body (210), the hole bottom of which is expanded (2a) with respect to the workpiece (1) In the drill for machining (2),
The drill body (210) is provided on the cutting edge side and the collar side between the leading edge side cutting edge part (201), the shank part side collar part (207), and the cutting edge part and the collar part, respectively. A first tapered portion (204) and a second tapered portion (206),
The diameter of the shank portion side collar portion (207) is gradually reduced in the direction of the cutting edge portion, that is, in the distal end direction on the side surface on the cutting edge portion side, and is contacted with the surface (1a) of the workpiece during processing. Three tapered portions (207a) are provided,
Each of the first taper portion (204) and the second taper portion (206) has a shape in which the diameter gradually decreases and expands toward the tip, and is symmetric in the diameter direction of the inner periphery of the hole (2) during processing. It is possible to contact the position part,
During the processing, the first taper portion (204), the second taper portion (206), and the third taper portion (207a) are respectively connected to the inner periphery, the inner periphery, and the covered portion of the hole (2). When contacting the surface (1a) of the workpiece, the rotational outer diameter portion of the tip side cutting edge (201) is located radially outward by a predetermined dimension from the inner diameter of the hole (2: 2b). A drill characterized by that. The drill according to claim 1, wherein
A first angle of the taper surface of the first taper portion (204) with respect to the longitudinal axis of the drill body (210); a second angle of the taper surface of the second taper portion (206) with respect to the axis; The third angle of the tapered surface of the third tapered portion (207a) with respect to the direction perpendicular to the axis is substantially the same angle (α). The drill according to claim 1 or 2,
The drill body (210) has a first reduced diameter portion (205) between the first taper portion (204) and the second taper portion (206). The drill according to any one of claims 1 to 3,
The drill body (210) has a second reduced diameter portion (203) between the cutting edge portion (201) and the first taper portion (204). The drill according to any one of claims 1 to 4,
The first taper part (204) and the second taper part (206) each have at least one circumferential groove (204a, 206a) extending in the circumferential direction. The drill according to any one of claims 1 to 5,
A drill characterized in that the rotating outer diameter of the cutting edge part (201: 201a) gradually increases in the distal direction from the reduced diameter part of the first tapered part (204). The drill according to any one of claims 1 to 6,
The drill characterized by the fact that the rotational outer diameter of the tip part (201b) of the cutting blade part gradually decreases from the tip side end part of the cutting blade part in the tip direction. A drill (300) in which a shank portion is provided integrally or separately with a drill body (310), and a hole (2) in which a hole bottom of the workpiece (1) is expanded (2a) In drills that machine
The drill body (310) includes a shank portion side collar portion (307), a distal end side cutting edge portion (301), and a tapered portion (306) provided on the collar portion side between the collar portion and the cutting edge portion. And
The tapered portion (306) has a shape in which the diameter gradually increases in the direction of the cutting edge, and can contact the inner periphery of the hole (2) during processing.
When the taper portion (306) contacts the inner periphery of the hole (2) during processing, the rotational outer diameter portion of the tip side cutting blade portion (301) is a predetermined dimension from the inner diameter of the hole (2: 2b). Located only radially outward,
A drill characterized by that. The drill according to claim 8,
The drill body (310) has a reduced diameter portion (305) between the cutting edge portion (301) and the tapered portion (306). The drill according to any one of claims 1 to 9,
The drill body (210, 310) has an opening (202b, 302b) at the tip thereof and extends to a predetermined position in the axial direction so as to open on the shank portion side of the collar portion (307) or the collar portion of the drill body. (209b) A drill having a through-hole (209a, 209b, 309a). The drill according to claim 10,
There are two or more tip side opening portions (202b, 202b ′, 302b), and at least one tip side opening portion protrudes toward the tip end of the drill body (210, 310). 201b, 301b), drills respectively provided on both sides. The drill according to claim 10 or 11,
The drill body (210, 310) is fitted and fixed to the collar portion (207, 307) or the shank portion side portion (209) corresponding to the shank portion side opening (209b) of the drill body (210, 310), and the cutting blade A drill characterized by further comprising a suction adapter for sucking chips generated in the parts (201, 301) through the through holes (209a, 209b, 309a). The drill according to any one of claims 1 to 12,
The shank portion (211) is provided separately from the drill body (210, 310), and a second end for engaging the first locking means (211a) of the shank portion at the rear end of the drill body. A drill characterized by having a locking means (209e).

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