A spiral drill bit

Abstract

Provided is a spiral drill bit mounted on a spiral head, which has high excavation efficiency. The present invention is a spiral drill bit 11 mounted on a spiral head, comprising a base portion with a front end protruding in the axial direction of the spiral head and two foot portions 13, 14 which are continuous with the base portion and extend from the base portion and face each other at a predetermined interval; the base portion is composed of a plane portion 12a which is parallel to and continuous with the plane of the foot portion, first inclined portions 12b to 12d which are inclined from the plane portion to the front end side along the axial direction of the spiral head, first side portions 12e, 12f which are continuous from the first inclined portion, and a second inclined portion 12g which is inclined from the first inclined portion to the foot portion along the axial direction of the spiral head, and the plane portion and the foot portion are curved with a predetermined curvature relative to the axial direction of the spiral head.

Description

Technical Field

[0001] The invention relates to a spiral drill bit for a spiral head. Background Art

[0002] Conventionally, for example, in a precast pile construction method using a pile driver, an auger head is connected to a driving mechanism to dig a foundation hole for a building, a construction hole for a continuous underground wall, etc., and a blade for digging is provided on the auger head at the top of the auger head. This is roughly the same as the steel pipe hole construction method.

[0003] Among them, for example, in patent document 1, in a detachable earth drilling bit composed of a drill body, a drill holder and a connecting member, the drill body is composed of an excavating head and a shank connected thereto, the excavating head has an excavating blade made of cemented carbide, the shank is provided with an intermediate contraction portion and a circular portion, so that the shank is formed into a cross-section approximately in the shape of an 8, and a half-missing stopping recess is formed in the approximately middle portion of the longitudinal direction, the end surface of the drill holder is penetrated by a receiving hole for inserting the shank, the upper and lower surfaces of the drill holder are penetrated by mounting holes, which intersect with the receiving hole and are completed by the stopping recess of the shank, and when inserted into the mounting hole of the drill holder, the middle part of the connecting member is located in the stopping recess of the shank.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent document 1: Japanese Patent Publication No. 2002-339680. Summary of the invention

[0007] Problem to be solved by the invention

[0008] However, in Patent Document 1, only a detachable earth drill bit and an earth drill having an improved detachable structure are disclosed.

[0009] Furthermore, in conventional spiral drill bits for spiral heads, there is no technology for improving the excavation efficiency by making the spiral drill bit tapered and bent in an R-shape with a predetermined curvature, or by widening the drill bit width to eliminate defects and improve wear resistance, thereby improving the excavation efficiency while ensuring the excavation diameter, and further improving the excavation efficiency by preventing interference with the guide device through the R-shape.

[0010] In view of the above problems, an object of the present invention is to provide an auger drill bit for an auger head that improves excavation efficiency.

[0011] Means of solving the problem

[0012] In order to solve the above-mentioned problems, a spiral drill bit according to a first embodiment of the present invention is a spiral drill bit installed on a spiral head, comprising a base portion whose front end protrudes in the axial direction of the spiral head, and two foot portions which are continuous with the base portion and extend from the base portion and are opposite to each other at a predetermined interval; the base portion is composed of a plane portion which is parallel to and continuous with the plane of the foot portion, a first inclined portion which is inclined from the plane portion toward the front end side along the axial direction of the spiral head, a second inclined portion and a third inclined portion which are continuous from the first inclined portion, a first side portion which is continuous from the second inclined portion, a second side portion which is continuous from the third inclined portion, and a first side portion which is continuous from the first to the third inclined portions along the The spiral head is composed of a fourth inclined portion which is inclined toward the foot in the axial direction; a super-hard alloy tip covering the first side portion and a part of the fourth inclined portion is provided at the lower end portion of the second inclined portion which is continuous with the first side portion and the fourth inclined portion, a super-hard alloy tip covering a part of the fourth inclined portion is provided at the lower central portion of the second inclined portion, a super-hard alloy tip covering the first to third inclined portions, the second side portion and the fourth inclined portion is provided at the lower end portion where the first to third inclined portions, the second side portion and the fourth inclined portion are continuous, and the planar portion and the foot are bent with a predetermined curvature relative to the axial direction of the spiral head.

[0013] According to the auger bit of the second embodiment of the present invention, in the first embodiment, the leg portion side of the base portion has a wide shape of 85 mm to 105 mm in the width direction of the flat portion of the auger bit.

[0014] In addition, according to the third embodiment of the present invention, the spiral drill bit is a spiral drill bit installed on a spiral head, including a base portion whose front end protrudes in the axial direction of the spiral head, and two legs that are continuous with and extend from the base and are opposite to each other at a predetermined interval, the base portion is composed of a plane portion continuous with the plane of the leg portion, a first inclined portion inclined from the plane portion toward the front end side along the axial direction of the spiral head, a side portion continuous from the first inclined portion, and a second inclined portion inclined from the first inclined portion toward the foot side along the axial direction of the spiral head; the plane portion of the base is tapered, and the length of the side where the plane portion is continuous with the foot on the front end side becomes smaller than the side where the plane portion is continuous with the foot on the foot side, and its width gradually decreases toward the front end side; the plane portion and the foot are curved with a predetermined curvature relative to the axial direction of the spiral head.

[0015] Effects of the Invention

[0016] According to the present invention, an auger bit for a casing auger which improves the excavation efficiency can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a side view of the spiral drill bit according to the first embodiment of the present invention.

[0018] Figure 2 1 is a structural diagram of a spiral drill bit according to a first embodiment of the present invention.

[0019] Figure 3 It is a side view of the spiral drill bit according to the second embodiment of the present invention.

[0020] Figure 4 It is a structural diagram of a spiral drill bit according to the second embodiment of the present invention.

[0021] Figure 5 It is a side view of a spiral drill bit according to a third embodiment of the present invention.

[0022] Figure 6 2 is a structural diagram of a spiral drill bit according to the third embodiment of the present invention.

[0023] Figure 7 It is a side view of a spiral drill bit according to a fourth embodiment of the present invention.

[0024] Figure 8 It is a structural diagram of a spiral drill bit according to the fourth embodiment of the present invention.

[0025] Fig. 9 It is a side view of a spiral drill bit according to a fifth embodiment of the present invention.

[0026] Fig.10 It is a structural diagram of a spiral drill bit according to the fifth embodiment of the present invention.

[0027] Fig.11 It is a side view of a spiral drill bit according to a sixth embodiment of the present invention.

[0028] Fig.12 It is a structural diagram of a spiral drill bit according to the sixth embodiment of the present invention.

[0029] Fig.13 Shown is the auger bit when mounted on the auger head.

[0030] Explanation of symbols

[0031] 1···Auger drill head, 2···base, 2a···plane, 2b, 2c, 2d···inclined portion, 2e, 2f···side portion, 2g···inclined portion, 3···leg, 3a···hole, 4···leg, 4a···hole, 5a, 5b, 5c···hard alloy tip, 6···hard thickened layer, 11···Auger drill head, 12···base, 12a···plane, 12b, 12c, 12d···inclined portion, 12e, 12f···side portion, 12g···inclined portion, 13·· · Foot, 13a···Hole, 14···Foot, 14a···Hole, 15a, 15b, 15c···Ultra-hard alloy tip, 16···Hard thickening layer, 21···Spiral drill, 22···Base, 22a···Flat surface, 22b, 22c, 22d···Inclined portion, 22e, 22f···Side surface, 22g···Inclined portion, 23···Foot, 23a···Hole, 24···Foot, 24a···Hole, 25···Ultra-hard alloy tip, 26···Hard thickening layer, 31·· ·Auger drill head, 32···base, 32a···plane, 32b, 32c, 32d···inclined portion, 32e, 32f···side portion, 32g···inclined portion, 33···foot, 33a···hole, 34···foot, 34a···hole, 35a, 35b, 35c···hard alloy tip, 36···hard thickened layer, 41···auger drill head, 42···base, 42a···plane, 42b, 42c, 42d···inclined portion, 42e, 42f···side portion, 4 2g···inclined portion, 43···foot, 43a···hole portion, 44···foot, 44a···hole portion, 45···superhard alloy tip, 46···hard thickened layer, 51···spiral drill bit, 52···base, 52a···plane portion, 52b, 52c, 52d···inclined portion, 52e, 52f···side portion, 52g···inclined portion, 53···foot, 53a···hole portion, 54···foot, 54a···hole portion, 55···superhard alloy tip, 56···hard thickened layer. DETAILED DESCRIPTION

[0032] Hereinafter, the construction and operation of an auger drill bit for a casing auger according to first to sixth embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0033] Figure 1 , 2 2(a) and 2(b) show and explain the structure of the spiral drill bit according to the first embodiment of the present invention. More specifically, Figure 1 is a side view of the same auger bit, Figure 2(a) is a plan view of the same spiral drill bit. Figure 2 (b) is a side view of the same auger bit.

[0034] As shown in these figures, the auger bit 1 is composed of a base 2 and two legs 3 and 4 extending from the base 2. In the first embodiment, the base 2 side is also referred to as the front end of the auger bit 1, and the legs 3 and 4 sides are also referred to as the mounting side of the auger head or the rear end of the auger bit 1.

[0035] The base 2 has a so-called mountain shape, and its top protrudes toward the front end side of the auger bit 1 along the axial direction of the screw head. More specifically, the flat surface 2a of the base 2 of the auger bit 1 is parallel to the planes of the legs 3 and 4, and three inclined portions 2b, 2c and 2d are continuous from the flat surface 2a along the axial direction of the screw head toward the front end side.

[0036] In this example, when viewed from the front end side in the axial direction of the spiral head, the left end of the inclined portion 2b is continuous with the side portion 2e, and when viewed from the left end side in the axial direction of the spiral head, the right end of the inclined portion 2d is continuous with the side portion 2f.

[0037] When viewed from the front end side in the axial direction of the spiral head, the inclined portions 2b, 2c and 2d of the base portion 2 are sequentially connected in the transverse direction, that is, the circumferential direction of the spiral head. In this embodiment, the inclined portion 2b is inclined in the circumferential direction of the spiral head relative to the inclined portion 2c, and the inclined portion 2d is inclined in the circumferential direction of the spiral head of the inclined portion 2b (in the direction opposite to the inclination direction of the inclined portion 2c) relative to the inclined portion 2c.

[0038] The lower ends of the inclined portions 2b, 2c and 2d of the base 2 are all continuous with the inclined portion 2g. The inclined portion 2g is 15 degrees relative to the plane parallel to the plane portion 2a, and is inclined toward the rear end side in the axial direction of the spiral head, that is, the installation side of the spiral drill bit 1 on the spiral head. In this embodiment, a hard thickening layer 6 is provided on the base 2.

[0039] The legs 3 and 4 extend in a U shape from the base 2 to the rear end at predetermined intervals along the axial direction of the screw head. The legs 3 and 4 are provided with four holes 3a and 4a respectively for mounting the auger bit 1 on the screw head with bolts or the like.

[0040] Superhard alloy tips 5a, 5b, 5c are provided on the inclined portions 2b, 2c, 2d of the base 2 of the spiral drill bit 1. More specifically, in the lower end portion continuous with the side portion 2e and the inclined portion 2g of the inclined portion 2b, a superhard alloy tip 5a covering the side portion 2e and a part of the inclined portion 2g is provided. In the lower end portion continuous with the inclined portions 2b, 2c, 2d, a superhard alloy tip 5b covering the inclined portions 2b, 2c, 2d and a part of the inclined portion 2g is provided. Furthermore, in the lower end portion continuous with the side portion 2f and the inclined portion 2g of the inclined portion 2d, a superhard alloy tip 5c covering the side portion 2f and a part of the inclined portion 2g is provided.

[0041] By using these super-hard alloy tips 5a to 5c, wear of the outer side of the contact surface can be prevented. In addition, the material and hardness of the plurality of super-hard alloy tips can be freely combined appropriately according to the foundation or obstacle to be excavated. For example, in the auger bit 1 according to the first embodiment, super-hard alloy tips of up to 5 materials can be arbitrarily selected and used in combination, effectively preventing defects caused by excavation of a wide range of excavation objects during excavation.

[0042] The base 2 of the spiral drill bit 1 is bilaterally symmetrical in the axial direction of the spiral head, with the line passing through the center of the flat portion 2a as the symmetry axis. Thus, while the shape is bilaterally symmetrical, the protection performance is enhanced by setting an inclination angle on each surface of the inclined portions 2b, 2c, 2d, and 2g, and setting superhard alloy tips at predetermined intervals as described above.

[0043] Regarding the material, the feet 3 and 4 can use SCM440 (chrome steel) as the base material, and the super-hard alloy tips 5a to 5c can use E3 (material name MG30), E4 (material name MG40), E5 (material name MG50), E6 (material name MG60) and the like in the JIS usage classification symbols or G4 (CIS material symbol VC-40), G5 (CIS material symbol VC-50) and the like in the CIS standard.

[0044] As described above, according to the first embodiment of the present invention, since the cemented carbide tip is divided into three parts, the damage and wear of the blade of the spiral drill bit can be reduced, and the excavation efficiency can be improved. In addition, compared with the cemented carbide tip being one piece, the entire cemented carbide tip will not be unusable due to one defect, so the replacement rate of the spiral drill bit can be reduced.

[0045] <Second Embodiment>

[0046] Figure 3 , 4 4(a) and 4(b) show and explain the structure of the spiral drill bit according to the second embodiment of the present invention. More specifically, Figure 3 is a side view of the same auger bit, Figure 4(a) is a plan view of the same spiral drill bit. Figure 4 (b) is a side view of the same auger bit.

[0047] As shown in these figures, the auger bit 11 is composed of a base 12 and two legs 13, 14 extending from the base 12. In the second embodiment, the base 12 side is also referred to as the front end of the auger bit 11, and the legs 13, 14 side is also referred to as the mounting side of the auger head or the rear end of the auger bit 11.

[0048] The base 12 has a so-called mountain shape, and its top protrudes toward the front end side of the auger bit 11 along the axial direction of the auger head. More specifically, the flat surface 12a of the base 12 of the auger bit 11 is parallel to the planes of the legs 13 and 14, and three inclined portions 12b, 12c and 12d are continuous from the flat surface 12a along the axial direction of the auger head toward the front end side.

[0049] In this example, when viewed from the front end side in the axial direction of the helical head, the left end of the inclined portion 12b is continuous with the side portion 12e, and when viewed from the left end side in the axial direction of the helical head, the right end of the inclined portion 12d is continuous with the side portion 12f.

[0050] When viewed from the front end side in the axial direction of the spiral head, the inclined portions 12b, 12c and 12d of the base portion 12 are sequentially connected in the transverse direction, that is, the circumferential direction of the spiral head. In this embodiment, the inclined portion 12b is inclined in the circumferential direction of the spiral head relative to the inclined portion 12c, and the inclined portion 12d is inclined in the circumferential direction of the spiral head of the inclined portion 12b (in the direction opposite to the inclination direction of the inclined portion 12b) relative to the inclined portion 12c.

[0051] The lower ends of the inclined portions 12b, 12c and 12d of the base 12 are all continuous with the inclined portion 12g. The inclined portion 12g is inclined at 15 degrees relative to a plane parallel to the plane portion 12a, and is inclined toward the rear end side in the axial direction of the screw head, that is, the side where the screw drill bit 11 is installed on the screw head. In addition, in this embodiment, a hard thickening layer 16 is provided on the base 12.

[0052] The legs 13 and 14 extend in a U shape from the base 12 to the rear end at predetermined intervals along the axial direction of the screw head. The legs 13 and 14 are provided with four holes 13a and 14a for mounting the auger bit 11 on the screw head with bolts or the like.

[0053] A super-hard alloy tip 15 is provided at the lower part of the inclined parts 12b, 12c, and 12d of the base 12 of the auger 11. The super-hard alloy tip 15 can prevent the wear of the outer side of the contact surface. In addition, the material and hardness of the super-hard alloy tip can be freely combined appropriately according to the foundation or obstacle to be excavated.

[0054] Regarding the materials of each part, the feet 13 and 14 can use SCM440 (chrome steel) as the base material, and the superhard alloy tip 15 can use E3 (material name MG30), E4 (material name MG40), E5 (material name MG50), E6 (material name MG60) and other JIS usage classification symbols or G4 (CIS material symbol VC-40), G5 (CIS material symbol VC-50) and other CIS standards.

[0055] The flat portion 12a of the base 12 of the auger bit 11, the foot portions 13, 14 have an R shape that is curved with a predetermined curvature matching the diameter of the auger head relative to the axial direction of the auger head. In this embodiment, the front end of the blade is designed to be located on a circumference of φ850 mm, and the curvature of the R shape is R500 (inner circumference R395 (wide R shape)). With such a configuration, by using the auger head with a dedicated bracket, the excavation efficiency of the outer periphery of the auger head can be improved.

[0056] As described above, according to the second embodiment of the present invention, the plane portion and the like have an R-shape bent at a predetermined curvature according to the diameter of the auger bit, thereby preventing interference with the guide sleeve and reducing damage when the blade collides with the guide sleeve. In addition, due to the R-shape, the blade position is closer to the outside than the middle position, so that it is possible to perform excavation further to the outside than the blade in the middle position, not only ensuring the excavation diameter, but also increasing the size. In addition, due to the R-shape, the load during excavation can be reduced, and the excavation efficiency can be improved.

[0057] <Third Embodiment>

[0058] Figure 5 , 6 6(a) and 6(b) show and explain the structure of the spiral drill bit according to the third embodiment of the present invention. More specifically, Figure 5 is a side view of the same auger bit, Figure 6 (a) is a side view of the same spiral drill bit. Figure 4 (b) is a bottom view of the same spiral drill bit.

[0059] As shown in these figures, the auger bit 21 is composed of a base 22 and two legs 23, 24 extending from the base 22. In the third embodiment, the base 22 side is also referred to as the front end of the auger bit 21, and the legs 23, 24 side is also referred to as the mounting side of the auger head or the rear end of the auger bit 21.

[0060] The base 22 has a so-called mountain shape, and its top protrudes toward the front end side of the auger bit 21 along the axial direction of the auger head. More specifically, the plane portion 22a of the base 22 of the auger bit 21 is parallel to the planes of the legs 23 and 24, and three inclined portions 22b, 22c and 22d are continuous from the plane portion 22a along the axial direction of the auger head toward the front end side.

[0061] In this example, when viewed from the front end side in the axial direction of the helical head, the left end of the inclined portion 22b is continuous with the side portion 22e, and when viewed from the left end side in the axial direction of the helical head, the right end of the inclined portion 22d is continuous with the side portion 22f.

[0062] When viewed from the front end side in the axial direction of the spiral head, the inclined portions 22b, 22c and 22d of the base portion 22 are sequentially connected in the transverse direction, that is, the circumferential direction of the spiral head. In this embodiment, the inclined portion 22b is inclined in the circumferential direction of the spiral head relative to the inclined portion 22c, and the inclined portion 22d is inclined in the circumferential direction of the spiral head of the inclined portion 22b (in the direction opposite to the inclination direction of the inclined portion 22b) relative to the inclined portion 22c.

[0063] The lower ends of the inclined portions 22b, 22c and 22d of the base 22 are all continuous with the inclined portion 22g. The inclined portion 22g is 15 degrees relative to the plane parallel to the plane portion 22a, and is inclined toward the rear end side in the axial direction of the screw head, that is, the side where the screw drill bit 21 is installed on the screw head. In addition, in this embodiment, a hard thickening layer 26 is provided on the base 22.

[0064] The legs 23 and 24 extend in a U-shape from the base 22 to the rear end at predetermined intervals along the axial direction of the screw head. The legs 23 and 24 are provided with four holes 23a and 24a for mounting the screw drill bit 21 on the screw head with bolts or the like.

[0065] A super-hard alloy tip 25 is provided at the lower part of the inclined parts 22b, 22c, and 22d of the base 22 of the auger 21. The wear of the outer side of the contact surface can be prevented by the super-hard alloy tip 25. In addition, the material and hardness of the multiple super-hard alloy tips can be freely combined as appropriate according to the foundation or obstacle to be excavated.

[0066] Regarding the materials of each part, the feet 23 and 24 can use SCM440 (chrome steel) as the base material, and the superhard alloy tip 25 can use E3 (material name MG30), E4 (material name MG40), E5 (material name MG50), E6 (material name MG60) and other materials in the JIS usage classification symbols or G4 (CIS material symbol VC-40), G5 (CIS material symbol VC-50) and other materials in the CIS standard.

[0067] The flat surface 22a of the base 22 of the auger 21 and the legs 23 and 24 have wider blades than those of ordinary auger bits. That is, the width of the flat surface 22a in a direction perpendicular to the axial direction of the auger, i.e., the width along the circumferential direction of the auger, is wider than that of ordinary auger bits.

[0068] More specifically, the width of the flat portion 22a in the direction perpendicular to the axial direction of the spiral head is wider than that of a common spiral drill bit. For example, the blade width of a spiral drill bit for a common casing spiral drill is 60 mm on a 60 mm wide bracket and 80 mm on an 80 mm wide bracket, but in this embodiment, the blade width of the spiral drill bit is 85 mm on a 60 mm wide bracket and 105 mm on an 80 mm wide bracket. Since the spiral drill bit itself has a wide shape, the already installed bracket can be used as it is.

[0069] In the past, the only way to increase the width of the auger bit was to increase the size of the bracket or weld a 20-25 mm wide auger bit for the auger, but as described above, it can be used by simply attaching it to the existing bracket.

[0070] As described above, according to the third embodiment of the present invention, the wide shape can suppress the damage and wear of the auger bit. In addition, the existing auger bit holder can be used directly and installed.

[0071] <Fourth Embodiment>

[0072] Figure 7 , 8 8(a) and 8(b) show and explain the structure of the spiral drill bit according to the fourth embodiment of the present invention. More specifically, Figure 7 is a side view of the same auger bit, Figure 8 (a) is a plan view of the same spiral drill bit. Figure 8 (b) is a side view of the same auger bit.

[0073] As shown in these figures, the auger bit 31 is composed of a base 32 and two legs 33, 34 extending from the base 32. In the fourth embodiment, the base 32 side is also referred to as the front end of the auger bit 31, and the legs 33, 34 side is also referred to as the mounting side of the auger head or the rear end of the auger bit 31.

[0074] The base 32 has a so-called mountain shape, and its top protrudes toward the front end side of the auger bit 31 along the axial direction of the auger head. More specifically, the plane portion 32a of the base 32 of the auger bit 31 is parallel to the planes of the legs 33 and 34, and three inclined portions 32b, 32c and 32d are continuous from the plane portion 32a along the axial direction of the auger head toward the front end side.

[0075] In this example, when viewed from the front end side in the axial direction of the spiral head, the left end of the inclined portion 32b is continuous with the side portion 32e, and when viewed from the left end side in the axial direction of the spiral head, the right end of the inclined portion 32d is continuous with the side portion 32f.

[0076] When viewed from the front end side in the axial direction of the spiral head, the inclined portions 32b, 32c and 32d of the base portion 32 are sequentially connected in the transverse direction, that is, the circumferential direction of the spiral head. In this embodiment, the inclined portion 32b is inclined in the circumferential direction of the spiral head relative to the inclined portion 32c, and the inclined portion 32d is inclined in the circumferential direction of the spiral head of the inclined portion 32b (in the direction opposite to the inclination direction of the inclined portion 32b) relative to the inclined portion 32c.

[0077] The lower ends of the inclined portions 32b, 32c and 32d of the base 32 are all continuous with the inclined portion 32g. The inclined portion 32g is 15 degrees relative to the plane parallel to the plane portion 32a, and is inclined toward the rear end side in the axial direction of the screw head, that is, the side where the screw drill bit 31 is installed on the screw head. In addition, in this embodiment, a hard thickening layer 36 is provided on the base 32.

[0078] The legs 33 and 34 extend in a U-shape from the base 32 toward the rear end at predetermined intervals along the axial direction of the screw head. The legs 33 and 34 are provided with four holes 33a and 34a for mounting the auger bit 31 on the screw head with bolts or the like.

[0079] Superhard alloy tips 35a, 35b, 35c are provided on the inclined parts 32b, 32c, 32d of the base 32 of the spiral drill bit 31. More specifically, a superhard alloy tip 35a covering a part of the side part 32e and the inclined part 32g is provided at the lower end where the side part 32e and the inclined part 32g of the inclined part 32b are continuous. A superhard alloy tip 35b covering a part of the inclined part 32g is provided at the approximately central part below the inclined part 2b. A superhard alloy tip 35c covering these inclined parts 32b, 32c, 32d, the side part 32f, and the inclined part 32g is provided at the lower end where the inclined parts 32b, 32c, 32d, the side part 32f, and the inclined part 32g are continuous.

[0080] By using these super-hard alloy tips 35a to 35c, wear of the outer side of the contact surface can be prevented. In addition, the material and hardness of the plurality of super-hard alloy tips can be freely combined appropriately according to the foundation or obstacle to be excavated. For example, in the auger bit 31 according to the present embodiment, super-hard alloy tips of up to 5 materials can be selected and used in combination, effectively preventing defects etc. generated during excavation of a wide range of excavation objects.

[0081] Regarding the materials of each part, the feet 33 and 34 can use SCM440 (chrome steel) as the base material, and the superhard alloy tips 35a to 35c can use E3 (material name MG30), E4 (material name MG40), E5 (material name MG50), E6 (material name MG60) and other materials in the JIS usage classification symbols or G4 (CIS material symbol VC-40), G5 (CIS material symbol VC-50) and other materials in the CIS standard.

[0082] The flat surface portion 32a of the base 32 of the auger bit 31 and the foot portions 33 and 34 have an R shape that is curved with a predetermined curvature matching the diameter of the auger head relative to the axial direction of the auger head. In this embodiment, the front end of the blade is designed to be located on a circumference of φ850 mm, and the curvature of the R shape is R475. With such a configuration, by using the auger head with a dedicated bracket, the excavation efficiency of the outer periphery of the auger head can be improved.

[0083] In addition, the flat surface 32a of the base 32 of the auger bit 31 and the legs 33 and 34 have wider blades than those of ordinary auger bits. That is, the width of the flat surface 32a in a direction perpendicular to the axial direction of the auger bit, i.e., the width along the circumferential direction of the auger bit, is wider than that of ordinary auger bits.

[0084] More specifically, the width of the flat surface portion 32a in the direction perpendicular to the axial direction of the screw head is wider than that of a general screw drill bit.

[0085] For example, the blade width of a general spiral drill bit for an ordinary casing spiral drill is 60 mm on a 60 mm wide bracket and 80 mm on an 80 mm wide bracket. However, in the spiral drill bit according to the fourth embodiment, the blade width is 85 mm on a 60 mm wide bracket and 105 mm on an 80 mm wide bracket. Since the spiral drill bit itself has a wider shape, the already installed bracket can be used as is.

[0086] As described above, according to the fourth embodiment of the present invention, since the cemented carbide tip is divided into three parts, the damage and wear of the blade of the spiral drill bit can be reduced, and the excavation efficiency can be improved. In addition, compared with the cemented carbide tip being one piece, the entire cemented carbide tip will not be unusable due to one defect, so the replacement rate of the spiral drill bit can be reduced.

[0087] Furthermore, according to the fourth embodiment of the present invention, since the flat surface of the base has an R shape, interference with the guide sleeve can be prevented, and damage when the blade collides with the guide sleeve can be reduced. The blade position is closer to the outside than the middle position, so that digging can be performed further to the outside compared to the blade in the middle position, not only ensuring the digging diameter, but also increasing the size. In addition, since the shape is an R shape with a curvature that matches the diameter of the auger bit, the load during digging can be reduced, and the digging efficiency can be improved.

[0088] According to the fourth embodiment of the present invention, the wide shape can suppress the damage and wear of the auger bit. In addition, the existing auger bit holder can be used as it is and installed.

[0089] <Fifth Embodiment>

[0090] Fig. 9 , 1010(a) and 10(b) show and explain the structure of the spiral drill bit according to the fifth embodiment of the present invention. More specifically, Fig. 9 is a side view of the same auger bit, Fig.10 (a) is a plan view of the same spiral drill bit. Fig.10 (b) is a side view of the same auger bit.

[0091] As shown in these figures, the auger bit 41 is composed of a base 42 and two legs 43, 44 extending from the base 42. In the fifth embodiment, the base 42 side is also referred to as the front end of the auger bit 41, and the legs 43, 44 side is also referred to as the mounting side of the auger head or the rear end of the auger bit 41.

[0092] The base 42 has a so-called mountain shape, and its top protrudes along the axial direction of the screw head toward the front end side of the screw drill bit 41. More specifically, the flat surface 42a of the base 42 of the screw drill bit 41 is inclined downward by 15 degrees toward the front end side of the screw head relative to the plane of the foot portions 43 and 44, and three inclined portions 42b, 42c and 42d are continuous from the flat surface 42a and further inclined toward the front end side along the axial direction of the screw head.

[0093] In this example, when viewed from the front end side in the axial direction of the spiral head, the left end of the inclined portion 42b is continuous with the side portion 42e, and when viewed from the left end side in the axial direction of the spiral head, the right end of the inclined portion 42d is continuous with the side portion 42f.

[0094] When viewed from the front end side in the axial direction of the spiral head, the inclined portions 42b, 42c and 42d of the base portion 42 are sequentially connected in the transverse direction, that is, the circumferential direction of the spiral head. In this embodiment, the inclined portion 42b is inclined in the circumferential direction of the spiral head relative to the inclined portion 42c, and the inclined portion 42d is inclined in the circumferential direction of the spiral head of the inclined portion 42b (in the direction opposite to the inclination direction of the inclined portion 42b) relative to the inclined portion 42c.

[0095] The lower ends of the inclined portions 42b, 42c and 42d of the base 42 are all continuous with the inclined portion 42g. The inclined portion 42g is 15 degrees relative to the plane parallel to the plane portion 42a, and is inclined toward the rear end side in the axial direction of the screw head, that is, the side where the screw drill bit 41 is installed on the screw head. In addition, in this embodiment, a hard thickening layer 46 is provided on the base 42.

[0096] The legs 43 and 44 extend in a U-shape from the base 42 to the rear end at predetermined intervals along the axial direction of the screw head. The legs 43 and 44 are provided with four holes 43a and 44a for mounting the screw bit 41 on the screw head with bolts or the like.

[0097] A superhard alloy tip 45 is provided on the inclined portions 42b, 42c, 42d of the base 42 of the auger 41. The superhard alloy tip 45 can prevent wear of the outer side of the contact surface. In addition, the material quality and hardness of the superhard alloy can be freely selected according to the foundation or obstacle of the excavation object.

[0098] Regarding the materials of each part, the feet 43 and 44 can use SCM440 (chrome steel) as the base material, and the superhard alloy tip 45 can use E3 (material name MG30), E4 (material name MG40), E5 (material name MG50), E6 (material name MG60) and the like in the JIS usage classification symbols or G4 (CIS material symbol VC-40), G5 (CIS material symbol VC-50) and the like in the CIS standard.

[0099] The base 42 of the auger bit 41 has a longer and thinner front end than that of a common auger bit, so it has good bite to the excavation object and high excavation efficiency.

[0100] In other words, more specifically, compared to a conventional spiral drill bit having a blade width of 60 mm on a 60 mm wide bracket and 80 mm on a 80 mm wide bracket, the blade width of the spiral drill bit 41 according to the fifth embodiment is 40 mm on a 60 mm wide bracket and 50 mm on a 80 mm wide bracket. In the illustrated example, the flat surface portion 42a of the base 42 is tapered, with a maximum width of 80 mm and a minimum width of 50 mm, and the width gradually decreases from 80 mm to 50 mm toward the front end.

[0101] In addition, compared with the conventional spiral drill bit whose blade is 60 mm wide and 185 mm long on a 60 mm wide bracket, and 80 mm wide and 215 mm long on an 80 mm wide bracket, the spiral drill bit 41 according to the fifth embodiment has a blade of 40 mm wide and 250 mm long on a 60 mm wide bracket, and a blade of 50 mm wide and 280 mm or 310 mm long on an 80 mm wide bracket.

[0102] The auger bit according to the fifth embodiment can be used in combination with an existing auger bit or can be used alone. That is, for example, on a 80 mm wide bracket with a blade width of 50 mm and a length of 280 mm / 310 mm, a common auger bit with a length of 280 mm or 310 mm and three auger bits according to this embodiment can be used in combination.

[0103] As described above, according to the fifth embodiment of the present invention, since the base of the auger bit is a thinner and longer cone, it has good bite properties on the excavation object and can improve the excavation efficiency.

[0104] <Sixth Embodiment>

[0105] Fig.11 , 12 12(a) and 12(b) show and explain the structure of the spiral drill bit according to the sixth embodiment of the present invention. More specifically, Fig.11 is a side view of the same auger bit, Fig.12 (a) is a plan view of the same spiral drill bit. Fig.12 (b) is a side view of the same auger bit.

[0106] As shown in these figures, the auger bit 51 is composed of a base 52 and two legs 53, 54 extending from the base 52. In the sixth embodiment, the base 52 side is also referred to as the front end of the auger bit 51, and the legs 53, 54 side is also referred to as the mounting side of the auger head or the rear end of the auger bit 51.

[0107] The base 52 has a so-called mountain shape, and its top protrudes along the axial direction of the screw head toward the front end side of the screw drill bit 51. More specifically, the flat surface 52a of the base 52 of the screw drill bit 51 is inclined downward by 15 degrees toward the front end side of the screw head relative to the plane of the foot portions 53 and 54, and three inclined portions 52b, 52c and 52d are continuous from the flat surface 52a and further inclined toward the front end side along the axial direction of the screw head.

[0108] In this example, when viewed from the front end side in the axial direction of the spiral head, the left end of the inclined portion 52b is continuous with the side portion 52e, and when viewed from the left end side in the axial direction of the spiral head, the right end of the inclined portion 52d is continuous with the side portion 52f.

[0109] When viewed from the front end side in the axial direction of the spiral head, the inclined portions 52b, 52c and 52d of the base portion 52 are sequentially connected in the transverse direction, that is, the circumferential direction of the spiral head. In this embodiment, the inclined portion 52b is inclined in the circumferential direction of the spiral head relative to the inclined portion 52c, and the inclined portion 52d is inclined in the circumferential direction of the spiral head of the inclined portion 52b (in the direction opposite to the inclination direction of the inclined portion 52b) relative to the inclined portion 52c.

[0110] The lower ends of the inclined portions 52b, 52c and 52d of the base 52 are all continuous with the inclined portion 52g. The inclined portion 52g is inclined at 15 degrees relative to a plane parallel to the plane portion 52a, and is inclined toward the rear end side in the axial direction of the screw head, that is, the side where the screw drill bit 51 is installed on the screw head. In addition, in this embodiment, a hard thickening layer 56 is provided on the base 52.

[0111] The legs 53 and 54 extend in a U-shape from the base 52 to the rear end at predetermined intervals along the axial direction of the screw head. The legs 53 and 54 are provided with four holes 53a and 54a for mounting the screw bit 51 on the screw head with bolts or the like.

[0112] A super-hard alloy tip 55 is provided at the lower part of the inclined parts 52b, 52c, 52d of the base 52 of the auger 51. The super-hard alloy tip 55 can prevent the wear of the outer side of the contact surface. In addition, the material quality and hardness of the super-hard alloy can be freely selected according to the foundation or obstacle of the excavation object.

[0113] Regarding the materials of each part, the feet 53 and 54 can use SCM440 (chrome steel) as the base material, and the superhard alloy tip 45 can use E3 (material name MG30), E4 (material name MG40), E5 (material name MG50), E6 (material name MG60) and the like in the JIS usage classification symbols or G4 (CIS material symbol VC-40), G5 (CIS material symbol VC-50) and the like in the CIS standard.

[0114] The base 52 of the auger bit 51 has a longer and thinner front end than that of a common auger bit, so it has good bite to the excavation object and high excavation efficiency.

[0115] More specifically, compared to a conventional spiral drill bit having a blade width of 60 mm on a 60 mm wide bracket and 80 mm on an 80 mm wide bracket, the blade width of the spiral drill bit 51 according to the present embodiment is 40 mm on a 60 mm wide bracket and 50 mm on an 80 mm wide bracket. In the illustrated example, the plane portion 52a of the base 52 is tapered, with a maximum width of 80 mm and a minimum width of 50 mm, and the width gradually decreases from 80 mm to 50 mm toward the front end.

[0116] In addition, compared with the ordinary spiral drill bit whose blade width is 60mm and length is 185mm on a 60mm wide bracket, and whose width is 80mm and length is 215mm on an 80mm wide bracket, according to the spiral drill bit 51 of the sixth embodiment, the blade width is 40mm and length is 250mm on a 60mm wide bracket, and whose width is 50mm and length is 280mm or 310mm on an 80mm wide bracket.

[0117] The auger bit according to this embodiment can be used in combination with an existing auger bit or can be used alone. For example, on a 80 mm wide support having a blade width of 50 mm and a length of 280 mm / 310 mm, a common auger bit of 280 mm or 310 mm and three auger bits according to the sixth embodiment can be used in combination.

[0118] The flat surface portion 52a, the foot portions 53, 54 of the base portion 52 of the auger bit 51 have an R shape that is curved with a predetermined curvature matching the diameter of the auger head relative to the axial direction of the auger head. In this embodiment, the front end of the blade is designed to be located on a circumference of φ850 mm, the curvature of the R shape is R475, and the inner circumference is R395. With such a configuration, by using the auger head with a dedicated bracket, the excavation efficiency of the outer circumference of the auger head can be improved.

[0119] As described above, according to the sixth embodiment of the present invention, since the base of the auger bit is in a tapered R shape, it has good engagement with the excavation object and can improve the excavation efficiency.

[0120] In addition, since the flat surface of the base is in an R shape, interference with the guide sleeve can be prevented, and damage when the blade collides with the guide sleeve can be reduced. In addition, the blade position is closer to the outside than the middle position, so the excavation diameter can be increased. In addition, since it is bent into an R shape with a predetermined curvature that matches the diameter of the auger bit, the load during excavation can be reduced, and the excavation efficiency can be improved.

[0121] Finally, according to Fig.13 , the fourth embodiment and the sixth embodiment illustrate how the spiral drill bit is installed on the spiral head. More specifically, Fig.13 (a) shows the side view of the installation, Fig.13 (b) shows a front view.

[0122] As shown in these figures, the screw head 100 has a so-called screw shape, and one of the front ends of the two branches has a screw drill bit 101 according to the fourth embodiment, and screw drill bits 102 and 103 according to the sixth embodiment, and the screw drill bits 101, 102, and 103 are installed in parallel from the outside to the center. On the other side of the front end, there are a screw drill bit 104 according to the fourth embodiment and a screw drill bit 105 according to the sixth embodiment, and the screw drill bits 104 and 105 are installed in parallel from the outside to the center. In this way, the screw drill bits 101 and 104 according to the fourth embodiment are provided on the outermost side, and their R shape is similar to the R of the screw head 100, so that smooth rotation and excavation are achieved. At the same time, since the screw drill bits 101 and 104 have a wide shape, they are highly resistant to damage caused by wear and the like. And the screw drill bits 102, 103, and 105 according to the sixth embodiment are arranged toward the center, and since they have a tapered longitudinal shape, they can perform good excavation regardless of the type of excavation object.

[0123] Although the first to sixth embodiments of the present invention have been described above, the present invention is not limited thereto, and it goes without saying that various improvements and changes can be made without departing from the gist of the present invention.

[0124] For example, the auger drill bit for casing auger according to this embodiment can be used in constructions using, for example, precast pile construction method or steel pipe middle hole construction method, and when performing these constructions, the chipping, slipping and wear of the superhard alloy tip are reduced compared to the past.

Claims

1. A spiral drill bit, the spiral drill bit is a spiral drill bit installed on a spiral head, comprising: A base, the front end of which protrudes toward the axial direction of the spiral head; as well as 2 feet, the feet being continuous with the base and extending from the base and facing each other at a predetermined interval; Wherein, the base comprises: A plane portion parallel to the planes of the two foot portions; a first inclined portion which is continuous with the planar portion and inclined toward the front end along the axial direction of the spiral head; a second inclined portion continuous with the planar portion and the first side of the first inclined portion and inclined toward the front end along the axial direction of the helical head; a third inclined portion continuous with the planar portion and the second side of the first inclined portion and inclined toward the front end along the axial direction of the spiral head; A first side surface portion continuous from the second inclined portion; A second side surface portion continuous from the third inclined portion; and a fourth inclined portion inclined from the first inclined portion, the second inclined portion, and the third inclined portion toward the two legs along the axial direction of the spiral head; A first cemented carbide tip is provided at a lower end portion of the second inclined portion which is continuous with the first side portion and the fourth inclined portion and covers a portion of the first side portion and a portion of the fourth inclined portion; A second cemented carbide tip is provided at a lower central portion of the second inclined portion so as to cover a portion of the fourth inclined portion; and A third super-hard alloy tip covering the first inclined portion, the second inclined portion, the third inclined portion, the second side portion, and the fourth inclined portion is provided at a continuous lower end portion of the first inclined portion, the second inclined portion, the third inclined portion, the second side portion, and the fourth inclined portion; and The plane portion and the two legs have a shape that is curved with a predetermined curvature matching the diameter of the spiral head relative to the axial direction of the spiral head; wherein, when viewed from the front end in the axial direction of the spiral head, the second inclined portion, the first inclined portion and the third inclined portion are sequentially continuous in the transverse direction; The lower ends of the first inclined portion, the second inclined portion and the third inclined portion of the base are all continuous with the fourth inclined portion, and the fourth inclined portion is inclined toward the rear end side in the axial direction of the spiral head. 2 . The auger drill bit according to claim 1 , wherein the base portion has a relatively wide shape with a width of 85 mm to 105 mm on the two leg portions side in the width direction of the flat surface portion of the auger drill bit.

3. A spiral drill bit, the spiral drill bit is a spiral drill bit installed on a spiral head, comprising: 2 feet, facing each other at a predetermined interval; as well as A base, the base being connected to the front ends of the two legs along the axial direction of the spiral head; Wherein, the base comprises: A plane portion parallel to the planes of the two foot portions; A first inclined portion inclined from the flat portion along the axial direction of the spiral head toward the front end; a side surface portion continuous from the first inclined portion; a second inclined portion inclined from the first inclined portion along the axial direction of the spiral head toward the leg portion; A superhard alloy tip is provided at the lower part of the second inclined portion and the first inclined portion; The plane portion of the base is tapered, and the length of the side where the plane portion is continuous with the first inclined portion and the second inclined portion at the front end is smaller than the side where the plane portion is continuous with the foot at the foot side, and the width thereof gradually decreases toward the front end; The flat portion and the two leg portions have a shape that is curved with a predetermined curvature relative to the axial direction of the screw head, and the curvature matches the diameter of the screw head.

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