Drill bit with replaceable bit

Abstract

The invention relates to the technical field of drill bits, in particular to a drill bit with a replaceable bit, which comprises a drill tip and a drill handle, the drill tip and the drill handle can be separated, and the drill tip is connected with the drill handle through an internal thread and a positioning surface of a drill tip connecting part; the drill tip consists of two parts, namely a working part and a connecting part; the connecting part consists of three parts, namely a positioning side surface, a bottom plane and a connecting thread; the working part consists of a circumferential edge, a main cutting edge, a chisel edge, a rear cutter surface and a spiral groove A; the circumferential blade is composed of a shovel back face and a blade strip. According to the replaceable-head drill bit, a powder pressing forming process is used, so that a blank is approximately formed, only a small amount of local grinding is needed, the machining time is greatly shortened, material removal is greatly reduced, and the production cost is remarkably reduced.

Description

Technical Field

[0001] The invention relates to the technical field of drill bits, in particular to a drill bit with a replaceable head. Background Art

[0002] In drilling processing, solid carbide drills are widely used. Compared with high-speed steel drills, solid carbide drills have greater advantages in service life, processing quality, and processing stability. However, the cost of solid carbide drills is very high. From the bar raw material to the final product, a large amount of material needs to be removed by grinding. This process consumes a lot of man-hours, energy, and raw materials. This is the main reason for the high cost of solid carbide drills. For this reason, a replaceable head drill is provided. Summary of the invention

[0003] The purpose of the present invention is to provide a drill bit with a replaceable head to solve the problems raised by the above-mentioned background technology in view of the defects of the prior art.

[0004] To achieve the above object, the present invention provides the following technical solutions: a replaceable drill bit, comprising a drill tip and a drill shank, wherein the drill tip and the drill shank are separable and connected to the drill shank by using the internal thread and positioning surface of the drill tip connecting part; The drill tip is composed of two parts, namely a working part and a connecting part; the connecting part is composed of three parts, namely a positioning side surface, a bottom plane and a connecting thread; the working part is composed of a circumferential edge, a main cutting edge, a transverse edge, a back face and a spiral groove A; the circumferential edge is composed of a back face and a cutting edge; the positioning side surface is composed of a first precision positioning plane A, a second precision positioning plane A, a third precision positioning plane A, a fourth precision positioning plane A, a first avoidance plane, a second avoidance plane, a third avoidance plane and a fourth avoidance plane; The drill shank is composed of a clamping part, a drill rod part and a connecting part; the clamping part includes a clamping flat, a clamping cylinder and a shoulder; the drill rod part is provided with a spiral groove B and a drill rod support; the spiral groove B and the drill rod support have the same rotation direction as the spiral groove of the drill tip; the connecting part is provided with a first positioning column, a second positioning column, a positioning end face and a screw step hole.

[0005] As a preferred technical solution of the present invention, the raw material of the drill tip is a cemented carbide material, which is formed by pressing.

[0006] As a preferred technical solution of the present invention, the surface shape of the shovel back is a cylindrical surface, which is formed by pressing and is not ground after sintering, and the final surface has a sintered blank texture; the blade band is subjected to a small amount of grinding to obtain the final shape after the part is pressed and sintered, and the surface roughness does not exceed Ra0.8, and the finished product surface has a grinding texture.

[0007] As a preferred technical solution of the present invention, the shape of the chisel edge includes but is not limited to an S-shaped chisel edge and a straight chisel edge.

[0008] As a preferred technical solution of the present invention, the first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A are planes, and are parallel to each other, that is, the first precision positioning plane A is parallel to the third precision positioning plane A, and the second precision positioning plane A is parallel to the fourth precision positioning plane A; The first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A are all perpendicular to the bottom plane, and the verticality error does not exceed 0.01mm; the bottom plane is obtained by grinding, and the surface has a grinding texture.

[0009] As a preferred technical solution of the present invention, the main cutting edge is the intersection line of the back cutting edge and the spiral groove A. The back cutting edge is obtained by grinding and the surface has a grinding texture. The surface of the spiral groove A is not ground and the surface has a sintered blank texture. The connecting thread is formed by a pressing process.

[0010] As a preferred technical solution of the present invention, the positioning end face is perpendicular to the clamping cylinder of the drill shank holding part, and the verticality error does not exceed 0.01.

[0011] As a preferred technical solution of the present invention, the first positioning column and the second positioning column are symmetrically distributed about the origin of the drill shank axis, and each includes two precision positioning planes, namely the first precision positioning plane B, the second precision positioning plane B, the third precision positioning plane B, and the fourth precision positioning plane B; the four precision planes are parallel to each other, the first precision positioning plane B is parallel to the third precision positioning plane B, and the second precision positioning plane B is parallel to the fourth precision positioning plane B; the four precision positioning planes are perpendicular to the positioning end face, and the verticality error does not exceed 0.01mm.

[0012] As a preferred technical solution of the present invention, the first precision positioning plane B, the second precision positioning plane B, the third precision positioning plane B, and the fourth precision positioning plane B are matched with the first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A of the drill tip, and the matching type is interference fit with an interference amount of 0.002-0.01.

[0013] As a preferred technical solution of the present invention, when assembling the drill tip, the drill tip is inserted into the groove formed by the first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A of the drill shank, and then the screws are slowly tightened to further pull the drill tip in, and finally the bottom plane of the drill tip is completely in contact with the positioning end face of the drill shank.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The replaceable head drill of the present invention adopts a metal powder pressing and forming process. Compared with the traditional pure grinding process, the blank is close to being formed, which saves a large amount of raw materials. Since the grinding allowance is small and uniform, the working hours for grinding and the consumption of the corresponding grinding wheel are greatly reduced; at the same time, since a large number of invalid coating areas on the drill shank are reduced, the loading capacity of the coating furnace is greatly increased. Compared with the traditional integral carbide drill bit, the replaceable head drill tip greatly reduces the production cost and promotes the circular economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG1 shows a structural diagram of a drill assembly; Figure 2 shows the drill tip structure diagram; FIG3 shows a schematic diagram of the drill tip blank shape; FIG4 shows a structural diagram of the drill tip positioning surface; Figure 5 shows the structure of the drill handle; FIG6 shows a structural diagram of the drill shank clamping portion; Figure 7 shows a partial structural diagram of the drill pipe; FIG8 shows a structural diagram of the drill handle connection portion; FIG9 shows a structural diagram of the positioning column of the drill handle connection part; FIG10 shows a schematic diagram of the drill shank and drill tip connection assembly.

[0016] In the figure: 1, drill tip; 11, connecting part; 111, side positioning surface; 112, bottom plane; 113, connecting thread; 12, working part; 121, circumferential edge; 1211, back face of the shovel; 1212, edge band; 122, main cutting edge; 123, transverse edge; 124, back face; 125, spiral groove A.

[0017] 1111, first precision positioning plane A; 1112, second precision positioning plane A; 1117, third precision positioning plane A; 1118, fourth precision positioning plane A; 1113, first clearance plane; 1114, second clearance plane; 1115, third clearance plane; 1116, fourth clearance plane; 2. Drill handle; 21. Clamping part; 211. Clamping flat position; 212. Clamping cylinder; 213. Shaft shoulder; 22. Drill rod part; 221. Spiral groove B; 222. Drill rod support; 23. Connecting part; 231. First positioning column; 234. Second positioning column; 232. Positioning end surface; 233. Screw step hole; 2311, first precision positioning plane B; 2312, second precision positioning plane B; 2341, third precision positioning plane B; 2342, fourth precision positioning plane B. DETAILED DESCRIPTION

[0018] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0019] Example: See Figure 1-10 The present invention provides a technical solution: a replaceable drill head, the drill head includes a drill tip 1 and a drill handle 2 ( Figure 1 ). The raw material of the drill tip 1 is a cemented carbide material, which is formed by pressing and post-processed, and only a small amount of grinding is performed on some areas.

[0020] The drill tip 1 is divided into a connecting portion 11 and a working portion 12 ( Figure 2 ).

[0021] The connecting portion 11 of the drill tip 1 is composed of three parts, namely, a side positioning surface 111, a bottom plane 112, and a connecting thread 113 ( Figure 2 ).

[0022] The working part 12 of the drill tip 1 is composed of a circumferential edge 121, a main cutting edge 122, a chisel edge 123, a back cutting surface 124, and a spiral groove A125 ( Figure 2 ).

[0023] The circumferential blade 121 is composed of two parts: the back surface 1211 and the blade belt 1212 ( Figure 2 ). The back of the blade 1211 is a cylindrical surface, formed by pressing, and is not ground after sintering, and the final surface has a sintered texture. The blade 1212 is ground a little after the part is pressed and sintered to obtain the final shape, and the surface roughness does not exceed Ra0.8, and the finished surface has a grinding texture.

[0024] The shape of the chisel edge 123 includes but is not limited to an S-shaped chisel edge and a straight chisel edge. The pressed blank has a chisel edge of the same shape as the finished product ( Figure 3 ).

[0025] The positioning side surface 111 is composed of 4 precision positioning planes (respectively, the first precision positioning plane A1111, the second precision positioning plane A1112, the third precision positioning plane A1117, and the fourth precision positioning plane A1118) and 4 air avoidance planes (respectively, the first air avoidance plane 1113, the second air avoidance plane 1114, the third air avoidance plane 1115, and the fourth air avoidance plane 1116). The 4 precision positioning surfaces are planes and are parallel to each other, that is, the first precision positioning plane A1111 is parallel to the third precision positioning plane A1117, and the second precision positioning plane A1112 is parallel to the fourth precision positioning plane A1118. The 4 precision positioning surfaces are perpendicular to the bottom plane 112, and the verticality error does not exceed 0.01mm. The precision positioning surface is finally completed by grinding, and the surface has a grinding texture. The air avoidance surface is in the shape of a plane and is not ground. The surface has a sintered billet texture ( Figure 4 ).

[0026] The main cutting edge 122 is the intersection of the flank 124 and the spiral groove A125. The flank 124 is obtained by grinding and has a grinding texture. The surface of the spiral groove A125 is not ground and has a sintered texture. Figure 2 ).

[0027] The bottom plane 112 is obtained by grinding, and the surface has a grinding texture ( Figure 2 ).

[0028] The connecting thread 113 is formed by a pressing process without grinding, reaming, electro-corrosion or other material removal processing methods, and the final surface has a sintered blank texture ( Figure 2 ).

[0029] The drill handle 2 is composed of a clamping part 21, a drill rod part 22 and a connecting part 23 ( Figure 5 ).

[0030] The clamping part 21 includes the following elements: a clamping flat 211, a clamping cylinder 212 and a shoulder 213 ( Figure 6 ).

[0031] The drill rod portion 22 has a spiral groove B221 and a drill rod support 222; the spiral groove B221 and the drill rod support 222 have the same rotation direction as the drill tip spiral groove A125 ( Figure 7 ).

[0032] The connecting portion 23 has a first positioning column 231, a second positioning column 234, a positioning end surface 232 and a screw step hole 233. Figure 8 As shown; The positioning end surface 232 is perpendicular to the clamping cylinder 212 of the drill shank holding portion, and the verticality error does not exceed 0.01.

[0033] The first positioning column 231 and the second positioning column 234 are symmetrically distributed about the origin of the axial centerline of the drill shank, and each includes two precision positioning planes (the first precision positioning plane B2311, the second precision positioning plane B2312, the third precision positioning plane B2341, and the fourth precision positioning plane B2342). The four precision planes are parallel to each other, the first precision positioning plane B2311 is parallel to the third precision positioning plane B2341, and the second precision positioning plane B2312 is parallel to the fourth precision positioning plane B2342. The four precision positioning planes are perpendicular to the positioning end face 232, and the verticality error does not exceed 0.01mm. The four precision positioning planes of the positioning column (the first precision positioning plane B2311, the second precision positioning plane B2312, the third precision positioning plane B2341, and the fourth precision positioning plane B2342) are matched with the four precision positioning surfaces of the drill tip (the first precision positioning plane A1111, the second precision positioning plane A1112, the third precision positioning plane A1117, and the fourth precision positioning plane A1118). The matching type is interference fit, and the interference amount is 0.002-0.01 ( Fig. 9 ).

[0034] When assembling the drill tip, insert the drill tip into the groove formed by the precision positioning surfaces of the drill shank (the first precision positioning plane A1111, the second precision positioning plane A1112, the third precision positioning plane A1117, and the fourth precision positioning plane A1118), and then slowly tighten the screws to further pull the drill tip in, until the bottom plane 112 of the drill tip is completely in contact with the positioning end surface 232 of the drill shank ( Fig.10 ).

[0035] The drill tip of the present invention is divided into a working part and a connecting part. The connecting part is composed of a locking internal thread and a finely ground positioning surface. The positioning surface includes the bottom plane of the drill tip and four side surfaces. The drill tip is inserted into the drill handle and tightened to form a working drill bit. The thread provides a locking force, and the positioning surface ensures the coaxiality of the drill tip and the drill handle. The drill tip is prepared by a cemented carbide powder pressing process; The process includes: preparation of pellets, including tungsten carbide powder and cobalt powder; powder mixing and grinding, placing carbide powder and cobalt powder in a ball mill according to the designed formula, adding appropriate ball stones (carbide balls or ceramic balls, etc.), grinding media (usually alcohol, n-hexane and other organic solvents) and a small amount of forming agent / dispersant, and ball milling at a certain speed and time to make the powders of each component fully mixed, dispersed and homogenized; granulation, sending the ball-milled slurry into a spray drying tower, using high-speed rotation or compressed gas to produce fine droplets, and instantly evaporating the solvent under hot air flow to form uniform granular powder; pressing and forming, placing the prepared powder into a mold, and pressing it into a blank of the desired shape under a certain pressure; sintering, firing in a vacuum pressure sintering furnace to give the pressed part metal properties; grinding, grinding the corresponding drill tip geometry angle on a tool grinder; coating, coating a layer of special material on the drill tip surface to reduce the friction coefficient, improve wear resistance and anti-adhesion, and prevent tool oxidation.

[0036] This preparation method uses a metal powder pressing process. Compared with the traditional pure grinding process, the blank is close to forming, saving a lot of raw materials. Due to the small and uniform grinding allowance, the grinding hours and the consumption of the corresponding grinding wheel are greatly reduced; at the same time, due to the reduction of a large number of invalid coating areas on the drill shank, the loading capacity of the coating furnace is greatly increased. Compared with traditional solid carbide drill bits, the replaceable drill tip greatly reduces production costs and promotes a circular economy.

[0037] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A replaceable drill head, comprising a drill head and a drill shank, characterized in that: The drill tip and the drill shank are separable and connected to the drill shank by using the internal thread and positioning surface of the drill tip connection part; The drill tip is composed of two parts, namely a working part and a connecting part; the connecting part is composed of three parts, namely a positioning side surface, a bottom plane and a connecting thread; the working part is composed of a circumferential edge, a main cutting edge, a transverse edge, a back face and a spiral groove A; the circumferential edge is composed of a back face and a cutting edge; the positioning side surface is composed of a first precision positioning plane A, a second precision positioning plane A, a third precision positioning plane A, a fourth precision positioning plane A, a first avoidance plane, a second avoidance plane, a third avoidance plane and a fourth avoidance plane; The drill shank is composed of a clamping part, a drill rod part and a connecting part; the clamping part includes a clamping flat, a clamping cylinder and a shoulder; the drill rod part is provided with a spiral groove B and a drill rod support; the spiral groove B and the drill rod support have the same rotation direction as the spiral groove of the drill tip; the connecting part is provided with a first positioning column, a second positioning column, a positioning end face and a screw step hole.

2. The replaceable head drill bit according to claim 1, characterized in that: The raw material of the drill tip is a cemented carbide material, which is formed by pressing.

3. The replaceable head drill bit according to claim 1, characterized in that: The surface shape of the shovel back is a cylindrical surface, which is formed by pressing and is not ground after sintering. The final surface has a sintered blank texture; the blade band is subjected to a small amount of grinding after the part is pressed and sintered to obtain the final shape, and the surface roughness does not exceed Ra0.8, and the finished product surface has a grinding texture.

4. The replaceable head drill bit according to claim 1, characterized in that: The shape of the chisel edge includes but is not limited to an S-shaped chisel edge and a straight chisel edge.

5. The replaceable head drill bit according to claim 1, characterized in that: The first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A are planes, and are parallel to each other, that is, the first precision positioning plane A is parallel to the third precision positioning plane A, and the second precision positioning plane A is parallel to the fourth precision positioning plane A; The first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A are all perpendicular to the bottom plane, and the verticality error does not exceed 0.01mm; the bottom plane is obtained by grinding, and the surface has a grinding texture.

6. The replaceable head drill bit according to claim 1, characterized in that: The main cutting edge is the intersection line of the back tool face and the spiral groove A. The back tool face is obtained by grinding and has a grinding texture on the surface. The surface of the spiral groove A is not ground and has a sintered texture. The connecting thread is formed by a pressing process.

7. The replaceable head drill bit according to claim 1, characterized in that: The positioning end face is perpendicular to the clamping cylinder of the drill shank holding part, and the verticality error does not exceed 0.

01.

8. The replaceable head drill bit according to claim 1, characterized in that: The first positioning column and the second positioning column are symmetrically distributed about the origin of the drill shank axis, and each includes two precision positioning planes, namely the first precision positioning plane B, the second precision positioning plane B, the third precision positioning plane B, and the fourth precision positioning plane B; the four precision planes are parallel to each other, the first precision positioning plane B is parallel to the third precision positioning plane B, and the second precision positioning plane B is parallel to the fourth precision positioning plane B; the four precision positioning planes are perpendicular to the positioning end face, and the verticality error does not exceed 0.01mm.

9. The replaceable head drill according to claim 8, characterized in that: The first precision positioning plane B, the second precision positioning plane B, the third precision positioning plane B, and the fourth precision positioning plane B cooperate with the first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A of the drill tip, and the cooperation type is interference fit with an interference amount of 0.002-0.

01.

10. The replaceable head drill bit according to claim 1, characterized in that: When assembling the drill tip, insert the drill tip into the groove formed by the first precision positioning plane A, the second precision positioning plane A, the third precision positioning plane A, and the fourth precision positioning plane A of the drill shank, then slowly tighten the screws to further pull the drill tip in, and finally the bottom plane of the drill tip is completely in contact with the positioning end face of the drill shank.

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