TW202403194A - Self-drilling screw structure and manufacturing method thereof capable of reducing the left-right shaking problem caused by the self-drilling screw structure thereby increasing the stability of the drilling process - Google Patents

Abstract

The present invention provides a self-drilling screw structure and a manufacturing method thereof. The manufacturing method includes: providing a screw body, forming a self-drilling screw stem section, forming a concave neck, forming a self-drilling cutting edge, and forming a thread. The self-drilling screw structure includes a screw head part and a screw stem part. The screw stem part is provided with a threaded screw stem section, a self-drilling screw stem section and a drill screw stem section in sequence. The threaded screw stem section has a threaded rod diameter and the thread. The self-drilling screw stem section has a self-drilling rod diameter, a plurality of self-drilling cutting edges, and a plurality of self-drilling chip flutes arranged in a staggered manner. From an end connected to the self-drilling screw stem section, the drill screw stem section is sequentially provided with an cambered concave neck part, a positioning part and a tip part, and the drill screw stem section is convexly formed with a plurality of drill cutting edges and the drill chip flutes arranged in a staggered manner, wherein the concave neck part has one end connected to the self-drilling cutting edges, and the other end connected to the drill cutting edges so as to reduce the left-right shaking problem caused by the self-drilling screw structure and to increase the stability of the drilling process.

Description

Drill tail screw structure and manufacturing method

The present invention relates to a drill tail screw, in particular to a drill tail screw structure and a manufacturing method thereof which have a curved surface design and whose cutting edges are not connected and whose chip removal grooves can quickly discharge chips.

Conventional drill tail screws are generally directly punched and formed with corresponding chip flutes and cutting edges. Since these chip flutes are formed by stamping a stamping die on a flat surface, the chip flutes can only be formed on a flat surface. The design extends vertically or slightly obliquely on the plane, but this conventional drill tail screw has the advantage of mass production.

However, although the conventional drill tail screws formed by direct stamping have the advantage of mass production, after the fixed point of the front end is drilled, due to the poor chip removal ability of the drill tail screws formed by the conventional stamping method, it is difficult to carry out the process. During the drilling process, it is easy to shift and cause the drilling position to deviate from the predetermined position. In view of this, the inventor has devoted himself to research and combined with what he has learned to solve the above problems and propose a drill tail screw structure that produces two different discontinuous cutting edges in the stamping method and the thread rolling method to overcome the deficiencies of the conventional knowledge.

The purpose of the present invention is to form different cutting edges by stamping and rolling, and connect the cutting edges formed by different ways by a concave neck, so as to solve the problem of the conventional drill tail screws in the above-mentioned prior art that cannot be effectively arranged. The problem of poor stability during chipping and hole expansion.

In order to achieve the above object, the present invention provides a manufacturing method of a drill tail screw, which is used to manufacture a drill tail screw that forms threads with the same thread outer diameter at different rod diameter widths. The manufacturing method of the drill tail screw is The method includes: providing a screw body having a screw head and a screw part protrudingly extending from one side of the screw head along the axial direction of the screw head; forming a drill tail screw section to connect the screw part A threaded screw section, a drill tail screw section, and a drill bit screw section are formed in sequence from the joint of the screw head, wherein the threaded screw section has a threaded rod diameter, and the drill tail screw section has a drill tail rod diameter; A concave neck is formed, and a concave neck, a positioning portion and a tip are formed from the drill bit screw section by stamping. The drill bit screw section is adjacent to the drill tail screw section and the concave section is formed in sequence along the axial direction. The shaped neck portion, the positioning portion and the end portion, wherein the tip portion is axially tapered from the end adjacent to the positioning portion toward the other end to form a static point, and the concave neck portion is formed from the adjacent end of the drill. The end of the tail screw rod section is concave along the axial direction toward the positioning portion to form an arc surface, and the drill screw rod section forms a plurality of drill bit cutting edges and a plurality of drill bit chip removal grooves along the axial direction from the static point toward the concave neck. The chip flutes of the drill bit are each located between the adjacent drill bit cutting edges; a drill tail cutting edge is formed, and the drill tail screw section is connected to the concave neck end to form a plurality of drill tail cutting edges and a plurality of drill bits in a rolling manner. The tail chip flutes are each located between the adjacent drill tail cutting edges, and the drill tail cutting edges each have an outer diameter of the drill tail cutting edge; and a thread is formed from The threaded screw section connects the end of the drill tail screw section to form a thread in a threading manner, wherein the thread extends axially to the screw head, and the thread has a thread outer diameter; wherein, the drill tail rod The diameter system is smaller than the diameter of the threaded rod and greater than zero, and one end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill bit cutting edges.

Further, the concave neck portion gradually expands in the axial direction toward the drill tail screw section and the positioning portion respectively, and the end of the threaded screw section adjacent to the drill tail screw section tapers in the direction of the drill tail screw section.

Further, each of the drill tail cutting edges has a first helical surface, a second helical surface and a drill tail helix angle, wherein the connection between each first helical surface and each second helical surface forms a The drill tail helix angle.

Further, the drill tail cutting edges have an asymmetric structure, and the first distance of each first helical surface of the drill tail cutting edges from the drill tail helix angle to the drill tail screw segment surface is smaller than each first helical surface of the drill tail cutting edges. The second distance of the second helical surface from the drill tail helix angle to the drill tail screw segment surface is greater than zero.

Further, the outer diameter of the drill tail cutting edges is less than or equal to the outer diameter of the thread cutting edge.

Furthermore, the tail screw structure manufactured by the manufacturing method of the drill screw mainly includes a screw head and a screw rod portion extending outward from the screw head. The screw rod portion extends from the joint of the screw head along the A threaded screw section, a drill tail screw section, and a drill bit screw section are formed in sequence in the axial direction, and the threaded screw section has a threaded rod diameter and a thread protruding on the threaded screw section, and the drill tail screw section has A drill tail rod diameter, a plurality of drill tail cutting edges protruding from the drill tail screw section and a plurality of drill tail chip flutes located between the adjacent drill tail cutting edges, each of the drill tail cutting edges having A drill tail cutting edge has an outer diameter, and the drill bit screw section is self-connected with the drill tail screw section end and is sequentially provided with a concave neck, a positioning portion and a tip portion along its axial direction. The tip portion is self-connected to the positioning portion. The end of the drill bit tapered toward the other end along the axial direction to form a static point, and the concave neck is concave from the end of the adjacent drill tail screw segment along the axial direction toward the positioning portion to form an arc surface, and the drill bit screw A segment protrudes from the static point along the axial direction toward the concave neck to form a plurality of drill bit cutting edges and a plurality of drill bit chip removal grooves. Each of the drill bit chip removal grooves is located between the adjacent drill bit cutting edges, wherein the drill bit chip removal grooves are located between the adjacent drill bit cutting edges. The diameter of the drill tail rod is smaller than the diameter of the threaded rod and greater than zero, and one end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill bit cutting edges.

Further, the concave neck portion of the drill bit screw section gradually expands along the axial direction toward the drill tail screw section and the positioning portion respectively, and the drill bit flutes pass from the static point through the tip portion and the positioning portion. The concave neck extends partially to part.

The screw system first performs the step of forming a drill tail screw section so that the drill tail rod diameter of the drill tail screw section is smaller than the threaded rod diameter of the threaded screw section, and then performs the step of forming a concave neck.

The screw system simultaneously implements the step of forming a drill tail screw rod section and the step of forming a concave neck.

Therefore, the present invention has the following beneficial effects compared with the prior art:

1. The manufacturing method of the drill tail screw of the present invention is mainly to form the concave neck, the positioning part, the tip part, the drill cutting edges and the drill chip flutes by stamping on the drill screw section. The drill tail cutting edges and the drill tail chip removal grooves are then formed by rolling teeth, and the drill bit cutting edges at one end and the drill tail cutting edges at the other end are respectively connected by the concave neck. In this way, cutting edge structures with different manufacturing processes are formed to increase the manufacturing yield.

2. The structure of the drill screw manufactured by the manufacturing method of the drill tail screw of the present invention is mainly that there is a concave neck between the drill bit cutting edges and the drill tail cutting edges, whereby the drill bit cuts When the chips generated by the cutting edge are discharged through the drill bit chip discharge grooves, the chips are randomly sent to the drill tail chip discharge grooves of the drill tail screw section when passing through the concave neck. In this way, Chips will not accumulate due to the drill tail chip removal groove and cause left and right shaking problems, which increases the stability of the drill tail screw structure when drilling.

We hereby enumerate several better implementation modes regarding the technical features and operation methods of this application, and describe them below with illustrations for reference in the review. Furthermore, the proportions of the drawings in the present invention may not be drawn according to actual proportions for the convenience of explanation, and the proportions in the drawings are not intended to limit the scope of protection claimed by the present invention.

Regarding the content of the present invention, please refer to Figures 1 to 10, which illustrate embodiments of the present invention. The present invention provides a method for manufacturing a drill tail screw, which is used to manufacture an outer screw with the same thread formed in different rod diameter widths. Please refer to Figure 2-1 to Figure 3 for the manufacturing method of drill tail screws with diameter threads. The manufacturing method of the drill tail screws includes:

A screw body is provided. The screw body 10 is provided with a screw head 11 and a screw rod portion 12 protrudingly extending from one side of the screw head 11 along the axial direction Z of the screw head 11 .

A drill tail screw section is formed, and the screw section 12 is sequentially formed from the connection point of the screw head 11 to a threaded screw section 121, the drill tail screw section 122, and a drill bit screw section 123, wherein the threaded screw section 121 has A threaded rod diameter D1, the drill tail screw section 122 has a drill tail rod diameter D2, wherein the drill tail screw section 122 and the drill bit screw section 123 in this embodiment are formed by stamping.

A concave neck is formed. Please refer to Figure 3 again. A concave neck 1231, a positioning portion 1232 and a tip portion 1233 are formed by punching from the drill screw section 123. The drill screw section 123 is formed from the adjacent The end of the drill tail screw section 122 is sequentially formed with the concave neck 1231, the positioning part 1232 and the tip part 1233 along the axial direction Z, wherein the tip part 1233 is formed along the axial direction Z from the end adjacent to the positioning part 1232. It tapers toward the other end to form a static point P, and the concave neck 1231 gradually expands along the axial direction Z toward the drill tail screw section 122 and the positioning portion 1232 respectively, and from the adjacent drill tail screw section 122 The end of the threaded screw section 121 is concave toward the positioning portion 1232 along the axial direction Z to form an arc surface, and the end of the threaded screw section 121 adjacent to the drill tail screw section 122 is tapered in the direction of the drill tail screw section 122, and the drill screw section 123 starts from The static point P forms a plurality of drill bit cutting edges 1234 and a plurality of drill bit chip flutes 1235 along the axial direction Z toward the concave neck 1231. Each of the drill bit chip flutes 1235 is located between the adjacent drill bit cutting edges 1234. In addition, the drill chip flutes 1235 extend from the static point P through the tip portion 1233 and the positioning portion 1232 to part of the concave neck 1231 .

A drill tail cutting edge is formed, and a plurality of drill tail cutting edges 1221 and a plurality of drill tail chip removal grooves 1222 are formed from the end of the drill tail screw section 122 to the concave neck 1231 by rolling teeth. The drill tail chip removal grooves 1222 Each of the drill tail cutting edges 1221 is located between the adjacent drill tail cutting edges 1221, and each of the drill tail cutting edges 1221 has a drill tail cutting edge outer diameter R1, and each of the drill tail cutting edges 1221 has a first helical surface. 1223. A second helical surface 1224 and a drill tail helix angle α, wherein the connection between each first helical surface 1223 and each second helical surface 1224 forms a drill tail helix angle α, and the drill tail helix angle α The tail cutting edge 1221 has an asymmetric structure, and the first distance d1 of each first helical surface 1223 of the drill tail cutting edges 1221 from the drill tail helix angle α to the surface of the drill tail screw section 122 is less than The second distance d2 from the second helical surface 1224 from the drill tail helix angle α to the surface of the drill tail screw section 122 is greater than zero.

A thread is formed, and a thread 1211 is formed from the threaded screw section 121 to the end of the drill tail screw section 122 in a rolling manner, wherein the thread 1211 extends spirally along the axial direction Z to the screw head 11, and the thread 1211 There is a thread outer diameter R2, and the outer diameter R1 of the drill tail cutting edge is smaller than or equal to the outer diameter R2 of the thread cutting edge.

Among them, please refer to Figure 1 first. The screw body 10 can perform the steps of forming the drill tail screw section and the step of forming a concave neck at the same time. Alternatively, please refer to Figure 10. The screw body 10 can This system first performs the step of forming the drill tail screw section to make the drill tail rod diameter D2 of the drill tail screw section 122 smaller than the threaded rod diameter D1 of the threaded screw section 122, and then performs the step of forming a concave neck. Steps, the screw body 10 in this embodiment performs the step of forming the drill tail screw section and the step of forming a concave neck at the same time, so that the screw body 10 forms the concave neck on the drill screw section 123 by punching. When the part 1231, the positioning part 1232 and the tip part 1233 are formed, the drill tail screw section 122 is formed at the same time.

Furthermore, the drill screw structure manufactured by the drill screw manufacturing method mainly includes the screw head 11 and the screw part 12 extending outward from the screw head 11, and the screw part 12 extends outward from the screw head 11. The threaded screw section 121, the drill tail screw section 122, and the drill bit screw section 123 are formed sequentially along the axial direction Z from the connection point of the screw head 11, and the threaded screw section 121 has the threaded rod diameter D1 With the thread 1211 protruding on the threaded screw section 121, the drill tail screw section 122 has the drill tail rod diameter D2, the drill tail cutting edges 1221 protruding on the drill tail screw section 122 and located at the corresponding The drill tail cutting edges 1221 are adjacent to the drill tail cutting edges 1221. Each of the drill tail cutting edges 1221 has an outer diameter R1 of the drill tail cutting edge, and the drill screw section 123 is self-connected to the drill tail. The end of the screw section 122 is sequentially provided with the concave neck 1231, the positioning part 1232 and the tip part 1233 along the axial direction Z. The tip part 1233 is from the end adjacent to the positioning part 1232 to the other end along the axial direction Z. The static point P is formed by tapering, and the concave neck 1231 is concave from the adjacent end of the drill tail screw section 122 along the axial direction Z toward the positioning portion 1232 to form the arc surface, and the drill bit screw section 123 is formed from the The static point P protrudes toward the concave neck 1231 along the axial direction Z to form the drill bit cutting edges 1234 and the drill bit chip removal grooves 1235. The drill bit chip removal grooves 1235 are each located on the adjacent drill bit cutting edges. 1234 rooms;

Among them, the diameter D2 of the drill tail rod is smaller than the diameter D1 of the threaded rod and greater than zero, and one end of the concave neck 1231 is connected to the drill tail cutting edges 1221, and the other end is connected to the drill bit cutting edges 1234. In this embodiment In the step of forming a drill tail screw section, first make the drill tail rod diameter D2 of the drill tail screw section 122 smaller than the threaded rod diameter D1 of the threaded screw section 121, but it is not limited to this. In the step of forming a concave neck, the tail screw structure can also make the drill tail rod diameter D2 of the drill tail screw section 122 smaller than the threaded rod diameter D1 of the threaded screw section 121. In addition, the drill tail screw The length of the section 122 will affect the thickness of the workpiece that the drill tail screw can drill. Therefore, the drill tail screw section 122 is greater than or equal to the thickness of the workpiece, and the screw head screw section 123 is used to allow the drill tail screw to drill. The hole workpiece is positioned, so the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck 1231 is less than or equal to 0.86 and greater than or equal to 0.62, and in this embodiment, the drill tail cutting edge When the M8 screw specification has an outer diameter R1, the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck 1231 is 0.75, and the outer diameter R1 of the drill tail cutting edge is 1/4 inch. When the screw specification is 7/32 inches, the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck 1231 is 0.625, and the outer diameter R1 of the drill tail cutting edge is 7/32 inches screw specifications. , the ratio of the total length of the positioning portion 1232 and the tip portion 1233 to the length of the concave neck 1231 is 0.714, but is not limited to this.

Also, please refer to Figures 2 to 5. The screw body 10 is designed so that the outer diameter R1 of the drill end cutting edge 1221 is substantially the same as the outer diameter R2 of the thread 1211, so it will The drill tail rod diameter D2 of the drill tail screw section 122 is made smaller than the threaded rod diameter D1 of the threaded screw section 121. In this way, during the step of forming a drill tail cutting edge, the drill tail screw section 122 has The drill tail cutting edge outer diameter R1 of the drill tail cutting edge 1221 is substantially the same as the thread outer diameter R2 of the thread 1211. This makes the drill tail screw structure easy to drill into the workpiece and external chips. In addition, the drill bit cutting edges 1234 and the drill tail cutting edge 1221 are respectively formed on the drill bit screw section 123 and the drill tail screw section 122, and the drill bit cutting edges 1234 and the drill tail cutting edges 1221 are each provided with the concave shape. Neck 1231. In this way, when drilling the workpiece, the chips discharged from the drill chip flute 1235 will pass through the drill chip flute 1234 and then pass through the concave necks 1231, and then from the drill tail. At least one of the drill tail chip flutes 1222 of the screw section 122 is discharged. In this way, not only can the pressure of the chips in the drill bit chip flutes 1235 and the drill tail chip flutes 1222 be reduced, but also the pressure of the chips can be discharged through the drill tail chip flutes 1222 . The drill tail cutting edge 1221 carries out the second cutting of the chips from the drill bit chip flutes 1235, so that the chips can be discharged smoothly; in addition, the first helical surfaces 1223 of the drill tail cutting edge 1221 and The circumferential surface of the drill tail screw section 122 has different first distances d2. Therefore, the drill tail chip flutes 1222 and the drill tail cutting edges 1221 are each asymmetrically designed to increase their service life.

To sum up, the manufacturing method of the drill tail screw of the present invention mainly uses stamping to form the concave neck 1231, the positioning part 1232, the tip part 1233, the drill cutting edges 1234 and the drill bits. The drill screw section 123 of the chip removal groove 1235 is further formed with the drill tail cutting edges 1221 and the drill tail chip removal grooves 1222 by rolling teeth, and the concave neck portions 1231 are respectively connected to one end of the drill bit screw segments 123 . The drill bit cutting edge 1234 and the drill tail cutting edges 1221 at the other end thereby form structures of the drill bit cutting edge 1234 and the drill tail cutting edge 1221 with different processes, thereby increasing the manufacturing yield, and the drill bit cutting edge 1234 and the drill tail cutting edge 1221 are formed with different processes. The drill tail screw structure produced by the manufacturing method of the tail screw is mainly due to the concave neck 1231 between the drill bit cutting edges 1234 and the drill tail cutting edges 1221, whereby the drill bit cutting edges 1234 produce When the chips are discharged through the drill bit chip discharge grooves 1235, the chips can be randomly sent to the drill tail chip discharge grooves 1222 of the drill tail screw section 122 when passing through the concave neck 1231, so that , debris will not accumulate due to the drill tail chip removal groove 1222, thereby reducing the left and right shaking problem of the drill tail screw structure, and increasing the stability of the drill tail screw structure when drilling.

10: Screw body 11:Screw head 12:Screw part 121:Threaded screw section 1211:Thread 122: Drill tail screw section 1221: Drill tail cutting edge 1222:Drill tail chip groove 1223:First spiral surface 1224:Second helix 123:Drill screw section 1231: Concave neck 1232: Positioning Department 1233: Tip part 1234:Drill cutting edge 1235: Drill chip flute P: Quiet Z:Axis D1: threaded rod diameter D2: Drill tail rod diameter R1: outer diameter of drill tail cutting edge R2: Thread outer diameter α:Drill tail helix angle d1: first distance d2: second distance

Figure 1 is a schematic flow chart of the manufacturing method of the drill tail screw of the present invention. Figures 2-1 to 2-3 are schematic diagrams of the process and corresponding forming structure of the manufacturing method of the drill tail screw of the present invention. Figure 3: is a schematic side view of the drill tail screw structure of the present invention. Figure 4: An enlarged view of circle A in Figure 3. Figure 5: An enlarged view of circle B in Figure 3. Figure 6: is a three-dimensional schematic diagram of the drill tail screw structure of the present invention. Figure 7 is a schematic three-dimensional view of the drill tail screw structure of the present invention from another perspective. Figure 8 is a schematic cross-sectional view of the drill tail screw structure of the present invention. Figure 9: An enlarged view of the section circled C in Figure 8. Figure 10: is a schematic flow chart of another manufacturing method of the drill tail screw of the present invention.

11:Screw head

12:Screw part

121:Threaded screw section

1211:Thread

122: Drill tail screw section

1221: Drill tail cutting edge

1222:Drill tail chip groove

1223:First spiral surface

1224:Second helix

123:Drill screw section

1231: Concave neck

1232: Positioning Department

1233: Tip part

1234:Drill cutting edge

1235: Drill chip flute

P: Quiet

Z:Axis

R1: outer diameter of drill tail cutting edge

R2: Thread outer diameter

Claims (10)

A manufacturing method of a drill tail screw, which is used to manufacture a drill tail screw with threads of the same thread outer diameter formed in different rod diameter widths. The manufacturing method of the drill tail screw includes: Provide a screw body having a screw head and a screw rod portion protrudingly extending from one side of the screw head along the axial direction of the screw head; A drill tail screw section is formed, and the screw section is sequentially formed from the connection point of the screw head to form a threaded screw section, a drill tail screw section, and a drill bit screw section, wherein the threaded screw section has a threaded rod diameter, and the The drill tail screw section has a drill tail rod diameter; A concave neck is formed, and a concave neck, a positioning portion and a tip are formed from the drill bit screw section by stamping. The drill bit screw section includes the drill bit screw section in sequence along the axial direction from the end adjacent to the drill tail screw section. The concave neck portion, the positioning portion and the tip portion, wherein the tip portion tapers from the end adjacent to the positioning portion toward its other end in the axial direction to form a static point, and the concave neck portion is formed from the end adjacent to the positioning portion. The end of the drill tail screw rod section is concave along the axial direction toward the positioning portion to form an arc surface, and the drill screw rod section forms a plurality of drill bit cutting edges and a plurality of drill bit chip removal grooves along the axial direction from the static point toward the concave neck. The chip flutes of the drill bits are located between the cutting edges of the adjacent drill bits; A drill tail cutting edge is formed, and the drill tail screw section is connected to the concave neck end to form a plurality of drill tail cutting edges and a plurality of drill tail chip flutes in a rolling manner. The drill tail chip flutes are located adjacent to each other. between the drill tail cutting edges, and the drill tail cutting edges each have a drill tail cutting edge outer diameter; and A thread is formed from the threaded screw section to the end of the drill tail screw section in a rolling manner, wherein the thread extends axially spirally to the screw head, and the thread has an outer diameter; Wherein, the diameter of the drill tail rod is smaller than the diameter of the threaded rod and greater than zero; One end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill bit cutting edges. The manufacturing method of a drill tail screw as described in claim 1, further, the concave neck portion is gradually expanded in the axial direction toward the drill tail screw section and the positioning portion respectively, and the threaded screw section is adjacent to the drill tail screw section. The end of the segment is tapered toward the direction of the drill tail screw segment. The manufacturing method of drill tail screws as described in claim 1, further, each of the drill tail cutting edges has a first helical surface, a second helical surface and a drill tail helix angle, wherein each of the first helical surfaces The connection between the helical surface and each second helical surface forms a drill tail helix angle. As for the manufacturing method of the drill tail screw described in claim 1, further, the screw system first performs the step of forming the drill tail screw section, so that the drill tail rod diameter of the drill tail screw section is smaller than that of the threaded screw section. This threaded rod diameter is followed by the step of forming a concave neck. As for the manufacturing method of the drill tail screw described in claim 1, further, the screw system simultaneously implements the step of forming the drill tail screw section and the step of forming a concave neck. A drill tail screw structure, which mainly includes: The head of a snail; A screw part extending outward from the screw head. The screw part forms a threaded screw section, a drill tail screw section, and a drill bit screw section in sequence along the axial direction from the joint of the screw head. The threaded screw section It has a threaded rod diameter and a thread protruding on the threaded screw section. The drill tail screw section has a drill tail rod diameter, a plurality of drill tail cutting edges protruding on the drill tail screw section and a plurality of adjacent drill tail cutting edges. The drill tail chip flutes between the drill tail cutting edges, each of the drill tail cutting edges has an outer diameter of the drill tail cutting edge, and the drill bit screw section is self-connected with the drill tail screw section end along its axial direction. A concave neck portion, a positioning portion and a tip portion are provided in sequence. The tip portion is tapered from the end adjacent to the positioning portion toward the other end in the axial direction to form a static point, and the concave neck portion is formed from the adjacent end of the positioning portion. The end of the drill tail screw section is concave along the axial direction toward the positioning portion to form an arc surface, and the drill screw section is convex from the static point along the axial direction toward the concave neck to form a plurality of drill bit cutting edges and a plurality of drill bit chip removal. The chip removal grooves of these drill bits are each located between the cutting edges of the adjacent drill bits; Wherein, the diameter of the drill tail rod is smaller than the diameter of the threaded rod and greater than zero; One end of the concave neck is connected to the drill tail cutting edges, and the other end is connected to the drill bit cutting edges. The drill tail screw structure as described in claim 6, wherein the concave neck portion of the drill bit screw section gradually expands in the axial direction toward the drill tail screw section and the positioning portion respectively, and the drill bit chip removal grooves are The concave neck extends from the static point through the tip part and the positioning part to part of the concave neck. The drill tail screw structure of claim 6, wherein each of the drill tail cutting edges has a first helical surface, a second helical surface and a drill tail helix angle, and each of the first helical surface and each A connection point of the second helical surface forms a helix angle of the drill tail. As for the drill tail screw structure described in claim 8, further, the drill tail cutting edges are of an asymmetric structure, and each first helical surface of the drill tail cutting edges is from the drill tail helix angle to the The first distance of the surface of the drill tail screw section is smaller than the second distance of each second helical surface from the drill tail helix angle to the surface of the drill tail screw section and is greater than zero. The drill tail screw structure as described in claim 6, wherein the outer diameter of the drill tail cutting edges is less than or equal to the outer diameter of the thread cutting edges.

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