A new type of cooling back-pull crown drill

Abstract

The present invention provides a novel cooling back-pull crown drill bit, which enables the crown drill bit to be locked through the back-pull structure and the drill rod, so that the locking is stable and reliable, and the coolant directly cools the cutting edge of the crown drill bit, and the cooling effect is good. The drill rod includes a working part, a neck, and a shank. The outer periphery of the working part of the drill rod is provided with a spiral chip removal groove and a knife back. The front end center position of the working part is concave to form a crown cutter head positioning cavity. The crown cutter head is embedded in the crown cutter head positioning cavity. The crown cutter head includes a locking threaded hole concave at the rear end. The locking threaded hole of the crown cutter head is connected to the front end thread of the tightening screw. The axial inner end of the crown cutter head positioning cavity of the working part is provided with a concave center threaded hole. The rear end thread of the tightening screw is connected to the concave center threaded hole. The front end thread and the rear end thread of the tightening screw have opposite rotation directions. The main cooling hole is provided at the axial center position of the drill rod.

Description

Technical Field

[0001] The invention relates to the technical field of cutting tool structures, in particular to a novel cooling back-pull type crown drill. Background Art

[0002] With the rapid development of engineering machinery, heat exchangers, wind power and other industries, large-diameter hole processing is increasing. Solid carbide drill bits are expensive and have high processing costs. Crown drill bits are a combination of carbide or other high-performance materials for the head and alloy steel for the drill rod. They are suitable for large-diameter hole processing and have the advantages of low cost and large processing range.

[0003] At present, there are many combinations of the head and drill rod of the crown drill bit. The cooling method is that the cooling holes spray toward the inclined surfaces on both sides, which cannot directly cool the cutting edge of the crown drill bit and has a poor cooling effect. Summary of the invention

[0004] In view of the above problems, the present invention provides a new type of cooling back-pull crown drill bit, which enables the crown drill bit to be locked through the back-pull structure and the drill rod, so that the locking is stable and reliable, and the coolant directly cools the cutting edge of the crown drill bit, resulting in good cooling effect.

[0005] A novel cooling and rear-pull crown drill, characterized in that it comprises a drill rod and a crown cutter head, the drill rod comprises a working part, a neck and a shank, the outer periphery of the working part of the drill rod is provided with a spiral chip removal groove and a knife back, the front end center position of the working part is concave to form a crown cutter head positioning cavity, the crown cutter head is embedded in the crown cutter head positioning cavity, the crown cutter head comprises a locking threaded hole concave at the rear end, the locking threaded hole of the crown cutter head is connected to the front end thread of a tightening screw, the axial inner end of the crown cutter head positioning cavity of the working part is provided with a concave center threaded hole, the rear end thread of the tightening screw is connected to the concave center threaded hole, the pull The front end thread and the rear end thread of the tightening screw have opposite rotation directions, a main cooling hole is arranged at the axial center position of the drill rod, the inner concave center threaded hole is connected to the main cooling hole, at least two bypass pipelines are arranged on the front end periphery of the main cooling hole facing the working part, two liquid outlets are arranged at the position of the end stop surface of the main cooling hole facing the positioning cavity of the crown cutter head, and a liquid outlet notch is arranged at the position corresponding to the liquid outlet, the rear end face of the crown cutter head in the assembled state and the end stop face plane of the positioning cavity of the crown cutter head are arranged tightly; the crown cutter head and the working part of the drill rod are assembled in place to form an integral drill bit structure.

[0006] It is further characterized by:

[0007] The obtuse-angled positioning surfaces on both sides of the tooth crown cutter head are symmetrical structures;

[0008] The cross section of the spiral chip removal groove is a U-shaped groove structure, and a protective blade edge is arranged in the spiral chip removal groove. The groove body structure of the U-shaped groove makes the chip space large and the chip removal smooth. At the same time, the strength of the blade back is high, and the feed speed during processing is fast. The protective blade edge reduces the groove front angle of the outer diameter part, preventing the drill rod from participating in the cutting under harsh working conditions and causing the blade to break;

[0009] Two bypass pipelines are arranged on the outer periphery of the front end of the main cooling hole facing the working part to form a Y-shaped passage outlet, and the Y-shaped passage outlet is connected to the liquid outlet through a branch respectively;

[0010] The handle of the drill rod has a side pressure surface inclined at 2°, which is locked by a side pressure locking screw of the tool handle. When in use, the tool handle clamps the handle to transmit the power of the machine tool, so that the tool rotates and has cutting ability;

[0011] The neck is a combination of a cone and a cylinder, which can prevent chips from splashing and hitting the tool handle and the machine tool spindle during operation, thus playing a protective role.

[0012] After the present invention is adopted, the locking threaded hole of the crown cutter head is connected to at least a part of the front end thread of the tightening screw. During pre-installation, a certain installation gap for the front end thread is left. Then the crown cutter head is positioned in the crown cutter head positioning cavity, and the rear end thread of the tightening screw is connected to the concave center threaded hole. After the hexagonal wrench penetrates the main cooling hole, the tightening screw is tightened, so that the rear end thread of the tightening screw is connected to the concave center threaded hole. At the same time, the rear end face of the crown cutter head and the end stop surface plane of the crown cutter head positioning cavity are arranged in close contact to complete the tightening and locking. It enables the crown drill bit to be locked through the rear-pull structure and the drill rod, so that the locking is stable and reliable. In addition, the coolant is connected to the liquid outlet and the liquid outlet gap through the main cooling hole, so that the coolant directly cools the cutting edge of the crown drill bit, and the cooling effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0014] Figure 2 It is a schematic diagram of the exploded structure of the present invention (partial cross-section);

[0015] Figure 3 for Figure 1 The left view structural diagram of ;

[0016] Figure 4 for Figure 2 Schematic diagram of AA cross-sectional structure;

[0017] Figure 5 for Figure 2 Schematic diagram of BB cross-sectional structure;

[0018] The names corresponding to the serial numbers in the figure are as follows:

[0019] Drill rod 1, working part 11, neck 12, shank 13, spiral chip groove 14, knife back 15, tooth crown cutter head positioning cavity 16, concave center threaded hole 17, protective knife edge 18, side pressure surface 19, tooth crown cutter head 2, locking threaded hole 21, obtuse angle positioning surface 22, tightening screw 3, front end thread 31, rear end thread 32, main cooling hole 4, bypass pipeline 5, liquid outlet 6, liquid outlet notch 7, branch 8. DETAILED DESCRIPTION

[0020] A new type of cooling back-pull crown drill, see Figure 1-Figure 5 :It includes a drill rod 1 and a crown cutter head 2. The drill rod 1 includes a working part 11, a neck part 12, and a shank part 13. The outer periphery of the working part 11 of the drill rod 1 is provided with a spiral chip removal groove 14 and a blade back 15. The front end center position of the working part 11 is concave to form a crown cutter head positioning cavity 16. The crown cutter head 2 is embedded in the crown cutter head positioning cavity 16. The crown cutter head 2 includes a locking threaded hole 21 concave at the rear end. The locking threaded hole 21 of the crown cutter head 21 is connected to the front end thread 31 of the tightening screw 3. The axial inner end of the crown cutter head positioning cavity 16 of the working part 11 is provided with a concave center threaded hole 17. The rear end thread 32 of the tightening screw 3 is connected to the concave center threaded hole 17. The tightening screw The front end thread 31 and the rear end thread 32 of the nail 3 are in opposite directions, a main cooling hole 4 is provided at the axial center position of the drill rod 1, the concave center threaded hole 17 is connected to the main cooling hole 4, at least two bypass pipes 5 are provided on the front end periphery of the main cooling hole 4 facing the working part 11, two liquid outlets 6 are provided at the position of the end stop surface of the main cooling hole 4 facing the crown cutter head positioning cavity 16, and a liquid outlet notch 7 is provided at the position corresponding to the liquid outlet 6 of the crown cutter head 2, and the rear end surface of the crown cutter head 2 in the assembled state is arranged in close contact with the end stop surface plane of the crown cutter head positioning cavity 16; after the crown cutter head 2 and the working part 11 of the drill rod 1 are assembled in place, an integral drill bit structure is formed.

[0021] The obtuse-angled positioning surfaces 22 on both sides of the crown cutter head 2 are symmetrical structures, and the angle of the obtuse-angled positioning surfaces 22 is specifically 120° to 150°.

[0022] During specific implementation, the front end thread 31 of the tightening screw 3 is specifically a right-handed thread, and the rear end thread 32 is specifically a left-handed thread.

[0023] The cross section of the spiral chip removal groove 14 is a U-shaped groove structure, and a protective blade edge 18 is arranged in the spiral chip removal groove 14. The groove body structure of the U-shaped groove makes the chip space large and the chip removal smooth. At the same time, the strength of the knife back is high, and the feed speed is fast during processing. The protective blade edge 18 reduces the groove front angle of the outer diameter part to prevent the drill rod from participating in the cutting under harsh working conditions and causing the knife to break;

[0024] Two bypass pipes 5 are arranged on the outer periphery of the front end of the main cooling hole 4 facing the working part 11, forming a Y-shaped passage outlet, and the Y-shaped passage outlet is connected to the liquid outlet 6 through the branch 8, and the coolant is provided to the crown cutter head 2 during operation. The coolant of the main cooling hole 4 is sprayed out from the liquid outlet on the front end surface through two transfers, and directly sprayed to the cutting edge of the crown cutter head 2. ;

[0025] The handle 13 of the drill rod 1 has a 2° inclined side pressure surface 19, which is locked by the side pressure locking screw of the tool handle. When in use, the tool handle clamps the handle to transmit the machine tool power, so that the tool rotates and has cutting ability;

[0026] The neck 12 is a combination of a cone and a cylinder, which can prevent chips from splashing and hitting the tool handle and the machine tool spindle during operation, thus playing a protective role.

[0027] Its working principle is as follows: the locking threaded hole of the crown cutter head is connected to at least a part of the front end thread of the tightening screw. During pre-installation, a certain amount of installation clearance for the front end thread is left, and then the crown cutter head is positioned in the crown cutter head positioning cavity, and the rear end thread of the tightening screw is connected to the concave center threaded hole. The hexagonal wrench penetrates the main cooling hole and then the tightening screw is tightened, so that the rear end thread of the tightening screw is connected to the concave center threaded hole, and at the same time, the rear end face of the crown cutter head and the end stop surface of the crown cutter head positioning cavity are arranged in close contact with each other to complete the tightening and locking. The crown drill bit is locked through the rear-pull structure and the drill rod, so that the locking is stable and reliable. In addition, the coolant is connected to the liquid outlet and the liquid outlet gap through the main cooling hole, so that the coolant directly cools the cutting edge of the crown drill bit, and the cooling effect is good.

[0028] The rear-pull crown drill bit adopts the center rear-pull locking, which has large tensioning force, reliable installation, and will not loosen during processing; the center rear-pull locking screw adopts the left-handed design, which is easy to install and will not loosen during processing; the left-handed tightening thread in the center of the drill rod has high precision in cooperation with the locking screw, which effectively prevents leakage of the coolant in the center, thereby affecting the cooling effect; the positioning surfaces on both sides of the drill rod adopt an obtuse angle design, and the angle of 100°~154° helps to have a large supporting area of ​​the drill rod and high supporting strength; the drill rod material uses high-strength alloy steel, which has high strength, good wear resistance, good shock resistance and long service life.

[0029] Its beneficial effects are as follows: based on the Y-type internal cooling structure, the coolant directly cools the cutting edge, which has a good cooling effect on the heat generated during processing; at the same time, due to the different diameters of the cooling holes, the cooling pressure will be further increased by flowing in from the large diameter and out from the small diameter; the chip removal groove adopts a U-shaped design, the tool rod has good rigidity, can withstand large feed processing, and is not easy to break. The U-shaped groove has a protective knife edge design, which effectively prevents the front cutting face of the drill rod from participating in cutting and extrusion, causing the drill rod to break; the front end of the drill rod has a supporting surface, which plays an effective supporting role during drilling processing and makes drilling smooth; the drill rod shank has a 2° inclined side pressure surface, which can prevent the drill bit from loosening due to axial displacement during processing after installation and locking.

[0030] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0031] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A new type of cooling back-pull crown drill, characterized by: It includes a drill rod and a toothed crown cutter head. The drill rod includes a working part, a neck and a handle. The outer periphery of the working part of the drill rod is provided with a spiral chip removal groove and a blade back. The front end center position of the working part is concave to form a toothed crown cutter head positioning cavity. The toothed crown cutter head is embedded in the toothed crown cutter head positioning cavity. The toothed crown cutter head includes a locking threaded hole concave at the rear end. The locking threaded hole of the toothed crown cutter head is connected to the front end thread of the tightening screw. The axial inner end of the toothed crown cutter head positioning cavity of the working part is provided with a concave center threaded hole. The rear end thread of the tightening screw is connected to the concave center threaded hole. The front end thread of the tightening screw and the rear end thread The end threads have opposite rotation directions, a main cooling hole is provided at the axial center position of the drill rod, the inner concave center threaded hole is connected to the main cooling hole, at least two bypass pipelines are provided at the front end periphery of the main cooling hole facing the working part, two liquid outlets are provided at the position of the end stop surface of the main cooling hole facing the positioning cavity of the crown cutter head, a liquid outlet notch is provided at the position corresponding to the liquid outlet, the rear end face of the crown cutter head in the assembled state and the end stop surface plane of the positioning cavity of the crown cutter head are arranged in close contact; the crown cutter head and the working part of the drill rod are assembled in place to form an integral drill bit structure; Two bypass pipelines are arranged on the outer periphery of the front end of the main cooling hole facing the working part to form a Y-shaped passage outlet, and the Y-shaped passage outlet is connected to the liquid outlet through a branch respectively; The obtuse-angled positioning surfaces on both sides of the tooth crown cutter head are symmetrical structures.

2. A new type of cooling back-pull crown drill bit as claimed in claim 1, characterized in that: The cross section of the spiral chip removal groove is a U-shaped groove structure, and a protective blade edge is arranged in the spiral chip removal groove.

3. A new type of cooling back-pull crown drill bit as claimed in claim 1, characterized in that: The handle of the drill rod is provided with a side pressure surface inclined at 2°.

4. A new type of cooling back-pull crown drill bit as claimed in claim 1, characterized in that: The neck is a combination of a cone and a cylinder.

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