High-strength detachable screw locking replaceable tip drill bit

Abstract

The application discloses a high-strength and easy-to-disassemble screw locking replaceable drill tip type drill bit, and belongs to the technical field of cutting tools. The drill bit comprises a cutter body, the cutter body comprises a shank, and a clamping groove is arranged on a working portion of the shank to fix a drill tip. The clamping groove is provided with a clamping groove locking surface, and the clamping groove locking surface is provided with a threaded hole. The drill tip comprises a drill tip locking surface, the drill tip is installed into the clamping groove along a central axis of the cutter body, a clamping screw penetrates into the threaded hole, a front end of the clamping screw abuts against the drill tip locking surface, and an axis of the threaded hole is offset from the central axis of the cutter body by an offset amount m so as to exert a torque action of the drill tip around the central axis of the cutter body. The axis of the threaded hole of the drill bit is offset from the central axis of the cutter body, the clamping groove generates a limiting action on the drill tip when the drill tip is assembled to the cutter body, the offset clamping screw exerts a locking torque of the drill tip around the central axis of the cutter body, and the fixation of the drill tip and the cutter body is realized.

Description

Technical Field

[0001] This invention belongs to the field of cutting tool technology, specifically relating to a high-strength, easily detachable, screw-locking, replaceable drill tip type drill bit. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Drilling tools can be divided into solid drill bits and replaceable drill bits. During use, drill bits require frequent sharpening of the cutting edge to ensure machining quality. After replacing a solid drill bit, operations such as repositioning on the machine tool are required, which takes a long time and results in a production efficiency far lower than that of replaceable drill bits.

[0004] The structure of a replaceable drill bit mainly consists of the cutter body and the drill tip. Existing drill bit body and tip fixing structures can be divided into self-locking structures and screw-locking structures. Self-locking drill bits rely on an interference fit to fix the cutter body and drill tip. However, because fatigue or wear failure of the interference part under high-frequency use cannot be avoided, its service life is actually shorter than that of screw-locking drill bits. Existing screw-locking drill bits are complex to assemble and disassemble, and require the drill tip to have complex fitting structures such as through holes, tie rods, interference surfaces, or other complex fits, making drill tip manufacturing difficult and weakening the drill tip's strength. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-strength, easily detachable, screw-locked, replaceable drill tip. The axis of the threaded hole in this drill tip is offset from the central axis of the tool body. When the drill tip is assembled onto the tool body, the clamping groove limits the drill tip, and the offset set screw applies a locking torque around the central axis of the tool to the drill tip, thereby fixing the drill tip to the tool body. This invention has advantages such as high structural strength, precise positioning, easy manufacturing, and quick assembly and disassembly.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] In a first aspect, the present invention provides a high-strength, easily detachable, screw-lockable, replaceable drill bit, comprising a cutter body, the cutter body including a shank, the shank working portion being provided with a clamping groove to fix the drill tip; the clamping groove having a clamping groove locking surface, the clamping groove locking surface having a threaded hole, the drill tip including a drill tip locking surface, the drill tip being installed in the clamping groove along the central axis of the cutter body, a set screw passing through the threaded hole, the front end of the set screw abutting against the drill tip locking surface, and the axis of the threaded hole having an offset of m from the central axis of the cutter body to apply a torque around the central axis of the cutter body to the drill tip.

[0008] As a further technical solution, the clamping groove locking surface is fitted with the drill tip locking surface to achieve circumferential positioning of the drill tip relative to the tool body around the central axis of the tool body; the structure of the tool body and the drill tip is symmetrical about the central axis of the tool body.

[0009] As a further technical solution, the clamping groove locking surface includes a clamping groove force transmission part and a clamping groove locking part connected to each other, and the drill tip locking surface includes a drill tip force transmission part and a drill tip locking part connected to each other. The clamping groove force transmission part and the drill tip force transmission part are fitted together to transmit the torque between the tool body and the drill tip during drilling.

[0010] As a further technical solution, the clamping groove also includes a clamping groove bottom surface, a clamping groove locking surface is disposed on both sides of the clamping groove bottom surface, and a clamping groove positioning surface is disposed on the side of the clamping groove locking surface; the clamping groove positioning surface is an inclined surface with an angle to the clamping groove bottom surface.

[0011] As a further technical solution, the drill tip also includes a bottom surface of the drill tip connected to the drill tip locking surface, the drill tip locking surface being connected to the drill tip positioning surface, and the clamping groove positioning surface fitting with the drill tip positioning surface to achieve centering constraint and axial positioning of the drill tip.

[0012] As a further technical solution, the drill tip positioning surface is an inclined surface with an angle to the bottom surface of the drill tip; the drill tip locking surface is connected to the chip guide groove surface, and the top of the drill tip is provided with a cutting surface, which is connected to the drill tip locking surface.

[0013] As a further technical solution, the outer diameter of the working part of the tool body is d1, the offset m between the axis of the threaded hole and the central axis of the tool body is in the range of (0~0.5)d1; the fitting clearance s1 between the clamping groove locking surface and the drill tip locking surface is -0.1mm~0.1mm.

[0014] As a further technical solution, the outer diameter of the working part of the cutter body is d1, the fitting clearance between the bottom surface of the clamping groove and the bottom surface of the drill tip is s2 = (0-0.1)d1; the included angle between the positioning surface of the clamping groove and the bottom surface of the clamping groove is equal to the included angle between the positioning surface of the drill tip and the bottom surface of the drill tip, which is α, and the value of α is in the range of 90°<α<180° or 180°<α<270°; the thickness of the drill tip is 0.05 to 0.8 times d1.

[0015] As a further technical solution, a groove is provided at the contact position between the drill tip and the set screw; the drill tip is fixed to the cutter body by a plurality of set screws.

[0016] As a further technical solution, the clamping groove locking surface and the drill tip locking surface are single-segment planes, multiple-segment planes, or curved surfaces.

[0017] The beneficial effects of the present invention are as follows:

[0018] Compared to existing replaceable drill bits, the drill bit of this invention uses the offset between the axis of the threaded hole and the central axis of the tool to provide locking torque to the drill tip with the set screw, which presses the mating surface between the tool body and the drill tip, resulting in high strength and thus generating frictional force to prevent the drill tip from falling off. The structure has a long service life and reliable connection.

[0019] Compared to existing replaceable drill bits, the drill bit of this invention only requires the drill tip and the cutter body to be connected by a set screw. While having a long service life, it eliminates the need to design through holes, tie rods, interference surfaces and other complex mating structures in the drill tip, thus avoiding weakening the strength of the drill tip. The drill tip structure is simple, has higher strength, is easy to process and inspect, and reduces the production cost of matching drill tips.

[0020] Compared to the steps involved in installing and removing drill tips in existing replaceable drill bits, this invention allows for installation and removal of drill tips simply by loosening the set screw, without dislodging the screw from the threaded hole, thus significantly reducing installation and removal time. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 This is an assembly diagram of the screw-locking replaceable drill tip type drill bit of the present invention;

[0023] Figure 2 This is a right view of the blade body of the present invention;

[0024] Figure 3 This is a perspective view of the blade body of the present invention;

[0025] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0026] Figure 5 This is a partial cross-sectional view of the blade clamping groove of the present invention;

[0027] Figure 6 This is a perspective view of the drill tip of the present invention;

[0028] Figure 7 This is a front view of the drill tip of the present invention;

[0029] Figure 8 This is a partial view of the drill tip position after the drill bit of the present invention is assembled;

[0030] Figure 9 for Figure 8 Sectional view along the AA direction;

[0031] Figure 10 This is a perspective view of the first improved drill tip of the present invention;

[0032] Figure 11 This is a cross-sectional view of the screw mating joint of the second improved version of the present invention;

[0033] Figure 12 This is a perspective view of the third improved blade of the present invention;

[0034] In the diagram: the spacing or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only.

[0035] The components are as follows: 1. Tool body; 2. Drill tip; 3. Set screw; 11. Shank; 12. Clamping groove; 121. Threaded hole; 122. Clamping groove locking surface; 123. Clamping groove positioning surface; 124. Clamping groove bottom surface; 122a. Clamping groove force transmission part; 122b. Clamping groove locking part; 21. Cutting surface; 22. Drill tip locking surface; 23. Drill tip positioning surface; 24. Drill tip bottom surface; 25. Chip guide groove surface; 26. Shallow groove; 22a. Drill tip force transmission part; 22b. Drill tip locking part. Detailed Implementation

[0036] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] In a typical embodiment of the present invention, such as Figure 1 As shown, a high-strength, easily detachable, screw-locked, replaceable drill bit is proposed, comprising a cutter body 1, a drill tip 2, and a set screw 3. The structures of the cutter body and drill tip are symmetrical about the central axis of the cutter body.

[0038] like Figure 2 As shown, the blade body 1 includes a handle 11 and a clamping groove 12. The clamping groove 12 is disposed at the working end of the handle 11 and is used to fix the blade tip 2. Wherein, as Figures 3-5 As shown, the clamping groove 12 includes a threaded hole 121, a clamping groove locking surface 122, a clamping groove positioning surface 123, and a clamping groove bottom surface 124. The threaded hole 121 is provided on the clamping groove locking surface 122 for passing through a set screw 3 to fasten the drill tip 2 and the tool body 1. The clamping groove locking surfaces 122 are provided on both sides of the clamping groove bottom surface 124 to form a C-shaped groove. The clamping groove positioning surface 123 is provided in the C-shaped groove corresponding to the side of the clamping groove locking surface 122. The clamping groove locking surface 122 is divided into a clamping groove force transmission part 122a and a clamping groove locking part 122b by the projection of the tool body central axis on it. The clamping groove force transmission part 122a and the clamping groove locking part 122b are connected.

[0039] like Figures 6-7As shown, the drill tip 2 includes a cutting surface 21, a chip guide groove surface 25, a drill tip positioning surface 23, a drill tip locking surface 22, and a drill tip bottom surface 24. The chip guide groove surface 25, the drill tip locking surface 22, and the drill tip positioning surface 23 are connected in sequence, and the chip guide groove surface 25, the drill tip locking surface 22, and the drill tip positioning surface 23 are all connected to the drill tip bottom surface 24. The cutting surface 21 is located at the top of the drill tip and is connected to the drill tip locking surface 22.

[0040] In a preferred embodiment, the drill tip positioning surface 23 is an inclined surface that forms an angle with the drill tip bottom surface 24. For example... Figure 7 As shown, corresponding to the cutter body, the drill tip locking surface 22 is also divided into a drill tip force transmission part 22a and a drill tip locking part 22b, with the projection of the cutter body's central axis onto it as the boundary.

[0041] When the drill tip 2 is assembled onto the tool body 1, the drill tip 2 is installed in the clamping groove 12 along the central axis of the tool body. The clamping groove locking surface 122 and the drill tip locking surface 22 fit together to achieve circumferential positioning of the drill tip 2 relative to the tool body 1 around the central axis of the tool body. The clamping groove force transmission part 122a fits together with the drill tip force transmission part 22a to transmit the torque between the tool body 1 and the drill tip 2 during drilling. The clamping groove positioning surface 123 and the drill tip positioning surface 23 fit together to achieve centering constraint and axial positioning of the drill tip 2.

[0042] Set screw 3 is installed into threaded hole 121, with its front end abutting against drill tip locking surface 22. (Example:) Figure 9 As shown, the axis of the threaded hole 121 is offset by a distance m from the central axis of the tool body. After the set screw 3 is tightened, a torque is applied to the drill tip 2 around the central axis of the tool body. Under the action of torque, the drill tip locking part 22b and the clamping groove locking part 122b are pressed together. The pressing surfaces provide friction to prevent the drill tip 2 from falling off, thus achieving complete fixation of the tool body 1 and the drill tip 2.

[0043] When installing or removing the drill tip 2, loosen the set screw 3 to remove the locking force between the cutter body 1 and the drill tip 2, and then remove the drill tip 2 along the axial direction of the cutter body 1.

[0044] The outer diameter of the working part of the tool body is d1. The clamping groove 12 is provided in the working part of the tool body, and the drill tip is fixed in the working part of the tool body. In order to ensure that there is sufficient locking force between the tool body 1 and the drill tip 2, the offset m between the axis of the threaded hole 121 and the central axis of the tool body is in the range of (0~0.5)d1.

[0045] The fitting clearance s1 between the clamping groove locking surface 122 and the drill tip locking surface 22 can provide temporary locking force for the tool body 1 and the drill tip 2 before the set screw 3 is screwed in to assist assembly. The value of s1 should be controlled between -0.1mm and 0.1mm.

[0046] To simultaneously achieve centering constraint and axial limiting, the clamping groove positioning surface 123 is also an inclined surface with an angle to the bottom surface 124 of the clamping groove. During assembly, the clamping groove positioning surface 123 and the drill tip positioning surface 23 fit together, such as... Figure 5 As shown, the angle α between the clamping groove positioning surface 123 and the clamping groove bottom surface 124 ranges from 90° < α < 180° to 180° < α < 270°. Correspondingly, the angle between the drill tip positioning surface 23 and the drill tip bottom surface 24 is also α, and its range is also 90° < α < 180° to 180° or 180° < α < 270°.

[0047] To avoid over-constraint, the fit clearance between the bottom surface 124 of the clamping groove and the bottom surface 24 of the drill tip is s2 = (0-0.1)d1.

[0048] The drill tip locking surface 22 and its corresponding clamping groove locking surface 122 are preferably single-section planes, so that the drill tip force transmission part 22a and the drill tip locking part 22b are coplanar, and the clamping groove force transmission part 122a and the clamping groove locking part 122b are coplanar, which is easy to manufacture.

[0049] To ensure the strength of the clamping groove locking part 122b and the drill tip locking part 22b, the drill tip thickness t1 is preferably 0.05 to 0.8 times the outer diameter d1 of the working part of the tool.

[0050] Compared to existing replaceable drill bits, the tool body clamping groove of this invention is formed in one piece and does not require re-grinding, thus improving production efficiency and saving resources.

[0051] As the first optimization scheme, such as Figure 10 As shown, the contact position between the drill tip 2 and the set screw 3 may have a shallow groove 26 to enhance the locking effect.

[0052] As a second optimization, the threaded holes 121 can be arranged symmetrically about the tool's central axis, with multiple set screws 3 used to fix the drill tip 2, to accommodate the installation requirements of large-diameter or multi-flute drill bits, such as... Figure 11 This is a multi-set screw structure in a two-flute drill bit.

[0053] As a third optimization scheme, such as Figure 12 As shown, the clamping groove locking surface 122 and its corresponding drill tip locking surface 22 can be multiple flat or curved surfaces to adapt to the cutting edge design requirements.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-strength, easily detachable, screw-locking, replaceable drill bit, characterized in that, The tool includes a cutting body, which includes a shank. The working part of the shank is provided with a clamping groove to fix the drill tip. The clamping groove is provided with a clamping groove locking surface and a threaded hole. The drill tip includes a drill tip locking surface. The drill tip is installed in the clamping groove along the central axis of the tool body. A set screw passes through the threaded hole, and the front end of the set screw abuts against the drill tip locking surface. The axis of the threaded hole is offset from the central axis of the tool body by a distance m to apply a torque around the central axis of the tool body to the drill tip. The outer diameter of the working part of the cutter body is d1, and the offset m between the axis of the threaded hole and the central axis of the cutter body is in the range of (0~0.5)d1; the fit clearance s1 between the clamping groove locking surface and the drill tip locking surface is -0.1mm~0.1mm; The clamping groove locking surface includes a clamping groove force transmission part and a clamping groove locking part connected to each other. The drill tip locking surface includes a drill tip force transmission part and a drill tip locking part connected to each other. The clamping groove force transmission part and the drill tip force transmission part are in contact to transmit the torque between the tool body and the drill tip during drilling. The clamping groove also includes a clamping groove bottom surface. The clamping groove locking surface is disposed on both sides of the clamping groove bottom surface. A clamping groove positioning surface is disposed on the side of the clamping groove locking surface. The clamping groove positioning surface is an inclined surface with an angle to the clamping groove bottom surface.

2. The high-strength, easily detachable, screw-locking, replaceable drill bit as described in claim 1, characterized in that, The clamping groove locking surface fits into the drill tip locking surface to achieve circumferential positioning of the drill tip relative to the tool body around the central axis of the tool body; the structures of the tool body and the drill tip are symmetrical about the central axis of the tool body.

3. The high-strength, easily detachable, screw-locking, replaceable drill bit as described in claim 1, characterized in that... The drill tip also includes a bottom surface of the drill tip connected to the locking surface of the drill tip. The locking surface of the drill tip is connected to the positioning surface of the drill tip. The positioning surface of the clamping groove is fitted to the positioning surface of the drill tip to achieve centering constraint and axial positioning of the drill tip.

4. The high-strength, easily detachable, screw-locking, replaceable drill bit as described in claim 3, characterized in that... The drill tip positioning surface is an inclined surface with an angle to the bottom surface of the drill tip; the drill tip locking surface is connected to the chip guide groove surface, and the top of the drill tip is provided with a cutting surface, which is connected to the drill tip locking surface.

5. The high-strength, easily detachable, screw-locking, replaceable drill bit as described in claim 4, characterized in that... The outer diameter of the working part of the cutter body is d1, and the fitting clearance between the bottom surface of the clamping groove and the bottom surface of the drill tip is s2=(0-0.1)d1; the included angle between the positioning surface of the clamping groove and the bottom surface of the clamping groove is the included angle between the positioning surface of the drill tip and the bottom surface of the drill tip, which is α, and the value of α is in the range of 90︒<α<180︒ or 180︒<α<270︒; the thickness of the drill tip t1 is 0.05~0.8 times d1.

6. The high-strength, easily detachable, screw-locking, replaceable drill bit as described in claim 1, characterized in that... The drill tip has a groove at the contact position with the set screw; the drill tip is fixed to the cutter body by multiple set screws.

7. The high-strength, easily detachable, screw-locking, replaceable drill bit as described in claim 1, characterized in that... The clamping groove locking surface and the drill tip locking surface are single-segment planes, multiple-segment planes, or curved surfaces.

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