Long-life high-efficiency drill bit

Abstract

The utility model discloses a long -life high -efficient drill bit, including handle, still include work part, work part is coaxial with handle, work part includes two main relief, two main relief is opposite with the center axle of work part as the pivot, and the intersection of two main relief forms the chisel edge, and the rake angle gamma of chisel edge place is =-42~-50 DEG, and the length of chisel edge is that the diameter of work part outer circle is =0.2:6 ~ 0.6:16. The utility model aims at providing a long -life high -efficient drill bit, and the utility model aims at providing a kind of drill bit with good centering, long service life, and not easy to break blade.

Description

Technical Field

[0001] This utility model relates to the field of metal cutting and machining, and in particular to a long-life, high-efficiency drill bit. Background Technology

[0002] A drill bit is one of the most commonly used cutting tools in machining. It rotates at high speed to drill holes in the workpiece. For machining, the performance of the drill bit directly affects machining efficiency, tool life, and production costs for the company.

[0003] The working part of a drill bit typically consists of five cutting edges and six facets. These include the rake face, the primary flank face, the secondary flank face, the primary cutting edge, the secondary cutting edge, and the chisel edge. The rake face is the helical chip groove near the primary cutting edge, which serves to form the cutting edge, expel cutting material, and allow cutting fluid to pass through. The primary flank face is the surface on the drill tip formed by the primary cutting edge, the chip flank, another chip groove, and the chisel edge. The primary cutting edge is the cutting edge formed by the intersection of the rake face and the primary flank face. The chisel edge is the cutting edge formed by the connecting line of the two primary cutting edges, which is the intersection of the two primary flank faces.

[0004] When designing a drill bit, the auxiliary planes required include the base plane, the cutting plane, and the orthogonal plane. The base plane is the plane passing through a selected point on the main cutting edge and containing the drill axis. The cutting plane is the plane formed by the line containing the cutting velocity vector at any point on the main cutting edge and the drill bit itself. The orthogonal plane is the plane passing through any point on the main cutting edge and perpendicular to both the base plane and the cutting plane. Additionally, when designing a drill bit, parameters that need to be designed include the rake angle, which is the angle between the rake face and the base plane within the principal orthogonal plane.

[0005] With technological advancements, existing drill bits, building upon traditional forming techniques, typically incorporate a re-grinding process for the chisel edge to enhance performance. However, this process presents several challenges: 1. Due to the zero linear velocity of the chisel edge during cutting, it experiences significant compressive force. Shorter chisels facilitate cutting, resulting in better centering capabilities. However, they are also prone to wear and chipping. Longer chisels, while strengthening them, reduce cutting ability, leading to poor centering and increased heat generation during cutting. Inadequate heat dissipation can cause overheating and reduced drill bit strength. Summary of the Invention

[0006] Purpose of the utility model: The purpose of this utility model is to provide a long-life, high-efficiency drill bit. This utility model aims to provide a drill bit with good centering, long service life, and less prone to chipping.

[0007] Technical solution: The present invention discloses a long-life, high-efficiency drill bit, comprising a shank and a working part, wherein the working part is coaxial with the shank and includes two main flank faces, which are arranged opposite each other with the central axis of the working part as the axis. The two main flank faces intersect to form a chisel edge, and the rake angle γ at the chisel edge is -42° to -50°. The length of the chisel edge to the diameter of the outer circle of the working part is 0.2:6 to 0.6:16.

[0008] Furthermore, the rake angle γ at the transverse blade is -46.5°, and the length of the transverse blade is 0.28 times the diameter of the outer circle of the working part.

[0009] Furthermore, the main flank face includes a main cutting edge for cutting the workpiece, and the projection of the main cutting edge in a projection plane perpendicular to the drill bit's central axis is a convex curved shape. This convex curved shape means that the cutting edge line of the main cutting edge protrudes in the cutting direction; alternatively, it means that the center of the main cutting edge is not in the cutting direction, but in the opposite direction. The convex projection of the main cutting edge in a projection plane perpendicular to the drill bit's central axis has the advantage of preventing chipping at the ends of the main cutting edge compared to existing technologies. Specifically, in existing drill bits, the main cutting edge is concave in a projection plane perpendicular to the drill bit's central axis, making it easier for stress to concentrate at both ends of the main cutting edge during cutting. The impact at the ends of the main cutting edge is greater than that at other parts of the main cutting edge, thus making it more prone to chipping.

[0010] Furthermore, the projected curve of the main cutting edge in a projection plane perpendicular to the drill bit's central axis is an arc shape.

[0011] Furthermore, the main cutting edge includes a connecting cutting edge connected to the chisel edge. The projection of the connecting cutting edge in a projection plane perpendicular to the drill bit's central axis is a polygonal line, and the cutting edge line of the connecting cutting edge also convexes in the cutting direction. That is, viewed from the projection plane perpendicular to the drill bit's central axis, the connecting cutting edge is composed of several straight lines connected end to end at different angles, and the cutting edge line of the connecting cutting edge also convexes in the cutting direction. The advantage of the polygonal shape of the connecting cutting edge is to prevent chipping of the main cutting edge. Specifically, firstly, the connecting cutting edges at different angles can prevent stress concentration during cutting; secondly, the cutting feed rate of the connecting cutting edges at different angles is gradual, which can reduce the impact of the workpiece on the main cutting edge.

[0012] Furthermore, each of the main flank faces is provided with several chip-breaking steps, the height of which decreases sequentially along the chisel edge towards the outer edge of the main flank face. The purpose of these chip-breaking steps is to utilize their edges for chip breaking, preventing the generation of long iron chips during drill bit operation. These iron chips are typically spiral or sheet-like, and due to their length, they are difficult to expel from the chip groove. This not only hinders heat dissipation, potentially causing the main cutting edge to weaken due to excessive temperature, reducing drill bit lifespan, but also increases the cutting thickness of the main cutting edge, leading to chipping and increasing production costs for the enterprise. In existing technologies, some drill bits also have chip flutes. However, the chip-breaking step in this invention differs from the chip flute for the following reasons: 1. Although the chip flute also has the function of chip breaking, its depth is not very deep. Therefore, the chip flute cannot break long iron chips. Due to the limited depth of the chip flute, the stress during chip breaking is also prone to concentrate on both sides of the chip flute. The chip-breaking step in this invention does not have the chip flute problem; 2. The chip-breaking step in this invention can increase the space between the tool and the workpiece, which is beneficial for heat dissipation and improving chip removal efficiency.

[0013] Furthermore, adjacent step breaks are connected by a connecting arc surface. The projection of this connecting arc surface onto the projection plane passing through the drill bit's central axis is arc-shaped. This design prevents stress concentration at the edges of the step breaks, thereby preventing edge chipping.

[0014] Furthermore, the projection of each main cutting edge in the projection plane passing through the drill bit's central axis includes several main cutting sub-edges (these several main cutting sub-edges may be formed due to the setting of a dividing step, or they may be formed due to other reasons, such as setting several protrusions on the main flank face). The outermost main cutting sub-edge is the first main cutting sub-edge, and the included angle between the two symmetrical first main cutting sub-edges is 145° to 155°.

[0015] A long-life, high-efficiency drill bit includes a shank and a working part. The working part is coaxial with the shank and includes two main flank faces. Each main flank face is provided with several cutting steps. The height of the several cutting steps decreases sequentially along the chisel edge towards the outer edge of the main flank face.

[0016] Furthermore, adjacent steps are connected by a connecting arc surface. The projection of the connecting arc surface onto the projection plane passing through the drill bit's central axis is arc-shaped.

[0017] Beneficial effects: Compared with the prior art, this utility model has the following advantages: 1. Because the rake angle of the chisel edge in this utility model is greater than that of the chisel edge in existing drill bits, this utility model has better cutting ability than existing drill bits, which also makes this utility model have better centering ability. Furthermore, because the chisel edge of this utility model has better centering ability, this utility model can strengthen the strength of the chisel edge by increasing its length. Therefore, this utility model can balance centering ability and chisel edge strength. 2. Because the projection of the main cutting edge of this utility model in the projection plane perpendicular to the center axis of the drill bit is a convex curve shape, the stress generated during cutting is not concentrated at the two ends, which prevents the two ends of the main cutting edge, especially the outer end, from chipping and extends the service life of the tool. 3. The projection of the cutting connecting edge connected to the chisel edge in the projection plane perpendicular to the drill bit's central axis is a broken line, which can reduce the impact on the main cutting edge during cutting, prevent the main cutting edge from chipping, especially prevent the main cutting edge near the chisel edge from chipping, and extend the tool's service life. 4. This utility model is equipped with several chip-breaking steps, which not only prevents the generation of long iron chips, but also facilitates heat dissipation and extends the service life of the tool. Attached Figure Description

[0018] Figure 1 This is a side view of a planar drill bit in the prior art.

[0019] Figure 2 This is a top view of a planar drill bit in the prior art.

[0020] Figure 3 This is a side view of a conventional arc-shaped drill bit.

[0021] Figure 4 This is a top view of an existing curved drill bit.

[0022] Figure 5 This is a perspective view of the present invention.

[0023] Figure 6 This is a side view of the present invention.

[0024] Figure 7 for Figure 6 Enlarged view at point A.

[0025] Figure 8 This is a top view of the present invention.

[0026] Figure 9 for Figure 8 Enlarged view at point B.

[0027] Figure 10 This is a schematic diagram of the rake angle of the transverse blade in this utility model.

[0028] Wherein: 1. Tool holder; 2. Working part of existing flat drill bit; 201. Rake face of existing flat drill bit; 202. Main cutting edge of existing flat drill bit; 203. Main flank face of existing flat drill bit; 3. Working part of existing curved drill bit; 301. Rake face of existing curved drill bit; 302. Main cutting edge of existing curved drill bit; 303. Main flank face of existing curved drill bit; 4. Working part; 401. Rake face; 402. Main cutting edge; 4021. First main cutting edge; 4022. Second main cutting edge; 403. Main flank face; 404. Chisel edge; 405. Dividing step. Detailed Implementation

[0029] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0030] Appendix Figures 1-2 The image shows an existing flat drill bit, made from... Figure 1 and Figure 2 It can be seen that the main flank face 203 and the rake face 201 of the existing flat drill bit intersect to form the main cutting edge 202 of the existing flat drill bit. The main cutting edge 202 of the existing flat drill bit, when projected onto the plane passing through the drill bit's central axis, appears as a straight line, similar to a side view. However, when projected onto the plane perpendicular to the drill bit's central axis, the main cutting edge 202 of the existing flat drill bit appears as a concave shape, similar to a top view. The so-called concave shape means that in the cutting direction, the main cutting edge 202 of the existing flat drill bit is concave relative to the line connecting its two ends. It can also be said that the center of the main cutting edge 202 of the existing flat drill bit is located in its cutting direction, and the projection is concave. This makes it easier for the stress of the existing flat drill bit to concentrate at both ends of the main cutting edge 202 during the cutting process. The impact it receives is greater than that of other parts, and therefore it is more prone to chipping.

[0031] Appendix Figures 3-4 The image shows an existing arc-shaped drill bit, made from... Figure 3 and Figure 4It can be seen that the main flank face 303 and the rake face of the existing arc-shaped drill bit intersect to form the main cutting edge 302 of the existing arc-shaped drill bit. The main cutting edge 302 of the existing arc-shaped drill bit has an arc-shaped projection similar to a side view projection within the projection arc surface passing through the drill bit's central axis. Compared with the existing flat drill bit, the space between the main flank face 203 and the workpiece of the existing flat drill bit is larger, making chip removal easier. However, similar to the existing flat drill bit, the main cutting edge 302 of the existing arc-shaped drill bit has a concave shape in the projection arc surface perpendicular to the drill bit's central axis, similar to a top view projection. The so-called concave shape means that in the cutting direction, the main cutting edge 302 of the existing arc-shaped drill bit is concave relative to the line connecting its two ends. It can also be said that the center of the main cutting edge 302 of the existing arc-shaped drill bit is located in its cutting direction, and the projection is concave. This makes the stress of the existing arc-shaped drill bit more likely to concentrate at both ends of the main cutting edge 302 during the cutting process. The impact it receives is greater than that of other parts, and therefore it is more prone to chipping.

[0032] Therefore, whether it is an existing flat drill bit or an existing curved drill bit, the rake angle of its main cutting edge is between -54° and -60°, so it is difficult for its chisel edge to balance centering and strength.

[0033] See appendix Figures 5-10 The present invention discloses a long-life, high-efficiency drill bit, including a shank 1 and a working part 4. The working part 4 is coaxial with the shank 1 and includes two main flank faces 403. The two main flank faces 403 are arranged opposite each other with the central axis of the working part 4 as the axis. The two main flank faces 403 intersect to form a chisel edge 404. The rake angle γ at the chisel edge 404 is -42° to -50°. The length of the chisel edge 404 to the diameter of the outer circle of the working part 4 is 0.2:6 to 0.6:16.

[0034] Optionally, the rake angle γ at the transverse blade 404 is -46.5°, and the length of the transverse blade 404 is 0.28:8 of the diameter of the outer circle of the working part 4.

[0035] Optionally, the main relief face 403 includes a main cutting edge 402 for cutting the workpiece. The projection of the main cutting edge 402 in a projection plane perpendicular to the drill bit's central axis is a convex curved shape. The convex curved shape means that the cutting edge of the main cutting edge 402 protrudes in the cutting direction; alternatively, it means that the center of the main cutting edge 402 is not in the cutting direction, but in the opposite direction. The convex projection of the main cutting edge 402 in a projection plane perpendicular to the drill bit's central axis has the advantage of preventing chipping at the ends of the main cutting edge 402 compared to existing technologies.

[0036] Optionally, the projected curve of the main cutting edge 402 in a projection plane perpendicular to the drill bit's central axis is an arc shape. In other embodiments, the projected curve of the main cutting edge 402 in a projection plane perpendicular to the drill bit's central axis can be composed of multiple straight lines, multiple arcs, or a combination of straight lines and arcs.

[0037] Optionally, the main cutting edge 402 includes a connecting cutting edge connected to the chisel edge 404. The projection of the connecting cutting edge in a projection plane perpendicular to the drill bit's central axis is a polygonal line, and the cutting edge line of the connecting cutting edge also protrudes in the cutting direction. In other embodiments, the connecting cutting edge may also be composed of one or more arcs of different curvatures connected end to end.

[0038] Optionally, each main flank face 403 is provided with several dividing steps 405, and the height of the several dividing steps 405 decreases sequentially along the transverse cutting edge 404 toward the outer edge of the main flank face 403.

[0039] Optionally, two adjacent segmented steps 405 are connected by a connecting arc surface. In other embodiments, two adjacent segmented steps 405 can also be connected by a straight slope, as long as the angle between the connecting surface of two adjacent segmented steps 405 and the top surface of the segmented step 405 is greater than 90°. This is because an angle ≤90° between the connecting surface of two adjacent segmented steps 405 and the top surface of the segmented step 405 will cause the edge of the segmented step to chip due to stress concentration.

[0040] Optionally, the projection of each main cutting edge 402 in the projection plane passing through the drill bit's central axis includes a first main cutting edge 4021 and a second main cutting edge 4022, with the first main cutting edge 4021 located on the outermost side and the included angle between the two symmetrical first main cutting edges 4021 being 150°.

Claims

1. A long-life, high-efficiency drill bit, comprising a tool holder (1) and a working part (4), wherein the working part (4) is coaxial with the tool holder (1), characterized in that: The working part (4) includes two main flank faces (403). The two main flank faces (403) are arranged opposite each other with the central axis of the working part (4) as the axis. The two main flank faces (403) intersect to form a chisel edge (404). The rake angle γ at the chisel edge (404) is -42° to -50°. The length of the chisel edge (404) is 0.2:6 to 0.6:16 of the diameter of the outer circle of the working part (4).

2. The long-life, high-efficiency drill bit according to claim 1, characterized in that: The main flank face (403) includes a main cutting edge (402) for cutting the workpiece, and the projection of the main cutting edge (402) in a projection plane perpendicular to the central axis of the drill bit is a convex curved shape.

3. The long-life, high-efficiency drill bit according to claim 2, characterized in that: The projection of the main cutting edge (402) onto a projection plane perpendicular to the drill bit's central axis results in a curved shape.

4. The long-life, high-efficiency drill bit according to claim 1, characterized in that: The main flank face (403) includes a main cutting edge (402) for cutting the workpiece. The main cutting edge (402) includes a cutting connecting edge connected to the chisel edge (404). The projection of the cutting connecting edge in the projection plane perpendicular to the drill bit's central axis is a broken line, and the cutting edge line of the cutting connecting edge also protrudes in the cutting direction.

5. A long-life, high-efficiency drill bit according to claim 1, characterized in that: Each of the main back face (403) is provided with a plurality of dividing steps (405), and the height of the plurality of dividing steps (405) decreases sequentially along the direction of the transverse cutting edge (404) toward the outer edge of the main back face (403).

6. A long-life, high-efficiency drill bit according to claim 5, characterized in that: The two adjacent split steps (405) are connected by a connecting arc surface.

7. A long-life, high-efficiency drill bit according to claim 1, characterized in that: The main flank face (403) includes a main cutting edge (402) for cutting the workpiece. The projection of each main cutting edge (402) in the projection plane passing through the drill bit's central axis includes the outermost main cutting edge as the first main cutting edge (4021). The included angle between the two symmetrical first main cutting edges (4021) is 145° to 155°.

8. A long-life, high-efficiency drill bit, comprising a tool holder (1) and a working part (4), wherein the working part (4) is coaxial with the tool holder (1), characterized in that: The working part (4) includes two main back face (403), each of the main back face (403) is provided with a number of cutting steps (405), and the height of the number of cutting steps (405) decreases sequentially along the direction of the transverse cutting edge (404) toward the outer edge of the main back face (403).

9. A long-life, high-efficiency drill bit according to claim 8, characterized in that: Two adjacent split steps (405) are connected by a connecting arc surface, and the projection of the connecting arc surface in the projection plane passing through the central axis of the drill bit is arc-shaped.

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