Double-margin twist drill
By designing an arc-shaped cutting edge that intersects with the back edge and an oil guide groove on the twist drill, the problem of chips damaging the hole wall is prevented from entering the concave space, thus achieving a high-quality hole machining effect.
Patent Information
- Application Number
- CN202520115198.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-01-17
AI Technical Summary
In existing technologies, when machining cast iron or mold steel with a certain degree of hardness, chips easily enter between the twist drill and the hole wall, leading to a decrease in the surface quality of the hole wall and even causing the twist drill to break, thus affecting the machining quality and precision.
Design a double-edged twist drill with an arc-shaped cutting edge that intersects with the back edge. Combined with an oil guide groove, it prevents chips from entering the concave space and allows cutting fluid to flow into the concave space through the oil guide groove, providing a flexible guiding effect and preventing chips from damaging the hole wall.
It effectively avoids chip damage to the hole wall surface, improves hole machining quality, enhances guidance, prevents chip clogging and twist drill breakage, and improves machining accuracy and surface quality.
Smart Images
Figure CN223833520U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of metal cutting tool technology, specifically to a double-edged twist drill. Background Technology
[0002] Drilling is a semi-enclosed machining process. Due to the poor working conditions, vibrations are easily generated during the process, leading to deviations in hole straightness, roundness, and surface roughness, resulting in scrapped parts. To solve this problem, in optimizing the structure of twist drills, existing technology typically involves designing an additional pair of "parallel" cutting edges on the outer circumference of the cutting edge of a standard single-flute twist drill. This enhances the guiding effect of the cutting edges on the twist drill's machining process. This structural design technology has proven to be an effective measure that significantly improves hole dimensional accuracy and surface quality.
[0003] However, when machining cast iron or mold steel with a certain hardness, powdery or fine "C-shaped" chips are generated. These small chips are very likely to enter the narrow space between the two cutting bands on the same cutting edge of the twist drill and the hole wall along the chisel edge and the flank face. If the cutting parameters or the depth of the hole being machined are large, the chips crowded between the cutting edge and the hole wall will have difficulty being smoothly discharged from the hole opening with the flow of coolant. Moreover, they will form extrusion marks and scratches on the hole wall surface, reducing the surface quality of the hole. In severe cases, the large torque generated by the chip congestion may even cause the twist drill to break, resulting in the scrap of the part. Utility Model Content
[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a double-edged twist drill that avoids chip damage to the hole wall surface and improves the hole processing quality.
[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0006] A double-edged twist drill includes a cutting section and a shank. The cutting section includes a drill tip and at least two cutting edges, with a helical chip removal groove formed between adjacent cutting edges. The drill tip has a main cutting edge and a back edge. The cutting edges have a first cutting edge, a second cutting edge, and an arc-shaped cutting edge. The first and second cutting edges both extend helically around the central axis of the cutting section. The first cutting edge intersects with the helical chip removal groove to form a secondary cutting edge, which is connected to the main cutting edge. The second cutting edge is arranged behind the first cutting edge along the cutting direction. The arc-shaped cutting edge intersects with the back edge and connects the first and second cutting edges. A concave space is formed between the first, second, and arc-shaped cutting edges and the shank. The arc-shaped cutting edge has at least one oil guide groove arranged axially along the cutting section.
[0007] As a further improvement to the above technical solution:
[0008] The cutting diameter of the cutting part is set as D, and the maximum width of the arc-shaped cutting band is set as w, satisfying D / 40≤w≤D / 20.
[0009] The width of the oil guide groove is set to L2, which satisfies 0.2≤L2≤0.6.
[0010] The depth of the oil guide groove is set to L3, satisfying 0.2 < L3 ≤ 0.6.
[0011] The first and second cutting edges have the same helix angle, denoted as β, satisfying: 10°≤β≤50°.
[0012] On a cross section perpendicular to the cutting part, the line connecting the first cutting edge and the central axis of the cutting part is designated as S1, the line connecting the second cutting edge and the central axis of the cutting part is designated as S2, and the included angle between S1 and S2 is designated as α, satisfying 20°≤α≤80°.
[0013] The first and second cutting edges have equal radial widths, denoted as L4, satisfying D / 25≤L4≤D / 15.
[0014] The minimum distance between the oil guide groove and the secondary cutting edge is set to L5, which satisfies L5=L4+0.1.
[0015] The oil guide groove is provided in multiple ways, and the distance between adjacent oil guide grooves is set to L6, which satisfies 0.2≤L6≤0.4.
[0016] The oil guide grooves are evenly distributed along the extension direction of the arc-shaped blade.
[0017] Compared with the prior art, the advantages of this utility model are:
[0018] This invention relates to a double-edged twist drill with an arc-shaped cutting edge that intersects with the back edge and connects the first and second cutting edges. During machining, the arc-shaped cutting edge prevents chips from entering the concave space, thus avoiding chip damage to the hole wall surface and the formation of extrusion marks and scratches. The size of the oil guide groove is designed to prevent chips from passing through while allowing cutting fluid to pass through. This allows the cutting fluid to flow into the concave space while preventing chips from entering. The cutting fluid enters the concave space through the oil guide groove and, under pressure from the hole wall, generates a flexible guiding effect, thereby enhancing guidance and improving the quality of hole machining. Attached Figure Description
[0019] Figure 1 This is a front view structural schematic diagram of Embodiment 1 of the double-edged twist drill of this utility model.
[0020] Figure 2 This is a side view structural schematic diagram of Embodiment 1 of the double-edged twist drill of this utility model.
[0021] Figure 3 yes Figure 1 Cross-sectional view of AA.
[0022] Figure 4 This is a schematic diagram of the unfolded structure of the concave space in Embodiment 1 of the present invention, which features a double-edged twist drill.
[0023] Figure 5 yes Figure 4 Schematic diagram of the cross-sectional structure of BB.
[0024] Figure 6 This is a schematic diagram of the main structure of Embodiment 2 of the present invention, which features a double-edged twist drill.
[0025] Figure 7 This is a side view of a second embodiment of the double-edged twist drill of this utility model.
[0026] Figure 8 yes Figure 6 Cross-sectional view of DD.
[0027] Figure 9 This is a schematic diagram of the unfolded structure of the concave space in Embodiment 2 of the present invention, which is a double-edged twist drill.
[0028] Figure 10 yes Figure 9 A cross-sectional view of the CC structure.
[0029] The labels in the diagram represent:
[0030] 1. Shank; 2. Cutting section; 3. Drill tip; 31. Main cutting edge; 32. Secondary cutting edge; 33. Back edge; 4. Spiral chip removal groove; 5. Cutting edge; 6. Concave space; 61. First cutting edge; 62. Second cutting edge; 8. Arc-shaped cutting edge; 9. Oil guide groove. Detailed Implementation
[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0032] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "assembly," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0035] Example 1:
[0036] Figures 1 to 5 This invention illustrates an embodiment of a double-edged twist drill. The double-edged twist drill of this embodiment includes a cutting section 2 and a shank 1. The cutting section 2 includes a drill tip 3 and at least two cutting edges 5. A spiral chip removal groove 4 is formed between adjacent cutting edges 5. The drill tip 3 is provided with a main cutting edge 31 and a back edge 33. The cutting edges 5 are provided with a first cutting edge 61, a second cutting edge 62, and an arc-shaped cutting edge 8. Both the first cutting edge 61 and the second cutting edge 62 extend spirally around the central axis of the cutting section 2. The first cutting edge 61 intersects with the spiral chip removal groove 4 to form a secondary cutting edge 32, which is connected to the main cutting edge 31. The second cutting edge 62 is arranged along the cutting direction behind the first cutting edge 61. The arc-shaped cutting edge 8 intersects with the back edge 33 and connects the first cutting edge 61 and the second cutting edge 62. A concave space 6 is formed between the first cutting edge 61, the second cutting edge 62, the arc-shaped cutting edge 8, and the shank 1. The arc-shaped cutting edge 8 is provided with at least one oil guide groove 9 arranged axially along the cutting section 2.
[0037] This double-edged twist drill features an arc-shaped cutting edge 8 that intersects with the back edge 33 and connects the first cutting edge 61 and the second cutting edge 62. During machining, the arc-shaped cutting edge 8 prevents chips from entering the concave space 6, thus avoiding chip damage to the hole wall surface and the formation of extrusion marks and scratches. The size of the oil guide groove 9 is designed to prevent chips from passing through while allowing cutting fluid to pass through. It allows cutting fluid to flow into the concave space 6 while preventing chips from entering. The cutting fluid enters the concave space 6 through the oil guide groove 9 and, under pressure from the hole wall, generates a flexible guiding effect, thereby enhancing guidance and improving the hole machining quality.
[0038] Furthermore, on a cross section perpendicular to the cutting portion 2, the diameter of the arc-shaped cutting edge 8 is equal to the diameter of the cutting portion 2, further preventing chips from entering the concave space 6 during machining. The concave space 6 connects the concave space 6 with the external space of the concave space 6.
[0039] Furthermore, in this embodiment, the cutting diameter of the cutting part 2 is set as D, and the maximum width of the arc-shaped cutting edge 8 is set as w, satisfying D / 40≤w≤D / 20. The width w of the arc-shaped cutting edge 8 needs to be set to a reasonable value. If the value of w is too large, it will increase the friction with the side wall of the workpiece. Therefore, w satisfies: D / 40≤w≤D / 20. Preferably, D=10mm, w=0.4mm.
[0040] Furthermore, in this embodiment, the width of the oil guide groove 9 is set to L2, satisfying 0.2≤L2≤0.6.
[0041] Furthermore, in this embodiment, the depth of the oil guide groove 9 is set to L3, satisfying 0.2 < L3 ≤ 0.6.
[0042] The width L2 and depth L3 of the oil guide groove 9 need to be set to reasonable values to avoid chips entering the concave space 6 due to excessively large values, which would cause the chips to scratch the surface of the hole wall. L2 and L3 satisfy: 0.2≤L2≤0.6, 0.2≤L3≤0.6. Preferably, L2=0.4mm, L3=0.4mm.
[0043] Furthermore, such as Figure 1 As shown, in this embodiment, the helix angles of the first cutting edge 61 and the second cutting edge 62 are the same, denoted as β, satisfying: 10°≤β≤50°. Preferably, β=30°.
[0044] Furthermore, such as Figure 3 As shown, in this embodiment, on a cross section perpendicular to the cutting part 2, the line connecting the first cutting edge 61 and the central axis of the cutting part 2 is designated as S1, and the line connecting the second cutting edge 62 and the central axis of the cutting part 2 is designated as S2. The included angle between S1 and S2 is designated as α, satisfying 20°≤α≤80°, which is beneficial for ensuring a better guiding effect. Preferably, α=50°.
[0045] In a section perpendicular to the cutting portion 2 and passing through the starting points of the first cutting edge 61 and the second cutting edge 62, the angle between the first cutting edge 61 and the second cutting edge 62 in the circumferential direction of the cutting portion 2 is also α, where α satisfies: 20°≤α≤80°. Preferably, α=50°.
[0046] Furthermore, such as Figure 4 As shown, in this embodiment, the radial widths of the first cutting edge 61 and the second cutting edge 62 are equal, set as L4, satisfying D / 25≤L4≤D / 15. Preferably, L4=0.5mm.
[0047] Furthermore, in this embodiment, as Figure 5 As shown, the minimum distance between the oil guide groove 9 and the secondary cutting edge 32 is set to L5, satisfying L5=L4+0.1. Preferably, L5=0.6mm.
[0048] Furthermore, in this embodiment, there is only one oil guide groove 9.
[0049] Furthermore, in this embodiment, the cutting part 2 includes two cutting edges 5, and correspondingly, the drill tip 3 is provided with two main cutting edges 31. The first cutting edge 61 intersects with the corresponding spiral chip removal groove 4 to form a secondary cutting edge 32, and the secondary cutting edge 32 is connected to the corresponding main cutting edge 31.
[0050] Example 2:
[0051] Figures 6 to 10 This paper illustrates another embodiment of the double-edged twist drill of the present invention. The structure of the double-edged twist drill in this embodiment is basically the same as that in Embodiment 1, except that: multiple oil guide grooves 9 are provided, and the distance between adjacent oil guide grooves 9 is set to L6, satisfying 0.2≤L6≤0.4. Preferably, L6=0.4mm.
[0052] Furthermore, in this embodiment, the oil guide grooves 9 are evenly distributed along the extension direction of the arc-shaped blade strip 8.
[0053] For example, three oil guide grooves 9 are provided on the arc-shaped cutting edge 8. The oil guide grooves 9 are evenly distributed on the arc-shaped cutting edge 8, and the interval between adjacent oil guide grooves 9 is L6. L6 satisfies: 0.2≤L6≤0.4.
[0054] Example 3:
[0055] The double-edged twist drill of this embodiment is basically the same as that of Embodiment 1 or Embodiment 2, except that: the cutting part 2 includes three cutting edges 5 and three spiral chip removal grooves 4, and correspondingly, the drill tip 3 is provided with three main cutting edges 31. The first cutting edge 61 intersects with the corresponding spiral chip removal groove 4 to form a secondary cutting edge 32, and the secondary cutting edge 32 is connected to the corresponding main cutting edge 31.
[0056] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the present invention, or modify it into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, should fall within the protection scope of the present invention.
Claims
1. A double-edged twist drill, comprising a cutting portion (2) and a shank portion (1), wherein the cutting portion (2) comprises a drill tip (3) and at least two cutting edges (5), a spiral chip removal groove (4) is formed between adjacent cutting edges (5), and the drill tip (3) is provided with a main cutting edge (31) and a back edge (33), characterized in that: The cutting edge (5) is provided with a first cutting edge (61), a second cutting edge (62) and an arc-shaped cutting edge (8). The first cutting edge (61) and the second cutting edge (62) both extend spirally around the central axis of the cutting part (2). The first cutting edge (61) intersects with the spiral chip removal groove (4) to form a secondary cutting edge (32). The secondary cutting edge (32) is connected to the main cutting edge (31). The second cutting edge (62) is arranged on the rear side of the first cutting edge (61) along the cutting direction. The arc-shaped cutting edge (8) intersects with the back edge (33) and connects the first cutting edge (61) and the second cutting edge (62). An inward space (6) is formed between the first cutting edge (61), the second cutting edge (62), the arc-shaped cutting edge (8) and the shank (1). The arc-shaped cutting edge (8) is provided with at least one oil guide groove (9) arranged along the axial direction of the cutting part (2).
2. The double-edged twist drill according to claim 1, characterized in that: The cutting diameter of the cutting part (2) is set to D, and the maximum width of the arc-shaped cutting band (8) is set to w, satisfying D / 40≤w≤D / 20.
3. The double-edged twist drill according to claim 1, characterized in that: The width of the oil guide groove (9) is set to L2, which satisfies 0.2≤L2≤0.
6.
4. The double-edged twist drill according to claim 1, characterized in that: The depth of the oil guide groove (9) is set to L3, satisfying 0.2<L3≤0.
6.
5. The double-edged twist drill according to claim 1, characterized in that: The first cutting edge (61) and the second cutting edge (62) have the same helix angle, denoted as β, which satisfies: 10°≤β≤50°.
6. The double-edged twist drill according to claim 1, characterized in that: On a cross section perpendicular to the cutting part (2), the line connecting the first cutting edge (61) and the central axis of the cutting part (2) is set as S1, and the line connecting the second cutting edge (62) and the central axis of the cutting part (2) is set as S2. The included angle between S1 and S2 is set as α, satisfying 20°≤α≤80°.
7. The double-edged twist drill according to claim 1, characterized in that: The first cutting edge (61) and the second cutting edge (62) have equal radial widths, set as L4, satisfying D / 25≤L4≤D / 15.
8. The double-edged twist drill according to claim 1, characterized in that: The minimum distance between the oil guide groove (9) and the secondary cutting edge (32) is set to L5, which satisfies L5=L4+0.
1.
9. The double-edged twist drill according to any one of claims 1 to 8, characterized in that: The oil guide groove (9) is provided in multiple ways, and the distance between adjacent oil guide grooves (9) is set to L6, which satisfies 0.2≤L6≤0.
4.
10. The double-edged twist drill according to claim 9, characterized in that: The oil guide grooves (9) are evenly distributed along the extension direction of the arc-shaped blade (8).