Centering double-edge drill

Abstract

The utility model discloses a centering double-edge drill which comprises a drill handle and a drill body, two spiral blades are arranged on the drill body, and a first spiral chip groove is formed between the two spiral blades. A first margin is arranged on the front side of the spiral blade, a cutting edge is arranged on the front side of the top of the first margin, a second margin is arranged on the rear side of the spiral blade, and a slope is arranged on the top of the second margin. The outer diameter of the first edge strip is the same as that of the second edge strip, a second spiral chip removal groove is formed between the first edge strip and the second edge strip, the first spiral chip removal groove and the second spiral chip removal groove are independent from each other, and the radial depth of the second spiral chip removal groove is 1 / 3-1 / 2 of the outer radius of the spiral edge section. According to the drill bit, the two blade strips and the two spiral chip grooves are arranged, during cutting, the first blade strip is used for cutting, the first spiral chip groove is used for smoothly discharging chips generated during drilling, the second blade strip is used for smoothly discharging chips repaired by an inner hole in the second spiral chip groove, and the situation that the chips cause extrusion marks and scars on the surface of the wall of the inner hole is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of metal cutting, in particular to a centering double-edged drill. Background Art

[0002] Drilling is different from milling, turning and other processing methods. It is a semi-closed processing. Due to poor processing conditions, vibration is easily generated during the processing, resulting in poor straightness, roundness, surface roughness, etc. of the hole, which can easily cause parts to be scrapped. In order to solve such problems, in terms of twist drill structure optimization, the existing technology usually designs a pair of edge bands "parallel" to the existing edge bands on the outer peripheral surface of the edge petal of an ordinary single-edge twist drill to enhance the guiding effect of the edge band on the twist drill processing process.

[0003] However, strengthening the guiding function of the edge band is only one of the technical issues that need to be addressed during the design process of the twist drill. The workpiece materials faced by the twist drill in mechanical processing are diverse. When the twist drill is used to process cast iron or mold steel materials with a certain hardness, powdery or fine "C-shaped" chips are generated. These small chips are very likely to enter the narrow area surrounded by the two edge bands on the same edge of the twist drill and the hole wall along the grinding surface of the cross blade and the back knife surface. If the cutting parameters or the depth of the processed hole are large at this time, the chips crowded between the edge flap and the hole wall will be difficult to discharge smoothly, and will form extrusion marks and scratches on the surface of the hole wall, reducing the surface quality of the hole. In severe cases, the twist drill may even break due to the large torque generated by the chip congestion, resulting in the scrapping of the part. Utility Model Content

[0004] In view of the shortcomings of the current existing technology, the purpose of the centering multi-edge drill of the utility model is to realize direct drilling in the drilling process during mechanical processing, avoid the accumulation of chips in the spiral groove during processing, prevent the formation of extrusion marks and scars on the inner wall surface of the hole, and the inner wall of the drilled hole is smoother, thereby improving the surface quality of the hole.

[0005] In order to achieve the above-mentioned purpose, the utility model is specifically realized through the following technical solutions:

[0006] A centering double-edge drill comprises a drill shank and a drill body, wherein two spiral blades are arranged on the drill body, and a first spiral chip groove is formed between the two spiral blades; a first edge band is arranged on the front side of the spiral blade, and the front side of the top of the first edge band is a cutting edge, and a second edge band is arranged on the rear side of the spiral blade, and the top of the second edge band has an inclined surface; the outer diameters of the first edge band and the second edge band are the same, and a second spiral chip groove is arranged between the first edge band and the second edge band, and the first spiral chip groove and the second spiral chip groove are independent of each other, and the radial depth of the second spiral chip groove is 1 / 3-1 / 2 of the outer radius of the spiral blade; the spiral angle of the first edge band is 28°-42°, and the spiral angle of the second edge band is 1°-2° larger than the spiral angle of the first edge band.

[0007] Furthermore, the angle between the inclined surface and the central axis of the drill body is 30°-40°.

[0008] Furthermore, a chisel edge is formed at a connection between the second edge slope of one spiral edge petal and the first edge cutting edge of another spiral edge petal.

[0009] Furthermore, the inner side of the chisel edge and the bottom surface of the first spiral chip removal groove form a concave transition edge, and the angle β between the transition edge and the central axis of the drill body is 4°-10°.

[0010] Furthermore, the cross section of the second spiral chip removal groove is an arc groove shape.

[0011] Furthermore, the top outer edge of the first cutting edge has an exit edge, and the angle γ between the exit edge and the central axis of the drill body is 74°-83°.

[0012] Furthermore, a top edge is provided at the center of the top of the drill body, and the width of the top edge is 0.1-0.35 mm.

[0013] Further, the groove length L1 of the first spiral chip groove is greater than the groove length L2 of the second spiral chip groove.

[0014] The technical solution of the utility model provides two cutting edges and two spiral chip grooves. During cutting, the first cutting edge performs cutting, and the first spiral chip groove smoothly discharges chips generated during drilling. Meanwhile, the spiral angle of the first cutting edge is smaller than the spiral angle of the second cutting edge. Accordingly, the spiral angle of the first spiral chip groove is smaller than the spiral angle of the second spiral chip groove. The second cutting edge performs two follow-up repairs on the inner hole, and the repaired chips are smoothly discharged from the second spiral chip groove. The chips generated are all broken chips when they are smoothly discharged, thereby avoiding extrusion marks and scratches on the inner hole wall surface caused by cutting, and improving the accuracy and smoothness of the inner hole surface.

[0015] The first edge is flush with the outer edge of the second edge. During processing, the first edge is used for cutting and the second edge is used for repairing, so that the inner wall of the hole is smooth and the accuracy of the hole diameter is guaranteed. The back blade surface of the top surface of the spiral blade is sloped, with the front end high and the rear end low to form an inclined surface, forming a transition edge and a transverse edge at the top of the spiral blade to prepare for drilling centering and cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0017] Figure 2 It is a schematic diagram of the structure on one side of the top of the drill body;

[0018] Figure 3 It is a schematic diagram of the structure on the top side of the drill body.

[0019] In the figure, 1-drill shank; 2-drill body; 3-spiral blade; 4-first spiral chip groove; 5-first edge band; 6-cutting edge; 7-second edge band; 8-bevel; 9-second spiral chip groove; 10-center axis of drill body; 11-transverse edge; 12-transition edge; 13-exit edge; 14-top edge. DETAILED DESCRIPTION

[0020] The utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] In the description of the embodiments of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0022] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0023] In the description of this specification, the description with reference to the terms "in an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model embodiment. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0024] like Figures 1 to 3As shown, a centering double-edge drill of the utility model comprises a drill shank 1 and a drill body 2, two spiral blades 3 are arranged on the drill body 2, and a first spiral chip removal groove 4 is formed between the two spiral blades 3; a first edge band 5 is arranged on the front side of the spiral blade 3, and a cutting edge 6 is arranged on the front side of the top of the first edge band 5, and a second edge band 7 is arranged on the rear side of the spiral blade 3, and a bevel 8 is arranged on the top of the second edge band 7. The outer diameters of the first edge band 5 and the second edge band 7 are the same, and the outer sides of the first edge band 5 and the second edge band are flush, and during processing, the second edge band is repaired after the first edge band is cut to avoid smoothness, while ensuring the accuracy of the aperture.

[0025] A second spiral chip groove 9 is provided between the first edge band 5 and the second edge band 7. The first spiral chip groove 4 and the second spiral chip groove 9 are independent of each other. The radial depth of the second spiral chip groove 9 is 1 / 3-1 / 2 of the outer radius of the spiral edge 3. Preferably, the cross section of the second spiral chip groove 9 is an arc groove. The second spiral chip groove 9 is used to smoothly discharge the chips produced by the second edge band 7 repairing the inner hole twice.

[0026] The helical angle α of the first edge band 5 is 28°-42°, and the helical angle α can be selected according to different types and models of drill bits. The helical angle of the second edge band 7 is 1°-2° larger than the helical angle of the first edge band 5, which improves the amount of debris of the product during the drilling and cutting process, and facilitates the smooth discharge of debris. The second edge band 7 is used for follow-up secondary repairs of the drilled inner hole, and the repaired debris is smoothly discharged from the second spiral chip groove 9. The thickness of the tail end of the second spiral chip groove 9 is greater than the thickness of the head end, and the second spiral chip groove 9 has a smooth transition from the head end to the tail end, which better ensures the strength of the drill body.

[0027] In the preferred embodiment, the angle β between the bevel 8 and the central axis 10 of the drill body is 30°-40°. The bevel 8 is equivalent to the back side of the back face of the cutting edge 6 being sloped, which can reduce the weight of the top of the drill body and improve the drilling centering degree on the one hand, and can make the chips cut from the top dispersed and smoothly enter the first spiral chip groove 4 and the second spiral chip groove 9 on the other hand, avoiding the generation of extrusion marks and scars on the surface of the inner hole wall caused by a large amount of chips from the top.

[0028] Preferably, the inclined surface 8 of the second edge band 7 on one spiral edge petal 3 and the cutting edge 6 of the first edge band 5 of another spiral edge petal 3 form a chisel edge 11. Further preferably, the inner side of the chisel edge 11 forms a concave transition edge 12 with the bottom surface of the first spiral chip groove 4, and the angle γ between the transition edge 12 and the central axis 10 of the drill body is 4°-10°. The chisel edge 11 further performs drilling and centering on the inner hole, and chip removal is smooth.

[0029] Preferably, the top outer edge of the first cutting edge has an exit ridge 13, and the angle δ between the exit ridge and the central axis of the drill body is 74°-83°.

[0030] In the preferred embodiment, the top center of the drill body 2, i.e., the drill tip, has a top blade 14, and the width of the top blade 14 is 0.1-0.35 mm. The top blade 14 is connected to the transverse blade 11 at both ends. In the twist drill, the angle between the two transverse blades 11 is 125°-145°, and the top blade 14 and the transverse blade 11 are better prepared for drilling centering and cutting.

[0031] Preferably, the groove length L1 of the first spiral chip groove 4 is greater than the groove length L2 of the second spiral chip groove 9, and the two spiral chip grooves end at different positions of the drill body 2, which can avoid excessive concentration of debris when discharging the drill body.

[0032] The specific embodiments in the present invention are merely explanations of the present invention, and are not limitations of the present invention. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A centering double-edged drill, comprising a drill shank (1) and a drill body (2), characterized in that: Two spiral blades (3) are arranged on the drill body, and a first spiral chip groove (4) is formed between the two spiral blades; a first edge band (5) is arranged on the front side of the spiral blade, and the front side of the top of the first edge band is a cutting edge (6); a second edge band (7) is arranged on the rear side of the spiral blade, and the top of the second edge band has a bevel (8); the first edge band and the second edge band have the same outer diameter, and a second spiral chip groove (9) is arranged between the first edge band and the second edge band, the first spiral chip groove and the second spiral chip groove are independent of each other, and the radial depth of the second spiral chip groove is 1 / 3-1 / 2 of the outer radius of the spiral blade; the spiral angle α of the first edge band is 28°-42°, and the spiral angle of the second edge band is 1°-2° larger than the spiral angle of the first edge band.

2. The centering double-edged drill according to claim 1, characterized in that: The included angle β between the inclined surface and the central axis (10) of the drill body is 30°-40°.

3. The centering double-edged drill according to claim 1, characterized in that: A chisel edge (11) is formed at the connection between the second edge slope of one spiral edge petal and the first edge cutting edge of another spiral edge petal.

4. The centering double-edged drill according to claim 3, characterized in that: The inner side of the chisel edge and the bottom surface of the first spiral chip removal groove form an inwardly concave transition edge (12), and the angle γ between the transition edge and the central axis of the drill body is 4°-10°.

5. The centering double-edged drill according to claim 1, characterized in that: The cross section of the second spiral chip removal groove is an arc groove shape.

6. The centering double-edged drill according to claim 1, characterized in that: The outer edge of the top of the first cutting edge is provided with an exit ridge (13), and the angle between the exit ridge and the central axis of the drill body is 74°-83°.

7. The centering double-edged drill according to claim 1, characterized in that: A top edge (14) is provided at the center of the top of the drill body, and the width of the top edge is 0.1-0.35 mm.

8. The centering double-edged drill according to claim 1, characterized in that: The groove length L1 of the first spiral chip groove is greater than the groove length L2 of the second spiral chip groove.

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