Deep hole drill

Abstract

The invention provides a deep hole drill which comprises a drill body, the drill body comprises a drilling section, the drilling section comprises a drill core, a cutting edge is formed at a drill point of the drill core, the drilling section further comprises a plurality of edge strips which are spirally arranged in the axial direction of the drill core, an overflowing groove is formed in the guide face of at least part of the edge strips, and the overflowing groove is formed in the guide face of at least part of the edge strips. A cooling liquid channel capable of guiding cooling liquid to the drill tip is formed in the drilling section. According to the invention, the contact area of the cooling liquid and the edge strip is increased, the efficient cooling and heat dissipation of the edge strip are realized, the thermal crack phenomenon of the edge strip caused by high temperature generated by cutting of the cutting edge is avoided, the phenomena of tool failure and product scrapping caused by the thermal crack are further avoided, and the drilling efficiency of the deep hole drill is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling tool design, and in particular relates to a deep hole drill. Background Art

[0002] In the modern mechanical processing industry, mold processing is an indispensable part of the current manufacturing industry. In the mold manufacturing process, deep hole processing of internal coolant holes and ejector holes must be performed on the mold. Traditional gun drilling can no longer meet the pursuit of processing efficiency in modern mold processing. Therefore, it is urgent to use deep hole drilling (drilling depth is generally greater than 5 times the drill diameter) for mold processing.

[0003] Hole machining is carried out in a closed or semi-closed state, with a large machining allowance, and it is impossible to observe the real-time cutting situation of the tool. The machining process is difficult, which is mainly reflected in: the temperature in the cutting area is high, and the cutting heat is not easy to transfer; the chip removal distance is long, and the chip removal is difficult; the process system has poor rigidity and is prone to vibration during the drilling process; due to the high temperature and high pressure in the drilling area, the drill tip is prone to wear. Especially during the drilling process, the inner part of the hole of the drilling part of the cutting edge used to guide the drill body is very likely to produce thermal cracks under the action of high temperature, which will lead to tool failure, product scrapping and reduce the efficiency of deep hole drilling. Summary of the invention

[0004] Therefore, the present invention provides a deep hole drill that can overcome the technical problem in the related art that the inner hole portion of the blade band of the deep hole drill is very likely to produce thermal cracks under high temperature, thereby causing tool failure, product scrapping and reducing the drilling efficiency of the deep hole drill.

[0005] In order to solve the above problems, the present invention provides a deep hole drill, including a drill body, the drill body including a drilling section, the drilling section including a drill core, a cutting edge formed at the drill tip of the drill core, the drilling section also including a plurality of cutting bands spirally arranged along the axial direction of the drill core, at least part of the guide surfaces of the cutting bands are configured with overflow grooves, and a coolant channel capable of guiding coolant to the drill tip is formed in the drilling section.

[0006] In some embodiments, the cutting band has a first side surface and a second side surface connected to its guide surface, the flow groove passes through the first side surface and the second side surface, the cutting band intersects the cutting edge at point A, the tangent line passing through point A and tangent to the cutting edge is the first tangent line, and the through extension direction of the flow groove is parallel to the first tangent line; and / or, the cutting edge has m strips, and the cutting band has 2m strips, wherein the m strips are connected one by one to each cutting edge to form a cutting band as a first cutting band, and each of the flow grooves is constructed on the first cutting band.

[0007] In some embodiments, on any of the margins, n flow grooves are arranged at intervals along the axial direction of the drill core, and the minimum distance between the groove wall of the flow groove closest to the drill tip and the cutting edge is I, where I = 0.0264*n 2 +0.073*H, wherein H is the width of the land.

[0008] In some embodiments, on the same edge band, the distance between two adjacent flow grooves increases in a direction away from the drill tip.

[0009] In some embodiments, the spacing between the i-th flow groove and the i-1-th flow groove is (0.5+0.25i)H, where i is a natural number not less than 2.

[0010] In some embodiments, the flow groove is a V-shaped groove, the groove depth of the flow groove is E, E = 0.6mm ~ 0.12mm; and / or, the groove wall inclination angle of the flow groove close to the drill tip side is F, F = 30° ~ 40°.

[0011] In some embodiments, the drill core includes an axial front section and an axial rear section continuously arranged along the axial direction thereof, wherein the axial front section is an equal-diameter section, and the axial rear section is a conical section whose diameter gradually decreases along the side away from the drill tip, and each of the flow grooves is formed on each of the cutting bands corresponding to the axial front section.

[0012] In some embodiments, the axial length of the equal diameter section is L1, and the diameter is d, L1 = 2.5D to 3D, and / or d = 0.25D to 0.4D, wherein D is the outer diameter of the drilling section.

[0013] In some embodiments, the axial length of the inverted cone section is L2, the taper of the inverted cone section is T, and the axial length L2 and the taper T satisfy the following formula:

[0014]

[0015] In some embodiments, the top angle of the drill tip is A, 137°≤A≤147°, the back angle of the drill tip is B, 9°≤B≤15°, the helix angle of the cutting edge is C, 27°≤C≤29°; and / or the deep hole drill further includes a shank segment and a clearance segment between the shank segment and the drilling segment.

[0016] In some embodiments, A=138°, B=8.5°, and C=27.5°.

[0017] The deep hole drill provided by the present invention has the following beneficial effects:

[0018] A flow groove is constructed on the guide surface of the edge band. During the deep hole drilling process, the coolant enters the bottom of the deep hole, that is, the drill tip area, through the coolant channel to cool and dissipate the heat of the drill tip area. At the same time, the coolant can also flow through the flow groove, which increases the contact area between the coolant and the edge band, thereby achieving efficient cooling and heat dissipation of the edge band, which can effectively prevent the occurrence of thermal cracks on the edge band caused by the high temperature generated by the cutting edge, thereby preventing tool failure and product scrapping caused by thermal cracks, and improving the drilling efficiency of the deep hole drill;

[0019] On the one hand, the flow groove is arranged on the first edge band connected to the cutting edge, which can effectively reduce the probability of thermal cracks on the edge band connected to the cutting edge due to heat conduction of the cutting edge. On the other hand, the flow groove is not constructed on the edge band not connected to the cutting edge because thermal cracks hardly occur on this part of the edge band, and at the same time, the rigidity of the overall guide part is guaranteed.

[0020] By arranging the through extension direction of the flow groove in parallel with the aforementioned first switch, the aforementioned cutting edge of the deep hole drill and each flow groove can be processed at the same grinding angle, that is, only different grinding tools need to be replaced without adjusting the clamping angle of the grinding tools, which can significantly improve the processing efficiency;

[0021] For the same edge band, the more the number of flow grooves arranged on the guide surface is, the greater the minimum distance I of the flow groove closest to the drill tip is, and vice versa, the smaller it is, so that the balance between the number of flow grooves 1141 and the width of the edge band 114 can be ensured, thereby guiding the reasonable selection of the aforementioned parameters of the deep hole drill and reducing the design difficulty;

[0022] The spacing between two adjacent flow grooves increases in the direction away from the drill tip, that is, decreases in the direction close to the drill tip, so as to give priority to ensuring efficient cooling of the edge band near the drill tip and prevent thermal cracks from being generated there.

[0023] The flow groove is a V-shaped groove with limited groove depth and groove wall inclination angle, which can effectively guide the coolant at the drill tip to the back of the edge band, increase the contact area between the edge band and the coolant, and further improve the cooling effect on the edge band;

[0024] On the one hand, each flow groove is formed on the corresponding edge band on the equal-diameter section, which can ensure the structural rigidity of the equal-diameter section while achieving the cooling effect on the edge band, and ensure the stability of the drilling section during the drilling process. At the same time, since the deep hole drill only uses the drill tip for drilling during drilling, the diameter of the corresponding equal-diameter section is larger than the diameter of the tapered section, so that it can ensure sufficient working strength while also bringing the center of mass closer to the drill tip, which can ensure that the edge band can play a better supporting role during the drilling process; on the other hand, the axial rear section is designed as a tapered section that tapers along the side away from the drill tip. As the core thickness gradually decreases, the natural frequency of the deep hole drill gradually increases, so the frequency that can cause tool resonance needs to be higher, and the stability of the deep hole drill is higher. At the same time, the tapered section with a gradually decreasing diameter also makes the space of the chip groove larger and larger in the direction away from the drill tip, so that the chips can be discharged more smoothly, reducing the risk of deep hole drill breakage.

[0025] The optimized deep hole drill has a 13% longer tool life and a drilling efficiency that is up to 20 times higher than traditional gun drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0027] Figure 1 is a schematic diagram of the overall structure of a deep hole drill in an embodiment of the present invention;

[0028] Figure 2 yes Figure 1 Longitudinal section of deep hole drilling in ;

[0029] Figure 3 yes Figure 1 The overall structural diagram of the deep hole drill in another perspective;

[0030] Figure 4 yes Figure 3 Sectional view of AA in the middle;

[0031] Figure 5 yes Figure 3 Cross-sectional view of the middle BB;

[0032] Figure 6 yes Figure 1 Schematic diagram of the local structure of the deep hole drill;

[0033] Figure 7 yes Figure 1 Schematic diagram of the back angle of the deep hole drill;

[0034] Figure 8 yes Figure 1 Another partial structural schematic diagram of the deep hole drill in FIG.

[0035] Fig. 9 yes Figure 1 Another partial structural schematic diagram of the deep hole drill;

[0036] Fig.10 yes Fig. 9 A partial enlarged view of point A in the middle.

[0037] The accompanying drawings are marked as follows:

[0038] 11. Drilling section; 111. Drill core; 112. Drill tip; 113. Cutting edge; 114. Margin; 1141. Flow groove; 115. Coolant channel; 116. Gash surface; 117. Chip groove; 12. Shank section; 13. Avoidance section. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0041] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0042] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0043] See also Figures 1 to 10 As shown, according to an embodiment of the present invention, a deep hole drill is provided (the ratio of the drilling depth to the drill diameter of the deep hole drill of the present invention is 30 times or more), including a drill body (not labeled in the figure), the drill body includes a drilling section 11, it can be understood that in the specific use process, the drilling section 11 will participate in the formation of the hole, the drilling section 11 includes a drill core 111, and a cutting edge 113 (also known as a main cutting edge, which should be cut in the corresponding area of ​​the cutting object) is formed at the drill tip 112 of the drill core 111. The drilling section 11 further comprises a plurality of cutting edges 114 which are spirally arranged along the axial direction of the drill core 111. During use, the cutting edges 114 abut against the inner wall of the formed hole to support the drill body, thereby ensuring the drilling feed direction and the stability of the drill body. At least a portion of the guide surfaces of the cutting edges 114 (not marked in the figure) are configured with overflow grooves 1141. A coolant channel 115 which can guide the coolant to the drill tip 112 is formed in the drilling section 11.

[0044] In this technical solution, a flow groove 1141 is constructed on the guide surface of the blade 114. During the deep hole drilling process, the coolant enters the bottom of the deep hole, that is, the drill tip 112 area, through the coolant channel 115 to cool and dissipate the drill tip 112 area. At the same time, the coolant can also flow through the flow groove 1141, thereby increasing the contact area between the coolant and the blade 114, thereby achieving efficient cooling and heat dissipation of the blade 114, thereby effectively preventing the blade 114 from thermal cracks caused by the high temperature generated by the cutting edge 113, thereby preventing tool failure and product scrapping caused by thermal cracks, and improving the drilling efficiency of the deep hole drill.

[0045] In some embodiments, the cutting edge 113 has m strips, and the edge band 114 has 2m strips, wherein the m strips are connected to each cutting edge 113 one by one to form the edge band 114 as the first edge band (not marked in the figure), and each of the flow grooves 1141 is constructed on the first edge band. In a specific embodiment of the present invention, there are 2 cutting edges 113 (that is, the aforementioned m=2), and there are 4 edge bands 114, wherein two edge bands 114 are connected to the cutting edge 113, and the other two are not connected to the cutting edge 113, the cutting edges 113 are symmetrically distributed at the drill tip 112, and the 4 edge bands 114 are evenly spaced around the circumference of the drill core 111, and it can be understood that a chip groove 117 is formed between each cutting edge 113 and the corresponding gash surface 116 (that is, the surface between the back tool surface and the chip groove 117), and the aforementioned first edge band also serves as one of the guide surfaces of the aforementioned chip groove 117.

[0046] In this technical solution, on the one hand, the flow groove 1141 is arranged on the first edge band connected to the cutting edge 113, which can effectively reduce the probability of thermal cracks on the edge band 114 connected thereto due to heat conduction of the cutting edge 113. On the other hand, the aforementioned flow groove 1141 is not constructed on the edge band 114 that is not connected to the cutting edge 113 because thermal cracks hardly occur on this part of the edge band 114, and at the same time, the rigidity of the overall guiding part is guaranteed.

[0047] See Figure 1 As shown, the deep hole drill also includes a shank segment 12 and a clearance segment 13 between the shank segment 12 and the drilling segment 11, wherein the shank segment 12 is used to be fixedly connected to a driving device such as a machine tool, and the clearance segment 13 can effectively avoid interference and collision when processing complex structural parts while ensuring the strength of the tool, and reserve space for chip removal.

[0048] In some embodiments, the edge band 114 has a first side surface (specifically, for example, a side close to the chip groove 117) and a second side surface (specifically, for example, a side away from the chip groove 117) connected to its guide surface, and the flow groove 1141 passes through the first side surface and the second side surface, so that the coolant can flow smoothly from one side of the edge band 114 to the other side, ensuring efficient cooling of the coolant on the edge band 114, and the edge band 114 intersects with the cutting edge 113 at point A (see Figure 8 As shown in the figure, the tangent line passing through the point A and tangent to the cutting edge 113 is the first tangent line, and the through extension direction of the flow groove 1141 is parallel to the first tangent line. The aforementioned extension direction is also the grinding feed direction of the grinding tool when the flow groove 1141 is ground.

[0049] In this technical solution, by arranging the through extension direction of the flow groove 1141 in parallel with the aforementioned first switch, the same grinding angle can be used when processing the aforementioned cutting edge of the deep hole drill and each flow groove 1141, that is, only different grinding tools need to be replaced without adjusting the clamping angle of the grinding tool, which can significantly improve the processing efficiency.

[0050] See Figure 8 As shown, in some embodiments, on any of the edge bands 114, n number of the flow grooves 1141 are arranged at intervals along the axial direction of the drill core 111, and the minimum distance between the groove wall of the flow groove 1141 closest to the drill tip 112 and the cutting edge 113 is I, where I = 0.0264*n 2 +0.073*H, wherein H is the width of the land 114 .

[0051] In this technical solution, for the same blade 114, the more flow grooves 1141 are set on its guide surface, the greater the minimum distance I of the flow groove 1141 closest to the drill tip 112, and vice versa. This ensures a balance between the number of flow grooves 1141 and the width of the blade 114, thereby guiding the reasonable selection of the aforementioned parameters of deep hole drilling and reducing the design difficulty.

[0052] In some embodiments, on the same cutting edge 114, the distance between two adjacent flow grooves 1141 increases in the direction away from the drill tip 112. Specifically, the distance between the i-th flow groove 1141 and the i-1-th flow groove 1141 is (0.5+0.25i)H, where i is a natural number not less than 2.

[0053] In this technical solution, the distance between two adjacent flow grooves 1141 becomes larger and larger in the direction away from the drill tip 112, that is, it becomes smaller and smaller in the direction close to the drill tip 112, which can prioritize the efficient cooling of the cutting edge 114 near the drill tip 112 to prevent thermal cracks from occurring there.

[0054] See Fig.10 As shown, in some embodiments, the flow groove 1141 is a V-shaped groove, and the groove depth of the flow groove 1141 is E, E=0.6mm~0.12mm; the groove wall inclination angle of the flow groove 1141 close to the drill tip 112 is F, F=30°~40°.

[0055] In this technical solution, the overflow groove 1141 is a V-shaped groove and the groove depth and the inclination angle of the groove wall are limited, which can well guide the coolant at the drill tip 112 to the back of the edge band 114, so that the contact area between the edge band 114 and the coolant is increased, and the cooling effect on the edge band 114 is further improved. In addition, the overflow groove 1141 is a V-shaped groove, which has a relatively simple structure and is easy to process. Moreover, since the opening size of the V-shaped groove is large, the groove bottom size is small, and the opening is toward one side of the hole wall, the rigidity of the edge band 114 can be guaranteed as much as possible while achieving overflow cooling.

[0056] In some embodiments, the drill core 111 includes an axial front section (ie, Figure 2 The interval represented by L1 in the figure) and the axial posterior segment (i.e. Figure 2 The axial front section is a section of equal diameter (that is, the diameter of the drill core 111 remains unchanged along the axial direction within this section), and the axial rear section is a conical section whose diameter gradually decreases along the side away from the drill tip 112 (that is, the diameter becomes smaller and smaller), and each of the flow grooves 1141 is formed on each of the blades 114 corresponding to the axial front section.

[0057] In this technical solution, on the one hand, each flow groove 1141 is formed on the corresponding edge band 114 on the equal diameter section, which can ensure the structural rigidity of the equal diameter section while achieving the cooling effect on the edge band 114, and ensure the stability of the drilling section 11 during the drilling process. At the same time, since the deep hole drill only uses the drill tip 112 for drilling during drilling, the diameter of the corresponding equal diameter section is larger than the diameter of the tapered section, so that it can ensure sufficient working strength while also being able to move the center of mass close to the drill tip 112, which can ensure that the edge band 114 can play a better supporting role during the drilling process; on the other hand, the axial rear section is designed as a tapered section that tapers along the side away from the drill tip 112. As the core thickness gradually decreases, the natural frequency of the deep hole drill gradually increases. Therefore, the frequency that can cause tool resonance needs to be higher, and the stability of the deep hole drill is higher. At the same time, the tapered section with a gradually decreasing diameter also makes the space of the chip groove 117 larger and larger in the direction away from the drill tip 112, so that the chips can be discharged more smoothly, reducing the risk of deep hole drill breakage.

[0058] In a specific embodiment, the axial length of the equal-diameter section is L1 and the diameter is d, L1=2.5D~3D. It has been verified by experiments that when L1 is within the aforementioned range, the drilling vibration is low, and higher or lower than the vibration is relatively high; and / or, d=0.25D~0.4D, preferably 0.3D. It has been verified by experiments that when d is within the aforementioned range, the drilling vibration is low, and higher or lower than the vibration is relatively high, wherein D is the outer diameter of the drilling section 11.

[0059] In some embodiments, the axial length of the inverted cone section is L2, the taper of the inverted cone section is T, and the axial length L2 and the taper T satisfy the following formula:

[0060]

[0061] In this technical solution, by limiting T, L2 and L1, T can be within a reasonable range, so that the vibration during the drilling process can be reduced while ensuring the overall rigidity of the deep hole drill.

[0062] In some embodiments, the top angle of the drill tip 112 is A, 137°≤A≤147°, preferably A=138°, to prevent excessive axial force; the back angle of the drill tip 112 is B, 9°≤B≤15°, preferably B=8.5°. It has been verified that when B is less than 9°, drilling will cause interference, resulting in tool breakage, while when it is greater than 15°, the drill tip strength will be reduced; the helix angle of the blade 114 is C, 27°≤C≤29°, preferably C=27.5°. It has been verified by experiments that when the aforementioned helix angle C is lower than 27° or higher than 29°, the axial force of the deep hole drill will increase, the drilling temperature will increase, and the tool life will be reduced.

[0063] The optimized deep hole drill has a 13% longer tool life and a drilling efficiency that is up to 20 times higher than traditional gun drilling.

[0064] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A deep hole drill, characterized in that: The drill body comprises a drill section (11), the drill section (11) comprises a drill core (111), a cutting edge (113) is formed at a drill tip (112) of the drill core (111), the drilling section (11) further comprises a plurality of cutting edges (114) spirally arranged along the axial direction of the drill core (111), at least a portion of the guiding surfaces of the cutting edges (114) are configured with overflow grooves (1141), and a coolant channel (115) capable of guiding coolant to the drill tip (112) is formed in the drilling section (11).

2. The deep hole drill according to claim 1, characterized in that: The cutting band (114) has a first side surface and a second side surface connected to its guide surface, the flow groove (1141) passes through the first side surface and the second side surface, the cutting band (114) intersects with the cutting edge (113) at point A, the tangent line passing through point A and tangent to the cutting edge (113) is the first tangent line, and the through extension direction of the flow groove (1141) is parallel to the first tangent line; and / or, the cutting edge (113) has m strips, and the cutting band (114) has 2m strips, wherein the m strips are connected one by one to each cutting edge (113) to form a cutting band (114) as a first cutting band, and each flow groove (1141) is constructed on the first cutting band.

3. The deep hole drill according to claim 1 or 2, characterized in that: On any of the blades (114), n flow grooves (1141) are arranged at intervals along the axial direction of the drill core (111), and the minimum distance between the groove wall of the flow groove (1141) closest to the drill tip (112) and the cutting edge (113) is I, where I=0.0264*n 2 +0.073*H, wherein H is the width of the land (114).

4. The deep hole drill according to claim 3, characterized in that: On the same edge band (114), the distance between two adjacent flow grooves (1141) increases in a direction away from the drill tip (112).

5. The deep hole drill according to claim 4, characterized in that: The distance between the i-th flow groove (1141) and the i-1-th flow groove (1141) is (0.5+0.25i)H, where i is a natural number not less than 2.

6. The deep hole drill according to claim 1, characterized in that: The flow groove (1141) is a V-shaped groove, and the groove depth of the flow groove (1141) is E, E=0.6mm-0.12mm; and / or the groove wall surface inclination angle of the flow groove (1141) close to the drill tip (112) is F, F=30°-40°.

7. The deep hole drill according to claim 1, characterized in that: The drill core (111) comprises an axial front section and an axial rear section which are continuously arranged along the axial direction thereof, wherein the axial front section is a section of equal diameter, and the axial rear section is a conical section whose diameter gradually decreases along a side away from the drill tip (112), and each of the flow grooves (1141) is formed on each of the blades (114) corresponding to the axial front section.

8. The deep hole drill according to claim 7, characterized in that: The axial length of the equal diameter section is L1, and the diameter is d, L1=2.5D-3D, and / or d=0.25D-0.4D, wherein D is the outer diameter of the drilling section (11).

9. The deep hole drill according to claim 8, characterized in that: The axial length of the inverted cone section is L2, the taper of the inverted cone section is T, and the axial length L2 and the taper T satisfy the following formula:

10. The deep hole drill according to claim 1, characterized in that: The apex angle of the drill tip (112) is A, 137°≤A≤147°, the back angle of the drill tip (112) is B, 9°≤B≤15°, the helix angle of the edge band (114) is C, 27°≤C≤29°; and / or the deep hole drill further comprises a shank section (12) and a clearance section (13) between the shank section (12) and the drilling section (11).

11. The deep hole drill according to claim 10, characterized in that: A=138°,B=8.5°,C=27.5°。

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