Hollow core drill bit

Abstract

The present application relates to a hollow core drill bit, comprising a drill head at a distal end, having a plurality of cutting teeth distributed around a working rotation axis, each cutting tooth comprising a plurality of cutting segments arranged in sequence in an axial direction, the plurality of cutting segments being arranged in sequence in a radial direction towards a radial outer side as arranged in sequence in the axial direction towards a proximal side, thereby forming a stepped structure, the plurality of cutting segments comprising an end segment and one or more circumferential step segments, the end segment being located at a distal most end of the respective cutting tooth in the axial direction and comprising an end cutting edge, the circumferential step segments being located proximally of the end segment in the axial direction. The hollow core drill bit according to the present application can decompose the cutting force during the drilling work, reduce the cutting heat and the deformation of the cutting tooth, and help to split the chips, thereby helping to prolong the service life of the hollow core drill bit.

Description

Technical Field

[0001] This invention relates to the field of cutting tools for cutting operations, and more specifically to a hollow drilling bit. Background Technology

[0002] In industrial production, there are often situations requiring the drilling of large-diameter holes. Using a solid drill bit would subject the drill bit to significant stress and generate substantial cutting heat. To address this issue, a hollow core drill bit can be used. This avoids drilling through the entire volume of material surrounding the hole, requiring only the drilling of a ring-shaped portion. During drilling, the material enclosed by this ring (generally referred to as the "core") falls out. Currently, hollow core drill bits (e.g., plate drills) are widely used in magnetic drill presses, bench drills, and milling machines to cut holes of varying sizes in sheet metal and remove the core material.

[0003] Figure 1 A schematic diagram of a hollow drilling bit 1 in the prior art is shown. Figure 2 It shows Figure 1 The image shows an end view of the hollow drill bit 1 viewed along the axial direction, schematically showing two cutting teeth, namely the first cutting tooth 2 and the second cutting tooth 3, where n represents the rotation direction of the hollow drill bit 1 during operation, and B represents the thickness of the hollow drill bit 1 in the radial direction. Figure 3A and Figure 3B The first cutting tooth 2 and the second cutting tooth 3 are respectively along Figure 2 The view, taken along the AA and BB directions, shows that the main flank face of the first cutting tooth 2 has a segment 4 in the radial plane, and the main flank face of the second cutting tooth 3 has two segments 5 that are angled to each other. The shape of the main flank face of each cutting tooth in the aforementioned radial plane reflects the shape of the corresponding main cutting edge.

[0004] like Figure 3A and Figure 3B As further shown in the diagram, in this design of the hollow drill bit 1, the length of the cutting edge of the cutting teeth in the axial direction (i.e., the length of the cutting edge of the cutting teeth in the axial direction) is... Figure 3A and Figure 3B The Lr (as indicated in the diagram) is often short, which means that during drilling, all cutting teeth participate in the drilling process within a very short time and a small axial range. This results in greater cutting resistance, leading to higher cutting power consumption. Additionally, it also results in a larger chip cross-sectional area, causing difficulty in chip removal and increased cutting heat. This type of hollow drill bit also suffers from problems such as difficulty in positioning and entry during the initial drilling phase, which can easily damage the drill bit and drilling machine. Poor chip removal can also lead to the unfavorable phenomenon of chips being discharged towards the drill core. Furthermore, due to the larger chip cross-sectional area, such as... Figure 4 As shown, when the hole in the workpiece 7 is about to be drilled through, the thinner part to be cut is more likely to be torn apart rather than neatly cut off. This results in a structure 9 with a "brim" shape at the edge of the core 8, making it difficult to drill multiple stacked plate-shaped workpieces 7. Summary of the Invention

[0005] Therefore, the present invention aims to provide a hollow drilling bit that can solve at least one of the technical problems existing in the prior art.

[0006] The present invention relates to a hollow drilling bit, the hollow drilling bit including a drill head located at the distal end of the hollow drilling bit, the drill head having a plurality of cutting teeth distributed around the working rotation axis of the hollow drilling bit, each cutting tooth including a plurality of cutting segments arranged sequentially in the axial direction.

[0007] The plurality of cutting segments are arranged sequentially toward the proximal side in the axial direction and sequentially toward the radially outward side in the radial direction, thereby forming a stepped structure.

[0008] The plurality of cutting segments include an end segment and one or more circumferential step segments. The end segment is located at the farthest end of the corresponding cutting tooth in the axial direction and includes an end cutting edge. The circumferential step segments are positioned in the axial direction near the end segment. Each circumferential step segment extends generally in the circumferential direction and includes a primary cutting edge and a secondary cutting edge.

[0009] The hollow drill bit according to the present invention can decompose the cutting force during drilling, reduce cutting resistance and power, reduce cutting heat and deformation of cutting teeth, and help to divert chips to reduce the area of ​​individual chips, thereby facilitating chip removal, preventing chip jamming, reducing the occurrence of chips flowing towards the core, extending the service life of the hollow drill bit, and improving machining quality. Furthermore, the hollow drill bit according to the present invention can achieve more accurate positioning and easier entry into the workpiece during initial cutting, which reduces the probability of damage and scrap during use. In addition, the hollow drill bit according to the present invention also helps to root cut the core, reducing the brim-like structure at the bottom of the core, thereby enabling continuous drilling through stacked workpieces.

[0010] In some embodiments, the main cutting edge in the circumferential stepped section:

[0011] - It is structured as a single segment, and therefore includes a single main cutting edge segment; or

[0012] - It is configured as a multi-segment and therefore includes multiple main cutting edge segments, wherein an angle is formed between every two adjacent cutting edge segments.

[0013] In some embodiments, one or more of the cutting teeth each include a plurality of circumferential stepped segments, wherein the primary and secondary cutting edges of the plurality of circumferential stepped segments are oriented and sized to be identical to each other.

[0014] In some embodiments, one or more of the cutting teeth each include a plurality of circumferential stepped segments, the plurality of circumferential stepped segments satisfying one or more of the following:

[0015] Each circumferential step section has a main cutting edge that is a single segment, and the orientation and / or size of each main cutting edge are at least partially different from each other;

[0016] The number of segments of the main cutting edge in each circumferential step section is at least partially different from each other;

[0017] The orientation and / or dimensions of the secondary cutting edges of each circumferential step segment are at least partially different from each other.

[0018] In some embodiments, the end cutting edge and the main cutting edge of each circumferential step section are both configured as a single piece, and the inclination angle of the end cutting edge and the inclination angle of the main cutting edge of each circumferential step section are respectively between -30° and +30°.

[0019] In some embodiments, in the axial plane, the radial thickness of the end section and the radial thickness of each circumferential step section are respectively one-half to one-fifth of the radial wall thickness of the hollow drill bit; and / or,

[0020] The thickness of the end section in the radial direction and the thickness of each circumferential step section in the radial direction are added together to equal the wall thickness of the hollow drill bit in the radial direction.

[0021] In some embodiments, the end cutting edge:

[0022] - It is structured as a single segment, and therefore includes a single cutting edge segment; or

[0023] - It is configured as a multi-segment and therefore includes multiple cutting edge segments, wherein an angle is formed between every two adjacent cutting edge segments.

[0024] In some embodiments, in the axial plane, the radial thickness of the end segment is equal to or at least partially unequal to the radial thickness of the respective circumferential step segments; and / or

[0025] The end cutting edge and the main cutting edge of each circumferential step section are all configured as a single piece, and the inclination angle of the end cutting edge is equal to or at least partially unequal to the inclination angle of the main cutting edge in each circumferential step section.

[0026] In some embodiments, in the axial direction, the total length of the plurality of cutting segments of each cutting tooth is not less than half the depth of the groove between the cutting tooth and any adjacent cutting tooth.

[0027] In some embodiments, at least two of the plurality of cutting teeth have the same tooth profile.

[0028] In some embodiments, at least two of the plurality of cutting teeth have different tooth profiles and satisfy one or more of the following:

[0029] The at least two cutting teeth have end sections with different structures;

[0030] The at least two cutting teeth have different numbers of circumferential stepped sections;

[0031] The primary and secondary cutting edges of the at least two cutting teeth, starting from the circumferential step section at the farthest side in the axial direction, are at least partially different from each other in size and orientation.

[0032] In some embodiments, the at least two cutting teeth have end segments with different configurations and satisfy one or more of the following:

[0033] The number of cutting edge segments varies at each end of the cutting edge.

[0034] The principal cutting edge angle of the innermost section of the cutting edge at each end is different in the radial direction;

[0035] Each end cutting edge is a single segment, and the length and / or inclination angle of each end cutting edge are different.

[0036] In some embodiments, the at least two cutting teeth have different numbers of circumferential step segments, and the primary and secondary cutting edges of the circumferential step segments of the at least two cutting teeth, starting from the circumferential step segment furthest in the axial direction, have the same orientation and size.

[0037] In some embodiments, the circumferential step segments of the at least two cutting teeth, starting from the circumferential step segment furthest in the axial direction, satisfy one or more of the following:

[0038] The main cutting edge of each circumferential step segment is constructed as a single segment, and the orientation and / or size of the main cutting edge of each circumferential step segment are different from each other;

[0039] The main cutting edge of each circumferential step section is constructed as a single segment, and the cutting edge inclination angle of the main cutting edge of each circumferential step section is different;

[0040] The number of segments of the main cutting edge varies in each circumferential step section;

[0041] The orientation and / or size of the secondary cutting edges differ in each circumferential step section.

[0042] In some embodiments, the at least two cutting teeth satisfy one or both of the following conditions:

[0043] The distal ends in the axial direction are located at different axial positions;

[0044] The inner ends in the radial direction are located at different radial positions.

[0045] In some embodiments, the at least two cutting teeth are arranged adjacent to each other in the circumferential direction, the at least two cutting teeth constitute a cutting tooth group, and the hollow drilling bit includes a plurality of the cutting tooth groups arranged sequentially in the circumferential direction.

[0046] In some embodiments, the at least two cutting teeth include a first cutting tooth and a second cutting tooth, the first cutting tooth including a circumferential stepped section and the second cutting tooth including two circumferential stepped sections.

[0047] In some embodiments, the plurality of cutting teeth are evenly spaced around the working rotation axis of the hollow drill bit.

[0048] The technical features mentioned above, those to be mentioned below, and those shown individually in the accompanying drawings can be combined arbitrarily, provided that the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described herein. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features. Attached Figure Description

[0049] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0050] Figure 1 A perspective view of a prior art hollow drilling bit is shown.

[0051] Figure 2 It shows Figure 1The diagram shows the end view of the hollow drill bit viewed along the axial direction, with the positions of the first and second cutting teeth marked.

[0052] Figure 3A and Figure 3B The following are shown respectively along Figure 2 The view observed in the AA and BB directions.

[0053] Figure 4 The diagram shows a workpiece being machined using some existing hollow drill bits and a core cut off by a sleeve.

[0054] Figure 5 A perspective view of a hollow drilling bit according to some embodiments of the present invention is shown.

[0055] Figure 6 It shows Figure 5 The diagram shows an end view of the hollow drill bit viewed along the axial direction, with exemplary positions of the first and second cutting teeth marked.

[0056] Figure 7A It shows Figure 5 A side view of a hollow drill bit, showing the position of the first cutting tooth.

[0057] Figure 7B It shows Figure 7A A magnified three-dimensional view of the first cutting tooth.

[0058] Figure 7C A first cutting tooth edge is shown according to some embodiments of the present invention. Figure 6 The view viewed from the MM direction.

[0059] Figure 7D It shows along Figure 5 The end view of the first cutting tooth in the axial plane according to some embodiments of the present invention when viewed in the axial direction of the hollow drill bit.

[0060] Figure 8A It shows Figure 5 A side view of a hollow drill bit, showing the position of the second cutting tooth.

[0061] Figure 8B It shows Figure 8A An enlarged 3D view of the second cutting tooth.

[0062] Figure 8C A second cutting tooth edge is shown according to some embodiments of the present invention. Figure 6 The view viewed from the QQ direction.

[0063] Figure 8D It shows along Figure 5 The end view of the second cutting tooth in the axial plane according to some embodiments of the present invention when viewed in the axial direction of the hollow drill bit.

[0064] Figure 9 It shows the use of Figure 5 A schematic diagram of the workpiece being processed by the hollow drilling bit and the core material cut off by the sleeve.

[0065] Figure 10 A perspective view of a hollow drilling bit according to other embodiments of the present invention is shown.

[0066] Figure 11A and Figure 11B A perspective view of the drill head of a hollow drilling bit according to other embodiments of the present invention is shown.

[0067] Figure 12 A perspective view of a hollow drilling bit according to yet another embodiment of the present invention is shown. Detailed Implementation

[0068] The following describes various illustrative embodiments of the present invention. In this specification, various systems, structures, and devices are schematically depicted in the accompanying drawings for illustrative purposes only, and not all features of actual systems, structures, and devices are described. For example, well-known functions or structures are not described in detail to avoid unnecessary detail that could obscure the invention. It should be understood that in any practical application, many specific implementation decisions need to be made to achieve the specific goals of the developer or user, and to comply with system-related and industry-related limitations, which may vary depending on the specific application. Furthermore, it should be understood that while such implementation decisions are complex and time-consuming, they are routine tasks for those skilled in the art who benefit from this application.

[0069] The terms and phrases used herein should be understood and interpreted in accordance with the understanding of those skilled in the art. The consistent use of terms or phrases herein is not intended to imply a specific definition, i.e., a definition different from the common and conventional meaning understood by those skilled in the art. For terms or phrases intended to have a specific meaning, i.e., a meaning different from that understood by those skilled in the art, such specific definition will be explicitly listed in the specification, giving the specific definition of the term or phrase directly and unambiguously.

[0070] Unless otherwise required by the content, throughout the following description, the word “including” and its variations, such as “contains”, will be interpreted in an open-ended, inclusive sense, that is, as “including but not limited to”.

[0071] Throughout this specification, references to terms such as "an embodiment," "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. Therefore, the phrases "in one embodiment" or "in one embodiment" appearing in different places throughout this specification do not necessarily refer to the same embodiment. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0072] Furthermore, the terms "first," "second," etc., 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 with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0073] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0074] In the following description with reference to the accompanying drawings, the same reference numerals refer to similar or identical elements throughout the drawings and their description. Furthermore, the various features in the drawings discussed below are not necessarily drawn to scale. The dimensions of the various features and elements in the drawings may be enlarged or reduced to more clearly illustrate embodiments of the invention. For supplementary aspects of the teachings that can be directly identified from the drawings, see the relevant prior art. It should be noted that various modifications and variations in the form and detail of the embodiments can be implemented without departing from the overall concept of the invention.

[0075] Hereinafter, some embodiments of the hollow drilling bit of the present invention will be described in detail based on the accompanying drawings. In this specification, unless otherwise specified, the direction around the working rotation axis of the hollow drilling bit during rotary drilling is the axial direction, the rotation direction of each cutting tooth of the hollow drilling bit during rotary drilling is the circumferential direction, the direction perpendicular to the axial direction of the hollow drilling bit is the radial direction, the plane passing through the aforementioned rotation axis is the radial plane, and the plane perpendicular to the aforementioned rotation axis is the axial plane. Furthermore, for ease of description, the side of the hollow drilling bit closer to the workpiece can be defined as the far side, and the side farther from the workpiece (i.e., the side closer to the operator) can be defined as the near side.

[0076] like Figure 5 As shown, a hollow drilling bit 10 according to some embodiments of the present invention may include a drill head 11 located at a distal end and a shank 12 positioned proximal to the drill head 11, the drill head 11 and the shank 12 being integrally formed. The drill head 11 may include a plurality of cutting teeth 13 distributed around a rotation axis, each cutting tooth 13 being used to cooperate in drilling on the workpiece to remove annular material portions and cut out cylindrical cores. Advantageously, the cutting teeth 13 may be arranged to be evenly spaced around the working rotation axis of the hollow drilling bit 10 to help balance the forces on the hollow drilling bit 10 during drilling operations, thereby helping to extend the life of the hollow drilling bit 10.

[0077] like Figure 5 As shown, each cutting tooth 13 may include a plurality of cutting segments 14 arranged sequentially in the axial direction. These cutting segments 14 may be arranged sequentially towards the proximal side in the axial direction and towards the radially outward side in the radial direction to form a stepped structure. These cutting segments 14 may extend in the circumferential direction between the proximal and distal ends. The plurality of cutting segments 14 forming a stepped structure increases the total length of each cutting segment 14 in the axial direction, and the cutting tooth 13 can cut into the workpiece step by step, thereby effectively decomposing and dispersing the cutting force on the cutting tooth 13. Accordingly, this helps to dissipate cutting heat and reduce the chip area, thereby facilitating smooth chip removal and reducing the formation of built-up edge, and extending the life of the hollow drill bit 10.

[0078] Furthermore, since the cutting portion 14 of the cutting tooth 13 that initially contacts and cuts into the workpiece has a smaller radial dimension, it helps to drill the hollow drill bit 10 into the workpiece and achieve more accurate positioning, reducing relative wobble between the hollow drill bit 10 and the workpiece, and improving machining accuracy and quality. Similarly, when the hole in the workpiece is about to be machined, since the cutting portion 14 of the cutting tooth 13 that last contacts and cuts into the workpiece has a smaller radial dimension, it helps to reduce relative wobble between the hollow drill bit 10 and the workpiece, thereby reducing or avoiding the formation of a "brim" structure when there is a harder object supporting the lower surface of the workpiece. For example, as Figure 9 As shown, this allows the hollow drill bit 10 to be used to process two or more workpieces 7' stacked together, and to form a smaller “brim” structure 9' only below the core 8' cut from the bottommost workpiece 7', or even not to form a “brim” structure 9' at all.

[0079] The cutting section 14 may include an end section 15 located at its farthest end in the axial direction, and a circumferential stepped section 16 positioned proximal to the end section 15 in the axial direction. For example... Figure 5 As shown, each circumferential step segment 16 can be configured to extend generally along the circumferential direction.

[0080] Below, in conjunction with Figures 7A to 7D as well as Figures 8A to 8D The first cutting tooth 20 and the second cutting tooth 30 of the hollow drilling bit 10 according to some embodiments of the present invention will be further described. The first cutting tooth 20 and the second cutting tooth 30 can, for example, be positioned in the circumferential direction at... Figure 6 At the location shown.

[0081] like Figure 7A As shown, the hollow drilling bit 10 may include a first cutting tooth 20. (As indicated...) Figure 7B As shown, the first cutting tooth 20 may include an end section 21 and a plurality of circumferential stepped sections 22. The end section 21 may include an end cutting edge 28, and each circumferential stepped section 22 includes a main cutting edge 23 and a secondary cutting edge 24.

[0082] like Figure 7BAs shown, the end cutting edge 28 of the first cutting tooth 20 can be configured as a single segment, and therefore includes a single cutting edge segment. The main cutting edge 23 of each circumferential step segment 22 of the first cutting tooth 20 can also be configured as a single segment, and therefore includes a single main cutting edge segment. In other embodiments, the end cutting edge 28 of the first cutting tooth 20 can also be configured as multi-segmented, and therefore includes multiple cutting edge segments, wherein adjacent cutting edge segments of the multiple cutting edge segments form an angle. In other embodiments not shown, the main cutting edge 23 of each circumferential step segment 22 of the first cutting tooth 20 can also be configured as multi-segmented, and therefore includes multiple main cutting edge segments, wherein adjacent cutting edge segments of the multiple main cutting edge segments form an angle.

[0083] Figure 7C The first cutting tooth 20 according to some embodiments of the present invention is shown along... Figure 6 The view viewed from the MM direction. For example... Figure 7C As shown, the orientation and dimensions of the main cutting edge 23 and the secondary cutting edge 24 of each circumferential step section 22 of the first cutting tooth 20 can be configured to be identical to each other to facilitate machining and manufacturing, and to contribute to uniform heat generation during drilling. For example, as Figure 7C As shown, the axial heights h11, h12, h13, and h14 of the main cutting edges 23 of each circumferential stepped section 22 of the first cutting tooth 20 can be set to be the same, and the axial heights h21, h22, h23, and h24 of the secondary cutting edges 24 can be set to be the same. Furthermore, each main cutting edge 23 can have the same orientation, and each secondary cutting edge 24 can have the same orientation. Advantageously, the sum of the axial heights Lr1 of all cutting sections of the first cutting tooth 20 (i.e., including the end section 21 and the plurality of circumferential stepped sections 22) is set not less than the depth L0 of the groove between the first cutting tooth 20 and any adjacent cutting tooth (e.g., in...). Figure 7A (as shown in the diagram) half of the total height Lr1. For example, the sum of the heights Lr1 mentioned above can be set to 60%, 80%, 90%, etc., of the depth L0.

[0084] In other embodiments not shown, the dimensions and orientations of the primary cutting edges 23 and secondary cutting edges 24 of the respective circumferential step segments 22 of the first cutting tooth 20 can be at least partially different from each other to accommodate various drilling requirements. For example, the primary cutting edges 23 of each circumferential step segment 22 of the first cutting tooth 20 can all be configured as a single segment, and the orientations and / or dimensions of the respective primary cutting edges 23 can be set to be at least partially different from each other. For example, the number of segments of the primary cutting edges 23 of the respective circumferential step segments 22 of the first cutting tooth 20 can be set to be at least partially different from each other. For example, the orientations and / or dimensions of the secondary cutting edges 24 of the respective circumferential step segments 22 of the first cutting tooth 20 can be set to be at least partially different from each other.

[0085] Figure 7D It shows along Figure 5 Viewed axially from the hollow drilling bit 10, this is an end view of the first cutting tooth 20 according to some embodiments of the invention, schematically showing the rake angle β1 of the end cutting edge 28 and the rake angles β11, β1i, β1n of some of the main cutting edges 23 of the circumferential step section 22. Here, i can be equal to 1, 2, 3...n, and represents the order of the various circumferential step sections starting from the farthest circumferential step section. Position "O" is the location of the working rotation axis of the hollow drilling bit 10. Advantageously, the aforementioned rake angles can be set between -30° and 30°. In some embodiments, the rake angle β1 of the end cutting edge 28 may be set to be equal to one or more of the rake angles β11…β1i…β1n of the main cutting edges 23 of each circumferential step segment 22, or it may be set to be unequal to any of the rake angles β11…β1i…β1n of the main cutting edges 23 of each circumferential step segment 22. The rake angles β11…β1i…β1n of each main cutting edge 23 may be set to be equal to each other, or at least partially unequal to each other.

[0086] Figure 7DFurther illustration shows the radial thickness b1 of the end section 21 and the radial thicknesses b11, b12, b1i, and b1n of the plurality of circumferential stepped sections 22 in the projection onto the axial plane. Advantageously, the sum of the radial thickness b1 of the end section 21 and the radial thicknesses b11, b12, b1i, and b1n of the plurality of circumferential stepped sections 22 is equal to the radial wall thickness B of the hollow drill bit 10. The aforementioned radial thicknesses can be set to be between one-half and one-fifth of the radial wall thickness B of the hollow drill bit 10. Advantageously, in some embodiments, the radial thickness b1 of the end segment 21 can be set to be equal to one or more of the radial thicknesses b11, b12...b1i...b1n of each circumferential step segment 22, or it can be set to be unequal to any of the radial thicknesses b11, b12...b1i...b1n of each circumferential step segment 22. The radial thicknesses b11, b12...b1i...b1n of each circumferential step segment 22 can be set to be equal to each other, or at least partially unequal to each other.

[0087] Figures 8A to 8D The image shown is the second cutting tooth 30 of a hollow drilling bit 10 according to some embodiments of the present invention. For example, as... Figures 8A to 8B As shown, the construction of the second cutting tooth 30 can be substantially the same as that of the first cutting tooth 20, and the main difference between the second cutting tooth 30 and the first cutting tooth 20 is that the end cutting edge 38 of the end segment 31 of the second cutting tooth 30 can be configured as a two-segment, and therefore can include two cutting edge segments, wherein these two cutting edge segments form a certain angle. Furthermore, in Figure 8B The diagram schematically shows the corresponding circumferential step section 32 of the second cutting tooth 30, and the corresponding main cutting edge 33 and secondary cutting edge 34 of the circumferential step section 32.

[0088] It should be understood that, in addition to the first cutting tooth 20 and the second cutting tooth 30 described above, the hollow drilling bit 10 according to the present invention may also include cutting teeth 13 of one or more other shapes, which will not be described in detail here.

[0089] In such Figure 5In the hollow drill bit 10 shown, at least two of the plurality of cutting teeth 13 can be arranged such that their farthest ends in the axial direction are located at different axial positions. When such a hollow drill bit 10 is drilling, the cutting teeth 13 located at different axial positions do not contact the workpiece simultaneously, but rather contact the workpiece sequentially and begin drilling. This helps to disperse cutting forces and reduce cutting heat, thereby helping to reduce deformation of the cutting teeth 13 and extend the life of the hollow drill bit 10. The aforementioned at least two cutting teeth 13 can be arranged adjacent to each other in the circumferential direction. More advantageously, the aforementioned at least two cutting teeth 13 arranged adjacent to each other constitute a cutting tooth group, and the hollow drill bit 10 can include multiple cutting tooth groups arranged sequentially in the circumferential direction. This helps to balance the forces during the rotation of the hollow drill bit 10, thereby further extending the life of the hollow drill bit 10.

[0090] In other embodiments, the at least two cutting teeth 13 described above may alternatively or further be arranged such that their innermost ends are located at different radial positions in the radial direction. Such a hollow drill bit 10, during drilling, can simultaneously remove material from different locations on the workpiece, which helps improve drilling efficiency, disperses cutting forces, and reduces cutting heat, thereby helping to reduce deformation of the cutting teeth 13 and extend the life of the hollow drill bit 10.

[0091] As described above, at least two cutting teeth 13 of the hollow drilling bit 10 according to an embodiment of the present invention can be configured to be misaligned relative to each other in one or both of the axial and radial directions. This helps to reduce or avoid periodic vibrations generated by the hollow drilling bit 10 during drilling, resulting in a smoother drilling process, thereby contributing to improved machining accuracy and surface finish. Furthermore, this also helps to disperse cutting forces, reduce cutting heat, and reduce deformation of the cutting teeth 13, thereby extending the life of the hollow drilling bit 10.

[0092] The at least two cutting teeth 13 described above may have the same tooth profile to facilitate machining. Alternatively, the at least two cutting teeth 13 described above may also have different tooth profiles to help accommodate various drilling requirements, such as helping to further disperse cutting forces and reduce cutting heat.

[0093] For example, the end segments 15 of each cutting tooth 13 may have different configurations. For example, in the first cutting tooth 20 and the second cutting tooth 30 described above, the number of cutting edge segments of the end cutting edge 28 of the end segment 21 of the first cutting tooth 20 and the end cutting edge 38 of the end segment 31 of the second cutting tooth 30 are different. In addition, the principal cutting edge angle of the innermost cutting edge segment of the end segment 15 of each cutting tooth 13 in the radial direction can be set to be different from each other. For example, Figure 7C The diagram shows the principal cutting edge angle λ1 of the end cutting edge 28 of the end segment 21 of the first cutting tooth 20 according to some embodiments of the present invention, located at the innermost end of the cutting edge segment in the radial direction. Figure 8C The diagram shows the principal cutting edge angle λ2 of the end cutting edge 38 of the end segment 31 of the second cutting tooth 30 according to some embodiments of the present invention, located at the innermost end of the cutting edge segment in the radial direction. The principal cutting edge angles λ1 and λ2 may be unequal. For example, when the end cutting edges of the end segments 15 of each cutting tooth 13 are all configured as a single piece, the lengths of the respective end cutting edges may be set to be different from each other.

[0094] However, it should be understood that the end segments 15 of each of the aforementioned cutting teeth 13 may be identical in one or more aspects of the number of segments of the cutting edge section, the principal cutting edge angle of the cutting edge section located at the innermost end in the radial direction, and the length of the end cutting edge of each end segment 15 when the end cutting edge of each cutting tooth 13 is configured as a single segment.

[0095] For example, the individual cutting teeth 13 may have different numbers of circumferential step segments 16, and the dimensions and orientations of the primary and secondary cutting edges of the same sequence of circumferential step segments 16, starting from the farthest circumferential step segment 16 in the axial direction, may be at least partially different from each other. For example, for each of the same sequence of circumferential step segments 16, the primary cutting edge of each circumferential step segment 16 may be constructed as a single segment, and the orientation and / or dimensions of the primary cutting edges of each circumferential step segment 16 may be at least partially different from each other. As another example, for each of the same sequence of circumferential step segments 16, the number of segments of the primary cutting edges of each circumferential step segment 16 may be set to be at least partially different from each other. As another example, for each of the same sequence of circumferential step segments 16, the orientation and / or dimensions of the secondary cutting edges of each circumferential step segment 16 may be set to be at least partially different from each other. For example, for each circumferential step segment 16 of the same sequence, the main cutting edge of each circumferential step segment 16 can be constructed as a single piece, and the main cutting edge of each circumferential step segment 16 can have a different cutting edge inclination angle.

[0096] However, it should be understood that the aforementioned cutting teeth 13 may be identical to each other in one or more of the following aspects: the number of circumferential step segments 16, the number of main cutting edges of the same sequence of circumferential step segments 16 starting from the farthest circumferential step segment 16 in the axial direction, the orientation and / or size of the main cutting edges of the respective circumferential step segments 16 when the main cutting edges are configured as a single segment, the orientation and / or size of the secondary cutting edges, and the rake angle of the main cutting edges of the respective circumferential step segments 16 when the main cutting edges are configured as a single segment.

[0097] For example, such as Figure 7C and Figure 8C As shown, the height h11 of the main cutting edge 23 of the first circumferential step section 22 at the farthest side in the axial direction of the first cutting tooth 20 and the height h31 of the main cutting edge 33 of the first circumferential step section 32 at the farthest side in the axial direction of the second cutting tooth 20 can be equal or unequal. Similarly, the heights h12, h13...h1i, h1n of the main cutting edges 23 of the second, third...i, n circumferential step sections 22 at the farthest side in the axial direction of the first cutting tooth 20 and the heights h32, h33...h3i, h3n of the main cutting edges 33 of the corresponding second, third...i, n circumferential step sections 32 at the farthest side in the axial direction of the second cutting tooth 30 can be equal or unequal.

[0098] For example, such as Figure 7C and Figure 8C As shown, the height h21 of the secondary cutting edge 24 of the first circumferential step section 22 at the farthest point in the axial direction of the first cutting tooth 20 and the height h41 of the secondary cutting edge 34 of the first circumferential step section 32 at the farthest point in the axial direction of the second cutting tooth 30 can be equal or unequal. Similarly, the heights h22, h23...h2i, h2n of the secondary cutting edges 24 of the second, third...i, n circumferential step sections 22 at the farthest point in the axial direction of the first cutting tooth 20 and the heights h42, h43...h4i, h4n of the corresponding secondary cutting edges 34 of the second, third...i, n circumferential step sections 32 at the farthest point in the axial direction of the second cutting tooth 30 can be equal or unequal.

[0099] For example, such as Figure 7D and Figure 8DAs shown, the rake angle β1 of the end cutting edge 28 of the first cutting tooth 20 and the rake angle β2 of the end cutting edge 38 of the second cutting tooth 30 can be equal or unequal. For example, the rake angles β11...β1i, β1n of each main cutting edge 23 of the first cutting tooth 20 starting from the first circumferential step section 22 at the farthest end in the axial direction and the corresponding rake angles β21...β2i, β2n of each main cutting edge 33 of the second cutting tooth 30 starting from the first circumferential step section 32 at the farthest end in the axial direction can be equal or unequal.

[0100] For example, Figure 10 A hollow drilling bit 10' according to some embodiments of the present invention is shown. As shown, the first cutting teeth 50 and the second cutting teeth 60 arranged adjacent to each other in the hollow drilling bit 10' can form a cutting tooth group 70, and the hollow drilling bit 10' can include a plurality of cutting tooth groups 70 arranged sequentially in the circumferential direction. For example, the hollow drilling bit 10' can include three consecutive cutting tooth groups 70. The size and orientation of the main cutting edge and the secondary cutting edge of the same sequence of circumferential step sections of the first cutting tooth 50 and the second cutting tooth 60, starting from the circumferential step section at the farthest side in the axial direction, can be at least partially different from each other. For example, the aforementioned circumferential step sections of the same sequence can have main cutting edges and secondary cutting edges of different lengths. The first cutting tooth 50 and the second cutting tooth 60 can also have different numbers of circumferential step sections, for example, as Figure 10 As shown, the first cutting tooth 50 may have one circumferential stepped section, while the second cutting tooth 60 may have two circumferential stepped sections. Optionally, the farthest ends of the first cutting tooth 50 and the second cutting tooth 60 in the axial direction may be located at different axial positions. Optionally, the innermost ends of the first cutting tooth 50 and the second cutting tooth 60 in the radial direction may be located at different radial positions. With this configuration, during drilling, the cutting edges of each circumferential stepped section of each cutting tooth only need to handle a portion of the cutting, thereby decomposing the cutting force, diverting the chips, reducing the cutting resistance of each cutting tooth, and lowering cutting heat. Furthermore, this configuration of the hollow drilling bit 10' also helps to reduce the chip area, making chip removal easier, resulting in a smoother cutting process and extending the life of the hollow drilling bit 10'.

[0101] Although Figure 5 The diagram shows an integrally formed drill head 11 and shank 12, but in other embodiments, the hollow drilling bit 10 may also include a separately formed drill head and shank, and the drill head and shank may be detachably connected together. For example, Figure 11A and Figure 11BThe image shows a drill head 11' for attachment to the corresponding shank (not shown).

[0102] In such Figure 5 In the illustrated embodiment, the drill head 11 of the hollow drilling bit 10 can be integrally made of the same material. In other embodiments, for example, in... Figure 12 In the illustrated embodiment, the drill head 11 of the hollow drilling bit 10 may also include a base portion 18 and a hard material portion 19 welded to the base portion 18 at the surface of each cutting tooth 13 facing the workpiece. The hard material portion 19 may be made of, for example, cemented carbide.

[0103] As described above, the hollow drill bit 10 according to some embodiments of the present invention can decompose the cutting force during drilling, reduce cutting resistance and power, reduce cutting heat and deformation of cutting teeth, and help to divert chips to reduce the area of ​​individual chips, thereby facilitating chip removal, preventing chip jamming, and reducing the occurrence of chips flowing towards the core, thus helping to extend the service life of the hollow drill bit 10 and improve machining quality. Furthermore, the hollow drill bit 10 according to embodiments of the present invention can achieve more accurate positioning and easier entry into the workpiece during initial cutting, which reduces the probability of damage and scrapping during use. The hollow drill bit 10 according to some embodiments of the present invention also helps to reduce or avoid periodic vibrations generated during drilling, making the drilling process smoother and improving machining accuracy and flatness. In addition, the hollow drill bit 10 according to the present invention also helps to root cut the core, reducing the brim-like structure at the bottom of the core, thereby enabling continuous drilling through stacked workpieces.

[0104] This invention may include any feature or combination of features or generalization thereof implied or expressly disclosed herein, and is not limited to any of the defined scopes listed above. Any elements, features and / or structural arrangements described herein may be combined in any suitable manner.

[0105] The specific embodiments disclosed above are merely exemplary, and it will be apparent to those skilled in the art, who benefit from the teachings herein, that the invention can be modified and implemented in different but equivalent ways. Therefore, it is obvious that changes and modifications can be made to the specific embodiments disclosed above, and all such variations are considered to fall within the scope and spirit of the invention.

Claims

1. A hollow drilling bit, characterized in that, The hollow drilling bit includes a drill head located at the distal end of the hollow drilling bit, the drill head having a plurality of cutting teeth distributed around the working rotation axis of the hollow drilling bit, each cutting tooth including a plurality of cutting segments arranged sequentially in the axial direction. The plurality of cutting segments are arranged sequentially toward the proximal side in the axial direction and sequentially toward the radially outward side in the radial direction, thereby forming a stepped structure. The plurality of cutting sections includes an end section and one or more circumferential stepped sections. The end section is located at the farthest end of the corresponding cutting tooth in the axial direction and includes an end cutting edge. The circumferential stepped sections are positioned axially proximal to the end section. Each circumferential stepped section extends generally in the circumferential direction and includes a primary cutting edge and a secondary cutting edge. Furthermore, in the axial direction, the total length of the plurality of cutting segments is not less than half the depth of the groove between the cutting tooth and any adjacent cutting tooth.

2. The hollow drilling bit according to claim 1, characterized in that, The main cutting edge in the circumferential stepped section: - It is structured as a single segment, and therefore includes a single main cutting edge segment; or - It is configured as a multi-segment and therefore includes multiple main cutting edge segments, wherein an angle is formed between every two adjacent cutting edge segments.

3. The hollow drilling bit according to claim 1, characterized in that, One or more of the cutting teeth each include a plurality of circumferential stepped sections, wherein the main cutting edge and the secondary cutting edge of the plurality of circumferential stepped sections have the same orientation and size.

4. The hollow drilling bit according to claim 1, characterized in that, One or more of the cutting teeth each include a plurality of circumferential stepped segments, wherein the plurality of circumferential stepped segments satisfy one or more of the following: Each circumferential step section has a main cutting edge that is a single segment, and the orientation and / or size of each main cutting edge are at least partially different from each other; The number of segments of the main cutting edge in each circumferential step section is at least partially different from each other; The orientation and / or dimensions of the secondary cutting edges of each circumferential step segment are at least partially different from each other.

5. The hollow drilling bit according to any one of claims 1 to 4, characterized in that, The end cutting edge and the main cutting edge of each circumferential step section are all composed of a single piece, and the inclination angle of the end cutting edge and the inclination angle of the main cutting edge of each circumferential step section are respectively between -30° and +30°.

6. The hollow drilling bit according to any one of claims 1 to 4, characterized in that, In the axial plane, the radial thickness of the end section and the radial thickness of each circumferential step section are respectively one-half to one-fifth of the radial wall thickness of the hollow drill bit; and / or, The thickness of the end section in the radial direction and the thickness of each circumferential step section in the radial direction are added together to equal the wall thickness of the hollow drill bit in the radial direction.

7. The hollow drilling bit according to any one of claims 1 to 4, characterized in that, The end cutting edge: - It is structured as a single segment, and therefore includes a single cutting edge segment; or - It is configured as a multi-segment and therefore includes multiple cutting edge segments, wherein an angle is formed between every two adjacent cutting edge segments.

8. The hollow drilling bit according to any one of claims 1 to 4, characterized in that, In the axial plane, the radial thickness of the end segment is equal to or at least partially unequal to the radial thickness of each circumferential step segment; and / or The end cutting edge and the main cutting edge of each circumferential step section are all configured as a single piece, and the inclination angle of the end cutting edge is equal to or at least partially unequal to the inclination angle of the main cutting edge in each circumferential step section.

9. The hollow drilling bit according to any one of claims 1 to 4, characterized in that, In the axial direction, the total length of the plurality of cutting segments is not less than 80% of the depth of the groove between the cutting tooth and any adjacent cutting tooth.

10. The hollow drilling bit according to claim 1, characterized in that, At least two of the plurality of cutting teeth have the same tooth profile.

11. The hollow drilling bit according to claim 1, characterized in that, At least two of the plurality of cutting teeth have different tooth profiles and satisfy one or more of the following: The at least two cutting teeth have end sections with different structures; The at least two cutting teeth have different numbers of circumferential stepped sections; The orientation and size of the primary and secondary cutting edges of the at least two cutting teeth, starting from the circumferential step section at the farthest side in the axial direction, are at least partially different from each other.

12. The hollow drilling bit according to claim 11, characterized in that, The at least two cutting teeth have end segments with different configurations and satisfy one or more of the following: The number of cutting edge segments varies at each end of the cutting edge. The principal cutting edge angle of the innermost section of the cutting edge at each end is different in the radial direction; Each end cutting edge is a single segment, and the length and / or inclination angle of each end cutting edge are different.

13. The hollow drilling bit according to claim 11, characterized in that, The at least two cutting teeth have different numbers of circumferential step segments, and the main cutting edges and secondary cutting edges of the at least two cutting teeth in the same order, starting from the circumferential step segment furthest in the axial direction, are oriented and sized to be the same.

14. The hollow drilling bit according to claim 11, characterized in that, The circumferential step segments of the at least two cutting teeth, each in the same order starting from the circumferential step segment furthest in the axial direction, satisfy one or more of the following: The main cutting edge of each circumferential step segment is constructed as a single segment, and the orientation and / or size of the main cutting edge of each circumferential step segment are different from each other; The main cutting edge of each circumferential step section is constructed as a single segment, and the cutting edge inclination angle of the main cutting edge of each circumferential step section is different; The number of segments of the main cutting edge varies in each circumferential step section; The orientation and / or size of the secondary cutting edges differ in each circumferential step section.

15. The hollow drilling bit according to any one of claims 10 to 14, characterized in that, The at least two cutting teeth satisfy one or both of the following conditions: The distal ends in the axial direction are located at different axial positions; The inner ends in the radial direction are located at different radial positions.

16. The hollow drilling bit according to claim 15, characterized in that, The at least two cutting teeth are arranged adjacent to each other in the circumferential direction, the at least two cutting teeth constitute a cutting tooth group, and the hollow drilling bit includes a plurality of the cutting tooth groups arranged sequentially in the circumferential direction.

17. The hollow drilling bit according to claim 16, characterized in that, The at least two cutting teeth include a first cutting tooth and a second cutting tooth, the first cutting tooth including a circumferential stepped section, and the second cutting tooth including two circumferential stepped sections.

18. The hollow drilling bit according to any one of claims 1 to 4, characterized in that, The plurality of cutting teeth are evenly spaced around the working rotation axis of the hollow drill bit.

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