Cutting screw tap capable of continuously keeping finish degree of machining surface

Abstract

The utility model provides a cutting screw tap capable of continuously keeping the finish degree of a machining surface, which comprises a handle part and a cutting part which are connected with each other, and the cutting part comprises a spiral cutting edge group; the cutting knife group comprises a first cutting unit and a second cutting unit; the first cutting units and the second cutting units are the same in number and are evenly arranged in the circumferential direction of the cutting part in a staggered mode. The first cutting unit comprises a first cutting edge and a first correction edge which are sequentially arranged in the direction from the cutting part to the handle part, the second cutting unit comprises a second cutting edge and a second correction edge which are sequentially arranged in the direction from the cutting part to the handle part, and the first correction edge and the second correction edge are different in height in the radial direction of the screw tap. The cutting screw tap capable of continuously keeping the smooth finish of the machining surface is simple and ingenious in structural design, the overall service life of the cutting screw tap can be effectively prolonged, and meanwhile cutting resistance can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of tap tools, and more specifically, to a cutting tap that can continuously maintain the smoothness of the machining surface. Background Art

[0002] Traditional cutting taps all include a shank and a cutting part, and the cutting part includes a cutting edge and a finishing edge; the cutting edge includes a plurality of cutting pieces, and the finishing edge includes a plurality of finishing edges. The diameter of each cutting piece gradually increases in the direction from the cutting part to the shank. During cutting, drilling is performed through the cutting pieces, and then the subsequent tooth holes are cut to the same radius through the finishing edge to achieve the tapping process.

[0003] However, the core problem is that the heights of all the finishing edges in the radial direction are equal. This leads to all the finishing edges being worn simultaneously during cutting. On the one hand, it will greatly reduce the overall service life of the finishing edges. Once they are worn simultaneously to the point where they cannot meet the machining accuracy, the smoothness of the machining surface cannot be maintained, and they can only be scrapped. On the other hand, due to all the finishing edges being worn simultaneously, the resistance during the machining process is relatively large, resulting in greater energy consumption.

[0004] In view of this, the applicant has proposed a cutting tap that can continuously maintain the smoothness of the machining surface, with a simple and ingenious structural design, which can effectively improve the overall service life of the cutting tap while reducing the resistance during cutting. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a cutting tap that can continuously maintain the smoothness of the machining surface, with a simple and ingenious structural design, which can effectively improve the overall service life of the cutting tap while reducing the resistance during cutting.

[0006] To achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A cutting tap that can continuously maintain the smoothness of the machining surface includes a shank and a cutting part connected to each other. The cutting part includes a number of concentric and spiral cutting edge groups; a chip groove is provided between every two cutting edge groups; each cutting edge group includes a number of first cutting units and a number of second cutting units; the number of the first cutting units and the second cutting units is the same, and they are evenly arranged in a staggered manner in the circumferential direction of the cutting part; the first cutting unit includes a first cutting edge and a first finishing edge arranged in sequence in the direction from the cutting part to the shank, the second cutting unit includes a second cutting edge and a second finishing edge arranged in sequence in the direction from the cutting part to the shank, and the heights of the first finishing edge and the second finishing edge in the radial direction of the tap are different.

[0008] As a further improvement, the number of the first cutting units and the second cutting units is two each, and the two first cutting units are distributed in central symmetry, and the two second cutting units are distributed in central symmetry.

[0009] As a further improvement, the number of the first cutting units and the second cutting units is three each, and the three first cutting units are distributed in central symmetry, and the three second cutting units are distributed in central symmetry.

[0010] As a further improvement, the height of the first correcting edge or the second correcting edge in the radial direction of the tap is equal to the radius of the hole to be machined by the tap, and the height difference between the first correcting edge and the second correcting edge in the radial direction of the tap is less than the tolerance range of the hole to be machined by the cutting tap.

[0011] As a further improvement, the height difference range between the first correcting edge and the second correcting edge in the radial direction of the tap is between 0.02 mm and 0.04 mm.

[0012] As a further improvement, the diameter of each first cutting edge increases sequentially along the direction from the cutting part to the shank part and is always smaller than the diameter of the first correcting edge; the diameter of each second cutting edge increases sequentially along the direction from the cutting part to the shank part and is always smaller than the diameter of the second correcting edge; each first cutting edge and each second cutting edge are exactly the same.

[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0014] 1. For a cutting tap capable of continuously maintaining the smoothness of the machined surface according to the present utility model, through the first cutting units and the second cutting units arranged in a uniformly staggered manner, on the one hand, it can effectively realize machining the hole with the higher correcting edge first by the different heights of the first correcting edge and the second correcting edge in the radial direction of the tap. When the higher correcting edge wears to be almost the same height as the lower correcting edge, at this time, the lower correcting edge mainly compensates, playing an accurate machining role, which can effectively and continuously ensure the smoothness of the machined surface and greatly improve the service life of the tap; on the other hand, through the structure with staggered heights, it can also be realized that before the higher correcting edge wears to be equal in height to the lower correcting edge, only the higher correcting edge contacts the machined surface. Compared with the traditional cutting tap, the contact surface is reduced by half, which can greatly reduce the resistance during the initial cutting, reduce the overall machining energy consumption and manufacturing cost.

[0015] 2. On the one hand, for a cutting tap of the present utility model that can continuously maintain the surface finish of the machined surface, by making the height of the first correction edge or the second correction edge in the radial direction of the tap equal to the radius of the hole to be machined by the tap, it is ensured that at least one of the correction edges can ensure the machining accuracy requirements. And regardless of whether the height of the other correction edge in the radial direction of the tap is larger or smaller, the machining hole can meet the tolerance range through subsequent height difference control. On the other hand, by making the height difference between the first correction edge and the second correction edge in the radial direction of the tap less than the tolerance range of the hole to be machined by the cutting tap, while ensuring that there is a height difference to achieve resistance reduction, it will not cause the lower correction edge to be unable to ensure the machining accuracy requirements during use due to too large a height difference. Brief Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can be obtained based on these drawings.

[0017] Figure 1 is a schematic structural diagram of a cutting tap of the present utility model that can continuously maintain the surface finish of the machined surface;

[0018] Figure 2 is a front view along the axial direction of the tap when the number of the first cutting units of a cutting tap of the present utility model that can continuously maintain the surface finish of the machined surface is two;

[0019] Figure 3 is a front view along the axial direction of the tap when the number of the first cutting units of a cutting tap of the present utility model that can continuously maintain the surface finish of the machined surface is three.

[0020] Main Element Symbol Description

[0021] 10. Shank; 20. Cutting part; 21. Cutting edge group; 22. Chip flutes; 211. First cutting unit; 2111. First cutting edge; 2112. First correction edge; 212. Second cutting unit; 2121. Second cutting edge; 2122. Second correction edge. Detailed Embodiment

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0024] Please refer to Figures 1 to 3 , in the embodiment, a cutting tap capable of continuously maintaining the finish of the machining surface includes a shank portion 10 and a cutting portion 20 connected to each other. The cutting portion 20 includes a plurality of concentric and helical cutting edge groups 21; a chip flute 22 is provided between every two of the cutting edge groups 21; the cutting edge group includes a plurality of first cutting units 211 and a plurality of second cutting units 212; the number of the first cutting units 211 is the same as that of the second cutting units 212, and they are arranged in a uniformly staggered manner in the circumferential direction of the cutting portion 20. The uniformly staggered arrangement can ensure that the force on any one cutting unit during operation is uniform and stable; the first cutting unit 211 includes a first cutting edge 2111 and a first correcting edge 2112 arranged in sequence along the direction from the cutting portion 20 to the shank portion 10, the second cutting unit 212 includes a second cutting edge 2121 and a second correcting edge 2122 arranged in sequence along the direction from the cutting portion 20 to the shank portion 10, and the heights of the first correcting edge 2112 and the second correcting edge 2122 in the radial direction of the tap are different.

[0025] By arranging the first cutting unit 211 and the second cutting unit 212 in a uniformly staggered manner, on the one hand, the first correction edge 2112 and the second correction edge 2122 have different heights in the radial direction of the tap, so that the hole can be effectively machined by the higher correction edge first. When the higher correction edge wears to about the same height as the lower correction edge, at this time, the lower correction edge mainly compensates, playing an accurate machining role, which can effectively and continuously ensure the smoothness of the machining surface and greatly improve the service life of the tap. On the other hand, through the structure with staggered heights, it can also be achieved that before the higher correction edge wears to the same height as the lower correction edge, only the higher correction edge contacts the machining surface. Compared with the traditional cutting tap, the contact surface is reduced by half, which can greatly reduce the resistance during the initial cutting, reduce the overall machining energy consumption and manufacturing cost.

[0026] Please refer to Figure 2 , the numbers of the first cutting unit 211 and the second cutting unit 212 are both two, and the two first cutting units 211 are symmetrically distributed about the center, and the two second cutting units 212 are symmetrically distributed about the center. When the aperture to be machined is small, the cutting action can be realized by the two first cutting units 211 or the two second cutting units 212 in the early stage to meet the machining strength requirements. At this time, the first cutting unit 211 or the second cutting unit 212 is symmetrically distributed at 180 degrees.

[0027] Please refer to Figure 3 , the numbers of the first cutting unit 211 and the second cutting unit 212 are both three, and the three first cutting units 211 are symmetrically distributed about the center, and the three second cutting units 212 are symmetrically distributed about the center. When the aperture to be machined is large, the machining strength requirements are ensured by the three first cutting units 211 or the three second cutting units 212 in the early stage. At this time, the first cutting unit 211 or the second cutting unit 212 is distributed in a triangular shape.

[0028] Please refer to Figure 2 and Figure 3 , the height of the first correction edge 2112 or the second correction edge 2122 in the radial direction of the tap is equal to the radius of the hole to be machined by the tap, and the height difference between the first correction edge 2112 and the second correction edge 2122 in the radial direction of the tap is less than the tolerance range of the hole to be machined by the cutting tap.

[0029] On the one hand, the height of the first correction edge 2112 or the second correction edge 2122 in the radial direction of the tap is equal to the radius of the hole to be machined by the tap, so as to ensure that at least one of the correction edges can ensure the machining accuracy requirements. And regardless of whether the height of the other correction edge in the radial direction of the tap is larger or smaller, the machining hole can meet the tolerance range through subsequent height difference control. On the other hand, the height difference between the first correction edge 2112 and the second correction edge 2122 in the radial direction of the tap is less than the tolerance range of the hole to be machined by the cutting tap, ensuring that there is a height difference to reduce the resistance, while not causing the lower correction edge to be unable to ensure the machining accuracy requirements during use due to too large a height difference.

[0030] For example, if the radius of the machined hole is 1 cm and the tolerance range requirement is within plus or minus 10 mm, then when the height of the first correction edge 2112 in the radial direction of the tap is equal to 1 cm, the height of the second correction edge 2122 in the radial direction of the tap is 0.9 cm to 1.1 cm. Whether the second correction edge 2122 is used first during the cutting process or later, it can meet the aperture machining requirements throughout the process.

[0031] Please refer to Figure 2 and Figure 3 , the height difference range between the first correction edge 2112 and the second correction edge 2122 in the radial direction of the tap is between 0.02 mm and 0.04 mm. Preferably, the height difference is 0.03 mm. On the one hand, if the height difference is too large, it will exceed the tolerance range and result in insufficient machining accuracy. On the other hand, if the height difference is too small, the higher correction edge will start to wear the lower correction edge not long after use, and it is impossible to ensure the service life as much as possible.

[0032] Please refer to Figures 1 to 3 , the diameter of each first cutting edge 2111 gradually increases in the direction from the cutting part 20 to the shank part 10, and is always smaller than the diameter of the first correction edge 2112; the diameter of each second cutting edge 2121 gradually increases in the direction from the cutting part 20 to the shank part 10, and is always smaller than the diameter of the second correction edge 2122; the structures and dimensions of each first cutting edge 2111 and the structures and dimensions of each second cutting edge 2121 are exactly the same, and the two are concentrically arranged. During the cutting process, drilling is carried out through the cutting edge, and then the subsequent tooth hole is cut to the same radius by the correction edge to realize the tapping process. Through this structural design, the cutting stability during the whole cutting process can be effectively ensured, and the uneven force at the beginning of tapping will not be caused, ensuring that it can smoothly transition to the process where only the higher correction edge can meet the subsequent tapping force.

[0033] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A cutting tap capable of continuously maintaining the surface finish of the machined surface, characterized in that: It includes a connected shank (10) and a cutting part (20), and the cutting part (20) includes a number of concentric and spiral cutting edge groups (21); a chip flute (22) is formed between every two of the cutting edge groups (21); the cutting edge group includes a number of first cutting units (211) and a number of second cutting units (212); the number of the first cutting units (211) is the same as that of the second cutting units (212), and they are evenly arranged in a staggered manner in the circumferential direction of the cutting part (20); the first cutting unit (211) includes a first cutting edge (2111) and a first correcting edge (2112) arranged in sequence along the direction from the cutting part (20) to the shank (10), the second cutting unit (212) includes a second cutting edge (2121) and a second correcting edge (2122) arranged in sequence along the direction from the cutting part (20) to the shank (10), and the heights of the first correcting edge (2112) and the second correcting edge (2122) in the radial direction of the tap are different.

2. The cutting tap for sustainably maintaining the surface finish of a machined surface according to claim 1, wherein: The number of both the first cutting units (211) and the second cutting units (212) is two, and the two first cutting units (211) are symmetrically distributed about the center, and the two second cutting units (212) are symmetrically distributed about the center.

3. The cutting tap for sustainably maintaining the surface finish of the machined surface according to claim 1, wherein: The number of both the first cutting units (211) and the second cutting units (212) is three, and the three first cutting units (211) are symmetrically distributed about the center, and the three second cutting units (212) are symmetrically distributed about the center.

4. The cutting tap for sustainably maintaining the surface finish of a machined surface according to any one of claims 1 to 3, characterized in that: The height of the first correcting edge (2112) or the second correcting edge (2122) in the radial direction of the tap is equal to the radius of the hole to be machined by the tap, and the height difference between the first correcting edge (2112) and the second correcting edge (2122) in the radial direction of the tap is less than the tolerance range of the hole to be machined by the cutting tap.

5. The cutting tap for sustainable maintenance of the finish of the machined surface according to claim 4, characterized in that: The height difference range between the first correcting edge (2112) and the second correcting edge (2122) in the radial direction of the tap is between 0.02 mm and 0.04 mm.

6. The cutting tap for sustainably maintaining the finish of the machined surface according to claim 4, wherein: The diameter of each first cutting edge (2111) gradually increases along the direction from the cutting part (20) to the shank (10), and is always smaller than the diameter of the first correcting edge (2112); the diameter of each second cutting edge (2121) gradually increases along the direction from the cutting part (20) to the shank (10), and is always smaller than the diameter of the second correcting edge (2122); each first cutting edge (2111) is exactly the same as each second cutting edge (2121).

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