Cutter for machining inner hole

Abstract

The utility model discloses a cutter for machining an inner hole, which comprises a cutter body, a cutting edge and a chip groove, the cutting edge and the chip groove are respectively formed on the cutter body, the cutter body comprises a cutter plane formed at the bottom, and the cutting edge comprises a first sub-cutting edge and a second sub-cutting edge; the first sub-cutting edge is arranged in the middle of the cutter plane and protrudes out of the cutter plane, and the first sub-cutting edge extends from the peripheral side of the bottom of the first sub-cutting edge to the direction away from the cutter plane and converges at the same cutting edge point at least used for positioning; the second sub-blade is formed on the edge of the cutter plane and connected with the first sub-blade, the chip groove is spiral, and the bottom of the chip groove is connected with the first sub-blade and the second sub-blade; the cutter is high in machining precision and good in machining consistency, the cutting edge of the cutting edge is good in strength and long in service life, meanwhile, machining chips are easy to discharge, and the surface of a workpiece is not prone to being damaged.

Description

Technical Field

[0001] This utility model relates to the field of machining, and in particular to the machining and forming of internal holes, specifically to a cutting tool for machining internal holes. Background Technology

[0002] In machining, different machining methods are required depending on the structure and technical requirements of the hole. For example, hole machining on a solid workpiece is to machine a hole from the solid. Since it is the machining of the inner surface of the part, it is difficult to observe and control the machining process. The machining difficulty is much greater than that of open surfaces such as outer cylindrical surfaces. At present, there are still some problems in the machining of inner holes: (1) During the machining process, the changes in shape and size caused by tool wear will directly affect the accuracy of the machined hole. Therefore, the tool needs to have good strength; (2) In the initial stage of machining, the tool is prone to vibration when subjected to instantaneous force, resulting in poor machining consistency; (3) When machining holes, the tool generally works in a semi-enclosed space, making it difficult to remove chips. If too many chips accumulate on the workpiece, it will easily cause the workpiece surface to be scratched. Utility Model Content

[0003] The purpose of this invention is to overcome one or more deficiencies in the prior art and provide an improved tool for machining internal holes.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A tool for machining internal holes includes a tool body, and a cutting edge and a chip removal groove formed on the tool body. The tool body includes a tool plane formed at the bottom. The cutting edge includes a first sub-cutting edge and a second sub-cutting edge. The first sub-cutting edge is disposed at the center of the tool plane and protrudes from the tool plane. The first sub-cutting edge extends from its circumferential side at its bottom in a direction away from the tool plane and converges at least at the same cutting tip for positioning. The second sub-cutting edge is formed at the edge of the tool plane and connected to the first sub-cutting edge. The chip removal groove is helical and its bottom is connected to the first sub-cutting edge and the second sub-cutting edge, respectively.

[0006] According to some preferred aspects of this utility model, the distance between the cutting edge and the cutting tool plane is 0.1-1mm. In some embodiments of this utility model, the distance between the cutting edge and the cutting tool plane is 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0007] According to some preferred aspects of the present invention, the blade tip is located on the axis of the blade body.

[0008] According to some preferred aspects of the present invention, the cutting edge of the second sub-blade is formed on the boundary line between the bottom of the chip removal groove and the plane of the tool.

[0009] According to some preferred aspects of the present invention, the cutting edge of the second sub-blade includes a forward rotating cutting edge and a reverse rotating cutting edge, each of the forward rotating cutting edge and the reverse rotating cutting edge independently including two sub-blades, and one of the two sub-blades can coincide with the other after rotating 180° relative to the center of the tool plane.

[0010] Furthermore, one of the forward rotating cutting edges is symmetrically arranged with one of the reverse rotating cutting edges, and the other cutting edge in the forward rotating cutting edge is symmetrically arranged with the other cutting edge in the reverse rotating cutting edge. The two symmetrically arranged cutting edges are located on the same side of the first sub-blade.

[0011] According to some preferred aspects of this utility model, the length of the cutting edge of the second sub-blade is L, 2R1>L+R2>R1, and R2 is less than or equal to one-third of R1, R1 is the radius of the circle containing the plane of the tool, and R2 is the radius of the circle containing the bottom of the first sub-blade.

[0012] According to some preferred aspects of the present invention, the connection portion between the first sub-blade and the chip removal groove is recessed towards the first sub-blade.

[0013] According to some preferred aspects of the present invention, the connecting portion is also connected to the cutting edge of the second sub-blade.

[0014] According to some preferred aspects of this utility model, the helical angle of the spiral chip removal groove is 20°-40°. In some embodiments of this utility model, the helical angle of the spiral chip removal groove is 20°, 22°, 24°, 26°, 28°, 30°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, etc.

[0015] In some embodiments of this utility model, the chip removal groove has multiple grooves.

[0016] According to some preferred aspects of the present invention, the cutting edge further includes a third sub-cutting edge, which is a chamfered cutting edge and located above the plane of the cutting tool, and the chip removal groove passes through the third sub-cutting edge.

[0017] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:

[0018] This invention innovatively designs the tool structure by integrating a first sub-cutting edge, which serves a positioning function, and a second sub-cutting edge, used for machining internal holes, onto the same tool plane. The first sub-cutting edge protrudes from the tool plane. During machining, the first sub-cutting edge contacts the workpiece first, utilizing its cutting tip for positioning during drilling. This ensures a stable machining state for the second sub-cutting edge upon initial contact with the workpiece, reducing vibration caused by the instantaneous force applied to the tool. This better guarantees the hole diameter, improves the consistency and stability of internal hole machining, and prevents chipping of the second sub-cutting edge due to vibration, thus extending the service life of the second tool. In particular, this invention forms the second sub-cutting edge on the edge of the tool plane and connects it to the first sub-cutting edge... The first and second sub-cutting edges are connected to the bottom of the chip removal groove, ensuring that the second sub-cutting edge is not suspended or protruding. When subjected to external forces such as reaction forces generated during machining, it has the ability to quickly discharge and disperse the force. This means that it does not bear the external force independently, but rather shares the force as a whole with other structures and / or components, greatly improving rigidity and strength and reducing the possibility of edge breakage. In addition, since the bottom of the chip removal groove is connected to both the first and second sub-cutting edges simultaneously, based on their positional relationship with the tool plane, the generated machining chips can be quickly discharged through the chip removal groove, reducing the accumulation of machining chips caused by interference from the arrangement of the cutting edges. This also avoids the problem of excessive chip accumulation on the workpiece surface causing scratches when working in a semi-enclosed space. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is one of the structural schematic diagrams of the tool for machining internal holes according to this utility model;

[0021] Figure 2 This is a bottom view of the cutting tool for machining internal holes according to this utility model;

[0022] Figure 3 This is the second schematic diagram of the tool for machining internal holes according to this utility model;

[0023] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0024] Figure 5 This is the third schematic diagram of the structure of the tool for machining internal holes according to this utility model;

[0025] Figure 6 This is the fourth schematic diagram of the tool for machining internal holes according to this utility model;

[0026] Figure 7 for Figure 6 Enlarged view of point B in the middle;

[0027] In the attached figures: 100, cutter body; 111, first sub-cutting edge; 1111, cutting edge tip; 112, second sub-cutting edge; 1121, forward rotating cutting edge; 1122, reverse rotating cutting edge; 113, third sub-cutting edge; 120, chip removal groove; 130, tool plane; 140, connecting part; 150, tool holder; α, helix angle; h, distance between cutting edge tip and tool plane; s, axis. Detailed Implementation

[0028] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a full understanding of the present utility model. However, the present utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present utility model. Therefore, the present utility model is not limited to the specific embodiments disclosed below.

[0029] In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0032] like Figures 1 to 7 As shown, this example provides a tool for machining internal holes, which includes a tool body 100 and a cutting edge and a chip removal groove 120 respectively formed on the tool body 100.

[0033] In this example, the blade body 100 includes a blade plane 130 formed at the bottom, and the blade includes a first sub-blade 111 and a second sub-blade 112. The first sub-blade 111 is disposed in the middle of the blade plane 130 and protrudes from the blade plane 130. The first sub-blade 111 extends from its own bottom periphery in a direction away from the blade plane 130 and converges at least at the same blade tip 1111 used for positioning. The second sub-blade 112 is formed on the edge of the blade plane 130 and is connected to the first sub-blade 111. The chip removal groove 120 is spiral and its bottom is connected to the first sub-blade 111 and the second sub-blade 112 respectively.

[0034] The distance h between the cutting tip 1111 and the tool plane 130 is 0.1-1 mm. Optionally, the distance h between the cutting tip and the tool plane is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc. In this example, by controlling the distance between the cutting tip 111 and the tool plane 130, the accumulation of machining chips between the tool plane and the workpiece can be further reduced or even avoided. At the same time, it can also ensure that only a small indentation is formed at the bottom of the machined inner hole, thereby achieving efficient positioning while reducing undesirable adverse effects on the consistency of the inner hole.

[0035] The cutting tip 1111 is located on the axis s of the tool body 100. This setting ensures that the center of the machining process remains on the axis, and also makes the tool as a whole basically symmetrical, thus contributing to overall machining balance and improving machining accuracy and consistency. Figure 1 As shown, during machining, the cutting tip 1111 first contacts the workpiece to be machined. The cutting tip 1111 is very sharp, which can quickly penetrate into the workpiece to play a positioning role. The generated machining chips can also be directly discharged from the adjacent chip removal groove.

[0036] The cutting edge of the second sub-cutting edge 112 is formed on the dividing line between the bottom of the chip removal groove 120 and the tool plane 130. This arrangement allows the second sub-cutting edge 112 to exist relying on the tool plane 130 and the chip removal groove 120. As a result, the force during machining is not entirely borne by the second sub-cutting edge 112, but can be transmitted to the wall of the directly connected first sub-cutting edge 111 and the chip removal groove 120, reducing the possibility of edge breakage and improving strength and rigidity. It also facilitates rapid cutting. At the same time, the machining chips generated can be directly discharged upward and outward along the chip removal groove 120, reducing the situation where machining chips remain in the hole.

[0037] The cutting edge of the second sub-cutting edge 112 includes a forward rotating cutting edge 1121 and a reverse rotating cutting edge 1122. Each of the forward rotating cutting edge 1121 and the reverse rotating cutting edge 1122 independently includes two sub-cutting edges. One of these two sub-cutting edges can coincide with the other after rotating 180° relative to the center of the tool plane 130. Furthermore, one cutting edge of the forward rotating cutting edge 1121 is symmetrically arranged with one cutting edge of the reverse rotating cutting edge 1122, and the other cutting edge of the forward rotating cutting edge 1121 is symmetrically arranged with the other cutting edge of the reverse rotating cutting edge 1122. The two symmetrically arranged cutting edges are located on the same side of the first sub-cutting edge 111.

[0038] In reality, the terms "forward rotating cutting edge 1121" and "reverse rotating cutting edge 1122" are only relative terms. For example, a cutting edge that functions when rotating clockwise can be called a forward rotating cutting edge, and a cutting edge that functions when rotating counterclockwise can be called a reverse rotating cutting edge. In this example, see... Figure 4 As shown in the figure, taking the perspective shown as an example, when rotating clockwise, the forward rotating cutting edge 1121 on the upper right side will perform a cutting action, and the generated chips will be discharged upward and outward from the chip removal groove 120 directly connected to it. At the same time, the forward rotating cutting edge 1121 on the lower left side (located on both sides of the first sub-cutting edge 111 with the forward rotating cutting edge 1121 on the upper right side) will perform the same cutting action, and the generated chips will also be discharged upward and outward from the chip removal groove 120 directly connected to it. When rotating counterclockwise, the reverse rotating cutting edge 1122 on the upper left side will perform a cutting action, and the generated chips will be discharged upward and outward from the chip removal groove 120 directly connected to it. At the same time, the reverse rotating cutting edge 1122 on the lower right side (located on both sides of the first sub-cutting edge 111 with the reverse rotating cutting edge 1122 on the upper left side) will perform the same cutting action, and the generated chips will also be discharged upward and outward from the chip removal groove 120 directly connected to it. Therefore, there are multiple chip removal grooves 120 in this example, for example, at least two can be provided. Meanwhile, in this example, during the machining process, only two cutting edges of the second sub-cutting edge 112 will simultaneously perform cutting action, while the first sub-cutting edge 111 always plays a corresponding positioning role, and the chip removal groove 120 always plays a chip removal role when machining chips are generated.

[0039] The length of the cutting edge of the second sub-blade 112 is L, 2R1 > L + R2 > R1, and R2 is less than or equal to one-third of R1. R1 is the radius of the circle containing the tool plane 130, and R2 is the radius of the circle containing the bottom of the first sub-blade 111. In this example, see... Figure 2 and Figure 4As shown, the tool plane 130 is generally circular. Of course, due to the presence of the chip removal groove 120, part of it is removed, but the overall outline is roughly circular. Similarly, the bottom of the first sub-cutting edge 111 is also roughly circular and part of it is also removed. In this example, the length of the cutting edge of the second sub-cutting edge 112 is L, and the sum of the radius of the circle where the bottom of the first sub-cutting edge 111 is located is greater than the radius of the circle where the tool plane 130 is located and less than the diameter of the circle where the tool plane 130 is located. By controlling the length of the cutting edge of the second sub-cutting edge 112 in this way, it can ensure the maximum cutting efficiency while controlling the size of the machining chips within a certain range. This avoids the situation where existing tools are set too long in order to pursue the cutting amount per cycle, resulting in larger machining chip sizes. When the machining chip size is large, it is easy to scratch the surface of the workpiece being machined.

[0040] The connecting portion 140 of the first sub-cutting edge 111 and the chip removal groove 120 is recessed towards the first sub-cutting edge 111. This arrangement facilitates the movement of machining chips generated by the second sub-cutting edge 112 towards the chip removal groove 120 and also allows control over the length of the cutting edge of the second sub-cutting edge 112. Simultaneously, the connecting portion 140 is also connected to the cutting edge of the second sub-cutting edge 112, thus making the first sub-cutting edge 111, the second sub-cutting edge 112, and the chip removal groove 120 an organic whole, improving their synergistic effect, increasing the strength of the cutting edge, and facilitating the removal of machining chips.

[0041] The cutting edge also includes a third sub-cutting edge 113, which is a chamfered cutting edge located above the tool plane 130. The chip removal groove 120 passes through the third sub-cutting edge 113. In this example, the third sub-cutting edge 113 is integrated onto the same tool, achieving simultaneous machining of the chamfer at the exit of the inner hole while machining the inner hole. This reduces the complexity of using multiple tools and shortens the machining time, thereby improving work efficiency and achieving cost reduction and efficiency improvement. The distance between the third sub-cutting edge 113 and the machining plane 130 can be adjusted according to the depth of the inner hole to be machined; this example does not impose a specific limitation.

[0042] The helix angle α of the helical chip removal groove 120 is 20°-40°. Optionally, the helix angle α of the helical chip removal groove 120 can be 20°, 22°, 24°, 26°, 28°, 30°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, etc. Currently, the helix angle of the chip removal groove in traditional cutting tools is usually 55° to 60°. However, in practice, this angle is not suitable for the case where a chamfering edge is formed, as the chamfering edge needs to have a certain angle, such as 45°. If the helix angle of the chip removal groove is designed according to 55° to 60°, the machining chips generated will easily scratch the chamfered surface. In particular, the cutting edge length of the second sub-cutting edge 112 in this example is relatively short, and the size of the machining chips generated is small. With the helix angle in this example, chips can be removed in a nearly perpendicular manner, without scratching the chamfered surface, and it can also achieve the effect of rapid chip removal.

[0043] In this example, the cutting tool can be made of metal, such as stainless steel, diamond, etc.

[0044] In summary, this utility model innovatively designs the tool structure by integrating a first sub-cutting edge with a positioning function and a second sub-cutting edge for machining internal holes onto the same tool plane, with the first sub-cutting edge protruding from the tool plane. During machining, the first sub-cutting edge first contacts the workpiece, using its cutting tip to position the hole, thus ensuring a stable machining state when the second sub-cutting edge starts working. This reduces the vibration caused by the instantaneous force when the tool first contacts the workpiece, better ensuring the hole diameter, improving the consistency and stability of internal hole machining, and preventing chipping of the cutting edge of the second sub-cutting edge due to vibration, thereby increasing the service life of the second tool. In particular, this utility model forms the second sub-cutting edge on the edge of the tool plane and respectively... The second sub-cutting edge is connected to the bottom of the first sub-cutting edge and the chip removal groove, so that the second sub-cutting edge is not suspended or protruding. When subjected to external forces such as reaction forces generated during machining, it has the ability to quickly discharge and disperse the force. It is equivalent to not bearing the external force independently, but sharing the force as a whole with other structures and / or components, which greatly improves rigidity and strength and reduces the possibility of edge breakage. In addition, since the bottom of the chip removal groove is connected to both the first and second sub-cutting edges at the same time, based on their positional relationship with the tool plane, the generated machining chips can be quickly discharged through the chip removal groove, reducing the accumulation of machining chips caused by interference from the arrangement of the cutting edges, and avoiding the problem of excessive accumulation of workpiece residue and scratching the workpiece surface when working in a semi-enclosed space.

[0045] The above embodiments are only for illustrating the technical concept and features of this utility model. Their purpose is to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be used to limit the protection scope of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the protection scope of this utility model.

Claims

1. A tool for machining an internal hole, comprising a tool body, and a cutting edge and a chip flute formed on the tool body, respectively, characterized in that, The cutter body comprises a cutter plane formed on the bottom, the cutting edge comprises a first sub-cutting edge and a second sub-cutting edge; the first sub-cutting edge is arranged at the middle of the cutter plane and protrudes from the cutter plane, and the first sub-cutting edge extends from the circumferential side of the bottom thereof to a direction away from the cutter plane and converges at the same blade tip for positioning; the second sub-cutting edge is formed at the edge of the cutter plane and connected with the first sub-cutting edge, and the chip flute is helical and the bottom thereof is connected with the first sub-cutting edge and the second sub-cutting edge, respectively.

2. A tool for machining an internal bore according to claim 1, characterised in that The distance between the blade tip and the cutter plane is 0.1-1mm; and / or, the blade tip is located on the axial center line of the cutter body.

3. The tool for machining an internal bore defined in claim 1, wherein, The blade edge of the second sub-cutting edge is formed on the boundary line between the bottom of the chip flute and the cutter plane.

4. The tool for machining an internal bore defined in claim 1, wherein, The blade edge of the second sub-cutting edge comprises a forward rotation blade edge and a reverse rotation blade edge, the forward rotation blade edge and the reverse rotation blade edge each independently comprise two sub-blade edges, and one of the two sub-blade edges can coincide with the other after rotating 180° relative to the center of the cutter plane.

5. A tool for machining an internal bore according to claim 4, characterised in that, One of the forward rotation blade edges is symmetrically arranged with one of the reverse rotation blade edges, the other of the forward rotation blade edges is symmetrically arranged with the other of the reverse rotation blade edges, and the two symmetrically arranged blade edges are located on the same side of the first sub-cutting edge.

6. The tool for machining an internal bore defined by claim 1, characterized in that, The length of the blade edge of the second sub-cutting edge is L, L+R2>R1, and R2 is less than or equal to one-third of R1, R1 is the radius of the circle on which the cutter plane is located, and R2 is the radius of the circle on which the bottom of the first sub-cutting edge is located.

7. The tool for machining an internal bore defined by claim 1, characterized in that, The connecting part of the first sub-cutting edge and the chip flute is concave to the first sub-cutting edge.

8. A tool for machining an internal bore according to claim 7, characterised in that The connecting part is also connected with the blade edge of the second sub-cutting edge.

9. The tool for machining an internal bore defined by claim 1, characterized in that, The helical angle of the helical chip flute is 20°-40°; and / or, the chip flute has multiple.

10. The tool for machining an internal bore defined by claim 1, characterized in that, The cutting edge further comprises a third sub-cutting edge, the third sub-cutting edge is a chamfering cutting edge and is located above the cutter plane, and the chip flute passes through the third sub-cutting edge.

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