Negative chamfering tool

Abstract

The present invention provides a negative chamfer tool, comprising: a tool body; a tool head, the tool head is connected to the tool body, two negative chamfers of different heights are formed at the tip of the tool head, the negative chamfers extend along the circumference of the tool head, an inclined chamfer surface is formed between the two negative chamfers, the chamfer surface has a first curved surface segment, a second curved surface segment and a third curved surface segment extending in the circumference and connected in sequence, and the second curved surface segment is located at the symmetry axis of the tool head, the negative chamfer angle of the second curved surface segment is unchanged, and the negative chamfer angles or widths of the first curved surface segment and the third curved surface segment are continuously increased or decreased. The present invention solves the problem that it is relatively complicated to design a wiper blade for a PCBN tool in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of cutting tools, and in particular to a negative chamfering cutting tool. Background Art

[0002] Negative chamfer means that after the tool is sharpened, a very narrow plane is ground at a certain angle on the edge to prevent the blade from chipping. Its function is to enhance the edge strength.

[0003] As a common tool material in superhard cutting, cubic boron nitride has the characteristics of high hardness, good wear resistance, and good chemical stability, making it very suitable for finishing of iron-based materials. Taking advantage of its physical properties, artificially synthesized PCBN (i.e. polycrystalline cubic boron nitride) as a superhard tool material has a natural advantage in processing iron-based metal materials. Most of the current PCBN tools require a separate design of the wiper edge to achieve the wiper edge effect. There are many factors to consider in the separate design, and the design process is relatively cumbersome and complicated. Summary of the invention

[0004] The main purpose of the present invention is to provide a negative chamfering tool to solve the problem that the PCBN tool in the prior art is relatively complicated in designing a wiper edge separately.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a negative chamfer tool, comprising: a tool body; a tool head, the tool head is connected to the tool body, two negative chamfers of different heights are formed at the tip of the tool head, the negative chamfers extend along the circumference of the tool head, an inclined chamfer surface is formed between the two negative chamfers, the chamfer surface has a first curved surface segment, a second curved surface segment and a third curved surface segment extending circumferentially and connected in sequence, and the second curved surface segment is located at the symmetry axis of the tool head, the negative chamfer angle of the second curved surface segment remains unchanged, and the negative chamfer angles or widths of the first curved surface segment and the third curved surface segment continuously increase or decrease.

[0006] Furthermore, the first curved surface segment and the third curved surface segment are symmetrically arranged on both sides of the second curved surface segment.

[0007] Furthermore, the negative chamfer angles or widths at symmetrical positions of the first curved surface segment and the third curved surface segment are equal.

[0008] Furthermore, the negative chamfer angles of the first curved surface segment, the second curved surface segment and the third curved surface segment are 10° to 30°.

[0009] Furthermore, an end of the first curved surface segment away from the second curved surface segment has a finishing point.

[0010] Furthermore, an end of the first curved surface segment or the third curved surface segment close to the second curved surface segment forms a first angle line with the center of the second curved surface segment, and an angle α formed between the first angle line and the symmetry axis of the tool head is in the range of 0°-30°.

[0011] Furthermore, an end of the first curved surface segment or the third curved surface segment away from the second curved surface segment forms a second angle line with the center of the second curved surface segment, and an angle β formed between the second angle line and the symmetry axis of the tool head is in the range of 80°-120°.

[0012] Furthermore, the width between the two negative chamfers is 0.1 to 0.3 mm.

[0013] Furthermore, the chamfered surface also includes a first straight surface segment and a second straight surface segment, the first straight surface segment is connected to an end of the first curved surface segment away from the second curved surface segment, and the second straight surface segment is connected to an end of the third curved surface segment away from the second curved surface segment.

[0014] Furthermore, the negative chamfer angles of the first straight surface segment and the second straight surface segment are equal everywhere or unequal at least in one place.

[0015] Furthermore, the cutter body has a polygonal structure, a recess is provided at the top corner of the polygonal structure, and the cutter head is embedded in the recess.

[0016] Furthermore, the cutter head is a polycrystalline cubic boron nitride cutter head.

[0017] By applying the technical solution of the present invention, the tip of the negative chamfering tool is negatively chamfered, so that the reliability of the negative chamfering tool during use can be improved, and the chamfering surface is provided with a structure of a first curved surface segment, a second curved surface segment and a third curved surface segment, wherein the negative chamfering angle of the second curved surface segment remains unchanged, and the negative chamfering angle or width of the first curved surface segment and the third curved surface segment continuously increases or decreases to form a gradual form, so that the cutting edge point drop formed by the gradual change of the negative chamfering angle or width achieves the effect of angle finishing, that is, the tip of the negative chamfering surface forms a certain width difference in the width direction, thereby achieving the finishing edge effect, improving the practicality and processing efficiency of the tool. In addition, the negative chamfering angle or width increases or decreases smoothly and continuously, which also improves the impact of the cutting force and cutting temperature on the negative chamfering tool during the cutting process, changes the chip flow direction to reduce the wear of the crater, and improves the service life of the negative chamfering tool. The above setting method takes into account that the contact point positions during processing are different for negative chamfers of different angles and widths. In order to improve the applicability of the tool, the difference in the contact point of the cutting edge is used to form the effect of a wiper edge. While ensuring the strength of the cutting edge, the processing efficiency can be appropriately improved, and there is no need for a separate design, which simplifies the design process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1A schematic structural diagram of a negative chamfering tool according to the present invention is shown;

[0020] Figure 2 Shows Figure 1 The enlarged view of the points marked at P in the figure;

[0021] Figure 3 Shows Figure 1 The enlarged view of the angle α and angle β marked at P in the middle;

[0022] Figure 4 Shows Figure 1 Sectional view along AA direction;

[0023] Figure 5 Shows Figure 1 Cross-sectional view along the BB direction;

[0024] Figure 6 Shows Figure 1 Schematic diagram of the negative chamfer angle, negative chamfer width and width difference of the negative chamfer tool.

[0025] The above drawings include the following reference numerals:

[0026] 10. Cutter body; 20. Cutter head; 21. First curved surface segment; 22. Second curved surface segment; 23. Third curved surface segment; 24. First straight surface segment; 25. Second straight surface segment. DETAILED DESCRIPTION

[0027] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0029] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0030] In order to solve the problem that it is relatively complicated to design a wiper edge separately for a PCBN tool in the prior art, the present invention provides a negative chamfering tool.

[0031] like Figures 1 to 5A negative chamfer tool shown in the figure includes a tool body 10 and a tool head 20. The tool head 20 is connected to the tool body 10. Two negative chamfers of different heights are formed at the tip of the tool head 20. The negative chamfers extend along the circumference of the tool head 20. An inclined chamfer surface is formed between the two negative chamfers. The chamfer surface has a first curved surface segment 21, a second curved surface segment 22 and a third curved surface segment 23 that extend circumferentially and are connected in sequence. The second curved surface segment 22 is located at the symmetry axis of the tool head 20. The negative chamfer angle of the second curved surface segment 22 remains unchanged, and the negative chamfer angles or widths of the first curved surface segment 21 and the third curved surface segment 23 continuously increase or decrease.

[0032] In this embodiment, the tip of the negative chamfering tool is negatively chamfered to improve the reliability of the negative chamfering tool during use, and the chamfering surface is provided with a structure of a first curved surface segment 21, a second curved surface segment 22 and a third curved surface segment 23, wherein the negative chamfering angle of the second curved surface segment 22 remains unchanged, and the negative chamfering angle or width of the first curved surface segment 21 and the third curved surface segment 23 is continuously increased or decreased to form a gradual form, so that the cutting edge point drop formed by the gradual change of the negative chamfering angle or width achieves the effect of angle trimming, that is, the tip of the negative chamfering surface forms a certain width difference in the width direction, thereby achieving the trimming effect, improving the practicality and processing efficiency of the tool. In addition, the negative chamfering angle or width increases or decreases smoothly and continuously, which also improves the impact of the cutting force and cutting temperature on the negative chamfering tool during the cutting process, changes the chip flow direction to reduce the crater wear, and improves the service life of the negative chamfering tool. The above setting method takes into account that the contact point positions during processing are different for negative chamfers of different angles and widths. In order to improve the applicability of the tool, the difference in the contact point of the cutting edge is used to form the effect of a wiper edge. While ensuring the strength of the cutting edge, the processing efficiency can be appropriately improved, and there is no need for a separate design, which simplifies the design process.

[0033] The negative chamfering tool in this embodiment is mainly for the PCBN negative chamfering tool whose tool head 20 is a polycrystalline cubic boron nitride tool head, and the tool as a whole is a positive angle tool, that is, a tool with a back angle greater than 0°. The upper and lower heights, horizontal and vertical, etc. in this embodiment are described based on the state of the tool when it is usually used. After the negative chamfering treatment is performed on the tool tip, the tool tip naturally forms two upper and lower negative chamfers, of which there are six arc segments, specifically including Figure 4The area surrounded by the six arc-shaped negative chamfers AB, AE, BF, ab, ae, bf and the straight lines Ee and Ff is the curved surface portion of the chamfered surface formed by the negative chamfering treatment. This portion extends a certain distance along the circumference of the cutter head 20. In this portion, AE, ae, Aa, Ee are surrounded by the first curved surface segment 21, AB, ab, Aa, Bb are surrounded by the second curved surface segment 22, BF, bf, Bb, Ff are surrounded by the third curved surface segment 23, and the straight line Oo is the symmetry axis of the cutter head 20, which is also the symmetry axis of the second curved surface segment 22. Since the cutter head 20 of this embodiment adopts a rhombus shape, the chamfered surface is formed according to the top view. Figure 1 The rhombuses shown extend circumferentially.

[0034] A two-dimensional section is formed by cutting along a direction perpendicular to a certain point of the chamfer surface. In this section, the angle between the straight line formed by the chamfer surface and the horizontal plane is a negative chamfer angle, that is, Figure 6 The horizontal distance between the left and right end points of the chamfer surface in the section view is the negative chamfer width, that is, Figure 6 The difference w between the widths of the two negative chamfers L1 and L2 is the width difference, and the width difference w is also an important parameter affecting the angle trimming effect. Figure 4 The section AA shown is a section through point Aa, with a negative chamfer angle η and a negative chamfer width W2; Figure 5 The cross section BB shown is a sectional plane passing through point Dd, with a negative chamfer angle γ and a negative chamfer width W1.

[0035] It should be noted that the first curved surface segment 21 and the third curved surface segment 23 can adopt any one of a negative chamfer angle gradient and a width gradient. More specifically, referring to Figure 6 As shown in the angles and widths, according to the needs of different offset finishing, the negative chamfer angles ∠a and ∠b can be equal, and the negative chamfer widths L1 and L2 can gradually change from L1 to L2; or the negative chamfer angles ∠a and ∠b can gradually change from ∠a to ∠b, and the negative chamfer widths L1 and L2 can be equal.

[0036] In this embodiment, the first curved surface segment 21 and the third curved surface segment 23 are symmetrically arranged on both sides of the second curved surface segment 22. The symmetry axis of the entire curved surface portion formed by the first curved surface segment 21, the second curved surface segment 22 and the third curved surface segment 23 is also the symmetry axis of the cutter head 20. In this way, the three curved surface segments are symmetrically arranged as a whole. Of course, the first curved surface segment 21 and the third curved surface segment 23 can also be arranged in an asymmetrical form.

[0037] Preferably, the negative chamfer angles at the symmetrical positions of the first curved surface segment 21 and the third curved surface segment 23 are equal. When the negative chamfer width is gradually changed, the negative chamfer widths at the symmetrical positions of the first curved surface segment 21 and the third curved surface segment 23 can be set to be equal.

[0038] It should be noted that the negative chamfer angles of the first curved surface segment 21 and the third curved surface segment 23 can be continuously increased or continuously decreased from the end close to the second curved surface segment 22 to the end away from the second curved surface segment 22. The specific change method can be set accordingly according to the actual application scenario, as long as it is ensured to be a smooth and continuous change.

[0039] In this embodiment, the negative chamfer angles of the first curved surface segment 21, the second curved surface segment 22 and the third curved surface segment 23 are 10° to 30°. More specifically, in this embodiment, the negative chamfer angle of the second curved surface segment 22 is 20°-30°, and the negative chamfer angles of the first curved surface segment 21 and the third curved surface segment 23 are 10°-30°. When the negative chamfer width is gradually changed, the width between the two negative chamfers is 0.1 to 0.3mm. More specifically, the negative chamfer width of the second curved surface segment 22 is 0.1-0.3mm. Naturally, the negative chamfer widths of the first curved surface segment 21 and the third curved surface segment 23 are 0.1-0.3mm at the maximum, and 0.1-0.2mm at the minimum.

[0040] In this embodiment, one end of the first curved surface segment 21 away from the second curved surface segment 22 has a finishing point, that is, Figure 2 Point E in the figure is the finishing point, which is the high point formed by the cutter head 20 placed on the cutter body 10 and is also the deepest point when the cutter contacts the workpiece when in use. The straight line ED or the straight line FC has a real finishing effect, that is, the edge drop of the straight line ED is smaller than that of a normal cutter with a constant angle and width, so that the finishing effect can be achieved.

[0041] Preferably, the outer side of the first curved surface segment 21 of this embodiment has a negative chamfer, that is, Figure 2 AB in the figure is an arc, and the center of the arc is located on the symmetry axis of the cutter head 20. Similarly, AE and BF are also gradually changing arcs. The end of the first curved surface segment 21 or the third curved surface segment 23 close to the second curved surface segment 22 forms a first angle line with the center of the second curved surface segment 22, and the end of the first curved surface segment 21 or the third curved surface segment 23 away from the second curved surface segment 22 forms a second angle line with the center of the second curved surface segment 22. Figure 3 As shown, the angle α formed between the first angle line and the axis of symmetry of the cutter head 20 is in the range of 0°-30°, and the angle β formed between the second angle line and the axis of symmetry of the cutter head 20 is in the range of 80°-120°, so that the cutting edge point difference can achieve the effect of angle finishing.

[0042] In this embodiment, the chamfered surface further includes a first straight surface segment 24 and a second straight surface segment 25. The first straight surface segment 24 is connected to an end of the first curved surface segment 21 away from the second curved surface segment 22, and the second straight surface segment 25 is connected to an end of the third curved surface segment 23 away from the second curved surface segment 22. Figure 2 As shown, the area between the straight lines DE and de is the first straight surface segment 24, and the area between the straight lines FC and fc is the second straight surface segment 25. The first straight surface segment 24 and the second straight surface segment 25 extend away from one end of the corresponding curved surface segment to dock with the blade body 10, thereby forming a straight surface portion of the chamfered surface.

[0043] Similar to the symmetrical arrangement of the three curved surface segments, the first straight surface segment 24 and the second straight surface segment 25 are also symmetrically arranged on both sides of the curved surface segment, so that the chamfered surface is formed as a whole in a symmetrical form with the symmetry axis of the cutter head 20 as the axis. Of course, the above segments can also be arranged in an asymmetrical manner.

[0044] Optionally, the negative chamfer angles of the first straight surface segment 24 and the second straight surface segment 25 are equal everywhere. Since the negative chamfer angles of the first curved surface segment 21 and the third curved surface segment 23 are 10° to 30°, the negative chamfer angles of the first straight surface segment 24 and the second straight surface segment 25 are also 10° to 30°. Of course, the negative chamfer angles of the first straight surface segment 24 and the second straight surface segment 25 can also be set to be unequal at least in one place as required.

[0045] Optionally, the blade body 10 may have a polygonal structure such as a square, triangle, hexagon, or rhombus of various angles. In this embodiment, an 80° rhombus is selected, and a recess is provided at the top corner of the rhombus, and the blade head 20 is embedded in the recess.

[0046] It should be noted that, the multiple in the above embodiments refers to at least two.

[0047] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0048] 1. It solves the problem of complicated design of the wiper blade for PCBN tools in the prior art;

[0049] 2. The cutting edge point difference formed by negative chamfer angle or width gradient can achieve the effect of angle finishing, thereby improving the finishing effect, the practicality of the tool and the processing efficiency;

[0050] 3. Improve the impact of cutting force and cutting temperature on negative chamfering tools during cutting, change the chip flow direction to reduce crater wear, and increase the service life of negative chamfering tools;

[0051] 4. The overall structure is simple, easy to use and process, and the effect is stable and reliable.

[0052] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0053] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A negative chamfering tool, characterized in that: include: A knife body (10); A cutter head (20), the cutter head (20) being connected to the cutter body (10), the tip of the cutter head (20) being formed with two negative chamfers of different heights, the negative chamfers extending in the circumferential direction of the cutter head (20), an inclined chamfer surface being formed between the two negative chamfers, the chamfer surface having a first curved surface segment (21), a second curved surface segment (22) and a third curved surface segment (23) extending in the circumferential direction and connected in sequence, the second curved surface segment (22) being located at the symmetry axis of the cutter head (20), the negative chamfer angle of the second curved surface segment (22) being unchanged, and the negative chamfer angles or widths of the first curved surface segment (21) and the third curved surface segment (23) being continuously increased or decreased; An end of the first curved surface segment (21) away from the second curved surface segment (22) has a finishing point; An end of the first curved surface segment (21) or the third curved surface segment (23) close to the second curved surface segment (22) forms a first angle line with the center of the second curved surface segment (22), and an angle α formed between the first angle line and the symmetry axis of the cutter head (20) is in the range of 0°-30°; An end of the first curved surface segment (21) or the third curved surface segment (23) away from the second curved surface segment (22) forms a second angle line with the center of the second curved surface segment (22), and an angle β formed between the second angle line and the axis of symmetry of the tool head (20) is in the range of 80°-120°.

2. The negative chamfering tool according to claim 1, characterized in that: The first curved surface segment (21) and the third curved surface segment (23) are symmetrically arranged on both sides of the second curved surface segment (22).

3. The negative chamfering tool according to claim 2, characterized in that: The negative chamfer angles or widths at symmetrical positions of the first curved surface segment (21) and the third curved surface segment (23) are equal.

4. The negative chamfering tool according to claim 1, characterized in that: The negative chamfer angles of the first curved surface segment (21), the second curved surface segment (22) and the third curved surface segment (23) are 10° to 30°.

5. The negative chamfering tool according to claim 1, characterized in that: The width between the two negative chamfers is 0.1 to 0.3 mm.

6. The negative chamfering tool according to claim 1, characterized in that: The chamfered surface further comprises a first straight surface segment (24) and a second straight surface segment (25), wherein the first straight surface segment (24) is connected to an end of the first curved surface segment (21) away from the second curved surface segment (22), and the second straight surface segment (25) is connected to an end of the third curved surface segment (23) away from the second curved surface segment (22).

7. The negative chamfering tool according to claim 6, characterized in that: The negative chamfer angles of the first straight surface segment (24) and the second straight surface segment (25) are equal everywhere or unequal at least in one place.

8. The negative chamfering tool according to claim 1, characterized in that: The blade body (10) has a polygonal structure, a recess is provided at the top corner of the polygonal structure, and the blade head (20) is embedded in the recess.

9. The negative chamfering tool according to claim 1, characterized in that: The cutter head (20) is a polycrystalline cubic boron nitride cutter head.

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