Milling inserts and disc milling cutters

Abstract

This invention belongs to the field of gear machining technology and discloses a milling insert and a disc milling cutter. The milling insert is mounted on the end faces of both sides of the milling cutter disc. The insert includes a top cutting edge, a side cutting edge, and a secondary cutting edge, with the top cutting edge positioned between the side cutting edge and the secondary cutting edge. The outer contour of the top cutting edge convexes towards the workpiece and includes a top cutting edge arc and a Bézier curve. One end of the top cutting edge arc connects to the outer contour of the side cutting edge, and the other end is endpoint E. One end of the Bézier curve connects to endpoint E and is tangent at endpoint E, while the other end connects to the outer contour of the secondary cutting edge. This milling insert has a Bézier curve profile, which effectively improves the curvature distribution on the tooth root transition curve when cutting tooth grooves, increases the radius of curvature of the tooth root transition curve, reduces tooth root stress, and thus improves the root strength of involute gears.

Description

Technical Field

[0001] This invention relates to the field of gear machining technology, and in particular to a milling insert and a disc milling cutter. Background Technology

[0002] Disc milling cutters are a commonly used gear forming tool. Through spindle rotation and tooth feed motion, they can efficiently remove gear blank material, thereby completing the milling of gear tooth grooves.

[0003] In order to balance the machining efficiency and accuracy of milling cutters, most gears are machined so that the final tooth root area is close to an arc shape. This results in stress concentration and weak strength at the tooth root, which reduces the durability and safety of the gear.

[0004] Therefore, there is an urgent need to design a milling cutter to solve the above-mentioned problems in the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a milling insert and a disc milling cutter that can improve the curvature distribution at the tooth root of the machined gear, thereby strengthening the tooth root.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] Milling inserts are mounted on the end faces of both sides of a milling cutter head. Each milling insert includes a top cutting edge, a side cutting edge, and a secondary cutting edge. The top cutting edge is positioned between the side cutting edge and the secondary cutting edge. The outer contour of the top cutting edge convexes towards the workpiece to be machined, and the outer contour of the top cutting edge includes:

[0008] The top edge arc, one end of which is connected to the outer contour line of the side edge, and the other end of which is endpoint E;

[0009] A Bézier curve, one end of which is connected to and tangent to the endpoint E, and the other end of which is connected to the outer contour of the secondary cutting edge.

[0010] Preferably, the outer contour of the secondary blade includes a secondary blade straight line and a secondary blade arc. One end of the secondary blade arc is connected to the secondary blade straight line, and the other end of the secondary blade arc is an endpoint F. The end of the Bezier curve away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F.

[0011] Preferably, the central angle A2 corresponding to the secondary blade arc satisfies: 20°≥A2≥1°;

[0012] And / or, the end of the secondary blade arc away from the endpoint F is connected to the endpoint G of the secondary blade straight line and is tangent at the endpoint G.

[0013] Preferably, the top edge arc is tangent to the first external tangent at the endpoint E, the secondary edge arc is tangent to the second external tangent at the endpoint F, the first external tangent and the second external tangent intersect at the intersection point L, data point M is provided on line segment EL, and data point N is provided on line segment FL;

[0014] The endpoint E is the starting point of the Bézier curve, the endpoint F is the ending point of the Bézier curve, and the data point M and the data point N are both control points of the Bézier curve.

[0015] Preferably, line segments ML, NL, and MN enclose a triangle △MNL, and a data point P is set inside the triangle △MNL, which is the control point of the Bézier curve.

[0016] Preferably, the outer contour line of the secondary cutting edge includes a secondary cutting edge straight line, the secondary cutting edge straight line having an endpoint G;

[0017] The two end faces of the milling cutter head are symmetrical about the axis of symmetry Z. The angle b between the extension of the secondary cutting edge line and the axis of symmetry Z satisfies: 20°≥b≥3°. An endpoint F is provided on the extension of the secondary cutting edge line. The end of the Bezier curve away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F.

[0018] Preferably, along the radial direction of the milling cutter head, the top cutting edge arc has a cutting point D closest to the workpiece to be processed, and a circle center O' is provided on the axis of symmetry Z. An auxiliary circle O' passing through the cutting point D and having a radius of DO' is tangent to the extension line of the secondary cutting edge line at the endpoint F.

[0019] Preferably, along the radial direction of the milling cutter head, the top cutting edge arc has a cutting point D closest to the workpiece to be processed, and the central angle A1 corresponding to the arc segment DE satisfies: 30°≥A1≥5°.

[0020] Preferably, the outer contour line of the side blade includes a straight side blade line, and a chamfered arc is provided between the top blade arc and the straight side blade line;

[0021] One end of the chamfered arc is tangent to the top edge arc at connection point C, and the other end of the chamfered arc is tangent to the side edge straight line at connection point B.

[0022] A disc milling cutter includes a milling cutter disc and a plurality of milling inserts as described above. The milling inserts are detachably connected to the milling cutter disc. The milling inserts have a centrally symmetrical structure. The rotation of the milling cutter disc drives the milling inserts to rotate in order to cut the workpiece to be processed.

[0023] The beneficial effects of this invention are as follows:

[0024] The milling insert provided by this invention includes a top cutting edge, a side cutting edge, and a secondary cutting edge. The top cutting edge is disposed between the side cutting edge and the secondary cutting edge. The outer contour of the top cutting edge includes a top cutting edge arc and a Bézier curve. Since the Bézier curve connects the top cutting edge arc and the outer contour of the secondary cutting edge, the milling insert has a Bézier curve contour shape. When cutting tooth grooves, it can effectively improve the curvature distribution on the tooth root transition curve, increase the radius of curvature of the tooth root transition curve, and reduce tooth root stress, thereby improving the tooth root strength of involute gears. At the same time, since the Bézier curve and the top cutting edge arc are connected and tangent at the endpoint E, the outer contour of the top cutting edge is ensured to be smooth and even, thereby ensuring the accuracy of workpiece dimensions during the cutting process.

[0025] The disc milling cutter provided by the present invention includes a milling cutter disc and a plurality of milling inserts as described above. The milling inserts are mounted on the milling cutter disc. The rotation of the milling cutter disc drives the milling inserts to cut the workpiece to be processed, thereby realizing the milling of the workpiece. The disc milling cutter can improve the curvature distribution at the root of the gear teeth being processed, avoid processing arc-shaped tooth roots, thereby improving the root strength and having good practicality. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the outer contour of the milling cutter provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the outer contour of the milling cutter provided in Embodiment 2 of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the disc milling cutter provided in a specific embodiment of the present invention;

[0029] Figure 4 This is a projection view of the milling inserts on both sides of the disc milling cutter provided in a specific embodiment of the present invention.

[0030] In the picture:

[0031] 100-Milling cutter head;

[0032] 1-Top edge arc;

[0033] 2-Bezier curve;

[0034] 3-Secondary edge straight line;

[0035] 4-Secondary cutting edge arc;

[0036] 5-Side edge straight line;

[0037] 6-Chamfered arc. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0042] like Figure 1 and Figure 2As shown, the present invention provides a milling insert, which is mounted on the end faces of both sides of a milling cutter head 100. The milling insert includes a top cutting edge, a side cutting edge, and a secondary cutting edge, with the top cutting edge disposed between the side cutting edge and the secondary cutting edge. The outer contour of the top cutting edge protrudes towards the workpiece to be machined, and the outer contour of the top cutting edge includes a top cutting edge arc 1 and a Bézier curve 2. One end of the top cutting edge arc 1 is connected to the outer contour of the side cutting edge, and the other end of the top cutting edge arc 1 is an endpoint E. One end of the Bézier curve 2 is connected to the endpoint E and is tangent at the endpoint E, and the other end of the Bézier curve 2 is connected to the outer contour of the secondary cutting edge. In this embodiment, since the Bézier curve 2 connects the top cutting edge arc 1 and the outer contour line of the secondary cutting edge, the milling insert has a Bézier curve profile. When cutting the tooth groove, it can effectively improve the curvature distribution on the tooth root transition curve, increase the radius of curvature of the tooth root transition curve, and reduce the tooth root stress, thereby improving the tooth root strength of the involute gear. At the same time, since the Bézier curve 2 and the top cutting edge arc 1 are connected and tangent at the endpoint E, the outer contour line of the top cutting edge is smooth, thereby ensuring the accuracy of the workpiece dimensions during the cutting process.

[0043] like Figure 1 and Figure 2 As shown, the outer contour of the side cutting edge includes a straight side cutting line 5, a top cutting edge arc 1, and a chamfered arc 6 between the straight side cutting line 5 and the top cutting edge arc 1. One end of the chamfered arc 6 is tangent to the top cutting edge arc 1 at connection point C, and the other end of the chamfered arc 6 is tangent to the straight side cutting line 5 at connection point B. In this embodiment, the chamfered arc 6 is a circular arc. The radius and center of the circle containing the chamfered arc 6 need to be determined according to the actual module or size of the workpiece to be processed. It is sufficient to ensure that one end of the chamfered arc 6 is tangent to the top cutting edge arc 1 at connection point C, and the other end is tangent to the straight side cutting line 5 at connection point B.

[0044] like Figure 1 and Figure 2As shown, along the radial direction of the milling cutter head 100, the top cutting edge arc 1 has a cutting point D that is closest to the workpiece to be machined. The central angle A1 corresponding to the arc segment DE satisfies: 30°≥A1≥5°, where the top cutting edge arc 1 is a circular arc and the cutting point D is a point on the circular arc. Therefore, the arc segment DE is a part of the top cutting edge arc 1. In this embodiment, the workpiece to be processed is a cylindrical gear blank, the milling cutter head 100 is a disc-shaped structure, the axis of the milling cutter head 100 is perpendicular to the axis of the workpiece to be processed, and the milling cutter head 100 feeds radially along the workpiece to be processed; the top cutting edge arc 1 is set radially opposite to the axis of the workpiece to be processed, wherein the cutting point D is the endpoint of the top cutting edge arc 1 that is closest to the workpiece to be processed, that is, the endpoint of the workpiece to be processed that is cut first when the milling cutter feeds; after the chamfer arc 6 is determined according to the actual situation of the workpiece to be processed, the top cutting edge arc 1 can be determined by the connection point C where the top cutting edge arc 1 and the chamfer arc 6 are tangent and the top cutting edge arc 1 passes through the cutting point D. The circle in which the top cutting edge arc 1 is located is the first circle O1, and the radius R1 of the first circle O1 can be selected according to the module or size of the workpiece to be processed. After the radius R1 is determined, the central angle A1 is selected as 15°, and the position of the endpoint E can be determined.

[0045] like Figure 3 As shown, the present invention also provides a disc milling cutter, which includes a milling cutter head 100 and a plurality of milling inserts as described above. The milling inserts are detachably connected to the milling cutter head 100 and have a centrally symmetrical structure. The rotation of the milling cutter head 100 drives the milling inserts to rotate in order to cut the workpiece. In this embodiment, the milling inserts are mounted on the milling cutter head 100. The rotation of the milling cutter head 100 drives the milling inserts to cut the workpiece, thereby realizing the milling of the workpiece. This disc milling cutter can improve the curvature distribution at the root of the machined gear teeth, avoid machining arc-shaped tooth roots, thereby improving the tooth root strength and having good practicality. In this embodiment, the milling inserts are mounted on the milling cutter head 100. The rotation of the milling cutter head 100 drives the milling inserts to cut the workpiece, thereby realizing the milling of the workpiece. This disc milling cutter can improve the curvature distribution at the root of the machined gear teeth, avoid machining arc-shaped tooth roots, thereby improving the tooth root strength and having good practicality.

[0046] In this embodiment, the milling insert is bolted to the milling cutter head 100. Since the milling insert has a centrally symmetrical structure, when the side edge, top edge, and secondary edge of one end of the milling insert are worn, the operator can remove the milling insert and replace or maintain it. The milling insert has two symmetrical ends along its length, and the same side edge, top edge, and secondary edge are distributed on each end. Therefore, when the side edge, top edge, and secondary edge of one end of the milling insert are worn, the operator can also remove the milling insert and reverse its direction so that the other end of the milling insert faces the workpiece to be processed in order to cut the workpiece.

[0047] like Figure 3 and Figure 4 As shown, the milling cutter head 100 has a disc-shaped structure, the diameter of which can be selected according to the actual size of the workpiece to be machined. Milling inserts are evenly distributed on both sides of the milling cutter head 100, and the number of milling inserts on both sides is the same and they are staggered along the circumference of the milling cutter head 100; the projections of the milling inserts on both sides are as follows. Figure 4 As shown, the left and right sides of the milling cutter head 100 are symmetrical about the axis of symmetry Z. The milling inserts on both sides can rotate around point O on the axis of symmetry to fine adjust the cutting position and cutting angle (the dashed line represents the milling insert before rotation).

[0048] Example 1

[0049] like Figure 1 As shown, in this embodiment, the outer contour of the secondary blade includes a secondary blade straight line 3 and a secondary blade arc 4. One end of the secondary blade arc 4 is connected to the secondary blade straight line 3, and the other end of the secondary blade arc 4 is endpoint F. The end of the Bézier curve 2 away from endpoint E is connected to endpoint F and is tangent at endpoint F. The two endpoints of the secondary blade straight line 3 are endpoint H and endpoint G, the two endpoints of the secondary blade arc 4 are endpoint G and endpoint F, and the two endpoints of the Bézier curve 2 are endpoint F and endpoint E. It can be understood that the Bézier curve 2 and the secondary blade arc 4 are connected and tangent at endpoint F.

[0050] like Figure 1 As shown, the central angle A2 corresponding to the secondary cutting edge arc 4 satisfies: 20° ≥ A2 ≥ 1°; and / or, the end of the secondary cutting edge arc 4 away from the endpoint F is connected to the endpoint G of the secondary cutting edge straight line 3 and is tangent at the endpoint G. In this embodiment, the secondary cutting edge straight line 3 and the secondary cutting edge arc 4 are connected at the endpoint G, and the secondary cutting edge arc 4 is tangent to the secondary cutting edge straight line 3 at the endpoint G; the secondary cutting edge arc 4 is a circular arc, and the circle it is in is the second circle O2. The radius R2 of the second circle O2 can be selected according to the module or size of the workpiece to be processed. When the radius R2 is determined, the central angle A2 is selected as 10°, and the position of the endpoint F can be determined.

[0051] like Figure 1As shown, the top edge arc 1 is tangent to the first external tangent at endpoint E, and the secondary edge arc 4 is tangent to the second external tangent at endpoint F. The first and second external tangents intersect at intersection point L. Data point M is set on line segment EL, and data point N is set on line segment FL. Endpoint E is the starting point of Bézier curve 2, endpoint F is the ending point of Bézier curve 2, and data points M and N are control points of Bézier curve 2. Specifically, Bézier curve 2 is a common two-dimensional image in the field of mathematics, which can be determined by a starting point, an ending point, and several control points. Its formation principle and derivation process will not be elaborated here. In this embodiment, Bézier curve 2 is determined by four points: endpoint E, endpoint F, data point M, and data point N. Among them, endpoint E is the starting point, endpoint F is the ending point, and data points M and N are two control points, thereby determining the third-order Bézier curve 2.

[0052] To further improve the smoothness of the Bézier curve 2 fitting, thereby enhancing the machining accuracy of the milling insert, such as... Figure 1 As shown, line segments ML, NL, and MN enclose a triangle △MNL. A data point P is located inside triangle △MNL, serving as a control point for Bézier curve 2. In this embodiment, data point P is any point inside triangle △MNL. Bézier curve 2 is determined by five points: endpoint E, endpoint F, data point M, data point N, and data point P, thus forming a fourth-order Bézier curve 2. The equation of Bézier curve 2 is not detailed here.

[0053] In this embodiment, as Figure 1 As shown, the milling insert has a centrally symmetrical structure. One end of the milling insert along its length is sequentially provided with a side cutting edge, a top cutting edge, and a secondary cutting edge, while the other end is symmetrically distributed with secondary cutting edges, a top cutting edge, and a side cutting edge. Therefore, the entire milling insert has two outer contour lines for the side cutting edge, two outer contour lines for the top cutting edge, and two outer contour lines for the secondary cutting edge. Taking the outer contour line of the secondary cutting edge as an example, one endpoint of the outer contour line of the secondary cutting edge connects to the Bézier curve 2 at the same end of the milling insert. The Bézier curve 2 connects to the top cutting edge arc 1 at the same end of the milling insert. The other endpoint of the outer contour line of the secondary cutting edge connects to the straight line 5 of the side cutting edge at the other end of the milling insert, thus forming a complete closed contour line of the milling insert. It can be understood that the two endpoints of the straight line 3 of the secondary cutting edge in the outer contour line of the secondary cutting edge at the other end of the milling insert are endpoint G' and endpoint H', respectively.

[0054] Furthermore, such as Figure 1 As shown, the included angle α between the secondary cutting edge line 3 and the adjacent side cutting edge line 5 is an obtuse angle, and its value range is 179°≥a≥155°; in this embodiment, the included angle α is 160°.

[0055] Example 2

[0056] like Figure 2 As shown, this embodiment provides a milling insert, the structure of which is basically the same as that of the milling insert in Embodiment 1. The main difference is that: the outer contour of the secondary cutting edge includes the secondary cutting edge straight line 3, the secondary cutting edge straight line 3 has an endpoint G; the two end faces of the milling cutter head 100 are symmetrical about the axis of symmetry Z, the angle b between the extension of the secondary cutting edge straight line 3 and the axis of symmetry Z satisfies: 20°≥b≥3°, an endpoint F is provided on the extension of the secondary cutting edge straight line 3, and the end of the Bezier curve 2 away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F. In this embodiment, the milling cutter head 100 has a disc-shaped structure, and the left and right sides of the milling cutter head 100 are symmetrical about the axis of symmetry Z; the secondary cutting line 3 is a straight line segment, one end of the secondary cutting line 3 is the end point H, the secondary cutting line 3 is connected to the side cutting line 5 at an angle through the end point H, the other end of the secondary cutting line 3 continues to extend to the end point F through the end point G, and the angle between the extension of the secondary cutting line 3 and the axis of symmetry Z is 15°, the Bezier curve 2 is connected to and tangent to the extension of the secondary cutting line 3 at the end point F, that is, the end point F is the end of the secondary cutting line 3.

[0057] It is understandable that, such as Figure 2 As shown, the method for determining Bézier curve 2 in this embodiment is the same as that in Embodiment 1, namely: the tangent of the extension line of the secondary cutting edge straight line 3 at endpoint F intersects the first external tangent at intersection point L; data point M is set on line segment EL, and data point N is set on line segment FL; endpoint E is the starting point of Bézier curve 2, endpoint F is the ending point of Bézier curve 2, and data points M and N are both control points of Bézier curve 2, thereby determining the third-order Bézier curve 2. In order to further improve the smoothness of the fitting of Bézier curve 2, thereby improving the machining accuracy of the milling insert, such as... Figure 1 As shown, line segments ML, NL, and MN enclose a triangle △MNL. A data point P is located inside triangle △MNL, serving as a control point for Bézier curve 2. In this embodiment, data point P is any point inside triangle △MNL. Bézier curve 2 is determined by five points: endpoint E, endpoint F, data point M, data point N, and data point P, thus forming a fourth-order Bézier curve 2.

[0058] When determining Bézier curve 2, to facilitate determining the location of endpoint F, such as... Figure 2As shown, along the radial direction of the milling cutter head 100, the top cutting edge arc 1 has a cutting point D closest to the workpiece to be machined. A circle center O' is set on the axis of symmetry Z. An auxiliary circle O' passing through the cutting point D and having a radius of DO' is tangent to the extension of the secondary cutting edge line 3 at the endpoint F. In this embodiment, both the endpoint F and the cutting point D are located on the auxiliary circle O'. The radius R' of the auxiliary circle O' can be selected according to the module or size of the workpiece to be machined. It can be understood that the cutting point D and the endpoint E are points on the top cutting edge arc 1, and both are located on the first circle O1. The radius R1 of the first circle O1 is smaller than the radius R' of the auxiliary circle O'.

[0059] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A milling insert mounted on the end face of both sides of a milling cutter head (100), characterized in that, The milling insert includes a top cutting edge, a side cutting edge, and a secondary cutting edge, wherein the top cutting edge is disposed between the side cutting edge and the secondary cutting edge; the outer contour line of the top cutting edge convexes towards the workpiece to be machined, and the outer contour line of the top cutting edge includes: Top edge arc (1), one end of the top edge arc (1) is connected to the outer contour line of the side edge, and the other end of the top edge arc (1) is endpoint E; Bézier curve (2), one end of which is connected to the endpoint E and is tangent at the endpoint E, and the other end of which is connected to the outer contour line of the secondary blade; The outer contour of the secondary blade includes a secondary blade straight line (3) and a secondary blade arc (4). One end of the secondary blade arc (4) is connected to the secondary blade straight line (3), and the other end of the secondary blade arc (4) is endpoint F. The end of the Bezier curve (2) away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F. The top edge arc (1) is tangent to the first external tangent at the endpoint E, the secondary edge arc (4) is tangent to the second external tangent at the endpoint F, the first external tangent and the second external tangent intersect at the intersection point L, data point M is set on line segment EL, and data point N is set on line segment FL; The endpoint E is the starting point of the Bézier curve (2), the endpoint F is the ending point of the Bézier curve (2), and the data point M and the data point N are both control points of the Bézier curve (2).

2. The cutter blade of claim 1, wherein, The central angle A2 corresponding to the secondary blade arc (4) satisfies: 20°≥A2≥1°; And / or, the end of the secondary blade arc (4) away from the endpoint F is connected to the endpoint G of the secondary blade straight line (3) and is tangent at the endpoint G.

3. The cutter blade of claim 1, wherein, Line segments ML, NL, and MN enclose a triangle MNL, and a data point P is set inside the triangle MNL. The data point P is the control point of the Bézier curve (2).

4. The cutter blade of claim 1, wherein, The outer contour of the secondary blade includes a secondary blade straight line (3), the secondary blade straight line (3) having an endpoint G; The two end faces of the milling cutter head (100) are symmetrical about the axis of symmetry Z. The angle b between the extension of the secondary cutting edge straight line (3) and the axis of symmetry Z satisfies: 20°≥b≥3°. An endpoint F is provided on the extension of the secondary cutting edge straight line (3). The end of the Bezier curve (2) away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F.

5. The cutter blade of claim 4, wherein, Along the radial direction of the milling cutter head (100), the top cutting edge arc (1) has a cutting point D closest to the workpiece to be processed, and a circle center O' is provided on the axis of symmetry Z. An auxiliary circle O' passing through the cutting point D and having a radius of DO' is tangent to the extension of the secondary cutting edge straight line (3) at the endpoint F.

6. The milling insert according to any one of claims 1-5, characterized in that, Along the radial direction of the milling cutter head (100), the top cutting edge arc (1) has a cutting point D closest to the workpiece to be processed, and the central angle A1 corresponding to the arc segment DE satisfies: 30°≥A1≥5°.

7. The milling insert according to any one of claims 1-5, characterized in that, The outer contour of the side blade includes a side blade straight line (5), and a chamfered arc (6) is provided between the top blade arc (1) and the side blade straight line (5). One end of the chamfered arc (6) is tangent to the top edge arc (1) at connection point C, and the other end of the chamfered arc (6) is tangent to the side edge straight line (5) at connection point B.

8. A disc milling cutter, characterized in that, The device includes a milling cutter head (100) and a plurality of milling inserts as described in any one of claims 1-6. The milling inserts are detachably connected to the milling cutter head (100). The milling inserts have a centrally symmetrical structure. The rotation of the milling cutter head (100) drives the milling inserts to rotate in order to cut the workpiece to be processed.

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