A circular double-sided cutting insert and milling tool with anti-rotation structure

Abstract

The application discloses a circular double-sided cutting blade with an anti-rotation structure and a milling cutter. The circumferential side surface of the circular double-sided cutting blade intersects with the upper end surface and the lower end surface to form an upper cutting edge and a lower cutting edge. The circumferential side surface comprises a plurality of radial protruding parts and a plurality of radial recessed parts. The radial protruding parts and the radial recessed parts are alternately arranged along the circumferential direction. The circumferential side surface is an alternating recessed curve and a protruding curve in any radial section of the circular double-sided cutting blade. The radial protruding parts and the radial recessed parts are obliquely arranged along the circumferential side surface. The oblique directions of the radial protruding parts and the radial recessed parts have an angle θ with the axial direction of the circular double-sided cutting blade. The upper end surface is coincident with the projection of the lower end surface in the axial direction after rotating the blade center axis as the center by an angle θ. The blade mounting groove of the milling cutter is correspondingly arranged with the circular double-sided cutting blade. The application has the advantages of convenient mounting and dismounting, stable and reliable positioning, and difficulty in deflection.

Description

Technical Field

[0001] This invention relates to metal cutting tools, and more particularly to a circular double-sided cutting insert and milling tool with an anti-rotation structure. Background Technology

[0002] Typically, round inserts used in milling are single-sided inserts with a positive angle and no anti-rotation structure. These inserts are mounted on the corresponding milling cutter and fixed in the tool holder by a clamping screw. During cutting, the cutting insert is subjected to the reaction forces from the workpiece and chips, thereby generating a rotational torque centered on the axis of the screw hole. This torque may loosen the screw, causing the insert to be loosely clamped, resulting in cutting vibration, which can lead to chipping, reduced lifespan, or even the insert flying out of the tool holder.

[0003] To address the aforementioned issues, existing cutting inserts employ positioning grooves at the bottom or raised or recessed surfaces on the side as positioning surfaces to prevent rotation. For example, Chinese patent document CN114012153A discloses a cutting tool, but this structure is limited to the groove being on the lower or side surface of the insert, making it suitable only for single-sided inserts and resulting in low insert utilization. Chinese patent document CN107538020A discloses a circular insert designed to prevent rotation. This insert has at least one arc-shaped groove on the inner surface of its central hole that mates with the surface of a fastening screw that secures the circular cutting insert. The screw is positioned and prevents rotation by being eccentrically positioned with the insert's screw hole, but this structure is only suitable for single-sided inserts. Chinese patent document CN111788028A discloses another solution, designing a double-sided insert designed to prevent rotation. It uses multiple angled indexing latches protruding from the side as an anti-rotation structure, but this structure mainly has a clearance angle of 0°, meaning it is only suitable for negative angle inserts. Compared to positive angle inserts, negative angle inserts have excessive cutting forces, placing higher demands on the machine tool load and causing excessive impact during the cutting process. In addition, most existing anti-rotation positioning surface designs are mainly based on flat surfaces and vertical protrusions on the side walls. While they can provide positioning, clamping relies entirely on the clamping force of the screws, resulting in poor stability and easy damage. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a circular double-sided cutting insert and milling tool with an anti-rotation structure that is stable and reliable in positioning and not prone to deflection.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A circular double-sided cutting insert with an anti-rotation structure includes an upper end face, a lower end face, and a circumferential side surface connecting the upper and lower end faces. The circular double-sided cutting insert also has a central hole penetrating the upper and lower end faces. The circumferential side surface intersects the upper and lower end faces to form an upper cutting edge and a lower cutting edge, respectively. The circumferential side surface includes multiple radial protrusions and multiple radial recesses, which are alternately arranged circumferentially. The circumferential side surface has alternating concave and convex curves on any radial section of the circular double-sided cutting insert. The radial protrusions and radial recesses are inclined along the circumferential side surface. The inclination directions of the radial protrusions and radial recesses are both at an angle θ with the axial direction of the circular double-sided cutting insert. The upper end face, after rotating by an angle θ around the central axis of the insert, coincides with the projection of the lower end face in the axial direction.

[0007] As a further improvement to the above technical solution:

[0008] The angle θ between the inclination direction of the radial protrusion and the radial recess and the axial direction of the circular double-sided cutting blade satisfies: -45°≤θ≤45°.

[0009] The circumferential side surface forms the back face of the circular double-sided cutting insert. The waistline contour of the circumferential side surface is a curve. The tangent line of the waistline contour has an angle α with the parallel line of the axis of the central hole, and satisfies 0°≤α≤20°.

[0010] The upper cutting edge rotates by an angle θ around the central axis of the blade and then coincides with the projection of the lower cutting edge in the axial direction.

[0011] Both the upper and lower cutting edges are composed of multiple arc segments, which are alternating convex arc segments 4a and concave arc segments 4b. The junction of the convex arc segment 4a and the concave arc segment 4b is tangent. The radius of the convex arc segment 4a is r3, and the radius of the concave arc segment 4b is r4, and the following condition is met: r3≥r4.

[0012] All of the convex arc segments 4a are internally tangent to a circle with radius r1 and concentric with the central hole, and all of the concave arc segments 4b are externally tangent to a circle with radius r2 and concentric with the central hole, and satisfy: r1-r2≥0.5mm.

[0013] The convex arc segment 4a and the concave arc segment 4b are both equidistantly distributed along the circumference of the circular double-sided cutting blade, and the number of the convex arc segment 4a and the concave arc segment 4b is N, where N satisfies: N≥4.

[0014] A milling cutter includes a cutter body and a circular double-sided cutting insert with an anti-rotation structure according to the present invention. The cutter body has an insert mounting groove, and the circular double-sided cutting insert is installed in the insert mounting groove. The insert mounting groove includes a bottom support surface and a side support surface. The side support surface is correspondingly arranged with the circumferential side surface. After the circular double-sided cutting insert is installed in place, the center line of the insert mounting groove is parallel to the axis of the center hole.

[0015] As a further improvement to the above technical solution:

[0016] The blade body has multiple blade mounting slots.

[0017] Compared with the prior art, the advantages of the present invention are as follows:

[0018] The circular double-sided cutting insert with anti-rotation structure of the present invention includes an upper end face, a lower end face, and a circumferential side surface connecting the upper end face and the lower end face. The circular double-sided cutting insert also has a central hole penetrating the upper end face and the lower end face. The circumferential side surface intersects with the upper end face and the lower end face respectively to form an upper cutting edge and a lower cutting edge. The circumferential side surface includes multiple radial protrusions and multiple radial recesses, which are alternately arranged circumferentially. The circumferential side surface has alternating concave and convex curves on any radial section of the circular double-sided cutting insert. The radial protrusions and radial recesses are inclined along the circumferential side surface. The projections of the upper end face and the lower end face in the axial direction coincide. The inclined radial protrusions... The radial recess increases the positioning contact area of ​​the circumferential side surface of the cutting insert. It also generates an axially downward clamping force and a torque force opposite to the rotation direction of the cutting insert during cutting. This effectively prevents the circular double-sided cutting insert from deflecting relative to the tool body during cutting, improving the stability and reliability of the cutting insert's positioning and clamping. The circumferential side surface of the circular double-sided cutting insert has alternating concave and convex curves on any radial section, meaning that both the upper and lower cutting edges are corrugated curve cutting edges. This type of cutting edge has a good chip-breaking effect during cutting, which can effectively improve the distribution of cutting force on the cutting edge and increase the service life of the circular double-sided cutting insert.

[0019] The milling cutter of the present invention includes a cutter body and a circular double-sided cutting insert with an anti-rotation structure. The cutter body has an insert mounting groove, and the circular double-sided cutting insert is installed in the insert mounting groove. The insert mounting groove includes a bottom support surface and a side support surface, and the side support surface is correspondingly arranged with the circumferential side surface. After the circular double-sided cutting insert is installed in place, the center line of the insert mounting groove is parallel to the axis of the center hole. The circular double-sided cutting insert is stably and reliably positioned in the insert mounting groove and is not prone to deflection. Therefore, the milling cutter is easy to assemble and disassemble and has good machining quality and high precision. Attached Figure Description

[0020] Figure 1 This is a perspective view of the circular double-sided cutting blade with an anti-rotation structure according to the present invention.

[0021] Figure 2 This is a front view of the circular double-sided cutting blade with anti-rotation structure of the present invention.

[0022] Figure 3 This is a top view of the circular double-sided cutting blade with anti-rotation structure of the present invention.

[0023] Figure 4 This is a perspective view of the milling tool of the present invention.

[0024] Figure 5 This is a front view of the milling tool of the present invention.

[0025] Figure 6 This is a schematic diagram of the insert mounting groove of the milling tool of the present invention.

[0026] Figure 7 This is a schematic diagram of the circular double-sided cutting insert with anti-rotation structure of the present invention positioned and installed on a milling tool.

[0027] The labels in the diagram represent:

[0028] 1. Upper end face; 2. Lower end face; 3. Circumferential side surface; 31. Radial protrusion; 32. Radial recess; 41. Upper cutting edge; 42. Lower cutting edge; 4a. Convex arc segment; 4b. Concave arc segment; 5. Center hole; 6. Waistline contour line; 7. Tool body; 8. Tool mounting groove; 81. Bottom support surface; 82. Side support surface. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "horizontal", "inner", "outer", "top", "bottom", etc., which indicate orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0031] Figures 1 to 3This invention illustrates an embodiment of a circular double-sided cutting insert with an anti-rotation structure. The insert includes an upper end face 1, a lower end face 2, and a circumferential side surface 3 connecting the upper end face 1 and the lower end face 2. The insert also has a central hole 5 penetrating the upper end face 1 and the lower end face 2. The circumferential side surface 3 intersects the upper end face 1 and the lower end face 2 to form an upper cutting edge 41 and a lower cutting edge 42, respectively. The circumferential side surface 3 includes multiple radial protrusions 31 and multiple radial recesses 32 (e.g., ...). Figure 3 As shown, in this embodiment, there are eight radial protrusions 31 and eight radial recesses 32. The radial protrusions 31 and radial recesses 32 are alternately arranged circumferentially. The circumferential side surface 3 has alternating concave and convex curves on any radial section of the circular double-sided cutting tool. The radial protrusions 31 and radial recesses 32 are inclined along the circumferential side surface 3. The projections of the upper end surface 1 and the lower end surface 2 in the axial direction coincide. The inclined radial protrusions 31 and radial recesses 32 can increase the positioning contact area of ​​the circumferential side surface 3 of the cutting tool, and can also improve the cutting performance during cutting. The insert 2 generates a clamping force in the axial direction downward and a torque force opposite to the rotation direction of the cutting insert 2, which effectively prevents the circular double-sided cutting insert from deflecting relative to the tool body during cutting, and improves the stability and reliability of the cutting insert positioning and clamping. The circumferential side surface 3 has alternating concave and convex curves on any radial section of the circular double-sided cutting insert, that is, the upper cutting edge 41 and the lower cutting edge 42 are both corrugated curve cutting edges. This kind of cutting edge has a good chip-breaking effect during the cutting process, which can effectively improve the distribution of cutting force on the cutting edge and improve the service life of the circular double-sided cutting insert.

[0032] The positioning of the cutting insert 2 mainly relies on the locking action of the fasteners, which press the cutting insert against the bottom support surface and side wall support surface of the tool groove. The radial protrusion 31 and the radial recess 32 can provide a frictional force inclined along the angle θ. This frictional force is decomposed into axial and circumferential frictional forces. The axial frictional force is in the same direction as the clamping force of the fasteners, and the circumferential frictional force can play an anti-rotation role. In order to avoid the circumferential frictional force being too large and affecting the clamping of the screw on the insert, and at the same time affecting the reliability of the insert installation, the angle θ between the inclination direction of the radial protrusion 31 and the radial recess 32 and the axial direction of the circular double-sided cutting insert satisfies: -45°≤θ≤45°. In this embodiment, θ=30°.

[0033] In this embodiment, the circumferential side surface 3 constitutes the back face of the circular double-sided cutting insert. The waistline contour 6 of the circumferential side surface 3 is a curve. The tangent line of the waistline contour 6 has an angle α with the parallel line of the axis of the central hole 5. In order to reduce the cutting force during the cutting process and ensure the edge strength of the circular double-sided cutting insert, so as not to cause the edge strength to drop too much due to the excessive back angle, making it unsuitable for the general roughing application environment of the circular insert, the following condition should be met: 0°≤α≤20°. In this embodiment, α=11°.

[0034] In this embodiment, the upper cutting edge 41 rotates by an angle θ around the central axis of the blade and then coincides with the projection of the lower cutting edge 42 in the axial direction.

[0035] In this embodiment, both the upper cutting edge 41 and the lower cutting edge 42 are composed of multiple arc segments, which are alternating convex arc segments 4a and concave arc segments 4b. The junction of the convex arc segment 4a and the concave arc segment 4b is tangent. The radius of the convex arc segment 4a is r3, and the radius of the concave arc segment 4b is r4, satisfying that r3≥r4. The upper cutting edge 41 and the lower cutting edge 42 are composed of convex arc segments 4a and concave arc segments 4b, which can reduce the machining difficulty of the circular double-sided cutting insert. The convex arc segment 4a plays the main cutting role. The setting of r3≥r4 is because the smaller r3 is, the weaker the strength of the radial protrusion 31. The circular insert is mainly used in the field of roughing, where the cutting edge impact is large. If the radius of the radial protrusion 31 is too small, it will cause a decrease in the cutting edge strength at the radial protrusion 31, which will make the insert more prone to chipping.

[0036] In this embodiment, all convex arc segments 4a are internally tangent to a circle with radius r1 and concentric with the central hole 5, and all concave arc segments 4b are externally tangent to a circle with radius r2 and concentric with the central hole 5. To ensure that the radial recess 32 has sufficient depth and that the circumferential friction can guarantee the anti-rotation function of this structure, the following condition must be met: r1-r2≥0.5mm. In this embodiment, r1-r2=0.8mm.

[0037] In this embodiment, the convex arc segment 4a and the concave arc segment 4b are equidistantly distributed along the circumference of the circular double-sided cutting insert, and the number of the convex arc segment 4a and the concave arc segment 4b is N. The number of the convex arc segment 4a and the concave arc segment 4b affects the number of indexing operations of the insert, that is, the number of usable cutting edges. N satisfies: N≥4, that is, the insert can be indexed at least 4 times, which can improve the cost performance of the insert. In this embodiment, N equals 8.

[0038] Figures 4 to 7An embodiment of the milling tool of the present invention is shown. The milling tool includes a tool body 7 and a circular double-sided cutting insert with an anti-rotation structure as described in the above embodiment. The tool body 7 has a insert mounting groove 8. The circular double-sided cutting insert is installed in the insert mounting groove 8. The insert mounting groove 8 includes a bottom support surface 81 and a side support surface 82. The side support surface 82 is correspondingly arranged with the circumferential side surface 3. After the circular double-sided cutting insert is installed in place, the center line of the insert mounting groove 8 is parallel to the axis of the center hole 5. The circular double-sided cutting insert is stably and reliably positioned in the insert mounting groove 8 and is not prone to deflection. Therefore, the milling tool is easy to assemble and disassemble and has good machining quality and high precision.

[0039] In this embodiment, the blade body 7 has multiple blade mounting slots 8.

[0040] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A circular double-sided cutting insert with anti-rotation structure, comprising an upper end surface (1), a lower end surface (2), and a circumferential side surface (3) connecting the upper end surface (1) and the lower end surface (2), the circular double-sided cutting insert further comprising a central hole (5) extending through the upper end surface (1) and the lower end surface (2), the circumferential side surface (3) intersecting the upper end surface (1) and the lower end surface (2) to form an upper cutting edge (41) and a lower cutting edge (42), respectively, characterized in that: The circumferential side surface (3) comprises a plurality of radial protrusions (31) and a plurality of radial recesses (32), the radial protrusions (31) and the radial recesses (32) are arranged alternately along the circumference, the circumferential side surface (3) is an alternating concave curve and a convex curve in any radial section of the circular double-sided cutting insert, the radial protrusions (31) and the radial recesses (32) are arranged obliquely along the circumferential side surface (3), the oblique directions of the radial protrusions (31) and the radial recesses (32) both have an angle θ with the axial direction of the circular double-sided cutting insert, and the upper end surface (1) coincides with the projection of the lower end surface (2) in the axial direction after rotating by an angle θ about the center axis of the insert.

2. The circular double-sided cutting insert having anti-rotation structure according to claim 1, characterized in that: The angle θ between the oblique directions of the radial protrusions (31) and the radial recesses (32) and the axial direction of the circular double-sided cutting insert satisfies: -45°≤θ≤45°.

3. The circular double-sided cutting insert with anti-rotation structure according to claim 2, characterized in that: The circumferential side surface (3) constitutes the relief surface of the circular double-sided cutting insert, the waist line profile (6) of the circumferential side surface (3) is a curve, the tangent line of the waist line profile (6) and the parallel line of the center hole (5) axis have an angle α, and satisfy 0°≤α≤20°.

4. The circular double-sided cutting insert with anti-rotation structure according to any one of claims 1 to 3, characterized in that: The upper cutting edge (41) coincides with the projection of the lower cutting edge (42) in the axial direction after rotating by an angle θ about the center axis of the insert.

5. The circular double-sided cutting insert with anti-rotation structure according to claim 4, characterized in that: The upper cutting edge (41) and the lower cutting edge (42) are both composed of a plurality of circular arc segments, and are alternately arranged convex circular arc segments (4a) and concave circular arc segments (4b), the convex circular arc segments (4a) and the concave circular arc segments (4b) are tangent at the joint, the radius of the convex circular arc segment (4a) is r3, the radius of the concave circular arc segment (4b) is r4, and satisfy: r3≥r4.

6. The circular double-sided cutting insert with anti-rotation structure according to claim 5, characterized in that: All the convex circular arc segments (4a) are inscribed in a circle with a radius r1 and the same center as the center hole (5), and all the concave circular arc segments (4b) are circumscribed in a circle with a radius r2 and the same center as the center hole (5), and satisfy: r1-r2≥0.5mm.

7. The circular double-sided cutting insert with anti-rotation structure according to claim 5, characterized in that: The convex circular arc segments (4a) and the concave circular arc segments (4b) are equidistantly distributed along the circumference of the circular double-sided cutting insert, and the number of the convex circular arc segments (4a) and the concave circular arc segments (4b) is N, N satisfies: N≥4.

8. A milling tool, characterized by: The tool body (7) is provided with a plurality of insert mounting grooves (8), and the circular double-sided cutting insert with anti-rotation structure according to any one of claims 1 to 7 is arranged in the insert mounting groove (8). The insert mounting groove (8) comprises a bottom support surface (81) and a side support surface (82), the side support surface (82) is arranged correspondingly to the circumferential side surface (3), and the center line of the insert mounting groove (8) is parallel to the axis of the center hole (5) after the circular double-sided cutting insert is mounted in place.

9. The milling tool according to claim 8, characterized in that: The tool body (7) is provided with a plurality of insert mounting grooves (8).

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