Gear milling insert and disc cutter

Abstract

The application belongs to the technical field of gear machining, and discloses a gear milling blade and a disc-shaped milling cutter. The gear milling blade comprises a side blade, a top blade and a sub-blade, and the top blade is arranged between the side blade and the sub-blade. The outer contour line of the top blade is convex to a workpiece to be machined, and the outer contour line of the top blade comprises a top blade arc line and an elliptical arc line. One end of the top blade arc line is connected with the outer contour line of the side blade, and the other end of the top blade arc line is an end point E. One end of the elliptical arc line is connected with the end point E and is tangent to the end point E at the end point E, and the other end of the elliptical arc line is connected with the outer contour line of the sub-blade. The gear milling blade has an elliptical profile curve, which can effectively improve the curvature distribution on the dedendum transition curve, increase the curvature radius of the dedendum transition curve and reduce the dedendum stress when cutting the gear slot, so as to improve the dedendum strength of the involute gear. Meanwhile, since the elliptical arc line is connected with the top blade arc line at the end point E and is tangent to the top blade arc line at the end point E, the outer contour line of the top blade is smooth and smooth.

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] To balance machining efficiency and accuracy, disc milling cutters are widely used in the machining of large-module gears. Because the cutting inserts of the milling cutter have an arc-shaped structure, the final tooth root area of ​​most gears is nearly arc-shaped after machining, leading to stress concentration and weak strength at the tooth root, thus reducing the gear's durability and safety. Furthermore, in low-speed, heavy-load transmission applications, multi-planetary gear structures are commonly used to improve load-bearing capacity; however, the tooth root strength of the gear ring in this type of structure is typically weak.

[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] A milling insert, comprising 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:

[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] An elliptical arc, one end of which is connected to and tangent to endpoint E, and the other end of which is connected to the outer contour line of the secondary blade.

[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 endpoint F. The end of the elliptical arc away from endpoint E is connected to endpoint F and is tangent at 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 cutting edge arc away from the endpoint F is connected to the endpoint G of the secondary cutting edge 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, and the length of EL is equal to the length of FL.

[0014] Preferably, the elliptical arc has a focus M1 and a focus M2, and the line connecting the focus M1 and the focus M2 is parallel to the line connecting the endpoint E and the endpoint F.

[0015] Preferably, the outer contour of the secondary blade includes a secondary blade straight line with an endpoint G. The top blade arc is tangent to the first external tangent line at the endpoint E. The first external tangent line intersects the extension of the secondary blade straight line at the intersection point L. An endpoint F is provided on the extension of the secondary blade straight line. The end of the elliptical arc away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F. The length of EL is equal to the length of FL.

[0016] Preferably, along the radial direction of the workpiece to be processed, 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°.

[0017] 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;

[0018] 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.

[0019] A disc milling cutter includes a milling cutter disc and a plurality of milling inserts as described above. The milling inserts are connected to the milling cutter disc, and the rotation of the milling cutter disc drives the milling inserts to rotate in order to cut the workpiece to be processed.

[0020] Preferably, the milling insert has a centrally symmetrical structure and is detachably connected to the milling cutter head.

[0021] The beneficial effects of this invention are as follows:

[0022] 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 an elliptical arc. Since the elliptical arc connects the top cutting edge arc and the outer contour of the secondary cutting edge, the milling insert has an elliptical contour curve. 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 the involute gear. At the same time, since the elliptical arc and the top cutting edge arc are connected and tangent at the endpoint E, the outer contour of the top cutting edge is smooth, thus ensuring the accuracy of the workpiece dimensions during the cutting process.

[0023] 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

[0024] Figure 1 This is a schematic diagram of the outer contour of the milling cutter provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the outer contour of the milling insert provided in Embodiment 2 of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the disc milling cutter provided in a specific embodiment of the present invention;

[0027] 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.

[0028] In the picture:

[0029] 100-Milling cutter head;

[0030] 1-Top edge arc;

[0031] 2-Elliptical arc;

[0032] 3-Secondary edge straight line;

[0033] 4-Secondary cutting edge arc;

[0034] 5-Side edge straight line;

[0035] 6-Chamfered arc. Detailed Implementation

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] like Figure 1 and Figure 2As shown, this invention provides a milling insert, which 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 convexes towards the workpiece to be machined. The outer contour of the top cutting edge includes a top cutting edge arc 1 and an elliptical arc 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 endpoint E. One end of the elliptical arc 2 is connected to endpoint E and tangent at endpoint E, and the other end of the elliptical arc 2 is connected to the outer contour of the secondary cutting edge. In this embodiment, since the elliptical arc 2 connects the top cutting edge arc 1 and the outer contour of the secondary cutting edge, the milling insert has an elliptical contour curve. 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, reduce tooth root stress, and thus improve the tooth root strength of the involute gear. At the same time, since the elliptical arc 2 and the top cutting edge arc 1 are connected and tangent at endpoint E, the outer contour of the top cutting edge is ensured to be smooth, thereby ensuring the accuracy of the workpiece dimensions during the cutting process.

[0041] 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.

[0042] like Figure 1 and Figure 2 As shown, along the radial direction of the workpiece to be processed, the top cutting edge arc 1 has a cutting point D that is closest to the workpiece to be processed. 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 top cutting arc 1 is set radially opposite to the axis of the workpiece to be processed. The cutting point D is the endpoint of the top cutting arc 1 that is closest to the workpiece to be processed, which 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 arc 1 can be determined by the connection point C where the top cutting arc 1 and the chamfer arc 6 are tangent and the top cutting arc 1 passes through the cutting point D. The circle in which the top cutting arc 1 is located is the first circle. The radius R1 of the first circle 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° to determine the position of the endpoint E.

[0043] like Figure 3As shown, the present invention also provides a disc milling cutter, which includes a cutter head 100 and a plurality of milling inserts as described above. The milling inserts are connected to the cutter head 100, and the rotation of the 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 cutter head 100, and the rotation of the 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.

[0044] To further improve the practicality and extend the service life of the disc milling cutter, the milling insert has a centrally symmetrical structure and is detachably connected to the milling cutter head 100. In this embodiment, the milling insert is bolted to the milling cutter head 100. 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 for replacement or maintenance. The milling insert has symmetrical ends along its length, with the same side edge, top edge, and secondary edge 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 orientation so that the other end of the milling insert faces the workpiece to be machined for cutting the workpiece.

[0045] 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 milling inserts on both sides 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, there is an axis of symmetry between the two milling cutters. The milling cutters on both sides are symmetrical about this axis of symmetry. Both milling cutters 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 cutter before rotation).

[0046] Example 1

[0047] like Figure 1 As shown, in this embodiment, the outer contour line 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 elliptical arc 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 elliptical arc 2 are endpoint F and endpoint E. It can be understood that the elliptical arc 2 and the secondary blade arc 4 are connected and tangent at endpoint F.

[0048] like Figure 1As 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 a second circle. The radius R2 of the second circle 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.

[0049] like Figure 1 As 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, and the length of line segment EL is equal to the length of line segment FL. In this embodiment, the top edge arc 1 has a first external tangent, which is tangent to the top edge arc 1 at endpoint E. The secondary edge arc 4 has a second external tangent, which is tangent to the secondary edge arc 4 at endpoint F. The first and second external tangents intersect at intersection point L, and the length of line segment EL is equal to the length of line segment FL.

[0050] like Figure 1 As shown, elliptical arc 2 has foci M1 and M2, and the line connecting foci M1 and M2 is parallel to the line connecting endpoint E and endpoint F. In this embodiment, elliptical arc 2 is a part of ellipse M1M2, where M1 and M2 are the two foci of the ellipse. Ellipse M1M2 is tangent to endpoint E and endpoint F, respectively, and the line connecting foci M1 and M2 is parallel to line segment EF.

[0051] Specifically, let the length of line segment EF be 2v, the distance between line segment M1M2 and line segment EF be u, and ∠ELF be 2θ. Then the formulas for calculating the major axis radius a and minor axis radius b of ellipse M1M2 are as follows:

[0052] ;

[0053] .

[0054] In this embodiment, as Figure 1As shown, the milling insert has a centrally symmetrical structure. One end of the milling insert along its length is provided with a side cutting edge, a top cutting edge, and a secondary cutting edge in sequence, while the other end is symmetrically distributed with a secondary cutting edge, a top cutting edge, and a side cutting edge. Therefore, the entire milling insert has two outer contour lines of the side cutting edge, two outer contour lines of the top cutting edge, and two outer contour lines of the secondary cutting edge. Taking the outer contour line of the secondary cutting edge as an example, it is explained as follows: one end of the outer contour line of the secondary cutting edge is connected to the elliptical arc 2 at the same end of the milling insert, the elliptical arc 2 is connected to the top cutting edge arc 1 at the same end of the milling insert, and the other end of the outer contour line of the secondary cutting edge is connected to the straight line 5 of the side cutting edge at the other end of the milling insert, thus forming a complete and closed outline of the milling insert.

[0055] 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°.

[0056] Example 2

[0057] like Figure 2 As shown, this embodiment provides a milling insert. The structure of the milling insert is basically the same as that of the milling insert in Embodiment 1. The main difference is that: the outer contour line 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 top cutting edge arc 1 is tangent to the first external tangent line at the endpoint E, the first external tangent line intersects the extension line of the secondary cutting edge straight line 3 at the intersection point L, the extension line of the secondary cutting edge straight line 3 has an endpoint F, the end of the elliptical arc 2 away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F, and the length of EL is equal to the length of FL.

[0058] In this embodiment, the secondary cutting line 3 is a straight line segment. One end of the secondary cutting line 3 is the endpoint H, and the other end extends from the endpoint G to the endpoint F. The two endpoints of the elliptical arc 2 are the endpoint E and the endpoint F, respectively. The elliptical arc 2 and the secondary cutting line 3 are connected and tangent at the endpoint F, that is, the endpoint F is the end of the secondary cutting line 3. The top cutting arc 1 has a first external tangent line, which is tangent to the top cutting arc 1 at the endpoint E. The extension of the secondary cutting line 3 intersects the first external tangent line at the intersection point L. A point is made on the line segment LH such that the distance between this point and the intersection point L is equal to the length of the line segment EL. This point is the endpoint F.

[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, 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; Elliptical arc (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 the endpoint F. The end of the elliptical arc (2) away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F. 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.

2. The milling insert according to claim 1, characterized in that, 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, and the length of EL is equal to the length of FL.

3. The milling insert according to claim 1, characterized in that, The elliptical arc (2) has a focus M1 and a focus M2, and the line connecting the focus M1 and the focus M2 is parallel to the line connecting the endpoint E and the endpoint F.

4. The milling insert according to any one of claims 1-3, characterized in that, Along the radial direction of the workpiece to be processed, the top cutting edge arc (1) has a cutting point D that is closest to the workpiece to be processed, and the central angle A1 corresponding to the arc segment DE satisfies: 30°≥A1≥5°.

5. The milling insert according to any one of claims 1-3, 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.

6. A milling insert, 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; An elliptical arc (2) is formed, with one end connected to and tangent to endpoint E, and the other end connected to the outer contour line of the secondary blade. The outer contour of the secondary blade includes a secondary blade straight line (3), the secondary blade straight line (3) has an endpoint G, the top blade arc (1) is tangent to the first external tangent at the endpoint E, the first external tangent intersects the extension of the secondary blade straight line (3) at the intersection point L, the extension of the secondary blade straight line (3) has an endpoint F, the end of the elliptical arc (2) away from the endpoint E is connected to the endpoint F and is tangent at the endpoint F, and the length of EL is equal to the length of FL.

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

8. The milling insert according to claim 6, 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.

9. 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 1-8, wherein the milling inserts are connected to the milling cutter head (100), and the rotation of the milling cutter head (100) causes the milling inserts to rotate in order to cut the workpiece to be processed.

10. The disc milling cutter according to claim 9, characterized in that, The milling insert has a centrally symmetrical structure and is detachably connected to the milling cutter head (100).

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