A ball-end tool for milling

Abstract

A ball-end tool for milling processing includes a tool arbor, two blades, and two first locking members. The tool arbor is provided with two tool seats. The first locking member passes through the blade and the tool seat to lock the blade to the corresponding tool seat. The blade is provided with a main cutting edge and a sub-cutting edge. The side of the blade where the sub-cutting edge is located is also provided with a sub-positioning plane and a second sub-positioning plane. The bottom surface of the blade is also provided with a first groove. The tool seat is provided with a fixed surface, which is opposite to the bottom surface of the blade and is provided with a second groove. The second groove and the first groove form a locking blind hole. The locking blind hole is provided with a second locking member for locking. The side of the tool seat is also provided with a first side positioning plane and a second side positioning plane. The first side positioning plane is aligned with the first sub-positioning plane, and the second side positioning plane is aligned with the second sub-positioning plane. The present invention adopts a double-screw clamping method to provide sufficient clamping force for the blade, further improve the clamping stability, prevent the blade from loosening, and increase the service life of the blade.

Description

Technical Field

[0001] The invention relates to the field of milling tools, in particular to a ball-end tool used for milling processing. Background Art

[0002] Ball-end milling cutters that process curved surface contours are usually subjected to complex cutting forces during the machining process, and often experience violent vibrations when machining deeper concave cavities or corners. This variable and complex cutting force and violent vibration can cause the blade and cutter body to loosen, resulting in extremely unstable blade force or bending and deformation of the blade clamping screw. Furthermore, the screw may break and the blade may fly out. Especially in the machining process of large-sized tools (tool diameter ≥φ40), the cutting force is greater, and the blade clamping needs to be more stable to avoid the above situation. Therefore, for large-sized ball-end milling cutters, how to stably clamp the ball-end milling insert on the cutter body is very important.

[0003] The invention patent of authorization announcement CN103418823A discloses a milling blade and a matching milling cutter. A groove is set below the cutting edge of the blade. The groove is a triangular pyramid and its bottom opening is located on the bottom surface of the blade; a protrusion that matches the blade groove is set on the base of the milling cutter groove.

[0004] The above patent can reduce the risk of screws breaking due to excessive bending caused by excessive force to a certain extent. However, for large-sized ball-end milling tools (tool diameter ≥φ40), the blade size is large. If the inner surface of the triangular pyramid groove below the cutting edge of the blade is used as one or two positioning surfaces of the blade, the positioning surface area at the groove is too small relative to the blade size, and the raised entity on the milling cutter seat corresponding to the blade groove is too small. When the tool is subjected to large loads during the processing process, the raised surface on the tool seat will be easily deformed or damaged, and there is a risk of the blade loosening.

[0005] In addition, when machining workpieces with curved contours, ball-end milling cutters are subject to complex cutting forces and often experience violent vibrations when machining deep concave cavities or corners. This variable and complex cutting force and violent vibration can cause the blade and cutter body to loosen, resulting in extremely unstable blade force or bending and deformation of the screw. Furthermore, the screw may break and the blade may fly out. In addition, when the clamping force provided by the blade clamping screw is constant (the clamping force provided by the blade clamping screw has an upper limit; if the upper limit is exceeded, the blade clamping screw will break due to excessive bending and deformation), the unit pressure on the positioning surface of the blade decreases, and the unit pressure is insufficient to press the milling blade tightly. During the machining process, the tool holder and the blade are prone to loose fit, resulting in the blade loosening. On the other hand, the machining process of large-scale tools uses larger processing parameters than that of small-scale tools, resulting in increased cutting forces and more violent vibrations, which also requires the milling blade to have a greater clamping force. Summary of the Invention

[0006] The main purpose of the present invention is to overcome the above-mentioned defects in the prior art and propose a ball-end tool for milling processing. For large-size ball-end milling tools (tool diameter ≥φ40), the clamping force of the blade installed on the tool rod can be increased, the blade clamping stability can be improved, the blade can be prevented from loosening, and the blade service life can be increased.

[0007] The present invention adopts the following technical solutions:

[0008] A ball-end tool for milling processing comprises a tool rod, two blades and two first locking pieces, the tool rod is provided with two tool seats, the first locking piece passes through the blade and the tool seat to lock the blade to the corresponding tool seat, characterized in that: the blade is provided with a main cutting edge and a sub-cutting edge, the side surface of the blade where the sub-cutting edge is located is also provided with a first sub-positioning plane and a second sub-positioning plane, and the bottom surface of the blade is also provided with a first groove; the tool seat is provided with a fixing surface, the fixing surface is opposite to the bottom surface of the blade and is provided with a second groove, the second groove and the first groove form a locking blind hole, the locking blind hole is provided with a second locking piece for locking, and the side surface of the tool seat is also provided with a first side positioning plane and a second side positioning plane, the first side positioning plane is in contact with the first sub-positioning plane, and the second side positioning plane is in contact with the second sub-positioning plane.

[0009] Preferably, the sub-cutting edge includes a sub-straight edge and a sub-arc edge, the first sub-positioning plane is located below the position of the sub-straight edge on the side of the blade, and the second sub-positioning plane is located below the position of the sub-arc edge on the side of the blade.

[0010] Preferably, the first groove is close to the first sub-positioning plane and is provided with a first semi-cylindrical concave surface and a first cut-off surface, one end of the first semi-cylindrical concave surface passes through to the side where the female cutting edge is located, and the first cut-off surface is located at the other end of the first semi-cylindrical concave surface and is parallel to the sub-straight edge; the end of the second locking piece presses against the first cut-off surface of the first groove; there is a gap between the external thread surface of the second locking piece and the first semi-cylindrical concave surface, and the gap is 0.05mm-0.3mm.

[0011] Preferably, the second groove is provided with a second semi-cylindrical concave surface and a second cut-off surface, one end of the semi-cylindrical concave surface passes through to the outside of the fixing surface, and the second cut-off surface is located at the other end of the second semi-cylindrical concave surface.

[0012] Preferably, the female cutting edge includes a female straight edge and a female arc edge, and the side of the blade where the female cutting edge is located is also provided with a first female positioning plane and a second female positioning plane; the first groove is close to the second female positioning plane.

[0013] Preferably, the bottom surface of the blade is also provided with a third groove, which is close to the second sub-positioning plane and is provided with a third semi-cylindrical concave surface and a third cut-off surface. One end of the third semi-cylindrical concave surface passes through to the side where the sub-cutting edge is located, and the third cut-off surface is located at the other end of the semi-cylindrical concave surface and is parallel to the main straight edge.

[0014] Preferably, the fixing surface of the tool holder is further provided with a protrusion, which is embedded in the third groove; or the third groove is close to the first female positioning plane.

[0015] Preferably, the nominal diameter of the second locking member is D≤3 mm, the distance the second locking member is higher than the fixing surface of the tool holder is L and satisfies D / 4≤L≤D / 2.

[0016] Preferably, the second locking member is perpendicular to the first locking member.

[0017] Preferably, the two tool seats are respectively located on both sides of the center line of the tool rod, and the fixing surfaces of the two tool seats are oriented in opposite directions.

[0018] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The tool of the present invention is suitable for large-size tools (tool diameter ≥φ40) with a large blade length. The blade is provided with a first sub-positioning plane and a second sub-positioning plane, which respectively fit with the first side positioning plane and the second side positioning plane on the side of the tool holder, and the blade is locked on the tool rod by the first locking screw and the second locking screw to form a cutting tool with a certain spatial installation size. The double-screw clamping method is adopted to provide sufficient clamping force for the blade, further improve the clamping stability, prevent the blade from loosening, and increase the service life of the blade. On the other hand, it can share the force exerted on the first locking screw, reducing the risk of the screw breaking due to excessive bending.

[0020] 2. The tool of the present invention has a semi-cylindrical concave surface for the first groove and the third groove. Compared with other similar square groove structures, the semi-cylindrical concave surface of the present invention can make the main arc edge and the sub-arc edge corresponding to the first groove and the third groove bear a greater cutting load.

[0021] 3. The tool of the present invention has a first groove close to the first sub-positioning plane and is provided with a first semi-cylindrical concave surface and a first cut-off surface, and a second groove is provided with a second semi-cylindrical concave surface and a second cut-off surface. The first cut-off surface is parallel to the sub-straight edge, and the first semi-cylindrical concave surface and the second semi-cylindrical concave surface form a hole for the second locking member to be installed, and the end of the second locking member is against the first cut-off surface. This structure can avoid the presence of an installation gap between the first sub-positioning plane of the blade and the first side positioning plane of the tool holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a front view of the tool of the present invention;

[0023] Figure 2 It is a rear view of the tool of the present invention;

[0024] Figure 3 Schematic diagram of the tool explosion structure of the present invention Figure 1 ;

[0025] Figure 4 Schematic diagram of the tool explosion structure of the present invention Figure 2 ;

[0026] Figure 5 A three-dimensional diagram of a blade according to the present invention;

[0027] Figure 6 A bottom view of the blade of the present invention;

[0028] Figure 7 A schematic diagram of a blade according to the present invention;

[0029] Figure 8 It is a partial front view of the tool of the present invention;

[0030] Figure 9 for Figure 8 The cross-sectional view along line AA;

[0031] Figure 10 This is a schematic diagram of the second locking member of the present invention;

[0032] Among them: 10, tool rod, 11, tool seat, 12, fixed surface, 13, first side positioning plane, 14, second side positioning plane, 15, locking hole, 16, second groove, 16a, second semi-cylindrical concave surface, 16b, second cut-off surface, 17, bump, 18, side, 20, blade, 20a, bottom surface, 21, mother cutting edge, 21a, mother straight edge, 21b, mother arc edge, 22, sub-cutting edge, 22a, sub-straight edge Blade, 22b, sub-arc blade, 23, first mother positioning plane, 24, first sub-positioning plane, 25, second mother positioning plane, 26, second sub-positioning plane, 27, first groove, 27a, first cut-off surface, 27b, first semi-cylindrical concave surface, 28, third groove, 28a, third cut-off surface, 28b, third semi-cylindrical concave surface, 29, locking blind hole, 30, first locking piece, 40, second locking piece, 41, end.

[0033] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0034] The present invention is further described below through specific embodiments.

[0035] In the present invention, the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description, the directions or positional relationships indicated by "upper", "lower", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and are not intended to indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0036] See also Figures 1 to 10A ball-end tool for milling processing includes a tool arbor 10, two blades 20, two first locking members 30 and two second locking members 40. The tool arbor 10 is provided with two tool seats 11, and the two tool seats 11 are respectively located on both sides of the center line of the tool arbor 10. The tool seat 11 is provided with a fixed surface 12 and a side surface 18. The fixed surfaces 12 of the two tool seats 11 face oppositely, for example, the fixed surface 12 of one tool seat 11 faces upward, and the fixed surface 12 of the other tool seat 11 faces downward. The side surfaces 18 of the two tool seats 11 are located on the inner side of the fixed surface 12. The first locking member 30 passes through the blade 20 and the tool seat 11 to lock the blade 20 to the corresponding tool seat 11, that is, the blade 20 and the tool seat 11 are respectively provided with a through locking hole 15, and the first locking member 30 passes through the locking hole 15 to lock the blade 20 to the tool seat 11.

[0037] See also Figure 5-Figure 7 A mother cutting edge 21 and a sub-cutting edge 22 are formed at the junction of the top surface and the side surface of the blade 20 of the present invention. The mother cutting edge 21 and the sub-cutting edge 22 are connected head to tail. When the blade 20 is fixed on the tool holder 11, the mother cutting edge 21 is located on the outside of the fixed surface 12, and the sub-cutting edge 22 is located on the inside of the fixed surface 12.

[0038] Specifically, the parent cutting edge 21 includes a parent linear edge 21a and a parent circular edge 21b, and the child cutting edge 22 includes a child linear edge 22a and a child circular edge 22b. One end of the parent linear edge 21a is connected to one end of the child circular edge 22b, and the other end of the parent linear edge 21a is connected to one end of the parent circular edge 21b; the other end of the parent circular edge 21b is connected to one end of the child linear edge 22a, and the other end of the child linear edge 22a is connected to the other end of the child circular edge 22b, thereby forming a willow leaf shape. In actual application, the lengths of the parent linear edge 21a, parent circular edge 21b, child linear edge 22a, and child circular edge 22b can be set as needed.

[0039] The side surface where the sub-cutting edge 22 of the blade 20 of the present invention is located is further provided with a first sub-positioning plane 24 and a second sub-positioning plane 26. The side surface 18 of the tool holder 11 is also correspondingly provided with a first side positioning plane 13 and a second side positioning plane 14. The first side positioning plane 13 is aligned with the first sub-positioning plane 24, and the second side positioning plane 14 is aligned with the second sub-positioning plane 26. Specifically, the first sub-positioning plane 24 is located below the position of the sub-straight edge 22a on the side surface of the blade 20, that is, the surface between the sub-straight edge 22a and the bottom surface 20a of the blade 20 is a plane and serves as the first sub-positioning plane 24. The first side positioning plane 13 and the first sub-positioning plane 24 on the tool holder 11 can be the same size and shape. The second sub-positioning plane 26 is located below the sub-arc edge 22b on the side of the blade 20, that is, the surface between the sub-arc edge 22b and the bottom surface 20a of the blade 20 is provided with a second sub-positioning plane 26. The second side positioning plane 14 on the tool holder 11 can be adapted to the size and shape of the second sub-positioning plane 26, and the area of ​​the first sub-positioning plane 24 can be larger than the area of ​​the second sub-positioning plane 26.

[0040] The side of the blade 20 where the mother cutting edge 21 of the present invention is located is also provided with a first mother positioning plane 23 and a second mother positioning plane 25. The first mother positioning plane 23 is located below the position of the mother straight edge 21a on the side of the blade 20, and the second mother positioning plane is located below the position of the mother arc edge 21b on the side of the blade 20.

[0041] The blade 20 of the present invention is provided with a first sub-positioning surface 24 and a second sub-positioning surface 26 which respectively fit in with the first side positioning surface 13 and the second side positioning surface 14 on the side surface 18 of the blade seat 11 .

[0042] The bottom surface 20a of the blade 20 is provided with a first groove 27, and the fixed surface 12 of the tool holder 11 is opposite to the bottom surface 20a of the blade 20 and is provided with a second groove 16. The second groove 16 and the first groove 27 form a locking blind hole 29. The locking blind hole 29 is provided with a second locking member 40 for locking. The second locking member 40 is perpendicular to the first locking member 30. The nominal diameter of the second locking member 40 is D≤3mm. The distance L between the second locking member 40 and the fixed surface 12 of the tool holder 11 satisfies D / 4≤L≤D / 2. On the basis of locking the blade 20 with the first locking member 30, the present invention adds a second locking member 40 to perform secondary locking on the first sub-positioning plane 24 of the blade 20 from the bottom surface 20a of the blade 20, providing sufficient clamping force for the blade 20, improving the clamping stability, preventing the blade 20 from loosening, and increasing the service life of the blade 20. On the other hand, it can share the force exerted on the first locking member 30, reducing the risk of the first locking member 30 breaking due to excessive bending.

[0043] Specifically, the first groove 27 is located near the first sub-positioning plane 24 and is provided with a first semi-cylindrical concave surface 27b and a first cut-off surface 27a. One end of the first semi-cylindrical concave surface 27b extends to the side where the main cutting edge 21 is located, that is, the position of the main arc edge 21b. The first cut-off surface 27a is located at the other end of the first semi-cylindrical concave surface 27b, that is, near the side where the sub-cutting edge 22 is located. The first cut-off surface 27a is also parallel to the sub-straight edge 22a. The second groove 16 on the tool holder 11 has the same shape as the first groove 27 and is also provided with a second semi-cylindrical concave surface 16a and a second cut-off surface 16b. One end of the second semi-cylindrical concave surface 16a extends to the outside of the fixed surface 12 of the tool holder 11, and the second cut-off surface 16b is located at the other end of the second semi-cylindrical concave surface 16a, that is, near the side surface 18 of the tool holder 11. The first semi-cylindrical concave surface 27b and the second semi-cylindrical concave surface 16a are connected to form a hole.

[0044] The second locking member 40 of the present invention has an external thread, and the locking blind hole 29 has an internal thread. When the second locking member 40 is locked in the locking blind hole 29, the end of the second locking member 40 presses against the first cut-off surface 27a of the first groove 27. A gap of 0.05 to 0.3 mm exists between the external threaded surface of the second locking member 40 and the first semi-cylindrical concave surface 27b.

[0045] Furthermore, the bottom surface 20a of the blade 20 is also provided with a third groove 28. This third groove 28 is adjacent to the second sub-positioning plane 26 and is provided with a third semi-cylindrical concave surface 28b and a third cut-off surface 28a. One end of the third semi-cylindrical concave surface 28b extends to the side where the sub-cutting edge 22 is located, i.e., where the sub-end arc edge is located. The third cut-off surface 28a is located at the other end of the semi-cylindrical concave surface and is parallel to the main straight edge 21a. The fixed surface 12 of the tool holder 11 is also provided with a protrusion 17, which is embedded in the third groove 28. The function of the protrusion 17 is to limit the range of movement of the blade before it is locked, thereby improving the clamping accuracy and stability.

[0046] The first and third grooves 27 and 28 of the present invention utilize semi-cylindrical concave surfaces, which open toward the fixed surface 12 of the tool holder 11 and have a semicircular cross-section. Compared to other similar square groove structures, the semi-cylindrical concave surfaces of the present invention utilize an arched structure, which allows the primary and secondary arcuate cutting edges 21b and 22b corresponding to the first and second grooves 27 and 16 to withstand greater cutting loads.

[0047] In the present invention, because the fixing surfaces 12 of the two tool seats 11 face in different directions, in order to allow the insert 20 to be installed on any tool seat 11, a first female positioning plane 23 and a second female positioning plane 25 are also provided on the side of the insert 20 where the female cutting edge 21 is located, and two grooves, namely a first groove 27 and a third groove 28, are provided on the tool seat 11. The first groove 27 is close to the second female positioning plane 25, and the third groove 28 is close to the first female positioning plane 23. Assuming that when the insert is removed from the first tool seat and installed in the second tool seat, the female cutting edge 21 located on the outside of the first tool seat becomes located on the inside of the second tool seat and becomes the sub-cutting edge 22, then the third groove 28 located in the first tool seat and the second groove 16 on the second tool seat form a locking blind hole 29.

[0048] The blade material of the present invention can be made of one or more materials such as high-speed steel, cemented carbide, CBN, PCD, etc. The tool installation process of the invention is as follows:

[0049] Place the blade 20 on the corresponding tool holder 11, pass the first locking member 30 through the locking hole 15 and use a torque wrench to lock it, and set the torque value to 0.5N. Then the first locking member 30 passes through the locking hole 15 to slightly lock the blade 20 on the tool holder 11. At this time, the blade 20 is in a pre-tightened state, that is, the blade 20 can still move slightly; use a torque wrench to adjust the second locking member 40, set the torque value to 0.5N, lock the second locking member 40 into the locking blind hole 29, and the second locking member 40 pushes the first cut-off surface 27a of the first groove 27 of the blade 20, so that the first sub-positioning plane 24 and the first side positioning plane 13 of the tool holder 11 are slightly fitted. At this time, the blade 20 is in a pre-tightened state; finally, lock the first locking member 30 and the second locking member 40 respectively. The use of the second locking member 40 can provide sufficient clamping force for the blade 20, improve the clamping stability, prevent the blade 20 from loosening, and increase the service life of the blade 20. It can also share the force exerted on the first locking member 30, reduce the risk of the first locking member 30 breaking due to excessive bending, and completely avoid the existence of an installation gap at the first sub-positioning plane 24 of the blade 20.

[0050] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A ball-end tool for milling, comprising a tool arbor, two blades, and two first locking members, wherein the tool arbor is provided with two tool holders, and the first locking members pass through the blades and the tool holders to lock the blades to the corresponding tool holders, characterized in that: The blade is provided with a main cutting edge and a sub-cutting edge, and the side surface of the blade where the sub-cutting edge is located is also provided with a first sub-positioning plane and a second sub-positioning plane, and the bottom surface of the blade is also provided with a first groove; the tool holder is provided with a fixing surface, and the fixing surface is opposite to the bottom surface of the blade and is provided with a second groove, and the second groove and the first groove form a locking blind hole, and the locking blind hole is provided with a second locking piece for locking, and the side surface of the tool holder is also provided with a first side positioning plane and a second side positioning plane, the first side positioning plane is in contact with the first sub-positioning plane, and the second side positioning plane is in contact with the second sub-positioning plane.

2. A ball-end tool for milling according to claim 1, characterized in that: The sub-cutting edge includes a sub-straight edge and a sub-arc edge. The first sub-positioning plane is located below the position of the sub-straight edge on the side of the blade, and the second sub-positioning plane is located below the position of the sub-arc edge on the side of the blade.

3. A ball end tool for milling according to claim 2, characterized in that: The first groove is close to the first sub-positioning plane and is provided with a first semi-cylindrical concave surface and a first cut-off surface. One end of the first semi-cylindrical concave surface passes through to the side where the female cutting edge is located. The first cut-off surface is located at the other end of the first semi-cylindrical concave surface and is parallel to the sub-straight edge; the end of the second locking piece presses against the first cut-off surface of the first groove; there is a gap between the external thread surface of the second locking piece and the first semi-cylindrical concave surface, and the gap is 0.05mm-0.3mm.

4. A ball end tool for milling according to claim 1, characterized in that: The second groove is provided with a second semi-cylindrical concave surface and a second cut-off surface. One end of the semi-cylindrical concave surface passes through to the outside of the fixing surface, and the second cut-off surface is located at the other end of the second semi-cylindrical concave surface.

5. The ball end tool for milling according to claim 1, characterized in that: The mother cutting edge includes a mother straight edge and a mother arc edge. The side of the blade where the mother cutting edge is located is also provided with a first mother positioning plane and a second mother positioning plane; the first groove is close to the second mother positioning plane.

6. A ball end tool for milling according to claim 5, characterized in that: The bottom surface of the blade is also provided with a third groove, which is close to the second sub-positioning plane and is provided with a third semi-cylindrical concave surface and a third cut-off surface. One end of the third semi-cylindrical concave surface passes through to the side where the sub-cutting edge is located, and the third cut-off surface is located at the other end of the semi-cylindrical concave surface and is parallel to the main straight edge.

7. A ball end tool for milling according to claim 6, characterized in that: The fixing surface of the tool holder is further provided with a protrusion, which is embedded in the third groove; or the third groove is close to the first female positioning plane.

8. The ball end tool for milling according to claim 1, characterized in that: The nominal diameter of the second locking member is D≤3 mm, the distance L by which the second locking member is higher than the fixing surface of the knife seat satisfies D / 4≤L≤D / 2.

9. The ball end tool for milling according to claim 1, characterized in that: The second locking member is perpendicular to the first locking member.

10. The ball end tool for milling according to claim 1, characterized in that: The two knife seats are respectively located on both sides of the center line of the knife rod, and the fixing surfaces of the two knife seats are oriented in opposite directions.

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