Ball end cutter with a limiting structure

Abstract

The application discloses a ball end cutter with a limiting structure and belongs to the field of metal cutting processing, which comprises a ball end blade, a matched cutter body and a locking screw. The ball end blade is formed with a first main cutting edge, a second main cutting edge, a tool tip and a screw through hole, and two assembly sides of the ball end blade are respectively formed with an upper open positioning part and a lower open positioning part. The matched cutter body comprises two cutter holders, a screw counterbore and a tool shank, and the two cutter holders are respectively provided with an upper limiting part and a lower limiting part. The locking screw is respectively threadedly connected with the screw through hole and the screw counterbore. The application fixes the installation direction between the ball end blade and the matched cutter body to be axial, so that the radial displacement of the ball end blade is limited. The ball end blade and the matched cutter body are matched in a wedge-shaped pressing mode through the limiting structures on the two sides in opposite directions, and the axial clamping is more reliable under the locking force of the locking screw.

Description

Technical Field

[0001] The invention belongs to the field of metal cutting, and in particular relates to a ball-end tool with a limiting structure. Background Art

[0002] In the field of metal cutting, especially in the cutting of medium and large molds and parts such as automotive mold covers and impellers, the use of single-piece precision milling ball end mills has become very common, and is often used for processing methods such as surface processing, cavity processing and groove processing. Due to its excellent performance in processing stability, processing accuracy and processing efficiency, it is often used in the end process belonging to the category of precision machining. This means that the cutting allowance reserved in the previous process is small and the surface accuracy of the parts is required to be higher. In high-speed cutting, if the tool size is not maintained well or is accompanied by vibration, it will have a great impact on the accuracy of the workpiece. At the very least, the workpiece will be unqualified and need to be repaired, and at worst, the workpiece will be scrapped. Limiting the displacement of the blade in the tool holder can solve the above problems to varying degrees.

[0003] Patent publication number CN110899800A discloses a replaceable single-cutting blade precision milling ball-end cutter. By cooperating with two convex arc positioning surfaces at the bottom of the blade and two concave arc positioning surfaces on the cutter body, the radial displacement, axial displacement and circumferential displacement of the blade in the tool groove can be limited.

[0004] In this scheme, the contact area of ​​the convex arc positioning surface used for positioning is limited. When the blade is statically installed, it cannot provide sufficient guidance and initial positioning for the blade, which can easily lead to improper axial and radial installation. When the blade is subjected to cutting force, the arc positioning surface tends to move relative to the positioning surface of the tool body, resulting in a certain degree of loss in the support force of the tool body on the blade, thereby insufficiently restricting the radial displacement, axial displacement and circumferential displacement of the blade in the tool groove. Summary of the Invention

[0005] The object of the present invention is to provide a ball-end tool with a limiting structure to solve the problems raised in the above-mentioned prior art.

[0006] Provided is a ball-end tool with a limiting structure, comprising:

[0007] A ball-end insert, wherein two working sides of the ball-end insert respectively form a first main cutting edge and a second main cutting edge, the first main cutting edge and the second main cutting edge extend toward an end different from the assembly direction of the ball-end insert and intersect to form a cutting tip, and two assembly sides of the ball-end insert respectively form an upper open positioning portion and a lower open positioning portion, and the upper open positioning portion is adjacent to the second main cutting edge, and the lower open positioning portion is adjacent to the first main cutting edge, and portions of the two assembly sides of the ball-end insert different from the upper open positioning portion and the lower open positioning portion penetrate each other to form a screw through hole;

[0008] A matching knife body, which includes two knife clamps, a screw countersunk hole and a knife handle, wherein the two knife clamps are arranged oppositely and formed on the knife handle, and the screw countersunk hole is formed by two through holes that penetrate the two knife clamps oppositely. One of the knife clamps is provided with an upper limit portion that fits with the upper open positioning portion, and the other knife clamp is provided with a lower limit portion that fits with the lower open positioning portion;

[0009] A locking screw is threadedly connected to the screw through hole and the screw countersunk hole to match the ball head blade with the matching cutter body.

[0010] As a further embodiment of the present invention: the ball-end blade includes an upper surface, a lower surface and a side peripheral surface, the upper surface and the lower surface are connected and transitioned through the side peripheral surface, the upper surface includes an upper end positioning surface, an upper open positioning portion and a first front cutting edge that form an elevation difference with each other, the lower surface includes a lower end positioning surface, a lower open positioning portion and a second front cutting edge that form an elevation difference with each other, the side peripheral surface includes a side positioning surface, a first back angle surface and a second back angle surface, the first back angle surface is adjacent to the lower open positioning portion, the second back angle surface is adjacent to the upper open positioning portion, the first main cutting edge is formed by the intersection of the first front cutting edge and the first back angle surface, and the second main cutting edge is formed by the intersection of the second front cutting edge and the second back angle surface.

[0011] As a further embodiment of the present invention: the upper open positioning portion is a groove structure that is recessed inward relative to the upper end positioning surface, the lower open positioning portion is a groove structure that is recessed inward relative to the lower end positioning surface, the upper limit portion is a boss structure that fits with the upper open positioning portion, and the lower limit portion is a boss structure that fits with the lower open positioning portion.

[0012] As a further embodiment of the present invention: the inner wall portion of the tool handle located between the two tool clamps is a side clamping surface, the opposite surfaces of the two tool clamps are respectively an upper clamping surface and a lower clamping surface, the side positioning surface and the side clamping surface can fit each other, and the intersection parts of the side clamping surface with the upper clamping surface and the lower clamping surface are recessed toward the interior of the tool handle.

[0013] As a further embodiment of the present invention: the upper open positioning portion includes a small bevel and a large bevel, the small bevel intersects with the large bevel to form an intersection line, the extension line of the ball head blade passing through the tip and parallel to the center axis of the matching blade body is the center axis of the ball head blade, the center axis of the screw through hole is perpendicular to the center axis of the ball head blade, the center axis of the screw through hole and the extension line of the intersection line form two projection lines on the radial plane of the center axis of the screw through hole, and an angle of α is formed between the two projection lines, and the angle α is 15°~45°.

[0014] As a further embodiment of the present invention: the lower open positioning portion includes a small bevel and a large bevel, the small bevel and the large bevel intersect to form an intersection line, the extension line of the ball head blade passing through the tip and parallel to the center axis of the matching blade body is the center axis of the ball head blade, the center axis of the screw through hole is perpendicular to the center axis of the ball head blade, the center axis of the screw through hole and the extension line of the intersection line form two projection lines on the radial plane of the center axis of the screw through hole, and an angle of α is formed between the two projection lines, and the angle α is 15°~45°.

[0015] As a further embodiment of the present invention: taking the central axis of the ball-end blade as the rotation axis, the upper open positioning portion and the lower open positioning portion are rotationally symmetrical on the rotation axis.

[0016] As a further embodiment of the present invention: taking the central axis of the ball-end insert as the rotation axis, the first main cutting edge and the second main cutting edge are rotationally symmetrical on the rotation axis.

[0017] As a further embodiment of the present invention: in the direction of the central axis extending from the screw through hole to the tool tip, the large inclined surface is inclined upward along this direction, and the inclination angle is 0.05° to 0.5°.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention creates interference between the upper open positioning portion of the ball-end insert and the upper limit portion of one tool holder, and between the lower open positioning portion of the ball-end insert and the lower limit portion of the other tool holder. This forces the installation direction between the ball-end insert and the matching cutter body to be fixed axially, thereby limiting radial displacement of the ball-end insert. The ball-end insert and the matching cutter body are press-fitted by opposing limit structures on both sides, and the axial clamping is more reliable under the locking force of the locking screw.

[0020] 2. During the initial insertion of the ball-end insert into the toolholder, the upper and lower open positioning sections guide the insert axially for installation, providing guidance and initial positioning for the insert, improving installation efficiency and fit accuracy. Furthermore, during installation, the structure on the tool body avoids the main cutting edge and tip of the ball-end insert, providing a certain degree of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0022] Figure 1 FIG. A is a perspective view of a ball-end insert provided by the present invention;

[0023] Figure 2 FIG. B is a perspective view of a ball-end insert provided by the present invention;

[0024] Figure 3 is a front view of the ball-end insert provided by the present invention;

[0025] Figure 4 This is a bottom view of the ball-end insert provided by the present invention;

[0026] Figure 5 yes Figure 4 A cross-sectional view of the middle blade G position;

[0027] Figure 6 yes Figure 4 A cross-sectional view of the middle blade F position;

[0028] Figure 7 yes Figure 4 A cross-sectional view of the middle blade at position E;

[0029] Figure 8 This is an assembly diagram of the ball-end tool provided by the present invention;

[0030] Figure 9 This is an exploded view of the structure of the ball-end tool provided by the present invention;

[0031] Figure 10 yes Figure 9 Side view of the exploded view;

[0032] Figure 11 It is a three-dimensional diagram of the matching knife body provided by the present invention;

[0033] Figure 12 It is a side view of the matching tool provided by the present invention.

[0034] In the figure: 1. Ball-end insert; 2. Locking screw; 3. Matching tool body; 4. Upper surface; 5. Lower surface; 6. Side positioning surface; 7. Screw through hole; 8. First clearance angle surface; 9. Second clearance angle surface; 10. Side peripheral surface; 11. First main cutting edge; 12. Second main cutting edge; 13. Tool tip; 14. Small bevel; 15. Large bevel; 16. Intersection line; 18. Tool holder; 19. Screw countersunk hole; 20. Tool holder; 21. Upper clamping surface; 22. Lower clamping surface; 23. Side clamping surface; 31. Upper limit portion; 32. Lower limit portion; 41. Upper end positioning surface; 42. Upper open positioning portion; 43. First rake face; 51. Lower end positioning surface; 52. Lower open positioning portion; 53. Second rake face. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0036] Obviously, the drawings described below are merely examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without inventive effort. Furthermore, it is understood that while the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the disclosure of the present invention, any design, manufacturing, or production changes based on the technical content disclosed in the present invention are merely conventional technical means and should not be construed as an inadequacy of the disclosure of the present invention.

[0037] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of substantially identical structures may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Furthermore, the drawings and the following description are provided to facilitate a thorough understanding of the present invention by those skilled in the art and are not intended to limit the subject matter recited in the claims.

[0038] See also Figures 1-12As shown, the ball-end tool with a limiting structure in the embodiment of the present invention includes a ball-end insert 1, a matching cutter body 3 and a locking screw 2. The two working sides of the ball-end insert 1 respectively form a first main cutting edge 11 and a second main cutting edge 12, and the first main cutting edge 11 and the second main cutting edge 12 extend to an end different from the assembly direction of the ball-end insert 1 and intersect to form a cutting tip 13. The two assembly sides of the ball-end insert 1 respectively form an upper open positioning portion 42 and a lower open positioning portion 52, and the upper open positioning portion 42 is adjacent to the second main cutting edge 12, and the lower open positioning portion 52 is adjacent to the first main cutting edge 11. The parts of the two assembly sides of the ball-end insert 1 that are different from the upper open positioning portion 42 and the lower open positioning portion 52 penetrate each other to form a screw through hole 7. The matching blade body 3 includes two blade clamps 18, a screw countersunk hole 19, and a blade handle 20. The two blade clamps 18 are arranged oppositely and formed on the blade handle 20. The screw countersunk hole 19 is formed by two through-holes extending through the two blade clamps 18. One blade clamp 18 is provided with an upper limit portion 31 that abuts the upper open positioning portion 42, and the other blade clamp 18 is provided with a lower limit portion 32 that abuts the lower open positioning portion 52. The locking screw 2 is threadedly connected to the screw through-hole 7 and the screw countersunk hole 19 respectively to mate the ball-end blade 1 with the matching blade body 3.

[0039] See also Figure 9 As shown, when installing a ball-end insert 1 with a matching cutter body 3, the insert 1 can be inserted between two toolholders 18 in a variety of directions, such as along the cutter body's rotational axis, radially perpendicular to the cutter body's rotational axis, and at various other angles. Because the space between the toolholders 18 of this type of cutter body is relatively narrow, the fit between the ball-end insert 1 and the toolholders 18 requires high precision, and manual installation can result in multiple failed insertion attempts.

[0040] During non-axial installation, the main cutting edge on the ball-end insert 1 will first enter the tool holder 18, and the possibility of collision between the main cutting edge and the tool holder 18 will increase, causing a hard-to-find notch in the main cutting edge of the ball-end insert 1. As the cutting process progresses, the notch will worsen, affecting the machining accuracy of the workpiece and reducing the service life of the tool. The solution of the present invention forces the installation direction of the ball-end insert 1 to be fixed axially, thereby limiting the radial displacement of the ball-end insert 1. At the same time, the installation process avoids the first main cutting edge 11, the second main cutting edge 12, and the tip 13 on the ball-end insert 1, providing a certain degree of protection for the main cutting edge and the tip 13, and reducing the chance of damage to the main cutting edge.

[0041] The ball-end insert 1 includes an upper surface 4, a lower surface 5, and a lateral surface 10, with the upper surface 4 and the lower surface 5 connected and transitioning via the lateral surface 10. The upper surface 4 includes an upper end positioning surface 41, an upper open positioning portion 42, and a first rake face 43, which form an elevation difference with each other. The lower surface 5 includes a lower end positioning surface 51, a lower open positioning portion 52, and a second rake face 53, which form an elevation difference with each other. The lateral surface 10 includes a side positioning surface 6, a first clearance angle surface 8, and a second clearance angle surface 9.

[0042] The present invention has two embodiments. The first solution: the upper open positioning portion 42 is a groove structure that is recessed inward relative to the upper end positioning surface 41, the lower open positioning portion 52 is a groove structure that is recessed inward relative to the lower end positioning surface 51, the upper limit portion 31 is a boss structure that fits with the upper open positioning portion 42, and the lower limit portion 32 is a boss structure that fits with the lower open positioning portion 52. The second solution: the upper open positioning portion 42 is a boss structure that extends outward relative to the upper end positioning surface 41, the lower open positioning portion 52 is a boss structure that extends outward relative to the lower end positioning surface 51, the upper limit portion 31 is a groove structure that fits with the upper open positioning portion 42, and the lower limit portion 32 is a groove structure that fits with the lower open positioning portion 52. The above two solutions can solve the technical problems of the present invention, and the present invention preferably adopts the first solution.

[0043] The upper locating surface 41 and the lower locating surface 51 are two parallel surfaces ground on a double-end surface grinder. They cooperate with the toolholder 18 to limit the vertical normal displacement of the ball-end insert 1 within the toolholder 18, perpendicular to the upper locating surface 41 and the lower locating surface 51. The screw hole 7 is a straight hole that passes through and is perpendicular to the upper locating surface 41 and the lower locating surface 51.

[0044] See also Figure 4 As shown, the extension line of the ball-end blade 1 passing through the blade tip 13 and parallel to the central axis of the matching blade body 3 is the central axis A of the ball-end blade 1, and the central axis of the screw through hole 7 is perpendicular to the central axis of the ball-end blade 1. In the two planes of the upper end positioning surface 41 and the lower end positioning surface 51, the central axis A divides the ball-end blade 1 into two left and right parts. Any part rotated along the central axis A by a multiple of a straight angle will coincide with the other part, which means that the upper open positioning portion 42 of the ball-end blade 1 rotates along the central axis A by a straight angle to coincide with the lower open positioning portion 52. The rotationally symmetrical structure ensures that the force between the ball-end blade 1 and the matching tool 3 remains balanced during high-speed rotary cutting operations, avoiding eccentric loads that affect the service life of the ball-end blade 1.

[0045] Among them, see Figure 4As shown, the lower open positioning portion 52 includes a small bevel 14 and a large bevel 15. The small bevel 14 and the large bevel 15 intersect to form an intersection line 16. The intersection line 16 is confined between the side positioning surface 6 and the first relief angle surface 8. The extension of the center axis A and the intersection line 16 forms two projection lines on a radial plane of the center axis of the screw through hole 7. The two projection lines form an angle α between them, and the angle α is between 15° and 45°.

[0046] The purpose of limiting the aforementioned angle α is to prevent the friction of the locking screw 2 or external cutting forces from causing the ball-end insert 1 to rotate about the locking screw 2. This technical solution requires a large bevel 15 with as large an area as possible to ensure sufficient axial compression of the insert, making the compression of the ball-end insert 1 more reliable while also reducing fatigue damage to the locking screw 2. A small bevel 14 is required to be as long as possible to provide resistance to the circumferential displacement of the ball-end insert 1. Whether rotating clockwise or counterclockwise, the ball-end insert 1 will experience resistance from the interaction between the small bevel 14 and the boss of the lower limit portion 32 of the toolholder 18. This, in conjunction with the side locating surface 6, limits the circumferential displacement of the ball-end insert 1 to the greatest extent possible. The preferred angle α is 20°.

[0047] See also Figure 4-Figure 7 As shown, the large bevel 15 slopes upward along the central axis extending from the screw through hole 7 toward the blade tip 13. The large bevel 15 transitions to the lower end positioning surface 51 via the small bevel 14, with a height difference h between the large bevel 15 and the lower end positioning surface 51. The large bevel 15 slopes upward along the central axis A toward the blade tip 13, i.e., h1 < h2 < h3.

[0048] It should be noted that the structural arrangement and arrangement principle of the small inclined surface 14, large inclined surface 15, and intersection line 16 of the upper open positioning portion 42 correspond to those of the lower open positioning portion 52, and will not be described in detail here. Preferably, the structural arrangement of the upper open positioning portion 42 and the lower open positioning portion 52 is the same.

[0049] See also Figure 10-12As shown, during the axial installation of the ball-end insert 1, the upper and lower stop portions 31, 32 within the toolholder 18 gradually engage with the upper and lower open positioning portions 42, 52, respectively. The upper and lower open positioning portions 42, 52 feature inclined large bevels 15 that, in conjunction with the upper and lower stop portions 31, 32, create a wedge-shaped clamping action. This, under the tightening force of the locking screw 2, provides more reliable axial clamping. Simultaneously, as the locking screw 2 continues to tighten, it compresses the ball-end insert 1, forcing the side locating surfaces 6 to mate more closely with the side clamping surfaces 23. This also increases the reaction force exerted on the locking screw 2 by the ball-end insert 1. The presence of the inclined large bevels 15 limits the continued tightening of the locking screw 2, ensuring proper contact between the side locating surfaces 6 and the side clamping surfaces 23, and reducing the risk of fatigue fracture of the locking screw 2 due to excessive tightening force. The inclination angle of the large bevels 15 is 0.05° to 0.5°.

[0050] The ball-end insert 1 has two main cutting edges: a first main cutting edge 11 and a second main cutting edge 12. Rotating either main cutting edge by a straight angle along the central axis A will cause it to overlap with the other main cutting edge. Therefore, it is important to maintain the consistency of the two main cutting edges as much as possible. This ensures that the ball-end insert 1 is subjected to uniform force during alternating cutting operations between the first and second main cutting edges 11, 12.

[0051] The inner wall portion of the tool holder 20 located between the two tool holders 18 is a side clamping surface 23. The opposing surfaces of the two tool holders 18 are an upper clamping surface 21 and a lower clamping surface 22, respectively. The side positioning surface 6 and the side clamping surface 23 can fit together, and the intersection of the side clamping surface 23 with the upper clamping surface 21 and the lower clamping surface 22 is recessed into the interior of the tool holder 20. The upper clamping surface 21 is provided with an upper limit portion 31, and the lower clamping surface 22 is provided with a lower limit portion 32. The space between the two tool holders 18 is used to install the ball-end insert 1, providing support for the ball-end insert 1. The ball-end insert 1 is connected to the matching cutter body 3 via a locking screw 2.

[0052] The inwardly recessed structure ensures that when the ball-end insert 1 is assembled with the matching cutter body 3, the tool holder 18 is slightly deformed, reducing interference caused by machining errors and ensuring smooth assembly. At the same time, it prevents local stress from being generated at the corner of the side clamping surface 23 when the ball-end insert 1 is cutting.

[0053] When the ball-end insert 1 is axially installed, the upper clamping surface 21 aligns with the upper end positioning surface 41 and the upper open positioning portion 42, the lower clamping surface 22 aligns with the lower end positioning surface 51 and the lower open positioning portion 52, and the side clamping surface 23 aligns with the side positioning surface 6. The locking screw 2 locks the ball-end insert 1 to the matching cutter body 3 through the screw countersunk hole 19 and the screw through hole 7. The tool holder 20 is installed on the machine tool system. After locking, the tool rotates at high speed around the rotation axis B, and the tool can be used for cutting the workpiece.

[0054] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the present invention, other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A ball-end tool with a limiting structure, characterized in that: include: A ball-end insert (1), wherein two working sides of the ball-end insert (1) respectively form a first main cutting edge (11) and a second main cutting edge (12), the first main cutting edge (11) and the second main cutting edge (12) extend toward an end different from the assembly direction of the ball-end insert (1) and intersect to form a cutting tip (13), the two assembly sides of the ball-end insert (1) respectively form an upper open positioning portion (42) and a lower open positioning portion (52), and the upper open positioning portion (42) is adjacent to the second main cutting edge (12), and the lower open positioning portion (52) is adjacent to the first main cutting edge (11), and portions of the two assembly sides of the ball-end insert (1) different from the upper open positioning portion (42) and the lower open positioning portion (52) penetrate each other to form a screw through hole (7); A matching knife body (3) comprises two knife clamps (18), a screw countersunk hole (19) and a knife handle (20), wherein the two knife clamps (18) are arranged oppositely and formed on the knife handle (20), the screw countersunk hole (19) is formed by two through holes that penetrate the two knife clamps (18) oppositely, an upper limit portion (31) that fits with the upper open positioning portion (42) is provided on one of the knife clamps (18), and a lower limit portion (32) that fits with the lower open positioning portion (52) is provided on the other knife clamp (18); A locking screw (2) is threadedly connected to the screw through hole (7) and the screw countersunk hole (19) to match the ball head blade (1) with the matching blade body (3).

2. The ball-end tool with a limiting structure according to claim 1, characterized in that: The ball-end insert (1) comprises an upper surface (4), a lower surface (5) and a side circumferential surface (10); the upper surface (4) and the lower surface (5) are connected and transitioned via the side circumferential surface (10); the upper surface (4) comprises an upper end positioning surface (41), an upper open positioning portion (42) and a first rake face (43) which form a height difference with each other; the lower surface (5) comprises a lower end positioning surface (51), a lower open positioning portion (52) and a second rake face (53) which form a height difference with each other ), the side peripheral surface (10) includes a side positioning surface (6), a first back angle surface (8) and a second back angle surface (9), the first back angle surface (8) is adjacent to the lower open positioning portion (52), the second back angle surface (9) is adjacent to the upper open positioning portion (42), the first main cutting edge (11) is formed by the intersection between the first front cutting surface (43) and the first back angle surface (8), and the second main cutting edge (12) is formed by the intersection between the second front cutting surface (53) and the second back angle surface (9).

3. The ball-end tool with a limiting structure according to claim 2, characterized in that: The upper open positioning portion (42) is a groove structure that is recessed inward relative to the upper end positioning surface (41); the lower open positioning portion (52) is a groove structure that is recessed inward relative to the lower end positioning surface (51); the upper limit portion (31) is a boss structure that fits with the upper open positioning portion (42); and the lower limit portion (32) is a boss structure that fits with the lower open positioning portion (52).

4. The ball-end tool with a limiting structure according to claim 2, characterized in that: The inner wall portion of the tool handle (20) located between the two tool clamps (18) is a side clamping surface (23), and the opposite surfaces of the two tool clamps (18) are an upper clamping surface (21) and a lower clamping surface (22), respectively. The side positioning surface (6) and the side clamping surface (23) can fit each other, and the intersection of the side clamping surface (23) with the upper clamping surface (21) and the lower clamping surface (22) is recessed toward the interior of the tool handle (20).

5. The ball-end tool with a limiting structure according to claim 1, characterized in that: The upper open positioning portion (42) includes a small bevel (14) and a large bevel (15), the small bevel (14) and the large bevel (15) intersect to form an intersection line (16), the extension line of the ball-end blade (1) passing through the blade tip (13) and parallel to the central axis of the matching blade body (3) is the central axis of the ball-end blade (1), the central axis of the screw through hole (7) is perpendicular to the central axis of the ball-end blade (1), the central axis of the screw through hole (7) and the extension line of the intersection line (16) form two projection lines on the radial plane of the central axis of the screw through hole (7), and the two projection lines form an angle of α degrees between the two projection lines, and the angle α is 15° to 45°.

6. The ball-end tool with a limiting structure according to claim 1, characterized in that: The lower open positioning portion (52) includes a small bevel (14) and a large bevel (15), the small bevel (14) and the large bevel (15) intersect to form an intersection line (16), the extension line of the ball-end blade (1) passing through the blade tip (13) and parallel to the central axis of the matching blade body (3) is the central axis of the ball-end blade (1), the central axis of the screw through hole (7) is perpendicular to the central axis of the ball-end blade (1), the central axis of the screw through hole (7) and the extension line of the intersection line (16) form two projection lines on the radial plane of the central axis of the screw through hole (7), and the two projection lines form an angle of α degrees, and the angle α is 15° to 45°.

7. A ball-end tool with a limiting structure according to claim 5 or 6, characterized in that: The central axis of the ball-end blade (1) is used as a rotation axis, and the upper open positioning portion (42) and the lower open positioning portion (52) are rotationally symmetrical on the rotation axis.

8. The ball-end tool with a limiting structure according to claim 5 or 6, characterized in that: The central axis of the ball-end insert (1) is used as a rotation axis, and the first main cutting edge (11) and the second main cutting edge (12) are rotationally symmetrical on the rotation axis.

9. The ball-end tool with a limiting structure according to claim 5 or 6, characterized in that: In the direction of extension of the central axis from the screw through hole (7) to the knife tip (13), the large inclined surface (15) is inclined upward along the direction, and the inclination angle is 0.05° to 0.5°.

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