Cutter for machining tail of shaft head

Abstract

A cutter for machining the tail of a shaft head comprises a cylindrical cutter body, a cutter handle coaxially corresponding to the cutter body is arranged at the tail end of the cutter body, a cutter head coaxially corresponding to the cutter body is arranged at the top end of the cutter body, the cutter body, the cutter head and the cutter handle are integrally formed, a side plane parallel to the axis of the cutter handle is arranged on the front side wall of the cutter handle, and the tail end of the side plane extends to the tail face of the cutter handle. The top end of the tool bit is provided with a plurality of tool steps corresponding to the stepped holes in the tail portion of the shaft head, and each tool step is provided with a corresponding cutting edge. According to the utility model, one-step forming of stepped hole processing is realized, the step hole processing procedures are reduced, and the stepped hole processing precision and quality are improved.

Description

Technical Field

[0001] This utility model belongs to the field of drilling tools for machining, and particularly relates to a composite drilling tool for machining stepped irregular holes at the head and tail of a shaft. Background Technology

[0002] The axle head is a key component connecting the front axle to the steering knuckle. As an irregularly shaped part, the customer designed a stepped bore at its rear end to improve the overall system rigidity of the axle. Stepped bores often involve multiple diameter variations. Using traditional machining tools not only makes the machining process cumbersome, requiring the changing of various tools for different bore diameters, which increases positioning errors, but also increases the length-to-diameter ratio of the tool needed for machining small-diameter sections at greater depths. This can easily lead to vibration and runout during machining, resulting in bore diameter deviations or surface roughness. Therefore, using traditional tools, the significant positioning errors and vibration deviations both affect the accuracy and quality of the stepped bore, thus increasing the overall difficulty and cost of axle head machining. Utility Model Content

[0003] The purpose of this utility model is to provide a special composite drill bit for machining stepped irregular holes at the head and tail of a shaft, so as to solve the technical problem that traditional machining tools have a significant impact on the accuracy of machining stepped holes at the head of a shaft.

[0004] To achieve the above objectives, the specific technical solution of this utility model is as follows:

[0005] A cutting tool for machining the head and tail of a shaft includes a cylindrical tool body, a coaxial corresponding tool holder at the tail end of the tool body, and a coaxial corresponding cutting head at the top end of the tool body. The tool body, cutting head, and tool holder are integrally formed. The front side wall of the tool holder has a side plane parallel to its axis and extending to the tail end of the tool holder. The top end of the cutting head has multiple cutting steps corresponding to the stepped hole at the tail end of the shaft, and each cutting step has a corresponding cutting edge.

[0006] Furthermore, the stepped hole at the tail of the shaft head includes three coaxial hole steps: an inner hole, an outer hole, and a chamfered hole. The cutting edge on the cutting head includes a first cutting edge, a second cutting edge, and a third cutting edge arranged sequentially from the top of the cutting head to its tail and corresponding to each other on the same axis. The three cutting edges correspond sequentially to the inner hole, outer hole, and chamfered hole of the stepped hole. The cutting edge corresponding to each cutting edge is located on its top surface. The radial dimension radiated by the cutting edge on each cutting edge is greater than the radial dimension of its step surface and is equal to the radial step surface dimension of the corresponding hole step.

[0007] Furthermore, the cutting edge includes a top cutting edge on the top surface of the first cutting step, a middle cutting edge on the top surface of the second cutting step, and a tail cutting edge on the top surface of the third cutting step. Two corresponding inner grooves are provided on opposite sides of the sidewall of the cutting head. The top of the inner groove extends through to the top surface of the cutting head, and the tail end extends to the middle of the third cutting step. The two inner grooves radially divide the corresponding ends of the cutting head into two opposing fixing blocks along the circumferential direction. The two fixing blocks are connected at the axis of the cutting head. Each fixing block has at least one side as a mounting surface. The cutting edge is located at the connection between the mounting surface and the top surface of the corresponding cutting step, and it extends along the axis toward the top of the corresponding cutting step surface.

[0008] Furthermore, the inner groove includes a first groove located on the rear side of the upper end of the cutter head and a second groove located on the front side of the lower end of the cutter head. The fixing block in front of the first groove is the first fixing block, and the surface on the first fixing block corresponding to the first groove is its mounting surface. The fixing block behind the second groove is the second fixing block, and the surface on the second fixing block corresponding to the second groove is its mounting surface. Both the first and second mounting surfaces are provided with multiple mounting slots corresponding to each cutter step. Each mounting slot is provided with a detachably fixed blade. The cutting edge of the blade is located at the connection between the mounting surface and the step surface of the corresponding cutter step, which is the cutting edge of the cutter head.

[0009] Furthermore, the upper surface of the second fixing block corresponding to the first cutting step is an inclined surface that gradually slopes downward from the tail to the top along the first mounting surface, with the top end lower than the axis of the cutting head. The mounting groove includes a first groove, a second groove, a third groove, a fourth groove, and a fifth groove. The first groove is located at the lower end of the top side of the first mounting surface, and a top core cutter is installed inside it. The second groove is located at the top of the second mounting surface, and a top peripheral cutter is installed inside it. The cutting edges of the top peripheral cutter and the top peripheral cutter correspond to the inner and outer rings of the inner hole, respectively, and the two together form a complete top cutting edge. The third groove is located on the first mounting surface corresponding to the second cutting step, and a middle cutting edge is installed inside it. The fourth groove is located on the second mounting surface corresponding to the second cutting step, and a middle cutting edge is installed inside it. The cutting edges of the middle cutting edge and the middle cutting edge are both middle cutting edges. The fifth groove is located on the second mounting surface corresponding to the third cutting step, and a tail cutting edge is installed inside it. The cutting edge of the tail cutting edge is the tail cutting edge.

[0010] Furthermore, the distance from the upper end of the top circumferential cutting edge to the cutting head axis is not greater than the distance from the upper end of the top core cutting edge to the cutting head axis. The bottom end of the top circumferential cutting edge is lower than the sidewall of the corresponding first cutting step, and its distance to the cutting head axis corresponds to the radius of the inner hole of the stepped hole. The radial dimensions of the first and second middle cutting edges correspond to the difference between the radial dimensions of the outer and inner holes, and the distance from the inner end of both cutting edges to the cutting head axis is less than the distance from the bottom end of the top circumferential cutting edge to the cutting head axis. The radial dimension of the tail cutting edge corresponds to the difference between the maximum inner diameter of the chamfered hole and the inner diameter of the outer hole. The distance from the bottom end of the tail cutting edge to the cutting head axis is greater than the radial dimension of the chamfered hole, and the distance from its upper end to the cutting head axis is less than the distance from the outer end of the middle cutting edge to the cutting head axis.

[0011] Furthermore, the axial projection distance from the cutting edge of the top core cutter and the top peripheral cutter to the cutting edge of the first and second intermediate cutters is the same as the depth difference from the inner hole and the outer hole to the end face of the shaft. The axial projection distance from the cutting edge of the first and second intermediate cutters to the cutting edge of the tail cutter is the same as the depth difference from the outer hole and the chamfered hole to the end face of the shaft.

[0012] Furthermore, the inner end of the outer hole is provided with a coaxial transition step, the two ends of which are respectively connected to the inner end of the outer hole and the outer end of the inner hole. Its sidewall is a trumpet shape that gradually moves away from the axis at a 60° angle from the inside to the outside. The middle cutting edge corresponding to the outer hole is set as an inclined shape that is corresponding to the transition step and gradually moves away from the axis of the cutting head at a 60° angle from its top to its tail.

[0013] Furthermore, the angle between the sidewall of the chamfered hole and its axis is 45°, and the corresponding tail cutting edge is set to be inclined at 45° from the top to the tail, gradually moving away from the axis of the cutting head.

[0014] This utility model relates to a special tool for machining stepped holes at the head and tail of a shaft. Through the cooperation of multiple tool stages, it achieves one-time forming of the stepped hole, reducing the number of machining steps, minimizing positioning errors that may result from multiple tool changes, improving the accuracy and quality of the stepped hole machining, making the machining of stepped holes simpler and faster, reducing the scrap rate of shaft head machining, increasing the overall machining speed and efficiency of the shaft head, and reducing its production cost. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model;

[0016] Figure 2 This utility model Figure 1 Rear view;

[0017] Figure 3 This utility model Figure 1 A magnified view of the left side;

[0018] Figure 4 This utility model Figure 1 A cross-sectional view along the AA direction;

[0019] Figure 5 This is a schematic diagram of the internal structure of the shaft head and tail of this utility model;

[0020] The markings in the diagram are as follows: 1. Cutting head; 11. First cutting step; 12. Second cutting step; 13. Third cutting step; 14. First groove; 15. Second groove; 16. First fixing block; 17. Second fixing block; 18. First mounting surface; 19. Second mounting surface; 2. Cutting body; 3. Cutting shank; 4. Shaft head; 41. Inner hole; 42. Outer hole; 43. Chamfered hole; 44. Transition step; 5. Top cutting edge; 51. Middle cutting edge; 52. Tail cutting edge; 53. Top core cutter; 54. Top peripheral cutter; 55. Middle first cutter; 56. Middle second cutter; 57. Tail cutter. Detailed Implementation

[0021] To better understand the purpose, structure, and function of this utility model, the following description, in conjunction with the accompanying drawings, provides a more detailed description of a cutting tool for machining the head and tail of a shaft.

[0022] like Figure 1-5 As shown, the tool for machining the tail end of the shaft head of this utility model includes a tool body 2, a tool head 1, and a tool holder 3. The tool body 2 is cylindrical, and the tool head 1 and the tool holder 3 are respectively located at both ends of the tool body 2. Both are coaxial with the tool body 2. The tool body 2, the tool head 1, and the tool holder 3 are integrally formed and fixedly connected. In this embodiment, the tool holder 3 is located at the tail end of the tool body 2, and the tool head 1 is located at the top end of the tool body 2. When in use, the tool is fixedly installed externally through the tool holder 3. The front side wall of the tool holder 3 is provided with a side plane parallel to its axis. The tail end of the side plane extends to the tail face of the tool holder 3. The side plane provides guidance and positioning when the tool holder 3 is installed externally. The top end of the tool head 1 is provided with multiple cutting steps corresponding to the stepped hole at the tail end of the shaft head 4. Each cutting step is provided with a corresponding cutting edge. During operation, the tool drills the tail end of the shaft head 4. The stepped hole is machined in one step through the mutual cooperation of the corresponding cutting edges on the multiple cutting steps.

[0023] Furthermore, the stepped hole at the tail of the shaft head 4 includes three steps: a coaxial inner hole 41, an outer hole 42, and a chamfered hole 43. The chamfered hole 43 is formed by the transition chamfer between the sidewall of the outer hole 42 and the tail face of the shaft head 4. The cutting edge on the cutter head 1 corresponds to the steps of the stepped hole, including a first cutting edge 11, a second cutting edge 12, and a third cutting edge 13 arranged sequentially from the top of the cutter head 1 to its tail. These three cutting edges are coaxial and correspond sequentially to the inner hole 41, the outer hole 42, and the chamfered hole 43 of the stepped hole. The cutting edges corresponding to the tool steps are all located on their top surfaces, which facilitates the cutting of the corresponding hole steps. During operation, the tool rotates around its axis, which in turn drives the cutting edges to rotate around its axis, thereby achieving the purpose of cutting the shaft head 4 in the forward direction of the tool head 1. When the tool rotates, the radial dimension radiated by the cutting edge on each tool step is greater than the radial dimension of its step surface, and is equal to the radial step surface dimension of the corresponding hole step. In this way, the tool steps can fully radiate the transverse cross section of the corresponding hole step, so as to drill and shape the hole step in one go during operation.

[0024] Furthermore, the cutting edge includes a top cutting edge 5, a middle cutting edge 51, and a tail cutting edge 52. The top cutting edge 5 is located on the top surface of the first cutting step 11, the middle cutting edge 51 is located on the top surface of the second cutting step 12, and the tail cutting edge 52 is located on the top surface of the third cutting step 13. The axial projection distance between the top cutting edge 5 and the middle cutting edge 51 is the same as the axial projection distance between the top surface of the inner hole 41 and the top surface of the outer hole 42. The axial projection distance between the middle cutting edge 51 and the tail cutting edge 52 is the same as the axial projection distance between the top surface of the outer hole 42 and the top of the chamfered hole 43. Two corresponding inner grooves are provided on the side wall of the cutter head 1, located on opposite sides of the side wall of the cutter body 2. The tops of both inner grooves extend to the top surface of the cutter head 1. The tail end extends to the middle of the third cutting step 13. The two inner grooves radially divide the corresponding ends of the cutter head 1 into two opposing fixed blocks along the circumferential direction. The two fixed blocks are connected at the axis of the cutter head 1. They are integrally formed and fixedly connected. Each fixed block has at least one side as a mounting surface. Each cutting edge is located at the connection between the mounting surface and the top surface of the corresponding cutting step. The top cutting edge 5 is located at the connection between the top surface of the first cutting step 11 and the mounting surface, the middle cutting edge 51 is located at the connection between the second cutting step 12 and the mounting surface, and the tail cutting edge 52 is located at the connection between the third cutting step 13 and the mounting surface. Each cutting edge extends along the axis to the top of the corresponding cutting step surface, which facilitates cutting the shaft head 4 during operation.

[0025] Furthermore, the two inner grooves include a first groove 14 and a second groove 15. The first groove 14 is located on the upper rear side of the cutter head 1, and the fixing block on its front side is the first fixing block 16 of the cutter head 1. The rear side of the first fixing block 16 corresponding to the first groove 14 is its mounting surface, which is the first mounting surface 18. The second groove 15 is located on the lower front side of the cutter head 1, and the fixing block on its rear side is the second fixing block 17 of the cutter head 1. The front side of the second fixing block 17 corresponding to the second groove 15 is its mounting surface, which is the second mounting surface 19. Both the first mounting surface 18 and the second mounting surface 19 are provided with multiple mounting slots corresponding to each cutting step. Each mounting slot is provided with a corresponding blade. The blade can be detachably and fixedly installed in the mounting slot. The cutting edge of each blade is located at the connection between the mounting surface and the step surface of the corresponding cutting step, which is the cutting edge of the cutter head 1 for cutting the shaft head 4.

[0026] Furthermore, the upper surface of the second fixing block 17 corresponding to the first cutting step 11 is an inclined plane that gradually slopes downwards along the first mounting surface 18 from the tail to its top, and the top of the inclined plane is lower than the axis of the cutting head 1. The mounting groove includes a first groove and a third groove on the first mounting surface 18, and a second groove, a fourth groove, and a fifth groove on the second mounting surface 19. The first groove is located at the lower end of the top side of the first mounting surface 18, and the blade installed in it is a top core cutter 53. The lower end of the cutting edge of the top core cutter 53 is lower than the axis of the cutting head 1. The second groove is located at the top of the second mounting surface 19, and the blade installed in it is a top peripheral cutter 54. The distance from the upper end of the cutting edge of the top peripheral cutter 54 to the axis of the cutting head 1 is not greater than the distance from the upper end of the cutting edge of the top core cutter 53 to the axis of the cutting head 1. The bottom of the cutting edge of the top peripheral cutter 54... The end is lower than the sidewall of the corresponding first cutting step 11, and its distance to the axis of the cutting head 1 corresponds to the radius of the inner hole 41 of the stepped hole. Thus, the cutting edges of the top peripheral cutter 54 and the top peripheral cutter 54 correspond to the inner and outer rings of the inner hole 41, respectively, and the two form a complete top cutting edge 5. When cutting the shaft head 4, the top core cutter 53 and the top peripheral cutter 54 cooperate to form a full-coverage cut on the section of the shaft head 4 corresponding to the inner hole 41, thereby machining a complete inner hole 41. The third groove is set on the first mounting surface 18 corresponding to the second cutting step 12, and the insert installed in it is the first cutting edge 55. The fourth groove is set on the second mounting surface 19 corresponding to the second cutting step 12, and the insert installed in it is the second cutting edge 56. The cutting edges of the first cutting edge 55 and the second cutting edge 56 are both middle cutting edges 51, and the radial dimension of their cutting edges is... All correspond to the difference in radial dimensions between the outer hole 42 and the inner hole 41. Specifically, the distance from the outer end of the cutting edge of the first cutting tool 55 and the second cutting tool 56 to the axis of the cutting head 1 is greater than the radial dimension of the outer hole 42 of the stepped hole, and the distance from the inner end of the cutting edge of both to the axis of the cutting head 1 is less than the distance from the bottom end of the cutting edge of the top peripheral cutting tool 54 to the axis of the cutting head 1. During operation, the first cutting tool 55 and the second cutting tool 56 cooperate to form a covering cut on the section of the shaft head 4 corresponding to the outer hole 42, thereby machining the complete outer hole 42. The fifth groove is set on the second mounting surface 19 corresponding to the third cutting step 13, and the insert installed in it is the tail cutting tool 57. The cutting edge of the tail cutting tool 57 is the tail cutting edge 52. The radial dimension of the tail cutting edge 52 corresponds to the difference between the maximum inner diameter of the chamfered hole 43 and the inner diameter of the outer hole 42. The distance from the bottom end to the axis of the cutter head 1 is greater than the radial dimension of the chamfered hole 43, and the distance from its top end to the axis of the cutter head 1 is less than the distance from the outer end of the middle cutting edge 51 to the axis of the cutter head 1. During operation, the tail cutter 57 forms a covering cut on the cross section of the shaft head 4 corresponding to the chamfered hole 43, thereby machining a complete chamfered hole 43. This setting makes it easier for the tool to continuously cut the stepped hole, preventing the appearance of broken cutting layers. Furthermore, the setting of two inserts each for the top cutting edge 5 and the middle cutting edge 51 makes cutting the shaft head 4 easier, more convenient, and faster, reducing the need for frequent replacement due to rapid insert wear. Moreover, the axial projection distance from the cutting edge of the top core cutter 53 and the top peripheral cutter 54 to the cutting edge of the first middle cutter 55 and the second middle cutter 56 is the same as the depth difference from the inner hole 41 and the outer hole 42 to the tail face of the shaft head 4.The axial projection distance from the cutting edges of the first and second cutting edges 55 to the cutting edge of the last cutting edge 57 is the same as the depth difference between the outer hole 42 and the chamfered hole 43 to the tail face of the shaft head 4. This setting ensures the accuracy of the one-time forming of the stepped hole.

[0027] Furthermore, the inner end of the outer hole 42 is provided with a transition step 44, which is coaxial with the outer hole 42. Its outer end is connected to the inner end of the outer hole 42, and its inner end is connected to the outer end of the inner hole 41. The transition step 44 is a trumpet shape with its sidewall gradually moving away from the axis of the shaft head 4 from the inside to the outside. Its sidewall is at a 60° angle with the axis. The middle cutting edge 51 on the second cutting edge 12 corresponding to the outer hole 42 is set as an inclined shape corresponding to the transition step 44, gradually moving away from the axis of the cutting head 1 from its top to its tail. The cutting edges of the first cutting edge 55 and the second cutting edge 56 are both set with an angle of 60° with the axis of the cutting head 1. The sidewall of the chamfered hole 43 is at a 45° angle with its axis, and the tail cutting edge 52 is corresponding to it. The cutting edge of the tail cutting edge 57 is set as an inclined shape with an angle of 45° gradually moving away from the axis of the cutting head 1 from its top to its tail. This setting makes it easier for the tool to form the stepped hole in one operation.

[0028] During operation, firstly, using the outer ring of the spindle head 4 for positioning, the spindle head 4 and the cutting tool are fixedly installed on the corresponding coaxial sides of the drilling machine worktable. Then, the drilling machine is started, the spindle head 4 remains stationary, and the cutting tool begins to rotate and move towards the drill bit under the drive of the drilling machine. Next, the top cutting edge 5 of the cutting tool first contacts the tail face of the spindle head 4 and cuts it. As the cutting tool continues to move towards the spindle head 4, its machining of the spindle head 4 also deepens. When it penetrates to the point where the middle cutting edge 51 contacts the tail face of the spindle head 4, the middle cutting edge 51 begins to cut the spindle head 4 with the rotation of the cutting head 1. Further, when the cutting tool penetrates the spindle head 4 to the point where the tail cutting edge 52 contacts the tail face of the spindle head 4, the tail cutting edge 52 begins to cut the spindle head 4 with the rotation of the cutting head 1 until the outer end of the tail cutting edge 52 contacts the tail face of the spindle head 4 and stops. At this time, the cutting tool is controlled to move away from the spindle head 4 and return to its initial position on the drilling machine worktable and stops. At this time, the one-time machining of the stepped hole at the tail of the spindle head 4 is completed.

[0029] This utility model's cutting tool for machining the tail end of a shaft uses a multi-stage tool to drill and form the stepped hole at the tail end of the shaft head 4 in a single operation. Compared with traditional machining methods, this tool is simpler and more convenient to use, with fewer steps. It reduces positioning errors that may result from multiple tool changes and minimizes the possibility of diameter deviations and surface roughness that may occur when machining small-diameter holes in depth using tools with a large length-to-diameter ratio alone. This improves the accuracy and quality of machining the stepped hole in the shaft head 4, while also increasing the machining speed, yield, and wear rate. Overall, it reduces the difficulty and cost of machining the shaft head 4.

[0030] It is understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by this utility model.

Claims

1. A cutting tool for machining the head and tail of a shaft, characterized in that, It includes a cylindrical blade (2), a coaxial corresponding handle (3) at the tail end of the blade (2), and a coaxial corresponding blade head (1) at the top end of the blade (2). The blade (2), blade head (1) and handle (3) are integrally formed. The front side wall of the handle (3) is provided with a side plane parallel to its axis and extending to the tail end of the handle (3). The top end of the blade head (1) is provided with multiple blade steps corresponding to the stepped hole at the tail end of the shaft head (4). Each blade step is provided with a corresponding cutting edge.

2. The cutting tool for machining the head and tail of a shaft according to claim 1, characterized in that, The stepped hole at the tail of the shaft head (4) includes three coaxial holes: an inner hole (41), an outer hole (42), and a chamfered hole (43). The cutting edge on the cutting head (1) includes a first cutting edge (11), a second cutting edge (12), and a third cutting edge (13) arranged sequentially from the top of the cutting head (1) to its tail and corresponding to each other on the same axis. The three cutting edges correspond to the inner hole (41), the outer hole (42), and the chamfered hole (43) of the stepped hole in sequence. The cutting edge corresponding to each cutting edge is located on its top surface. The radial dimension radiated by the cutting edge on each cutting edge is greater than the radial dimension of its step surface and is equal to the radial step surface dimension of the corresponding hole step.

3. The cutting tool for machining the head and tail of a shaft according to claim 2, characterized in that, The cutting edge includes a top cutting edge (5) on the top surface of the first cutting step (11), a middle cutting edge (51) on the top surface of the second cutting step (12), and a tail cutting edge (52) on the top surface of the third cutting step (13). The side wall of the cutting head (1) has two corresponding inner grooves on opposite sides. The top of the inner groove extends to the top surface of the cutting head (1), and the tail end extends to the middle of the third cutting step (13). The two inner grooves radially divide the corresponding end of the cutting head (1) into two opposite fixed blocks along the circumferential direction. The two fixed blocks are connected at the axis of the cutting head (1). Each fixed block has at least one side as a mounting surface. The cutting edge is located at the connection between the mounting surface and the top surface of the corresponding cutting step, and it extends along the axis to the top side of the corresponding cutting step surface.

4. The cutting tool for machining the head and tail of a shaft according to claim 3, characterized in that, The inner groove includes a first groove (14) located on the rear side of the upper end of the cutter head (1) and a second groove (15) located on the front side of the lower end of the cutter head (1). The fixing block in front of the first groove (14) is the first fixing block (16), and the surface on the first fixing block (16) corresponding to the first groove (14) is its mounting surface, which is the first mounting surface (18). The fixing block behind the second groove (15) is the second fixing block (17), and the surface on the second fixing block (17) corresponding to the second groove (15) is its mounting surface, which is the second mounting surface (19). Both the first mounting surface (18) and the second mounting surface (19) are provided with multiple mounting slots corresponding to each cutter step. Each mounting slot is provided with a detachable and fixedly mounted blade. The cutting edge of the blade is located at the connection between the mounting surface and the step surface of the corresponding cutter step, which is the cutting edge of the cutter head (1).

5. The cutting tool for machining the head and tail of a shaft according to claim 4, characterized in that, The upper surface of the second fixing block (17) corresponding to the first cutting step (11) is an inclined surface that gradually slopes downward from the tail to the top along the first mounting surface (18), with the top end lower than the axis of the cutting head (1). The mounting groove includes a first groove, a second groove, a third groove, a fourth groove, and a fifth groove. The first groove is located at the lower end of the top side of the first mounting surface (18), and a core cutting tool (53) is installed inside it. The second groove is located at the top of the second mounting surface (19), and a peripheral cutting tool (54) is installed inside it. The cutting edges of the peripheral cutting tool (54) and the peripheral cutting tool (54) are... The mouth forms a complete top edge (5). The third groove is located on the first mounting surface (18) corresponding to the second cutting step (12), and the blade installed in it is the middle blade (55). The fourth groove is located on the second mounting surface (19) corresponding to the second cutting step (12), and the blade installed in it is the middle blade (56). The cutting edges of the middle blade (55) and the middle blade (56) are both middle edges (51). The fifth groove is located on the second mounting surface (19) corresponding to the third cutting step (13), and the blade installed in it is the tail blade (57). The cutting edge of the tail blade (57) is the tail edge (52).

6. The cutting tool for machining the head and tail of a shaft according to claim 3, characterized in that, The inner end of the outer hole (42) is provided with a coaxial transition step (44). The two ends of the transition step (44) are respectively connected to the inner end of the outer hole (42) and the outer end of the inner hole (41). Its sidewall is a trumpet shape that gradually moves away from the axis at a 60° angle from the inside to the outside. The middle cutting edge (51) corresponding to the outer hole (42) is set as an inclined shape corresponding to the transition step (44), which gradually moves away from the axis of the cutting head (1) at a 60° angle from its top end to its tail end.

7. The cutting tool for machining the head and tail of a shaft according to claim 3, characterized in that, The chamfered hole (43) has a sidewall at an angle of 45° to its axis, and the corresponding tail cutting edge (52) is set to be inclined at 45° from the top to the tail, gradually moving away from the axis of the cutting head (1).

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