High-reliability rear end support spindle

Abstract

The application relates to a high-reliability rear-end support main shaft, which comprises a main shaft body, a sleeve and a support bearing, the main shaft body extends to the rear end along the axial direction and forms a cantilever shaft, a support seat is sleeved on the cantilever shaft, and a cylindrical roller bearing is arranged between the support seat and the cantilever shaft; a first fixing member is arranged at the position of the cantilever shaft close to the cylindrical roller bearing, a coding wheel is arranged on the first fixing member, a second fixing member is arranged on the support seat, and an encoder reading head is arranged on the second fixing member; the cylindrical roller bearing is configured to limit the radial displacement of the cantilever shaft and allow the axial sliding of the main shaft body relative to the support seat when the main shaft body is heated and expanded; the radial runout of the rear end of the main shaft is effectively inhibited, the detection precision and control precision are improved, the axial displacement caused by thermal expansion is effectively compensated, the abnormal change or jamming of the bearing pre-tightening force and other faults are avoided, and the operation reliability and service life of the main shaft are improved.

Description

Technical Field

[0001] This invention relates to the field of machining equipment technology, and in particular to a highly reliable rear-end support spindle for CNC machine tools. Background Technology

[0002] Traditional machine tool spindles (such as those used in gantry machining) operate under high-speed, high-load conditions (roughing, large cutting volume). The total length of the spindle section is about 1 meter. Currently, mainstream spindle structures typically only have rigid support at the front bearing assembly, while the rear section used to mount the encoder is relatively long and lacks effective radial constraint, often being suspended or having only a small clearance fit. This causes vibration at the rear end of the spindle during machining, resulting in unstable signal reception by the rear encoder reader and frequent alarm signals from the machine tool system. Because the mounting distance between the rotating encoder wheel and the non-rotating encoder is only 0.15 mm, the vibration and runout amplitude at the rear end of the spindle is large, easily damaging the encoder reader. Since the vibration can be transmitted to the front end, it also leads to decreased machining accuracy, shortened tool life, and increased noise.

[0003] Meanwhile, the spindle will undergo thermal expansion during long-term operation, causing the spindle body to elongate axially. If this axial degree of freedom is restricted, it will cause unexpected changes in the bearing preload, or even lead to serious failures such as bearing seizure. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a highly reliable rear-end support spindle, which solves the problem of insufficient radial support stiffness of the existing spindle rear-end cantilever structure and can compensate for axial displacement caused by spindle thermal expansion.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: a high-reliability rear-end support spindle, including a spindle body, a sleeve sleeved on the spindle body, and a support bearing located between the spindle body and the sleeve. The sleeve is fixed to the machine tool housing. The spindle body extends axially to the rear end to form a cantilever shaft. A support seat is sleeved on the cantilever shaft. A cylindrical roller bearing is provided between the support seat and the cantilever shaft. The outer side of the support seat is fixed to the machine tool housing. A first fixing member is provided on the cantilever shaft near the cylindrical roller bearing. An encoder wheel is provided on the first fixing member. A second fixing member is provided on the support seat. An encoder read head is provided on the second fixing member. The encoder read head cooperates with the encoder wheel.

[0006] The cylindrical roller bearing is configured to limit the radial displacement of the cantilever shaft and allow the spindle body to slide axially relative to the support when thermally expanded, thereby providing axial freedom.

[0007] More specifically, the end face of the support base away from the sleeve at its center position is recessed to form a first stepped hole, and a second stepped hole is provided in the first stepped hole, and the cylindrical roller bearing is disposed in the first stepped hole.

[0008] More specifically, a retaining ring is fixed on the end face of the support base. The outer diameter of the retaining ring is larger than the outer diameter of the first stepped hole, and the inner diameter of the retaining ring is smaller than the outer diameter of the first stepped hole. The retaining ring extends from the position near the inner ring toward the cylindrical roller bearing to form a retaining ring abutment, which abuts against the end face of the outer ring of the cylindrical roller bearing.

[0009] More specifically, the main spindle body includes a pull rod assembly and a mandrel sleeved on the outside of the pull rod assembly. A cutter pin hole is provided at the rear center of the mandrel. The cutter pin hole extends through the radial direction of the mandrel. A cutter pin is provided in the cutter pin hole. The cutter pin is fixedly connected to the pull rod assembly. The cutter pin moves the pull rod assembly in the axial direction.

[0010] More specifically, a cutting cylinder is provided on the end face of the support base near the sleeve; one end of the cutting cylinder is fixed on the support base and the other end is fixed on the sleeve. A piston is provided inside the cutting cylinder and is fixed on the cutting pin. The reciprocating motion of the piston drives the cutting pin to reciprocate.

[0011] More specifically, the cylindrical surface of the support base away from the cantilever shaft protrudes outward in the radial direction and is clearance-fitted with the machine tool housing.

[0012] More specifically, the first fixing member is annularly sleeved on the cantilever shaft, and a third stepped hole is formed inwardly on the end face of the first fixing member away from the sleeve at the center position. A fixing nut is provided in the third stepped hole, and an external thread that mates with the fixing nut is provided on the cantilever shaft; the fixing nut presses the first fixing member against the end face of the inner ring of the cylindrical roller bearing.

[0013] More specifically, the end face of the first fixing member near the cylindrical roller bearing extends towards the cylindrical roller bearing to form an inner ring abutment plate, which abuts against the end face of the inner ring of the cylindrical roller bearing.

[0014] More specifically, an installation step is provided on the cantilever shaft, and the inner ring of the cylindrical roller bearing is disposed within the installation step, with the end face of the inner ring near the sleeve abutting against the step of the installation step.

[0015] More specifically, the outer ring of the end face of the first fixing member away from the sleeve is provided with a stepped groove for fixing the coding wheel.

[0016] The beneficial effects of this invention are as follows: by setting a support seat and cylindrical roller bearings on the cantilever shaft, reliable radial support is provided for the rear cantilever structure, effectively suppressing the radial runout of the rear end of the spindle during high-speed rotation, improving the detection accuracy of the encoder and the overall control accuracy of the machine tool; the structure of the cylindrical roller bearings allows the spindle body to slide axially relative to the support seat when it is thermally expanded, effectively compensating for the axial displacement caused by thermal expansion, avoiding abnormal changes in bearing preload or jamming, and improving the operating reliability and service life of the spindle. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the high-reliability back-end support spindle structure of the present invention; Figure 2 yes Figure 1 Enlarged structural diagram of part A in the middle; Figure 3 yes Figure 1 Enlarged structural diagram of part B in the middle; Figure 4 This is a schematic diagram of the mandrel structure of the present invention; Figure 5 This is a schematic diagram of the structure of the first fixing member of the present invention; Figure 6 This is a schematic diagram of the retaining ring of the present invention.

[0018] In the diagram: 10. Spindle body; 11. Tie rod assembly; 1111. First tie rod; 1112. Tool holder; 1113. Tie rod connector; 11131. Connecting hole; 1114. Return disc spring; 1121. Second tie rod; 1122. Tie rod positioning component; 11221. Center hole; 12. Mandrel; 121. First part; 122. Second part; 1221. Mounting step; 123. Tool break pin hole; 13. Cantilever shaft; 14. Tool break pin; 20. Sleeve; 21. Mounting flange; 30. Support bearing; 40. Support base; 41. First step hole; 42. Second step hole; 50. Cylindrical roller bearing; 60. Connecting flange; 70. First fixing component; 71. Inner ring abutment; 72. Second sealing groove; 73. Second bearing seal ring; 74. Step groove; 75. Third step hole; 80. Second fixing part; 90. Retaining ring; 91. Retaining ring abutment; 92. First sealing groove; 93. First bearing seal ring; 100. Encoding wheel; 200. Encoder reader head; 300. Fixing nut; 400. Cutting cylinder; 410. Piston. Detailed Implementation

[0019] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The direction of movement is also relative and is not limited to an absolute direction of movement. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] like Figures 1-6 This application provides a high-reliability rear-end support spindle to solve the problems of thermal expansion compensation, insufficient rear-end rigidity, and low encoder protection level in high-speed spindle systems. The high-reliability rear-end support spindle includes a spindle body 10, a sleeve 20 sleeved on the spindle body 10, and a support bearing 30 located between the spindle body 10 and the sleeve 20. The sleeve 20 is fixed to the machine tool housing. The spindle body 10 extends axially to the rear end to form a cantilever shaft 13. A support seat 40 is sleeved on the cantilever shaft 13. A cylindrical roller bearing 50 is provided between the support seat 40 and the cantilever shaft 13. The outer side of the support seat 40 is also fixed to the machine tool housing, thereby forming a high-rigidity support structure with both the front and rear ends fixed, effectively suppressing vibration at the end of the spindle.

[0023] The spindle body 10 is divided into a front end, a middle end, and a rear end along the axial direction. The front end of the spindle body 10 is used to install the cutting tool, and the rear end is a cantilever shaft 13 structure. The spindle body 10 is driven by the main transmission system of the machine tool and achieves high-speed rotation under the support of the support bearing 30. The sleeve 20 is cylindrically sleeved on the outside of the spindle body 10, and the support bearing 30 is installed on the inside of the sleeve 20. The support bearing 30 connects the sleeve 20 and the spindle body 10 and allows relative rotation between the two. The sleeve 20 is provided with a mounting flange 21, which is fixedly connected to the machine tool housing by a locating pin and bolts, so that the sleeve 20, the spindle body 10, and its internal components are stably installed in the machine tool housing, ensuring the integrity of the spindle unit.

[0024] The support bearing 30 is provided in two sets according to its installation position and functional requirements. The first set is set near the front end of the spindle body 10 to bear radial and axial forces, and the second set is set in the middle of the spindle body 10 to provide intermediate support rigidity. The inner ring of the support bearing 30 is interference-fitted with the spindle body 10, and the outer ring is clearance-fitted with the sleeve 20. Depending on the specific application scenario of the machine tool, the support bearing 30 can be an angular contact ball bearing (suitable for high-speed light load and high-precision machining) or a tapered roller bearing (suitable for low-speed heavy load and heavy cutting). The specific type is determined according to the spindle's limiting speed, rigidity requirements and load characteristics.

[0025] The main spindle body 10 adopts a split composite structure, and the main spindle body 10 includes a tie rod assembly 11 and a spindle 12 sleeved on the outside of the tie rod assembly 11; as Figure 4 A cutter pin hole 123 is provided at the rear center of the mandrel 12. The cutter pin hole 123 extends radially through the mandrel 12. A cutter pin 14 is disposed within the cutter pin hole 123. The cutter pin 14 is fixedly connected to the tie rod assembly 11. The cutter pin hole 123 is larger than the size of the cutter pin 14, allowing the cutter pin 14 to move axially within the cutter pin hole 123. Therefore, the cutter pin 14 drives the tie rod assembly 11 to move axially within the mandrel 12. The mandrel 12 can be divided into a front part 121 and a rear part 122, with the cutter pin hole 123 as the boundary. The support bearing 30 is disposed on the first part 121, and the cylindrical roller bearing 50 is disposed on the second part 122. The cantilever shaft 13 includes the second part 122 and the second tie rod assembly.

[0026] like Figure 1 and Figure 3The pull rod assembly 11 shown includes a first pull rod group and a second pull rod group. The first pull rod group is located on the side of the cutter pin 14 closer to the sleeve 20, and the second pull rod group is located on the side of the cutter pin 14 away from the sleeve 20. The first pull rod group includes a first pull rod 1111, a cutter fixing member 1112 disposed at one end of the first pull rod 1111, a pull rod connector 1113 disposed at the other end of the first pull rod 1111, and a return disc spring 1114 sleeved on the outside of the first pull rod 1111. The second pull rod group includes a second pull rod 1121 and a second pull rod 1122 disposed on the second pull rod 1111. 21 A pull rod positioning member 1122 at the end away from the cutter pin 14, the second pull rod 1121 is fixed to the middle of the cutter pin 14 by threads and protrudes from the cutter pin 14, the pull rod connector 1113 is provided with a connecting hole 11131 in the middle, and the part of the second pull rod 1121 protruding from the cutter pin 14 is inserted into the connecting hole 11131; a central hole 11221 is provided at the end of the pull rod positioning member 1122 near the cutter pin 14, and the end of the second pull rod 1121 can be inserted into the central hole 11221 and can move axially within the central hole 11221.

[0027] A tool-changing cylinder 400 is provided on the end face of the support base 40 near the sleeve 20; one end of the tool-changing cylinder 400 is fixed to the support base 40 by bolts, and the other end is fixed to the sleeve 20; a piston 410 is provided inside the tool-changing cylinder 400, and the piston 410 can reciprocate along the axial direction. The piston 410 abuts against the tool-changing pin 14. The tool-changing cylinder 400 pushes the pull rod assembly 11 to reciprocate through the cooperation of the piston 410 and the return disc spring 1114 to realize the tool changing operation.

[0028] like Figure 2 A first fixing member 70 is provided near the cylindrical roller bearing 50 on the cantilever shaft 13 shown. The first fixing member 70 is ring-shaped and sleeved on the cantilever shaft 13. An encoder wheel 100 is fastened to the first fixing member 70 by screws. A second fixing member 80 is fixed on the support base 40. A high-resolution encoder read head 200 is installed on the second fixing member 80. The encoder read head 200 maintains a small air gap with the encoder wheel 100 and is used for non-contact detection of the real-time rotation angle and position information of the spindle, providing closed-loop feedback for the spindle servo control system.

[0029] The cylindrical roller bearing 50 is configured as a radially rigid support with axial free extension to limit the radial displacement of the cantilever shaft 13, while allowing the main shaft body 10 to slide axially relative to the support seat 40 when it expands due to heat. Since the rollers and raceways of the cylindrical roller bearing 50 are in line contact, it has a large radial load capacity and high rigidity, but cannot withstand large axial forces. Therefore, it can provide reliable radial support for the cantilever end to prevent the rear end of the main shaft from sagging, and can also provide free axial movement space for the thermal expansion of the main shaft, avoiding abnormal changes in bearing preload or jamming.

[0030] The support base 40 has a first stepped hole 41 formed inward at the end away from the sleeve 20, which is used to accommodate the outer ring of the bearing. A second stepped hole 42 is provided in the first stepped hole 41. The diameter of the second stepped hole 42 is smaller than the diameter of the first stepped hole 41, thereby forming a positioning step in the axial direction. The cylindrical roller bearing 50 is disposed in the first stepped hole 41, and the outer ring of the cylindrical roller bearing 50 is fitted with the inner wall of the first stepped hole 41. The second stepped hole 42 and the cantilever shaft 13 form an annular receiving space. This space can not only be used to store grease, but also serve as a deposition area for centrifugal dust and debris, preventing impurities from directly entering the bearing raceway.

[0031] Furthermore, to limit the axial movement of the cylindrical roller bearing 50, such as Figure 6 A retaining ring 90 is fixed to the end face of the support base 40. The retaining ring 90 is used to cover the first stepped hole 41. The outer diameter of the retaining ring 90 is larger than the outer diameter of the first stepped hole 41. Here, countersunk screws are used to fix the retaining ring 90 to the support base 40. The inner diameter of the retaining ring 90 is smaller than the outer diameter of the first stepped hole 41. That is, the inner ring of the retaining ring 90 partially blocks the first stepped hole 41, thereby preventing the outer ring of the bearing from coming out. Furthermore, the position of the retaining ring 90 near the inner ring extends vertically towards the cylindrical roller bearing 50 to form a retaining ring abutment 91. The retaining ring abutment 91 abuts against the end face of the outer ring of the cylindrical roller bearing 50, and is used to axially position and limit the outer ring of the cylindrical roller bearing 50.

[0032] To improve sealing performance, the retaining ring abutment 91 extends into the first stepped hole 41, and a first bearing seal ring 93 is provided between the retaining ring abutment 91 and the inner wall of the first stepped hole 41. Furthermore, a first sealing groove 92 is formed on the side of the retaining ring abutment 91 near the support seat 40, and the first bearing seal ring 93 is disposed within the first sealing groove 92 and compressed and deformed to fit tightly against the inner wall of the sleeve 20. The first bearing seal ring 93 is used to prevent external high-pressure coolant, iron filings, and other contaminants from entering the working area of ​​the cylindrical roller bearing 50, while also preventing internal grease leakage.

[0033] A first fixing member 70 is provided on the cantilever shaft 13 near the cylindrical roller bearing 50. The first fixing member 70 is annularly sleeved on the cantilever shaft 13. An encoder wheel 100 is provided on the first fixing member 70. A second fixing member 80 is provided on the support base 40. An encoder reading head 200 is provided on the second fixing member 80. The encoder reading head 200 cooperates with the encoder wheel 100 to acquire the spindle motion information. This layout places the encoder at the end of the spindle, away from the cutting heat source, which improves the thermal stability of the feedback system.

[0034] like Figure 5 As shown, a third stepped hole 75 is formed inwardly on the end face of the first fixing member 70 away from the sleeve 20 at the center position. A fixing nut 300 is provided in the third stepped hole 75. An external thread that mates with the fixing nut 300 is provided on the cantilever shaft 13. By tightening the fixing nut 300, the first fixing member 70 can be tightly pressed against the end face of the inner ring of the cylindrical roller bearing 50, thereby achieving axial fixation of the first fixing member 70 and the inner ring of the cylindrical roller bearing 50, ensuring that there is no loosening or displacement between it and the second spindle 132 under high-speed rotation.

[0035] Further preferably, to ensure coaxiality, the end face of the first fixing member 70 near the cylindrical roller bearing 50 extends towards the cylindrical roller bearing 50 to form an inner ring abutment plate 71. The inner ring abutment plate 71 abuts against the end face of the inner ring of the cylindrical roller bearing 50, axially positioning the inner ring of the cylindrical roller bearing 50 and ensuring the relative position of the inner ring of the cylindrical roller bearing 50 and the shaft is stable. A second bearing seal ring 73 is provided between the inner ring abutment plate 71 and the inner ring of the cylindrical roller bearing 50. Further, a second sealing groove 72 is provided at the corresponding position of the inner ring abutment plate 71. The second bearing seal ring 73 is disposed in the first sealing groove 92 and is compressed and deformed, closely adhering to the end face of the inner ring of the cylindrical roller bearing 50. The function of the second bearing seal ring 73 is the same as the function of the first bearing seal ring 93.

[0036] The outer ring of the first fixing member 70 away from the end face of the sleeve 20 is provided with a stepped groove 74. The encoder wheel 100 is radially positioned and fixedly installed on the first fixing member 70 through the stepped groove 74, realizing a rigid connection between the encoder wheel 100 and the main shaft body 10. This facilitates quick positioning and fixing of the encoder, improves assembly efficiency, and allows for quick disassembly and replacement during maintenance, reducing maintenance costs.

[0037] An installation step 1221 is provided on the cantilever shaft 13. The inner ring of the cylindrical roller bearing 50 is disposed in the installation step 1221 and is interference-fitted with the spindle 12. The end face near the sleeve 20 abuts against the step of the installation step 1221. The installation step 1221 cooperates with the first fixing member 70, the fixing nut 300, and the inner ring abutment plate 71 to axially position and clamp the inner ring of the cylindrical roller bearing 50 from both sides, forming a rigid rotating whole, ensuring that the inner ring of the cylindrical roller bearing 50 remains stable and free from relative slippage during high-speed rotation.

[0038] To further enhance the stability of the rear support, the cylindrical surface of the support seat 40 away from the cantilever shaft 13 protrudes outward in the radial direction to form a protrusion. This protrusion is clearance-fitted with the machine tool housing, which can reserve a small amount of deformation space for the thermal expansion of the spindle to avoid thermal jamming, and can also buffer high-frequency vibration and reduce the difficulty of assembly alignment.

[0039] This application provides reliable radial support for the rear cantilever structure by setting a support seat 40 and a cylindrical roller bearing 50 on the cantilever shaft 13, effectively suppressing the radial runout of the rear end of the spindle during high-speed rotation, and improving the detection accuracy of the encoder and the overall control accuracy of the machine tool. The structure of the cylindrical roller bearing 50 allows the spindle body 10 to slide axially relative to the support seat 40 when it is thermally expanded, effectively compensating for the axial displacement caused by thermal expansion and avoiding abnormal changes in bearing preload or jamming. In conjunction with the tool-changing hydraulic cylinder 400 integrated between the support seat 40 and the sleeve 20 for driving tool changing, and the sealing structure composed of a retaining ring 90 and a double bearing seal ring, the overall rigidity, assembly maintainability, and dustproof and waterproof performance of the rear end are further enhanced, significantly improving the reliability and service life of the spindle operation.

[0040] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A high-reliability rear-end support spindle, comprising a spindle body (10), a sleeve (20) sleeved on the spindle body (10), and a support bearing (30) located between the spindle body (10) and the sleeve (20), wherein the sleeve (20) is fixed to a machine tool housing, and the spindle body (10) extends axially toward the rear end to form a cantilever shaft (13), characterized in that, A support seat (40) is sleeved on the cantilever shaft (13), and a cylindrical roller bearing (50) is provided between the support seat (40) and the cantilever shaft (13). The outer side of the support seat (40) is fixed to the machine tool housing. A first fixing member (70) is provided on the cantilever shaft (13) near the cylindrical roller bearing (50). An encoder wheel (100) is provided on the first fixing member (70). A second fixing member (80) is provided on the support seat (40). An encoder reading head (200) is provided on the second fixing member (80). The encoder reading head (200) cooperates with the encoder wheel (100). The cylindrical roller bearing (50) is configured to limit the radial displacement of the cantilever shaft (13) and allow the spindle body (10) to slide axially relative to the support (40) when thermally expanded, in order to provide axial freedom.

2. The high-reliability rear-end support spindle according to claim 1, characterized in that, The end face of the support base (40) away from the sleeve (20) is recessed to form a first stepped hole (41), and a second stepped hole (42) is provided in the first stepped hole (41). The cylindrical roller bearing (50) is provided in the first stepped hole (41).

3. The high-reliability rear-end support spindle according to claim 2, characterized in that, A retaining ring (90) is fixed on the end face of the support (40). The outer diameter of the retaining ring (90) is larger than the outer diameter of the first stepped hole (41), and the inner diameter of the retaining ring (90) is smaller than the outer diameter of the first stepped hole (41). The retaining ring (90) extends from the position near the inner ring toward the cylindrical roller bearing (50) to form a retaining ring abutment (91). The retaining ring abutment (91) abuts against the end face of the outer ring of the cylindrical roller bearing (50).

4. The high-reliability rear-end support spindle according to claim 3, characterized in that, The main body of the spindle includes a tie rod assembly (11) and a spindle (12) sleeved on the outside of the tie rod assembly (11). A cutter pin hole (123) is provided at the rear of the middle part of the spindle (12). The cutter pin hole (123) passes through the spindle (12) in the radial direction. A cutter pin (14) is provided in the cutter pin hole (123). The cutter pin (14) is fixedly connected to the tie rod assembly (11). The cutter pin (14) moves the tie rod assembly (11) in the axial direction.

5. The high-reliability rear-end support spindle according to claim 3, characterized in that, A cutting cylinder (400) is provided on the end face of the support base (40) near the sleeve (20); one end of the cutting cylinder (400) is fixed on the support base (40) and the other end is fixed on the sleeve (20). A piston (410) is provided inside the cutting cylinder (400). The piston (410) abuts against the cutting pin (14). The piston (410) reciprocates and pushes the cutting pin (14) to reciprocate.

6. The high-reliability rear-end support spindle according to claim 5, characterized in that, The portion of the cylindrical surface of the support base (40) away from the cantilever shaft (13) protrudes outward in the radial direction and is clearance-fitted with the machine tool housing.

7. The high-reliability rear-end support spindle according to claim 1, characterized in that, The first fixing member (70) is annularly sleeved on the cantilever shaft (13). A third step hole (75) is formed inward on the end face of the first fixing member (70) away from the sleeve (20) at the center position. A fixing nut (300) is provided in the third step hole (75). An external thread that mates with the fixing nut (300) is provided on the cantilever shaft (13). The fixing nut (300) presses the first fixing member (70) against the end face of the inner ring of the cylindrical roller bearing (50).

8. The high-reliability rear-end support spindle according to claim 7, characterized in that, The first fixing member (70) extends from the end face of the cylindrical roller bearing (50) toward the cylindrical roller bearing (50) to form an inner ring abutment (71), which abuts against the end face of the inner ring of the cylindrical roller bearing (50).

9. The high-reliability rear-end support spindle according to claim 8, characterized in that, An installation step (1221) is provided on the cantilever shaft (13), and the inner ring of the cylindrical roller bearing (50) is located inside the installation step (1221) and the end face of the inner ring near the sleeve (20) abuts against the step of the installation step (1221).

10. The high-reliability rear-end support spindle according to claim 7, characterized in that, The outer ring of the end face of the first fixing member (70) away from the sleeve (20) is provided with a stepped groove (74) for fixing the coding wheel (100).

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