Numerically controlled lathe electric spindle unit and numerically controlled lathe thereof

Abstract

This invention discloses a CNC lathe electric spindle unit and the CNC lathe thereof, belonging to the field of CNC lathe technology. It includes a spindle seat, on which a spindle body rolls via a front bearing and a rear bearing. A motor unit is disposed between the front and rear bearings of the spindle body. It also includes a cooling chamber, comprising a cylindrical seat, a semiconductor cooler, and a circulation unit. The bottom of the cylindrical seat is fixed to the top of the spindle seat. A partition is disposed on the lower inner side of the cylindrical seat. A cooling component mounting groove is integrally formed on the top surface of the cylindrical seat. A downwardly protruding tube seat is integrally formed in the middle of the cooling component mounting groove. The semiconductor cooler is fixed on the cooling component mounting groove. This invention's CNC lathe electric spindle unit and the CNC lathe can improve assembly efficiency and accuracy, suppress spindle body vibration, ensure high linearity power output, and cool both the spindle body and the stator.

Description

Technical Field

[0001] This invention specifically relates to an electric spindle unit for a CNC lathe and the CNC lathe thereof, belonging to the field of CNC lathe technology. Background Technology

[0002] CNC lathe spindles mainly include belt-driven spindles, direct-drive spindles, and electric spindles. Among them, the electric spindle is directly driven by an internal motor, thereby shortening the length of the machine tool's main drive chain to zero, realizing "zero transmission" for CNC lathes. Existing CNC lathe spindle units generally include a housing and an electric spindle. The housing has an electric spindle cavity, and the electric spindle is installed in the electric spindle cavity. Both ends of the electric spindle extend out of the housing, and the electric spindle is rotatably connected to the housing. In practical use, the electric spindle generates power loss (mechanical loss, electrical loss, etc.) during high-speed operation, which leads to heat generation. Since the electric spindle is installed inside a housing, its heat dissipation is poor, making it prone to thermal deformation and causing workpiece machining errors. To address this, Chinese Patent Publication No. CN117123811A discloses a CNC lathe electric spindle unit and the CNC lathe thereof. This electric spindle unit includes a housing, an electric spindle, a cooling mechanism, and multiple filter covers. While this structure provides uniform temperature distribution across different parts of the electric spindle and housing, during use, the heat dissipation from the housing indirectly affects the spindle, resulting in insignificant heat dissipation. High heat still exists inside the housing. Furthermore, the existing electric spindle unit suffers from cumbersome stator and housing assembly and positioning, and installation gap errors exist between the housing, stator, rotor, and spindle. This leads to rotational deviations in the power source output from the stator and rotor to the spindle, impacting machining accuracy. Summary of the Invention

[0003] To address the aforementioned issues, this invention proposes an electric spindle unit for a CNC lathe and a CNC lathe thereof, which can improve assembly efficiency and accuracy, suppress spindle vibration, ensure high linearity power output, and also provide cooling for the spindle and stator.

[0004] The CNC lathe electric spindle unit of the present invention includes a spindle seat, a spindle body rolling on the inner side of the spindle seat via a front bearing and a rear bearing, and a motor unit disposed between the front bearing and the rear bearing; it also includes a cooling chamber, the cooling chamber comprising: A cylindrical base, the bottom of which is fixed to the top of a shaft seat; a partition is provided on the lower inner side of the cylindrical base; a cooling component mounting groove is integrally formed on the top surface of the cylindrical base; and a downwardly protruding tube seat is integrally formed in the middle of the cooling component mounting groove. A semiconductor cooler is fixed on a cooling component mounting slot. The cooling end of the semiconductor cooler is embedded inside the tube seat and fits tightly against the tube seat. The heat dissipation end of the semiconductor cooler is hollow. The circulation unit includes a pump body fixed to the top surface of a partition plate and a spiral tube wound and brazed to the outer wall of a tube seat. One end of the spiral tube is connected to the output end of the pump body, and the input end of the pump body is provided with an inlet pipe. The other end of the spiral tube extends movably out of the bottom of the partition plate. A main shaft through hole is opened at the center of the bottom surface of the tube seat. A sealing unit is provided inside the main shaft through hole. An annular groove is provided on the top of the main shaft body. The annular groove and the sealing unit are rotatably installed. A heat dissipation blind hole is provided from the top of the main shaft body to above the clamping position. The output end of the spiral tube is movably embedded in the bottom of the heat dissipation blind hole, and a safety gap is provided between it and the inner wall of the heat dissipation blind hole. The motor unit includes a sandwiched outer cylinder, the inner side of which is integrated with the stator, and the sandwiched outer cylinder is limited and installed with the inner wall of the shaft seat; The bottom of the sandwich outer cylinder is connected to the upper part of the cylinder base via a flat tube; the upper part of the sandwich outer cylinder is connected to the bottom of the cylinder base.

[0005] The CNC lathe electric spindle unit of this invention uses a bearing seat as the external support system for the spindle body, and provides rigid support and rotational guidance for the spindle body through front and rear bearings. The spindle body and motor unit adopt a modular structure and are integrated as a single unit on the outside of the spindle body. After integration, the bearing seat, spindle body, and motor unit are quickly assembled into a single unit using a fitting method. A cooling chamber is fixed on the top of the bearing seat, and the cooling chamber uses a cylindrical seat as the medium-carrying unit. The cylindrical seat is divided into an upper compartment and a lower compartment by a partition. The medium in the upper compartment is directly cooled by a semiconductor cooler. The cooled medium is directly injected into the heat dissipation blind holes of the spindle body, and the heated medium in the heat dissipation blind holes is replaced in the lower compartment. The medium in the lower compartment is simultaneously pressed into the interlayer of the jacketed outer cylinder. The heated medium inside the outer cylinder is displaced to the upper compartment through a flat tube and cooled again by a semiconductor cooler. The specific working process is as follows: the semiconductor cooler cools the medium in the upper compartment, the circulation unit operates, the pump body pumps the medium in the upper compartment into the spiral tube, and the semiconductor cooler cools the tube seat and the spiral tube, thereby performing secondary cooling on the medium in the spiral tube. The cooled medium is pumped into the bottom of the heat dissipation blind hole through the spiral tube, thereby displacing the heat-absorbing medium, and discharged into the lower compartment through the top of the main shaft. After the lower compartment is filled, the medium is pressed into the jacket of the jacketed outer cylinder. Finally, the heat-absorbing medium inside the jacket is pumped into the upper compartment through the flat tube, cooled again by the semiconductor cooler, and then pumped back into the main shaft.

[0006] Furthermore, a stator is provided inside the outer cylinder of the sandwich structure, and a rotor fixed to the main shaft is provided inside the stator; the inner wall of the outer cylinder of the sandwich structure is integrally formed with a first inner protrusion that presses against the winding gap of the stator; the outer wall of the outer cylinder of the sandwich structure is integrally formed with a second inner protrusion opposite to the first inner protrusion; the top and bottom of the outer cylinder of the sandwich structure are fitted with and fixed by bolts to an upper and lower sealing seat with a convex structure; the upper and lower sealing seats are pressed against the top and bottom of the stator; magnetic bearings are provided at the top of the upper sealing seat and the bottom of the lower sealing seat; the inner wall of the shaft seat is integrally formed with a retaining rib that engages with the second inner protrusion; a limiting ring that abuts against the outer cylinder of the sandwich structure is provided at the bottom of the shaft seat; an isolation ring is pressed against the top of the motor unit; the isolation ring is fixed to the top of the retaining rib by a countersunk bolt; the rear bearing is provided at the top of the isolation ring or inside the isolation ring.

[0007] During motor unit installation, the motor unit and main shaft are assembled outside the bearing seat. During assembly, the outer cylinder and stator are positioned and installed using the first inner protrusion of the outer cylinder, achieving circumferential positioning between the outer cylinder and the stator. Next, the upper and lower sealing seats are fixed at both ends of the outer cylinder to achieve axial positioning of the stator. Then, the stator and rotor are assembled together, and magnetic bearings are assembled at both ends of the main shaft, making the motor unit and main shaft a single module that ensures linear and stable rotational force at the drive end of the main shaft. After the overall module assembly is completed, the retaining ribs on the inner wall of the bearing seat are aligned and engaged with the second inner protrusion of the outer cylinder using an alignment and embedding method, achieving circumferential positioning between the bearing seat and the outer cylinder. Axial positioning of the outer cylinder is achieved through a limiting ring and an isolation ring.

[0008] Furthermore, the outer side of the shaft seat is provided with staggered first and second brazed straight grooves; the upper and lower parts of the jacketed outer cylinder are provided with staggered threaded grooves; the bottom of the first and second brazed straight grooves is embedded with a convex guide nozzle; the guide nozzle is screwed into the threaded groove; the outer side of the cylinder seat is provided with staggered third and fourth brazed straight grooves; the top of the third and fourth brazed straight grooves is provided with a guide hole; the inner side of the first and third brazed straight grooves is brazed with a first flat tube; the second and third brazed straight grooves are provided with a first flat tube; the second and third brazed straight grooves are provided with a first flat tube; the outer side of the jacketed outer cylinder is ... second flat tube; the outer side of the jacketed outer cylinder is provided with a first flat tube; the outer side A second flat tube is brazed to the inner side of the four brazed straight grooves; both ends of the first and second flat tubes are provided with sealing plates, which together with the guide nozzles and guide holes form a closed flow channel; during installation, straight grooves are opened on the outside of the shaft seat and the cylinder seat to install the first and second flat tubes, and the two ends of the second flat tube form a flow channel through the guide nozzles and guide holes, which enables communication between the upper part of the jacketed outer cylinder and the bottom of the cylinder seat; both ends of the first flat tube form a flow channel through the guide nozzles and guide holes, which enables communication between the lower part of the jacketed outer cylinder and the upper part of the cylinder seat.

[0009] Furthermore, the bottom of the partition plate is integrally formed with multiple downwardly protruding pipe sections; the bottom surface of the pipe sections is closed; when the main shaft and stator are in a natural cooling state, the working medium enters the heat dissipation blind hole of the jacketed outer cylinder and the main shaft, and with the flow of liquid vapor, the hot steam flow enters the lower part of the partition plate of the cylinder seat; at this time, the working medium in the upper part of the partition plate is in a semiconductor cooler cooling state, and the cooling working medium cools the hot steam flow through the pipe section; it flows back to the jacket of the jacketed outer cylinder and the heat dissipation blind hole of the main shaft.

[0010] Furthermore, an umbrella-shaped guide plate is fixed to the top of the main shaft body by bolts; an overflow hole is provided in the middle of the guide plate; the guide plate can not only guide the flow of the working medium, but also achieve sealing in conjunction with the sealing unit.

[0011] Furthermore, the cylinder seat and the shaft seat are fixed by flanges or by welding; the cylinder seat is fixed to the top of the shaft seat by a detachable flange, or the shaft seat and the cylinder seat are welded together by a non-detachable welding method; when flange installation is used, the flange needs to be circumferentially slotted to ensure that the flat tube can smoothly enter the installation slots of the cylinder seat and the shaft seat.

[0012] Furthermore, the sealing unit is composed of dynamic or static seals. The sealing unit achieves the goal of maintaining a seal between the outer wall of the spindle and the cylinder seat even under working medium pressure without affecting the rotation of the spindle body.

[0013] Furthermore, a through-tube head is fixed through the center of the partition, one end of the spiral tube moves through the through-tube head, and a sealing ring is provided between the spiral tube and the through-tube head; the through-tube head can both straighten and center the end of the spiral tube that is protruding, and at the same time seal the through-tube end of the spiral tube with the partition.

[0014] A CNC lathe includes a lathe body, on which a spindle unit is mounted, the spindle unit being the CNC lathe electric spindle unit described above.

[0015] Compared with the prior art, the CNC lathe electric spindle unit and the CNC lathe of the present invention have the following advantages: 1. The spindle body and motor unit are assembled into a modular structure. During installation, the sandwiched outer cylinder, stator, rotor and spindle can be pre-integrated and installed on the outside of the shaft seat. The spindle body and motor unit can be quickly assembled by the alignment and engagement of the sandwiched outer cylinder with the inner wall of the shaft seat and the end limiting method. After assembly, the circumferential and axial limiting of the sandwiched outer cylinder can be guaranteed, which can improve the assembly efficiency and the assembly accuracy.

[0016] 2. The front and rear bearings of the electric spindle unit are ball bearings, which serve as the main support stiffness of the spindle body; and magnetic bearings are installed at both ends of the power source of the spindle body; even when the ball bearings are in a low preload state after long-term operation, they still have good dynamic performance; they can suppress spindle vibration and ensure high linearity power output.

[0017] 3. An integrated cooling system is adopted for the aligned cooling of the spindle and stator, which can quickly reduce the heat generated by the spindle and stator. When cooling the spindle and stator, passive cooling by evaporative condensation of the working medium can be achieved, or the spindle and stator can be synchronously forced cooled by the pump. The cooling of the cold medium is carried out online by a semiconductor refrigerator, which eliminates the need for external compression refrigeration heat exchange equipment, saves installation space, and facilitates the installation of the electric spindle unit. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the electric spindle unit of the CNC lathe according to the present invention.

[0019] Figure 2 This is a schematic diagram of the cooling chamber structure of the present invention.

[0020] Figure 3 This is a schematic cross-sectional view of the cooling chamber structure of the present invention.

[0021] Figure 4 This is a cross-sectional structural schematic diagram of an embodiment of the electric spindle unit for a CNC lathe according to the present invention.

[0022] Figure 5 This is a cross-sectional structural schematic diagram of another embodiment of the CNC lathe electric spindle unit of the present invention.

[0023] Figure 6 This is a schematic diagram of the axial cross-sectional structure of the motor unit of the present invention.

[0024] Figure 7 This is a schematic diagram of the axial and transverse cross-sectional structure of the motor unit of the present invention.

[0025] Figure 8 This is a schematic diagram of the flow guide nozzle structure of the present invention.

[0026] Figure 9 This is a schematic diagram of the first flat tube structure of the present invention.

[0027] Reference numerals: 1. Shaft seat, 2. Main shaft body, 3. Cylinder seat, 4. Partition plate, 5. Cooling component mounting groove, 6. Pipe seat, 7. Semiconductor cooler, 8. Pump body, 9. Spiral tube, 10. Inlet pipe, 11. Sealing unit, 12. Heat dissipation blind hole, 13. Jacketed outer cylinder, 14. Stator, 15. Rotor, 16. First inner protrusion, 17. Second inner protrusion, 18. Upper seal, 19. Lower seal, 20. Magnetic bearing, 21. Limiting ring, 22. Isolation ring, 23. First brazed straight groove, 24. Second brazed straight groove, 25. Guide nozzle, 26. Third brazed straight groove, 27. Fourth brazed straight groove, 28. Guide hole, 29. First flat tube, 30. Second flat tube, 31. Sealing plate, 32. Pipe section, 33. Guide plate, 34. Pipe end, 35. Motor unit. Detailed Implementation

[0028] Example: like Figures 1 to 9 The CNC lathe electric spindle unit shown includes a spindle seat 1, with a spindle body 2 rolling on the inner side of the spindle seat 1 via a front bearing and a rear bearing. A motor unit 35 is disposed between the front bearing and the rear bearing on the spindle body 2. It also includes a cooling chamber, which comprises: The cylindrical base 3 is fixed to the top of the shaft seat 1 at its bottom; a partition plate 4 is provided on the lower inner side of the cylindrical base 3; a cooling component mounting groove 5 is integrally formed on the top surface of the cylindrical base 3; and a downwardly protruding tube seat 6 is integrally formed in the middle of the cooling component mounting groove 5. A semiconductor cooler 7 is fixed on a cooling component mounting groove 5. The cooling end of the semiconductor cooler 7 is embedded inside the tube seat 6 and is tightly fitted to the tube seat 6. The heat dissipation end of the semiconductor cooler 7 is hollow. The circulation unit includes a pump body 8 fixed to the top surface of the partition 4 and a spiral tube 9 wound and brazed to the outer wall of the tube seat 6. One end of the spiral tube 9 is connected to the output end of the pump body 8, and the input end of the pump body 8 is provided with an inlet pipe 10. The other end of the spiral tube 9 extends movably out of the bottom of the partition 4. A main shaft through hole is opened at the center of the bottom surface of the tube seat 3. A sealing unit 11 is provided inside the main shaft through hole. An annular groove is provided on the top of the main shaft body 2. The annular groove and the sealing unit 11 are rotatably installed. A heat dissipation blind hole 12 is provided from the top of the main shaft body 2 to above the clamping position. The output end of the spiral tube 9 is movably embedded in the bottom of the heat dissipation blind hole 12, and a safety gap is provided between it and the inner wall of the heat dissipation blind hole 12. The motor unit 35 includes a sandwich outer cylinder 13, the inner side of which is integrated with the stator 14, and the sandwich outer cylinder 13 is limited and installed with the inner wall of the shaft seat 1; The bottom of the sandwich outer cylinder 13 is connected to the upper part of the cylinder base 3 through a flat tube; the upper part of the sandwich outer cylinder 13 is connected to the bottom of the cylinder base 3.

[0029] The CNC lathe electric spindle unit of this invention uses a bearing seat 1 as the external support system for the spindle body 2, and provides rigid support and rotational guidance for the spindle body 2 through front and rear bearings. The spindle body 2 and the motor unit 35 adopt a modular structure and are integrated as a single unit on the outside of the spindle body 2. After integration, the bearing seat 1, the spindle body 2 and the motor unit 35 are quickly assembled into a single unit using an alignment and fitting method. A cooling chamber is fixed on the top of the bearing seat 1. The cooling chamber uses a cylindrical seat 3 as the medium-carrying unit. The cylindrical seat 3 uses a partition 4 to form an upper compartment and a lower compartment. The medium in the upper compartment is directly cooled by a semiconductor cooler 7. The cooled medium is directly injected into the heat dissipation blind hole 12 of the spindle body 2, and the heated medium in the heat dissipation blind hole 12 is replaced in the lower compartment. The medium in the lower compartment is simultaneously pressed into the interlayer of the jacketed outer cylinder 13. The heated medium inside the jacketed outer cylinder 13 is displaced to the upper compartment through a flat tube and cooled again by the semiconductor cooler 7. The specific working process is as follows: the semiconductor cooler 7 cools the medium in the upper compartment, the circulation unit operates, the pump body 8 pumps the medium in the upper compartment into the spiral tube 9, and the semiconductor cooler 7 cools the tube seat 6 and the spiral tube 9, thereby performing secondary cooling on the medium in the spiral tube 9. The cooled medium is pumped into the bottom of the heat dissipation blind hole 12 through the spiral tube 9, thereby displacing the heat-absorbing medium, and discharged into the lower compartment through the top of the main shaft 2. After the lower compartment is filled, the medium is pressed into the jacket of the jacketed outer cylinder 13. Finally, the heat-absorbing medium inside the jacket is pumped into the upper compartment through the flat tube, cooled again by the semiconductor cooler 7, and then pumped back into the main shaft 2.

[0030] A stator 14 is disposed inside the inner side of the sandwich outer cylinder 13, and a rotor 15 fixed to the main shaft 2 is disposed inside the inner side of the stator 14; a first inner protrusion 16 is integrally formed on the inner wall of the sandwich outer cylinder 13 to press against the winding gap of the stator 14; a second inner protrusion 17 is integrally formed on the outer wall of the sandwich outer cylinder 13 opposite to the first inner protrusion 16; an upper sealing seat 18 and a lower sealing seat 19 with convex structures are embedded in and fixed to the top and bottom of the sandwich outer cylinder 13 by bolts; the upper sealing seat 18 and the lower sealing seat 19 are... The sealing seat 19 is pressed against the top and bottom of the stator 14; magnetic bearings 20 are provided at the top of the upper sealing seat 18 and the bottom of the lower sealing seat 19; the inner wall of the shaft seat 1 is integrally formed with a retaining rib that engages with the second inner protrusion 17; a limiting ring 21 that abuts against the outer cylinder 13 is provided at the bottom of the shaft seat 1; an isolation ring 22 is pressed against the top of the motor unit 35; the isolation ring 22 is fixed to the top of the retaining rib by a countersunk bolt; the rear bearing is provided at the top of the isolation ring 22 or inside the isolation ring 22.

[0031] When installing the motor unit 35, the assembly of the motor unit 35 and the main shaft 2 is completed outside the bearing seat 1. During assembly, the first inner protrusion 16 of the outer sleeve 13 is used to position and install the outer sleeve 13 and the stator 14, achieving circumferential positioning between the outer sleeve and the stator 14. Then, the upper sealing seat 18 and the lower sealing seat 19 are fixed at both ends of the outer sleeve 13 to achieve axial positioning of the stator 14. Next, the stator 14 and the rotor 15 are assembled together, and magnetic bearings 20 are assembled at both ends of the main shaft 2, so that the motor unit 35 and the main shaft 2 form an integral module, which can ensure that the drive end of the main shaft 2 maintains a linear and stable rotational force. After the overall module assembly is completed, the clamping rib on the inner wall of the bearing seat 1 is aligned and engaged with the second inner protrusion 17 of the outer sleeve 13 using the alignment and embedding method, achieving circumferential positioning between the bearing seat 1 and the outer sleeve 13. Axial positioning of the outer sleeve 13 is achieved through the limiting ring 21 and the isolation ring 22.

[0032] The shaft seat 1 has a first brazed straight groove 23 and a second brazed straight groove 24 staggered on its exterior; the upper and lower parts of the sandwich outer cylinder 13 have staggered threaded grooves; the bottom of the first brazed straight groove 23 and the second brazed straight groove 24 are embedded with convex guide nozzles 25; the guide nozzles 25 are screwed into the threaded grooves; the outer part of the cylinder seat 3 has a third brazed straight groove 26 and a fourth brazed straight groove 27 staggered on its exterior; the top of the third brazed straight groove 26 and the fourth brazed straight groove 27 has a guide hole 28; the inner sides of the first brazed straight groove 23 and the third brazed straight groove 26 are brazed with a first flat tube 29; the second brazed straight groove 24 and the fourth brazed straight groove 27 are brazed with a first flat tube 29; the second brazed straight groove 24 and the fourth brazed straight groove 27 are brazed with a first flat tube 29; the outer parts of the sandwich outer cylinder 13 have staggered threaded grooves; the outer parts of the first brazed straight groove 23 and the second brazed straight groove 24 are brazed with a first flat tube 29; the outer parts of the sandwich outer cylinder 13 have staggered threaded grooves 24 and the second flat tube 29 ... 7. A second flat tube 30 is brazed on the inner side; sealing plates 31 are provided at both ends of the first flat tube 29 and the second flat tube 30, and the sealing plates 31, the guide nozzle 25 and the guide hole 28 form a closed flow channel; during installation, straight grooves are opened on the outside of the shaft seat 1 and the cylinder seat 3 for installing the first flat tube 29 and the second flat tube 30. The two ends of the second flat tube 30 form a flow channel through the guide nozzle 25 and the guide hole 28, and the upper part of the sandwich outer cylinder 13 and the bottom of the cylinder seat 3 are connected through the flow channel; the two ends of the first flat tube 29 form a flow channel through the guide nozzle 25 and the guide hole 28, and the lower part of the sandwich outer cylinder 13 and the upper part of the cylinder seat 3 are connected through the flow channel.

[0033] The bottom of the partition 4 is integrally formed with multiple downward protruding pipe sections 32; the bottom surface of the pipe sections 32 is closed; when the main shaft 2 and stator 14 are in a natural cooling state, the working medium enters the heat dissipation blind hole 12 of the jacketed outer cylinder 13 and the main shaft 2. With the flow of liquid vapor, the hot steam flow enters the lower part of the partition 4 of the cylinder seat 3; at this time, the working medium in the upper part of the partition 4 is in a semiconductor cooler 7 cooling state, and the cooling working medium cools the hot steam flow through the pipe section 32; it flows back to the jacket of the jacketed outer cylinder 13 and the heat dissipation blind hole 12 of the main shaft 2.

[0034] The top of the main shaft 2 is fixed with an umbrella-shaped guide plate 33 by bolts; the guide plate 33 has an overflow hole in the middle; the guide plate 33 can guide the flow of the working medium, and at the same time, the guide plate 33 works with the sealing unit 11 to achieve sealing.

[0035] The cylinder seat 3 and the shaft seat 1 are fixed by flange or by welding; the cylinder seat 3 is fixed to the top of the shaft seat 1 by a detachable flange, or the shaft seat 1 and the cylinder seat 3 are welded together by a non-detachable welding method; when using flange installation, the flange needs to be circumferentially slotted to ensure that the flat tube can smoothly enter the mounting slots of the cylinder seat 3 and the shaft seat 1.

[0036] The sealing unit 11 is composed of a dynamic seal or a static seal. The sealing unit 11 can achieve the goal of not affecting the rotation of the main shaft 2, while maintaining a sealed state between the outer wall of the main shaft 2 and the cylinder seat 3 under working medium pressure.

[0037] A tube head 34 is fixed through the center of the partition plate 4. One end of the spiral tube 9 moves through the tube head 34. A sealing ring is provided between the spiral tube 9 and the tube head 34. The tube head 34 can both straighten and center the end of the spiral tube 9 that is protruding from the partition plate 4, and at the same time seal the end of the spiral tube 9 that is protruding from the partition plate 4.

[0038] A CNC lathe includes a lathe body, on which a spindle unit is mounted, the spindle unit being the CNC lathe electric spindle unit described above.

[0039] The above embodiments are merely preferred embodiments of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention are included within the scope of the present invention.

Claims

1. A CNC lathe electric spindle unit, comprising a bearing seat, a spindle body rolling on the inner side of the bearing seat via a front bearing and a rear bearing, and a motor unit disposed between the front bearing and the rear bearing; characterized in that: It also includes a cooling chamber, which comprises: A cylindrical base, the bottom of which is fixed to the top of a shaft seat; a partition is provided on the lower inner side of the cylindrical base; a cooling component mounting groove is integrally formed on the top surface of the cylindrical base; and a downwardly protruding tube seat is integrally formed in the middle of the cooling component mounting groove. A semiconductor cooler is fixed on a cooling component mounting slot. The cooling end of the semiconductor cooler is embedded inside the tube seat and fits tightly against the tube seat. The heat dissipation end of the semiconductor cooler is hollow. The circulation unit includes a pump body fixed to the top surface of a partition plate and a spiral tube wound and brazed to the outer wall of a tube seat. One end of the spiral tube is connected to the output end of the pump body, and the input end of the pump body is provided with an inlet pipe. The other end of the spiral tube extends movably out of the bottom of the partition plate. A main shaft through hole is opened at the center of the bottom surface of the tube seat. A sealing unit is provided inside the main shaft through hole. An annular groove is provided on the top of the main shaft body. The annular groove and the sealing unit are rotatably installed. A heat dissipation blind hole is provided from the top of the main shaft body to above the clamping position. The output end of the spiral tube is movably embedded in the bottom of the heat dissipation blind hole, and a safety gap is provided between it and the inner wall of the heat dissipation blind hole. The motor unit includes a sandwiched outer cylinder, the inner side of which is integrated with the stator, and the sandwiched outer cylinder is limited and installed with the inner wall of the shaft seat; The bottom of the sandwich outer cylinder is connected to the upper part of the cylinder base via a flat tube; the upper part of the sandwich outer cylinder is connected to the bottom of the cylinder base; A stator is provided inside the outer cylinder of the sandwich structure, and a rotor fixed to the main shaft is provided inside the stator. The inner wall of the outer cylinder of the sandwich structure is integrally formed with a first inner protrusion that presses against the winding gap of the stator. The outer wall of the outer cylinder of the sandwich structure is integrally formed with a second inner protrusion opposite to the first inner protrusion. The top and bottom of the outer cylinder of the sandwich structure are fitted with and fixed by bolts to an upper and lower sealing seat with a convex structure. The upper and lower sealing seats are pressed against the top and bottom of the stator. A magnetic bearing is provided at the top of the upper sealing seat and the bottom of the lower sealing seat. The inner wall of the shaft seat is integrally formed with a retaining rib that engages with the second inner protrusion. A limiting ring that abuts against the outer cylinder of the sandwich structure is provided at the bottom of the shaft seat. An isolation ring is pressed against the top of the motor unit. The isolation ring is fixed to the top of the retaining rib by a countersunk bolt. The rear bearing is located at the top of the isolation ring or inside the isolation ring.

2. The CNC lathe electric spindle unit according to claim 1, characterized in that: The shaft seat has a first brazed straight groove and a second brazed straight groove staggered on its exterior; the upper and lower parts of the jacketed outer cylinder have staggered threaded grooves; the bottom of the first and second brazed straight grooves is embedded with a convex guide nozzle; the guide nozzle is screwed into the threaded groove; the outer side of the cylinder seat has a third and a fourth brazed straight groove staggered on its exterior; the top of the third and fourth brazed straight grooves has a guide hole; a first flat tube is brazed into the inner side of the first and third brazed straight grooves; a second flat tube is brazed into the inner side of the second and fourth brazed straight grooves; sealing plates are provided at both ends of the first and second flat tubes, and the sealing plates, the guide nozzles, and the guide holes form a closed flow channel.

3. The CNC lathe electric spindle unit according to claim 1, characterized in that: The bottom of the partition is integrally formed with multiple downward protruding pipe sections; the bottom surface of the pipe sections is closed.

4. The CNC lathe electric spindle unit according to claim 1, characterized in that: An umbrella-shaped guide plate is fixed to the top of the main shaft by bolts; an overflow hole is provided in the middle of the guide plate.

5. The CNC lathe electric spindle unit according to claim 1, characterized in that: The cylinder seat and shaft seat are fixed by flanges or by welding.

6. The CNC lathe electric spindle unit according to claim 1, characterized in that: The sealing unit consists of a dynamic seal or a static seal.

7. The CNC lathe electric spindle unit according to claim 1, characterized in that: A through-tube head is fixed through the center of the partition, one end of the spiral tube moves through the through-tube head, and a sealing ring is provided between the spiral tube and the through-tube head.

8. A CNC lathe, characterized in that: The lathe includes a lathe body on which a spindle unit is mounted, the spindle unit being the CNC lathe electric spindle unit as described in claim 1.

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