A machine tool electric spindle

Abstract

The present invention relates to the technical field of machine tool electric spindles, and particularly relates to a machine tool electric spindle, which includes an installation mechanism. The installation mechanism includes a housing, one end of the housing is detachably connected with a closed cover, the other end of the housing is detachably connected with a protective cover, a motor is arranged in the housing, the output end of the motor is fixedly connected with a main shaft, a heat dissipation mechanism is arranged in the housing, the heat dissipation mechanism includes an air inlet hole opened on the housing, a heat dissipation hole is opened on the protective cover, and a heat dissipation fan is fixedly connected to one end of the main shaft close to the protective cover. Through the setting of the housing, the motor and the main shaft can be directly connected, forming a zero-transmission structure, eliminating the intermediate transmission link, improving the transmission efficiency and reducing energy loss, simplifying the structure, reducing the maintenance cost, reducing vibration and noise, and improving the running stability.

Description

Technical Field

[0001] The present invention relates to the technical field of machine tool electric spindles, and particularly to a machine tool electric spindle. Background Art

[0002] As one of the core components of a machine tool, the machine tool motor spindle undertakes the important tasks of installing workpieces or tools and realizing their rotational motion. It not only determines the speed, accuracy and efficiency in the machining process, but also directly affects the quality of the final product. With the development of industrial technology, the machine tool motor spindle has evolved from traditional mechanical drive to modern electric spindle, and its performance has been continuously improved.

[0003] The machine tool motor spindle mainly consists of a mechanical part and a drive part. The mechanical part includes components such as the spindle body and its bearings, and these components are directly related to the rigidity and stability of the spindle; while the drive part is responsible for providing power to the spindle. Traditional drive methods include belt drive, gear drive, etc. However, in recent years, due to the progress of the electric spindle technology with an in-built motor, more and more machine tools have adopted this more advanced drive method.

[0004] An electric spindle refers to a design in which the motor is integrated inside the spindle. It can achieve higher rotational speeds, more precise speed control and faster response speeds. Compared with traditional drive methods, the electric spindle reduces the energy loss and vibration problems caused by mechanical transmission, and improves the overall performance of the machine tool. In addition, the electric spindle also has the advantages of a compact structure and easy maintenance, so it is widely used in numerical control machine tools.

[0005] During the daily use of the electric spindle, it is prone to overheating problems. When the temperature is too high, it is necessary to stop the machine for heat dissipation, which affects the working efficiency of the machine tool.

[0006] Therefore, a machine tool electric spindle is needed to solve the above problems. Summary of the Invention

[0007] In order to solve the above problems, that is, to solve the problem that the machine tool electric spindle is prone to overheating during use and needs to stop for heat dissipation, the present invention provides a machine tool electric spindle.

[0008] A machine tool electric spindle includes an installation mechanism. The installation mechanism includes a housing. One end of the housing is detachably connected with a closing cover, and the other end of the housing is detachably connected with a protective cover. A motor is arranged in the housing, and the output end of the motor is fixedly connected with the spindle. A heat dissipation mechanism is arranged in the housing. The heat dissipation mechanism includes an air inlet hole opened on the housing, a heat dissipation hole is opened on the protective cover, and a heat dissipation fan is fixedly connected to one end of the spindle close to the protective cover.

[0009] Specifically, when using a machine tool, start the motor. The output end of the motor drives the main shaft to rotate, and the main shaft drives the working components on the machine tool to rotate for processing the parts. During the rotation of the main shaft, the cooling fan is driven to rotate. The cooling fan drives the gas in the housing to flow, enabling the external gas to enter the housing through the air inlet hole. Then, under the driving action of the cooling fan, the air is discharged from the heat dissipation holes, thereby taking out the heat in the housing.

[0010] Through the setting of the housing, the motor can be directly connected to the main shaft, forming a zero-transmission structure, eliminating the intermediate transmission link, improving the transmission efficiency, reducing energy loss, simplifying the structure, reducing the maintenance cost, reducing vibration and noise, and improving the running stability. Through the setting of the heat dissipation mechanism, when the main shaft rotates, the cooling fan can be driven to rotate, thereby driving the air in the housing to flow, taking out the heat, dissipating heat from the motor and the main shaft, effectively controlling the temperature of the main shaft, avoiding the influence of thermal deformation on the machining accuracy, prolonging the service life of the motor, supporting long-term continuous operation, and improving the production efficiency.

[0011] Preferably, a bearing is arranged in the housing. The bearing is a ceramic ball bearing. The bearing is located at one end of the housing close to the protective cover. The bearing is sleeved on the main shaft. The bearing is arranged on a bearing seat, and the bearing seat is fixedly connected to the inner wall of the housing.

[0012] Specifically, during use, when the main shaft rotates, the main shaft drives the bearing to rotate.

[0013] Through the setting of the bearing, the tail end of the main shaft can be supported. And through the setting of the ceramic ball bearing, the wear resistance and high temperature resistance of the bearing are improved, the friction force is reduced, and the temperature rise during the rotation of the main shaft is inhibited.

[0014] Preferably, twelve through grooves are evenly formed in the bearing seat along the circumferential direction.

[0015] Specifically, during use, when the cooling fan rotates, the gas flows in the housing through the through grooves, which is convenient for heat dissipation.

[0016] Preferably, the heat dissipation mechanism further includes a liquid cooling component arranged in the housing. The liquid cooling component includes a flow-through groove formed in the main shaft. A liquid cooling box is rotatably sleeved on the main shaft. The liquid cooling box is fixedly connected to the inner wall of the housing. Six communication grooves are evenly formed in the inner wall of the flow-through groove along the circumferential direction. The communication grooves are communicated with the liquid cooling box. The liquid cooling box is communicated with a liquid inlet pipe. The liquid inlet pipe penetrates through the housing. The liquid cooling box is communicated with a liquid outlet pipe. The liquid outlet pipe penetrates through the housing. The liquid inlet pipe and the liquid outlet pipe are communicated with a coolant circulation device.

[0017] Specifically, during use, the coolant circulation device supplies coolant into the liquid cooling box through the liquid inlet pipe. The coolant enters the circulation groove through the communication groove, flows in the circulation groove, dissipates heat from the main shaft, and dissipates heat from the motor. Then, the coolant enters the liquid outlet pipe through the liquid cooling box and then flows back into the coolant circulation device again.

[0018] Through the setting of the liquid cooling component, when the main shaft rotates at a high speed, coolant can be conveyed to the main shaft through the liquid inlet pipe, so that the coolant flows in the circulation groove, taking out the heat generated during the rotation of the main shaft and the heat generated during the operation of the motor, and cooperating with the cooling fan to dissipate heat from the main shaft and the motor, making the heat dissipation effect better.

[0019] Furthermore, the coolant circulation device is prior art and will not be elaborated here.

[0020] Preferably, a switching mechanism is provided in the housing. The switching mechanism includes a partition ring slidably connected to the inner wall of the housing. The partition ring is located on the side of the air inlet hole close to the closing cover. Six switching holes are evenly arranged in the circumferential direction on the side of the liquid cooling box close to the protection cover. A closing ring is provided on the side of the liquid cooling box close to the protection cover. The closing ring closes the switching holes. A connecting rod is fixedly connected between the closing ring and the partition ring.

[0021] Specifically, in the initial state, the closing ring closes the switching holes, and the partition ring is located on the side of the air inlet hole close to the closing cover. When the main shaft needs to rotate at a high speed, slide the connecting rod so that the connecting rod moves in the direction close to the protection cover. The connecting rod drives the partition ring to move. The partition ring closes the air inlet hole. At the same time, the connecting rod drives the closing ring to move, and the closing ring closes the switching holes. Then, the closing ring closes the through groove, and at the same time, the coolant in the liquid cooling box flows into the housing through the switching holes, directly contacting the main shaft and the motor to dissipate heat from the main shaft and the motor.

[0022] Through the setting of the switching mechanism, when the main shaft rotates at a high speed, the air inlet hole and the through groove can be closed by the movement of the connecting rod, and the switching holes can be opened by the closing ring, so that the coolant in the liquid cooling box can enter the housing and directly dissipate heat from the main shaft and the motor, further improving the heat dissipation effect. The switching mechanism is used in cooperation with the heat dissipation mechanism, enabling the main shaft to dissipate heat during both low-speed and high-speed rotation. During low-speed rotation, the main shaft drives the cooling fan to dissipate heat, saving energy consumption and ensuring the heat dissipation effect.

[0023] Preferably, the switching mechanism further includes a moving member. The moving member includes a sliding groove opened on the housing. A sliding rod is slidably connected in the sliding groove. The sliding rod is fixedly connected to the connecting rod. An electric push rod is fixedly provided on the housing. The output end of the electric push rod is fixedly connected to the sliding rod.

[0024] Specifically, when in use and the connecting rod needs to move, the electric push rod is started. The output end of the electric push rod drives the sliding rod to move. The sliding rod slides in the sliding groove, and the sliding rod drives the connecting rod to move.

[0025] Through the setting of the moving part, the connecting rod can be automatically driven to move, facilitating the switching between liquid cooling and air cooling, and making the operation more convenient.

[0026] Furthermore, the electric push rod is a prior art and will not be elaborated here.

[0027] Furthermore, the motor is fixedly connected to the closed cover through a fixing ring. The main shaft penetrates through the closed cover. A ceramic ball bearing is arranged on the inner ring surface of the closed cover, and the ceramic ball bearing is sleeved on the main shaft.

[0028] Furthermore, twenty heat dissipation holes are uniformly arranged along the circumferential direction on the protective cover, and the heat dissipation holes are strip-shaped.

[0029] Furthermore, the protective cover is detachably connected to the housing through bolts.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. Through the setting of the housing, the motor and the main shaft can be directly connected, forming a zero-transmission structure, eliminating the intermediate transmission link, improving the transmission efficiency, reducing energy loss, simplifying the structure, reducing the maintenance cost, reducing vibration and noise, and improving the running stability; through the setting of the heat dissipation mechanism, when the main shaft rotates, the heat dissipation fan can be driven to rotate, thereby driving the air flow in the housing, taking out the heat, dissipating heat from the motor and the main shaft, effectively controlling the temperature of the main shaft, avoiding the influence of thermal deformation on the machining accuracy, extending the service life of the motor, supporting long-term continuous operation, and improving the production efficiency.

[0032] 2. Through the setting of the liquid cooling part, when the main shaft rotates at a high speed, the coolant can be conveyed to the main shaft through the liquid inlet pipe, so that the coolant flows in the flow-through groove, taking out the heat generated during the rotation of the main shaft and the heat generated during the operation of the motor, and cooperating with the heat dissipation fan to dissipate heat from the main shaft and the motor, making the heat dissipation effect better.

[0033] 3. By setting the switching mechanism, when the main shaft rotates at high speed, the intake hole and the through groove can be closed through the movement of the connecting rod, and the switching hole can be opened through the sealing ring, so that the cooling liquid in the liquid cooling box can enter the housing to directly dissipate heat from the main shaft and the motor, further improving the heat dissipation effect; the switching mechanism is used in conjunction with the heat dissipation mechanism, so that the main shaft can dissipate heat during both low-speed and high-speed rotation, and when rotating at low speed, the heat dissipation fan is driven by the main shaft to dissipate heat, saving energy consumption and ensuring the heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0035] Figure 2 is an internal structural schematic Figure 1 ;

[0036] Figure 3 is an internal structural schematic Figure 2 ;

[0037] Figure 4 is a front view of the present invention;

[0038] Figure 5 of the present invention Figure 4 is an isometric sectional view taken along line A-A in the present invention;

[0039] Figure 6 of the present invention Figure 4 is an isometric sectional view taken along line B-B in the present invention;

[0040] Figure 7 of the present invention Figure 5 is a partial enlarged view at C in the present invention;

[0041] Figure 8 of the present invention Figure 6 is a partial enlarged view at D in the present invention;

[0042] Figure 9 of the present invention Figure 6 is a partial enlarged view at E in the present invention.

[0043] In the figure:

[0044] 1. Installation mechanism; 11. Housing; 12. Sealing cover; 13. Protection cover; 14. Motor; 15. Main shaft; 16. Bearing; 17. Bearing seat; 18. Through groove;

[0045] 2. Heat dissipation mechanism; 21. Intake hole; 22. Heat dissipation hole; 23. Heat dissipation fan; 24. Liquid cooling member; 241. Flow through groove; 242. Liquid cooling box; 243. Connecting groove; 244. Liquid inlet pipe; 245. Liquid outlet pipe;

[0046] 3. Switching mechanism; 31. Partition ring; 32. Switching hole; 33. Sealing ring; 34. Connecting rod; 35. Moving part; 351. Sliding groove; 352. Sliding rod; 353. Electric push rod. Specific embodiments

[0047] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the protection scope of the present invention.

[0048] As Figures 1 - 5 shown, an embodiment of the present invention discloses an electric spindle of a machine tool, including an installation mechanism 1. The installation mechanism 1 includes a housing 11. One end of the housing 11 is detachably connected with a closing cover 12, and the other end of the housing 11 is detachably connected with a protective cover 13. A motor 14 is arranged in the housing 11, and the output end of the motor 14 is fixedly connected with a main shaft 15. A heat dissipation mechanism 2 is arranged in the housing 11. The heat dissipation mechanism 2 includes an air inlet hole 21 opened on the housing 11, a heat dissipation hole 22 is opened on the protective cover 13, and a heat dissipation fan 23 is fixedly connected to one end of the main shaft 15 close to the protective cover 13.

[0049] Specifically, when using the machine tool, the motor 14 is started. The output end of the motor 14 drives the main shaft 15 to rotate, and the main shaft 15 drives the working parts on the machine tool to rotate to process the parts. During the rotation of the main shaft 15, the heat dissipation fan 23 is driven to rotate. The heat dissipation fan 23 drives the gas in the housing 11 to flow, so that the external gas enters the housing 11 through the air inlet hole 21. Then, under the driving action of the heat dissipation fan 23, the air is discharged from the heat dissipation hole 22, thereby taking out the heat in the housing 11.

[0050] Through the setting of the housing 11, the motor 14 and the main shaft 15 can be directly connected to form a zero-transmission structure, eliminating the intermediate transmission link, improving the transmission efficiency, reducing energy loss, simplifying the structure, reducing the maintenance cost, reducing vibration and noise, and improving the running stability; through the setting of the heat dissipation mechanism 2, the heat dissipation fan 23 can be driven to rotate during the rotation of the main shaft 15, thereby driving the air in the housing 11 to flow, taking out the heat, dissipating heat from the motor 14 and the main shaft 15, effectively controlling the temperature of the main shaft, avoiding the influence of thermal deformation on the machining accuracy, prolonging the service life of the motor, supporting long-term continuous operation, and improving the production efficiency.

[0051] As Figure 5As shown, a bearing 16 is provided in the housing 11. The bearing 16 is a ceramic ball bearing. The bearing 16 is located at one end of the housing 11 close to the protective cover 13. The bearing 16 is sleeved on the main shaft 15. The bearing 16 is arranged on the bearing seat 17, and the bearing seat 17 is fixedly connected to the inner wall of the housing 11.

[0052] Specifically, during use, when the main shaft 15 rotates, the main shaft 15 drives the bearing 16 to rotate.

[0053] Through the arrangement of the bearing 16, the tail end of the main shaft 15 can be supported. And through the arrangement of the ceramic ball bearing, the wear resistance and high temperature resistance of the bearing are improved, the friction force is reduced, and the temperature rise during the rotation of the main shaft 15 is inhibited.

[0054] As Figure 5 shown, twelve through slots 18 are evenly arranged on the bearing seat 17 along the circumferential direction.

[0055] Specifically, during use, when the cooling fan 23 rotates, the gas flows through the through slots 18 in the housing 11, facilitating heat dissipation.

[0056] As Figure 2 、 Figure 3 、 Figure 5 、 Figure 7 shown, the heat dissipation mechanism 2 further includes a liquid cooling member 24 arranged in the housing 11. The liquid cooling member 24 includes a flow-through groove 241 opened in the main shaft 15. A liquid cooling box 242 is rotatably sleeved on the main shaft 15. The liquid cooling box 242 is fixedly connected to the inner wall of the housing 11. Six communication grooves 243 are evenly arranged on the inner wall of the flow-through groove 241 along the circumferential direction. The communication grooves 243 communicate with the liquid cooling box 242. The liquid cooling box 242 is communicated with a liquid inlet pipe 244. The liquid inlet pipe 244 penetrates through the housing 11. The liquid cooling box 242 is communicated with a liquid outlet pipe 245. The liquid outlet pipe 245 penetrates through the housing 11. The liquid inlet pipe 244 and the liquid outlet pipe 245 are communicated with a coolant circulation device.

[0057] Specifically, during use, the coolant circulation device supplies coolant into the liquid cooling box 242 through the liquid inlet pipe 244. The coolant enters the flow-through groove 241 through the communication grooves 243. The coolant flows in the flow-through groove 241 to dissipate heat from the main shaft 15 and also dissipate heat from the motor 14. Then the coolant enters the liquid outlet pipe 245 through the liquid cooling box 242 and then flows back into the coolant circulation device again.

[0058] By providing the liquid cooling member 24, when the main shaft 15 rotates at high speed, coolant can be conveyed to the main shaft 15 through the liquid inlet pipe 244, enabling the coolant to flow in the flow-through groove 241, carrying away the heat generated during the rotation of the main shaft 15 and the heat generated during the operation of the motor 14. In cooperation with the cooling fan 23, heat dissipation of the main shaft 15 and the motor 14 is achieved, resulting in better heat dissipation effect.

[0059] Furthermore, the coolant circulation device is a prior art and will not be elaborated herein.

[0060] As Figures 6 - 9 shown, a switching mechanism 3 is provided in the housing 11. The switching mechanism 3 includes a partition ring 31 slidably connected to the inner wall of the housing 11. The partition ring 31 is located on the side of the air inlet hole 21 closer to the closing cover 12. Six switching holes 32 are evenly formed in the circumferential direction on the side of the liquid cooling box 242 closer to the protective cover 13. A closing ring 33 is provided on the side of the liquid cooling box 242 closer to the protective cover 13. The closing ring 33 closes the switching holes 32. A connecting rod 34 is fixedly connected between the closing ring 33 and the partition ring 31.

[0061] Specifically, in the initial state, the closing ring 33 closes the switching holes 32, and the partition ring 31 is located on the side of the air inlet hole 21 closer to the closing cover 12. When the main shaft 15 needs to rotate at high speed, the connecting rod 34 is slid, causing the connecting rod 34 to move towards the direction closer to the protective cover 13. The connecting rod 34 drives the partition ring 31 to move, and the partition ring 31 closes the air inlet hole 21. At the same time, the connecting rod 34 drives the closing ring 33 to move, and the closing ring 33 closes the switching holes 32. Then, the closing ring 33 closes the through groove 18, and at the same time, the coolant in the liquid cooling box 242 flows into the housing 11 through the switching holes 32, directly contacting the main shaft 15 and the motor 14 to dissipate heat from the main shaft 15 and the motor 14.

[0062] By providing the switching mechanism 3, when the main shaft 15 rotates at high speed, the air inlet hole 21 and the through groove 18 can be closed through the movement of the connecting rod 34, and the switching holes 32 can be opened through the closing ring 33, enabling the coolant in the liquid cooling box 242 to enter the housing 11 and directly dissipate heat from the main shaft 15 and the motor 14, further improving the heat dissipation effect. The switching mechanism 3 cooperates with the heat dissipation mechanism 2, enabling heat dissipation during both the low-speed and high-speed rotation of the main shaft 15. During low-speed rotation, the cooling fan 23 is driven by the main shaft 15 for heat dissipation, saving energy consumption and ensuring the heat dissipation effect.

[0063] As Figure 5 、 Figure 8As shown, the switching mechanism 3 further includes a moving member 35. The moving member 35 includes a sliding groove 351 formed in the housing 11. A sliding rod 352 is slidably connected in the sliding groove 351. The sliding rod 352 is fixedly connected to the connecting rod 34. An electric push rod 353 is fixedly provided on the housing 11. The output end of the electric push rod 353 is fixedly connected to the sliding rod 352.

[0064] Specifically, during use, when it is necessary to move the connecting rod 34, the electric push rod 353 is started. The output end of the electric push rod 353 drives the sliding rod 352 to move. The sliding rod 352 slides in the sliding groove 351, and the sliding rod 352 drives the connecting rod 34 to move.

[0065] Through the arrangement of the moving member 35, the connecting rod 34 can be automatically driven to move, thus facilitating the switching between liquid cooling and air cooling and making the operation more convenient.

[0066] Furthermore, the electric push rod 353 is a prior art and will not be elaborated here.

[0067] Furthermore, the motor 14 is fixedly connected to the closing cover 12 through a fixing ring. The main shaft 15 penetrates through the closing cover 12. A ceramic ball bearing is arranged on the inner ring surface of the closing cover 12. The ceramic ball bearing is sleeved on the main shaft 15.

[0068] Furthermore, twenty heat dissipation holes 22 are evenly arranged on the protection cover 13 in the circumferential direction. The heat dissipation holes 22 are strip-shaped.

[0069] Furthermore, the protection cover 13 is detachably connected to the housing 11 through bolts.

[0070] Furthermore, during the device manufacturing process, strictly control the dimensional tolerances and geometric tolerances of the parts. Conduct dynamic balance tests. Equip with high-resolution encoders or grating scales to monitor the position and speed of the main shaft in real time. Adopt high-performance servo motors to improve the dynamic response speed. Optimize the control system algorithm to shorten the acceleration and deceleration time. Enhance the rigidity of the main shaft to reduce vibration in the dynamic response.

[0071] With the above settings, the transmission efficiency is improved, and the energy loss is reduced. The structure is simplified, and the maintenance cost is lowered. Vibration and noise are reduced, and the running stability is enhanced. Higher rotational speeds are achieved. The bearing life is significantly extended, and the equipment reliability is improved. The machining errors caused by bearing wear are reduced, and the machining accuracy is enhanced. The spindle temperature is effectively controlled, and the influence of thermal deformation on machining accuracy is avoided. The service lives of the motor and bearings are extended. Long-time continuous operation is supported, and the production efficiency is improved. The vibration during high-speed rotation is significantly reduced, and the running stability is enhanced. The machining errors caused by vibration are reduced, and the machining accuracy is improved. The service life of the spindle system is extended. Precise speed and position control are achieved, meeting complex machining requirements. The machining accuracy is improved, and the scrap rate is reduced. Automated production and remote diagnosis are supported, and the production efficiency is enhanced. Rapid acceleration and deceleration are achieved, and the tool change and cutting efficiency are improved. High-speed machining and multi-task switching are supported, and the comprehensive performance of the machine tool is enhanced.

[0072] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0073] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0074] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, so that a process, article, or equipment / device comprising a series of elements not only includes those elements but also includes other elements not explicitly listed, or also includes the elements inherent in these processes, articles, or equipment / device.

[0075] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easily understood by those skilled in the art that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An electric spindle for a machine tool, characterized in that, It includes an installation mechanism (1), and the installation mechanism (1) includes a housing (11). One end of the housing (11) is detachably connected with a closed cover (12), and the other end of the housing (11) is detachably connected with a protective cover (13). A motor (14) is arranged in the housing (11), and the output end of the motor (14) is fixedly connected with a main shaft (15). A heat dissipation mechanism (2) is arranged in the housing (11), and the heat dissipation mechanism (2) includes an air inlet hole (21) opened on the housing (11). A heat dissipation hole (22) is opened on the protective cover (13). One end of the main shaft (15) close to the protective cover (13) is fixedly connected with a heat dissipation fan (23). A bearing (16) is arranged in the housing (11). The bearing (16) is a ceramic ball bearing. The bearing (16) is located at one end of the housing (11) close to the protective cover (13). The bearing (16) is sleeved on the main shaft (15). The bearing (16) is arranged on a bearing seat (17), and the bearing seat (17) is fixedly connected with the inner wall of the housing (11). Twelve through grooves (18) are evenly opened on the bearing seat (17) along the circumferential direction. The heat dissipation mechanism (2) further includes a liquid cooling part (24) arranged in the housing (11). The liquid cooling part (24) includes a circulation groove (241) opened in the main shaft (15). A liquid cooling box (242) is rotatably sleeved on the main shaft (15). The liquid cooling box (242) is fixedly connected with the inner wall of the housing (11). Six communication grooves (243) are evenly opened on the inner wall of the circulation groove (241) along the circumferential direction. The communication grooves (243) are communicated with the liquid cooling box (242). The liquid cooling box (242) is communicated with a liquid inlet pipe (244). The liquid inlet pipe (244) penetrates through the housing (11). The liquid cooling box (242) is communicated with a liquid outlet pipe (245). The liquid outlet pipe (245) penetrates through the housing (11). The liquid inlet pipe (244) and the liquid outlet pipe (245) are communicated with a coolant circulation device. A switching mechanism (3) is arranged in the housing (11). The switching mechanism (3) includes a partition ring (31) slidably connected to the inner wall of the housing (11). The partition ring (31) is located on the side of the air inlet hole (21) close to the closed cover (12). Six switching holes (32) are evenly opened on the side of the liquid cooling box (242) close to the protective cover (13) along the circumferential direction. A closed ring (33) is arranged on the side of the liquid cooling box (242) close to the protective cover (13). The closed ring (33) closes the switching holes (32). A connecting rod (34) is fixedly connected between the closed ring (33) and the partition ring (31).

2. The motorized spindle of a machine tool according to claim 1, wherein, The switching mechanism (3) further includes a moving member (35). The moving member (35) includes a sliding groove (351) formed in the housing (11). A sliding rod (352) is slidably connected in the sliding groove (351). The sliding rod (352) is fixedly connected to the connecting rod (34). An electric push rod (353) is fixedly arranged on the housing (11). The output end of the electric push rod (353) is fixedly connected to the sliding rod (352).

3. The motorized spindle of a machine tool according to claim 2, characterized in that, The motor (14) is fixedly connected to the closed cover (12) through a fixing ring. The main shaft (15) penetrates through the closed cover (12). The inner ring surface of the closed cover (12) is provided with a ceramic ball bearing. The ceramic ball bearing is sleeved on the main shaft (15).

4. The motorized spindle of a machine tool according to claim 3, characterized in that, Twenty heat dissipation holes (22) are uniformly arranged on the protection cover (13) along the circumferential direction. The heat dissipation holes (22) are strip-shaped.

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