Automatic grinding wheel changing servo grinding spindle and grinding wheel changing method

Abstract

The application relates to an automatic grinding wheel changing servo grinding spindle and a grinding wheel changing method, which comprises a spindle shell, a water jacket, a stator coil, a rotor, a spindle core shaft, a dynamic balance spacer sleeve, a front spindle bearing, a spacer sleeve, a front bearing mounting cover, a labyrinth spacer ring, a grinding wheel chuck, a rear spindle mounting base, a rear spindle bearing, a water jacket spacer ring, a floating oil cylinder tool changing mechanism mounting base, a floating oil cylinder tool changing mechanism, a hollow position feedback mechanism and a puller mechanism and the like. The application has the advantages of simple structure, convenient use, built-in stator-rotor structure of the servo grinding spindle, complete unloading tool changing realized by the floating oil cylinder tool changing mechanism, effective protection of the spindle bearing precision, shared gas path for the front end air isolation and the taper hole air blowing of the spindle, automatic switching during the loose puller, safe and reliable positioning and fixing of the grinding wheel chuck by the outer taper surface of the tool changing cylinder, the inner taper surface of the grinding wheel chuck and the steel ball positioning, and multiple butterfly spring locking, high stable constant linear speed grinding realized by the hollow position feedback mechanism at the tail end.

Description

Technical Field

[0001] This invention relates to a grinding spindle, specifically to an automatic grinding wheel changing servo grinding spindle and grinding wheel changing method that features a simple structure, convenient use, effective protection of spindle bearing precision, shared air path for air isolation at the front end of the spindle and air blowing in the tapered hole, and automatic switching when the tool is loosened or pulled out. Background Technology

[0002] With the continuous development of the manufacturing industry, the requirements for manufacturing high-precision parts are becoming increasingly stringent, and multi-face grinding of workpieces in a single clamping has become a development trend. Currently, traditional grinding equipment is only equipped with one type of grinding wheel, and can only grind one surface of the workpiece per clamping. If grinding other surfaces is required, the grinding wheel needs to be manually changed, severely impacting grinding accuracy and efficiency. Furthermore, machining center spindles with automatic tool changers can only hold small tools and cannot accommodate large grinding wheels. Moreover, existing tool changing technologies only have quasi-unloading and tool-setting mechanisms, which cannot completely eliminate the tool-setting force. Each tool change causes some damage to the spindle bearing precision. Therefore, existing technologies cannot meet the tool-changing function requirements of high-precision grinding spindles. In addition, traditional grinding wheel spindles are generally driven by an external motor and belt, resulting in relatively large spindle vibration, and open-loop control cannot achieve constant surface speed grinding, thus failing to meet the requirements of ultra-precision grinding. Summary of the Invention

[0003] To address the aforementioned problems, the main objective of this invention is to provide an automatic grinding wheel changing servo grinding spindle and grinding wheel changing method that features a simple structure, convenient use, effective protection of spindle bearing precision, shared air path for spindle front-end air isolation and taper hole air blowing, and automatic switching when the tool is loosened or pulled out.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution: an automatic grinding wheel changing servo grinding spindle, the automatic grinding wheel changing servo grinding spindle comprising: a spindle housing, a water jacket, a stator coil, a rotor, a spindle mandrel, a dynamic balancing spacer, a rotor locking nut, a front spindle bearing, a spacer, a front bearing mounting cover, a front spindle locking nut, a spiral groove air isolation sleeve, a labyrinth spacer, a grinding wheel chuck, a rear spindle mounting base, a rear spindle bearing, a rear locking nut, a water jacket spacer, a tool-changing mechanism mounting base, a floating hydraulic cylinder tool-changing mechanism, a hollow position feedback mechanism, and a tool-pulling mechanism.

[0005] The water jacket is installed inside the spindle housing, with seals at both ends and fixed by the rear spindle mounting seat via water jacket spacers. Cooling water inlet and outlet devices are located at the left and right ends of the mounting flange at the lower end of the spindle housing. Circulating cooling water enters from the lower end of the spindle housing and flows out from the upper end. The stator coil is interference-fitted onto the inner diameter of the water jacket, and the three-phase coil wires are led out from the notch in the rear spindle mounting seat. The rotor is equipped with dynamic balancing spacers at both ends, with keyways on the spacers for directional mounting to the spindle mandrel. The rotor is interference-fitted onto the outer diameter of the spindle mandrel and fixed by rotor lock nuts. After the shaft, rotor, dynamic balancing spacer, and rotor locking nut are assembled as a whole, their coaxiality is ground and the rotor is dynamically balanced. The front spindle bearing and spacer are installed back-to-back on the front end of the spindle mandrel and fixed to the spindle housing 1 by the front bearing mounting cover, spiral groove air isolation sleeve, and front spindle locking nut. The rear spindle bearing is installed on the rear end of the spindle mandrel and locked by the rear locking nut, and its outer ring end face is not axially limited with the rear spindle mounting seat. The hollow position feedback mechanism is coaxially installed on the rear spindle mounting seat. The floating hydraulic cylinder cutting mechanism is coaxially connected to the hollow position feedback mechanism through the cutting mechanism mounting seat.

[0006] In a specific embodiment of the present invention, the floating hydraulic cylinder cutting mechanism includes a cutting cylinder housing, a hydraulic cylinder mounting base, an upper piston, a lower piston, and a seal.

[0007] The outer shell of the tool-cutting cylinder is mounted on the hydraulic cylinder mounting base, which is connected to the tool-cutting mechanism mounting base. The upper piston is coaxially mounted inside the outer shell of the tool-cutting cylinder, and the lower piston is coaxially mounted outside the upper piston. The upper and lower pistons are equipped with seals. When the spindle rotates, the upper and lower pistons are separated from the spindle spindle. When cutting, when the upper and lower pistons are in contact, the upper and lower oil chamber areas are equal, and the output forces of the upper and lower pistons cancel each other out. The upper and lower pistons are in a high-damping floating state.

[0008] In a specific embodiment of the present invention, the hollow position feedback mechanism includes an encoder mounting plate, an encoder adjusting pad, an encoder, an AB phase gear disk, a Z phase gear disk, a gear disk adjusting pad, and a gear disk locking nut; the AB phase gear disk, the Z phase gear disk, and the gear disk adjusting pad are sequentially and coaxially mounted on the outer diameter of the main spindle mandrel and locked by the gear disk locking nut; the encoder is mounted on the encoder mounting plate via the encoder adjusting pad, and the encoder mounting plate is coaxially mounted on the rear main spindle mounting base; the sensing device on the encoder senses the tooth profile change of the AB phase gear disk in real time, and converts the voltage analog signal of the tooth profile change into a digital signal through signal conversion; the Z phase gear disk lacks one tooth profile for the main spindle homing function; the main spindle achieves closed-loop control through position feedback.

[0009] In a specific embodiment of the present invention, multiple sets of butterfly springs are deformed by external pressure and installed on the outer diameter of the cutting tool mandrel, and are fixed by butterfly spring spacers and shaft retaining rings; the lower piston block is installed in the keyway of the main spindle mandrel in a symmetrical arrangement; the upper piston block is installed in the keyway of the cutting tool mandrel in a symmetrical arrangement; the cutting tool positioning signal disc passes through the main spindle mandrel and is installed at the end of the cutting tool mandrel; the cutting tool cylinder is installed at the end of the cutting tool mandrel; the outer diameter of the cutting tool cylinder and the inner hole of the main spindle mandrel are made of high-hardness material, which can fit with high precision and slide relative to each other; the locking steel ball is installed in the ball hole at the end of the main spindle mandrel and is located between the grinding wheel chuck and the outer conical surface of the cutting tool cylinder, and the automatic loosening and locking of the grinding wheel is achieved by the up and down movement of the locking steel ball.

[0010] In a specific embodiment of the present invention, the spiral groove air isolation and tapered hole blowing at the front end of the grinding spindle share a common air passage. Compressed air enters the inside of the cutting cylinder through the outer shell of the cutting cylinder, the upper piston, the spindle mandrel, and the cutting mandrel. When the spindle is in the tool release state, the air outlet A of the cutting cylinder is connected to the air outlet B of the spindle mandrel, and the spindle automatically switches to the tapered hole blowing mode and closes the air isolation to ensure blowing pressure. When the spindle is in the tool draw state, the air outlet A of the cutting cylinder is connected to the air outlet C of the spindle mandrel, and the spindle automatically switches to the air isolation mode and closes the tapered hole blowing mode. Compressed air enters the gap between the spiral groove air isolation sleeve and the front bearing mounting cover, forming an air barrier to prevent coolant from entering the spindle. When the spindle rotates, the reverse spiral groove on the spiral groove air isolation sleeve pumps viscous air out from the inside.

[0011] A method for changing grinding wheels using an automatic grinding wheel-changing servo grinding spindle includes the following steps: Tool loosening process: Before changing the grinding wheel, multiple sets of butterfly springs are partially compressed, and the grinding wheel is in a locked state; when the system issues a grinding wheel change command, high-pressure hydraulic oil is input externally. The hydraulic oil enters the tool-changing cylinder through the upper and lower oil ports on the outer shell of the tool-changing cylinder. The upper and lower pistons move towards each other rapidly and contact the upper and lower piston levers. The multiple sets of butterfly springs are further compressed, but not completely compressed. At this time, the output force of the upper and lower pistons is equal to the spring force of the multiple sets of butterfly springs, increasing with the increase of spring force; when the upper piston contacts the lower piston... Since the upper and lower oil chambers have equal areas, the output forces of the upper and lower pistons cancel each other out. The output forces of the upper and lower pistons are no longer equal to the spring forces of multiple butterfly springs. The upper and lower pistons are in a high-damping floating state, and the combined force does not act on the outer shell of the tool-cutting cylinder. Therefore, the front spindle bearing is not affected by the tool-cutting force, and the tool-cutting process can achieve complete unloading. The upper piston lever moves the tool-cutting mandrel and tool-cutting cylinder downwards. The outer conical surface of the tool-cutting cylinder and the inner conical surface of the grinding wheel chuck separate from the locking steel ball. The positioning surface of the grinding wheel chuck disengages from the spindle mandrel under the action of gravity. At the same time, the air outlet A of the tool-cutting cylinder is connected to the air outlet B of the spindle mandrel, and the spindle switches to the conical hole blowing mode.

[0012] Tool changing process: When the spindle reaches the position of the new grinding wheel chuck and is ready to automatically change the grinding wheel, the floating cylinder tool changing mechanism stops inputting high-pressure hydraulic oil and the pneumatic reset port is opened. Compressed gas forces the upper piston and lower piston to reset, the lower piston and lower piston lever separate, and the upper piston and upper piston lever separate. The compression force of multiple sets of disc springs forces the outer conical surface of the tool changing cylinder to move upward. The outer conical surface of the tool changing cylinder forces the locking steel ball to move outward. The locking steel ball moves outward and contacts the inner conical surface of the grinding wheel chuck, forcing the chuck positioning surfaces of the grinding wheel chuck and the spindle mandrel to contact and lock each other. The tool changing position signal disk follows the movement of the tool changing mandrel and outputs a tool changing position completion signal. At this time, the air outlet A of the tool changing cylinder is connected to the air outlet C of the spindle mandrel, and the spindle switches to air isolation mode.

[0013] The positive and progressive effects of this invention are as follows: Compared with common technologies, the automatic grinding wheel changing servo grinding spindle and grinding wheel changing method provided by this invention have the following advantages:

[0014] This invention features a simple structure and ease of use. The servo grinding spindle employs a built-in stator-rotor structure to minimize the transmission chain. A floating hydraulic cylinder tool-cutting mechanism enables complete unloading during tool cutting, effectively protecting the spindle bearing precision. The front-end air isolation and tapered hole air blowing share a single air path, automatically switching when the tool is released, greatly simplifying the air path structure. Furthermore, the compressed gas always passes through the spindle shaft, significantly increasing the spindle rotor's heat dissipation capacity. During spindle rotation, the reverse spiral grooves on the surface of the spiral groove air isolation sleeve pump viscous air outwards, enhancing the air isolation effect. Positioning is achieved through the outer conical surface of the tool-cutting cylinder, the inner conical surface of the grinding wheel chuck, and locking steel balls, secured by multiple sets of disc springs, ensuring safe and reliable grinding wheel positioning. The servo grinding spindle is equipped with a hollow position feedback mechanism at its end, enabling highly stable constant surface speed grinding. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the present invention;

[0016] Figure 2 A schematic diagram of a cutting mechanism with a floating hydraulic cylinder;

[0017] Figure 3 This is a schematic diagram of the position feedback mechanism;

[0018] Figure 4 This is a schematic diagram of the broaching mechanism;

[0019] Figure 5 A schematic diagram showing the switching between conical orifice air blowing and spiral groove air isolation.

[0020] The following are the names corresponding to the reference numerals in this invention:

[0021] 1. Shaft housing, 2. Water jacket, 3. Stator coil, 4. Rotor, 5. Main spindle core, 6. Dynamic balancing spacer, 7. Rotor locking nut, 8. Front main spindle bearing, 9. Spacer, 10. Front bearing mounting cover, 11. Front main spindle locking nut, 12. Spiral groove air isolation sleeve, 13. Labyrinth spacer, 14. Grinding wheel chuck, 15. Rear main spindle mounting seat, 16. Rear main spindle bearing, 17. Water jacket spacer, 18. Tool-cutting mechanism mounting seat, 19. Floating cylinder tool-cutting mechanism, 100. Hollow position feedback mechanism, 200. Tool-pulling mechanism, 300.

[0022] 101 housing of the cutter cylinder, 102 mounting base of the hydraulic cylinder, 103 upper piston, 104 lower piston, and 105 seal;

[0023] Encoder mounting plate 201, encoder adjusting pad 202, encoder 203, AB phase gear disk 204, Z phase gear disk 205, gear disk adjusting pad 206 and gear disk locking nut 207;

[0024] Cutting mandrel 301, upper piston lever 302, lower piston lever 303, multiple sets of butterfly springs 304, butterfly spring spacer rings 305, shaft retaining rings 306, cutting position signal disc 307, cutting cylinder 308, locking steel ball 309. Detailed Implementation

[0025] The preferred embodiments of the present invention are given below with reference to the accompanying drawings to illustrate the technical solution of the present invention in detail.

[0026] Figure 2 This is a schematic diagram of the overall structure of the present invention. Figure 3 This is a schematic diagram of the improved pump body assembly of the present invention, as shown below. Figure 2-3As shown: This invention proposes a highly reliable horizontal chemical axial flow pump structure, which includes a main shaft housing 1, a water jacket 2, a stator coil 3, a rotor 4, a main shaft mandrel 5, a dynamic balancing spacer 6, a rotor locking nut 7, a front main shaft bearing 8, a spacer 9, a front bearing mounting cover 10, a front main shaft locking nut 11, a spiral groove air isolation sleeve 12, a labyrinth spacer 13, a grinding wheel chuck 14, a rear main shaft mounting seat 15, a rear main shaft bearing 16, a rear locking nut 17, a water jacket spacer 18, a cutter mechanism mounting seat 19, a floating cylinder cutter mechanism 100, a hollow position feedback mechanism 200, and a cutter pulling mechanism 300, etc. The floating cylinder cutting mechanism 100 consists of a cutting cylinder housing 101, a cylinder mounting base 102, an upper piston 103, a lower piston 104, and a seal 105. The hollow position feedback mechanism 200 consists of an encoder mounting plate 201, an encoder adjusting pad 202, an encoder 203, an AB phase gear plate 204, a Z phase gear plate 205, a gear plate adjusting pad 206, and a gear plate locking nut 207. The cutting mechanism 300 consists of a cutting mandrel 301, an upper piston lever 302, a lower piston lever 303, multiple sets of butterfly springs 304, butterfly spring spacers 305, a shaft retaining ring 306, a cutting position signaling plate 307, a cutting cylinder 308, and a locking steel ball 309.

[0027] See Figure 1 The water jacket 2 is installed inside the spindle housing 1, with seals at both ends and fixed by the rear spindle mounting seat 15 via water jacket spacers 18. Cooling water inlet and outlet devices are located at the left and right ends of the mounting flange at the lower end of the spindle housing 1. Circulating cooling water enters from the lower end of the spindle housing 1 and flows out from the upper end, effectively reducing the internal temperature of the spindle. The stator coil 3 is interference-fitted onto the inner diameter of the water jacket 2, and the three-phase coil wires are led out from the notch in the rear spindle mounting seat 15. The rotor 4 is equipped with dynamic balancing spacers 6 at both ends. The dynamic balancing spacers 6 are equipped with keyways for directional installation with the spindle mandrel 5. The rotor 4 is interference-fitted onto the outer diameter of the spindle mandrel 5 and fixed by rotor locking nuts 7. The spindle mandrel 5, rotor 4, dynamic balancing spacers 6, and rotor... After the locking nut 7 is installed as a whole, the coaxiality is adjusted and the rotor is dynamically balanced. The front spindle bearing 8 and the spacer 9 are installed back to back on the front end of the spindle mandrel 5 and fixed to the spindle housing 1 by the front bearing mounting cover 10, the spiral groove air isolation sleeve 12 and the front spindle locking nut 11. The rear spindle bearing 16 is installed at the rear end of the spindle mandrel 5 and locked by the rear locking nut 17. Its outer ring end face is not axially limited with the rear spindle mounting seat 15 to release the thermal deformation of the spindle. The hollow position feedback mechanism 200 is coaxially installed on the rear spindle mounting seat 15. The hollow position feedback mechanism 200 can realize high-stability constant linear speed grinding. The floating oil cylinder tool-cutting mechanism 100 is coaxially connected to the hollow position feedback mechanism 200 through the tool-cutting mechanism mounting seat 19.

[0028] See Figure 2The cutter cylinder housing 101 is mounted on the cylinder mounting base 102, which is connected to the cutter mechanism mounting base 19. The upper piston 103 is coaxially mounted inside the cutter cylinder housing 101, and the lower piston 104 is coaxially mounted outside the upper piston 103. Both the upper and lower pistons 103 and 104 are equipped with seals 105. When the spindle rotates, the upper and lower pistons 103 and 104 are separated from the spindle core 5 and do not rotate with it, effectively protecting the seals 105. During cutter removal, when the upper piston 103 and lower piston 104 contact, because the upper and lower oil chamber areas are equal, the output forces of the upper and lower pistons cancel each other out, and the upper and lower pistons are in a high-damping floating state. Therefore, the effective area of ​​the upper and lower pistons and the cylinder input pressure do not need to be perfectly matched with the spring forces of the multiple sets of butterfly springs 304 to achieve complete unloading and cutter removal, greatly improving the compatibility of the floating cylinder cutter removal mechanism 100.

[0029] See Figure 3 The AB phase gear disk 204, Z phase gear disk 205, and gear disk adjusting shim 206 are coaxially mounted on the outer diameter of the main spindle core 5 and locked in place by the gear disk locking nut 207. The encoder 203 is mounted on the encoder mounting plate 201 via the encoder adjusting shim 202, and the encoder mounting plate 201 is coaxially mounted on the rear main spindle mounting seat 15. The sensing device on the encoder 203 can sense the tooth profile change of the AB phase gear disk 204 in real time, and convert the voltage analog signal of the tooth profile change into a digital signal through signal conversion. The Z phase gear disk 205 lacks one tooth profile for the main spindle homing function. The main spindle can achieve closed-loop control through position feedback, which greatly improves the rated torque of the main spindle.

[0030] See Figure 4 Multiple sets of butterfly springs 304 are deformed by external pressure and installed on the outer diameter of the cutting tool mandrel 301, and are limited and fixed by butterfly spring spacers 305 and shaft retaining rings 306; the lower piston block 303 is installed in the keyway of the main spindle mandrel 5 in a symmetrical arrangement; the upper piston block 302 is installed in the keyway of the cutting tool mandrel 301 in a symmetrical arrangement; the cutting tool positioning signal disc 307 passes through the main spindle mandrel 5 and is installed at the end of the cutting tool mandrel 301; the cutting tool cylinder 308 is installed at the end of the cutting tool mandrel 301; the outer diameter of the cutting tool cylinder 308 and the inner hole of the main spindle mandrel 5 are made of high-hardness material, which can fit with high precision and slide relative to each other; the locking steel ball 309 is installed in the ball hole at the end of the main spindle mandrel 5 and is located between the grinding wheel chuck 14 and the outer conical surface of the cutting tool cylinder 308, and the automatic loosening and locking of the grinding wheel is achieved by the up and down movement of the locking steel ball 309.

[0031] See Figure 4 , 5The helical groove air isolation and tapered hole blowing at the front end of the grinding spindle share a common air passage. Compressed air enters the inside of the cutting cylinder 308 through the cutting cylinder housing 101, upper piston 103, spindle mandrel 5, and cutting mandrel 301. When the spindle is in the tool release state, the air outlet A of the cutting cylinder 308 is connected to the air outlet B of the spindle mandrel 5, and the spindle automatically switches to tapered hole blowing mode and closes the air isolation to ensure blowing pressure. When the spindle is in the tool draw state, the air outlet A of the cutting cylinder 308 is connected to the air outlet C of the spindle mandrel 5, and the spindle automatically switches to air isolation mode and closes the tapered hole blowing mode. Compressed air enters the gap between the helical groove air isolation sleeve 12 and the front bearing mounting cover 10, forming an air barrier to prevent coolant from entering the spindle. When the spindle rotates, the reverse helical groove on the helical groove air isolation sleeve 12 pumps viscous air out from the inside, increasing the air isolation effect.

[0032] The specific automatic grinding wheel changing process is described below:

[0033] The tool loosening process: Before changing the grinding wheel, multiple sets of butterfly springs 304 are partially compressed, and the grinding wheel is in a locked state. When the system issues a grinding wheel replacement command, high-pressure hydraulic oil is input externally. The hydraulic oil enters the tool-changing cylinder through the upper and lower oil ports of the tool-changing cylinder housing 101. The upper piston 103 and lower piston 104 move towards each other and quickly approach and contact the upper and lower piston levers. The multiple sets of butterfly springs 304 are further compressed (not completely compressed). At this time, the output force of the upper and lower pistons is equal to the spring force of the multiple sets of butterfly springs 304, and increases with the increase of spring force. When the upper piston 103 and lower piston 104 contact each other, since the upper and lower oil chamber areas are equal, the output forces of the upper and lower pistons cancel each other out, and the output force of the upper and lower pistons is no longer equal to the multiple sets of butterfly springs 304. The spring force of the butterfly spring 304 causes the upper and lower pistons to be in a high-damping floating state. The combined force does not act on the outer shell 101 of the tool-cutting cylinder, so the front spindle bearing 8 is not affected by the tool-cutting force, and the tool-cutting process can achieve complete unloading. The upper piston lever 302 drives the tool-cutting mandrel 301 and the tool-cutting cylinder 308 to move down. The outer conical surface of the tool-cutting cylinder 308 and the inner conical surface of the grinding wheel chuck 14 separate from the locking steel ball 309. The chuck positioning surface of the grinding wheel chuck 14 disengages from the spindle mandrel 5 under the action of gravity. At the same time, the air outlet A of the tool-cutting cylinder 308 is connected to the air outlet B of the spindle mandrel 5, and the spindle switches to the conical hole blowing mode.

[0034] Tool changing process: When the spindle reaches the new grinding wheel chuck position and is ready for automatic grinding wheel change, the floating cylinder tool changing mechanism 100 stops inputting high-pressure hydraulic oil, and the pneumatic reset port is opened. Compressed gas forces the upper piston 103 and lower piston 104 to reset, the lower piston 104 and lower piston lever 303 separate, and the upper piston 103 and upper piston lever 302 separate. The compression force of multiple sets of butterfly springs 304 forces the outer conical surface of the tool changing cylinder 308 to move upward. The outer conical surface of the tool changing cylinder 308 forces the locking steel ball 309 to move outward. The locking steel ball 309 moves outward and contacts the inner conical surface of the grinding wheel chuck 14, forcing the chuck positioning surfaces of the grinding wheel chuck 14 and the spindle mandrel 5 to contact and lock together. The tool changing position signal disk 307 moves with the tool changing mandrel 301 and outputs a tool changing position completion signal. At this time, the air outlet A of the tool changing cylinder 308 is connected to the air outlet C of the spindle mandrel 5, and the spindle switches to air isolation mode.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. An automatic wheel-changing servo grinding spindle, characterized in that: The automatic wheel-changing servo grinding spindle includes: spindle housing, water jacket, stator coil, rotor, spindle mandrel, dynamic balancing spacer, rotor locking nut, front spindle bearing, spacer, front bearing mounting cover, front spindle locking nut, spiral groove air isolation sleeve, labyrinth spacer, grinding wheel chuck, rear spindle mounting base, rear spindle bearing, rear locking nut, water jacket spacer, tool-changing mechanism mounting base, floating cylinder tool-changing mechanism, hollow position feedback mechanism, and tool-pulling mechanism; The water jacket is installed inside the spindle housing, with seals at both ends and fixed by the rear spindle mounting seat via water jacket spacers. Cooling water inlet and outlet devices are located at the left and right ends of the mounting flange at the lower end of the spindle housing. Circulating cooling water enters from the lower end of the spindle housing and flows out from the upper end. The stator coil is interference-fitted onto the inner diameter of the water jacket, and the three-phase coil wires are led out from the notch in the rear spindle mounting seat. The rotor is equipped with dynamic balancing spacers at both ends, with keyways on the spacers for directional mounting to the spindle mandrel. The rotor is interference-fitted onto the outer diameter of the spindle mandrel and fixed by rotor lock nuts. After the shaft, rotor, dynamic balancing spacer, and rotor locking nut are assembled as a whole, their coaxiality is ground and the rotor is dynamically balanced. The front spindle bearing and spacer are mounted back-to-back on the front end of the spindle mandrel and fixed to the spindle housing by the front bearing mounting cover, spiral groove air isolation sleeve, and front spindle locking nut. The rear spindle bearing is mounted on the rear end of the spindle mandrel and locked by the rear locking nut, with its outer ring end face not axially limited to the rear spindle mounting seat. The hollow position feedback mechanism is coaxially mounted on the rear spindle mounting seat. The floating hydraulic cylinder tool-cutting mechanism is coaxially connected to the hollow position feedback mechanism through the tool-cutting mechanism mounting seat. The floating hydraulic cylinder cutting mechanism includes a cutting cylinder housing, a hydraulic cylinder mounting base, an upper piston, a lower piston, and seals; The outer shell of the cutter cylinder is mounted on the cylinder mounting base, which is connected to the cutter mechanism mounting base. The upper piston is coaxially mounted inside the outer shell of the cutter cylinder, and the lower piston is coaxially mounted outside the upper piston. The upper piston and the lower piston are equipped with seals. The hollow position feedback mechanism includes an encoder mounting plate, an encoder adjusting pad, an encoder, an AB phase gear disk, a Z phase gear disk, a gear disk adjusting pad, and a gear disk locking nut. The AB phase gear disk, Z phase gear disk, and gear disk adjusting pad are coaxially mounted on the outer diameter of the main spindle and locked by the gear disk locking nut. The encoder is mounted on the encoder mounting plate via the encoder adjusting pad, and the encoder mounting plate is coaxially mounted on the rear main spindle mounting base. Multiple sets of butterfly springs are deformed by external pressure and installed on the outer diameter of the cutting tool spindle, and are fixed by butterfly spring spacers and shaft retaining rings; the lower piston block is installed in the keyway of the main spindle in a symmetrical arrangement; the upper piston block is installed in the keyway of the cutting tool spindle in a symmetrical arrangement.

2. The automatic wheel-changing servo grinding spindle according to claim 1, characterized in that: When the spindle rotates, the upper and lower pistons are separated from the spindle mandrel. When the tool is being cut, the upper and lower pistons come into contact, the areas of the upper and lower oil chambers are equal, and the output forces of the upper and lower pistons cancel each other out. The upper and lower pistons are in a high-damping floating state. The internal force generated by the upper and lower pistons only overcomes the spring force of multiple sets of butterfly springs. The effective area of ​​the upper and lower pistons and the input pressure of the oil cylinder do not need to be completely matched with the spring force of multiple sets of butterfly springs to achieve complete unloading and tool cutting, which greatly improves the compatibility of the floating oil cylinder tool cutting mechanism.

3. The automatic wheel-changing servo grinding spindle according to claim 2, characterized in that: The encoder's sensing device detects the tooth profile changes of the AB phase gear disk in real time, and converts the analog voltage signal of the tooth profile change into a digital signal through signal conversion; the Z phase gear disk lacks a tooth profile for the spindle homing function; the spindle achieves closed-loop control through position feedback.

4. The automatic wheel-changing servo grinding spindle according to claim 3, characterized in that: The tool-setting signal disc passes through the spindle mandrel and is installed at the end of the tool-setting mandrel; the tool-setting cylinder is installed at the end of the tool-setting mandrel; the outer diameter of the tool-setting cylinder and the inner hole of the spindle mandrel are made of high-hardness material, which can fit together with high precision and slide relative to each other; the locking steel ball is installed in the ball hole at the end of the spindle mandrel and is located between the grinding wheel chuck and the outer conical surface of the tool-setting cylinder. The automatic loosening and locking of the grinding wheel is achieved by the up and down movement of the locking steel ball.

5. The automatic wheel-changing servo grinding spindle according to claim 4, characterized in that: The helical groove air isolation and tapered hole blowing at the front end of the grinding spindle share a common air passage. Compressed air enters the inside of the cutting cylinder through the cutting cylinder housing, upper piston, spindle mandrel, and cutting mandrel. When the spindle is in the tool release state, the air outlet A of the cutting cylinder is connected to the air outlet B of the spindle mandrel, and the spindle automatically switches to tapered hole blowing mode and closes the air isolation to ensure blowing pressure. When the spindle is in the tool draw state, the air outlet A of the cutting cylinder is connected to the air outlet C of the spindle mandrel, and the spindle automatically switches to air isolation mode and closes the tapered hole blowing mode. Compressed air enters the gap between the helical groove air isolation sleeve and the front bearing mounting cover, forming an air barrier to prevent coolant from entering the spindle. When the spindle rotates, the reverse helical groove on the helical groove air isolation sleeve pumps viscous air out from the inside, increasing the air isolation effect.

6. A grinding wheel changing method using an automatic grinding wheel changing servo grinding spindle as described in claim 5, characterized in that: The method includes the following steps: Tool loosening process: Before changing the grinding wheel, multiple sets of butterfly springs are partially compressed, and the grinding wheel is in a locked state; when the system issues a grinding wheel replacement command, high-pressure hydraulic oil is input externally. The hydraulic oil enters the tool-changing cylinder through the upper and lower oil ports on the outer shell of the cylinder. The upper and lower pistons move towards each other rapidly and contact the upper and lower piston levers. The multiple sets of butterfly springs are further compressed, but not completely compressed. At this time, the output force of the upper and lower pistons is equal to the spring force of the multiple sets of butterfly springs, increasing with the increase of the spring force; when the upper and lower pistons contact, because the areas of the upper and lower oil chambers are equal... The output forces of the upper and lower pistons cancel each other out, and the output forces of the upper and lower pistons are no longer equal to the spring forces of multiple sets of disc springs. The upper and lower pistons are in a high-damping floating state, and the combined force does not act on the outer shell of the tool-cutting cylinder. Therefore, the front spindle bearing is not affected by the tool-cutting force, and the tool-cutting process can achieve complete unloading. The upper piston paddle moves the tool-cutting mandrel and the tool-cutting cylinder downward. The outer conical surface of the tool-cutting cylinder and the inner conical surface of the grinding wheel chuck separate from the locking steel ball. The positioning surface of the grinding wheel chuck is disengaged from the spindle mandrel under the action of gravity. At the same time, the air outlet A of the tool-cutting cylinder is connected to the air outlet B of the spindle mandrel, and the spindle switches to the conical hole blowing mode. Tool changing process: When the spindle reaches the position of the new grinding wheel chuck and is ready to automatically change the grinding wheel, the floating cylinder tool changing mechanism stops inputting high-pressure hydraulic oil and the pneumatic reset port is opened. Compressed gas forces the upper piston and lower piston to reset, the lower piston and lower piston lever separate, and the upper piston and upper piston lever separate. The compression force of multiple sets of disc springs forces the outer conical surface of the tool changing cylinder to move upward. The outer conical surface of the tool changing cylinder forces the locking steel ball to move outward. The locking steel ball moves outward and contacts the inner conical surface of the grinding wheel chuck, forcing the chuck positioning surfaces of the grinding wheel chuck and the spindle mandrel to contact and lock each other. The tool changing position signal disk follows the movement of the tool changing mandrel and outputs a tool changing position completion signal. At this time, the air outlet A of the tool changing cylinder is connected to the air outlet C of the spindle mandrel, and the spindle switches to air isolation mode.

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