A cryogenic medium internal spray type double swing head electric spindle

Abstract

This invention discloses a cryogenic medium internal spray type dual-swivel head electric spindle, including a cryogenic medium internal spray type electric spindle, a cryogenic medium internal spray type A-axis swivel head, and a cryogenic medium internal spray type C-axis swivel head. Through the design of the cryogenic medium internal spray type dual-swivel head electric spindle, a cooling method is achieved by delivering cryogenic medium to the tool tip through the internal cavity channel of the dual-swivel head-electric spindle-tool. The cryogenic medium delivery pipeline inside the dual-swivel head electric spindle adopts a vacuum insulation structure, isolating the potential performance damage to the dual-swivel head and electric spindle caused by extreme low temperatures. In the internal structure of the dual-swivel head electric spindle, the dynamic and static mating surfaces are connected by a low-temperature resistant rotary dynamic seal joint, ensuring good dynamic sealing while also accommodating the multi-axis linkage motion function of the dual-swivel head electric spindle. The cryogenic medium delivery pipeline passes through the center of the swivel head and the electric spindle, realizing reliable medium transmission. The electric spindle adopts a vacuum-insulated tie rod, which not only realizes automatic tool changing but also provides heat insulation.

Description

Technical Field

[0001] This invention belongs to the field of CNC machine tool functional component design technology, and relates to an ultra-low temperature medium internal spray type double swing head electric spindle. Background Technology

[0002] In aerospace, petrochemical, and other fields, advanced materials such as high-temperature alloys and titanium alloys have become the preferred materials for key components such as aero-engines, gas turbine blades, impellers, and integral bladed disks due to their superior performance. Given the complex curved surface structures of these components, the high cutting temperatures in the machining area, and the poor surface quality under low-speed cutting, the development of advanced cooling, high-speed cutting, and multi-axis machining technologies is particularly urgent. An internal spray cooling method, which delivers ultra-low temperature media such as liquid nitrogen (-196℃) to the tool tip through an internal channel between a double-swivel head, electric spindle, and tool, not only achieves immediate and deep cooling of the cutting area, effectively reducing the cutting temperature, but also ensures the quality and efficiency of complex curved surface components under high-speed machining, meeting the urgent needs of key fields for new technologies in high-end component machining.

[0003] Therefore, the cryogenic medium internal spray type double-swivel head electric spindle has become one of the components for realizing high-speed multi-axis linkage machining at cryogenic temperatures. However, the development of the cryogenic medium internal spray type double-swivel head electric spindle faces many challenges. For example, the complex internal structure and motion of the double-swivel head electric spindle not only pose challenges to the design of the cryogenic medium conveying structure, but also significantly increase the difficulty of dynamic sealing and heat insulation. Once the cryogenic medium leaks or the heat insulation is insufficient, it will cause serious problems such as frosting, deformation, and lubrication failure, endangering the stable operation of the equipment. At the same time, the compatible design of the electric spindle tool changer and the cryogenic medium transmission structure must take into account both motion coordination and heat insulation sealing, which is extremely technically difficult. Therefore, overcoming the above-mentioned challenges is extremely important for the development of the cryogenic medium internal spray type double-swivel head electric spindle.

[0004] Currently, several structural forms have been invented by domestic and foreign institutions for internally cooled double-swivel head spindles. In 2021, Dalian University of Technology disclosed "an ultra-low temperature cooling medium internal spray mechanical spindle" in invention patent 202110373295.7. This device achieves ultra-low temperature medium transmission through the vacuum pipeline inside the spindle. However, due to the static design of the vacuum pipeline, it cannot be compatible with traditional tool-changing mechanisms, resulting in the lack of automatic tool changing function. In addition, this device is a mechanical spindle and does not involve a double-swivel head structure. In 2023, Hunan Huazhong CNC Machine Tool Co., Ltd. disclosed "a five-axis swivel head with both internal cooling and hollow high-pressure water outlet" in invention patent 202311298970.X. This device achieves the introduction of cooling water from the tail end of the spindle by designing a cooling channel in the stator of the spindle motor, and finally flows to the hollow channel inside the tool and is sprayed out in a high-pressure form. However, the cooling medium is water, and the design difficulty of the device is far less than that of ultra-low temperature medium. Moreover, the cooling water does not pass through the inside of the swivel head, so its heat insulation and sealing difficulty is relatively small. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies or practical application needs by proposing a cryogenic medium internal spray type double-swivel head electric spindle. It overcomes the challenges of cryogenic medium transmission, heat insulation, and dynamic sealing within the double-swivel head and electric spindle, and effectively integrates the cryogenic medium internal spray cooling function with the double-swivel head electric spindle. It can provide a reliable core functional component for cryogenic high-speed multi-axis linkage machining.

[0006] The technical solution of the present invention:

[0007] A cryogenic medium internal spray type double-swivel head electric spindle mainly consists of a cryogenic medium internal spray type electric spindle 2.8, a cryogenic medium internal spray type A-axis swivel head section, and a cryogenic medium internal spray type C-axis swivel head section. The cryogenic medium internal spray type A-axis swivel head section includes a first cryogenic medium internal spray type A-axis swivel head section and a second cryogenic medium internal spray type A-axis swivel head section respectively disposed on the left and right sides. The first cryogenic medium internal spray type A-axis swivel head section includes a first vacuum mandrel 2.1, a first deep groove ball bearing 2.2, a first bearing end cover 2.3, a first A-axis torque motor rotor 2.4, a first A-axis torque motor stator 2.5, a second motor base 2.6, a first encoder 2.7, and a spindle box 2.9. The second cryogenic medium internal spray type A-axis swivel head section includes a second vacuum mandrel. 2.13, Second deep groove ball bearing; 2.14, Second bearing end cover; 2.15, Second A-axis torque motor stator; 2.16, Second A-axis torque motor rotor; 2.17, Third motor mount; 2.18, Second low-temperature resistant rotary dynamic seal joint; 2.19, Second encoder; 2.20, and A-axis rear end cover; The cryogenic medium internal spray type C-axis swing head includes: 2.10, Housing; 2.25, Third vacuum spindle; 2.26, Third deep groove ball bearing; 2.27, Transition plate; 2.28, C-axis torque motor rotor; 2.29, C-axis torque motor stator; 2.30, Fourth motor mount; 2.31, Upper end cover; 2.32, Fourth deep groove ball bearing; 2.33, C-axis bearing seat; 2.34, Third low-temperature resistant rotary dynamic seal joint; and 2.35, Third bearing end cover.

[0008] Assembling the cryogenic dielectric electric spindle 2.8: The first angular contact bearing 1.3 is assembled between the spindle core 1.1 and the front bearing housing 1.2 with a transition fit; the first bushing 1.4 is pushed in along the spindle core 1.1 until it abuts against the inner ring of the first angular contact bearing 1.3; the second angular contact bearing 1.5, the second bushing 1.6, the third angular contact bearing 1.7, and the third bushing 1.8 are then pushed in along the front end of the spindle core 1.1 until they abut against the first bushing 1.4, wherein the inner rings of the third angular contact bearing 1.7 and the second angular contact bearing 1.5 are both transition fits with the spindle core 1.1, and the outer rings of the third angular contact bearing 1.7 and the second angular contact bearing 1.5 are transition fits with the front bearing housing 1.2. .2 is a transition fit; the outer ring of the third angular contact bearing 1.7 is locked with the first bearing cap 1.9, and the third bushing 1.8 is pressed with the second bearing cap 1.10, thereby indirectly locking the inner ring of the third angular contact bearing 1.7; the spindle motor rotor 1.13 is installed on the spindle core 1.1; the spindle motor stator 1.12 is installed on the first motor mount 1.11, and the first motor mount 1.11 is connected to the front bearing housing 1.2 by bolts; the rear bearing housing 1.14 is fixed to the first motor mount 1.11 by bolts; the fourth bushing 1.15, the fourth angular contact bearing 1.16, and the fifth bushing are sequentially installed along the rear end of the spindle core 1.1. 1.17. The fifth angular contact bearing 1.18, wherein the inner rings of the fourth angular contact bearing 1.16 and the fifth angular contact bearing 1.18 are transition-fitted with the spindle core 1.1, and the outer rings are transition-fitted with the rear bearing housing 1.14. The inner ring of the fifth angular contact bearing 1.18 is locked with the third bearing cap 1.19; the rear end cap 1.20 is connected to the rear bearing housing 1.14 by bolts; the broaching disc spring 1.22 is installed on the vacuum spacer broaching rod 1.23, and the vacuum spacer broaching rod 1.23 is installed into the spindle core 1.1; then, the tool-changing cylinder 1.21 is installed on the rear end cap 1.20 by bolts; one end of the vacuum spacer broaching rod 1.23 is connected to the broaching disc spring 1.22. The claw 1.27 is connected to the other end, and the first low-temperature resistant rotary dynamic sealing joint 1.24 is connected to the end plug 1.25 by a threaded connection; the end plug 1.25 is connected to the first vacuum hose 2.11 through the connecting pipe 1.26; the heat insulation sleeve 1.28 is connected to the hollow tool holder 1.29 by a thread, and then the spring collet 1.30 is placed into the hollow tool holder 1.29, and the internal cooling tool 1.32 is inserted into the spring collet 1.30 until it abuts against the heat insulation sleeve 1.28, and then locked with the locking nut 1.31; the hollow tool holder 1.29 is installed into the spindle core 1.1; the cryogenic dielectric electric spindle 2.8 is fixed to the spindle box 2.10 by a bolt connection;

[0009] Assembly of the first cryogenic medium internal spray type A-axis oscillating head: The first vacuum spindle 2.1 is fixedly connected to the spindle box 2.9 with bolts; the first vacuum spindle 2.1 is connected to the housing 2.10 via the first deep groove ball bearing 2.2, wherein the inner ring of the bearing has a transition fit with the first vacuum spindle 2.1, and the outer ring of the first deep groove ball bearing 2.2 has a transition fit with the housing 2.10; the first bearing end cover 2.3 is pressed against the outer ring of the first deep groove ball bearing 2.2; the first A-axis torque motor stator 2.5 is fixed on the second motor base 2.6, and the second motor base 2.6 is fastened to the housing 2.10; the first A-axis torque motor rotor 2.4 is fixed on the first vacuum spindle 2.1, wherein the first A-axis torque motor stator 2.5 and the A-axis torque motor rotor 2.4 have a clearance fit; the first encoder 2.7 is connected to the second motor base 2.6.

[0010] Assembly of the second cryogenic medium internal spray type A-axis oscillating head: The second vacuum spindle 2.13 is fixedly connected to the spindle box 2.9 by bolts, allowing the spindle box 2.9 to rotate around the A-axis; the second vacuum spindle 2.13 is connected to the first vacuum hose 2.11 by a threaded connection through the first copper connector 2.12; the second vacuum spindle 2.13 is connected to the housing 2.10 through the second deep groove ball bearing 2.14, wherein the inner ring of the bearing has a transition fit with the second vacuum spindle 2.13, and the outer ring of the bearing has a transition fit with the housing 2.10; the second bearing end cover 2.15 is pressed against the outer ring of the second deep groove ball bearing 2.14; the second A-axis torque motor stator 2.16 is fixed on the third motor base 2.18, and the third motor... The base 2.18 is fastened to the housing 2.10; the rotor 2.17 of the second A-axis torque motor is fixed on the second vacuum spindle 2.13, wherein the stator 2.16 of the second A-axis torque motor and the rotor 2.17 of the second A-axis torque motor are in clearance fit; the second encoder 2.20 is connected to the third motor base 2.18; the second low-temperature resistant rotary dynamic seal joint 2.19 is connected to the second vacuum spindle 2.13 by means of threads, with the rotating end connected to the second vacuum spindle 2.13 and the stationary end connected to the center hole of the A-axis rear end cover 2.21; the A-axis rear end cover 2.21 is fixed to the third motor base 2.18, and the second vacuum hose 2.23 is inserted into the hole 2.d of the A-axis rear end cover and connected to the stationary end of the second low-temperature resistant rotary dynamic seal joint 2.19 by means of threads;

[0011] Assembly of the C-axis swing head with internal spray for cryogenic medium: The third deep groove ball bearing 2.26 is installed onto the upper cylindrical surface 2.c of the housing 2.10 using a transition fit; one end of the second copper connector 2.24 is threaded to the second vacuum hose 2.23, and the other end is connected to the third vacuum mandrel 2.25; the bottom of the third vacuum mandrel 2.25 is bolted to the upper plane 2.b of the housing 2.10, while simultaneously tightening the third deep groove ball bearing 2.2. 6. The inner ring; the protective plate 2.22 is fixed to the housing 2.10 by bolt connection; the C-axis torque motor stator 2.29 is fixed to the fourth motor base 2.30 by bolt connection; the fourth motor base 2.30 is connected and fixed to the transition plate 2.27; the transition plate 2.27 is pushed into the outer ring of the third deep groove ball bearing 2.26 in a transition fit until the groove surface 2.a of the transition plate presses against the outer ring of the third deep groove ball bearing 2.26, at which point the third vacuum mandrel 2.2... 5. The center hole of the transition plate 2.27 is clearance-fitted; the C-axis torque motor rotor 2.28 is mounted on the third vacuum spindle 2.25, and then the upper end cover 2.31 is fixed to the upper side of the fourth motor base 2.30 by bolt connection; the C-axis bearing housing 2.33 is pushed into the center hole of the upper end cover 2.31 and fixed to the upper end cover 2.31 by bolts; the fourth deep groove ball bearing 2.32 is assembled with a transition fit between the C-axis bearing housing 2.33 and the third vacuum spindle 2.2. Between 5; connect the third low-temperature resistant rotary dynamic seal joint 2.34 to the third vacuum mandrel 2.25 via a threaded connection, with the rotating end connected to the third bearing end cap 2.35 and the stationary end connected to the center hole of the third bearing end cap 2.35; finally, press the outer ring of the fourth deep groove ball bearing 2.32 with the third bearing end cap 2.35 and fix it to the C-axis bearing seat 2.33; insert the third vacuum hose 2.36 into the center hole of the third bearing end cap 2.35 and connect it to the third low-temperature resistant rotary dynamic seal joint 2.34 via a threaded connection;

[0012] When the cryogenic medium internal spray type double oscillating head electric spindle rotates in the drawbar state and internally sprays cryogenic medium, the cryogenic medium flows out from the external source and passes sequentially through the third vacuum hose 2.36, the third cryogenic resistant rotary dynamic seal joint 2.34, the third vacuum mandrel 2.25, the second vacuum hose 2.23, the A-axis rear end cover 2.21, the second cryogenic resistant rotary dynamic seal joint 2.19, the second vacuum mandrel 2.13, the first vacuum hose 2.11, and the first cryogenic resistant rotary dynamic seal joint 1.24; finally, it enters the cryogenic medium internal spray type electric spindle 2.8, and then passes through the vacuum partition drawbar 1.23 and the hollow tool holder 1.29, and is ejected from the end of the internally cooled tool 1.32, ready for machining to begin.

[0013] The beneficial effects of this invention are: through the independent design of the cryogenic medium internal spray type double-swivel head electric spindle, a cooling method is achieved by delivering the cryogenic medium to the tool tip through the internal cavity channel of the double-swivel head-electric spindle-tool; the cryogenic medium delivery pipeline inside the double-swivel head electric spindle adopts a vacuum insulation structure, successfully isolating the potential performance damage of the double-swivel head and electric spindle to extreme low temperatures; in the internal structure of the double-swivel head electric spindle, the dynamic and static mating surfaces are connected by a low-temperature resistant rotary dynamic seal joint, ensuring good dynamic sealing while also taking into account the multi-axis linkage motion function of the double-swivel head electric spindle; the cryogenic medium delivery pipeline passes through the center of the swivel head and electric spindle, achieving reliable medium transmission without affecting the original structural compactness and motion freedom; the electric spindle adopts a vacuum-insulated tie rod, which not only realizes automatic tool changing but also provides heat insulation. Attached Figure Description

[0014] Figure 1 A schematic diagram of a cryogenic medium internal spray type double swing head electric spindle structure;

[0015] Figure 2 This is a schematic diagram of a cryogenic medium internal spray electric spindle.

[0016] In the diagram: 1.1 - Spindle core; 1.2 - Front bearing housing; 1.3 - First angular contact bearing; 1.4 - First bushing; 1.5 - Second angular contact bearing; 1.6 - Second bushing; 1.7 - Third angular contact bearing; 1.8 - Third bushing; 1.9 - First bearing cap; 1.10 - Second bearing cap; 1.11 - First motor housing; 1.12 - Spindle motor stator; 1.13 - Spindle motor rotor; 1.14 - Rear bearing housing; 1.15 - Fourth bushing; 1.16 - Fourth angular contact bearing; 1.17 - Fifth bushing; 1.18 - Fifth angular contact bearing; 1.19 - Third... 1.20 - Bearing cap; 1.21 - Rear end cap; 1.22 - Tool clamping cylinder; 1.23 - Tool puller disc spring; 1.24 - Vacuum partition tool puller rod; 1.25 - First low-temperature resistant rotary dynamic seal joint; 1.26 - End plug; 1.27 - Connecting pipe; 1.28 - Puller claw; 1.29 - Heat insulation sleeve; 1.30 - Hollow tool holder; 1.31 - Spring collet; 1.32 - Locking nut; 1.33 - Internally cooled tool; 2.1 - First vacuum mandrel; 2.2 - First deep groove ball bearing; 2.3 - First bearing end cap; 2.4 - First A-axis torque motor rotor; 2.5 - First A-axis torque motor stator; 2.6 - 2.7-First encoder; 2.8-Cryogenic medium internal injection electric spindle; 2.9-Spindle box; 2.10-Housing housing; 2.11-First vacuum hose; 2.12-First copper connector; 2.13-Second vacuum spindle; 2.14-Second deep groove ball bearing; 2.15-Second bearing end cover; 2.16-Second A-axis torque motor stator; 2.17-Second A-axis torque motor rotor; 2.18-Third motor base; 2.19-Second cryogenic rotary dynamic seal joint; 2.20-Second encoder; 2.21-A-axis rear end cover; 2.22-Protective plate; 2.23-Second... Vacuum hose; 2.24-Second copper connector; 2.25-Third vacuum mandrel; 2.26-Third deep groove ball bearing; 2.27-Transition disc; 2.28-C-axis torque motor rotor; 2.29-C-axis torque motor stator; 2.30-Fourth motor mount; 2.31-Upper end cover; 2.32-Fourth deep groove ball bearing; 2.33-C-axis bearing mount; 2.34-Third low-temperature resistant rotary dynamic seal joint; 2.35-Third bearing end cover; 2.36-Third vacuum hose; 2.a-Transition disc groove surface; 2.b-Upper side plane of the housing; 2.c-Upper side cylindrical surface of the housing; 2.d-A-Rear end cap hole of the shaft. Detailed Implementation

[0017] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings and technical solutions.

[0018] In this embodiment, the cryogenic medium is liquid nitrogen, with a minimum temperature of -196℃; the cryogenic medium internal spray electric spindle 1.8 is HSK-A63, with a maximum speed of 21000rpm, a power of 35kW, and a torque of 80Nm; the vacuum partition broach 2.10 has a diameter of 50mm and a thermal conductivity of approximately 0; the heat insulation sleeve 2.5 is made of modified polyimide with a thermal conductivity of less than 0.15W / (m·K); the rotating and stationary end faces of the first cryogenic rotary dynamic seal joint 2.30, the second cryogenic rotary dynamic seal joint 1.19, and the third cryogenic rotary dynamic seal joint 1.34 are made of ceramic, with a spring stiffness coefficient of 10N / m; the A / C axis rotation range is ±110° / ±360°, the positioning accuracy is 6″, and the repeatability is 5″.

[0019] The assembly process of the cryogenic medium internal spray type double-swivel electric spindle is as follows: (see attached) Figure 1 , 2As shown, in the first step, the first angular contact bearing 1.3 is assembled between the main spindle core 1.1 and the front bearing housing 1.2 with a transition fit; then, the first bushing 1.4 is pushed in along the main spindle core 1.1 until it abuts against the inner ring of the first angular contact bearing 1.3; then, the second angular contact bearing 1.5, the second bushing 1.6, the third angular contact bearing 1.7, and the third bushing 1.8 are pushed in sequentially along the front end of the main spindle core 1.1 until they abut against the first bushing 1.4. The inner rings of the third angular contact bearing 1.7 and the second angular contact bearing 1.5 are both transition fits with the main spindle core 1.1, and their outer rings are transition fits with the front bearing housing 1.2; the outer ring of the third angular contact bearing 1.7 is then pressed using the first bearing press. Tighten cover 1.9, and press the third bushing 1.8 with the second bearing cover 1.10, thereby indirectly locking the inner ring of the third angular contact bearing 1.7; then install the spindle motor rotor 1.13 onto the spindle core 1.1; then install the spindle motor stator 1.12 onto the first motor mount 1.11, and connect the first motor mount 1.11 to the front bearing seat 1.2 with bolts; then fix the rear bearing seat 1.14 to the first motor mount 1.11 with bolts; then sequentially install the fourth bushing 1.15, the fourth angular contact bearing 1.16, the fifth bushing 1.17, and the fifth angular contact bearing 1.18 along the rear end of the spindle core 1.1, where the fourth angular contact bearing 1.17 is the first angular contact bearing 1.18. The inner rings of bearings 1.16 and 1.18 are transition-fitted with the spindle core 1.1, and the outer rings are transition-fitted with the rear bearing housing 1.14. The inner ring of the 1.18 is then locked in place using the third bearing cap 1.19. The rear end cap 1.20 is then bolted to the rear bearing housing 1.14. The broaching disc spring 1.22 is mounted on the vacuum-insulated broaching rod 1.23, which is then inserted into the spindle core 1.1. The tool-changing cylinder 1.21 is then bolted onto the rear end cap 1.20. One end of the vacuum-insulated broaching rod 1.23 is connected to the broaching claw 1.27, and the other end is connected via a first low-temperature resistant rotary valve. The sealing connector 1.24 is connected to the end plug 1.25 via a threaded connection. The end plug 1.25 is then connected to the first vacuum hose 2.11 via the connecting pipe 1.26. Next, the heat insulation sleeve 1.28 is connected to the hollow tool holder 1.29 via a threaded connection. The spring collet 1.30 is then inserted into the hollow tool holder 1.29, and the internal cooling tool 1.32 is inserted into the spring collet 1.30 until it abuts against the heat insulation sleeve 1.28, and then locked with the locking nut 1.31. The hollow tool holder 1.29 is then installed into the spindle core 1.1. Finally, the cryogenic dielectric electric spindle 2.8 is fixed to the spindle box 2.10 via bolts. This completes the assembly of the cryogenic dielectric electric spindle 1.8.

[0020] The second step involves fixing the first vacuum spindle 2.1 to the spindle box 2.9 with bolts; connecting the first vacuum spindle 2.1 to the housing 2.10 via the first deep groove ball bearing 2.2, wherein the inner ring of the bearing has a transition fit with the first vacuum spindle 2.1, and the outer ring of the bearing has a transition fit with the housing 2.10; pressing the outer ring of the first deep groove ball bearing 2.2 with the first bearing end cap 2.3; fixing the first A-axis torque motor stator 2.5 onto the second motor mount 2.6, and fastening the second motor mount 2.6 to the housing 2.10; fixing the first A-axis torque motor rotor 2.4 onto the first vacuum spindle 2.1, wherein the first A-axis torque motor stator 2.5 and the A-axis torque motor rotor 2.4 have a clearance fit; and connecting the first encoder 2.7 to the second motor mount 2.6. This completes the assembly of the first cryogenic medium internal spray type A-axis oscillating head.

[0021] Thirdly, the second vacuum spindle 2.13 is fixedly connected to the spindle box 2.9 with bolts, allowing the spindle box 2.9 to rotate around the A-axis; the second vacuum spindle 2.13 is connected to the first vacuum hose 2.11 via a first copper connector 2.12 using a threaded connection; the second vacuum spindle 2.13 is connected to the housing 2.10 via a second deep groove ball bearing 2.14, wherein the inner ring of the bearing has a transition fit with the second vacuum spindle 2.13, and the outer ring of the bearing has a transition fit with the housing 2.10; the second bearing end cap 2.15 is pressed against the outer ring of the second deep groove ball bearing 2.14; the second A-axis torque motor stator 2.16 is fixed on the third motor mount 2.18, and the third motor mount 2.18 is fastened to the housing 2.10; the second A-axis... The torque motor rotor 2.17 is fixed on the second vacuum spindle 2.13, wherein the second A-axis torque motor stator 2.16 and the second A-axis torque motor rotor 2.17 are in clearance fit, and the second encoder 2.20 is connected to the third motor base 2.18; the second cryogenic rotary dynamic seal joint 2.19 is connected to the second vacuum spindle 2.13 by means of threads, with the rotating end connected to the second vacuum spindle 2.13 and the stationary end connected to the center hole of the A-axis rear end cover 2.21; the A-axis rear end cover 2.21 is fixed to the third motor base 2.18, and the second vacuum hose 2.23 is inserted into the hole 2.d of the A-axis rear end cover and connected to the stationary end of the second cryogenic rotary dynamic seal joint 2.19 by means of threads; thus, the assembly of the second cryogenic medium internal spray type A-axis swing head is completed;

[0022] Fourth step: Install the third deep groove ball bearing 2.26 onto the upper cylindrical surface 2.c of the housing 2.10 with an transition fit; connect one end of the second copper connector 2.24 to the second vacuum hose 2.23 with a thread, and the other end to the third vacuum mandrel 2.25; fix the bottom of the third vacuum mandrel 2.25 to the upper plane 2.b of the housing 2.10 with bolts, while simultaneously pressing the inner ring of the third deep groove ball bearing 2.26; then pass the protective plate 2.22 through... The C-axis torque motor stator 2.29 is then fixed to the fourth motor mount 2.30 via bolts. The fourth motor mount 2.30 is then connected and fixed to the transition plate 2.27. The transition plate 2.27 is pushed into the outer ring of the third deep groove ball bearing 2.26 with a transition fit until the groove surface 2.a of the transition plate presses against the outer ring of the third deep groove ball bearing 2.26. At this point, the third vacuum spindle 2.25 and the center hole of the transition plate 2.27 are aligned. Clearance fit; mount the C-axis torque motor rotor 2.28 onto the third vacuum spindle 2.25, then fix the upper end cover 2.31 to the upper side of the fourth motor mount 2.30 with bolts; push the C-axis bearing seat 2.33 into the center hole of the upper end cover 2.31 and fix it to the upper end cover 2.31 with bolts; assemble the fourth deep groove ball bearing 2.32 between the C-axis bearing seat 2.33 and the third vacuum spindle 2.25 with an transition fit; install the third low-temperature resistant rotary dynamic seal joint 2... .34 The rotating end is connected to the third vacuum mandrel 2.25 via a thread, and the stationary end is connected to the center hole of the third bearing end cap 2.35; finally, the outer ring of the fourth deep groove ball bearing 2.32 is pressed down by the third bearing end cap 2.35 and fixed to the C-axis bearing seat 2.33; the third vacuum hose 2.36 is inserted into the center hole of the third bearing end cap 2.35 and connected to the third low-temperature resistant rotary dynamic seal joint 2.34 via a thread; thus, the assembly of the cryogenic medium internal spray type C-axis swing head is completed;

[0023] When the cryogenic medium internal spray type double oscillating head electric spindle is running in the drawbar state and internally spraying liquid nitrogen, the liquid nitrogen flows out from the external source and passes sequentially through the third vacuum hose 2.36, the third cryogenic resistant rotary dynamic seal joint 2.34, the third vacuum mandrel 2.25, the second vacuum hose 2.23, the A-axis rear end cover 2.21, the second cryogenic resistant rotary dynamic seal joint 2.19, the second vacuum mandrel 2.13, the first vacuum hose 2.11, and the first cryogenic resistant rotary dynamic seal joint 1.24; finally, it enters the cryogenic medium internal spray type electric spindle 2.8, and then passes through the vacuum partition drawbar 1.23 and the hollow tool holder 1.29, and is ejected from the end of the internally cooled tool 1.32. The flow rate is about 30 to 50 L / h, and the temperature is about -196 to -180℃, at which point machining can begin.

[0024] This invention employs a cooling approach where cryogenic medium is delivered to the tool tip via an internal channel connecting the dual-swivel head, electric spindle, and cutting tool, achieving point-to-point cooling of the cryogenic medium during dual-swivel head electric spindle cutting. The rational use of cryogenic rotary dynamic seal joints and cryogenic medium vacuum transmission pipelines ensures thermal insulation and sealing during cryogenic medium transmission. Core functional components for high-end cryogenic machining equipment are designed to facilitate the smooth implementation of high-speed cryogenic machining of complex curved surface components.

[0025] Obviously, the embodiments described above are only some, not all, of the embodiments in this application. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort should fall within the scope of protection of this application. In summary, the content of this specification should not be construed as a limitation of this application.

Claims

1. A cryogenic medium internal spray type double-swivel head electric spindle, characterized in that, The cryogenic medium internal spray type double-swivel electric spindle mainly consists of a cryogenic medium internal spray type electric spindle (2.8), a cryogenic medium internal spray type A-axis swivel head section, and a cryogenic medium internal spray type C-axis swivel head section. The cryogenic medium internal spray type A-axis swivel head section includes a first cryogenic medium internal spray type A-axis swivel head section and a second cryogenic medium internal spray type A-axis swivel head section respectively arranged on the left and right sides. The first cryogenic medium internal spray type A-axis swivel head section includes a first vacuum spindle (2.1), a first deep groove ball bearing (2.2), a first bearing end cover (2.3), a first A-axis torque motor rotor (2.4), a first A-axis torque motor stator (2.5), a second motor base (2.6), a first encoder (2.7), and a spindle box (2.9). The second cryogenic medium internal spray type A-axis swivel head section includes a second vacuum spindle (2.13) and a second deep groove ball bearing. The components include: bearing (2.14), second bearing end cover (2.15), second A-axis torque motor stator (2.16), second A-axis torque motor rotor (2.17), third motor mount (2.18), second low-temperature resistant rotary dynamic seal joint (2.19), second encoder (2.20), and A-axis rear end cover (2.21); the cryogenic medium internal spray type C-axis swing head includes: housing (2.10), third vacuum spindle (2.25), third deep groove ball bearing (2.26), transition plate (2.27), C-axis torque motor rotor (2.28), C-axis torque motor stator (2.29), fourth motor mount (2.30), upper end cover (2.31), fourth deep groove ball bearing (2.32), C-axis bearing seat (2.33), third low-temperature resistant rotary dynamic seal joint (2.34), and third bearing end cover (2.35); Assembling of the cryogenic medium internal injection electric spindle (2.8): The first angular contact bearing (1.3) is assembled between the spindle core (1.1) and the front bearing housing (1.2) with a transition fit; the first bushing (1.4) is pushed in along the spindle core (1.1) until it abuts against the inner ring of the first angular contact bearing (1.3); the second angular contact bearing (1.5), the second bushing (1.6), the third angular contact bearing (1.7), and the third bushing (1.8) are pushed in sequence along the front end of the spindle core (1.1) until they abut against the first bushing (1.4), wherein the inner rings of the third angular contact bearing (1.7) and the second angular contact bearing (1.5) are both transition fits with the spindle core (1.1), and the inner rings of the third angular contact bearing (1.7) and the second angular contact bearing (1.8) are... 1.5) The outer ring of the bearing is transition-fitted with the front bearing housing (1.2); the outer ring of the third angular contact bearing (1.7) is locked with the first bearing cap (1.9), and the third bushing (1.8) is pressed with the second bearing cap (1.10), thereby indirectly locking the inner ring of the third angular contact bearing (1.7); the spindle motor rotor (1.13) is mounted on the spindle core (1.1); the spindle motor stator 1.12 is mounted on the first motor housing (1.11), and the first motor housing (1.11) is connected to the front bearing housing (1.2) by bolts; the rear bearing housing (1.14) is fixed to the first motor housing (1.11) by bolts; the fourth bushing (1.15) is installed sequentially along the rear end of the spindle core (1.1). The system comprises a fourth angular contact bearing (1.16), a fifth bushing (1.17), and a fifth angular contact bearing (1.18). The inner rings of the fourth angular contact bearing (1.16) and the fifth angular contact bearing (1.18) are fitted with the spindle core (1.1), and their outer rings are fitted with the rear bearing housing (1.14). The inner ring of the fifth angular contact bearing (1.18) is locked in place by a third bearing cap (1.19). The rear end cap (1.20) is connected to the rear bearing housing (1.14) by bolts. The broaching disc spring (1.22) is installed on the vacuum spacer broaching rod (1.23), and the vacuum spacer broaching rod (1.23) is inserted into the spindle core (1.1). Then, the tool-changing cylinder (1.21) is installed using bolts. On the rear end cover (1.20); one end of the vacuum partition puller rod (1.23) is connected to the pull claw (1.27), and the other end is connected to the end plug (1.25) through the first low-temperature resistant rotary dynamic sealing joint (1.24), with the connection being a threaded connection; the end plug (1.25) is connected to the first vacuum hose (2.11) through the connecting pipe (1.26); the heat insulation sleeve (1.28) is connected to the hollow tool holder (1.29) through a threaded connection, then the spring collet (1.30) is placed into the hollow tool holder (1.29), and the internal cooling tool (1.32) is inserted into the spring collet (1.30) until it abuts against the heat insulation sleeve (1.28), and locked with the locking nut (1.31); the hollow tool holder (1.29) is installed into the spindle core (1).1) The cryogenic dielectric electric spindle (2.8) is fixed to the spindle box (2.9) by bolt connection; Assembly of the first cryogenic medium internal spray type A-axis oscillating head: The first vacuum mandrel (2.1) is fixedly connected to the spindle box (2.9) with bolts; the first vacuum mandrel (2.1) is connected to the housing (2.10) via a first deep groove ball bearing (2.2), wherein the inner ring of the bearing has a transition fit with the first vacuum mandrel (2.1), and the outer ring of the first deep groove ball bearing (2.2) has a transition fit with the housing (2.10); the first bearing end cap (2.3) is pressed tightly against the first deep groove ball bearing. The outer ring of the groove ball bearing (2.2); the stator (2.5) of the first A-axis torque motor is fixed on the second motor mount (2.6), and the second motor mount (2.6) is fastened to the housing (2.10); the rotor (2.4) of the first A-axis torque motor is fixed on the first vacuum spindle (2.1), wherein the stator (2.5) of the first A-axis torque motor and the rotor 2.4 of the A-axis torque motor are in clearance fit, and the first encoder (2.7) is connected to the second motor mount (2.6); Assembly of the second cryogenic medium internal spray type A-axis oscillating head: The second vacuum spindle (2.13) is fixedly connected to the main spindle box (2.9) by bolts, so that the main spindle box (2.9) can rotate around the A-axis; the second vacuum spindle (2.13) and the first vacuum hose (2.11) are connected by a threaded connection through the first copper connector (2.12); the second vacuum spindle (2.13) is connected to the housing (2.10) through the second deep groove ball bearing (2.14), wherein the inner ring of the bearing is in transition fit with the second vacuum spindle (2.13), and the outer ring of the bearing is in transition fit with the housing (2.10); the second bearing end cover (2.15) is pressed against the outer ring of the second deep groove ball bearing (2.14); the second A-axis torque motor stator (2.16) is fixed on the third motor base (2.18), and the third motor base... (2.18) Secure it to the housing (2.10); fix the second A-axis torque motor rotor (2.17) on the second vacuum spindle (2.13), wherein the second A-axis torque motor stator (2.16) and the second A-axis torque motor rotor (2.17) are in clearance fit, and the second encoder (2.20) is connected to the third motor base (2.18); connect the second low-temperature resistant rotary dynamic seal joint (2.19) to the second vacuum spindle (2.13) through a threaded connection, and connect the stationary end to the center hole of the A-axis rear end cover (2.21); fix the A-axis rear end cover (2.21) to the third motor base (2.18), and insert the second vacuum hose (2.23) into the hole (2.d) of the A-axis rear end cover, and connect it to the stationary end of the second low-temperature resistant rotary dynamic seal joint (2.19) through a threaded connection; Assembly of the C-axis swing head with internal spray for cryogenic medium: The third deep groove ball bearing (2.26) is installed onto the upper cylindrical surface (2.c) of the housing (2.10) with an intermediate fit; one end of the second copper connector (2.24) is threaded to the second vacuum hose (2.23), and the other end is connected to the third vacuum mandrel (2.25); the bottom of the third vacuum mandrel (2.25) is bolted to the upper plane (2.b) of the housing (2.10), while simultaneously tightening the third deep groove ball bearing (2.26). The inner ring; the protective plate (2.22) is fixed to the housing (2.10) by bolt connection; the C-axis torque motor stator (2.29) is fixed to the fourth motor base (2.30) by bolt connection; the fourth motor base (2.30) is connected and fixed to the transition plate (2.27); the transition plate (2.27) is pushed into the outer ring of the third deep groove ball bearing (2.26) in a transition fit until the groove surface (2.a) of the transition plate presses against the outer ring of the third deep groove ball bearing (2.26), at which point the third vacuum mandrel (2.2) 5) The C-axis torque motor rotor (2.28) is fitted with the center hole of the transition plate (2.27) with clearance; the C-axis torque motor rotor (2.28) is mounted on the third vacuum mandrel (2.25), and then the upper end cover (2.31) is fixed to the upper side of the fourth motor base (2.30) by bolt connection; the C-axis bearing housing (2.33) is pushed into the center hole of the upper end cover (2.31) and fixed to the upper end cover (2.31) by bolt connection; the fourth deep groove ball bearing (2.32) is assembled with the C-axis bearing housing (2.33) and the third vacuum mandrel (2.25) with transition fit. Between 25); the third low-temperature resistant rotary dynamic seal joint (2.34) is connected to the third vacuum mandrel (2.25) by means of a thread, and the stationary end is connected to the center hole of the third bearing end cap (2.35); finally, the third bearing end cap (2.35) is used to press the outer ring of the fourth deep groove ball bearing (2.32) and fix it to the C-axis bearing seat (2.33); the third vacuum hose (2.36) is inserted into the center hole of the third bearing end cap (2.35) and connected to the third low-temperature resistant rotary dynamic seal joint (2.34) by means of a thread.

2. The cryogenic medium internal spray type double-swivel head electric spindle according to claim 1, characterized in that, When the cryogenic medium internal spray type double oscillating head electric spindle rotates in the drawbar state and internally sprays cryogenic medium, the cryogenic medium flows out from the external source and passes sequentially through the third vacuum hose (2.36), the third cryogenic resistant rotary dynamic seal joint (2.34), the third vacuum mandrel (2.25), the second vacuum hose (2.23), the A-axis rear end cover (2.21), the second cryogenic resistant rotary dynamic seal joint (2.19), the second vacuum mandrel (2.13), the first vacuum hose (2.11), and the first cryogenic resistant rotary dynamic seal joint (1.24); finally, it enters the cryogenic medium internal spray type electric spindle (2.8), and then passes through the vacuum partition drawbar (1.23) and the hollow tool holder (1.29), and is ejected from the end of the internally cooled tool (1.32), so that machining can begin.

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