An operating space-enclosed ultra-low temperature cooling lathe

Abstract

The application belongs to the technical field of sealing component design, and discloses an operating space closed ultra-low temperature cooling lathe, which comprises an inclined bed lathe main machine, an ultra-low temperature medium heat insulation transmission control system, a closed protective cabin, a temperature active control system, a vacuum adsorption main shaft and an ultra-low temperature medium internal spraying tool turret. The structure design of the inclined bed lathe main machine and the closed protective cabin is optimized, the efficient sealing property of the closed space is ensured, and the controllability of the water and oxygen content in the processing area atmosphere is realized. The temperature active control system improves the low-temperature deformation problem of the lathe main body structure caused by the introduction of the ultra-low temperature medium. The ultra-low temperature medium internal spraying tool turret is innovatively proposed, the directional supply of the ultra-low temperature medium to the working lathe tool during automatic tool changing is realized, and the integration difficulty of the ultra-low temperature medium internal spraying cooling function and the conventional lathe function is solved. The ultra-low temperature medium heat insulation transmission control system is integrally integrated with the numerical control lathe, and the stable controllability of the pressure and flow during the ultra-low temperature medium transmission process is realized.

Description

Technical Field

[0001] This invention belongs to the field of CNC machine tool design technology, and relates to a closed-space ultra-low temperature cooling lathe. Background Technology

[0002] In specialized fields such as aerospace, special material shell and cylindrical parts, due to their high chemical reactivity and low ignition point, are prone to combustion and surface oxidation corrosion during conventional cooling and cutting. This results in poor part quality, low efficiency, and the generation of highly radioactive aerosols, seriously endangering operator safety. By using an inert atmosphere to protect the turning area, purifying the atmosphere of water and oxygen, and achieving complete sealing, while employing ultra-low temperature cooling media such as liquid nitrogen for intense cooling of the cutting area, the machining challenges of combustion and surface oxidation corrosion can be effectively solved, thereby ensuring part quality and operator health and safety.

[0003] Clearly, the closed-space cryogenic cooling lathe is a crucial piece of equipment for achieving anhydrous and oxygen-free cryogenic turning of highly reactive special material parts. However, achieving the filling and complete sealing of the machining area with an inert atmosphere, and the effective integration of cryogenic cooling functionality with the lathe structure, while ensuring the conventional functions of the CNC lathe do not affect its stable operation, is extremely challenging. For example, how to construct an independent, sealed machining space within a highly integrated lathe system and ensure its excellent sealing performance; how to actively control the temperature field of the lathe's main machine tool within a sealed space with a continuous liquid nitrogen jet to prevent the overall machining accuracy from deteriorating due to low-temperature deformation of critical components; how to integrate a cryogenic cooling medium insulation, transmission, and control system within the limited internal space of the lathe, enabling it to regulate flow and pressure; and how to ensure the directional supply of cryogenic cooling medium to the working tool while maintaining automatic tool changing functionality. Therefore, a rational design for the closed-space cryogenic cooling lathe is essential.

[0004] Currently, several structural designs for enclosed lathes and cryogenic cooling lathes have been invented by domestic and international institutions. In 2020, Li Jijun of the Institute of Materials Science and Engineering, China Academy of Engineering Physics, published an article entitled "A Dedicated Machining Glove Box for Horizontal CNC Lathes and an Automatic Atmosphere Control Method" in Volume 69, Issue 11 of "Manufacturing Technology & Machine Tool". The article describes a dedicated machining glove box structure for horizontal CNC lathes. The glove box with a special structure seals the machining area, and the automatic atmosphere control system realizes automatic gas replacement in the glove box. However, this machine tool can only perform dry cutting, and still has problems such as excessively high cutting temperature and difficulty in chip breakage. In 2024, Dalian University of Technology disclosed "a CNC lathe with cryogenic medium internal spray cooling via turret-tool" in invention patent 202411613330.8. The invention sets up an axial transmission channel inside the turret and a transmission distribution block on the top of the tool head to transmit cryogenic medium to the working tool. However, the cryogenic medium transmission channel is set up inside the turret, which places high demands on the sealing performance. Once a leak occurs, the moving structure of the turret will freeze and malfunction. In addition, the machine tool does not have a sealing function. In 2012, MAG Industrial Automation Systems Co., Ltd. disclosed a "tool turret for machining workpieces and a machining system having such a tool turret" in invention patent 201280006086.8. The tool turret has a cryogenic medium delivery pipeline designed inside the side of the turret, and a delivery channel is machined inside the cutting tool and its mounting tool holder to provide cryogenic medium to the working cutting tool. However, the cryogenic medium of this machine tool is directly supplied by a thermal insulation storage device, which does not have the function of flow and pressure regulation, and cannot guarantee the stability and controllability of the cryogenic medium jet. At the same time, it cannot achieve the function of sealing. Summary of the Invention

[0005] This invention addresses the shortcomings or improvement needs of existing technologies by proposing a closed-loop cryogenic cooling lathe that overcomes challenges such as the closed-loop regulation of gas components in the machining area, the active control of thermal deformation of the machine tool caused by continuous liquid nitrogen jets in the closed space, the directional supply of cryogenic cooling medium to the working tool during automatic tool changing in the servo turret, and the heat insulation and controllable transmission of the cryogenic cooling medium.

[0006] The technical solution of the present invention: A closed-loop cryogenic cooling lathe mainly consists of a slant bed lathe main unit, a cryogenic medium heat insulation and transmission control system, a sealed protective chamber, a temperature active control system, a vacuum adsorption spindle, and a cryogenic medium internal spray turret. The cryogenic medium internal spray turret is mounted on the turret seat 1 of the slant bed lathe main unit and is used to clamp the tool and spray the cryogenic medium into the cutting zone. The vacuum adsorption spindle 2 is mounted on the spindle seat 4 on the bed 3 of the slant bed lathe main unit. The spindle 2 and the spindle guard plate 5 are sealed by a first sealing ring 6. Driven by the main spindle motor 7 and belt assembly 8; the cryogenic medium thermal insulation transmission control system is connected to the transmission block 11 of the cryogenic medium internal spray turret through the first vacuum hose 9 and the first copper connector 10; the sealed protective chamber 12 of the sealed protective chamber is installed on the upper surface 14 of the bed through the flange mating edge 13. The flange mating edge 13 is provided with a first sealing ring groove 15, and the first sealing strip 16 is provided in the first sealing ring groove 15. When the flange mating edge 13 is connected to the bed 3, the first sealing strip 16 is pressed to achieve the sealing isolation between the sealed protective chamber and the bed 3.

[0007] The structure of the slant bed lathe main unit is as follows: the second sealing strip 17 is installed in the second sealing ring groove 18 on the bed 3, and the spindle guard plate 5 is fixed to the bed 3 by the first bolt 19 and the second sealing strip 17 is pressed tightly; the spindle seat 4 is fixed on the spindle seat mounting surface 20 of the bed 3; two Z-axis guide rails 21 are fixed on the Z-axis guide rail mounting surface 22 of the bed 3; four Z-axis sliders 23 are installed on the lower surface 25 of the slide saddle 24, and the Z-axis sliders 23 slide with the Z-axis guide rails 21, and the power comes from the transmission of the Z-axis motor 26 and the Z-axis lead screw 27; two X-axis guide rails 29 are fixed on the upper surface 28 of the slide saddle, and four X-axis sliders 30 are installed on the lower surface 31 of the turret seat, and the X-axis sliders 30 slide with the X-axis guide rails 29, and the power comes from the transmission of the X-axis motor 32 and the X-axis lead screw 33; the chip receiving tray 34 is placed in the chip receiving groove 35 on the bed 3 for recycling chips.

[0008] The structure of the cryogenic medium thermal insulation transmission control system is as follows: the outlet valve 37 on the self-pressurized liquid nitrogen tank 36 is connected to the second vacuum hose 39 via the first nut 38, and the second vacuum hose 39 is connected to one end of the stainless steel rigid tube 41 via the second nut 40; the stainless steel rigid tube 41 is sequentially connected to a pressure reducing valve 42, a flow meter 43, a safety valve 44, a regulating valve 45, a temperature sensor 46, and a pressure sensor 47, and the stainless steel rigid tube 41 is wrapped with a polyurethane foam layer 48; the other end of the stainless steel rigid tube 41 is connected to one end of the vacuum rigid tube 50 via the third nut 49, and the other end of the vacuum rigid tube 50 is connected to the first vacuum hose 9 via the fourth nut 51; the vacuum rigid tube 50 and the main shaft protective plate 5 are sealed by a second sealing ring 52; the stainless steel rigid tube 41 is fixed to the control unit box 54 by several fastening hoops 53; the valve actuator 55 of the regulating valve 45 is reinforced to the control unit box 54 by a bracket 56, and the data acquisition and transmission module 57 is fixed to the control unit box 54.

[0009] The structure of the sealed protective chamber is as follows: two quick-lift doors 58 are installed on the front side of the sealed protective chamber 12 via hinges; the two ends of the gas spring bracket 59 are fixed to the first interface 60 on the sealed protective chamber 12 and the second interface 61 on the quick-lift doors 58, respectively; several locking buckles 62 are installed on the quick-lift doors 58; the transition chamber 63 is installed on the right side of the sealed protective chamber 12 via a flange; the exhaust pipe 64 and the gas transmission pipe 65 are fixed to the rear side of the sealed protective chamber 12; and the water analyzer 66, oxygen analyzer 67, and nitrogen analyzer 68 are installed on the top of the sealed protective chamber 12.

[0010] The structure of the active temperature control system is as follows: the heating block 69 is fixed to the inner surface of the top of the sealed protective chamber 12, the protective shell 70 covers the outside of the heating block 69 and is fixed to the sealed protective chamber 12 by the second bolt 71; the circulating fan 72 is installed at the bottom of the protective shell 70; the conversion connector 73 is installed at the inlet 75 and outlet 76 of the temperature control channel 74 inside the bed 3 for connection with the conveying pipeline of the temperature control medium.

[0011] The structure of the vacuum adsorption spindle is as follows: a three-jaw chuck 77 is fixed to the nose end of the spindle 2; a vacuum pull rod 78 is pushed into the hollow channel 80 of the spindle 2 through the through hole 79 on the three-jaw chuck 77; a connecting female head 81 is fixed to the head end of the vacuum pull rod 78; and a rotary joint 82 is installed to the tail end of the vacuum pull rod 78 for connection with the transmission pipeline of the vacuum source.

[0012] The structure of the cryogenic medium internal spray turret is as follows: the transmission block 11 is fixedly connected to the turret housing 83; the directional plate 84 is fixed to the cutter head 86 by the third bolt 85; the outer turning tool bar 87 is inserted into the tool slot 88 on the cutter head 86, the wedge-shaped clamping block 89 is pushed into the tool slot 88 on the cutter head 86, and the wedge-shaped clamping block 89 is fastened to the cutter head 86 by the fourth bolt 90; the tool holder 91 is fixedly connected to the cutter head 86; the boring tool bar 92 is pushed into the tool holder 91 and pressed by the fifth bolt 93; one end of the first liquid nitrogen transmission hose 94 is connected to the directional plate 84 through the second copper connector 95, and the other end is connected to the jet head 97 on the outer turning tool bar 87 through the third copper connector 96; one end of the second liquid nitrogen transmission hose 98 is connected to the directional plate 84 through the fourth copper connector 99, and the other end is connected to the tail end of the boring tool bar 92 through the fifth copper connector 100.

[0013] When the workpiece is clamped on the closed-space cryogenic cooling lathe, the male connector 102 on the vacuum adsorption fixture 101 is first paired with the female connector 81; then the three-jaw chuck 77 is used to clamp the straight connector 103 of the vacuum adsorption fixture 101. The spherical workpiece 104 and the vacuum adsorption fixture 101 together form a closed vacuum adsorption cavity 105, thereby using the adsorption force generated by the vacuum negative pressure to achieve stable clamping of the spherical workpiece 104.

[0014] When the cryogenic cooling lathe with a sealed operating space is used for cryogenic cooling processing, first open the transition chamber door 106 of the transition chamber 63, transport the workpiece to be processed to the sealed protective chamber 12, and close the transition chamber door 106; clamp the workpiece to be processed to the three-jaw chuck 77 through the glove opening 107; connect the nitrogen source to the gas supply pipe 65 and the exhaust pipe 64 to the workshop exhaust, to replace the moisture and oxygen in the sealed protective chamber 12; then the cryogenic medium flows out from the self-pressurized liquid nitrogen tank 36, and passes sequentially through the second vacuum hose 39, the stainless steel rigid pipe 41, the vacuum rigid pipe 50, the first vacuum hose 9, and the internal flow channel 108 of the transfer block 11. The first flow channel 109 inside the first direction selector plate 84 and the first liquid nitrogen transfer hose 94 are finally ejected from the first jet port 110 at the front end of the jet head 97 for ultra-low temperature cooling processing. During the ultra-low temperature cooling processing, the heating function of the heating block 69 is turned on, and the hot and cold gases in the sealed protective chamber 12 are mixed by the circulating fan 72 to improve the low temperature deformation of the machine tool caused by the continuous jet of ultra-low temperature medium. After the ultra-low temperature cooling processing is completed, the processed workpiece and the chip receiving plate 34 are transferred to the outside of the sealed protective chamber 12 through the transition chamber 63. Then, the processed chips in the chip receiving plate 34 are treated in accordance with regulations to complete the ultra-low temperature cooling processing.

[0015] When the closed-space cryogenic cooling lathe automatically changes tools, when it automatically switches from the external turning tool holder 87 to the boring tool holder 92, the tool head 86 moves axially away from the turret housing 83, interrupting the flow channel 108 inside the transmission block 11 and the first flow channel 109 inside the direction selector plate 84. After the tool head 86 rotates a certain angle, it moves axially towards the turret housing 83, connecting the flow channel 108 inside the transmission block 11 with the second flow channel 111 inside the direction selector plate 84. After that, the cryogenic medium can pass through the second liquid nitrogen transmission hose 98 and the flow channel 112 inside the boring tool holder 92, and finally be ejected from the second jet port 113 at the front end of the boring tool holder 92, completing the directional supply of cryogenic medium to the working tool that also has the function of automatic tool changing.

[0016] The beneficial effects of this invention are as follows: by optimizing the structural design of the slant bed lathe main unit and the sealed protective chamber, and combining multiple sealing structures, the high efficiency of the sealed space is ensured, and the water and oxygen content in the processing area atmosphere is controllable; an active temperature control system is designed and integrated, which improves the problem of low-temperature deformation of the machine tool main structure caused by the introduction of cryogenic media; an innovative cryogenic media internal spray turret scheme is proposed, which realizes the directional supply of cryogenic media to the working tool during automatic tool changing, and solves the integration problem of cryogenic media internal spray cooling function with conventional lathe functions; the cryogenic media transmission vacuum pipeline is rationally laid out, ensuring the thermal insulation transmission of cryogenic media without affecting the original structural compactness and freedom of motion; the integrated cryogenic media control system with the CNC machine tool achieves stable and controllable pressure and flow rate during cryogenic media transmission. Attached Figure Description

[0017] Figure 1 This is a front view of the slant bed lathe main unit; Figure 2 This is a right view of the slant bed lathe main unit; Figure 3 This is a top view of the slant bed lathe main unit; Figure 4 Rear view of a cryogenic cooling lathe with a closed operating space; Figure 5 This is a front view of a closed-loop cryogenic cooling lathe. Figure 6 Axonometric drawing of a sealed protective chamber; Figure 7 For the sealed protective cabin Figure 6 A magnified view of the part circled in the image; Figure 8 This is an axonometric drawing of the bed. Figure 9 This is a structural diagram of the vacuum adsorption spindle; Figure 10This is a schematic diagram of a cryogenic medium internal spray knife turret. Figure 11 This is a cross-sectional view of a cryogenic medium internal spray knife turret along AA. Figure 12 This is a left-side view of a cryogenic medium internal spray knife turret. Figure 13 For cryogenic medium internal spray turrets Figure 12 A magnified view of the part circled in the image; In the diagram: 1. Turret mount; 2. Spindle; 3. Bed; 4. Spindle mount; 5. Spindle guard plate; 6. First sealing ring; 7. Spindle motor; 8. Belt assembly; 9. First vacuum hose; 10. First copper connector; 11. Transmission block; 12. Sealed protective chamber; 13. Flange mating edge; 14. Upper surface of bed; 15. First sealing ring groove; 16. First sealing strip; 17. Second sealing strip; 18. Second sealing ring groove; 19. First bolt; 20. Spindle mount mounting surface; 21. Z-axis guide rail; 22. Z-axis guide rail mounting surface; 23. Z-axis slider; 24. Saddle; 25. Lower surface; 26. Z-axis motor; 27. Z-axis lead screw; 28. Upper surface of saddle; 29. ​​X-axis guide rail; 30. X-axis slider; 31 Lower surface of turret holder; 32 X-axis motor; 33 X-axis lead screw; 34 Chip receiving tray; 35 Chip receiving groove; 36 Self-pressurized liquid nitrogen tank; 37 Discharge valve; 38 First nut; 39 Second vacuum hose; 40 Second nut; 41 Stainless steel rigid tube; 42 Pressure reducing valve; 43 Flow meter; 44 Safety valve; 45 Regulating valve; 46 Temperature sensor; 47 Pressure sensor; 48 Polyurethane foam layer; 49 Third nut; 50 Vacuum rigid tube; 51 Fourth nut; 52 Second sealing ring; 53 Fastening hoop; 54 Control unit housing; 55 Valve actuator; 56 Bracket; 57 Data acquisition and transmission module; 58 Quick-lift 59. Door; 60. Gas spring bracket; 61. First interface; 62. Second interface; 63. Locking buckle; 64. Transition chamber; 65. Exhaust pipe; 66. Gas supply pipe; 67. Water analyzer; 68. Oxygen analyzer; 69. Nitrogen analyzer; 70. Heating block; 71. Protective shell; 72. Second bolt; 73. Circulating fan; 74. Adapter; 75. Temperature control channel; 76. Inlet; 77. Outlet; 78. Three-jaw chuck; 79. Vacuum rod; 80. Through hole; 81. Hollow channel; 82. Connecting female; 83. Rotary joint; 84. Turret housing; 85. Directional disc; 86. Third bolt; 87. Tool head; 88. External turning tool holder; 89. Tool slot; 80. Wedge clamping block ; 90 Fourth bolt; 91 Tool holder; 92 Boring tool bar; 93 Fifth bolt; 94 First liquid nitrogen transfer hose; 95 Second copper connector; 96 Third copper connector; 97 Jet head; 98 Second liquid nitrogen transfer hose; 99 Fourth copper connector; 100 Fifth copper connector; 101 Vacuum adsorption fixture; 102 Connecting male connector; 103 Connecting straight connector; 104 Spherical shell workpiece; 105 Vacuum adsorption cavity; 106 Transition chamber door; 107 Glove opening; 108 Inner flow channel of transfer block; 109 Inner flow channel of first direction selector plate; 110 First jet port; 111 Inner flow channel of second direction selector plate; 112 Inner flow channel of boring tool bar; 113 Second jet port. Detailed Implementation

[0018] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings and technical solutions.

[0019] In this embodiment, the cryogenic medium is liquid nitrogen with a minimum temperature of -196℃; the temperature control medium is water at 30℃; the cryogenic medium internal spray cooling CNC lathe has a 60-degree slant bed, external dimensions of 3800 / 1500 / 2300mm, a maximum turning diameter of 300mm, a maximum turning diameter of 210mm, and maximum X / Z axis travel of 200 / 1000mm; the cryogenic medium internal spray turret has a center height of 1100mm, 8T of tools, a tool change and locking time of 0.6s for adjacent tools, a tool change and locking time of 1.6s for the furthest tool, and a repeatability of 0.003mm; the self-pressurized liquid nitrogen tank 2.1 has a nominal volume of 175L and a maximum working pressure of 2.4MPa; the regulating valve 2.10 contains liquid nitrogen. The flow rate is adjustable from 0 to 80 L / h with an adjustment accuracy of ±1 L / h; the liquid nitrogen pressure of the pressure reducing valve 2.7 is adjustable from 0.1 to 1.8 MPa with an adjustment accuracy of ±0.1 MPa; the safety valve 2.9 has a set pressure of 2.0 MPa; the diameter of the first vacuum tube 2.15 and the second vacuum tube 3.24 is 16 mm, and their thermal conductivity is approximately 0; the transmission tube 4.6 is made of modified polytetrafluoroethylene with a thermal conductivity of less than 0.15 W / (m·K); the heating block 4.1 has a power of 2.5 kW; the circulating fan 4.4 has a speed of 500 rpm; during operation, the oxygen content in the sealed protective chamber is <2%, the water content is <1%, and the pressure is 985-1000 mbr (slight negative pressure).

[0020] The assembly process of the enclosed-space cryogenic cooling lathe is as follows: Figure 1 , 2 As shown in figures 3, 4, 5, 7, 8, 9, 10, 11, 12, and 13, the first step involves installing the second sealing strip 17 into the second sealing ring groove 18 on the bed 3, fixing the spindle guard plate 5 to the bed 3 using the first bolt 19 and pressing the second sealing strip 17; fixing the spindle seat 4 onto the spindle seat mounting surface 20 of the bed 3; fixing the two Z-axis guide rails 21 onto the Z-axis guide rail mounting surface 22 of the bed 3; and installing the four Z-axis sliders 23 onto the lower surface 25 of the slide saddle 24. The X-axis slider 23 slides with the Z-axis guide rail 21, and the power comes from the Z-axis motor 26 and the Z-axis lead screw 27. Two X-axis guide rails 29 are fixed on the upper surface 28 of the slide saddle, and four X-axis sliders 30 are installed on the lower surface 31 of the turret. The X-axis sliders 30 slide with the X-axis guide rails 29, and the power comes from the X-axis motor 32 and the X-axis lead screw 33. The chip tray 34 is placed in the chip groove 35 on the bed 3 for chip collection. Thus, the assembly of the slant bed lathe main body is completed. The second step involves connecting the outlet valve 37 on the self-pressurized liquid nitrogen tank 36 to the second vacuum hose 39 via the first nut 38. The second vacuum hose 39 is then connected to one end of the stainless steel rigid tube 41 via the second nut 40. A pressure reducing valve 42, a flow meter 43, a safety valve 44, a regulating valve 45, a temperature sensor 46, and a pressure sensor 47 are sequentially connected to the stainless steel rigid tube 41. The stainless steel rigid tube 41 is then wrapped with a polyurethane foam layer 48. The other end of the stainless steel rigid tube 41 is connected to one end of the vacuum rigid tube 50 via the third nut 49. Next, the other end of the vacuum rigid tube 50 is connected to the first vacuum hose 9 via the fourth nut 51; the vacuum rigid tube 50 and the main shaft protective plate 5 are sealed by the second sealing ring 52; the stainless steel rigid tube 41 is fixed to the control unit box 54 by several fastening hoops 53; the valve actuator 55 of the regulating valve 45 is reinforced to the control unit box 54 by the bracket 56, and the data acquisition and transmission module 57 is fixed to the control unit box 54; thus, the assembly of the cryogenic medium thermal insulation transmission control system is completed. The third step involves installing the two quick-lift hatches 58 on the front of the sealed protective chamber 12 via hinges; fixing the two ends of the gas spring bracket 59 to the first interface 60 on the sealed protective chamber 12 and the second interface 61 on the quick-lift hatches 58 respectively; installing several locking buckles 62 on the quick-lift hatches 58; installing the transition chamber 63 on the right side of the sealed protective chamber 12 via a flange; fixing the exhaust pipe 64 and the gas transmission pipe 65 to the rear of the sealed protective chamber 12; and installing the water analyzer 66, oxygen analyzer 67, and nitrogen analyzer 68 on the top of the sealed protective chamber 12. This completes the assembly of the sealed protective chamber. Fourth step: Fix the heating block 69 to the inner surface of the top of the sealed protective chamber 12, cover the heating block 69 with the protective shell 70, and fix it to the sealed protective chamber 12 with the second bolt 71; install the circulating fan 72 to the bottom of the protective shell 70; install the conversion connector 73 to the inlet 75 and outlet 76 of the temperature control channel 74 inside the bed 3 for connection with the conveying pipeline of the temperature control medium; thus, the assembly of the active temperature control system is completed. Fifth step, fix the three-jaw chuck 77 to the nose end of the spindle 2; push the vacuum pull rod 78 into the hollow channel 80 of the spindle 2 through the through hole 79 on the three-jaw chuck 77; fix the connecting female head 81 to the head end of the vacuum pull rod 78, and install the rotary joint 82 to the tail end of the vacuum pull rod 78 for connection with the transmission pipe of the vacuum source; at this point, the assembly of the vacuum adsorption spindle is completed. Step 6: Fix the transmission block 11 to the turret housing 83; fix the directional plate 84 to the cutter head 86 with the third bolt 85; insert the outer turning tool bar 87 into the tool slot 88 on the cutter head 86, push the wedge clamping block 89 into the tool slot 88 on the cutter head 86, and fasten the wedge clamping block 89 to the cutter head 86 with the fourth bolt 90; fix the tool holder 91 to the cutter head 86; push the boring tool bar 92 into the tool holder 91 and tighten it with the fifth bolt 93; connect one end of the first liquid nitrogen transmission hose 94 to the directional plate 84 through the second copper connector 95, and connect the other end to the jet head 97 on the outer turning tool bar 87 through the third copper connector 96; connect one end of the second liquid nitrogen transmission hose 98 to the directional plate 84 through the fourth copper connector 99, and connect the other end to the tail end of the boring tool bar 92 through the fifth copper connector 100; thus, the assembly of the cryogenic medium internal spray turret is completed; Step 7: Fix the turret housing 83 to the turret base 1 with bolts. This completes the connection between the slant bed lathe and the cryogenic medium internal spray turret. Step 8: Push the spindle 2 into the spindle seat 4. The rotational seal between the spindle 2 and the spindle guard plate 5 is achieved by the first sealing ring 6. The spindle 2 is driven by the spindle motor 7 and the belt group 8. At this point, the connection between the slant bed lathe main body and the vacuum adsorption spindle is completed. Step 9: Connect the first vacuum hose 9 to the transmission block 11 of the cryogenic medium internal spray turret via the first copper connector 10. This completes the connection between the cryogenic medium thermal insulation transmission control system and the cryogenic medium internal spray turret. Step 10: Install the first sealing strip 16 onto the first sealing ring groove 15 on the flange mating edge 13 of the sealed protective chamber 12; then install the sealed protective chamber 12 onto the upper surface 14 of the bed through the flange mating edge 13, thereby pressing the first sealing strip 16 to achieve a sealing and isolation function; at this point, the connection between the slant bed lathe main machine and the sealed protective chamber is completed. When the machine tool clamps the workpiece, first connect the male connector 102 and the female connector 81 on the vacuum adsorption fixture 101; then use the three-jaw chuck 77 to clamp the straight connector 103 of the vacuum adsorption fixture 101. The spherical workpiece 104 and the vacuum adsorption fixture 101 together form a closed vacuum adsorption cavity 105, thereby using the adsorption force generated by the vacuum negative pressure to achieve stable clamping of the spherical workpiece 104. During machine tool processing, first open the transition chamber door 106 of the transition chamber 63 to transport the workpiece to be processed into the sealed protective chamber 12, and then close the transition chamber door 106; clamp the workpiece to be processed into the three-jaw chuck 77 through the glove opening 107; connect the nitrogen source to the gas supply pipe 65 and the exhaust pipe 64 to the workshop exhaust to replace the moisture and oxygen in the sealed protective chamber 12; then the cryogenic medium flows out from the self-pressurized liquid nitrogen tank 36, and sequentially passes through the second vacuum hose 39, the stainless steel rigid pipe 41, the vacuum rigid pipe 50, the first vacuum hose 9, the internal flow channel 108 inside the transfer block 11, and the first... The liquid nitrogen is directed through the flow channel 109 and the first liquid nitrogen transfer hose 94, and finally ejected from the first jet port 110 at the front end of the jet head 97 for cryogenic cooling processing. During the cryogenic cooling process, the heating function of the heating block 69 is turned on, and the hot and cold gases in the sealed protective chamber 12 are mixed by the circulating fan 72 to improve the low-temperature deformation of the machine tool caused by the continuous jet of the cryogenic medium. After the cryogenic cooling process is completed, the processed workpiece and the chip receiving plate 34 are transferred to the outside of the sealed protective chamber 12 through the transition chamber 63. Then, the processed chips in the chip receiving plate 34 are treated in accordance with regulations to complete the cryogenic cooling process. When the machine tool automatically switches from the external turning tool holder 87 to the boring tool holder 92, the tool head 86 moves axially away from the turret housing 83, interrupting the flow channel 108 inside the transmission block 11 and the first flow channel 109 inside the direction selector plate 84. After rotating a certain angle, the tool head 86 moves axially towards the turret housing 83, connecting the flow channel 108 inside the transmission block 11 with the second flow channel 111 inside the direction selector plate 84. After that, the cryogenic medium can pass through the second liquid nitrogen transmission hose 98 and the flow channel 112 inside the boring tool holder 92, and finally be ejected from the second jet port 113 at the front end of the boring tool holder 92, completing the directional supply of cryogenic medium to the working tool that also has an automatic tool changing function. This invention employs a closed-environment, cryogenic cooling turning process, enabling control and regulation of the atmosphere composition in the machining area. An active temperature control system is added to achieve proactive control of the closed environment and the machine tool's temperature field. Utilizing a cryogenic medium-in-the-place turret design, it achieves efficient, point-to-point cooling of the cutting area during turning, while ensuring the directional transmission of the cryogenic medium to the cutting tool and balancing it with automatic tool changing. The effective integration of the CNC lathe with cryogenic medium transmission and control fulfills the precise controllable cooling flow requirements for different parts. This lathe design facilitates the implementation of a new cryogenic cooling and clean machining process for special materials, and is expected to enhance my country's manufacturing capabilities for core components in key sectors.

[0021] 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 cooling lathe with a sealed operating space, characterized in that, The enclosed cryogenic cooling lathe mainly consists of a slant bed lathe main unit, a cryogenic medium heat insulation and transmission control system, a sealed protective chamber, a temperature active control system, a vacuum adsorption spindle, and a cryogenic medium internal spray turret. The cryogenic medium internal spray turret is installed on the turret seat (1) of the slant bed lathe main unit and is used to clamp the tool and spray the cryogenic medium into the cutting zone. The vacuum adsorption spindle (2) is installed on the spindle seat (4) on the bed (3) of the slant bed lathe main unit. The spindle (2) is sealed to the spindle guard plate (5) by a first sealing ring (6). The spindle (2) is connected to the spindle motor (7) and the spindle protection plate (5). The belt assembly (8) drives the ultra-low temperature medium thermal insulation transmission control system, which is connected to the transmission block (11) of the ultra-low temperature medium internal spray turret through the first vacuum hose (9) and the first copper connector (10); the sealed protective chamber (12) of the sealed protective chamber is installed on the upper surface (14) of the bed through the flange mating edge (13). The flange mating edge (13) is provided with a first sealing ring groove (15), and the first sealing strip (16) is provided in the first sealing ring groove (15). When the flange mating edge (13) is connected to the bed (3), the first sealing strip (16) is pressed to achieve the sealing isolation between the sealed protective chamber and the bed (3).

2. The closed-space cryogenic cooling lathe according to claim 1, characterized in that, The structure of the slant bed lathe main unit is as follows: the second sealing strip (17) is installed in the second sealing ring groove (18) on the bed (3), and the spindle guard plate (5) is fixed to the bed (3) by the first bolt (19) and the second sealing strip (17) is pressed; the spindle seat (4) is fixed on the spindle seat mounting surface (20) of the bed (3); the two Z-axis guide rails (21) are fixed on the Z-axis guide rail mounting surface (22) of the bed (3); and the four Z-axis sliders (23) are installed on the lower surface (25) of the slide saddle (24). The Z-axis slider (23) slides with the Z-axis guide rail (21), and the power comes from the Z-axis motor (26) and the Z-axis lead screw (27). Two X-axis guide rails (29) are fixed on the upper surface (28) of the slide saddle, and four X-axis sliders (30) are installed on the lower surface (31) of the turret. The X-axis sliders (30) slide with the X-axis guide rails (29), and the power comes from the X-axis motor (32) and the X-axis lead screw (33). The chip receiving plate (34) is placed in the chip receiving groove (35) on the bed (3) for recycling chips.

3. The closed-space cryogenic cooling lathe according to claim 2, characterized in that, The structure of the cryogenic medium thermal insulation transmission control system is as follows: the outlet valve (37) on the self-pressurized liquid nitrogen tank (36) is connected to the second vacuum hose (39) via the first nut (38), and the second vacuum hose (39) is connected to one end of the stainless steel rigid pipe (41) via the second nut (40); the stainless steel rigid pipe (41) is sequentially connected to a pressure reducing valve (42), a flow meter (43), a safety valve (44), a regulating valve (45), a temperature sensor (46), and a pressure sensor (47), and the stainless steel rigid pipe (41) is wrapped with a polyurethane foam layer (48); the stainless steel rigid pipe (41) is further... One end is connected to one end of the vacuum tube (50) via the third nut (49), and the other end of the vacuum tube (50) is connected to the first vacuum hose (9) via the fourth nut (51); the vacuum tube (50) and the main shaft guard plate (5) are sealed by the second sealing ring (52); the stainless steel tube (41) is fixed to the control unit box (54) by several fastening hoops (53); the valve actuator (55) of the regulating valve (45) is reinforced to the control unit box (54) by the bracket (56), and the data acquisition and transmission module (57) is fixed to the control unit box (54).

4. The closed-space cryogenic cooling lathe according to claim 3, characterized in that, The structure of the sealed protective chamber is as follows: two quick-lift doors (58) are installed on the front side of the sealed protective chamber body (12) by hinges; the two ends of the gas spring bracket (59) are fixed to the first interface (60) on the sealed protective chamber body (12) and the second interface (61) on the quick-lift door (58) respectively; several locking buckles (62) are installed on the quick-lift door (58); the transition chamber (63) is installed on the right side of the sealed protective chamber body (12) by flange; the exhaust pipe (64) and the gas transmission pipe (65) are fixed to the rear side of the sealed protective chamber body (12); the water analyzer (66), oxygen analyzer (67), and nitrogen analyzer (68) are installed on the top of the sealed protective chamber body (12).

5. The closed-space cryogenic cooling lathe according to claim 4, characterized in that, The structure of the active temperature control system is as follows: the heating block (69) is fixed on the inner surface of the top of the sealed protective chamber (12), the protective shell (70) covers the outside of the heating block (69) and is fixed to the sealed protective chamber (12) by the second bolt (71); the circulating fan (72) is installed at the bottom of the protective shell (70); the conversion connector (73) is installed at the inlet (75) and outlet (76) of the temperature control channel (74) inside the bed (3) for connecting with the conveying pipeline of the temperature control medium.

6. The closed-space cryogenic cooling lathe according to claim 5, characterized in that, The structure of the vacuum adsorption spindle is as follows: a three-jaw chuck (77) is fixed to the nose end of the spindle (2); a vacuum pull rod (78) is pushed into the hollow channel (80) of the spindle (2) through the through hole (79) on the three-jaw chuck (77); a connecting female head (81) is fixed to the head end of the vacuum pull rod (78), and a rotary joint (82) is installed to the tail end of the vacuum pull rod (78) for connection with the transmission pipe of the vacuum source.

7. The closed-space cryogenic cooling lathe according to claim 6, characterized in that, The structure of the cryogenic medium internal spray turret is as follows: the transmission block (11) is fixedly connected to the turret housing (83); the orientation plate (84) is fixed to the cutter head (86) by the third bolt (85); the outer turning tool bar (87) is inserted into the tool slot (88) on the cutter head (86), the wedge-shaped clamping block (89) is pushed into the tool slot (88) on the cutter head (86), and the wedge-shaped clamping block (89) is fastened to the cutter head (86) by the fourth bolt (90); the tool holder (91) is fixedly connected to the cutter head (86). Connect; push the boring bar (92) into the tool holder (91) and tighten it with the fifth bolt (93); one end of the first liquid nitrogen transmission hose (94) is connected to the direction selector (84) through the second copper connector (95), and the other end is connected to the jet head (97) on the external turning tool bar (87) through the third copper connector (96); one end of the second liquid nitrogen transmission hose (98) is connected to the direction selector (84) through the fourth copper connector (99), and the other end is connected to the tail end of the boring bar (92) through the fifth copper connector (100).

8. The closed-space cryogenic cooling lathe according to claim 7, characterized in that, When the workpiece is clamped on the closed-space cryogenic cooling lathe, the male connector (102) on the vacuum adsorption fixture (101) is first paired with the female connector (81); then the three-jaw chuck (77) is used to clamp the straight connector (103) of the vacuum adsorption fixture (101). The spherical workpiece (104) and the vacuum adsorption fixture (101) together form a closed vacuum adsorption cavity (105), thereby using the adsorption force generated by the vacuum negative pressure to achieve stable clamping of the spherical workpiece (104).

9. The closed-space cryogenic cooling lathe according to claim 7, characterized in that, When the cryogenic cooling lathe with a sealed operating space is used for cryogenic cooling processing, first open the transition chamber door (106) of the transition chamber (63), transport the workpiece to be processed to the sealed protective chamber (12), and close the transition chamber door (106); clamp the workpiece to be processed to the three-jaw chuck (77) through the glove opening (107); connect the nitrogen source to the gas supply pipe (65) and the exhaust pipe (64) to the workshop exhaust, and replace the moisture and oxygen in the sealed protective chamber (12); then the cryogenic medium flows out from the self-pressurized liquid nitrogen tank (36), and passes through the second vacuum hose (39), stainless steel hard pipe (41), vacuum hard pipe (50), first vacuum hose (9), and the internal flow channel of the transfer block (11) in sequence. 108) The first flow channel (109) inside the first direction selector plate (84) and the first liquid nitrogen transmission hose (94) are finally ejected from the first jet port (110) at the front end of the jet head (97) for cryogenic cooling processing; During the cryogenic cooling processing, the heating function of the heating block (69) is turned on, and the hot and cold gases in the sealed protective chamber (12) are mixed by the circulating fan (72) to improve the low temperature deformation of the machine tool caused by the continuous jet of the cryogenic medium; After the cryogenic cooling processing is completed, the processed workpiece and the chip receiving plate (34) are transferred to the outside of the sealed protective chamber (12) through the transition chamber (63), and then the processing chips in the chip receiving plate (34) are processed in accordance with regulations to complete the cryogenic cooling processing.

10. The closed-space cryogenic cooling lathe according to claim 7, characterized in that, When the operating space-sealed cryogenic cooling lathe automatically changes tools, when it automatically switches from the external turning tool holder (87) to the boring tool holder (92), the tool head (86) moves axially away from the turret housing (83), causing the flow channel (108) inside the transfer block (11) to be interrupted from the flow channel (109) inside the first direction selection plate (84); after the tool head (86) rotates a certain angle, it moves axially towards the turret housing (83). The movement connects the inner flow channel (108) of the transmission block (11) with the inner flow channel (111) of the second direction selector disk (84). After that, the cryogenic medium can be ejected from the second jet port (113) at the front end of the boring bar (92) through the second liquid nitrogen transmission hose (98) and the inner flow channel (112) of the boring bar (92), thus completing the directional supply of cryogenic medium to the working tool that also has the function of automatic tool changing.

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