An all-ceramic bearing assembly device suitable for extreme cryogenic wind tunnel spindle systems

Abstract

This invention belongs to the field of all-ceramic bearing assembly technology and discloses an all-ceramic bearing assembly device suitable for extreme low-temperature wind tunnel spindle systems. It includes a vertical frame with guide rails mounted on it, and a compressor spindle slidably mounted on the guide rails via shaft clamps. Through the precise cooperation of the vertical frame and guide rails, this invention enables the compressor spindle to move smoothly and accurately up and down along the guide rails. The structure, with the opening at the top of the liquid nitrogen cooling tank coaxial with the compressor spindle, solves the problems of existing horizontal cold-assembly equipment in achieving deep cryogenic immersion treatment of the shaft and inability to achieve uniform and sufficient cooling of the shaft, thus avoiding uneven shaft diameter shrinkage. Through precise control of the drive input shaft and ball screw, a high degree of controllability in the cooling and assembly process is achieved, improving the problem of poor controllability in the cooling and assembly process. Ultimately, this significantly improves assembly accuracy and work efficiency, meeting assembly requirements.

Description

Technical Field

[0001] This invention belongs to the field of all-ceramic bearing assembly technology, specifically an all-ceramic bearing assembly device suitable for extreme low temperature wind tunnel spindle systems. Background Technology

[0002] The assembly of all-ceramic bearings in the spindle system of an extreme low-temperature wind tunnel refers to the precision process of integrating bearing components made of ceramic materials (such as silicon nitride or zirconium oxide) into the spindle system of a wind tunnel in an ultra-low temperature environment.

[0003] Currently, in the assembly process of all-ceramic bearings for extreme cryogenic wind tunnel spindle systems, the interference fit assembly of bearings and shafts is widely used in the field of mechanical manufacturing. It is a key process to ensure the operational stability of mechanical components. Traditional assembly methods mainly adopt hot fitting and press fitting. The hot fitting method requires heating the bearing or shaft, which can easily change the metallographic structure of the bearing material and reduce the bearing's service life. The press fitting method completes the assembly by applying external mechanical force, which can easily cause mechanical damage to key components such as bearing raceways and cages, and it is difficult to ensure the coaxiality of the shaft and bearing housing. Existing cold fitting equipment is mostly horizontal in structure, which makes it difficult to achieve deep cryogenic immersion treatment of the shaft, and cannot achieve a uniform and sufficient cooling effect on the shaft body. It can easily cause uneven shaft diameter shrinkage, and the shaft is prone to bending deformation during the assembly process. The alignment of the bearing housing and shaft is difficult, and the controllability of the cooling and assembly process is poor. Ultimately, this leads to low assembly accuracy and poor work efficiency, which cannot meet the assembly requirements. Therefore, an all-ceramic bearing assembly device suitable for extreme cryogenic wind tunnel spindle systems is proposed. Summary of the Invention

[0004] To address the problems mentioned in the background art, the present invention provides an all-ceramic bearing assembly device suitable for extreme low temperature wind tunnel spindle systems. This device solves the problem that existing cold assembly equipment is mostly horizontal in structure, making it difficult to achieve deep cryogenic immersion treatment of the shaft, resulting in uneven and insufficient cooling of the shaft body and uneven shaft diameter shrinkage.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an all-ceramic bearing assembly device suitable for an extreme low-temperature wind tunnel spindle system, comprising a vertical frame, a guide rail mounted on the vertical frame, a compressor spindle slidably mounted on the guide rail via a shaft clamp, and a drive input shaft and a ball screw provided on the vertical frame, the drive input shaft being connected to the end of the ball screw via a coupling; When the drive input shaft rotates, the compressor main shaft and its connected shaft clamp are driven to make axial feed motion along the guide rail through the helical transmission action of the ball screw; The vertical frame is equipped with a bearing housing fixture, and the all-ceramic bearing is mounted on the bearing housing fixture through the bearing housing, and the bearing housing is coaxial with the compressor main shaft; A liquid nitrogen cooling tank is mounted on a vertical frame, and the compressor main shaft is coaxial with the opening at the top of the liquid nitrogen cooling tank. The compressor main shaft is mounted on the shaft clamp. Rotating the drive input shaft and ball screw causes the compressor main shaft to move downwards along the guide rail and extend into the liquid nitrogen cooling tank for freezing. The compressor main shaft moves along the guide rail by rotating the drive input shaft in the opposite direction. The all-ceramic bearing is installed on the bearing housing fixture through the bearing housing. Then, the drive input shaft is rotated to move the compressor main shaft down and assemble it with the all-ceramic bearing.

[0006] Preferably, a sealing assembly is installed on the top of the liquid nitrogen cooling tank, a guide assembly is provided inside the sealing assembly, and a sealing assembly is installed on the top inside the sealing assembly; The sealing component comes into contact with the sealing component under the action of the guiding component, thereby sealing the opening at the top of the liquid nitrogen cooling tank.

[0007] Preferably, the sealing assembly includes a docking frame fixed to the top of the liquid nitrogen cooling tank, and a receiving frame is installed on the top of the docking frame; The docking frame and the receiving frame are connected to the liquid nitrogen cooling tank, and the top of the receiving frame is threaded with a cover plate.

[0008] Preferably, the guiding assembly includes a guide frame installed inside the docking frame; The sealing assembly also includes a sealing plate, the top of which is fixedly fitted with a sealing plug; The guide frame has a guide groove, and the end of the sealing plate slides in the guide groove through a protrusion.

[0009] Preferably, the sealing plate, sealing plug, and guide assembly are symmetrically installed inside the docking frame, and sealing gaskets are provided on the opposite surfaces of the two sealing plugs.

[0010] Preferably, the guide assembly further includes a fixed plate fixed inside the guide frame, a transmission rod is movably sleeved on the fixed plate, and a sliding groove is provided at the end of the sealing plate, and the transmission rod slides in the sliding groove through a connecting slide member.

[0011] Preferably, a transmission plate is installed at the top of the transmission rod, and an elastic element supporting the transmission plate is provided at the top of the fixed plate; A stabilizing rod is movably sleeved at the end of the sealing plate, and the stabilizing rod slides within the guide frame.

[0012] Preferably, the guide groove is composed of a vertical end and an inclined end; In the initial state, under the action of the elastic element, the sealing plate is positioned in the vertical end of the guide groove by the protrusion, so that the two sealing plugs form a frustum and the two sealing gaskets fit together, and the frustum is sleeved on the bottom of the sealing assembly to achieve sealing; The top and bottom of the two sealing plugs that form a frustum are both concave.

[0013] Preferably, the sealing assembly includes a metal elastic element fixed inside the receiving frame. The metal elastic element is corrugated, and the inner diameter of the metal elastic element gradually increases from top to bottom. A slide is installed at the bottom of the metal elastic element, and the slide slides on the bottom of the receiving frame. A gasket is mounted on the annular protrusion at the uppermost end of the inner wall of the metal elastic element via a first mating member annular array.

[0014] Preferably, the two annular protrusions at the lower end of the inner wall of the metal elastic element are provided with snap-fit ​​members through a second mating member annular array, and the inner wall of the snap-fit ​​members is provided with a sealing ring; When the sealing block assembly forms a frustum fitted onto the lower end of the metal elastic element, the outer wall of the frustum contacts the inner wall of the sealing ring.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, through the precise matching of a vertical frame and guide rails, enables the compressor main shaft to move smoothly and accurately up and down along the guide rails. The vertical structure design avoids the phenomenon of shaft bending and deformation that is common in traditional horizontal equipment, overcoming the technical problem of shaft bending and deformation. By adopting a structure in which the opening at the top of the liquid nitrogen cooling tank is coaxial with the compressor main shaft, it achieves immersion-type deep cryogenic treatment of the compressor main shaft. This solves the problem that existing horizontal cold assembly equipment cannot achieve immersion-type deep cryogenic treatment of the shaft and cannot achieve a uniform and sufficient cooling effect, thus avoiding uneven shaft diameter shrinkage. Through precise control of the drive input shaft and ball screw, a high degree of controllability of the cooling and assembly process is achieved, improving the problem of poor controllability of the cooling and assembly process. Ultimately, it significantly improves assembly accuracy and work efficiency, meeting assembly requirements.

[0016] This invention uses two sealing plugs forming a truncated cone, which is fitted at the bottom of a sealing assembly. The two sealing gaskets fit together to seal the liquid nitrogen cooling tank. The compressor main shaft moves downward and contacts the top surface of the truncated cone, pushing the sealing plate down along the guide groove through the protrusion to the inclined end. The two sealing plugs move outward and open the opening, achieving automatic opening without manual operation, thus improving the degree of automation. After freezing is completed, the compressor main shaft moves upward and disengages. The elastic element releases its elastic potential energy and pushes the transmission plate upward. The two sealing plates move upward along the guide groove, and the protrusion slides from the inclined end to the vertical end. The two sealing plugs reform the truncated cone and fit together, achieving automatic sealing, reducing liquid nitrogen evaporation, improving utilization efficiency, and saving costs.

[0017] The sealing assembly of this invention achieves dynamic sealing through a corrugated elastic structure and a conical inner diameter design. When the shaft passes through, the inner diameter of the metal elastic element gradually increases from top to bottom, forming a conical channel. This ensures that the compressor main shaft does not contact the sealing ring when passing through, preventing the sealing ring from hardening and becoming brittle due to the low temperature of the shaft, thus extending the service life of the sealing ring. At the same time, the upper gasket reduces the gap between itself and the shaft, minimizing the opening cross-sectional area while ensuring smooth passage, thereby reducing the evaporation rate of liquid nitrogen. After the shaft detaches, the metal elastic element automatically contracts due to its elastic restoring performance, and the sealing ring re-fits the truncated cone, achieving automatic restoration of the sealing state without manual intervention, ensuring the sealing reliability of the liquid nitrogen cooling tank in the non-working state. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall appearance and structure of the present invention; Figure 2 This is a schematic diagram of the structure of the liquid nitrogen cooling tank and the vertical frame of the present invention. Figure 3 This is a schematic diagram of the external structure of the liquid nitrogen cooling tank of the present invention; Figure 4 This is a schematic diagram of the external structure of the sealing component of the present invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the plugging component and sealing component of the present invention; Figure 6 This is a schematic diagram of the mating structure of the sealing assembly, plugging assembly, and guiding assembly of the present invention; Figure 7 This is a schematic diagram showing the disassembled structure of the sealing component and the guiding component of the present invention; Figure 8 This is a schematic diagram of the cross-sectional fit between the sealing component and the guiding component of the present invention; Figure 9 This is a schematic diagram of the cross-sectional structure of the sealing component of the present invention.

[0019] In the diagram: 1. Vertical frame; 2. Guide rail; 3. Ball screw; 4. Drive input shaft; 5. Compressor spindle; 6. Shaft clamp; 7. Bearing seat clamp; 8. Bearing seat; 9. Liquid nitrogen cooling tank; 10. Sealing assembly; 101. Connecting frame; 102. Cover plate; 103. Receiving frame; 104. Guide groove; 105. Sealing plate; 106. Sealing plug; 107. Sealing gasket; 108. Protrusion; 11. Sealing assembly; 111. Metal elastic element; 112. First connecting piece; 113. Gasket; 114. Second connecting piece; 115. Snap-fit ​​element; 116. Sealing ring; 117. Slide; 12. Guide assembly; 121. Guide frame; 122. Fixing plate; 123. Transmission plate; 124. Elastic element; 126. Transmission rod; 127. Slide groove; 128. Stabilizing rod; 129. Connecting slide. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figures 1 to 9 As shown, the present invention provides an all-ceramic bearing assembly device suitable for the main shaft system of an extreme low temperature wind tunnel, including a vertical frame 1, a guide rail 2 installed on the vertical frame 1, a compressor main shaft 5 slidably mounted on the guide rail 2 via a shaft clamp 6, and a drive input shaft 4 and a ball screw 3 provided on the vertical frame 1, the drive input shaft 4 being connected to the end of the ball screw 3 via a coupling; When the drive input shaft 4 rotates, the compressor main shaft 5 and its connected shaft clamp 6 are driven to make axial feed motion along the guide rail 2 through the helical transmission action of the ball screw 3. A bearing housing fixture 7 is installed on the vertical frame 1. The all-ceramic bearing is installed on the bearing housing fixture 7 through the bearing housing 8, and the bearing housing 8 is coaxial with the compressor main shaft 5. Liquid nitrogen cooling tank 9 is mounted on vertical frame 1, and compressor main shaft 5 is coaxial with the opening at the top of liquid nitrogen cooling tank 9; The compressor main shaft 5 is mounted on the shaft clamp 6. Rotating the drive input shaft 4 and the ball screw 3 causes the compressor main shaft 5 to move downwards along the guide rail 2 and extend into the liquid nitrogen cooling tank 9 for freezing. The reverse rotation of the drive input shaft 4 causes the compressor main shaft 5 to move along the guide rail 2. The all-ceramic bearing is mounted on the bearing housing fixture 7 via the bearing housing 8. Then, the drive input shaft 4 is rotated to move the compressor main shaft 5 down to assemble with the all-ceramic bearing.

[0022] The compressor spindle 5 is mounted on the shaft clamp 6. Through the precise fit of the vertical frame 1 and the guide rail 2, the shaft clamp 6 drives the compressor spindle 5 to move smoothly and accurately up and down along the guide rail 2. The structural design of the vertical frame 1 and the guide rail 2 ensures the stability and accuracy of the compressor spindle 5 during movement, avoiding the problem of shaft bending and deformation that is common in traditional horizontal equipment. Rotating the drive input shaft 4 and the ball screw 3 drives the compressor spindle 5 to move downwards along the guide rail 2, allowing the compressor spindle 5 to gradually penetrate into the liquid nitrogen cooling tank 9. Since the opening at the top of the liquid nitrogen cooling tank 9 is coaxial with the compressor spindle 5, the compressor spindle 5 can fully contact the liquid nitrogen. Through the deep cooling effect of the liquid nitrogen, the shaft diameter of the compressor spindle 5 shrinks uniformly. Maintaining this for a certain period of time allows the shaft to cool fully, solving the problem that existing horizontal cold assembly equipment cannot achieve deep cooling treatment of the shaft by immersion and cannot achieve a uniform and sufficient cooling effect. This avoids the phenomenon of uneven shaft diameter shrinkage and creates good conditions for subsequent assembly.

[0023] After the temperature of the compressor main shaft 5 stabilizes and it shrinks to the required size, the drive input shaft 4 and ball screw 3 are rotated in the opposite direction to move the compressor main shaft 5 upward along the guide rail 2 and remove it from the liquid nitrogen cooling tank 9. At this time, the shaft diameter of the compressor main shaft 5 has shrunk uniformly, and an assembly gap is formed between the all-ceramic bearing and the compressor main shaft 5. The all-ceramic bearing is fixedly installed through the bearing housing 8 by the bearing housing clamp 7, ensuring that the bearing housing 8 and the compressor main shaft 5 remain coaxial. Continue to rotate the drive input shaft 4 and ball screw 3 to move the compressor main shaft 5 downward along the guide rail 2 again, accurately aligning the all-ceramic bearing. Using the assembly gap generated by the shrinkage of the compressor main shaft 5 shaft diameter, the all-ceramic bearing is installed on the compressor main shaft 5, completing the interference fit assembly.

[0024] After assembly, the compressor main shaft 5 returns to room temperature, the shaft diameter springs back, and a firm interference fit is formed with the all-ceramic bearing. This step, through the precise positioning of the bearing housing fixture 7 and the bearing housing 8, and the precise control of the drive mechanism, achieves the precise assembly of the compressor main shaft 5 and the all-ceramic bearing. This solves the problems of low assembly accuracy and poor coaxiality in the existing technology, avoids the risk of mechanical damage to key components such as bearing raceways and cages caused by the traditional press fitting method, and significantly improves the assembly quality and bearing service life.

[0025] like Figure 3 and Figure 4 As shown, a sealing assembly 10 is installed on the top of the liquid nitrogen cooling tank 9, a guide assembly 12 is provided inside the sealing assembly 10, and a sealing assembly 11 is installed on the top inside the sealing assembly 10. The sealing component 10 contacts the sealing component 11 under the action of the guide component 12, and seals the opening at the top of the liquid nitrogen cooling tank 9; The sealing assembly 10 includes a docking frame 101 fixed to the top of the liquid nitrogen cooling tank 9, and a receiving frame 103 is installed on the top of the docking frame 101. The docking frame 101 and the receiving frame 103 are connected to the liquid nitrogen cooling tank 9. The top of the receiving frame 103 is threaded with a cover plate 102.

[0026] The connecting frame 101 is fixedly installed on the top of the liquid nitrogen cooling tank 9, and the receiving frame 103 is installed on the top of the connecting frame 101. The connecting frame 101 and the receiving frame 103 are connected to the inside of the liquid nitrogen cooling tank 9 to form a channel for the compressor main shaft 5 to enter and exit the liquid nitrogen cooling tank 9. The cover plate 102 is threadedly connected to the top of the receiving frame 103 to achieve a seal on the liquid nitrogen cooling tank 9.

[0027] like Figures 5-8 As shown, the guide assembly 12 includes a guide frame 121 installed inside the docking frame 101; The sealing assembly 10 also includes a sealing plate 105, on the top of which a sealing plug 106 is fixedly mounted; The guide frame 121 has a guide groove 104, and the end of the sealing plate 105 slides in the guide groove 104 through the protrusion 108; The sealing plate 105, the sealing plug 106 and the guide assembly 12 are symmetrically installed inside the docking frame 101, and the opposite surfaces of the two sealing plugs 106 are provided with sealing gaskets 107. The guide assembly 12 also includes a fixing plate 122 fixed inside the guide frame 121. A transmission rod 126 is movably sleeved on the fixing plate 122. A sliding groove 127 is opened at the end of the sealing plate 105. The transmission rod 126 slides in the sliding groove 127 through the connecting slide 129. A transmission plate 123 is installed at the top of the transmission rod 126, and an elastic element 124 supporting the transmission plate 123 is provided at the top of the fixing plate 122. A stabilizing rod 128 is movably sleeved at the end of the sealing plate 105, and the stabilizing rod 128 slides within the guide frame 121; The guide groove 104 consists of a vertical end and an inclined end; In the initial state, under the action of the elastic member 124, the sealing plate 105 is located in the vertical end of the guide groove 104 through the protrusion 108, so that the two sealing plugs 106 form a frustum and the two sealing gaskets 107 are in contact, and the frustum is fitted on the bottom of the sealing assembly 11 to achieve sealing. The two sealing plugs 106 form a truncated cone with both the top and bottom recessed.

[0028] In the initial state, the sealing plate 105, under the action of the elastic element 124 and the connecting slide 129, is positioned at the vertical end of the guide groove 104 via the protrusion 108. Two sealing plugs 106 form a frustum fitted onto the bottom of the sealing assembly 11, and two sealing gaskets 107 are in contact. The top and bottom of the frustum formed by the two sealing plugs 106 are both concave, thus sealing the top opening of the liquid nitrogen cooling tank 9. This step, through the supporting action of the elastic element 124, ensures that the sealing plate 105 maintains a stable sealing position, and the frustum formed by the two sealing plugs 106 is fitted onto the bottom of the sealing assembly 11.

[0029] When the compressor main shaft 5 needs to be cooled, it moves down along the guide rail 2, passing through the middle of the receiving frame 103 and the sealing assembly 11, and contacts the top surface of the frustum. As the compressor main shaft 5 continues to move down, it pushes the sealing plate 105 to slide down along the guide groove 104 through the protrusion 108. Since the guide groove 104 is composed of a vertical end and an inclined end, when it moves to the inclined end, the inclined end of the guide groove 104 converts the linear movement of the sealing plate 105 into an outward expansion displacement. The two sealing plates 105 and the sealing plug 106 gradually move towards both ends, allowing the compressor main shaft 5 to pass between the two sealing plugs 106, opening the top opening of the liquid nitrogen cooling tank 9. This step, driven by the thrust of the compressor main shaft 5, drives the guide assembly 12, realizing the automatic opening of the sealing assembly 10 without manual operation, improving the degree of automation, solving the problem of manual opening and closing of the liquid nitrogen tank lid in the prior art, which is cumbersome, and significantly improving the work efficiency.

[0030] As the sealing plate 105 continues to move downwards, it drives the transmission rod 126 to compress the elastic element 124 via the transmission plate 123, and the elastic element 124 stores elastic potential energy. Simultaneously, as the sealing plate 105 slides outwards, it slides along the connecting slide 129 via the slide groove 127, ensuring that the sealing plate 105 and the transmission rod 126 remain in a movable connection, preventing the sealing plate 105 from disengaging from the transmission rod 126 and improving the stability and reliability of the movement. The stabilizing rod 128 slides within the guide frame 121, providing additional stable support for the sealing plate 105, ensuring that the sealing plate 105 remains stable during movement, avoiding swaying and jamming, solving the problems of poor movement stability and easy jamming in the prior art, and improving assembly accuracy and equipment service life.

[0031] After passing between the two sealing plugs 106, the compressor main shaft 5 continues to move downwards into the interior of the liquid nitrogen cooling tank 9 and is immersed in liquid nitrogen for freezing treatment. Because the inclined end of the guide groove 104 acts as a guide and limiter, the movement trajectory and opening / closing degree of the sealing plugs 106 are precisely controlled, ensuring that the sealing plugs 106 can be fully opened, providing sufficient passage space for the compressor main shaft 5. This avoids collisions or jamming of the compressor main shaft 5 during entry and exit, solving the problems of poor control accuracy and easy jamming in the opening and closing process in existing technologies, and improving assembly accuracy and reliability.

[0032] After the compressor main shaft 5 has finished freezing, it moves upward along the guide rail 2 and disengages from the interior of the liquid nitrogen cooling tank 9. As the compressor main shaft 5 leaves, the transmission plate 123 loses the thrust of the compressor main shaft 5, and the elastic element 124 releases its elastic potential energy, pushing the transmission plate 123 upward. This step, through the elastic reset action of the elastic element 124, achieves the automatic reset of the guide assembly 12 without manual intervention, improving the degree of automation, solving the problem of manual sealing required in the prior art, and improving operational efficiency and safety.

[0033] At this time, under the action of the elastic element 124 and the transmission rod 126, the two sealing plates 105 move upward along the guide groove 104 through the protrusion 108. The protrusion 108 slides from the inclined end to the vertical end of the guide groove 104, and the two sealing plates 105 and the sealing plug 106 approach each other, re-forming a truncated cone, and the two sealing gaskets 107 fit together. The truncated cone is fitted onto the bottom of the sealing assembly 11, forming a seal on the liquid nitrogen cooling tank 9. The top and bottom of the truncated cone formed by the two sealing plugs 106 are both concave, which increases the sealing contact area and sealing pressure, and improves the reliability of the seal. This step, through the design of the vertical and inclined ends of the guide groove 104, converts the linear motion of the compressor main shaft 5 into the opening and closing motion of the sealing plug 106, precisely controls the movement trajectory and opening and closing degree of the sealing plug 106, realizes the automatic sealing of the liquid nitrogen cooling tank 9, reduces the evaporation of liquid nitrogen, improves the utilization efficiency of liquid nitrogen, saves costs, and solves the problems of poor sealing performance and serious liquid nitrogen evaporation in the prior art.

[0034] like Figure 5 , Figure 6 and Figure 9 As shown, the sealing assembly 11 includes a metal elastic member 111 fixed inside the receiving frame 103. The metal elastic member 111 is corrugated and its inner diameter gradually increases from top to bottom. A slide 117 is installed at the bottom of the metal elastic member 111 and slides on the bottom of the receiving frame 103. A gasket 113 is mounted on the annular protrusion at the uppermost end of the inner wall of the metal elastic element 111 via a ring array of the first mating member 112; On the lower end of the inner wall of the metal elastic element 111, two annular protrusions are provided with snap-fit ​​members 115 through the second mating member 114 in an annular array, and the inner wall of the snap-fit ​​member 115 is provided with a sealing ring 116. When the sealing plug 106 is assembled into a frustum and fitted onto the lower end of the metal elastic member 111, the outer wall of the frustum contacts the inner wall of the sealing ring 116.

[0035] Initial sealing state: The sealing plug 106 forms a frustum fitted around the bottom of the metal elastic element 111. At this time, the sealing plate 105 pushes the metal elastic element 111 upward under the action of the elastic element 124, causing it to contract. The metal elastic element 111 is corrugated, and after being pushed, the annular protrusions on its inner wall contract and deform inward, causing the snap-fit ​​element 115 and the sealing ring 116 to tighten inward, so that the sealing ring 116 tightly abuts against the outside of the frustum, forming a multi-layer sealing structure. This step, through the elastic deformation of the metal elastic element 111 and the cooperation of the sealing plug 106, significantly improves the sealing effect of the liquid nitrogen cooling tank 9, effectively prevents liquid nitrogen evaporation, and solves the problem of insufficient sealing reliability in the prior art.

[0036] Shaft passage state: The compressor main shaft 5 moves downwards and passes through the interior of the metal elastic element 111. Since the inner diameter of the metal elastic element 111 gradually increases from top to bottom, forming a tapered channel, the compressor main shaft 5 does not contact the sealing ring 116 at the lower end of the inner wall during passage. This avoids the compressor main shaft 5, after freezing, directly contacting the sealing ring 116 at a low temperature, which could lead to hardening, embrittlement, and other aging problems, thus extending the service life of the sealing ring 116. Simultaneously, when the compressor main shaft 5 passes through the upper part of the metal elastic element 111, the gaskets 113 installed in a ring array on the first mating member 112 reduce the gap between the compressor main shaft 5 and the gaskets 113. This minimizes the cross-sectional area of ​​the top opening of the liquid nitrogen cooling tank 9 while ensuring smooth passage of the shaft, reducing the evaporation rate of liquid nitrogen, improving the utilization efficiency of liquid nitrogen, and saving operating costs.

[0037] Sealing restoration state: The compressor main shaft 5 moves upward and disengages from the interior of the metal elastic element 111. The sealing plug 106 reforms into a frustum and fits onto the lower end of the metal elastic element 111. Under the action of the elastic element 124, the sealing plate 105 pushes the metal elastic element 111 upward again to contract, and the sealing ring 116 re-presses tightly against the outside of the frustum, restoring the sealing state. Through the elastic reset performance of the metal elastic element 111, the automatic sealing function of the sealing assembly is realized without manual intervention, ensuring the sealing reliability of the liquid nitrogen cooling tank 9 in the non-operating state.

[0038] Working principle and usage process of this invention: I. Shaft Freezing Stage The compressor spindle 5 is mounted on the shaft clamp 6. Through the precise fit between the vertical frame 1 and the guide rail 2, the shaft clamp 6 drives the compressor spindle 5 to move smoothly and accurately up and down along the guide rail 2. Rotating the drive input shaft 4 and the ball screw 3 drives the compressor spindle 5 to move downward along the guide rail 2, causing the compressor spindle 5 to gradually penetrate into the liquid nitrogen cooling tank 9. Since the opening at the top of the liquid nitrogen cooling tank 9 is coaxial with the compressor spindle 5, the compressor spindle 5 can fully contact the liquid nitrogen. Through the deep cooling effect of the liquid nitrogen, the shaft diameter of the compressor spindle 5 shrinks uniformly. After maintaining this position for a certain period of time to allow the shaft to cool fully, and once the temperature of the compressor spindle 5 stabilizes and it shrinks to the required size, an assembly gap is formed between the all-ceramic bearing and the compressor spindle 5.

[0039] II. Automatic opening and closing stage of the sealing assembly Initial sealing state: Under the action of the elastic element 124, the sealing plate 105 is positioned inside the vertical end of the guide groove 104 via the protrusion 108, and the two sealing plugs 106 form a frustum fitted onto the bottom of the metal elastic element 111. At this time, the sealing plate 105 pushes the metal elastic element 111 upward to contract, causing its inner wall annular protrusions to contract and deform inward, driving the sealing ring 116 to tightly abut against the outside of the frustum, thus sealing the top opening of the liquid nitrogen cooling tank 9.

[0040] Shaft passage state: The compressor main shaft 5 moves downward, passing through the middle of the receiving frame 103 and the sealing assembly 11, and contacts the top surface of the frustum. As the compressor main shaft 5 continues to move downward, it pushes the sealing plate 105 to slide downward along the guide groove 104 through the protrusion 108. Since the guide groove 104 is composed of a vertical end and an inclined end, when it moves to the inclined end, the inclined end of the guide groove 104 converts the linear movement of the sealing plate 105 into an outward expansion displacement. The two sealing plates 105 and the sealing plug 106 gradually move towards both ends, allowing the compressor main shaft 5 to pass between the two sealing plugs 106, opening the top opening of the liquid nitrogen cooling tank 9. When the compressor main shaft 5 passes through the interior of the metal elastic element 111, since the inner diameter of the metal elastic element 111 gradually increases from top to bottom, forming a conical channel, the compressor main shaft 5 does not contact the sealing ring 116 at the lower end of the inner wall, avoiding aging of the sealing ring due to the low temperature shaft. At the same time, the upper gasket 113 reduces the gap with the shaft, reducing liquid nitrogen evaporation.

[0041] Sealing restoration state: After the compressor main shaft 5 moves upward and disengages from the liquid nitrogen cooling tank 9, the transmission plate 123 loses the thrust of the compressor main shaft 5, and the elastic element 124 releases its elastic potential energy to push the transmission plate 123 upward. Under the action of the elastic element 124 and the transmission rod 126, the two sealing plates 105 move upward along the guide groove 104 through the protrusion 108, sliding from the inclined end to the vertical end. The two sealing plugs 106 approach each other and re-form a truncated cone, and the sealing ring 116 tightly abuts against the outside of the truncated cone again, restoring the sealing state.

[0042] III. Bearing Assembly Stage The reverse rotation of the drive input shaft 4 and ball screw 3 causes the compressor main shaft 5 to move upward along the guide rail 2 and be removed from the liquid nitrogen cooling tank 9. At this time, the shaft diameter of the compressor main shaft 5 has uniformly contracted. The all-ceramic bearing is fixedly installed through the bearing housing 8 using the bearing housing clamp 7, ensuring that the bearing housing 8 and the compressor main shaft 5 remain coaxial. The drive input shaft 4 and ball screw 3 are then rotated again, causing the compressor main shaft 5 to move downward along the guide rail 2, precisely aligning with the all-ceramic bearing. Utilizing the assembly clearance created by the contraction of the compressor main shaft 5's shaft diameter, the all-ceramic bearing is installed on the compressor main shaft 5, completing the interference fit assembly. After assembly, the compressor main shaft 5 returns to room temperature, the shaft diameter springs back, and a firm interference fit connection is formed with the all-ceramic bearing.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A full ceramic bearing assembly device suitable for extreme low temperature wind tunnel spindle systems, comprising a vertical frame (1), characterized in that, The vertical frame (1) is equipped with a guide rail (2), and the compressor main shaft (5) is slidably mounted on the guide rail (2) through a shaft clamp (6). The vertical frame (1) is provided with a drive input shaft (4) and a ball screw (3). The drive input shaft (4) is connected to the end of the ball screw (3) through a coupling. When the drive input shaft (4) rotates, the compressor main shaft (5) and its connected shaft clamp (6) are driven to make axial feed motion along the guide rail (2) through the helical transmission action of the ball screw (3); The vertical frame (1) is equipped with a bearing seat fixture (7), and the all-ceramic bearing is installed on the bearing seat fixture (7) through the bearing seat (8), and the bearing seat (8) is coaxial with the compressor main shaft (5); A liquid nitrogen cooling tank (9) is installed on the vertical frame (1), and the compressor main shaft (5) is coaxial with the opening at the top of the liquid nitrogen cooling tank (9); The compressor main shaft (5) is mounted on the shaft clamp (6). The rotating drive input shaft (4) and ball screw (3) cause the compressor main shaft (5) to move downward along the guide rail (2) and extend into the liquid nitrogen cooling tank (9) for freezing. The compressor main shaft (5) moves along the guide rail (2) by rotating the drive input shaft (4) in the opposite direction. The all-ceramic bearing is installed on the bearing seat fixture (7) through the bearing seat (8). Then, the drive input shaft (4) is rotated to move the compressor main shaft (5) down and assemble it with the all-ceramic bearing. A sealing assembly (10) is installed on the top of the liquid nitrogen cooling tank (9). A guide assembly (12) is provided inside the sealing assembly (10). A sealing assembly (11) is installed on the top inside the sealing assembly (10). The sealing component (10) comes into contact with the sealing component (11) under the action of the guide component (12) to seal the opening at the top of the liquid nitrogen cooling tank (9); The sealing assembly (10) includes a docking frame (101) fixed to the top of the liquid nitrogen cooling tank (9), and a receiving frame (103) is installed on the top of the docking frame (101). The docking frame (101) and the receiving frame (103) are connected to the liquid nitrogen cooling tank (9), and the top of the receiving frame (103) is threaded with a cover plate (102). The guide assembly (12) includes a guide frame (121) installed inside the docking frame (101). The sealing assembly (10) further includes a sealing plate (105), on the top of which a sealing plug (106) is fixedly mounted. The guide frame (121) is provided with a guide groove (104), and the end of the sealing plate (105) slides in the guide groove (104) through a protrusion (108); The sealing plate (105), the sealing plug (106) and the guide assembly (12) are symmetrically installed inside the docking frame (101), and the two sealing plugs (106) are provided with sealing gaskets (107) on their opposite sides. The guide assembly (12) further includes a fixing plate (122) fixed inside the guide frame (121), a transmission rod (126) is movably sleeved on the fixing plate (122), and a sliding groove (127) is opened at the end of the sealing plate (105). The transmission rod (126) slides in the sliding groove (127) through the connecting slide (129). A transmission plate (123) is installed at the top of the transmission rod (126), and an elastic element (124) supporting the transmission plate (123) is provided at the top of the fixing plate (122). The end of the sealing plate (105) is movably fitted with a stabilizing rod (128), which slides within the guide frame (121).

2. The all-ceramic bearing assembly device for extreme low-temperature wind tunnel spindle systems according to claim 1, characterized in that: The guide groove (104) is composed of a vertical end and an inclined end; In the initial state, under the action of the elastic member (124), the sealing plate (105) is located in the vertical end of the guide groove (104) through the protrusion (108), so that the two sealing plugs (106) form a frustum and the two sealing gaskets (107) fit together, and the frustum is fitted on the bottom of the sealing assembly (11) to achieve sealing; The top and bottom of the two sealing plugs (106) forming a frustum are both concave.

3. The all-ceramic bearing assembly device for extreme low-temperature wind tunnel spindle systems according to claim 1, characterized in that: The sealing assembly (11) includes a metal elastic element (111) fixed inside the receiving frame (103). The metal elastic element (111) is corrugated and its inner diameter gradually increases from top to bottom. A slide (117) is installed at the bottom of the metal elastic element (111) and slides on the bottom of the receiving frame (103). A gasket (113) is mounted on the annular protrusion at the uppermost end of the inner wall of the metal elastic element (111) through an annular array of the first mating member (112).

4. The all-ceramic bearing assembly device for extreme low-temperature wind tunnel spindle systems according to claim 3, characterized in that: The metal elastic element (111) has two annular protrusions on the lower end of the inner wall with snap-fit ​​members (115) arranged in an annular array through the second docking member (114), and the inner wall of the snap-fit ​​member (115) is provided with a sealing ring (116). When the sealing plug (106) is assembled to form a frustum and fitted onto the lower end of the metal elastic member (111), the outer wall of the frustum contacts the inner wall of the sealing ring (116).

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