Spherical hinge structure of Stirling cryocooler and Stirling cryocooler

Abstract

The spherical hinge structure comprises a connecting assembly and a plugging assembly, the connecting assembly comprises a first connecting piece and a second connecting piece, the plugging assembly comprises a first plugging piece and a second plugging piece, and a sealing ring is arranged in an annular groove of the second connecting piece, so that the sealing ring is arranged in the annular groove of the second connecting piece; the matching sizes of the sealing ring, the groove and the inner wall of the cavity are controlled to form uniform and moderate compression amount, so that local stress concentration is avoided, and the surface friction loss of the sealing ring is greatly reduced. Moreover, a floating gap exists between the plugging assembly and the connecting assembly, so that the sealing ring can automatically adjust the position relation in the moving process, the sealing ring is prevented from bearing too large lateral force, a stable working environment is provided for the sealing ring, and it is ensured that the sealing ring can still maintain reliable sealing performance under the working condition of long-term reciprocating motion.

Description

Technical Field

[0001] This utility model relates to the field of infrared detector technology, and in particular to a Stirling refrigerator ball joint structure and a Stirling refrigerator. Background Technology

[0002] In recent years, with the widespread application of infrared technology in military fields such as infrared imaging, reconnaissance and alarm, early warning and surveillance, guidance, and medium- and high-altitude long-range air defense, as well as in forest fire prevention and gas detection, infrared focal plane detector technology has developed rapidly. In the Dewar cooling system, a key component of the infrared detection system, the cooler plays a crucial role in providing a stable low-temperature environment for the detector. Among these components, the regenerator, as the core functional module of the cooler, largely determines the performance of the entire cooling system through its structural design and operating characteristics.

[0003] Specifically, the push piston and matching cylinder in the regenerator assembly form a precise kinematic pair, ensuring that the heat exchange unit can perform accurate reciprocating motion along the axial direction. During system integration, when the refrigerator is coupled to the Dewar assembly, the heat exchange section needs to be accurately inserted into the Dewar cold finger. Due to the unavoidable accumulation of tolerances during machining and assembly, a slight coaxiality deviation often occurs between the crankcase and the Dewar assembly. Using a traditional rigid connection method, this deviation can easily cause friction between the end of the heat exchange unit and the inner wall of the cold finger, which not only generates additional mechanical losses but also significantly affects the overall operating efficiency of the refrigerator.

[0004] To solve this key technical challenge, modern regenerator components generally adopt a ball joint connection scheme. However, after the existing ball joints are manufactured, there is a non-spherical part. This part causes the deformation of the sealing ring to change periodically during operation. After long-term operation, this accelerates the wear of the sealing ring, resulting in a decrease in sealing performance, which in turn damages the performance indicators of the refrigeration unit and even reduces the overall lifespan of the refrigeration unit. Utility Model Content

[0005] This utility model provides a Stirling refrigerator ball joint structure and a Stirling refrigerator, which are used to solve at least one of the above-mentioned technical problems.

[0006] In a first aspect, this utility model provides a ball joint structure for a Stirling refrigerator, comprising:

[0007] A connecting component, the connecting component including a first connector and a second connector, wherein the first connector and the second connector are fixedly connected;

[0008] A sealing assembly includes a first sealing element and a second sealing element, which together surround a cavity. A second connecting element is located inside the cavity. An annular groove is formed on the outer periphery of the second connecting element, and a sealing ring is provided in the annular groove. One side of the sealing ring abuts against the annular groove, and the other side abuts against the inner wall of the cavity, so as to achieve a seal between the connecting assembly and the sealing assembly.

[0009] In one embodiment, the first connector has a protrusion and a first welding part on the side near the second connector, and the second connector has a recess and a second welding part on the side near the first connector. The protrusion is inserted into the recess, and the first welding part and the second welding part are welded and fixed.

[0010] In one embodiment, a guide portion is further provided on the side of the recess near the first connector.

[0011] In one embodiment, a first abutting surface is provided on the side of the recess away from the first connector, and a second abutting surface is provided on the side of the protrusion near the second connector, wherein the first abutting surface abuts against the second abutting surface.

[0012] In one embodiment, the first sealing member is provided with a coaxial mating shaft and a third welding part on the side near the second sealing member, and the second sealing member is provided with a coaxial mating slot and a fourth welding part on the side near the first sealing member. The coaxial mating shaft is inserted into the coaxial mating slot, and the third welding part and the fourth welding part are welded and fixed.

[0013] In one embodiment, a third abutment surface is provided on the side of the coaxial mating slot away from the first sealing member, and a fourth abutment surface is provided on the side of the coaxial mating shaft close to the second sealing member, and the third abutment surface abuts against the fourth abutment surface.

[0014] In one embodiment, the inner diameter spherical surface of the first sealing member is R1, the inner diameter spherical surface of the second sealing member is R2, and the outer diameter spherical surface of the first sealing member is R3, where R2 = R1 and R3 - R1 ≥ 0.3 mm.

[0015] In one embodiment, the first connector has a first vent hole along a first direction, and the second connector has a second vent hole along the first direction, and the first vent hole and the second vent hole are connected.

[0016] In one embodiment, the first connector has a connecting portion on the side away from the second connector, and the connecting portion has a connecting thread.

[0017] Secondly, this utility model also provides a Stirling refrigerator, including the above-mentioned Stirling refrigerator ball joint structure, and further including a regenerator and a push piston. The second sealing member is provided with a mating surface and a blocking surface. The regenerator is mated and connected to the mating surface and abuts against the blocking surface. The push piston is fixedly connected to the first connecting member.

[0018] Compared with the prior art, the advantages of this utility model are as follows: This application provides a Stirling refrigerator ball joint structure and a Stirling refrigerator. The ball joint structure includes a connecting component and a sealing component. The connecting component includes a first connecting member and a second connecting member, and the sealing component includes a first sealing member and a second sealing member. By setting the sealing ring in the annular groove of the second connecting member, the fit dimensions between the sealing ring and the groove and the inner wall of the cavity are controlled, forming a uniform and moderate compression, thereby avoiding local stress concentration and significantly reducing the frictional loss on the surface of the sealing ring. Furthermore, a floating gap exists between the sealing component and the connecting component, allowing the sealing ring to automatically adjust its position during movement, preventing the sealing ring from bearing excessive lateral force, providing a stable working environment for the sealing ring, and ensuring that the sealing ring maintains reliable sealing performance under long-term reciprocating motion conditions. Attached Figure Description

[0019] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of a Stirling refrigerator ball joint structure provided in some embodiments of this application.

[0021] Figure 2 This is a schematic diagram of the structure of the first connecting member of a Stirling refrigerator ball joint structure provided in some embodiments of this application.

[0022] Figure 3 This is a schematic diagram of the second connecting member of a Stirling refrigerator ball joint structure provided in some embodiments of this application.

[0023] Figure 4 This is a schematic diagram of the structure of the first sealing element of a Stirling refrigerator ball joint structure provided in some embodiments of this application.

[0024] Figure 5 This is a schematic diagram of the second sealing component of a Stirling refrigerator ball joint structure provided in some embodiments of this application.

[0025] Figure label:

[0026] 1. First connector; 11. Protrusion; 12. First welding part; 13. Second abutment surface; 14. First vent hole; 15. Connecting part;

[0027] 2. Second connector; 21. Annular groove; 22. Recessed hole; 23. Second welding part; 24. Guide part; 25. First abutment surface; 26. Second vent hole;

[0028] 3. First sealing component; 31. Coaxial mating shaft; 32. Third welding part; 33. Fourth abutment surface;

[0029] 4. Second sealing component; 41. Coaxial mating slot; 42. Fourth welding part; 43. Third abutment surface; 44. Mating surface; 45. Cut-off surface;

[0030] 5. Sealing ring;

[0031] X, the first direction. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0034] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or a joint; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0036] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0038] The present invention will be further described below with reference to the accompanying drawings.

[0039] Firstly, see Figures 1-5 This application provides a Stirling refrigerator ball joint structure in one embodiment. The ball joint structure includes a connecting component and a sealing component. The connecting component includes a first connecting member 1 and a second connecting member 2, which are fixedly connected. The sealing component includes a first sealing member 3 and a second sealing member 4, which together surround a cavity. The second connecting member 2 is located inside the cavity. An annular groove 21 is formed on the outer periphery of the second connecting member 2. A sealing ring 5 is provided in the annular groove 21. One side of the sealing ring 5 abuts against the annular groove 21, and the other side abuts against the inner wall of the cavity to achieve a seal between the connecting component and the sealing component.

[0040] The Stirling refrigerator ball joint structure provided in this embodiment of the application, by placing the sealing ring 5 in the annular groove 21 of the second connecting member 2, controls the fit dimensions between the sealing ring 5 and the groove and the inner wall of the cavity, forming a uniform and moderate compression amount, thereby avoiding local stress concentration and significantly reducing the surface friction loss of the sealing ring 5. Furthermore, the floating gap between the sealing component and the connecting component allows the sealing ring 5 to automatically adjust its position during movement, preventing the sealing ring 5 from bearing excessive lateral force, providing a stable working environment for the sealing ring 5, and ensuring that the sealing ring 5 maintains reliable sealing performance under long-term reciprocating motion conditions.

[0041] Furthermore, the stable transmission of the mechanical structure is achieved through the fixed connection between the first connector 1 and the second connector 2, while the cavity structure formed by the first sealing member 3 and the second sealing member 4 provides encapsulation and protection for the second connector 2. The annular groove 21 on the outer periphery of the second connector 2 and the sealing ring 5 therein achieve a reliable seal between the connecting assembly and the sealing assembly. One side of the sealing ring 5 tightly abuts against the annular groove 21, and the other side fully contacts the inner wall of the cavity, effectively preventing media leakage. This ball joint structure ensures the mechanical strength of the connecting part 15 and compensates for assembly tolerances through the elastic deformation of the sealing ring 5, ensuring long-term sealing performance under complex working conditions. It also simplifies the assembly process and improves the overall structural reliability.

[0042] like Figures 1-3 As shown, in some embodiments, the first connector 1 is provided with a protrusion 11 and a first welding part 12 on the side near the second connector 2, and the second connector 2 is provided with a recess 22 and a second welding part 23 on the side near the first connector 1. The protrusion 11 is inserted into the recess 22, and the first welding part 12 and the second welding part 23 are welded and fixed.

[0043] The precise insertion of the protrusion 11 into the recess 22 achieves accurate positioning of the first connector 1 and the second connector 2, ensuring their coaxiality. At the same time, the reliable welding of the first welding part 12 and the second welding part 23 forms a strong mechanical connection. This structural design ensures the assembly accuracy of the connecting components and provides sufficient connection strength, so that the overall structure remains stable when bearing loads.

[0044] In addition, the welding method avoids the risk of loosening that may occur with threaded connections. The fit between the protrusion 11 and the concave hole 22 provides a precise positioning reference for the welding process, ensuring the consistency of welding quality, simplifying the assembly process, and greatly improving production efficiency.

[0045] like Figures 1-3 As shown, in some embodiments, a guide portion 24 is also provided on the side of the recess 22 near the first connector 1.

[0046] By providing a guide portion 24 on the side of the recess 22 near the first connector 1, precise guidance and smooth alignment of the protruding part 11 during insertion are achieved. The guide portion 24 is designed with a sloped or arc-shaped transition structure, which can effectively guide the protruding part 11 smoothly into the recess 22, avoiding possible jamming or misalignment during assembly. By providing a sloped or arc-shaped transition structure, the assembly efficiency and fitting accuracy of the first connector 1 and the second connector 2 can be significantly improved, ensuring accurate alignment of the welded parts and providing a reliable positioning reference for subsequent welding processes.

[0047] like Figures 1-3 As shown, in some embodiments, a first abutting surface 25 is provided on the side of the recess 22 away from the first connector 1, and a second abutting surface 13 is provided on the side of the protrusion 11 near the second connector 2, and the first abutting surface 25 abuts against the second abutting surface 13.

[0048] The engagement of the first abutment surface 25 and the second abutment surface 13 enables precise control over the insertion depth of the protrusion 11, thereby ensuring the assembly consistency of the connecting components. Furthermore, the engagement of the first abutment surface 25 and the second abutment surface 13 provides a stable positioning reference for the welding process, ensuring consistent welding quality. It also enhances the load-bearing capacity of the connecting components under axial loads, further improving the overall structural stability and enabling the connecting components to meet the strength requirements for long-term use.

[0049] like Figure 1 , Figure 4 and Figure 5 As shown, in some embodiments, the first sealing member 3 is provided with a coaxial mating shaft 31 and a third welding part 32 on the side near the second sealing member 4, and the second sealing member 4 is provided with a coaxial mating slot 41 and a fourth welding part 42 on the side near the first sealing member 3. The coaxial mating shaft 31 is inserted into the coaxial mating slot 41, and the third welding part 32 and the fourth welding part 42 are welded and fixed.

[0050] The automatic alignment and positioning of the first sealing component 3 and the second sealing component 4 are achieved through the engagement of the coaxial shaft 31 and the coaxial slot 41, ensuring coaxiality during assembly. Simultaneously, the reliable welding of the third welding part 32 and the fourth welding part 42 forms a robust sealing connection, ensuring the assembly accuracy of the sealing assembly and creating a sealed space within the cavity. This welding fixation achieves a sealed connection, preventing the risk of leakage due to loosening during use. Furthermore, the coaxial fit structure provides a precise positioning reference for the welding process, ensuring consistent welding quality and enabling the sealing assembly to withstand higher internal pressures, meeting the reliability requirements for long-term sealing.

[0051] like Figure 1 , Figure 4 and Figure 5 As shown, in some embodiments, a third abutment surface 43 is provided on the side of the coaxial mating slot 41 away from the first sealing member 3, and a fourth abutment surface 33 is provided on the side of the coaxial mating shaft 31 close to the second sealing member 4, and the third abutment surface 43 abuts against the fourth abutment surface 33.

[0052] The engagement of the third abutment surface 43 and the fourth abutment surface 33 enables precise control of the insertion depth of the coaxially mating shaft 31, ensuring the axial positioning accuracy of the sealing assembly. Furthermore, the engagement of these abutment surfaces effectively guarantees the surface profile of the spherical surface formed within the sealing assembly's inner cavity, ensuring smooth movement of the spherical joint during operation and preventing uneven stress on the embedded sealing ring. The engagement of the third abutment surface 43 and the fourth abutment surface 33 achieves radial positioning through coaxial engagement and axial positioning through the abutment surfaces, providing a stable assembly reference for the welding process and ensuring consistent welding quality. In addition, the engagement of the abutment surfaces enhances the axial load-bearing capacity of the sealing assembly under pressure conditions, enabling the sealing structure to maintain stable sealing performance over a long period.

[0053] like Figure 1 , Figure 4 and Figure 5 As shown, in some embodiments, the inner diameter spherical surface of the first sealing element 3 is R1, the inner diameter spherical surface of the second sealing element 4 is R2, the outer diameter spherical surface of the first sealing element 3 is R3, R2=R1, and R3-R1≥0.3mm.

[0054] The precise fit between the inner spherical surface R1 of the first sealing component 3 and the inner spherical surface R2 of the second sealing component 4 ensures the centering accuracy and rotational flexibility during movement. At the same time, by setting the dimensional difference between the outer spherical surface R3 and the inner spherical surface R1 of the first sealing component 3, the ball joint structure is guaranteed to have sufficient wall thickness strength, thereby meeting the precision requirements of the spherical fit and enabling the ball joint to achieve smooth micro-rotation. Furthermore, the reasonable wall thickness design ensures the reliability of the structure in long-term reciprocating motion, avoiding deformation or failure due to insufficient strength, and thus further maintaining stable sealing performance.

[0055] like Figures 1-3 As shown, in some embodiments, a first vent hole 14 is provided in the first connector 1 along the first direction X, and a second vent hole 26 is provided in the second connector 2 along the first direction X. The first vent hole 14 and the second vent hole 26 are connected.

[0056] By providing a first vent hole 14 and a second vent hole 26 that are interconnected within the first connector 1 and the second connector 2, the air pressure inside and outside the connecting components is balanced, ensuring that the cooling air path inside the Stirling refrigerator remains unobstructed at all times.

[0057] In this embodiment of the application, the first direction X is the axial direction of the first connector 1 and the second connector 2.

[0058] like Figures 1-3 As shown, in some embodiments, the first connector 1 is provided with a connecting portion 15 on the side away from the second connector 2, and the connecting portion 15 is provided with connecting threads.

[0059] By providing a threaded connection portion 15 at the end of the connector, the component can be quickly installed and reliably secured to external equipment. The threaded connection structure provides a more convenient detachable assembly method while ensuring that the connection portion 15 has sufficient tensile strength and sealing performance.

[0060] Secondly, see Figure 1 , Figure 4 and Figure 5 An embodiment of this application also provides a Stirling refrigerator, including the above-described Stirling refrigerator ball joint structure, and further including a regenerator and a push piston. The second sealing member 4 is provided with a mating surface 44 and a blocking surface 45. The regenerator is mated and connected to the mating surface 44 and abuts against the blocking surface 45. The push piston is fixedly connected to the first connecting member 1.

[0061] This application provides a Stirling refrigerator that achieves flexible connection and precise force transmission between the regenerator and the push piston by setting a ball joint structure between them. The design of the mating surface 44 and the stop surface 45 in the ball joint structure ensures stable axial positioning of the regenerator, while allowing for slight angle adjustments to compensate for assembly deviations. The rigid fixation of the first connecting piece 1 at the other end to the push piston ensures efficient power transmission. By adopting a ball joint connection method, the mechanical linkage reliability between the core components of the refrigerator is maintained, and the self-aligning function of the ball joint effectively avoids frictional interference between the regenerator and the inner wall of the cold finger, allowing the refrigerator to maintain optimal performance during long-term operation. The overall structure can significantly reduce the assembly process difficulty while ensuring airtightness.

[0062] Although the present invention has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A Stirling refrigerator ball joint structure, characterized in that, include: A connecting component, the connecting component including a first connector and a second connector, wherein the first connector and the second connector are fixedly connected; A sealing assembly includes a first sealing element and a second sealing element, which together surround a cavity. A second connecting element is located inside the cavity. An annular groove is formed on the outer periphery of the second connecting element, and a sealing ring is provided in the annular groove. One side of the sealing ring abuts against the annular groove, and the other side abuts against the inner wall of the cavity, so as to achieve a seal between the connecting assembly and the sealing assembly.

2. The ball joint structure according to claim 1, characterized in that, The first connector has a protrusion and a first welding part on the side near the second connector. The second connector has a recess and a second welding part on the side near the first connector. The protrusion is inserted into the recess, and the first welding part and the second welding part are welded together.

3. The ball joint structure according to claim 2, characterized in that, A guide portion is also provided on the side of the recess near the first connector.

4. The ball joint structure according to claim 2, characterized in that, The recessed hole has a first abutting surface on the side away from the first connector, and the protruding part has a second abutting surface on the side near the second connector, and the first abutting surface abuts against the second abutting surface.

5. The ball joint structure according to claim 1, characterized in that, The first sealing member has a coaxial mating shaft and a third welding part on the side near the second sealing member, and the second sealing member has a coaxial mating slot and a fourth welding part on the side near the first sealing member. The coaxial mating shaft is inserted into the coaxial mating slot, and the third welding part and the fourth welding part are welded and fixed.

6. The ball joint structure according to claim 5, characterized in that, A third abutment surface is provided on the side of the coaxial mating slot away from the first sealing member, and a fourth abutment surface is provided on the side of the coaxial mating shaft close to the second sealing member, and the third abutment surface abuts against the fourth abutment surface.

7. The ball joint structure according to claim 1, characterized in that, The inner diameter spherical surface of the first sealing component is R1, the inner diameter spherical surface of the second sealing component is R2, and the outer diameter spherical surface of the first sealing component is R3, where R2=R1 and R3-R1≥0.3mm.

8. The ball joint structure according to claim 1, characterized in that, The first connector has a first vent hole along the first direction, and the second connector has a second vent hole along the first direction. The first vent hole and the second vent hole are connected.

9. The ball joint structure according to claim 1, characterized in that, The first connector has a connecting portion on the side away from the second connector, and the connecting portion has a connecting thread.

10. A Stirling refrigerator, characterized in that, The device includes the Stirling refrigerator ball joint structure as described in any one of claims 1-9, and further includes a regenerator and a pusher piston. The second sealing member is provided with a mating surface and a blocking surface. The regenerator is mated to the mating surface and abuts against the blocking surface. The pusher piston is fixedly connected to the first connecting member.

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