A room temperature piston type stirling pulse tube cryocooler

Abstract

The application discloses a room-temperature piston type Stirling pulse tube refrigerator and relates to the field of low-temperature refrigeration, comprising a compressor, a separate pipe, a connecting pipe and a pulse tube cold finger; the compressor comprises a center connecting structure, two groups of compressor heat exchangers oppositely distributed on the two sides of the center connecting structure, a linear compression mechanism, a driving motor and an elastic supporting mechanism; the compressor is connected with the pulse tube cold finger through the separate pipe and the connecting pipe respectively. The application has the advantages that the room-temperature piston work recovery technology is adopted to recover the pulse tube heat end expansion work, the overall machine efficiency is improved, the phase of the mass flow and the pressure of the working medium can be adjusted, the optimal matching of the compressor and the pulse tube cold finger is realized, the high-efficiency operation of the overall machine is realized, and the overall machine refrigeration efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of cryogenic refrigeration, and more particularly to a room temperature piston-type Stirling pulse tube refrigerator. Background Technology

[0002] In future space-related high-precision imaging missions characterized by large apertures and high resolution, there will be higher requirements for the cooling efficiency, size, weight, and power consumption of detector payloads. In particular, there are stringent requirements for cryogenic refrigerators, including long lifespan, low vibration interference, and large cooling capacity.

[0003] To meet the application requirements of infrared cameras, ultra-large linear and area array infrared focal plane array devices have been gradually developed: ultra-long linear mid-wave / long-wave 15,000 RMB TDI infrared focal plane array devices, ultra-large area array long-wave 4K×4K infrared focal plane array devices, and ultra-large area array short-wave / mid-wave 6K×6K infrared focal plane array devices, etc. Long linear and large area array infrared detectors require simultaneous cooling of the focal plane and lens (due to their large heat capacity) to suppress their own background noise, thereby further improving the signal-to-noise ratio of optical detection and achieving high detection sensitivity and accuracy, as well as low-noise infrared detection. The development of detectors places demands on the cooling capacity, lifespan, and vibration control of the cooling system.

[0004] Currently, the cryogenic refrigerators in the domestic infrared and optical remote sensing fields are mainly Stirling and Stirling pulse tube refrigerators, such as the Stirling refrigerator disclosed in the patent document with publication number CN113819672A. The existing Stirling refrigerators have the following disadvantages: (1) The cold finger vibration is large, which cannot meet the vibration index requirements of the detector for the cold finger; (2) Traditional pulse tubes use inertial tubes and gas reservoirs for phase adjustment, which has insufficient phase adjustment capability and cannot recover the expansion work of the hot end of the pulse tube, resulting in low cooling efficiency and high power consumption, which cannot meet the current infrared field's requirements for large cooling capacity, high efficiency and low power consumption; (3) The piston is mostly supported by leaf springs inside the compressor, which has limitations such as complex cooling system, large size and weight, and low efficiency. At the same time, the life of the whole machine is limited by the life of the leaf springs, which cannot meet the engineering requirements of the aerospace field.

[0005] Existing cryogenic refrigerators have constrained the development of high-resolution, large-aperture space detector imaging technology, thus affecting my country's progress and development in infrared detection across military, civilian, and aerospace fields. Therefore, to solve the cooling problems of the focal plane and lens of high-resolution, large-aperture space detectors, it is urgent to develop technologies that meet the application needs of future space exploration and other fields. Summary of the Invention

[0006] The technical problem to be solved by this invention is how to improve the refrigeration efficiency of a refrigerator and reduce the vibration of the whole machine.

[0007] The present invention solves the above-mentioned technical problems through the following technical means: a room temperature piston-type Stirling pulse tube refrigerator, comprising a compressor, a distribution pipe, a connecting pipe and a pulse tube refrigeration finger;

[0008] The compressor includes a central connecting structure and two sets of compressor heat exchangers, a linear compression mechanism, a drive motor, and an elastic support mechanism, which are oppositely distributed on both sides of the central connecting structure.

[0009] The linear compression mechanism includes a compressor cylinder, a compression piston, a room temperature piston, a first compression chamber, and a second compression chamber. The room temperature piston is coaxially nested inside the compression piston and is movably engaged with the compression piston. The cavity between the compression piston and the room temperature piston is the first compression chamber, and the cavity between the room temperature pistons of the two sets of linear compression mechanisms is the second compression chamber.

[0010] The drive motor is used to drive the compression piston to reciprocate axially within the compressor cylinder, and the elastic support mechanism is used to provide elastic support for the end of the room temperature piston.

[0011] One end of the split tube is connected to the air inlet of the pulse tube cold finger, and the other end of the split tube is connected to the two first compression chambers through the central connection structure and the two compressor heat exchangers;

[0012] One end of the connecting pipe is connected to the air outlet of the pulse cold finger, and the other end of the connecting pipe is connected to the second compression chamber through the central connecting structure.

[0013] This invention employs room-temperature piston work recovery technology to recover the expansion work at the hot end of the pulse tube, improving overall machine efficiency. By adjusting the weight and diameter of the room-temperature piston, the stiffness of the elastic support mechanism, and the diameter and length of the connecting pipe, the phase of the working fluid's mass flow and pressure can be adjusted to the optimal angle, achieving adjustable phase of the working fluid's mass flow and pressure. This enables optimal matching between the compressor and the pulse tube cold finger, achieving efficient operation of the entire machine and improving overall refrigeration efficiency. The two linear compression mechanisms are arranged opposite each other to cancel out vibrations, reducing compressor vibration output. The compressor and pulse tube cold finger adopt a separate structure, reducing mutual interference between their vibrations. The room-temperature piston replaces the traditional gas reservoir-inertial tube phase adjustment mechanism, and the room-temperature piston is coupled and embedded inside the compressor, achieving miniaturization and weight reduction of the pulse tube cold finger.

[0014] As an optimized technical solution, both the compression piston and the room temperature piston are supported within the compressor cylinder by air-bearing bearings. This invention employs a wear-free, all-air-bearing support technology, resulting in a long service life, small size, and light weight.

[0015] As an optimized technical solution, the compression piston includes an outer compression piston layer, an inner compression piston layer, an inner compression piston bore, a compression piston inlet, a compression piston gas reservoir, a compression piston one-way valve, a compression piston airflow channel, a compression piston outlet, and a balancing gas groove. The inner compression piston layer is fixedly connected inside the outer compression piston layer. The inner compression piston layer is provided with multiple compression piston gas reservoirs. The compression piston inlet extends from the end face of the inner compression piston layer toward the first compression chamber to one of the compression piston gas reservoirs, and the compression piston one-way valve is provided in the compression piston gas reservoir. The outer periphery of the outer compression piston layer is provided with multiple compression piston outlets, and a compression piston airflow channel connects each compression piston gas reservoir and the compression piston outlet. Two balancing gas grooves are symmetrically arranged and extend from both ends of the outer compression piston layer to the outer surface of the outer compression piston layer.

[0016] As an optimized technical solution, the room temperature piston includes a room temperature piston outer layer, a room temperature piston inner layer, a room temperature piston inlet, a room temperature piston gas reservoir, a room temperature piston one-way valve, a room temperature piston airflow channel, and a room temperature piston outlet. The room temperature piston inner layer is fixedly connected inside the room temperature piston outer layer. The room temperature piston inner layer is provided with a room temperature piston gas reservoir. The room temperature piston inlet extends axially from the end face of the room temperature piston inner layer toward the second compression chamber to the room temperature piston gas reservoir. The room temperature piston one-way valve is provided in the room temperature piston gas reservoir. The outer periphery of the room temperature piston outer layer is provided with multiple room temperature piston outlets. The room temperature piston gas reservoir and the room temperature piston outlets are connected by a room temperature piston airflow channel.

[0017] As an optimized technical solution, the central connection structure includes a cylinder mounting cylinder, a central flange, an annular groove, an axial straight hole, a first radial hole, a second radial hole, and a vent hole. The central flange is fixedly connected to the middle position of the outer periphery of the cylinder mounting cylinder. The two end faces of the central flange are symmetrically provided with annular grooves surrounding the outer periphery of the cylinder mounting cylinder. The annular grooves are separated from the inner hole of the cylinder mounting cylinder by the side wall of the cylinder mounting cylinder. The first radial hole extends from the outer side of the central flange to the outer side of the cylinder mounting cylinder. The axial straight hole penetrates the bottom surface of the two annular grooves and connects to the first radial hole. The distribution pipe connects to the first radial hole. Multiple through holes are evenly distributed circumferentially on the compressor cylinder. The distribution pipe connects to the two first compression chambers sequentially through the first radial hole, the axial straight hole, the two annular grooves, the two compressor heat exchangers, and the through holes on the two compressor cylinders.

[0018] The second radial hole extends from the outer side of the central flange to the outer side of the cylinder mounting cylinder. The vent hole penetrates the side wall of the cylinder mounting cylinder and communicates with the second radial hole. The connecting pipe is connected to the second radial hole. The connecting pipe communicates with the second compression chamber in sequence through the second radial hole and the vent hole.

[0019] As an optimized technical solution, the drive motor includes an inner stator, an outer stator, and a permanent magnet assembly. The inner stator, permanent magnet assembly, and outer stator are coaxially arranged from the inside to the outside of the compressor cylinder. The inner stator and the outer stator are fixedly disposed relative to the compressor cylinder, and the permanent magnet assembly is movably disposed in the annular magnetic gap between the inner stator and the outer stator and fixedly connected to the compression piston. The outer stator is located in a sealed cavity independent of the compressor cylinder. The drive motor adopts an externally mounted moving magnet winding type, and the outer stator is independent of the working fluid, avoiding the outgassing of non-metallic materials such as the windings on the outer stator that could cause working fluid contamination, thus improving the reliability and lifespan of the compressor.

[0020] As an optimized technical solution, the permanent magnet assembly includes main permanent magnets and auxiliary permanent magnets. Multiple main permanent magnets are arranged in a ring and uniformly distributed in pairs. Auxiliary permanent magnets are symmetrically arranged at both ends of the axial direction of each main permanent magnet. Both the main and auxiliary permanent magnets are radially magnetized with opposite magnetic polarities. The restoring force generated between the inner and outer stators by the multi-segment magnets composed of the main and auxiliary permanent magnets can automatically drive the permanent magnet assembly to the equilibrium position of the drive motor, achieving self-centering. This multi-segment magnet can limit the axial reciprocating stroke of the compression piston, effectively avoiding drive motor start-up failure caused by the compression piston exceeding its stroke and impacting the compressor cylinder or elastic support mechanism due to an unknown piston position. It avoids complex free piston start-up control procedures, achieving efficient and reliable start-up of the drive motor under complex and harsh conditions. Simultaneously, the self-centering restoring force ensures the consistency of phase and amplitude during normal operation of the refrigeration unit, effectively reducing the residual force of the opposed motor and achieving low vibration output. This multi-segment magnet increases the thrust coefficient of the motor, enabling the drive motor to obtain large thrust under small volume conditions.

[0021] As an optimized technical solution, the pulse tube cold finger includes a pulse tube hot end seat, a hot end heat exchanger, a cold finger cylinder, a cold head, a pulse tube, a rectifier wire mesh, and a regenerator. The hot end heat exchanger and the cold head are respectively disposed at the hot end and cold end of the cold finger cylinder. The pulse tube hot end seat is disposed on the hot end heat exchanger. The pulse tube is coaxially arranged inside the cold finger cylinder. The hot end of the pulse tube is isolated from the hot end heat exchanger, and the cold end of the pulse tube is connected to the cold head. The pulse tube hot end seat is provided with an outlet connecting to the pulse tube, and the hot end heat exchanger is provided with an inlet connecting to the cold finger cylinder. Rectifier wire meshes are respectively disposed at the hot end and cold end of the pulse tube. The regenerator is filled in the annular cavity between the cold finger cylinder and the pulse tube.

[0022] As an optimized technical solution, the regenerator is a ring-shaped structure made of wire mesh. The main body of the regenerator adopts a segmented mixed filling form from the hot end to the cold end, consisting of woven wire mesh and sintered wire mesh. Woven wire mesh is arranged on the outer side of the hot end and the outer side of the cold end of the main body of the regenerator. The porosity of the regenerator can be adjusted by adjusting the weight ratio of woven wire mesh to sintered wire mesh, achieving adjustable porosity, ensuring that the specific heat capacity and specific surface area of ​​the regenerator meet the requirements, and reducing axial heat conduction loss and pressure drop loss.

[0023] As an optimized technical solution, the elastic support mechanism includes a leaf spring, which comprises a leaf spring body, an inner mounting hole, an outer mounting hole, an inner profile, an outer profile, a head, and a tail. The leaf spring body has an inner mounting hole at its center for connecting to the room temperature piston, and multiple outer mounting holes on its outer edge for fixing the leaf spring body. Multiple circumferentially evenly distributed curved holes are located on the leaf spring body between the inner and outer mounting holes. These curved holes are formed by multiple smooth arc transitions from the inner profile, outer profile, head, and tail to create closed curves. The stiffness of the leaf spring can be adjusted by changing the length and distance of the inner and outer profiles, and the stress concentration of the leaf spring can be reduced by adjusting the arc shape of the head and tail, thereby meeting the requirements for long service life.

[0024] The advantages of this invention are:

[0025] 1. This invention employs room temperature piston work recovery technology to recover the expansion work at the hot end of the pulse tube, improving overall machine efficiency. By adjusting the weight and diameter of the room temperature piston, the stiffness of the elastic support mechanism, the diameter and length of the connecting pipe, the phase of the working fluid's mass flow and pressure can be adjusted to the optimal angle, achieving adjustable phase of the working fluid's mass flow and pressure. This enables optimal matching between the compressor and the pulse tube cold finger, achieving efficient operation of the entire machine and improving overall refrigeration efficiency. The two linear compression mechanisms are arranged opposite each other to cancel out vibrations, reducing compressor vibration output. The compressor and pulse tube cold finger adopt a separate structure, reducing mutual interference between their vibrations. The room temperature piston replaces the traditional gas reservoir-inertial tube phase adjustment mechanism, and the room temperature piston is coupled and embedded inside the compressor, achieving miniaturization and weight reduction of the pulse tube cold finger.

[0026] 2. This invention adopts a wear-free support technology with full air-bearing bearings, that is, both the compression piston and the room temperature piston are supported by air-bearing bearings in the compressor cylinder, resulting in long service life, small size, and light weight.

[0027] 3. The restoring force generated between the inner and outer stators by the multi-segment magnets composed of the main permanent magnet and the auxiliary permanent magnet can automatically drive the permanent magnet assembly to the balance position of the drive motor, achieving self-centering. This multi-segment magnet can limit the axial reciprocating stroke of the compression piston, effectively avoiding drive motor start-up failure caused by the compression piston exceeding its stroke due to an unknown position, impacting the compressor cylinder or elastic support mechanism. It also avoids complex free piston start-up control procedures, achieving efficient and reliable start-up of the drive motor under complex and harsh conditions. At the same time, the self-centering restoring force can ensure the consistency of phase and amplitude during the normal operation of the refrigeration unit, effectively reducing the residual force of the opposed motor and achieving low vibration output. This multi-segment magnet increases the thrust coefficient of the motor, enabling the drive motor to obtain large thrust under small volume conditions. Attached Figure Description

[0028] Figure 1 This is a cross-sectional schematic diagram of the room temperature piston-type Stirling pulse tube refrigerator according to Embodiment 1 of the present invention.

[0029] Figure 2 This is an isometric schematic diagram of the central connection structure according to Embodiment 1 of the present invention.

[0030] Figure 3 This is a schematic diagram of the AA cross-section of the central connection structure in Embodiment 1 of the present invention.

[0031] Figure 4 This is an isometric schematic diagram of the compressor heat exchanger according to Embodiment 1 of the present invention.

[0032] Figure 5 This is a cross-sectional schematic diagram of the compressor cylinder according to Embodiment 1 of the present invention.

[0033] Figure 6 This is a cross-sectional schematic diagram of the compression piston according to Embodiment 1 of the present invention.

[0034] Figure 7 This is a cross-sectional schematic diagram of the room temperature piston according to Embodiment 1 of the present invention.

[0035] Figure 8 This is a cross-sectional schematic diagram of the inner stator in Embodiment 1 of the present invention.

[0036] Figure 9 This is a cross-sectional schematic diagram of the outer stator in Embodiment 1 of the present invention.

[0037] Figure 10 This is a cross-sectional schematic diagram of the permanent magnet component according to Embodiment 1 of the present invention.

[0038] Figure 11 This is a top view schematic diagram of the main permanent magnet in Embodiment 1 of the present invention.

[0039] Figure 12 This is a top view schematic diagram of the auxiliary permanent magnet in Embodiment 1 of the present invention.

[0040] Figure 13 This is a top view schematic diagram of a leaf spring according to Embodiment 1 of the present invention.

[0041] Figure 14 This is an isometric schematic diagram of the hot-end heat exchanger according to Embodiment 1 of the present invention.

[0042] Figure 15 This is an isometric schematic diagram of the cold head according to Embodiment 1 of the present invention.

[0043] Figure 16 This is a cross-sectional schematic diagram of the cold head according to Embodiment 1 of the present invention.

[0044] Figure 17 This is a cross-sectional schematic diagram of the compressor cylinder in Embodiment 2 of the present invention.

[0045] Figure 18 This is a cross-sectional schematic diagram of the permanent magnet component in Embodiment 3 of the present invention.

[0046] In the picture:

[0047] 1. Compressor;

[0048] 101. Center connection structure; 1011. Cylinder mounting sleeve; 1012. Center flange; 1013. Annular air groove; 1014. Axial straight hole; 1015. First radial hole; 1016. Second radial hole; 1017. Vent hole; 1018. Weight reduction hole;

[0049] 102. Compressor heat exchanger; 1021. Compressor heat exchanger base; 1022. Compressor heat exchanger fins;

[0050] 103. Compressor cylinder; 1031. Cylinder body; 1032. Cylinder flange; 1033. Through hole; 1034. Protruding structure; 1035. Cylinder big end; 1036. Cylinder small end;

[0051] 104. Compression piston; 1041. Outer layer of compression piston; 1042. Inner layer of compression piston; 1043. Inner bore of compression piston; 1044. Air inlet of compression piston; 1045. Air reservoir of compression piston; 1046. One-way valve of compression piston; 1047. Air flow channel of compression piston; 1048. Air outlet of compression piston; 1049. Balance air groove;

[0052] 105. Room temperature piston; 1051. Room temperature piston rod; 1052. Room temperature piston outer layer; 1053. Room temperature piston inner layer; 1054. Room temperature piston air inlet; 1055. Room temperature piston air reservoir; 1056. Room temperature piston check valve; 1057. Room temperature piston airflow channel; 1058. Room temperature piston air outlet;

[0053] 106. First compression chamber;

[0054] 107. Second compression chamber;

[0055] 108. Inner stator; 1081. Inner stator ring; 1082. Snap ring;

[0056] 109. Outer stator; 1091. Outer stator block; 1092. Winding frame; 1093. Circular winding; 1094. Pole shoe;

[0057] 110. Permanent magnet assembly; 1101. Permanent magnet frame; 1102. Main permanent magnet; 1103. Auxiliary permanent magnet;

[0058] 111. Support cylinder;

[0059] 112. Outer shell;

[0060] 113. Leaf spring bracket;

[0061] 114. Leaf spring; 1141. Leaf spring body; 1142. Inner mounting hole; 1143. Outer mounting hole; 1144. Inner profile; 1145. Outer profile; 1146. Head; 1147. Tail;

[0062] 115. First screw;

[0063] 116. The second screw;

[0064] 117. End cap;

[0065] 2. Separate placement pipes;

[0066] 3. Connecting pipe;

[0067] 4. Cold fingers;

[0068] 41. Pulse vessel heating end; 411. Pulse vessel mounting hole; 412. Air outlet;

[0069] 42. Hot-end heat exchanger; 421. Air inlet; 422. Hot-end heat exchanger base; 423. Hot-end heat exchanger fins;

[0070] 43. Cold-finger cylinder;

[0071] 44. Cold head; 441. Cold cap; 442. Cold end heat exchanger fins;

[0072] 45. Blood vessels;

[0073] 46. ​​Rectifying wire mesh;

[0074] 47. Regenerator. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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 protection scope of the present invention.

[0076] Example 1

[0077] like Figure 1 As shown, this embodiment discloses a room temperature piston-type Stirling pulse tube refrigerator, including a compressor 1, a split pipe 2, a connecting pipe 3, and a pulse tube cooling finger 4.

[0078] The compressor 1 is connected to the pulse tube cooling finger 4 through the distribution pipe 2 and the connecting pipe 3 respectively. The compressor 1 and the pulse tube cooling finger 4 are filled with a working fluid, which is high-purity helium.

[0079] Compressor 1 is a structure of two free piston linear compressors facing each other, including a central connecting structure 101 and two sets of compressor heat exchangers 102 facing each other on both sides of the central connecting structure 101, a linear compression mechanism, a drive motor, a sealing mechanism, an elastic support mechanism and an end cover 117.

[0080] The linear compression mechanism includes a compressor cylinder 103, a compression piston 104, and a room temperature piston 105. The room temperature piston 105 is coaxially nested inside the compression piston 104 and moves in cooperation with the compression piston 104. Gap seals are formed between the compression piston 104 and the compressor cylinder 103, between the room temperature piston 105 and the compressor cylinder 103, and between the compression piston 104 and the room temperature piston 105. The cavity between the compression piston 104 and the room temperature piston 105 is the first compression chamber 106, and the cavity between the room temperature pistons 105 of the two sets of linear compression mechanisms is the second compression chamber 107.

[0081] The drive motor is used to drive the compression piston 104 to reciprocate axially within the compressor cylinder 103. The drive motor is an externally mounted moving magnet type drive motor, including an inner stator 108, an outer stator 109, and a permanent magnet assembly 110. The inner stator 108, the permanent magnet assembly 110, and the outer stator 109 are coaxially arranged from the inside to the outside of the compressor cylinder 103. The inner stator 108 and the outer stator 109 are fixedly disposed relative to the compressor cylinder 103, and the permanent magnet assembly 110 is movably disposed in the annular magnetic gap between the inner stator 108 and the outer stator 109 and is fixedly connected to the compression piston 104. When the outer stator 109 is energized by alternating current, the annular magnetic gap between the inner stator 108 and the outer stator 109 generates an alternating magnetic field, which drives the permanent magnet assembly 110 to reciprocate axially within the alternating magnetic field, thereby driving the connected compression piston 104 to reciprocate axially, and thus driving the working fluid to generate pressure waves with alternating high and low pressures.

[0082] The sealing mechanism includes a support cylinder 111, a housing 112, and a leaf spring bracket 113. The cylinder body of the support cylinder 111 surrounds the compressor cylinder 103, and the bottom flange of the support cylinder 111 is welded to the compressor cylinder 103. The housing 112 surrounds the support cylinder 111 and is welded to the bottom flange of the support cylinder 111. The leaf spring bracket 113 is located at the opening end of the annular cavity formed by the support cylinder 111 and the housing 112 and is welded to both the support cylinder 111 and the housing 112. A sealed cavity independent of the compressor cylinder 103 is formed between the three components; the inner stator 108 is fixedly connected to the outer periphery of the compressor cylinder 103, the permanent magnet assembly 110 is disposed between the inner stator 108 and the inner wall of the support cylinder 111, and the outer stator 109 is fixedly connected to the outer periphery of the support cylinder 111. This realizes that the outer stator 109 is located in a sealed cavity independent of the compressor cylinder 103, so that the outer stator 109 is independent of the working fluid, avoiding the release of non-metallic materials such as the windings on the outer stator 109 and causing contamination of the working fluid, thereby improving the reliability and life of the compressor 1.

[0083] The elastic support mechanism is used to provide elastic support for the end of the room temperature piston 105. The elastic support mechanism includes a leaf spring 114, a first screw 115, and a second screw 116. The leaf spring 114 is a circular plate structure. The center of the leaf spring 114 is fixedly connected to the end of the room temperature piston 105 by the first screw 115. The outer edge of the leaf spring 114 is fixedly connected to the leaf spring bracket 113 by a plurality of second screws 116 evenly distributed along the circumference.

[0084] The end cover 117 is welded to the leaf spring bracket 113. The two sets of compressor cylinders 103, the sealing mechanism and the end cover 117 together form the sealed cavity inside the compressor 1. The end cover 117 has a dome structure, which can effectively reduce the "vibration" effect caused by gas force, thereby reducing the vibration output of the compressor 1.

[0085] The pulse tube cold finger 4 includes a pulse tube hot end seat 41, a hot end heat exchanger 42, a cold finger cylinder 43, a cold head 44, a pulse tube 45, a rectifier wire mesh 46, and a regenerator 47. The hot end heat exchanger 42 and the cold head 44 are respectively disposed at the hot end and cold end of the cold finger cylinder 43. The pulse tube hot end seat 41 is disposed on the hot end heat exchanger 42. The pulse tube 45 is coaxially arranged inside the cold finger cylinder 43. The hot end of the pulse tube 45 is isolated from the hot end heat exchanger 42, and the cold end of the pulse tube 45 is connected to the cold head 44. The pulse tube hot end seat 41 has a rotating structure, and the inner end of the pulse tube hot end seat 41 is nested inside the hot end heat exchanger 42. The system includes a pulse tube mounting hole 411 for mounting the pulse tube 45. The outer end of the pulse tube hot end seat 41 has an outlet 412 that connects to the pulse tube 45 through the pulse tube mounting hole 411. A hot end heat exchanger 42 is welded to the flange face of the pulse tube hot end seat 41. The hot end heat exchanger 42 has an inlet 421 that connects to the cold finger cylinder 43. The cold finger cylinder 43 is a thin-walled cylindrical structure, welded to both the hot end heat exchanger 42 and the cold head 44. A KF flange standard interface is pre-reserved on the outer periphery of the hot end of the cold finger cylinder 43. The pulse tube 45 is a thin-walled cylindrical structure, with its hot end nested within the system. The pulse tube 45 is installed in the mounting hole 411 and welded to the hot end seat 41. Welding achieves a sealed isolation between the hot end of the pulse tube 45 and the hot end heat exchanger 42, preventing direct current flow caused by cross-flow and resulting efficiency loss. The cold end of the pulse tube 45 is installed in the inner hole of the cold head 44 with a transition fit. Rectifying wire mesh 46 is arranged at both the hot and cold ends of the pulse tube 45. The rectifying wire mesh 46 is a circular copper wire mesh with high thermal conductivity. As a laminar flow element, the rectifying wire mesh 46 ensures laminar flow when high-pressure gas enters the pulse tube 45. The regenerator 47 is filled between the cold finger cylinder 43 and the pulse tube 45. Inside the annular cavity, the regenerator 47 is an annular structure made of wire mesh, which can be made of copper or stainless steel. The main body of the regenerator 47 adopts a segmented mixed filling form from the hot end to the cold end, consisting of woven wire mesh and sintered wire mesh. Woven wire mesh is arranged on the outer side of the hot end and the outer side of the cold end of the main body of the regenerator 47. The porosity of the regenerator 47 can be adjusted by adjusting the weight ratio of woven wire mesh to sintered wire mesh, thus achieving adjustable porosity. This ensures that the specific heat capacity and specific surface area of ​​the regenerator 47 meet the requirements, while reducing axial heat conduction loss and pressure drop loss.

[0086] One end of the split pipe 2 is connected to the air inlet 421, and the other end of the split pipe 2 is connected to the two first compression chambers 106 through the central connection structure 101 and the two compressor heat exchangers 102.

[0087] The connecting pipe 3 is similar to an inertial tube. One end of the connecting pipe 3 is connected to the air outlet 412, and the other end of the connecting pipe 3 is connected to the second compression chamber 107 through the central connecting structure 101.

[0088] like Figure 2 , Figure 3As shown, the central connection structure 101 includes a cylinder mounting cylinder 1011, a central flange 1012, an annular groove 1013, an axial straight hole 1014, a first radial hole 1015, a second radial hole 1016, a vent hole 1017, and a weight reduction hole 1018. The cylinder mounting cylinder 1011 is a cylindrical structure, and two compressor cylinders 103 can be installed and positioned at both ends of the inner hole of the cylinder mounting cylinder 1011. The central flange 1012 is fixedly connected to the middle position of the outer periphery of the cylinder mounting cylinder 1011. The two end faces of the central flange 1012 are symmetrically provided with an annular groove 1013 surrounding the outer periphery of the cylinder mounting cylinder 1011. The annular groove 1013 is separated from the inner hole of the cylinder mounting cylinder 1011 by the side wall of the cylinder mounting cylinder 1011. The first radial hole 1015 is located outside the central flange 1012. The surface extends radially to the outer side of the cylinder mounting cylinder 1011. The axial straight hole 1014 penetrates the bottom surface of the two annular air grooves 1013 and connects to the first radial hole 1015. The branch pipe 2 connects to the first radial hole 1015. The second radial hole 1016 extends radially from the outer side of the central flange 1012 to the outer side of the cylinder mounting cylinder 1011. The vent hole 1017 penetrates the side wall of the cylinder mounting cylinder 1011 and connects to the second radial hole 1016. The connecting pipe 3 connects to the second radial hole 1016. The connecting pipe 3 connects to the second compression chamber 107 through the second radial hole 1016 and the vent hole 1017 in sequence. Multiple weight reduction holes 1018 are evenly distributed around the outer periphery of the annular air groove 1013. The weight reduction holes 1018 penetrate the two end faces of the central flange 1012 and reduce weight through the weight reduction holes 1018.

[0089] like Figure 4 As shown, the compressor heat exchanger 102 is machined from oxygen-free copper rods. The outer ring of the compressor heat exchanger 102 is the compressor heat exchanger base 1021, and an external radiator can be installed on the outer side of the compressor heat exchanger base 1021. The inner ring of the compressor heat exchanger 102 is machined by wire EDM to form multiple compressor heat exchanger fins 1022 that are evenly distributed circumferentially. Each compressor heat exchanger fin 1022 surrounds the outer circumference of the inner hole of the compressor heat exchanger 102. The cylinder mounting cylinder 1011 is nested in the inner hole of the compressor heat exchanger 102. The end face of the central flange 1012 is welded to the end face of the compressor heat exchanger base 1021. The annular gas groove 1013 communicates with the gap between the compressor heat exchanger fins 1022.

[0090] like Figure 5As shown, the compressor cylinder 103 is a rotating structure, including a cylinder body 1031, a cylinder flange 1032, through holes 1033, and a protruding structure 1034. The compression piston 104 and the room temperature piston 105 are both located within the cylinder body 1031 and form a gap seal with the cylinder body 1031. One end of the cylinder body 1031 is nested in the inner hole of the cylinder mounting cylinder 1011 for positioning. The cylinder flange 1032 is provided on the outer periphery of the cylinder body 1031, and the end face of the cylinder flange 1032 is welded to the end face of the compressor heat exchanger base 1021. Multiple through holes 1033 are evenly distributed circumferentially on the cylinder flange 1032, penetrating from the end face of the cylinder flange 1032 to the inner surface of the cylinder body 1031. Pipe 2 connects to two first compression chambers 106 sequentially through a first radial hole 1015, an axial straight hole 1014, two annular air grooves 1013, compressor heat exchanger fins 1022 of two compressor heat exchangers 102, and through holes 1033 of two compressor cylinders 103; a protruding structure 1034 is provided on the end face of the cylinder flange 1032 facing away from the compressor heat exchanger 102; the cylinder body of the support cylinder 111 is sleeved on the outside of the cylinder body 1031; the bottom flange of the support cylinder 111 is positioned and matched with the protruding structure 1034 and welded to the end face of the cylinder flange 1032; the cylinder body 1031 is provided with external threads for installing the inner stator 108; the surface of the compressor cylinder 103 is treated with a special process to ensure the wear resistance and hardness of the surface.

[0091] like Figure 6As shown, the compression piston 104 includes an outer compression piston layer 1041, an inner compression piston layer 1042, an inner compression piston bore 1043, an air inlet 1044, an air reservoir 1045, a one-way valve 1046, an air flow channel 1047, an air outlet 1048, and a balance groove 1049. The outer compression piston layer 1041 forms a gap seal with the compressor cylinder 103, and the inner compression piston layer 1042 is fitted and fixed inside the outer compression piston layer 1041. The inner layer 1042 of the compression piston has a compression piston inner bore 1043 for nesting the room temperature piston 105; the inner layer 1042 of the compression piston has multiple compression piston gas chambers 1045, and the compression piston inlet 1044 extends axially from the end face of the inner layer 1042 of the compression piston toward the first compression chamber 106 to one of the compression piston gas chambers 1045, which is equipped with a compression piston one-way valve 1046; the outer periphery of the outer layer 1041 of the compression piston has multiple compression piston outlet holes 1048, and each compression piston gas chamber 104... A compression piston airflow channel 1047 connects the compression piston air chamber 1045 and the compression piston air outlet 1048; two balance air grooves 1049 are symmetrically arranged and extend from both ends of the compression piston outer layer 1041 to the middle outer side of the compression piston outer layer 1041; the outer side of the compression piston outer layer 1041 is coated with a wear-resistant coating; the compression piston 104 is supported in the compressor cylinder 103 by an air bearing, and has no mechanical support in the axial and circumferential directions; the compression piston 104 is driven by a drive motor and can be compressed in the compressor. During the axial reciprocating motion within the cylinder 103 and the reciprocating motion of the compression piston 104, the high-pressure gas in the first compression chamber 106 sequentially enters the gap between the compression piston 104 and the compressor cylinder 103 through the compression piston inlet 1044, the compression piston gas reservoir 1045, the compression piston check valve 1046, the compression piston airflow channel 1047, and the compression piston outlet 1048, forming a high-pressure gas film with gas lubrication function. This high-pressure gas film supports the compression piston 104 to perform wear-free motion within the compressor cylinder 103.

[0092] like Figure 7As shown, the room temperature piston 105 includes a room temperature piston rod 1051, a room temperature piston outer layer 1052, a room temperature piston inner layer 1053, a room temperature piston inlet 1054, a room temperature piston air reservoir 1055, a room temperature piston one-way valve 1056, a room temperature piston airflow channel 1057, and a room temperature piston outlet 1058; the center of the leaf spring 114 is fixedly connected to the end of the room temperature piston rod 1051 by a first screw 115, the room temperature piston rod 1051 passes through the inner hole 1043 of the compression piston and forms a gap seal with the inner layer 1042 of the compression piston, the room temperature piston rod 1051... 051 is a slender rod structure with a certain degree of flexibility, ensuring that the room temperature piston 105 can automatically achieve centering, reducing the machining and assembly precision of the parts; the room temperature piston outer layer 1052 is fixedly connected to the room temperature piston rod 1051, and the room temperature piston outer layer 1052 forms a gap seal with the compressor cylinder 103; the room temperature piston inner layer 1053 is fitted and fixed inside the room temperature piston outer layer 1052; the room temperature piston inner layer 1053 is provided with a room temperature piston air chamber 1055, and the room temperature piston air inlet 1054 faces the second compressor from the room temperature piston inner layer 1053. The end face of cavity 107 extends axially to room temperature piston gas reservoir 1055, which is equipped with room temperature piston one-way valve 1056; the outer periphery of room temperature piston outer layer 1052 is provided with multiple room temperature piston outlet holes 1058, and a room temperature piston airflow channel 1057 connects room temperature piston gas reservoir 1055 and room temperature piston outlet holes 1058; the outer surface of room temperature piston outer layer 1052 is coated with a wear-resistant coating; the room temperature piston 105 is supported in compressor cylinder 103 by air bearings, and has no circumferential mechanical support, and the room temperature piston 105 is under pressure. The force wave drive can reciprocate axially within the compressor cylinder 103. During the reciprocating motion of the room temperature piston 105, the high-pressure gas in the second compression chamber 107 enters the gap between the room temperature piston 105 and the compressor cylinder 103 through the room temperature piston inlet 1054, the room temperature piston gas reservoir 1055, the room temperature piston check valve 1056, the room temperature piston airflow channel 1057, and the room temperature piston outlet 1058 in sequence, forming a high-pressure gas film with gas lubrication effect. This high-pressure gas film supports the room temperature piston 105 to perform wear-free movement within the compressor cylinder 103.

[0093] like Figure 8 As shown, the inner stator 108 includes an inner stator ring 1081 and a retaining ring 1082; the inner stator ring 1081 is a ring structure formed by stacking multiple inner magnetic pole pieces in the circumferential direction, and the inner magnetic pole pieces are made of soft magnetic material by stamping or wire cutting; the retaining ring 1082 is inserted into the inner hole of the inner stator ring 1081 and its end is welded to the end face of the inner stator ring 1081, and the retaining ring 1082 is provided with an internal thread that mates with the external thread on the cylinder body 1031, and the inner stator 108 is threadedly connected to the outside of the cylinder body 1031.

[0094] like Figure 9As shown, the outer stator 109 includes an outer stator block 1091, a winding frame 1092, an annular winding 1093, and pole shoes 1094. Multiple outer stator blocks 1091 are distributed around the circumference of the annulus. Each outer stator block 1091 is a C-shaped iron core structure with notches, formed by stacking multiple outer magnetic pole pieces circumferentially. The outer magnetic pole pieces are made of soft magnetic material by stamping or wire cutting. The winding frame 1092 is an annular structure, and the outer stator blocks 1091 pass through the notches... The winding frame 1092 is fixedly connected to the outer side of the winding frame 1092, which is fixedly connected to the outside of the support cylinder 111. The annular winding 1093 is disposed between the outer stator block 1091 and the winding frame 1092. The annular winding 1093 is made of polyimide enameled round copper layers and is separated from the outer stator block 1091 by insulating tape. Pole shoes 1094 are provided at both ends of the outer stator block 1091.

[0095] like Figures 10 to 12 As shown, the permanent magnet assembly 110 includes a permanent magnet skeleton 1101, main permanent magnets 1102, and auxiliary permanent magnets 1103. The permanent magnet skeleton 1101 has a ring structure and is movably disposed between the inner stator 108 and the support cylinder 111. The permanent magnet skeleton 1101 is fixedly connected to the outer layer 1041 of the compression piston by a plurality of screws evenly distributed along the circumference. The permanent magnet assembly 110 adopts an internal structure, with a plurality of main permanent magnets 1102 forming a ring and evenly distributed in pairs. Auxiliary permanent magnets 1103 are symmetrically arranged at both ends of the axial direction of each main permanent magnet 1102. The main permanent magnets 1102 and auxiliary permanent magnets 1103 are both glued to the inner side of the permanent magnet skeleton 1101 with high-strength adhesive. The main permanent magnets 1102 and auxiliary permanent magnets 1103 are fixedly connected to the outer layer 1041 of the compression piston by a plurality of screws evenly distributed along the circumference. All 1103 bodies have a tile-shaped structure and are made of metal powder metallurgy. The main permanent magnet 1102 and the auxiliary permanent magnet 1103 are radially magnetized with opposite magnetic polarities. By adjusting the size, number of pieces, and arrangement of the main permanent magnet 1102 and the auxiliary permanent magnet 1103, the natural alignment of the compression piston 104 can be achieved through the restoring force of the motor, ensuring the start-up of the refrigerator under harsh environments such as various postures, achieving phase consistency during normal operation, and realizing high reliability and high motor efficiency. The multi-segment magnet composed of the main permanent magnet 1102 and the auxiliary permanent magnet 1103 can limit the axial reciprocating stroke of the compression piston 104 and improve the thrust coefficient of the motor, realizing high thrust of the motor, while reducing the reactive power loss of the motor.

[0096] like Figure 13As shown, the leaf spring 114 includes a leaf spring body 1141, an inner mounting hole 1142, an outer mounting hole 1143, an inner profile 1144, an outer profile 1145, a head 1146, and a tail 1147. The leaf spring body 1141 is made of a metal sheet of a certain thickness. The center of the leaf spring body 1141 is provided with an inner mounting hole 1142 for connecting the room temperature piston 105 through a first screw 115. The outer edge of the leaf spring body 1141 is uniformly provided with a plurality of outer mounting holes along the circumferential direction for fixing the leaf spring body 1141 to the leaf spring bracket 113 through a second screw 116. Hole 1143; Multiple curved holes are provided on the leaf spring body 1141 between the inner mounting hole 1142 and the outer mounting hole 1143, which are evenly distributed in the circumferential direction. The curved holes are formed by multiple smooth arc transitions of the inner profile 1144, the outer profile 1145, the head 1146 and the tail 1147 to form a closed curve. The stiffness of the leaf spring 114 can be adjusted by adjusting the length and distance of the inner profile 1144 and the outer profile 1145. The stress concentration phenomenon of the leaf spring 114 can be reduced by adjusting the arc shape of the head 1146 and the tail 1147, thereby meeting the requirements of long service life.

[0097] like Figure 14 As shown, the hot-end heat exchanger 42 is machined from oxygen-free copper rods. The outer ring of the hot-end heat exchanger 42 is the hot-end heat exchanger base 422, and the air inlet 421 penetrates the side wall of the hot-end heat exchanger base 422. The inner ring of the hot-end heat exchanger 42 is machined by wire electrical discharge machining to form multiple circumferentially evenly distributed hot-end heat exchanger fins 423. Each hot-end heat exchanger fin 423 surrounds the outer periphery of the inner hole of the hot-end heat exchanger 42. The inner end of the pulse tube hot-end seat 41 is connected to each hot-end heat exchanger. A narrow annular channel is formed between the inner ends of the fins 423. This annular channel rectifies and equalizes the pressure of the high-pressure gas entering the cold finger cylinder 43. The end of the hot-end heat exchanger fins 423 facing the cold finger cylinder 43 protrudes from the end face of the hot-end heat exchanger base 422 to form a boss. The boss is nested in the inner hole of the cold finger cylinder 43 for positioning. The two end faces of the hot-end heat exchanger base 422 are welded to the end face of the cold finger cylinder 43 and the flange face of the pulse tube hot end seat 41, respectively.

[0098] like Figure 15 , Figure 16 As shown, the cold head 44 includes a cold cap 441 and cold end heat exchanger fins 442. The cold cap 441 is a cylindrical groove structure. Multiple cold end heat exchanger fins 442, which are processed by wire electrical discharge machining, are welded inside the cold cap 441 and are evenly distributed circumferentially. Each cold end heat exchanger fin 442 surrounds the outer periphery of the inner hole of the cold head 44. The end of the cold end heat exchanger fin 442 facing the groove of the cold cap 441 forms an arc dome structure, which can effectively increase the heat exchange area and reduce the heat transfer temperature difference.

[0099] Working principle:

[0100] On one hand, when alternating current is applied to the annular winding 1093 of the outer stator 109, an alternating magnetic field is generated in the annular magnetic gap between the inner stator 108 and the outer stator 109. Under the action of the alternating magnetic field, the permanent magnet assembly 110 reciprocates axially, driving the compression piston 104 to reciprocate axially within the compressor cylinder 103, converting electrical energy into the mechanical energy of the compression piston 104. The periodic reciprocating motion of the compression piston 104 drives the working fluid in the first compression chamber 106 to generate pressure waves with alternating high and low pressures. This alternating flow of gas passes sequentially through the through hole 1033, the compressor heat exchanger fins 1022, and the annular gas groove 101. 3. The working fluid enters the hot-end heat exchanger 42 through the axial straight hole 1014, the first radial hole 1015, and the distribution pipe 2 for heat exchange, and then enters the regenerator 47 to complete heat exchange with the regenerator 47, thus reducing the temperature of the working fluid. Then, the working fluid enters the pulse tube 45 through the cold-end heat exchanger fins 442 of the cold head 44, and then enters the second compression chamber 107 through the connecting pipe 2, the second radial hole 1016, and the vent hole 1017 in sequence, thereby pushing the room temperature piston 105 and storing effective work through the leaf spring 114. During the expansion process, the working fluid enters the first compression chamber 106 in the opposite direction of the original path to expand and absorb heat. This invention uses a room temperature piston to return work. The technology recovers the expansion work at the hot end of the pulse tube 45, improving the overall efficiency. By adjusting the weight of the room temperature piston 105, the diameter of the room temperature piston 105, the stiffness of the leaf spring 114, the diameter of the connecting pipe 3, and the length of the connecting pipe 3, the phase of the working fluid's mass flow and pressure can be adjusted to the optimal angle, achieving adjustable phase of the working fluid's mass flow and pressure. This ensures that the mass flow and pressure wave of the working fluid in the regenerator 47 obtain the best phase angle, achieving a 0° phase angle between the mass flow and pressure wave in the middle of the regenerator 47. This achieves the optimal matching between the compressor 1 and the pulse tube cooling index 4, realizing the high-efficiency operation of the whole machine and improving the overall refrigeration efficiency. The two linear compression mechanisms are arranged opposite each other to cancel out each other's vibrations. Specifically, adaptive vibration reduction is achieved by adjusting the piston movement phase and amplitude of the two linear compression mechanisms, which reduces the vibration output of compressor 1. Compressor 1 and pulse tube cold finger 4 adopt a separate structure, which reduces the mutual interference of vibration between compressor 1 and pulse tube cold finger 4. Combined with the fact that pulse tube cold finger 4 uses a "gas piston" instead of an exhaust device, with no mechanical moving parts, it achieves low vibration output of pulse tube cold finger 4. Room temperature piston 105 replaces the traditional gas reservoir-inertial tube phase adjustment mechanism. Room temperature piston 105 is coupled and embedded inside compressor 1, realizing the miniaturization and weight reduction of pulse tube cold finger 4.

[0101] On the other hand, a small portion of the high-pressure gas in the first compression chamber 106 and the second compression chamber 107 enters the compression piston 104 and the room temperature piston 105 through the compression piston inlet 1044 and the room temperature piston inlet 1054, and is then discharged through the compression piston outlet 1048 and the room temperature piston outlet 1058, forming a hydrostatic air bearing. A pressure gas film is formed between the compression piston 104 and the compressor cylinder 103, and between the room temperature piston 105 and the compressor cylinder 103. This pressure gas film allows the compression piston 104 and the room temperature piston 105 to be stably suspended inside the compressor cylinder 103 and has a gas lubrication effect, realizing wear-free movement of the compression piston 104 and the room temperature piston 105, resulting in stable operation of the moving parts with no wear, long service life, and high reliability.

[0102] Finally, the restoring force generated between the inner stator 108 and the outer stator 109 by the multi-segment magnet composed of the main permanent magnet 1102 and the auxiliary permanent magnet 1103 can automatically drive the permanent magnet assembly 110 to center to the balance position of the drive motor, achieving self-centering. This multi-segment magnet can limit the axial reciprocating stroke of the compression piston 104, effectively avoiding the drive motor starting failure caused by the compression piston 104 exceeding its stroke and impacting the compressor cylinder 103 or leaf spring 114 due to an unknown position. It also avoids the complex free piston starting control program and achieves starting under complex and harsh conditions (different postures, different environments). The drive motor can start efficiently and reliably under varying ambient temperatures and mechanical overload conditions. Simultaneously, the self-centering restoring force ensures the consistency of phase and amplitude during normal operation of the refrigeration unit, effectively reducing the residual force of the opposed motor and achieving low vibration output. This multi-segment magnet improves the motor's thrust coefficient, enabling the drive motor to achieve high thrust within a small volume. By adjusting the operating frequency and charging pressure, optimal matching between the drive motor and compressor 1 and pulse tube cooling index 4 is achieved, thereby realizing high efficiency of the drive motor, efficiently converting electrical work into acoustic work, achieving efficient operation of the entire unit, and obtaining optimal refrigeration efficiency.

[0103] In summary, addressing the problems of large size, heavy weight, high power consumption, low efficiency, high vibration, and inability to achieve long lifespan in traditional Stirling and pulse tube refrigerators, this invention is the first to adopt a wear-free support technology using fully air-bearing bearings. Specifically, both the compression piston 104 and the room-temperature piston 105 are supported by air-bearing bearings within the compressor cylinder 103, increasing the refrigerator's lifespan to over 10 years. This eliminates the need for traditional diaphragm springs and their complex support structures, achieving a compact structure, small size, and light weight. Furthermore, room-temperature piston work recovery technology recovers the expansion work at the hot end of the pulse tube 45, enabling phase adjustment and improving refrigeration efficiency. Simultaneously, the room-temperature piston 105 replaces the traditional gas reservoir-inertial tube phase adjustment mechanism, and is coupled and embedded in the compressor 103. Internally, the miniaturization and lightweighting of the pulse tube cold finger 4 are achieved; the two linear compression mechanisms are arranged opposite each other to cancel out vibrations, the separate structure vibration isolation technology and the absence of moving parts in the pulse tube achieve low vibration output interference for the compressor 1 and the pulse tube cold finger 4; the use of free piston self-centering and adjustable restoring force linear technology achieves free piston start-up, high-efficiency operation and phase matching consistency, increasing the compressor efficiency to over 92%; the use of a moving magnet drive motor, with the annular winding 1093 of the outer stator 109 adopting an external structure independent of the internal working fluid, eliminates coil flying wire and working fluid contamination problems, and improves the reliability and lifespan of the compressor 1; the coaxial pulse tube cold finger has many advantages such as low vibration, compact structure, small size, light weight and ease of use.

[0104] Example 2

[0105] like Figure 17 As shown, the difference between this embodiment and Embodiment 1 is that: the compressor cylinder 103 is divided into two sections along the axial direction, namely the cylinder large end 1035 and the cylinder small end 1036, the inner diameter and outer diameter of the cylinder large end 1035 are both larger than those of the cylinder small end 1036; the compression piston 104 is located inside the cylinder large end 1035 and forms a gap seal with the cylinder large end 1035, the room temperature piston 105 is located inside the cylinder small end 1036 and forms a gap seal with the cylinder small end 1036; the cylinder small end 1036 is nested in the inner hole of the cylinder mounting cylinder 1011. Positioning: The end face of the cylinder head 1035 is welded to the end face of the compressor heat exchanger base 1021; multiple through holes 1033 are evenly distributed circumferentially on the cylinder head 1035, and the through holes 1033 penetrate the end face of the cylinder head 1035; a cylinder flange 1032 is provided on the outer periphery of the cylinder head 1035, and the cylinder body of the support cylinder 111 is sleeved on the outside of the cylinder head 1035, and the bottom flange of the support cylinder 111 is welded to the end face of the cylinder flange 1032; the cylinder head 1035 is provided with external threads for installing the inner stator 108.

[0106] Example 3

[0107] like Figure 18As shown, the difference between this embodiment and Embodiment 1 is that the permanent magnet assembly 110 adopts an external structure, and the main permanent magnet 1102 and the auxiliary permanent magnet 1103 are both attached to the outer side of the permanent magnet skeleton 1101 with high-strength adhesive.

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A room temperature reciprocating Stirling pulse tube refrigerator, characterized in that: Includes compressor, distribution pipe, connecting pipe, and pulse cooling finger; The compressor includes a central connecting structure and two sets of compressor heat exchangers, a linear compression mechanism, a drive motor, and an elastic support mechanism, which are oppositely distributed on both sides of the central connecting structure. The linear compression mechanism includes a compressor cylinder, a compression piston, a room temperature piston, a first compression chamber, and a second compression chamber. The room temperature piston is coaxially nested inside the compression piston and is movably engaged with the compression piston. The cavity between the compression piston and the room temperature piston is the first compression chamber, and the cavity between the room temperature pistons of the two sets of linear compression mechanisms is the second compression chamber. The drive motor is used to drive the compression piston to reciprocate axially within the compressor cylinder, and the elastic support mechanism is used to provide elastic support for the end of the room temperature piston. One end of the split tube is connected to the air inlet of the pulse tube cold finger, and the other end of the split tube is connected to the two first compression chambers through the central connection structure and the two compressor heat exchangers; One end of the connecting tube is connected to the air outlet of the pulse cold finger, and the other end of the connecting tube is connected to the second compression chamber through the central connecting structure; Both the compression piston and the room temperature piston are supported by air bearings within the compressor cylinder. The compression piston includes an outer compression piston layer, an inner compression piston layer, an inner compression piston bore, a compression piston inlet, a compression piston gas reservoir, a compression piston check valve, a compression piston airflow channel, a compression piston outlet, and a balancing gas groove. The inner compression piston layer is fixedly connected inside the outer compression piston layer. The inner compression piston layer is provided with multiple compression piston gas reservoirs. The compression piston inlet extends from the end face of the inner compression piston layer toward the first compression chamber to one of the compression piston gas reservoirs, and the compression piston check valve is provided in the compression piston gas reservoir. The outer periphery of the outer compression piston layer is provided with multiple compression piston outlets. The compression piston airflow channel connects the compression piston gas reservoirs and the compression piston outlet. Two balancing gas grooves are symmetrically arranged and extend from both ends of the outer compression piston layer to the outer surface of the outer compression piston layer.

2. The room temperature piston-type Stirling pulse tube refrigerator according to claim 1, characterized in that: The room temperature piston includes a room temperature piston outer layer, a room temperature piston inner layer, a room temperature piston inlet, a room temperature piston gas reservoir, a room temperature piston one-way valve, a room temperature piston airflow channel, and a room temperature piston outlet. The room temperature piston inner layer is fixedly connected inside the room temperature piston outer layer. The room temperature piston inner layer is provided with a room temperature piston gas reservoir. The room temperature piston inlet extends axially from the end face of the room temperature piston inner layer toward the second compression chamber to the room temperature piston gas reservoir. The room temperature piston one-way valve is provided in the room temperature piston gas reservoir. The outer periphery of the room temperature piston outer layer is provided with multiple room temperature piston outlets. The room temperature piston gas reservoir and the room temperature piston outlets are connected by a room temperature piston airflow channel.

3. The room temperature reciprocating Stirling pulse tube refrigerator according to claim 1, characterized in that: The central connection structure includes a cylinder mounting cylinder, a central flange, an annular groove, an axial straight hole, a first radial hole, a second radial hole, and a vent hole. The central flange is fixedly connected to the middle of the outer periphery of the cylinder mounting cylinder. The two end faces of the central flange are symmetrically provided with annular grooves surrounding the outer periphery of the cylinder mounting cylinder. The annular grooves are separated from the inner hole of the cylinder mounting cylinder by the side wall of the cylinder mounting cylinder. The first radial hole extends from the outer side of the central flange to the outer side of the cylinder mounting cylinder. The axial straight hole penetrates the bottom surface of the two annular grooves and connects to the first radial hole. The distribution pipe connects to the first radial hole. Multiple through holes are evenly distributed circumferentially on the compressor cylinder. The distribution pipe connects to the two first compression chambers sequentially through the first radial hole, the axial straight hole, the two annular grooves, the two compressor heat exchangers, and the through holes on the two compressor cylinders. The second radial hole extends from the outer side of the central flange to the outer side of the cylinder mounting cylinder. The vent hole penetrates the side wall of the cylinder mounting cylinder and communicates with the second radial hole. The connecting pipe is connected to the second radial hole. The connecting pipe communicates with the second compression chamber in sequence through the second radial hole and the vent hole.

4. The room temperature reciprocating Stirling pulse tube refrigerator according to claim 1, characterized in that: The drive motor includes an inner stator, an outer stator, and a permanent magnet assembly; the inner stator, the permanent magnet assembly, and the outer stator are coaxially arranged from the inside to the outside of the compressor cylinder; the inner stator and the outer stator are fixedly disposed relative to the compressor cylinder, and the permanent magnet assembly is movably disposed in the annular magnetic gap between the inner stator and the outer stator and is fixedly connected to the compression piston; the outer stator is located in a sealed cavity independent of the compressor cylinder.

5. The room temperature piston-type Stirling pulse tube refrigerator according to claim 4, characterized in that: The permanent magnet assembly includes main permanent magnets and auxiliary permanent magnets. Multiple main permanent magnets are arranged in a ring and are evenly distributed in pairs. Auxiliary permanent magnets are symmetrically arranged at both ends of the axial direction of each main permanent magnet. Both the main permanent magnets and the auxiliary permanent magnets are radially magnetized and have opposite magnetic polarities.

6. The room temperature piston-type Stirling pulse tube refrigerator according to claim 1, characterized in that: The pulse tube cold finger includes a pulse tube hot end seat, a hot end heat exchanger, a cold finger cylinder, a cold head, a pulse tube, a rectifier wire mesh, and a regenerator. The hot end heat exchanger and the cold head are respectively disposed at the hot end and cold end of the cold finger cylinder. The pulse tube hot end seat is disposed on the hot end heat exchanger. The pulse tube is coaxially arranged inside the cold finger cylinder. The hot end of the pulse tube is isolated from the hot end heat exchanger, and the cold end of the pulse tube is connected to the cold head. The pulse tube hot end seat is provided with an outlet connecting to the pulse tube, and the hot end heat exchanger is provided with an inlet connecting to the cold finger cylinder. Rectifier wire meshes are respectively arranged at the hot end and cold end of the pulse tube. The regenerator fills the annular cavity between the cold finger cylinder and the pulse tube.

7. The room temperature reciprocating Stirling pulse tube refrigerator according to claim 6, characterized in that: The regenerator is a ring structure made of wire mesh. The main body of the regenerator is filled in a segmented mixed form of woven wire mesh and sintered wire mesh from the hot end to the cold end. Woven wire mesh is arranged on the outer side of the hot end and the outer side of the cold end of the main body of the regenerator.

8. The room temperature reciprocating Stirling pulse tube refrigerator according to claim 1, characterized in that: The elastic support mechanism includes a leaf spring, which includes a leaf spring body, an inner mounting hole, an outer mounting hole, an inner profile, an outer profile, a head, and a tail. The center of the leaf spring body is provided with an inner mounting hole for connecting the room temperature piston, and the outer edge of the leaf spring body is provided with multiple outer mounting holes for fixing the leaf spring body. The leaf spring body is provided with multiple curved holes evenly distributed circumferentially between the inner mounting hole and the outer mounting hole. The curved holes are formed by multiple smooth arc transitions from the inner profile, the outer profile, the head, and the tail to form a closed curve.

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