A gas bearing linear compressor and linear stirling refrigerator

Abstract

The present application relates to linear refrigeration machine technical field, especially in kind of gas bearing linear compressor and linear Stirling refrigeration machine. Including linear motor system, main piston compression system and vice piston compression system, main piston compression system and vice piston compression system are located at the two sides of linear motor system respectively and are driven by linear motor system, the compressed gas generated by vice piston compression system is simultaneously gas bearing gas supply for main piston compression system and vice piston compression system. Linear motor system drives main piston compression system to do periodic linear reciprocating motion, and it is also used for the support of the gas bearing of main piston compression system; adopt self-gas supply structure, gas bearing structure is installed between all pistons and cylinders, avoids the contact friction of piston and cylinder, the theoretical failure time of compressor and expander is consistent, improves the efficiency of the whole refrigeration machine, improves the reliability and life of the whole refrigeration machine.

Description

Technical Field

[0001] This invention relates to the field of linear refrigeration technology, and particularly to a gas bearing linear compressor and a linear Stirling refrigeration machine. Background Technology

[0002] As the core component of a linear Stirling refrigerator, the linear compressor features resonant operation, gap sealing, and a complex transmission mechanism without crankshafts and connecting rods. Compared to traditional rotary Stirling refrigerators, linear Stirling refrigerators offer technological advantages such as less mechanical wear, higher motor efficiency, and longer lifespan.

[0003] Clearance sealing technology is crucial for achieving oil-free operation, low wear, and high reliability in linear Stirling refrigerators. To achieve clearance sealing, the single-sided sealing gap between the piston and cylinder is typically less than 10µm, and high coaxiality is required, posing challenges to the support structure. In engineering, multiple flexible leaf spring assemblies are commonly used to support the piston components to reduce dry friction between the piston and cylinder. However, the use of leaf spring assemblies increases the compressor's weight, size, piston-cylinder assembly difficulty, and cost. Therefore, developing novel support technologies has become a research trend.

[0004] Gas bearing technology is a support technology that uses gas as a lubricating medium. It is commonly used in rotating machinery and has since been applied to linear reciprocating machinery, such as linear compressors. Gas bearing technology requires a continuous supply of high-pressure gas between the piston and cylinder, maintaining a unidirectional pressure difference. However, the linear compressor used in Stirling refrigerators generates sinusoidal pressure waves, necessitating a high-pressure system on the linear compressor to achieve the unidirectional pressure difference required for the gas bearing. The high-pressure system required for the gas bearing structure of a linear compressor can be either an external high-pressure gas supply system or an internal high-pressure gas supply system. External high-pressure systems, due to the need for additional equipment, are less practical for engineering applications.

[0005] According to research, the gas bearing technology used in linear Stirling refrigerators is mainly applied to linear compressors, while the expander is overlooked. In fact, expanders typically use cylindrical springs, whose radial support is inferior to that of linear compressors. Therefore, dry friction inevitably exists between the piston and cylinder, causing the expander to fail earlier than the compressor, thus shortening the overall reliability and lifespan of the linear Stirling refrigerator.

[0006] Furthermore, with the miniaturization of cryogenic refrigerators, the conventional internal gas supply type gas bearing structure of linear compressors will no longer be suitable, necessitating the development of new gas bearing structures. Therefore, the design of the internal gas supply system and the gas bearing system covering all piston cylinders of the linear Stirling refrigerator is of great value in improving the operational reliability and service life of the linear Stirling refrigerator.

[0007] Conventional linear Stirling refrigerators employ internal gas bearing structures for compressors (such as patents CN204677392U and CN 104806471A) by installing a one-way valve on the end face of a hollow piston and arranging throttling elements (such as throttling orifices or multi-cavity media) on the piston cylinder surface. The working principle is as follows: when the piston compresses gas to a certain pressure, the one-way valve on the piston end face opens, allowing the high-pressure gas in the compression chamber to enter the internal cavity of the piston. When the piston moves in the opposite direction to expand, the one-way valve closes because the gas pressure in the piston's internal chamber is greater than the pressure in the compression chamber. Throughout the entire operation, the high-pressure gas in the piston cavity enters the piston-cylinder gap through the throttling element on the piston cylinder surface, forming a gas film. This gas film supports the piston, preventing direct contact between the piston and cylinder.

[0008] Based on the working principle of the internal gas-supply type gas bearing structure in a linear Stirling refrigerator, the following defects can be identified in this gas bearing structure:

[0009] 1) Conventional linear Stirling refrigerators only have gas bearings in the compressor, while the expander does not. This results in a longer compressor lifespan, while the expander has a shorter lifespan due to dry friction. This further leads to the expander failing before the compressor, thus shortening the overall reliability and lifespan of the refrigerator.

[0010] 2) Conventional gas bearing structures are not suitable for miniature Stirling refrigerators.

[0011] To ensure continuous operation of the gas bearing, the structure must guarantee that the amount of high-pressure gas flowing into the piston's hollow chamber during the brief opening and closing of the one-way valve is sufficient to meet the minimum gas volume required for continuous operation of the gas bearing throughout the compressor's entire lifespan. This necessitates a sufficiently large piston chamber, meaning the piston size must be large, which is detrimental to the miniaturization of linear compressors and refrigeration units. Furthermore, with the miniaturization of linear compressors, when the piston diameter is small (typically less than 9mm), the design and installation difficulties of the one-way valve located on the piston end face increase dramatically, ultimately making it impractical in engineering, and the gas bearing structure will completely fail.

[0012] 3) The high-pressure gas in this gas bearing structure comes from the high-pressure gas in the compression chamber, which reduces the amount of gas delivered from the linear compressor to the refrigeration unit and lowers the overall efficiency of the refrigeration unit.

[0013] Therefore, a solution is needed to address the aforementioned problems in existing technologies. Summary of the Invention

[0014] To solve the above-mentioned technical problems, according to one aspect of the present invention, the present invention provides a technical solution: a linear compressor system that generates high-pressure gas is added to a traditional linear Stirling refrigerator as a gas source for the gas bearings. The two gas bearing systems of the linear compressor and the gas bearing system on the expander are connected to the high-pressure gas source through connecting pipes, thereby realizing the function of gas bearings between all pistons and cylinders, avoiding dry friction, improving the reliability and lifespan of the refrigerator, and at least solving some of the problems existing in the prior art.

[0015] A gas bearing linear compressor includes a linear motor system, a main piston compression system, and a secondary piston compression system. The main piston compression system and the secondary piston compression system are located on both sides of the linear motor system and are both driven by the linear motor system. The compressed gas generated by the secondary piston compression system simultaneously supplies gas to the gas bearings of the main piston compression system and the secondary piston compression system.

[0016] As a preferred embodiment of the gas bearing linear compressor of the present invention, the main piston compression system includes a main cylinder and a main piston slidably disposed within the main cylinder. A main cylinder throttling element is provided on the main cylinder, and a high-pressure gas storage chamber B is provided on the outside of the main cylinder. The auxiliary piston compression system includes an auxiliary cylinder and an auxiliary piston slidably disposed within the auxiliary cylinder. An auxiliary cylinder throttling element is provided on the auxiliary cylinder, and a high-pressure gas storage chamber A is provided on the outside of the auxiliary cylinder. The high-pressure gas storage chamber A is connected to the compression chamber of the auxiliary piston compression system, and the high-pressure gas storage chamber B is connected to the high-pressure gas storage chamber A through an internal connecting pipe.

[0017] As a preferred embodiment of the gas bearing linear compressor of the present invention, the high-pressure gas storage chamber B is formed by the main cylinder and the compressor housing; the high-pressure gas storage chamber A is formed by the auxiliary cylinder and the compressor housing.

[0018] As a preferred embodiment of the gas bearing linear compressor of the present invention, the front end of the auxiliary piston is provided with an intake port and an intake valve plate is provided on the intake port. The front end of the auxiliary cylinder is provided with an exhaust port and an exhaust valve plate is provided on the exhaust port. Through the cooperation of the intake valve plate and the exhaust valve plate, the working gas in the auxiliary cylinder is periodically compressed, exhausted, expanded and intakeed. The high-pressure gas generated during the exhaust process is stored in the high-pressure gas storage chamber A as the total gas source of the gas bearing.

[0019] As a preferred embodiment of the gas bearing linear compressor of the present invention, the linear motor system includes a column spring A, an outer stator, a motor mover, an inner stator, and an excitation element; one end of the motor mover is fixedly connected to the auxiliary piston, and the other end is fixedly connected to the main piston; the column spring A connects the main piston and the auxiliary piston respectively within the linear compressor housing; the outer stator and the excitation element are arranged around the motor mover and the inner stator.

[0020] In a preferred embodiment of the gas bearing linear compressor described in this invention, the diameter of the auxiliary piston is larger than the diameter of the main piston.

[0021] As another technical solution of the present invention:

[0022] A linear Stirling refrigerator includes a linear compressor and an expander as described above, wherein the compression chamber of the main piston compression system is connected to the expander via a main connecting pipe and a high-pressure connecting pipe.

[0023] As a preferred embodiment of the linear Stirling refrigerator described in this invention, the compressed gas generated by the auxiliary piston compression system also supplies gas to the gas bearing of the piston compression system of the expander.

[0024] As a preferred embodiment of the linear Stirling refrigerator of the present invention, the piston compression system of the expander includes an expander cylinder and an expander piston slidably disposed in the expander cylinder. The expander cylinder is provided with an expander cylinder throttling element, and a high-pressure gas storage chamber C is provided on the outside of the expander cylinder. The high-pressure gas storage chamber C is connected to the compression chamber of the auxiliary piston compression system through a high-pressure connecting pipe.

[0025] As a preferred embodiment of the linear Stirling refrigerator of the present invention, the expander further includes an expansion chamber, a cold accumulator, and a column spring B; the expansion chamber is located above the inner cavity of the expander housing and is connected to the main connecting pipe, and a cold accumulator is provided inside it; the bottom end of the cold accumulator is connected to the top end of the expander piston, and the bottom end of the expander piston is connected to the lower part of the inner cavity of the expander housing through the column spring B.

[0026] Compared with existing technologies, this invention proposes a linear Stirling refrigerator, which has the following advantages:

[0027] 1) The refrigeration unit has high reliability and long service life.

[0028] The refrigeration unit employs a self-supplying gas structure, and gas bearings are installed between all pistons and cylinders. When the refrigeration unit is running, a gas film exists between all pistons and cylinders, including the compressor and expander, avoiding contact friction between the pistons and cylinders. The theoretical failure times of the compressor and expander are consistent, improving the overall reliability and lifespan of the refrigeration unit.

[0029] 2) Compact structure, high power-to-weight ratio, and high efficiency.

[0030] The refrigeration unit employs a single motor driving two piston compression systems. One system generates high-pressure gas, while the other generates pressure waves. This design is compact, saves on a separate motor system, and offers a high power-to-weight ratio. The two piston compression systems are coupled and mutually recover compression work, ensuring the linear motor's mover remains stationary and its efficiency is high. Furthermore, the presence of gas bearings significantly reduces frictional damping losses, thus improving the overall efficiency of the refrigeration unit.

[0031] 3) Suitable for all sizes (including miniature) of linear Stirling refrigerators

[0032] In the compressor of a refrigeration unit, the diameters of the high-pressure supply piston and the main piston are independent, making it suitable for all sizes (including miniature) of linear Stirling refrigeration units. For miniature linear Stirling refrigeration units, the diameter of the high-pressure supply piston can be larger than that of the main piston. The air supply volume is matched with the air consumption of all gas bearings by adjusting the size and stiffness of the intake and exhaust valve plates.

[0033] 4) Low manufacturing cost

[0034] Because of the presence of gas bearings, the refrigeration unit can avoid using expensive leaf spring assemblies, making it possible to use cheaper column springs; in addition, the compressor uses a structure in which two sets of piston compression systems share a single motor, further reducing manufacturing costs. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the gas bearing linear compressor and linear Stirling refrigerator involved in the present invention.

[0037] Explanation of icon numbers:

[0038] Connecting pipe 1, exhaust valve plate 2, intake valve plate 3, auxiliary cylinder 4, auxiliary cylinder throttling element 5, auxiliary piston 6, high-pressure storage chamber A 7, column spring A 8, outer stator 9, motor mover 10, inner stator 11, excitation element 12, main piston 13, main cylinder throttling element 14, main cylinder 15, high-pressure storage chamber B 16, main connecting pipe 17, high-pressure connecting pipe 18, expansion chamber 19, accumulator 20, expander piston 21, expander cylinder 22, expander cylinder throttling element 23, high-pressure storage chamber C 24, column spring B 25.

[0039] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0040] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0043] Example 1

[0044] A gas bearing linear compressor includes a linear motor system, a main piston compression system, and a secondary piston compression system. The main and secondary piston compression systems are located on opposite sides of the linear motor system and are both driven by it. The compressed gas generated by the secondary piston compression system simultaneously supplies gas to the gas bearings of both the main and secondary piston compression systems. This invention employs a single motor to drive two piston compression systems. The main piston compression system generates high-pressure gas, while the secondary piston compression system generates pressure waves. Both systems achieve piston-cylinder alignment via gas bearings, creating a gas film between the piston and cylinder for support and preventing contact friction. In this embodiment, the pressure waves generated by the secondary piston compression system supply gas to the gas bearings of both systems, achieving self-supply of the compressor without the need for a separate gas supply device. This results in a simple and compact structure, saving a motor system and achieving a high power-to-weight ratio. Furthermore, the two piston compression systems are mutually coupled and mutually recover compression work, preventing the linear motor's mover from shifting and ensuring high motor efficiency.

[0045] The main piston compression system includes a main cylinder 15 and a main piston 13 slidably disposed within the main cylinder 15. A main cylinder throttling element 14 is provided on the main cylinder 15, and a high-pressure storage chamber B16 is provided on the outside of the main cylinder 15. The auxiliary piston compression system includes an auxiliary cylinder 4 and an auxiliary piston 6 slidably disposed within the auxiliary cylinder 4. An auxiliary cylinder throttling element 5 is provided on the auxiliary cylinder 4, and a high-pressure storage chamber A7 is provided on the outside of the auxiliary cylinder 4. The high-pressure storage chamber A7 is connected to the compression chamber of the auxiliary piston compression system, and the high-pressure storage chamber B16 is connected to the high-pressure storage chamber A7 through an internal connecting pipe 1.

[0046] In this embodiment, the high-pressure gas storage chamber B16 is formed by the main cylinder 15 and the compressor housing; the high-pressure gas storage chamber A7 is formed by the auxiliary cylinder 4 and the compressor housing. That is, the space enclosed by the outer side of the cylinder and the compressor housing serves as the gas storage chamber, eliminating the need for an additional high-pressure gas storage chamber structure, resulting in a simple and compact overall structure. Furthermore, the internal connecting pipe 1 also utilizes the compressor housing as part of its structure, simplifying the installation of the internal connecting pipe 1.

[0047] The front end of the auxiliary piston 6 is provided with an intake port, and an intake valve plate 3 is provided on the intake port. The front end of the auxiliary cylinder 4 is provided with an exhaust port, and an exhaust valve plate 2 is provided on the exhaust port. Through the cooperation of the intake valve plate 3 and the exhaust valve plate 2, the working gas in the auxiliary cylinder 4 is periodically compressed, exhausted, expanded and intakeed. The high-pressure gas generated during the exhaust process is stored in the high-pressure gas storage chamber A7 as the total gas source of the gas bearing.

[0048] The linear motor system includes a column spring A8, an outer stator 9, a motor mover 10, an inner stator 11, and an excitation element 12, arranged sequentially from the inside out. When alternating current is applied to the linear motor, the motor mover 10 experiences electromagnetic force in the magnetic field and performs linear reciprocating motion under the drive of the axial electromagnetic force. The main piston compression system consists of a main piston 13 and a main cylinder 14. The main piston 13 is fixedly connected to one end of the motor rotor 10 and performs periodic linear reciprocating motion under the drive of the motor rotor 10. The auxiliary piston 6 is fixedly connected to the other end of the motor rotor 10 and performs periodic linear reciprocating motion under the drive of the motor rotor 10. At the same time, the working gas in the main cylinder 14 undergoes periodic compression and expansion processes under the drive of the main piston 13, and enters and exits the expander through the main connecting pipe 17. The working gas exchanges heat in the accumulator and generates cooling capacity in the expansion chamber 19, ultimately completing the entire Stirling refrigeration cycle. Multiple column springs A8 are connected to the main piston 13 and auxiliary piston 6 at both ends of the motor rotor 10, respectively, within the linear compressor housing. On the one hand, they provide radial support for the main piston 13 and auxiliary piston 6, and on the other hand, they buffer and limit the axial displacement of the main piston 13 and auxiliary piston 6.

[0049] The high-pressure gas in the main gas source exists in two branches. The first branch involves gas from the high-pressure storage chamber A7 continuously entering the gap between the auxiliary piston 6 and the auxiliary cylinder 4 through the auxiliary cylinder throttling element 5, forming a gas film that acts as a radially supporting gas bearing. The second branch involves gas from the high-pressure storage chamber A7 entering the high-pressure storage chamber B16 through the compressor's internal connecting pipe 1; one path of working gas in the high-pressure storage chamber B16 enters the gap between the main piston 13 and the main cylinder 15 through the main cylinder throttling element 14, forming a gas film that also acts as a radially supporting gas bearing. The remaining working gas in the high-pressure storage chamber B16 enters the expander through the high-pressure connecting pipe 18.

[0050] Example 2

[0051] like Figure 1 As shown, this invention relates to a linear Stirling refrigerator, including the aforementioned linear compressor, as well as a main connecting pipe 17, a high-pressure connecting pipe 18, and an expander. The compression chamber of the main piston compression system of the linear compressor is connected to the expander via the main connecting pipe 17. The compressed gas generated by the auxiliary piston compression system of the linear compressor also supplies gas to the gas bearing of the piston compression system of the expander.

[0052] The expander consists of an expansion chamber 19, a coolant accumulator 20, an expander piston 21, an expander cylinder 22, an expander cylinder throttling element 23, a high-pressure gas storage chamber C24, and a column spring B25. The expansion chamber 19 is located above the inner cavity of the expander housing and communicates with the main connecting pipe 17. The coolant accumulator 20 is housed inside the expansion chamber 19. The bottom end of the coolant accumulator 20 is connected to the top end of the expander piston 21, and the bottom end of the expander piston 21 is connected to the lower part of the inner cavity of the expander housing via the column spring B25. Driven by the working gas from the connecting pipe 17, the moving assembly composed of the coolant accumulator 20, the expander piston 21, and the column spring 25 performs periodic linear reciprocating motion. The heat in the expansion chamber 19 is transported to the lower end of the coolant accumulator 20 and then dissipated into the environment. The gas temperature in the expansion chamber 19 gradually decreases until it reaches thermal equilibrium with the object being cooled. The piston compression system of the expander includes an expander cylinder 22 and an expander piston 21 slidably disposed within the expander cylinder 22. An expander cylinder throttling element 23 is installed on the expander cylinder 21. A high-pressure gas storage chamber C24 is located outside the expander cylinder 21. The high-pressure gas storage chamber C24 is connected to the compression chamber of the auxiliary piston compression system via a high-pressure connecting pipe 18, specifically, it can be directly connected to the high-pressure gas storage chamber B16. It is also connected to the compression chamber of the auxiliary piston compression system via the high-pressure gas storage chamber B16, the connecting pipe 1, and the high-pressure gas storage chamber A7. The high-pressure gas storage chamber C24 is connected to the novel self-supplying gas bearing system of the linear compressor via the high-pressure connecting pipe 18. High-pressure gas continuously and unidirectionally flows into the gap between the expander piston 21 and the expander cylinder 22 through the expander cylinder throttling element 23, forming a gas film and achieving the radial support of the gas bearing.

[0053] This invention enables the refrigerator to supply high-pressure gas itself and realizes the function of gas bearings between all pistons and cylinders, avoiding dry friction and improving the reliability and lifespan of the refrigerator.

[0054] Example 3

[0055] The gas bearing linear compressor differs from Embodiment 1 in that the types and sizes of the intake and exhaust valves can be modified as needed.

[0056] Example 4

[0057] The gas bearing linear compressor differs from Embodiment 1 in that the main piston 13 and the auxiliary piston 6 can be driven by two linear motors, which drive the two types of pistons respectively.

[0058] Example 5

[0059] The linear Stirling refrigerator differs from Example 2 in that the mechanical support structure for the compressor and expander can be made of leaf springs.

[0060] The type and number of expanders can be changed; the number of linear compressors can be changed; the linear motor system can adopt moving coil type, moving magnet type, and moving iron type, etc.

[0061] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A linear Stirling refrigerator, characterized in that: This includes gas bearing linear compressors and expanders; The gas bearing linear compressor includes a linear motor system, a main piston compression system, and a secondary piston compression system. The main piston compression system and the secondary piston compression system are located on both sides of the linear motor system and are both driven by the linear motor system. The compressed gas generated by the secondary piston compression system simultaneously supplies gas to the gas bearings of the main piston compression system and the secondary piston compression system. The compression chamber of the main piston compression system is connected to the expander through the main connecting pipe, and the compressed gas generated by the auxiliary piston compression system also supplies gas to the gas bearing of the piston compression system of the expander.

2. A linear Stirling refrigerator according to claim 1, characterized in that: The main piston compression system includes a main cylinder and a main piston slidably disposed within the main cylinder. A main cylinder throttling element is provided on the main cylinder, and a high-pressure gas storage chamber B is provided on the outside of the main cylinder. The auxiliary piston compression system includes an auxiliary cylinder and an auxiliary piston slidably disposed within the auxiliary cylinder. An auxiliary cylinder throttling element is provided on the auxiliary cylinder, and a high-pressure gas storage chamber A is provided on the outside of the auxiliary cylinder. The high-pressure gas storage chamber A is connected to the compression chamber of the auxiliary piston compression system, and the high-pressure gas storage chamber B is connected to the high-pressure gas storage chamber A through an internal connecting pipe.

3. A linear Stirling refrigerator according to claim 2, characterized in that: The high-pressure gas storage chamber B is formed by the main cylinder and the compressor housing; the high-pressure gas storage chamber A is formed by the auxiliary cylinder and the compressor housing.

4. A linear Stirling refrigerator according to claim 2, characterized in that: The front end of the auxiliary piston is provided with an intake port, and an intake valve is provided on the intake port. The front end of the auxiliary cylinder is provided with an exhaust port, and an exhaust valve is provided on the exhaust port. Through the cooperation of the intake valve and the exhaust valve, the working gas in the auxiliary cylinder is periodically compressed, exhausted, expanded and intakeed. The high-pressure gas generated during the exhaust process is stored in the high-pressure gas storage chamber A as the total gas source for the gas bearing.

5. A linear Stirling refrigerator according to claim 2, characterized in that: The linear motor system includes a column spring A, an outer stator, a motor mover, an inner stator, and an excitation element; one end of the motor mover is fixedly connected to the auxiliary piston, and the other end is fixedly connected to the main piston; the column spring A connects the main piston and the auxiliary piston respectively within the linear compressor housing; the outer stator and the excitation element are arranged around the motor mover and the inner stator.

6. A linear Stirling refrigerator according to claim 2, characterized in that: The diameter of the auxiliary piston is larger than that of the main piston.

7. A linear Stirling refrigerator according to claim 1, characterized in that: The piston compression system of the expander includes an expander cylinder and an expander piston that is slidably disposed in the expander cylinder. The expander cylinder is provided with an expander cylinder throttling element. A high-pressure gas storage chamber C is provided on the outside of the expander cylinder. The high-pressure gas storage chamber C is connected to the compression chamber of the auxiliary piston compression system through a high-pressure connecting pipe.

8. A linear Stirling refrigerator according to claim 1, characterized in that: The expander includes an expansion chamber, a cold accumulator, and a column spring B; the expansion chamber is located above the inner cavity of the expander housing and is connected to the main connecting pipe, and a cold accumulator is installed inside it; the bottom end of the cold accumulator is connected to the top end of the expander piston, and the bottom end of the expander piston is connected to the bottom of the inner cavity of the expander housing through the column spring B.

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