CN214949897U - Linear oscillation compression type refrigerating machine with double air-floating piston structure - Google Patents

Abstract

The utility model relates to a linear oscillation compression type refrigerator with a double-air-floating piston structure, which comprises a flange-connected linear compressor and an expander, wherein the compression piston body of the linear compressor is in a static pressure air-floating structure, the reciprocating oscillation linear motor is adopted for drive control, a crank mechanism of a crank connecting rod type linear compressor is cancelled, the abrasion of an air cylinder is greatly reduced, and the mechanical conversion efficiency is higher; the ejector of the expansion machine also adopts an air floatation structure, and the ejector piston passes through the center of the compression piston to form linear associated motion with a certain phase difference; the regenerator is of an annular structure, so that the mass of the ejector piston is not influenced by the mass of the regenerative filler, and the convenience of the design of the resonant system is improved.

Description

Linear oscillation compression type refrigerating machine with double air-floating piston structure

Technical Field

The utility model belongs to the technical field of backheating formula cryogenic refrigerator technique and specifically relates to indicate a straight line oscillation compression refrigerator of two air supporting piston structures.

Background

The small-sized regenerative low-temperature refrigerator has compact structure, high power density per unit mass, high refrigeration efficiency at low temperature, environment-friendly refrigeration working medium and easy adjustment of refrigerating capacity, wherein the low-temperature refrigerator driven by the free piston linear motor eliminates a moving part of a crank connecting rod, and has the advantages of simple structure, low operation noise, low vibration magnitude, long service life, high reliability and the like, thereby having wide application in the fields of aerospace, high-temperature superconduction, infrared detection and biomedicine.

The existing small Stirling cycle refrigerating machine is generally driven by a rotary or crank connecting rod type compressor, and the radial force between a compressor piston and a cylinder causes the compressor to vibrate and generate larger noise; in addition, the clearance seal between the ejector and the expansion cylinder in the expansion machine of the refrigerating machine is worn when the process precision is slightly deviated, so that the refrigerating efficiency is reduced.

The existing Stirling refrigerating machine driven by the rotary type or crank connecting rod type compressor has large vibration noise and short service life.

In addition, the existing linear driving Stirling refrigerator with an air-floating piston structure is mostly designed into an integrated structure of a heat regenerator and an ejector, the difficulty of the design of a rotor mass-spring-damping system is increased, the type of the linear driving Stirling refrigerator with a light and compact structure is the type of the linear driving Stirling refrigerator, when the refrigerating capacity is required to be increased, the mass of the rotor of the ejector piston can be increased due to the increase of regenerative filler in the regenerator, the linear driving Stirling refrigerator cannot operate at high frequency, the power density is greatly limited, and the application of the linear driving Stirling refrigerator in a compact type large refrigerating capacity refrigerator is restricted.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a to prior art not enough, the utility model discloses a two air supporting piston structure's sharp oscillation compression refrigerator.

The utility model discloses the technical scheme who adopts as follows:

a linear oscillation compression type refrigerating machine with a double-air-floating piston structure comprises an expansion machine and a linear compressor which are connected through flanges; the expander comprises a regenerator; the regenerator comprises an annular regenerator housing; an expansion cylinder is arranged in the regenerator shell; an ejector piston with the same axis is arranged in the expansion cylinder; the ejector piston is in clearance fit with the regenerator shell; one end of the ejector piston is an ejector piston sealed cavity with a hollow structure; the exhaust piston sealed cavity is separated from the exhaust piston air-floatation air storage cavity through a sealing block; a gap between the air floatation air storage cavity of the discharge piston and the expansion cylinder is sealed;

the linear compressor comprises a compression cylinder and a power mechanism; the compression cylinder includes a compression piston body; the compression piston body is in clearance sealing contact with the compression cylinder; the other end of the ejector piston passes through the compression piston body; the compression piston body comprises a front air floatation chamber and a rear air floatation chamber; the front air floatation cavity is tightly matched with the compression piston body through an air storage chamber plug at the side of the compression cavity to form a first air storage cavity; the rear air floatation cavity is tightly matched with the compression piston body through an air storage chamber plug at the back pressure cavity side to form a second air storage cavity;

the power mechanism comprises an inner magnetic pole, a permanent magnet, a conductive coil and an outer magnetic pole; the inner magnetic pole and the outer magnetic pole are arranged along the circumferential direction of the central axis and form a magnetic flux loop inside and outside the permanent magnet; the lead coil is fixed in the outer magnetic pole; the permanent magnet is a moving part, the permanent magnet is connected with the compression piston body to form an integral rotor part, a magnetic field generated by the permanent magnet and an alternating magnetic field generated by the lead ring are coupled to each other, and an axial driving force is generated to push the compression piston body to do reciprocating oscillation linear motion in the compression cylinder.

The method is further technically characterized in that: one end of the cold accumulator shell is inserted into the slit cold head, the end face of the expansion cylinder is provided with a plurality of through straight grooves along the circumferential direction of the expansion cylinder, and the slit cold head is communicated with the through straight grooves.

The method is further technically characterized in that: the expansion cylinder is connected with the expansion cylinder sleeve through gluing; and a regenerative material is filled between the regenerator shell and the expansion cylinder sleeve.

The method is further technically characterized in that: the ejector piston includes integrally formed first and second sections; the outer diameter of the first section is greater than the outer diameter of the second section; the first section is connected with the discharge piston bush through gluing; the second section passes through the central axial hole of the compression piston body.

The method is further technically characterized in that: one end of the ejector piston is fixedly connected with the expansion piston plate spring through a fastening element.

The method is further technically characterized in that: and a check valve is arranged in the air floatation air storage cavity of the discharge piston.

The method is further technically characterized in that: slotted screws are arranged in the first air storage cavity and the second air storage cavity respectively along the circumferential inner surfaces of the first air storage cavity and the second air storage cavity.

The method is further technically characterized in that: one end of the compression piston body is provided with a cantilever type plate spring.

The method is further technically characterized in that: the linear compressor further comprises a compressor housing; the compression cylinder and the power mechanism are arranged in the compressor shell; a refrigerator tail cover is arranged on one side of the compressor shell, and the interior of the refrigerator tail cover is communicated with the compressor shell; and the tail cover of the refrigerator is provided with an inflation valve.

The method is further technically characterized in that: a passive vibration damping mechanism is arranged on one side of the refrigerator tail cover; the passive vibration damping mechanism comprises a vibration damping plate spring support fixed on the tail cover of the refrigerator, and a vibration damping part is arranged on the vibration damping plate spring support; the damping component comprises a plurality of damping plate springs and balancing weights which are connected through locking elements; the vibration reduction component is fixedly connected with the refrigerator tail cover through a vibration reduction fastener.

Compared with the prior art, the technical scheme of the utility model have following advantage:

1. double air-float piston structure. The utility model discloses a compression piston body and ejector piston all adopt static pressure air supporting bearing structure, have eccentric self-adaptation regulation's under the piston dynamic operation function, can improve the life-span and the reliability of refrigerator.

2. The annular cold accumulator and the exhaust piston seal air storage cavity structure. The structure is different from the structural form that the regenerator and the discharge piston of the Stirling refrigerator with the existing air-floating piston structure are integrated, the thermodynamic design and the dynamic design are independently separated, and the convenience and the adaptability of the design are improved; meanwhile, the sealed cavity inside the ejector piston discharges air by using lipid volatile glue, so that the cold loss caused by convection heat conduction of air is eliminated.

3. The double air storage cavities compress the piston air-float structure. The compression piston is provided with two static pressure air storage cavities simultaneously, so that radial gas supporting force is distributed more uniformly along the axial direction.

4. And the plate spring group vibration damping structure. The passive vibration damping system adopting the cantilever plate spring assembly and the annular balancing weight combined structure reduces the axial length of the refrigerator and enables the volume of the refrigerator to be more compact.

Drawings

In order to make the content of the invention more clearly understood, the invention will now be described in further detail with reference to specific embodiments thereof, in conjunction with the accompanying drawings, in which

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a front view of the present invention.

Fig. 3 is a cross-sectional view of the present invention.

Fig. 4 is a schematic view of the working principle of the present invention.

The specification reference numbers indicate: 1. a slit cold head; 2. a regenerator housing; 3. an expansion cylinder sleeve; 4. discharging the piston liner; 5. discharging the piston sealed cavity; 6. a sealing block; 7. discharging the piston air-floatation air storage cavity; 8. a check valve; 9. the vacuum chamber is externally connected with a flange; 10. a flange connecting block; 11. a flow guide sieve; 12. an expansion cylinder; 13. a hot end heat dissipation block; 14. a cylinder base; 15. a compression cylinder; 16. an ejector piston; 17. compressing the piston body; 18. a plug of the air storage chamber at the side of the compression cavity; 19. compressing the piston seal sleeve; 20. a plug of the air storage chamber at the side of the back pressure cavity; 21. compressing the piston core ring; 22. a cantilever-type plate spring; 23. a plate spring lock nut; 24. a leaf spring washer; 25. a discharge piston plate spring; 26. an inner magnetic pole; 27. a permanent magnet; 28. a permanent magnet carrier; 29. a conductive coil; 30. an outer magnetic pole; 31. a leaf spring support; 32. a compressor housing; 33. an inflation valve; 34. a refrigerator tail cover; 35. a wire hole; 36. a vibration-damping fastener; 37. a damping plate spring support; 38. a balancing weight; 39. a damper plate spring; 40. and a locking element.

Detailed Description

The present invention is further described with reference to the following drawings and specific embodiments so that those skilled in the art can better understand the present invention and can implement the present invention, but the embodiments are not to be construed as limiting the present invention.

The foregoing and other features, aspects and utilities of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Therefore, the directional terminology used is for the purpose of description and is not intended to be limiting, and moreover, like reference numerals will be used to refer to like elements throughout.

Fig. 1 is a schematic structural diagram of the present invention, fig. 2 is a front view of the present invention, and fig. 3 is a sectional view of the present invention. Referring to fig. 1 to 3, a linear oscillation compression type refrigerator with a double air-floating piston structure includes an expander, a linear compressor, a passive vibration damping mechanism and a supporting mechanism. The expander and the linear compressor are flanged. The expander includes a regenerator. The regenerator comprises an annular regenerator shell 2, and a vacuum chamber external flange 9 is sleeved on the outer wall of the regenerator shell 2. The regenerator housing 2 is made of stainless steel.

The supporting mechanism comprises an air cylinder base 14, the vacuum chamber external flange 9 is connected with the air cylinder base 14 through a flange connecting block 10 and a hot end heat dissipation block 13, and a flow guide sieve 11 is arranged between the vacuum chamber external flange 9 and the air cylinder base 14. The diversion screen 11 is provided with a plurality of first through holes.

The slit cold head 1 is inserted into the regenerator housing 2 and is brazed and sealed at the periphery, specifically, the slit cold head 1 is made of red copper, a plurality of straight grooves are machined in the slit cold head 1 through linear cutting, then the slit cold head is inserted into the regenerator housing 2 made of stainless steel, and the slit cold head 1 is brazed and sealed at the periphery. In this embodiment, 32 straight grooves with a width of 0.35mm are processed inside the slit cold head 1 by wire cutting.

The expansion cylinder 12 is connected with the expansion cylinder sleeve 3 through gluing, and the expansion cylinder sleeve 3 is made of stainless steel. In this embodiment, the expansion cylinder 12 and the expansion cylinder sleeve 3 are adhesively connected by clear water sample epoxy resin glue.

A heat regeneration material with larger volumetric heat capacity is filled between the regenerator shell 2 and the expansion cylinder sleeve 3, the heat regeneration material is filled with random fibers, and the random fibers are stainless steel wool or PC (polycarbonate) or polypropylene fibers, so that the labor cost in the assembly process is greatly reduced. In this embodiment, stainless steel wool with a porosity of 0.65 is filled between the regenerator housing 2 and the expansion cylinder sleeve 3.

A plurality of straight grooves are formed in one end of the expansion cylinder 12 along the circumferential direction, and the expansion cylinder 12 is made of stainless steel. In this embodiment, 96 straight grooves with a width of 0.4mm are machined at one end of the expansion cylinder 12 along the circumferential direction.

A coaxial ejector piston 16 is disposed within the expansion cylinder 12. The discharge piston 16 is made of an aluminum alloy and coated with diamond powder on the surface to enhance hardness and wear resistance. The ejector piston 16 is clearance fitted to the regenerator housing 2. One end of the ejector piston 16 is an ejector piston closed cavity 5 with a hollow structure. The discharge piston closed cavity 5 is separated from the discharge piston air-floatation air storage cavity 7 through a sealing block 6, and volatile lipid glue is filled in the discharge piston closed cavity 5 to discharge residual air. And a gap between the discharge piston air-flotation air storage cavity 7 and the expansion cylinder 12 is sealed, and specifically, the discharge piston air-flotation air storage cavity 7 and the expansion cylinder 12 are communicated through a screw with a fine through hole as a small-hole throttle valve. A check valve 8 is arranged in the air-floatation air storage cavity 7 of the discharge piston.

The gas in the air-floating gas storage cavity 7 of the discharge piston can be communicated with the gas in the first gas storage cavity and the second gas storage cavity, and a check valve 8 is arranged. When the external pressure of the check valve 8 is very high, the gas in the first gas storage cavity and the second gas storage cavity can jack the check valve 8, and at the moment, the gas is inflated into the air floatation gas storage cavity 7 of the discharge piston; when the pressure of the gas in the discharge piston air-flotation gas storage cavity 7 is higher than the pressure in the compression cavity, the check valve 8 is closed, so that sufficient pressure in the discharge piston air-flotation gas storage cavity 7 can be ensured, then only flow closure is carried out from the middle of the radial small-hole throttle valve, and then a radial gas supporting force is generated to maintain the compression piston body 17 to return to the center from eccentricity.

The ejector piston 16 includes integrally formed first and second sections. The first section has an outer diameter greater than an outer diameter of the second section. The first section is connected with the discharge piston bush 4 through gluing, and the material of the discharge piston bush 4 is PVC engineering plastic. The second section passes through the central axial hole of the compression piston body 17.

One end of the ejector piston 16 is fixedly connected to the ejector piston plate spring 25 by means of a fastening element. In the present embodiment, the fastening elements are screws, the thickness of the discharge piston plate spring 25 is 1.5mm, and the hollow-out line of the discharge piston plate spring 25 is an archimedes spiral line.

The linear compressor includes a compression cylinder 15 and a power mechanism. The compression cylinder 15 is provided with a plurality of second through holes, and the second through holes correspond to the first through holes on the diversion screen 11 one by one. In this embodiment, twenty second through holes are circumferentially and uniformly distributed on the compression cylinder 15, and correspondingly, twenty first through holes are formed on the diversion screen 11.

The compression cylinder 15 comprises a compression piston body 17. The compression piston body 17 is in gap-sealing contact with the compression cylinder 15. The other end of the ejector piston 16 passes through a compression piston body 17. The compression piston body 17 includes a front air bearing chamber and a rear air bearing chamber. The front air floatation chamber is tightly matched with the compression piston body 17 through a compression chamber side air storage chamber plug 18 to form a first air storage chamber. The rear air floatation chamber is tightly matched with the compression piston body 17 through a back pressure chamber side air storage chamber plug 20 to form a second air storage chamber. Slotted screws are arranged in the first air storage cavity and the second air storage cavity respectively along the circumferential inner surfaces of the first air storage cavity and the second air storage cavity. In this embodiment, four orifices of the slotted screw structure are uniformly distributed along the circumferential inner surfaces of the first air storage cavity and the second air storage cavity, and the orifices of the slotted screw structure are radial air-flotation supporting forces of the first air storage cavity and the second air storage cavity, so that the compression piston body 17 is more uniformly stressed.

One end of the compression piston body 17 is provided with a cantilevered plate spring 22. In this embodiment, the thickness of the cantilever leaf spring 22 is 1 mm. The compression piston body 17 provides restoring force of axial reciprocating oscillation with a cantilever type plate spring 22, and the compression piston body 17 and the cantilever type plate spring 22 are fixedly bolted by a compression piston core ring 21 and a plate spring locking nut 23.

The cantilever plate spring 22 and the displacer plate spring 25 are fixed by peripheral screw connections by means of a plate spring washer 24 of suitable thickness, the thickness of the plate spring washer 24 being determined in combination with the axial maximum travel of the two plate springs, cantilever plate spring 22 and displacer plate spring 25, in order to ensure that no collision interference occurs during operation. In this embodiment, the thickness of the plate spring washer 24 is 10 mm.

The power mechanism comprises an inner magnetic pole 26, a permanent magnet 27, a wire coil 29 and an outer magnetic pole 30. The inner 26 and outer 30 poles are circumferentially disposed along the central axis and form a flux circuit between the interior and exterior of the permanent magnet 27. The permanent magnet 27 is supported by a permanent magnet bracket 28. The coil 29 is fixed in the outer pole 30. The permanent magnet 27 is a moving part, the permanent magnet 27 and the compression piston body 17 are connected to form an integral mover part, and a magnetic field generated by the permanent magnet 27 and an alternating magnetic field generated by the lead coil 29 are coupled to each other to generate an axial driving force to push the compression piston body 17 to perform reciprocating oscillating linear motion in the compression cylinder 15.

The linear compressor is driven by a linear oscillating motor, and a wire coil 29 with a plurality of turns is arranged in the motor and is wound in the circumferential direction; moreover, the eight groups of tile-shaped permanent magnets 27 distributed along the circumferential direction adopt an embedded arrangement structure, so that the permanent magnets 27 have better mechanical strength in the cylindrical permanent magnet bracket 28, and the defect that the permanent magnets of the traditional motor are easy to fall off in a surface-mounted manner is overcome; and adopt inner magnetic pole 26 and outer magnetic pole 30 that arrange along axis circumference to form the magnetic flow return circuit in permanent magnet 27 inside and outside for permanent magnet 27 cuts the magnetic induction line and produces the axial electromagnetic force of cycle alternation in reciprocal linear oscillation process, for the condition that outer magnetic pole 30 adopts the silicon steel sheet, can adopt eight groups of stack technology, correspond with eight groups of tile sheet permanent magnet 27 in proper order, greatly reduced eddy current loss.

The linear compressor also includes a compressor housing 32. The compressor housing 32 houses the compression cylinder 15 and the power mechanism. A refrigerator tail cover 34 is installed at one side of the compressor housing 32, and the inside of the refrigerator tail cover 34 communicates with the compressor housing 32. The refrigerator tail cover 34 is provided with an inflation valve 33, and a closed pressure-bearing space can be provided for the interior of the compressor through the inflation valve 33.

The cantilever type plate spring 22 and the discharge piston plate spring 25 are connected with the outer magnetic pole 30 through a plate spring support 31, the plate spring support 31 is fixed on the cylinder base 14 through long screws uniformly distributed in the circumferential direction, and meanwhile, the outer magnetic pole 30 is pressed tightly, so that the structural stability of the motor is guaranteed.

One side of the refrigerator tail cover 34 is provided with a passive damping mechanism. The passive damping mechanism comprises a damping plate spring support 37 fixed on the refrigerator tail cover 34, and a damping component is arranged on the damping plate spring support 37. The damping means comprise a plurality of damping plate springs 39 and a weight 38 connected by a locking element 40, which locking element 40 may be a long screw. The damping member is fixedly connected to the refrigerator tail cap 34 by a damping fastener 36. The compressor housing 32, the refrigerator tail cover 34, and the cylinder base 14 are hermetically connected by laser welding. The bottom of the refrigerator tail cover 34 is provided with a lead hole 35, and the arrangement of the lead hole 35 is convenient for the circuit routing of the refrigerator. When the refrigerator runs at 60Hz, the passive damping mechanism can exert the optimal damping effect.

Fig. 4 is a schematic view of the working principle of the present invention. The working principle of the utility model is as follows:

1. isothermal compression; in the initial state, the ejector piston 16 and the compression piston body 17 are relatively stationary. When the power mechanism is powered on, the magnetic field generated by the permanent magnet 27 and the alternating magnetic field generated by the wire coil 29 are coupled to each other, an axial driving force is generated to push the compression piston body 17 to move leftwards in the compression cylinder 15, gas in the compression cavity is pressed in the leftward movement process, and the heat of the gas can be timely led out through the hot-end heat dissipation block 13 while the gas is pressed. The high-temperature gas flows along the flow channel between the regenerator shell 2 and the expansion cylinder sleeve 3, and the regenerative material is filled between the regenerator shell 2 and the expansion cylinder sleeve 3, so that the regenerative material can absorb the heat of the high-temperature gas, reduce the temperature of the high-temperature gas and obtain low temperature. Through the deflection screen 11 and into the regenerator.

2. Carrying out constant volume heat release; during the process of continuing compression of the compression piston body 17, the ejector piston 16 will also move due to the pressure increase of the compression chamber in the linear compressor, at this time, the ejector piston 16 and the compression piston body 17 will move together to the left, the chamber body in the regenerator and the ejection piston sealing chamber 5 will maintain a face-lifting state, and at the same time, a heat release process, that is, a heat release process of gas to the regenerative filler, will be performed.

3. Isothermal expansion; at this time, after the compression piston body 17 moves to the left to the extreme position, the compression piston body 17 moves to the right, the phase of the ejector piston 16 lags behind the phase of the compression piston body 17, and the ejector piston 16 continues to move to the left, resulting in a lower gas pressure in the compression chamber. After the cold end of the displacer piston 16 has drawn heat, the gas will flow towards the compression chamber, since at this point the pressure in the expansion chamber at the cold end of the displacer piston 16 is high and the pressure in the compression chamber is low, and the gas will return from the expansion chamber to the compression chamber again.

4. Carrying out isometric heat absorption; the compression piston body 17 continues to move to the right, at which point the ejector piston 16 has reached its extreme position to the left, and the ejector piston 16 is also moved to the right, at which point the direction of movement of the ejector piston 16 and the compression piston body 17 is simultaneously to the right, at which point the compression chamber internal volume is unchanged. After the linear oscillation compression type refrigerator with the double air-floating piston structure produces refrigeration, the heat regeneration material absorbs external heat, the temperature changes, and then the heat returns along the original flow direction from the cold end of the ejector piston 16, when the gas passes through the heat regenerator, the gas is absorbed in the heat regenerator, the heat absorbed by the heat regeneration material of the original heat regenerator is equivalent to the heat release of the gas to the heat regeneration material of the heat regenerator, and then the gas becomes gas when returning, absorbs the heat from the heat regeneration material, realizes the reciprocating heat absorption and heat release processes of the heat regeneration material in the heat regenerator, and then returns to the compression cavity again to complete a cycle.

5. When the isochoric heat absorption process is finished, the compression piston body 17 of the linear compressor returns to the initial equilibrium position just before one cycle, and the ejector piston body 16 also returns to the equilibrium position, and a complete cycle is completed, and then the gas again follows the flow passage between the regenerator housing 2 and the expansion cylinder sleeve 3 for the next cycle.

In the description of the embodiments of the present invention, it should be further noted that unless explicitly stated or limited otherwise, the terms "disposed" and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious changes and modifications can be made without departing from the scope of the invention.

Claims (10)

1. The utility model provides a two air supporting piston structure's straight line oscillation compression refrigerator which characterized in that: the system comprises an expander and a linear compressor which are connected through flanges; the expander comprises a regenerator; the regenerator comprises an annular regenerator housing (2); an expansion cylinder (12) is arranged in the regenerator shell (2); a coaxial ejector piston (16) is arranged in the expansion cylinder (12); the ejector piston (16) and the regenerator housing (2) are in clearance fit; one end of the ejector piston (16) is an ejector piston sealed cavity (5) with a hollow structure; the discharge piston sealed cavity (5) is separated from the discharge piston air-floatation air storage cavity (7) through a sealing block (6); a gap between the exhaust piston air-floatation air storage cavity (7) and the expansion cylinder (12) is sealed;

the linear compressor comprises a compression cylinder (15) and a power mechanism; the compression cylinder (15) comprises a compression piston body (17); -a gap-sealing contact between the compression piston body (17) and the compression cylinder (15); the other end of the ejector piston (16) passes through the compression piston body (17); the compression piston body (17) comprises a front air floatation chamber and a rear air floatation chamber; the front air floatation chamber is tightly matched with the compression piston body (17) through a compression chamber side air storage chamber plug (18) to form a first air storage chamber; the rear air floatation chamber is tightly matched with the compression piston body (17) through an air storage chamber plug (20) at the back pressure chamber side to form a second air storage chamber;

the power mechanism comprises an inner magnetic pole (26), a permanent magnet (27), a wire coil (29) and an outer magnetic pole (30); the inner magnetic pole (26) and the outer magnetic pole (30) are arranged along the circumferential direction of the central axis and form a magnetic flux loop inside and outside the permanent magnet (27); the lead coil (29) is fixed in the outer magnetic pole (30); the permanent magnet (27) is a moving part, the permanent magnet (27) and the compression piston body (17) are connected to form an integral rotor part, a magnetic field generated by the permanent magnet (27) and an alternating magnetic field generated by the conducting coil (29) are mutually coupled to generate an axial driving force to push the compression piston body (17) to do reciprocating oscillation linear motion in the compression cylinder (15).

2. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: one end of the regenerator shell (2) is inserted into the slit cold head (1), a plurality of straight through grooves are formed in the end face of the expansion cylinder (12) along the circumferential direction of the expansion cylinder, and the slit cold head (1) is communicated with the straight through grooves.

3. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: the expansion cylinder (12) is connected with the expansion cylinder sleeve (3) through gluing; and a regenerative material is filled between the regenerator shell (2) and the expansion cylinder sleeve (3).

4. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: the ejector piston (16) comprises a first section and a second section which are integrally formed; the outer diameter of the first section is greater than the outer diameter of the second section; the first section is connected with a discharge piston bushing (4) through gluing; the second section passes through a central axial hole of the compression piston body (17).

5. The linear oscillation compression type refrigerator of a double air floating piston structure according to claim 1 or 4, characterized in that: one end of the ejector piston (16) is fixedly connected to an expansion piston leaf spring (25) by means of a fastening element.

6. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: a check valve (8) is arranged in the air floatation air storage cavity (7) of the discharge piston.

7. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: slotted screws are arranged in the first air storage cavity and the second air storage cavity respectively along the circumferential inner surfaces of the first air storage cavity and the second air storage cavity.

8. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: one end of the compression piston body (17) is provided with a cantilever type plate spring (22).

9. The linear oscillation compression refrigerator of a double air floating piston structure according to claim 1, wherein: the linear compressor further comprises a compressor housing (32); the compressor shell (32) is internally provided with the compression cylinder (15) and the power mechanism; a refrigerator tail cover (34) is arranged on one side of the compressor shell (32), and the interior of the refrigerator tail cover (34) is communicated with the compressor shell (32); and the refrigerator tail cover (34) is provided with an inflation valve (33).

10. A linear oscillation compression type refrigerator of a double air floating piston structure according to claim 9, wherein: a passive vibration damping mechanism is arranged on one side of the refrigerator tail cover (34); the passive vibration damping mechanism comprises a vibration damping plate spring support (37) fixed on a refrigerator tail cover (34), and a vibration damping part is arranged on the vibration damping plate spring support (37); the damping means comprise a plurality of damping plate springs (39) and a counterweight (38) connected by a locking element (40); the vibration reduction component is fixedly connected with the refrigerator tail cover (34) through a vibration reduction fastener (36).

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