A two-stage linear compressor

Abstract

The application provides a two-stage linear compressor, which comprises a shell, a moving-magnet linear motor, a first-stage compression assembly and a second-stage compression assembly; the shell has a containing cavity, an air inlet and an air outlet; the moving-magnet linear motor comprises a stator and a mover; the first-stage compression assembly and the second-stage compression assembly are coaxially arranged in the containing cavity; the first-stage compression assembly comprises a first piston, a first cylinder and a first exhaust valve; one end of a first suction passage is communicated with the air inlet, and the other end is communicated with the containing cavity through the first exhaust valve; the second-stage compression assembly comprises a second piston, a second cylinder and a second exhaust valve; one end of a second suction passage is communicated with the containing cavity, and the other end is communicated with the air outlet through the second exhaust valve; a suction control valve is arranged in each of the first suction passage and the second suction passage. The two-stage linear compressor has a small axial size, can reduce the leakage amount in a large pressure difference application scenario, reduce the exhaust temperature and improve the compressor performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressor, in particular to a two-stage linear compressor. BACKGROUND

[0002] Linear compressor is a kind of compressor using linear motor as drive, which has the advantages of high efficiency, compact structure, small size, light weight, no or little lubricating oil and excellent variable capacity characteristics. It has been widely used as the main development direction of high-efficiency compressor in small refrigeration equipment, and has attracted more and more attention and research application.

[0003] However, the existing linear compressor can only realize the reciprocating motion of the piston in the cylinder under the cooperation of the moving magnetic type linear motor and the plate spring, and then realize the continuous compression of the gas. It is found in actual application that this kind of linear compressor is prone to gas leakage under large pressure difference, and the exhaust temperature is high, which is not conducive to reducing the energy efficiency ratio of the system; at the same time, the plate spring has a large axial installation size, which also directly leads to the problem of excessive axial size of the linear compressor. SUMMARY

[0004] The present application provides a two-stage linear compressor to at least solve the problem of excessive axial size of the existing linear compressor and easy leakage under large pressure difference.

[0005] The present application provides a two-stage linear compressor, comprising: a housing, a moving magnetic type linear motor, a first stage compression assembly and a second stage compression assembly;

[0006] The housing has a receiving cavity, and an air inlet and an air outlet communicating with the receiving cavity;

[0007] The moving magnetic type linear motor comprises a stator and a mover, the stator is connected with the housing, and the mover is arranged in the receiving cavity and can reciprocate relative to the stator; the first stage compression assembly and the second stage compression assembly are coaxially arranged in the receiving cavity;

[0008] The first stage compression assembly comprises a first piston, a first cylinder and a first exhaust valve, the first cylinder is connected with the mover, one end of the first piston is connected with the housing, and the other end is arranged in the movable first cylinder; a first suction passage is arranged in the first piston, one end of the first suction passage is communicated with the air inlet, and the other end is communicated with the receiving cavity through the first exhaust valve;

[0009] The second-stage compression assembly comprises a second piston, a second cylinder and a second exhaust valve, the second cylinder is connected with the shell, one end of the second piston is connected with the mover, and the other end is movably arranged in the second cylinder fixedly arranged; a second suction passage is arranged in the second piston, one end of the second suction passage is communicated with the containing cavity, and the other end is communicated with the exhaust port through the second exhaust valve.

[0010] According to the two-stage linear compressor provided by the application, the first piston and the first exhaust valve define a first cavity in the first cylinder, and the second piston and the second exhaust valve define a second cavity in the second cylinder.

[0011] The mover can reciprocate relative to the stator in a first direction and a second direction, and the first direction and the second direction are opposite.

[0012] In the case that the mover moves in the first direction, the volume of the first cavity increases, the volume of the second cavity decreases, the gas outside enters the first cavity through the first suction passage, and the gas in the second cavity is compressed.

[0013] In the case that the mover moves in the second direction, the volume of the first cavity decreases, the volume of the second cavity increases, the gas in the first cavity is compressed, and the gas in the containing cavity enters the second cavity through the second suction passage.

[0014] According to the two-stage linear compressor provided by the application, the stator comprises an inner stator and an outer stator, the inner stator and the outer stator are coaxially arranged, and a cylindrical air gap is formed between the inner stator and the outer stator.

[0015] The mover comprises a mover framework and an annular permanent magnet, the annular permanent magnet is arranged on the mover framework, the annular permanent magnet is movably arranged in the cylindrical air gap, and the first cylinder and the second piston are respectively connected with the mover framework.

[0016] According to the two-stage linear compressor provided by the application, the inner stator and the outer stator are both configured to comprise a core, and the core is in a cylindrical shape.

[0017] The outer side wall of the core of the inner stator or the inner side wall of the core of the outer stator is provided with excitation coils arranged in a circumferential direction, and the magnetic poles of the annular permanent magnet are arranged in a radial direction.

[0018] According to the two-stage linear compressor provided by the application, the inner stator and the outer stator are both configured to comprise a core, and the core is in a cylindrical shape.

[0019] The inner side of the core of the outer stator is provided with a plurality of projections arranged along the circumference, and each of the projections is wound with an excitation coil;

[0020] The mover comprises two groups of coaxially connected annular permanent magnets, and the magnetic poles of the two groups of annular permanent magnets are arranged in the radial direction and the arrangement directions are opposite.

[0021] According to the double-stage linear compressor provided by the application, the mover is cylindrical, and at least part of the first-stage compression assembly and at least part of the second-stage compression assembly are arranged on the inner side of the mover.

[0022] According to the double-stage linear compressor provided by the application, the first suction passage and the second suction passage are both provided with a suction silencer and a suction control valve.

[0023] According to the double-stage linear compressor provided by the application, the double-stage linear compressor further comprises a cooling assembly.

[0024] The cooling assembly is arranged on the surface of the shell, and at least part of the cooling assembly is arranged at a position opposite to the position of the accommodating cavity, so as to cool the gas in the accommodating cavity.

[0025] According to the double-stage linear compressor provided by the application, at least one of the first cylinder and the first piston is provided with a first venting structure, so that a gas film support is formed between the first cylinder and the first piston; at least one of the second cylinder and the second piston is provided with a second venting structure, so that a gas film support is formed between the second cylinder and the second piston.

[0026] Alternatively, the first cylinder is provided with a first oil guide channel, one end of the first oil guide channel is used for being communicated with an oil pump, and the other end is communicated with the inner cavity of the first cylinder, so that an oil film support is formed between the first cylinder and the first piston; the second cylinder is provided with a second oil guide channel, one end of the second oil guide channel is used for being communicated with an oil pump, and the other end is communicated with the inner cavity of the second cylinder, so that an oil film support is formed between the second cylinder and the second piston.

[0027] According to the double-stage linear compressor provided by the application, the surfaces of the first piston and the second piston are coated with a wear-resistant self-lubricating coating.

[0028] The wear-resistant self-lubricating coating comprises any one of a graphite-like coating, a polyether ether copper coating, a polyimide resin coating, a diamond-like coating, a Teflon coating, a molybdenum disulfide coating, a tungsten disulfide coating, a graphite coating, a chromium nitride coating, a titanium aluminum silicon nitride coating, a titanium aluminum nitride coating, a titanium nitride coating, an aluminum oxide ceramic coating and a phosphating coating.

[0029] The double-stage linear compressor provided by the application can control the working states of the first-stage compression assembly and the second-stage compression assembly by one moving-magnetic linear motor, and when one of the first-stage compression assembly and the second-stage compression assembly is in the suction state, the other one is in the compression state under the driving of the mover of the moving-magnetic linear motor, and the working states of the two are just opposite, which not only ensures that the gas can pass through the first-stage compression assembly and the second-stage compression assembly in sequence and be compressed by the first-stage compression assembly and the second-stage compression assembly in two compression stages, but also can buffer the reciprocating motion of the mover to some extent, and then the plate spring as an energy storage element is no longer needed to help resonance, and compared with the existing linear compressor, the double-stage linear compressor can greatly reduce the axial design size.

[0030] At the same time, since the double-stage linear compressor realizes double-stage compression of the gas based on the first-stage compression assembly and the second-stage compression assembly, in the application scenario of large pressure difference, the double-stage linear compressor can reduce the pressure difference corresponding to each compression stage, thereby reducing the leakage amount and realizing the improvement of the compressor performance.

[0031] In addition, in actual application, the double-stage compression setting based on the double-stage linear compressor is convenient for cooling the gas between the two compression stages, thereby reducing the exhaust temperature of the double-stage linear compressor, and then realizing the reduction of the energy efficiency ratio of the system. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0033] Figure 1 is one of the structural schematic diagrams of the double-stage linear compressor provided by the application;

[0034] Figure 2 is the side view structural schematic diagram of the double-stage linear compressor provided by the application; Figure 1

[0035] Figure 3 is the A-A view of the double-stage linear compressor provided by the application; Figure 2

[0036] Figure 4 is the second structural schematic diagram of the double-stage linear compressor provided by the application;

[0037] ​​Figure 5 is provided by the present application Figure 4 is provided by the present application

[0038] Reference signs:

[0039] 1, housing; 11, accommodating cavity; 12, air inlet; 13, air outlet;

[0040] 2, moving-magnet linear motor; 21, stator; 22, mover; 211, inner stator; 212, outer stator; 221, mover skeleton; 222, annular permanent magnet;

[0041] 3, first-stage compression assembly; 31, first piston; 32, first cylinder; 33, first exhaust valve; 311, first suction passage; 301, first cavity;

[0042] 4, second-stage compression assembly; 41, second piston; 42, second cylinder; 43, second exhaust valve; 411, second suction passage; 401, second cavity;

[0043] 5, cooling assembly. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described below in connection with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0045] The present application will be described below in connection with Figures 1-5 The two-stage linear compressor provided by the embodiments of the present application will be described in detail through specific embodiments and application scenarios.

[0046] As shown in Figures 1 to 3 , the present application provides a two-stage linear compressor, comprising: a housing 1, a moving-magnet linear motor 2, a first-stage compression assembly 3 and a second-stage compression assembly 4.

[0047] The housing 1 has an accommodating cavity 11, and an air inlet 12 and an air outlet 13 which are in communication with the accommodating cavity 11.

[0048] The moving-magnet linear motor 2 comprises a stator 21 and a mover 22, the stator 21 is connected with the housing 1, the stator 21 is in a cylindrical shape, the mover 22 is arranged in the accommodating cavity 11 and located at the inner side of the stator 21, and the mover 22 is capable of reciprocating relative to the stator 21 along the axial direction of the stator 21. The first-stage compression assembly 3 and the second-stage compression assembly 4 are coaxially arranged in the accommodating cavity 11.

[0049] The first-stage compression assembly 3 comprises a first piston 31, a first cylinder 32 and a first exhaust valve 33. The first cylinder 32 is connected with the mover 22, and one end of the first piston 31 is connected with the housing 1 and the other end is movably arranged in the first cylinder 32. The first piston 31 is provided with a first suction passage 311, one end of which is communicated with the air inlet 12 and the other end is communicated with the containing cavity 11 through the first exhaust valve 33. The first exhaust valve 33 is in a cut-off state when the air pressure is lower than the first set pressure and is in a conductive state when the air pressure is higher than the first set pressure.

[0050] The second-stage compression assembly 4 comprises a second piston 41, a second cylinder 42 and a second exhaust valve 43. The second cylinder 42 is connected with the housing 1, and one end of the second piston 41 is connected with the mover 22 and the other end is movably arranged in the second cylinder 42. The second piston 41 is provided with a second suction passage 411, one end of which is communicated with the containing cavity 11 and the other end is communicated with the air outlet 13 through the second exhaust valve 43. The second exhaust valve 43 is in a cut-off state when the air pressure is lower than the second set pressure and is in a conductive state when the air pressure is higher than the second set pressure.

[0051] It can be understood that the housing 1 of the two-stage linear compressor can be configured in a columnar shape, and the moving-magnetic linear motor 2, the first-stage compression assembly 3 and the second-stage compression assembly 4 are arranged along the axial direction of the housing 1.

[0052] The air inlet 12 is arranged at the first end of the housing 1, and the air outlet 13 is arranged at the second end of the housing 1. Both the air inlet 12 and the air outlet 13 can be arranged along the axial direction of the housing 1.

[0053] The first-stage compression assembly 3 can be arranged in the containing cavity 11 close to the air inlet 12, and the second-stage compression assembly 4 can be arranged in the containing cavity 11 close to the air outlet 13.

[0054] In the first-stage compression assembly 3, the first suction passage 311 can be arranged along the axial direction of the first piston 31. One end of the first suction passage 311 close to the air inlet 12 is an inlet end, and the other end of the first suction passage 311 close to the air outlet 13 is an outlet end. The first suction passage 311 only allows the gas to flow from the inlet end to the outlet end.

[0055] Correspondingly, in the second-stage compression assembly 4, the second suction passage 411 can be arranged along the axial direction of the second piston 41. One end of the second suction passage 411 close to the air inlet 12 is an inlet end, and the other end of the second suction passage 411 close to the air outlet 13 is an outlet end. The second suction passage 411 only allows the gas to flow from the inlet end to the outlet end.

[0056] The two-stage linear compressor provided in this embodiment of the invention, by configuring a moving magnet linear motor 2, a first-stage compression assembly 3, and a second-stage compression assembly 4 based on the housing 1, can simultaneously control the working state of the first-stage compression assembly 3 and the second-stage compression assembly 4 through a single moving magnet linear motor 2. Driven by the mover 22 of the moving magnet linear motor 2, when one of the first-stage compression assembly 3 and the second-stage compression assembly 4 is in the intake state, the other of the first-stage compression assembly 3 and the second-stage compression assembly 4 is in the compression state. The two working states are exactly opposite, which not only ensures that the gas can pass through the first-stage compression assembly 3 and the second-stage compression assembly 4 in sequence, and achieve continuous compression of the gas by the first-stage compression assembly 3 and the second-stage compression assembly 4, but also buffers the reciprocating motion of the mover 22 to a certain extent. Therefore, it is no longer necessary to set a leaf spring as an energy storage element to help resonance. Compared with the existing linear compressors, this two-stage linear compressor can significantly reduce the axial design size.

[0057] Meanwhile, since the two-stage linear compressor achieves two-stage compression of gas based on the first-stage compression component 3 and the second-stage compression component 4, in application scenarios with large pressure differentials, the two-stage linear compressor can reduce the pressure differential corresponding to each compression stage, thereby reducing leakage and improving compressor performance.

[0058] In addition, in practical applications, the two-stage compression setting based on the two-stage linear compressor facilitates the cooling of the gas between the two compression stages, thereby reducing the exhaust temperature of the two-stage linear compressor and thus reducing the system's energy efficiency ratio.

[0059] In some embodiments, such as Figure 3 As shown, the first piston 31 and the first exhaust valve 33 define a first cavity 301 within the first cylinder 32, and the second piston 41 and the second exhaust valve 43 define a second cavity 401 within the second cylinder 42.

[0060] The mover 22 can reciprocate relative to the stator 21 along a first direction and a second direction, the first direction and the second direction being opposite.

[0061] When the mover 22 moves along the first direction, the mover 22 drives the first cylinder 32 of the first-stage compression assembly 3 to move relative to the first piston 31 along the first direction, increasing the volume of the first chamber 301. At this time, the first-stage compression assembly 3 is in the intake state, and external gas enters the first chamber 301 through the first intake channel 311. Since the gas pressure in the first chamber 301 is less than the first set pressure, the first exhaust valve 33 is in the closed state, and the first-stage compression assembly 3 stores gas based on the first chamber 301.

[0062] At the same time, as the mover 22 drives the second piston 41 of the second stage compression assembly 4 to move relative to the second cylinder 42 in the first direction, the volume of the second chamber 401 decreases. At this time, the second stage compression assembly 4 is in a compressed state, and the gas in the second chamber 401 is compressed. Only when the gas pressure in the second chamber 401 is greater than the second set pressure will the second exhaust valve 43 be in a conducting state, so that the compressed gas in the second chamber 401 is discharged from the exhaust port 13.

[0063] When the mover 22 moves along the second direction, the mover 22 drives the first cylinder 32 of the first stage compression assembly 3 to move relative to the first piston 31 along the second direction, and the volume of the first cavity 301 decreases. At this time, the first stage compression assembly 3 is in a compression state, and the gas in the first cavity 301 is compressed. Only when the gas pressure in the first cavity 301 is greater than the first set pressure will the first exhaust valve 33 be in a conducting state, so that the compressed gas in the first cavity 301 enters the receiving cavity 11 from the first cavity 301.

[0064] Meanwhile, as the mover 22 drives the second piston 41 of the second-stage compression assembly 4 to move relative to the second cylinder 42 in the second direction, the volume of the second chamber 401 increases. At this time, the second-stage compression assembly 4 is in the intake state, and the gas in the receiving chamber 11 enters the second chamber 401 through the second intake channel 411. Since the gas pressure in the second chamber 401 is less than the second set pressure, the second exhaust valve 43 is in the closed state, and the second-stage compression assembly 4 stores gas based on the second chamber 401.

[0065] As can be seen, as the mover 22 reciprocates relative to the stator 21 along the first and second directions, both the first-stage compression assembly 3 and the second-stage compression assembly 4 switch between the intake state and the compression state. However, the first-stage compression assembly 3 and the second-stage compression assembly 4 are in opposite states at the same time, which enables the bipolar linear compressor to achieve continuous compression of the gas in two compression stages based on the first-stage compression assembly 3 and the second-stage compression assembly 4.

[0066] In some embodiments, such as Figure 3 As shown, the stator 21 includes an inner stator 211 and an outer stator 212, which are coaxially arranged, and a cylindrical air gap is formed between the inner stator 211 and the outer stator 212.

[0067] The mover 22 includes a mover frame 221 and an annular permanent magnet. The annular permanent magnet is disposed on the mover frame 221 and is movably disposed in a cylindrical air gap. The first cylinder 32 and the second piston 41 are respectively connected to the mover frame 221.

[0068] like Figure 3As shown, in order to ensure the compactness of the structure of the two-stage linear compressor, the mover 22 can be provided in a cylindrical shape, and at least part of the first-stage compression assembly 3 and at least part of the second-stage compression assembly 4 are arranged on the inner side of the mover 22.

[0069] Specifically, the mover skeleton 221 can be configured in a cylindrical shape, and the mover skeleton 221 and the annular permanent magnet are coaxially arranged, the first cylinder 32 and the second piston 41 are arranged on the inner side of the mover skeleton 221, and the peripheral wall of the first cylinder 32 can be connected to the inner wall of the mover skeleton 221 through a plurality of first connecting portions arranged in the circumferential direction, and the peripheral wall of the second piston 41 can also be connected to the inner wall of the mover skeleton 221 through a plurality of second connecting portions arranged in the circumferential direction, so as to ensure that the mover 22 can stably and reliably drive the first cylinder 32 and the second piston 41 to reciprocate in the first direction and the second direction.

[0070] In some embodiments, as shown in Figure 3 As shown, the inner stator 211 and the outer stator 212 are both configured to include a core, and the core is in a cylindrical shape and can be formed by stacking a plurality of silicon steel sheets.

[0071] The outer side wall of the core of the inner stator 211 or the inner side wall of the core of the outer stator 212 is provided with an excitation coil arranged in the circumferential direction, and the magnetic poles of the annular permanent magnet are arranged in the radial direction.

[0072] As shown in Figure 3 As shown in the embodiment, the excitation coil arranged in the circumferential direction is arranged on the core of the outer stator 212, and the inner stator 211 is provided in a pure core structure. Of course, the excitation coil arranged in the circumferential direction can also be arranged on the outer side wall of the core of the inner stator 211, and the outer stator 212 is provided in a pure core structure, which is not limited herein.

[0073] Correspondingly, the mover 22 includes a group of annular permanent magnets, and the magnetic poles of the annular permanent magnets are arranged in the radial direction, that is, the magnetic poles on the inner side of the annular permanent magnet are N poles, and the magnetic poles on the outer side are S poles, or the magnetic poles on the inner side of the annular permanent magnet are S poles, and the magnetic poles on the outer side are N poles, which is not limited herein. The annular permanent magnet can be an integral structure, or a plurality of tile-shaped magnets arranged in the circumferential direction connected by a shaping material.

[0074] In some embodiments, the inner stator 211 and the outer stator 212 are both configured to include a core, and the core is in a cylindrical shape. The inner side of the core of the outer stator 212 is provided with a plurality of protrusions arranged in the circumferential direction, and each protrusion is wound with an excitation coil. For example, the inner side of the core of the outer stator 212 can be provided with eight protrusions arranged in the circumferential direction, and the eight protrusions are one-to-one corresponding to eight excitation coils.

[0075] Further, the mover 22 includes two groups of annular permanent magnets connected coaxially, and the magnetic poles of the two groups of annular permanent magnets are both arranged in the radial direction and opposite in direction.

[0076] In one example, the magnetic poles of the inner side of one group of annular permanent magnets are set as N poles, and the magnetic poles of the outer side are set as S poles. Correspondingly, the magnetic poles of the inner side of the other group of annular permanent magnets are set as S poles, and the magnetic poles of the outer side are set as N poles. Each group of annular permanent magnets can be an integrated structure, or can be a plurality of tile-shaped magnets arranged in the circumferential direction and connected by a shaped material, which is not specifically limited here.

[0077] In some embodiments, the first suction passage 311 and the second suction passage 411 are each provided with a suction silencer and a suction control valve.

[0078] Specifically, the first suction passage 311 and the second suction passage 411 can be configured in the same structure, and the outlet end of the first suction passage 311 and the outlet end of the second suction passage 411 are each provided with a suction control valve, which can be a reed valve.

[0079] The suction silencer can be made of foamed metal and is a columnar body with a central axial hole. The outer sidewall of the suction silencer is formed by alternately arranging a convex portion and a concave portion. A plurality of groups of air holes are arranged in the axial direction on the sidewall of the suction silencer, and the air holes in each group are arranged in the circumferential direction. Thus, the noise generated by the linear compressor during the suction process can be effectively eliminated by the suction silencer.

[0080] In actual application, when the first-stage compression assembly 3 is in the suction state, the suction control valve arranged at the outlet end of the first suction passage 311 is in the open state, and the first exhaust valve 33 is in the cutoff state. When the first-stage compression assembly 3 is in the compression state, the suction control valve arranged at the outlet end of the first suction passage 311 is in the closed state, and the first exhaust valve 33 is in the cutoff state. Only when the air pressure in the first cavity 301 is greater than the first set pressure, the first exhaust valve 33 is in the conductive state.

[0081] Correspondingly, when the second-stage compression assembly 4 is in the suction state, the suction control valve arranged at the outlet end of the second suction passage 411 is in the open state, and the second exhaust valve 43 is in the cutoff state. When the second-stage compression assembly 4 is in the compression state, the suction control valve arranged at the outlet end of the second suction passage 411 is in the closed state, and the second exhaust valve 43 is in the cutoff state. Only when the air pressure in the second cavity 401 is greater than the second set pressure, the second exhaust valve 43 is in the conductive state.

[0082] In some embodiments, as shown in FIG. 6, the first suction passage 311 and the second suction passage 411 are each provided with a suction silencer and a suction control valve. Figure 4 and Figure 5As shown, the two-stage linear compressor is further configured with a cooling assembly 5. The cooling assembly 5 is arranged on the surface of the shell 1, and at least part of the cooling assembly 5 is arranged opposite to the position where the accommodating cavity 11 is located, so as to cool the gas in the accommodating cavity 11.

[0083] It can be understood that the shell 1 can be made of copper, aluminum or other materials with high thermal conductivity. The gas in the accommodating cavity 11 can exchange heat with the cooling assembly 5 through the shell 1, so as to achieve cooling. Based on the cooling of the gas in the accommodating cavity 11, the exhaust temperature of the two-stage linear compressor can be reduced, and the system energy efficiency ratio can be reduced.

[0084] As shown in Figure 4 and Figure 5 The cooling assembly 5 can be configured as a cooling coil, which is wound on the peripheral wall of the shell 1 along a spiral trajectory relative to the central axis of the shell 1.

[0085] In some examples, the cooling coil can be used as part of an air conditioning and refrigeration system. For example, the compressor, the condenser, the throttle valve and the cooling coil can be connected in series to form an air conditioning and refrigeration system.

[0086] In some examples, the cooling coil can also be connected with a circulating pump to form a cooling loop, and the medium flowing in the cooling coil can be ice brine or ice water.

[0087] In some embodiments, at least one of the first cylinder 32 and the first piston 31 is provided with a first vent structure to form a gas film support between the first cylinder 32 and the first piston 31; at least one of the second cylinder 42 and the second piston 41 is provided with a second vent structure to form a gas film support between the second cylinder 42 and the second piston 41.

[0088] Specifically, the first vent structure and the second vent structure each include a gas passage and a gas bearing sleeve, and the gas passage and the gas bearing sleeve are in communication. The gas passage corresponding to the first vent structure is arranged in the shell wall of the first cylinder 32, and the first piston 31 is movably arranged in the gas bearing sleeve corresponding to the first vent structure. The gas passage corresponding to the second vent structure is arranged in the shell wall of the second cylinder 42, and the second piston 41 is movably arranged in the gas bearing sleeve corresponding to the second vent structure.

[0089] The gas bearing sleeve can be made of a porous material, which can uniformly provide the outer side wall of the corresponding first piston 31 or second piston 41 with radial pneumatic floating support when the gas bearing sleeve is ventilated through the gas passage, which can greatly reduce the contact sliding friction between the first cylinder 32 and the first piston 31 and between the second cylinder 42 and the second piston 41, and even realize the contactless reciprocating movement of the first piston 31 or the second piston 41, so as to achieve the purpose of oil-free lubrication.

[0090] The porous material has a pore size of 0.1 microns to 1000 microns and is made of metal powder such as iron, aluminum, and copper or metal wire mesh such as iron, aluminum, and copper or non-metallic powder such as carbon powder, graphite powder, silicon dioxide powder, and engineering plastic powder.

[0091] In some embodiments, the first oil guide channel is provided in the first cylinder 32, one end of the first oil guide channel is used to communicate with the oil pump, the other end communicates with the inner cavity of the first cylinder 32, so that the oil film support is formed between the first cylinder 32 and the first piston 31; the second oil guide channel is provided in the second cylinder 42, one end of the second oil guide channel is used to communicate with the oil pump, the other end communicates with the inner cavity of the second cylinder 42, so that the oil film support is formed between the second cylinder 42 and the second piston 41.

[0092] Specifically, in actual application, the first oil guide channel and the second oil guide channel can be filled with lubricating oil of a predetermined pressure through the oil pump, the lubricating oil enters the gap between the first cylinder 32 and the first piston 31 along the first oil guide channel, and enters the gap between the second cylinder 42 and the second piston 41 along the second oil guide channel, so as to achieve the effect of oil film support.

[0093] Similar to the above-mentioned gas film support, the oil film support of the present embodiment can also uniformly provide better radial support for the outer side wall of the first piston 31 or the second piston 41, which can greatly reduce the contact sliding friction generated during the movement of the first piston 31 or the second piston 41, and further ensure the service life of the compressor.

[0094] In some embodiments, the surfaces of the first piston 31 and the second piston 41 corresponding to the dual-stage linear compressor are coated with a wear-resistant self-lubricating coating.

[0095] The surfaces of the first piston 31 and the second piston 41 can be coated with a wear-resistant self-lubricating coating to ensure their respective working performance.

[0096] The wear-resistant self-lubricating coating includes any one of a graphite-like coating (GLC), a polyether ether copper coating (PEEK), a polyimide resin coating (PI), a diamond-like coating (DLC), a Teflon coating, a molybdenum disulfide coating (MoS2), a tungsten disulfide coating (WS2), a graphite coating (C), a chromium nitride coating (CRN), a titanium aluminum silicon nitride coating (TiAlSiN), an aluminum titanium nitride coating (AlTiN), a titanium nitride coating (TiN), an aluminum oxide ceramic coating (Al2O3), and a phosphating coating (P).

[0097] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art will understand that they can modify the technical solutions described in the foregoing examples, or make equivalent replacements for some of the technical features; and these modifications or replacements 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 application.

Claims

1. A two-stage linear compressor, characterized in that, include: Housing, moving magnet linear motor, first-stage compression assembly, and second-stage compression assembly; The housing has a receiving cavity and an air inlet and an air outlet communicating with the receiving cavity; The moving magnet linear motor includes a stator and a mover. The stator is connected to the housing, and the mover is disposed in the receiving cavity. The mover can reciprocate relative to the stator. The first-stage compression assembly and the second-stage compression assembly are coaxially disposed in the receiving cavity. The first-stage compression assembly includes a first piston, a first cylinder, and a first exhaust valve. The first cylinder is connected to the mover. One end of the first piston is connected to the housing, and the other end is located inside the movable first cylinder. The first piston is provided with a first intake channel. One end of the first intake channel is connected to the air inlet, and the other end is connected to the receiving cavity through the first exhaust valve. The second-stage compression assembly includes a second piston, a second cylinder, and a second exhaust valve. The second cylinder is connected to the housing. One end of the second piston is connected to the moving part, and the other end is movably disposed in the fixedly disposed second cylinder. The second piston is provided with a second intake channel. One end of the second intake channel is connected to the receiving cavity, and the other end is connected to the exhaust port through the second exhaust valve. The stator includes an inner stator and an outer stator, which are coaxially arranged and form a cylindrical air gap between them; the mover includes a mover frame and an annular permanent magnet, which is disposed on the mover frame and movably disposed in the cylindrical air gap; the first cylinder and the second piston are respectively connected to the mover frame. The first piston and the first exhaust valve define a first cavity within the first cylinder, and the second piston and the second exhaust valve define a second cavity within the second cylinder; the mover is capable of reciprocating relative to the stator along a first direction and a second direction, wherein the first direction and the second direction are opposite. The two-stage linear compressor does not require a leaf spring as an energy storage element to aid resonance. When the mover moves along the first direction, the volume of the first cavity increases and the volume of the second cavity decreases. External gas enters the first cavity through the first intake channel, and the gas in the second cavity is compressed. When the mover moves along the second direction, the volume of the first cavity decreases, the volume of the second cavity increases, the gas in the first cavity is compressed, and the gas in the receiving cavity enters the second cavity through the second suction channel; Both the inner stator and the outer stator are configured to include an iron core, which is cylindrical; the mover is cylindrical, and at least a portion of the first-stage compression assembly and at least a portion of the second-stage compression assembly are disposed on the inner side of the mover.

2. The two-stage linear compressor according to claim 1, characterized in that, The outer side wall of the inner stator core or the inner side wall of the outer stator core is provided with an excitation coil arranged circumferentially; the magnetic poles of the annular permanent magnet are arranged radially.

3. The two-stage linear compressor according to claim 1, characterized in that, Both the inner stator and the outer stator are configured to include an iron core, which is cylindrical in shape. The inner side of the outer stator core is provided with a plurality of protrusions arranged along the circumference, and an excitation coil is wound on each of the protrusions. The mover includes two sets of coaxially connected annular permanent magnets, the magnetic poles of the two sets of annular permanent magnets are arranged radially and in opposite directions.

4. The two-stage linear compressor according to claim 1, characterized in that, Both the first and second intake channels are equipped with intake silencers, and both the first and second intake channels are equipped with intake control valves.

5. The two-stage linear compressor according to any one of claims 1 to 4, characterized in that, Also includes: Cooling components; The cooling components are disposed on the surface of the housing, and at least a portion of the cooling components are positioned opposite the location of the receiving cavity to cool the gas inside the receiving cavity.

6. The two-stage linear compressor according to any one of claims 1 to 4, characterized in that, At least one of the first cylinder and the first piston is provided with a first venting structure to form an air film support between the first cylinder and the first piston; at least one of the second cylinder and the second piston is provided with a second venting structure to form an air film support between the second cylinder and the second piston. Alternatively, the first cylinder is provided with a first oil guide channel, one end of which is connected to an oil pump and the other end is connected to the inner cavity of the first cylinder, so that an oil film support is formed between the first cylinder and the first piston; the second cylinder is provided with a second oil guide channel, one end of which is connected to an oil pump and the other end is connected to the inner cavity of the second cylinder, so that an oil film support is formed between the second cylinder and the second piston.

7. The two-stage linear compressor according to any one of claims 1 to 4, characterized in that, The surfaces of both the first piston and the second piston are coated with a wear-resistant self-lubricating coating; The wear-resistant self-lubricating coating includes any one of the following: graphite-like coating, polyether ether copper coating, polyimide resin coating, diamond-like coating, Teflon coating, molybdenum disulfide coating, tungsten disulfide coating, graphite coating, chromium nitride coating, titanium aluminum silicon nitride coating, titanium aluminum nitride coating, titanium nitride coating, alumina ceramic coating, and phosphating coating.

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