A piston and a linear compressor

Abstract

The present invention provides a piston and a linear compressor. The piston includes a piston body, a first air passage, a second air passage, a first air valve, a second air valve, and a pneumatic bushing. An air cavity is formed inside the piston body. The first end of the first air passage and the first end of the second air passage are both communicated with the air cavity. The second end of the first air passage is formed at one end of the piston body, and the second end of the second air passage is formed at the other end of the piston body. The pneumatic bushing is sleeved on the side wall of the piston body. The air cavity is communicated with the inner side surface of the pneumatic bushing, and a plurality of throttle air holes are formed on the side wall of the pneumatic bushing. The present invention realizes the non-contact operation of the piston in the cylinder, greatly reduces the axial dimension of the linear compressor, reduces the clearance leakage generated by the high-pressure gas between the cylinder and the piston, and effectively improves the efficiency of the linear compressor.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular, to a piston and a linear compressor. Background Art

[0002] In the field of cryogenic technology, reciprocating flow refrigerators such as Stirling refrigerators, pulse tube refrigerators, and thermoacoustic refrigerators mainly use the periodic expansion and compression of gases to produce cooling capacity. The compressor of a reciprocating flow refrigerator is mainly a valve-less linear compressor, which is used as a pressure wave generator of the reciprocating flow refrigerator to realize the periodic compression and expansion of gases in the refrigerator. The linear compressor is directly driven by a linear motor to eliminate the crank connecting rod mechanism on the traditional reciprocating piston compressor, reduce the motion conversion device, and greatly improve the efficiency of the compressor, thus receiving extensive attention and application.

[0003] At present, the pressure wave generator of a reciprocating flow refrigerator is widely applied with a moving coil type or a moving magnet type linear oscillating motor. The moving magnet type linear oscillating motor installs a magnetic conductive material on the circumference of an excitation coil to form a magnetic circuit structure of a cylindrical air gap concentric with the excitation coil. The cylindrical stator forms the air gap, and the radially magnetized cylindrical permanent magnet moves reciprocally in the air gap. Therefore, the moving magnet type linear motor has advantages such as small magnetic circuit loss and large specific thrust.

[0004] For a cryogenic valve-less linear compressor driven by a cylindrical linear oscillating motor, most of such linear compressors arrange resonance plate springs on both sides thereof, and the resonance plate springs on both sides provide support for the reciprocating motion of the piston in the cylinder, so that the piston and the cylinder of the linear compressor can run without contact. Since the resonance plate springs are arranged on both sides of the linear compressor, at least an axial space greater than the running distance of the resonance plate springs needs to be reserved on both sides of the linear compressor, which results in a large size of the linear compressor.

[0005] Meanwhile, limited by the processing accuracy of parts and the installation accuracy of workers, in order to ensure that the piston and the cylinder on the linear compressor run completely without contact, the fitting clearance between the cylinder and the piston should be relatively large, resulting in serious gas leakage between the compression chamber and the back pressure chamber of the compressor, and the compression ratio of the refrigerator cannot be further increased. However, if the fitting clearance between the cylinder and the piston is reduced to reduce gas leakage, it will cause difficulties in assembling the linear compressor. Summary of the Invention

[0006] The present invention provides a piston and a linear compressor to solve the problem that the piston in the existing linear compressor can only be supported by the resonance plate springs arranged on both sides of the linear compressor, which affects the size of the linear compressor and is not conducive to improving the compression ratio of the linear compressor.

[0007] The present invention provides a piston, comprising: a piston body, a first air passage, a second air passage, a first air valve, a second air valve and a pneumatic bushing; an air cavity is formed inside the piston body; the first ends of the first air passage and the second air passage are both communicated with the air cavity, the second end of the first air passage is formed at one end of the piston body, and the second end of the second air passage is formed at the other end of the piston body; the first air valve is installed in the first air passage, and the second air valve is installed in the second air passage; the pneumatic bushing is sleeved on the side wall of the piston body, the air cavity is communicated with the inner side surface of the pneumatic bushing, and a plurality of throttle air holes are formed on the side wall of the pneumatic bushing.

[0008] According to a piston provided by the present invention, ventilation holes are formed on the wall surface of the air cavity, the ventilation holes are communicated with the inner side surface of the pneumatic bushing, and the outer side surface of the pneumatic bushing is flush with or higher than the side surface of the piston body.

[0009] According to a piston provided by the present invention, both the first air valve and the second air valve are one-way valves. The first air valve is used to control the air flow to be directed into the air cavity from the first air passage, and the second air valve is used to control the air flow to be directed into the air cavity from the second air passage.

[0010] According to a piston provided by the present invention, the pneumatic bushing and the piston body are coaxially arranged. The throttle air holes extend from the inner side surface to the outer side surface of the pneumatic bushing along the radial direction of the pneumatic bushing, and the aperture of the throttle air holes is 0.001-1000 μm.

[0011] According to a piston provided by the present invention, a connecting seat is formed at the other end of the piston body; and / or, the piston body comprises a first section and a second section; the first section and the second section are coaxially connected; the pneumatic bushing is coaxially sleeved on the side wall of at least one of the first section and the second section.

[0012] The present invention further provides a linear compressor, comprising a housing and a core. The core is disposed in the cavity of the housing. The core comprises a stator, a mover, a leaf spring and a cylinder. The stator, the mover and the cylinder are coaxially arranged. The stator and the mover form a linear motor. The linear compressor further comprises the piston as described above; the piston is slidably installed in the cylinder. A compression cavity is formed between one end of the piston and the wall surface of the first side of the housing, and a back pressure cavity is formed between the other end of the piston and the wall surface of the second side of the housing. An exhaust passage is provided on the housing, and the exhaust passage is communicated with the compression cavity; the other end of the piston and one end of the mover are both connected to the middle of the leaf spring, and the end of the leaf spring is connected to one end of the stator.

[0013] A linear compressor provided according to the present invention, wherein a damping structure is installed in the back pressure chamber, one end of the damping structure is connected to the middle of the leaf spring, and the other end is connected to the housing.

[0014] A linear compressor provided according to the present invention, wherein the damping structure includes a damping spring and a damping block; the damping spring is coaxially arranged with the piston; the damping block is installed in the middle of the damping spring, one end of the damping spring is connected to the middle of the leaf spring, and the other end is connected to the housing.

[0015] A linear compressor provided according to the present invention, wherein one movement mechanism is provided in the housing; alternatively, two movement mechanisms are provided in the housing, the two movement mechanisms are arranged along the axial direction of the piston and are arranged in an opposed manner, and the compression chambers on the two movement mechanisms are both communicated with the exhaust passage; an anti-collision device is installed between the end of the cylinder away from the leaf spring and the housing, and a ventilation passage is configured on the anti-collision device, and the compression chamber is communicated with the exhaust passage through the ventilation passage.

[0016] A linear compressor provided according to the present invention, wherein the stator includes an inner stator and an outer stator, the inner stator and the outer stator are coaxially arranged, one of the inner stator and the outer stator is an iron core, and the other of the inner stator and the outer stator includes an iron core and an excitation winding; the rotor includes a rotor skeleton and a ring permanent magnet; the ring permanent magnet is installed on the rotor skeleton; one end of the rotor skeleton is respectively connected to the middle of the leaf spring and the connection seat on the piston body; the inner stator is coaxially arranged inside the ring permanent magnet, and the outer stator is coaxially arranged outside the ring permanent magnet; a cylindrical air gap is formed between the inner stator and the outer stator, the ring permanent magnet is coaxially disposed inside the cylindrical air gap, or the one of the inner stator and the outer stator that is the iron core is connected to the ring permanent magnet.

[0017] A linear compressor provided according to the present invention, in a case where a cylindrical air gap is formed between the inner stator and the outer stator, the cylindrical air gap is straight along the moving direction of the piston; the exciting winding is circumferentially arranged on the inner stator or the outer stator, the mover includes a set of annular permanent magnets, and the magnetic poles of the annular permanent magnets are arranged radially along the linear compressor; alternatively, a plurality of protrusions arranged circumferentially are provided on the outer side surface of the inner stator or the inner side surface of the outer stator, and the exciting winding is wound around each of the protrusions, the mover includes two sets of coaxially connected annular permanent magnets, and the magnetic poles of the two sets of annular permanent magnets are both arranged radially along the linear compressor and the arranged directions are opposite; alternatively, in a case where a cylindrical air gap is formed between the inner stator and the outer stator, the cores of the inner stator and the outer stator at the end away from the leaf spring are connected so that the end of the cylindrical air gap away from the leaf spring is closed; the exciting winding is circumferentially arranged on the inner stator or the outer stator, the mover includes two sets of coaxially connected annular permanent magnets, and the magnetic poles of the two sets of annular permanent magnets are both arranged radially along the linear compressor and the arranged directions are opposite.

[0018] A piston and a linear compressor provided by the present invention, by providing an air cavity, a first air passage, a second air passage, a first air valve, a second air valve and a pneumatic bushing on the piston body, during the reciprocating movement of the piston in the cylinder of the linear compressor, high-pressure gas can enter the air cavity through the first air passage under the control of the first air valve, and then enter the inner side surface of the pneumatic bushing through the air cavity. Since a plurality of throttle holes are provided on the side wall of the pneumatic bushing, when the high-pressure gas exits simultaneously from the plurality of throttle holes, an annular pneumatic diaphragm can be formed between the outer side surface of the pneumatic bushing and the opposite wall surface of the cylinder. This pneumatic diaphragm can not only provide a good supporting effect for the reciprocating movement of the piston in the cylinder, ensuring non-contact operation of the piston in the cylinder, but also preferably prevent the high-pressure gas in the compression cavity of the linear compressor from entering the back pressure cavity along the air gap between the piston and the cylinder; as the piston reciprocates in the cylinder and the pneumatic bushing works for a long time, when the air pressure in the back pressure cavity increases due to the gradual accumulation of the internal gas, the second air valve can also be opened, so that the gas in the back pressure cavity enters the air cavity through the second air passage and continues to be delivered to the pneumatic bushing. In this way, not only can the pneumatic action of the pneumatic bushing provide support for the reciprocating movement of the piston in the cylinder, but also the air pressures inside the compression cavity and the back pressure cavity can be balanced, preventing the imbalance of the air pressures between the compression cavity and the back pressure cavity caused by the long-term operation of the pneumatic bushing and avoiding affecting the compression operation of the linear compressor.

[0019] As can be seen, based on the improvement of the piston, the present invention overcomes the problem that the piston in the existing linear compressor can only provide moving support through the resonant plate springs arranged on both sides of the linear compressor, realizes the non-contact operation of the piston in the cylinder, greatly reduces the axial dimension of the linear compressor, reduces the clearance leakage of high-pressure gas generated between the cylinder and the piston, and effectively improves the efficiency of the linear compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 is a schematic cross-sectional structure diagram of a piston provided by the present invention;

[0022] Figure 2 is one of the schematic axial cross-sectional structure diagrams of the linear compressor provided by the present invention;

[0023] Figure 3 is another schematic axial cross-sectional structure diagram of the linear compressor provided by the present invention;

[0024] Figure 4 is the third schematic axial cross-sectional structure diagram of the linear compressor provided by the present invention;

[0025] Figure 5 is provided by the present invention Figure 4 axial structure diagram of the movement in it;

[0026] Figure 6 is provided by the present invention Figure 4 radial cross-sectional structure diagram of the movement in it;

[0027] Figure 7 is the fourth schematic axial cross-sectional structure diagram of the linear compressor provided by the present invention;

[0028] Figure 8 is one of the schematic structure diagrams of the leaf spring provided by the present invention;

[0029] Figure 9 is another schematic structure diagram of the leaf spring provided by the present invention;

[0030] Figure 10 is the third schematic structure diagram of the leaf spring provided by the present invention;

[0031] Reference numerals:

[0032] 1: Piston; 2: Stator; 3: Rotor;

[0033] 4: Leaf spring; 5: Cylinder; 6: Housing;

[0034] 7: Compression chamber; 8: Back pressure chamber; 9: Exhaust passage;

[0035] 10: Vibration damping structure; 11: Anti - collision device; 12: Ventilation passage;

[0036] 13: First fixing member; 14: Second fixing member; 101: Piston body;

[0037] 102: Air cavity; 103: First air passage; 104: Second air passage;

[0038] 105: First air valve; 106: Second air valve; 107: Pneumatic bushing;

[0039] 108: Vent hole; 1011: First section; 1012: Second section;

[0040] 1013: Connection seat; 21: Inner stator; 22: Outer stator;

[0041] 221: Iron core; 222: Excitation winding; 31: Rotor skeleton;

[0042] 32: Ring permanent magnet; 110: Vibration damping spring; 111: Vibration damping block;

[0043] 100: Movement. Detailed implementation manners

[0044] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0045] The following is combined with Figures 1 - 10 Describe a piston and a linear compressor of the present invention.

[0046] As Figure 1As shown in the figure, this embodiment provides a piston. The piston 1 includes: a piston body 101, a first air passage 103, a second air passage 104, a first air valve 105, a second air valve 106, and a pneumatic bushing 107. An air cavity 102 is formed inside the piston body 101. The first ends of the first air passage 103 and the second air passage 104 are both communicated with the air cavity 102. The second end of the first air passage 103 is formed at one end of the piston body 101, and the second end of the second air passage 104 is formed at the other end of the piston body 101. The first air valve 105 is installed in the first air passage 103, and the second air valve 106 is installed in the second air passage 104. The pneumatic bushing 107 is sleeved on the side wall of the piston body 101, and the air cavity 102 is communicated with the inner side surface of the pneumatic bushing 107. A plurality of throttle air holes are formed on the side wall of the pneumatic bushing 107. Among them, the first air valve 105 and the second air valve 106 shown in this embodiment can be understood as one-way valves or reed valves that can be automatically opened or closed according to the change of air pressure, and no specific limitation is made here.

[0047] Specifically, during the reciprocating movement of the piston 1 shown in this embodiment in the cylinder 5 of the linear compressor, the high-pressure gas can enter the air cavity 102 through the first air passage 103 under the control of the first air valve 105, and then enter the inner side surface of the pneumatic bushing 107 through the air cavity 102. Since a plurality of throttle air holes are provided on the side wall of the pneumatic bushing 107, when the high-pressure gas exits from the plurality of throttle air holes simultaneously, an annular pneumatic diaphragm can be formed between the outer side surface of the pneumatic bushing 107 and the opposite wall surface of the cylinder 5. This pneumatic diaphragm can not only provide a good supporting effect for the reciprocating movement of the piston 1 in the cylinder 5, ensuring that the piston 1 runs without contact in the cylinder 5, but also can better prevent the high-pressure gas in the compression cavity 7 of the linear compressor from entering the back pressure cavity 8 along the air gap between the piston 1 and the cylinder 5. As the piston 1 reciprocates in the cylinder 5 and the pneumatic bushing 107 works for a long time, when the air pressure in the back pressure cavity 8 increases due to the gradual accumulation of the internal gas, the second air valve 106 can also be opened, so that the gas in the back pressure cavity 8 enters the air cavity 102 through the second air passage 104 and continues to be conveyed to the pneumatic bushing 107. In this way, not only can the pneumatic action of the pneumatic bushing 107 provide support for the reciprocating movement of the piston 1 in the cylinder 5, but also the air pressures inside the compression cavity 7 and the back pressure cavity 8 can be balanced, preventing the imbalance of the air pressures between the compression cavity 7 and the back pressure cavity 8 caused by the long-term work of the pneumatic bushing 107 and avoiding affecting the compression operation of the linear compressor.

[0048] It can be seen that based on the improvement of the piston 1, the present invention overcomes the problem that the piston 1 in the existing linear compressor can only provide moving support through the resonance plate springs arranged on both sides of the linear compressor, realizes the non-contact operation of the piston 1 in the cylinder 5, greatly reduces the axial dimension of the linear compressor, reduces the gap leakage generated by the high-pressure gas between the cylinder 5 and the piston 1, and effectively improves the efficiency of the linear compressor.

[0049] As Figure 1 shown, the air chamber 102 shown in this embodiment extends along the axial direction of the piston body 101, and the air chamber 102 can be specifically set as a cylindrical shape. Vent holes 108 are formed on the wall surface of the air chamber 102, and a plurality of vent holes 108 can be provided. Each vent hole 108 extends along the radial direction of the piston body 101, and the vent hole 108 communicates with the inner side surface of the pneumatic bushing 107. Here, a plurality of vent holes 108 can be specifically arranged circumferentially in each area corresponding to the inner side surface of the pneumatic bushing 107, so as to ensure that the inner side surface of the pneumatic bushing 107 can uniformly receive the high-pressure gas from the air chamber 102.

[0050] At the same time, in this embodiment, the outer side surface of the pneumatic bushing 107 can also be set to be flush with or higher than the side surface of the piston body 101, so as to minimize the contact friction between the outer side surface of the pneumatic bushing 107 and the inner wall surface of the cylinder 5 on the linear compressor.

[0051] It should be noted here that the pneumatic bushing 107 shown in this embodiment is in a hollow cylindrical shape, the pneumatic bushing 107 is coaxially arranged with the piston body 101, the throttle air holes extend from the inner side surface to the outer side surface of the pneumatic bushing 107 along the radial direction of the pneumatic bushing 107, the aperture of the throttle air holes is specifically 0.001 - 1000 μm, and the throttle air holes are uniformly distributed in each area on the side wall of the pneumatic bushing 107. Among them, the pneumatic bushing 107 can be a porous foam metal component processed from metal powder or metal wire mesh, or a porous breathable ceramic component or porous breathable plastic component processed from non-metal powders such as carbon powder, graphite powder, alumina powder, silica powder, and engineering plastic powder, or a porous composite breathable component processed from a mixture of metal powder, metal wire mesh and non-metal powder.

[0052] In addition, in order to improve the working performance of the piston 1, a wear-resistant self-lubricating coating can be applied to the side surface of the piston body 101. The wear-resistant self-lubricating coating includes any one or a combination of at least two of a graphite-like coating (GLC), a polyetheretherketone coating (PEEK), a polyimide resin coating (PI), a diamond-like carbon coating (DLC), a Teflon coating (Teflon), 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), a titanium aluminum nitride coating (AlTiN), a titanium nitride coating (TiN), an alumina ceramic coating (Al2O3), and a phosphating coating (P).

[0053] As Figure 1 shown, the first air valve 105 and the second air valve 106 shown in this embodiment are both one-way valves. The first air valve 105 is used to control the airflow to enter the air chamber 102 from the first air passage 103 directionally, and the second air valve 106 is used to control the airflow to enter the air chamber 102 from the second air passage 104 directionally.

[0054] Specifically, the first air valve 105 and the second air valve 106 shown in this embodiment can be specifically arranged in the air chamber 102. The first air valve 105 is located at the first end of the first air passage 103, and the second air valve 106 is located at the first end of the second air passage 104. In this way, when the piston 1 moves toward the compression chamber 7 in the cylinder 5, as the air pressure in the compression chamber 7 increases, when the air pressure in the compression chamber 7 is higher than the air pressure inside the air chamber 102, under the action of the pressure difference, the high-pressure gas continuously flows into the air chamber 102 through the first air valve 105 until the air pressures in the air chamber 102 and the compression chamber 7 are balanced. This enables the gas in the air chamber 102 to maintain a relatively high pressure. When the gas in the air chamber 102 flows to the inner side surface of the pneumatic bushing 107 through the vent hole 108, a stable pneumatic diaphragm can be formed between the outer side surface of the pneumatic bushing 107 and the opposite wall surface of the cylinder 5, providing a good supporting effect for the reciprocating movement of the piston 1 in the cylinder 5 and effectively preventing the high-pressure gas in the compression chamber 7 of the linear compressor from entering the back pressure chamber 8 along the air gap between the piston 1 and the cylinder 5.

[0055] Since a part of the gas will enter the back pressure chamber 8 along the air gap between the piston 1 and the cylinder 5 during the process of the pneumatic diaphragm providing a supporting effect for the reciprocating movement of the piston 1, with the long-term operation of the pneumatic bushing 107, the air pressure in the back pressure chamber 8 increases due to the gradual accumulation of the internal gas. When the air pressure in the back pressure chamber 8 is greater than the air pressure inside the air chamber 102, under the action of the pressure difference, the second air valve 106 automatically opens, enabling the gas in the back pressure chamber 8 to enter the air chamber 102 through the second air passage 104, effectively balancing the air pressures in the compression chamber 7 and the back pressure chamber 8 and improving the compression ratio of the linear compressor.

[0056] As Figure 1 shown in Figure 2 FIG. 5, in order to facilitate the connection of the piston 1 with the leaf spring 4 and the mover 3 on the linear compressor, a connection seat 1013 is constructed at the other end of the piston body 101 shown in this embodiment.

[0057] Meanwhile, in order to facilitate the installation of the pneumatic bushing 107, the piston body 101 shown in this embodiment can be specifically set as a first section 1011 and a second section 1012; the first section 1011 and the second section 1012 are coaxially connected; the pneumatic bushing 107 is coaxially sleeved on the side wall of at least one of the first section 1011 and the second section 1012.

[0058] Specifically, in this embodiment, a first annular notch is formed on the side wall of the first section 1011, a second annular notch is formed on the side wall of the second section 1012, and when the first section 1011 and the second section 1012 are correspondingly butted, the first annular notch and the second annular notch are combined into an annular groove, and the pneumatic bushing 107 is embedded in the annular groove.

[0059] Meanwhile, the air chamber 102 and the second air passage 104 shown in this embodiment are constructed in the first section 1011, the first air passage 103 is constructed in the second section 1012, and the connection seat 1013 is constructed at the end of the first section 1011 away from the second section 1012.

[0060] Next, based on the piston 1 shown in the above embodiment, the structure of the linear compressor will be specifically described as follows.

[0061] Embodiment 1

[0062] As Figure 2 shown in FIG. 6, this embodiment provides a linear compressor, including a housing 6 and a core 100. The core 100 is placed in the cavity of the housing 6. The core 100 includes a stator 2, a mover 3, a leaf spring 4 and a cylinder 5. The stator 2, the mover 3 and the cylinder 5 are coaxially arranged. The stator 2 and the mover 3 form a linear motor. It also includes the piston 1 as described above. The piston 1 is slidably installed in the cylinder 5. A compression chamber 7 is formed between one end of the piston 1 and the wall surface of the first side of the housing 6, and a back pressure chamber 8 is formed between the other end of the piston 1 and the wall surface of the second side of the housing 6. An exhaust passage 9 is provided on the housing 6, and the exhaust passage 9 communicates with the compression chamber 7. The other end of the piston 1 and one end of the mover 3 are both connected to the middle of the leaf spring 4, and the end of the leaf spring 4 is connected to one end of the stator 2. Among them, the wall surfaces of the first side and the second side of the housing 6 are oppositely arranged on both sides of the cylinder 5.

[0063] Specifically, when the piston 1 moves towards the side facing the back pressure chamber 8, the linear compressor sucks air from the outside through the exhaust passage 9, and the outside gas enters the compression chamber 7 along the exhaust passage 9. During this process, the first air valve 105 is closed, and based on the air supply effect of the air chamber 102, a stable pneumatic diaphragm is formed between the outer side surface of the pneumatic bushing 107 and the opposite wall surface of the cylinder 5, providing a good supporting effect for the reciprocating movement of the piston 1 in the cylinder 5 and preferably preventing the gas from flowing between the compression chamber 7 and the back pressure chamber 8 along the air gap between the piston 1 and the cylinder 5.

[0064] Correspondingly, when the piston 1 moves towards the side facing the compression chamber 7, the gas inside the compression chamber 7 is compressed in a short time, resulting in a rapid increase in air pressure. When the air pressure in the compression chamber 7 is higher than the air pressure inside the air chamber 102, the first air valve 105 opens. Based on the air supply effect of the air chamber 102, a relatively stable pneumatic diaphragm is formed between the outer side surface of the pneumatic bushing 107 and the opposite wall surface of the cylinder 5, providing a good supporting effect for the reciprocating movement of the piston 1 in the cylinder 5 and preferably preventing the gas from flowing between the compression chamber 7 and the back pressure chamber 8 along the air gap between the piston 1 and the cylinder 5. Among them, during the process of the piston 1 compressing the gas, the high-pressure gas in the compression chamber 7 gradually discharges from the exhaust passage 9 again to realize the exhaust of the linear compressor.

[0065] Since while the pneumatic diaphragm provides a supporting effect for the reciprocating movement of the piston 1 in the cylinder 5, a part of the gas will enter the back pressure chamber 8 along the air gap between the piston 1 and the cylinder 5. With the long-term operation of the pneumatic bushing 107, the air pressure in the back pressure chamber 8 increases due to the gradual accumulation of the gas inside. When the air pressure in the back pressure chamber 8 is greater than the air pressure inside the air chamber 102, under the action of the pressure difference, the second air valve 106 automatically opens, enabling the gas in the back pressure chamber 8 to enter the air chamber 102 through the second air passage 104, effectively balancing the air pressures inside the compression chamber 7 and the back pressure chamber 8 and greatly increasing the compression ratio of the linear compressor.

[0066] As Figure 2 shown, two movement units 100 are provided inside the housing 6 shown in this embodiment. The two movement units 100 are arranged along the axial direction of the piston 1 and are arranged in an opposed manner. The compression chambers 7 on the two movement units 100 are both communicated with the exhaust passage 9. Here, by providing two opposed movement units 100 in this embodiment, when the linear compressor operates, the vibrations of the two movement units 100 can cancel each other out, effectively achieving the vibration reduction effect on the housing 6 of the linear compressor.

[0067] It should be noted here that multiple leaf springs 4 shown in this embodiment can be provided, and the multiple leaf springs 4 are sequentially connected in a stacked arrangement to form a resonant spring assembly. Among them, spring flat gaskets are provided between adjacent two layers of leaf springs 4.

[0068] The connection method between the resonant spring assembly shown in this embodiment and the piston 1 can be set in various forms. For example: the middle part of the resonant spring assembly is connected to the other end of the piston 1, and each end of the resonant spring assembly is connected to one end of the stator 2; or, at least one end of the resonant spring assembly is connected to the other end of the piston 1, and the other ends of the resonant spring assembly are connected to one end of the stator 2. Specific limitations are not made here.

[0069] At the same time, the leaf spring 4 shown in this embodiment includes elastic members distributed in the same plane or near the same plane, and the ends of the leaf spring 4 are free ends, and multiple free ends can be set. Here, the elastic member can be a first combined shape formed by sequentially connecting multiple straight segments and / or curved segments end to end, and free ends are respectively arranged at both ends of the first combined shape; that is, the elastic member has two free ends, and any number of straight segments and any number of curved segments can be connected in any bending form between the two free ends.

[0070] Or, the elastic member can be a second combined shape formed by connecting one ends of multiple straight segments and / or curved segments into one body, and the other ends of the corresponding straight segments or curved segments in the second combined shape are respectively set as free ends; that is, the elastic member has more than three free ends, and each free end is connected to the central part in any bending form by any straight segment or any curved segment.

[0071] In this embodiment, the resonant spring assembly shown can be sequentially connected in a stacked arrangement by using multiple leaf springs 4 having the first combined shape or the second combined shape shown in the above embodiment. Of course, the resonant spring assembly can also combine the leaf springs 4 of the first combined shape and the second combined shape. Here, based on the improved setting of the resonant spring assembly in this embodiment, only by setting the resonant spring assembly on one side of the linear compressor, it can drive the piston 1 to reciprocate in the cylinder 5 under the drive of the linear motor, and can greatly reduce the axial dimension of the linear compressor.

[0072] It should also be pointed out here that the first combined shape can be formed by bending a spring wire multiple times in the same plane. Obviously, the shape of each bending segment of the first combined shape includes straight segments, curved segments and their combinations, and the cross-section of the spring wire can be circular, elliptical, square or triangular, and specific limitations are not made here. Thus, the combined shape obtained by bending the leaf spring 4 can be "S" shape, "C" shape, "Z" shape, "L" shape, "ㄥ" shape, "V" shape, "U" shape, "∠" shape, "┓" shape, "く" shape, "へ" shape, "J" shape, etc.

[0073] Such as Figure 8As shown, the leaf spring 4 is specifically in the first combined shape, and is made of spring wire with a circular cross section and bent at least 6 times; its shape includes 5 straight lines, 4 connecting transition arcs (curve segments) and arc-shaped free ends at the head and tail ends for positioning and installation; thus, the corresponding free ends at the head and tail ends of the leaf spring 4 can be connected to the edge of the stator 2, and the center of the leaf spring 4 can be connected to the corresponding end of the piston 1 to support the piston 1 to achieve reciprocating motion in the cylinder 5. The specific form of the leaf spring 4 shown in this embodiment is as follows Figure 5 shown.

[0074] like Figure 9 As shown, the leaf spring 4 is specifically in the first combined shape, and is made of spring wire with a circular cross section and bent at least 12 times; its shape includes 10 circular arc segments (curved segments), 1 central connecting segment (straight segment) and arc-shaped free ends at the head and tail ends for positioning and installation. Of course, the first combined shape shown in this embodiment also includes other structural forms, which will not be listed here one by one.

[0075] At the same time, the leaf spring 4 can also be a second combination shape formed by connecting one end of multiple straight segments or curved segments into one body, and the other ends of the corresponding straight segments or curved segments in the second combination shape are respectively provided with free ends. Therefore, this type of leaf spring 4 is arranged radially and obviously includes multiple free ends.

[0076] like Figure 10 As shown, the leaf spring 4 is specifically in the second combined shape, and the three curved segments in the leaf spring 4 are arranged in a centrally symmetrical structure, wherein the cross section of each curved segment is rectangular, and one end of the three curved segments is connected by an annular structure, and the other end of the three curved segments is set as a corresponding free end, and the free end is a fan annular structure, and a plurality of fixing holes are opened on the fan annular structure. Thus, the annular structure at the center position of the leaf spring 4 can be connected to the corresponding end of the piston 1, and the fan annular structure corresponding to each radiating end of the leaf spring 4 can be connected to the corresponding stator 2, so as to support the piston 1 to realize reciprocating motion in the cylinder 5.

[0077] Furthermore, if Figure 2 As shown, an anti-collision device 11 is installed between the end of the cylinder 5 facing away from the leaf spring 4 and the housing 6 in this embodiment, and a ventilation channel 12 is constructed on the anti-collision device 11, and the compression chamber 7 and the exhaust channel 9 are connected through the ventilation channel 12.

[0078] It should be noted here that the anti-collision device 11 can specifically be a cylindrical member coaxially arranged with the cylinder 5. This member is further preferably a polytetrafluoroethylene engineering plastic part, and the ventilation channel 12 is distributed along the central axis of the polytetrafluoroethylene engineering plastic part. When the moving stroke of the piston 1 in the cylinder 5 is too large, the anti-collision device 11 can effectively buffer the piston 1 and prevent the piston 1 from directly impacting the outer shell 6.

[0079] Furthermore, the stator 2 shown in this embodiment includes an inner stator 21 and an outer stator 22. The inner stator 21 and the outer stator 22 are coaxially arranged. One of the inner stator 21 and the outer stator 22 is an iron core, and the other of the inner stator 21 and the outer stator 22 includes an iron core and an excitation winding; the rotor 3 includes a rotor skeleton 31 and an annular permanent magnet 32; the annular permanent magnet 32 is installed on the rotor skeleton 31; one end of the rotor skeleton 31 is respectively connected to the middle of the leaf spring 4 and the connecting seat 1013 on the piston body 101; the inner stator 21 is coaxially arranged inside the annular permanent magnet 32, and the outer stator 22 is coaxially arranged outside the annular permanent magnet 32; a cylindrical air gap is formed between the inner stator 21 and the outer stator 22, and the annular permanent magnet 32 is coaxially disposed inside the cylindrical air gap, or the one of the inner stator 21 and the outer stator 22 that is the iron core is connected to the annular permanent magnet 32.

[0080] As Figure 2 shown, when a cylindrical air gap is formed between the inner stator 21 and the outer stator 22, the cylindrical air gap is straight along the moving direction of the piston 1. The excitation windings 222 are circumferentially arranged on the iron core 221 of the outer stator 22, and the inner stator 21 is only provided as an iron core structure, and no excitation winding is provided on the inner stator 21. At the same time, the rotor 3 includes a set of annular permanent magnets 32, and the magnetic poles of the annular permanent magnets 32 are arranged radially along the linear compressor.

[0081] It should be noted here that the excitation windings 222 shown in this embodiment can also be circumferentially arranged on the iron core of the inner stator 21, and the outer stator 22 is only provided as an iron core structure, and no excitation winding is provided on the outer stator 22.

[0082] At the same time, the magnetic poles of the annular permanent magnets 32 shown in this embodiment are arranged radially along the linear compressor. It can be understood that the magnetic pole inside the annular permanent magnet 32 is the N pole and the magnetic pole outside is the S pole, or the magnetic pole inside the annular permanent magnet 32 is the S pole and the magnetic pole outside is the N pole. No specific limitation is made on this. Among them, the annular permanent magnet 32 can be an integral structure or can be formed by connecting a plurality of tile-shaped magnets arranged circumferentially through a shaping material.

[0083] In addition, it should also be noted that the linear motor shown in this embodiment further includes a first fixing member 13 and a second fixing member 14. When a cylindrical air gap is formed between the inner stator 21 and the outer stator 22, the outer stator 22 can be fixedly installed between the first fixing member 13 and the second fixing member 14. An extension portion axially extending toward one side of the first fixing member 13 is provided on the second fixing member 14, and the inner stator 21 is fixedly installed on the extension portion. Among them, both the first fixing member 13 and the second fixing member 14 are in the shape of a hollow cylinder, the cylinder 5 is coaxially installed inside the second fixing member 14, and the end of the leaf spring 4 is connected to a side surface of the first fixing member 13 away from the second fixing member 14 to realize the connection with one end of the stator 2.

[0084] Embodiment 2

[0085] As Figure 3 shown, based on the improvement of Embodiment 1, this embodiment further provides a linear compressor. The difference between Embodiment 2 and Embodiment 1 is that only one core 100 is provided inside the housing 6.

[0086] To ensure the stability of the linear compressor during operation, a damping structure 10 is installed in the back pressure chamber 8 in this embodiment. One end of the damping structure 10 is connected to the middle of the leaf spring 4, and the other end is connected to the housing 6. Among them, the damping structure 10 can be springs, shrapnel, elastic rods, etc. well known in the art, and no specific limitation is made here. Here, based on the buffering and damping effects of the damping structure 10, the vibration generated by the piston 1 during reciprocating motion in the cylinder 5 on the core 100 can be effectively offset, realizing the damping effect on the housing 6 of the linear compressor.

[0087] Specifically, the damping structure 10 shown in this embodiment includes a damping spring 110 and a damping block 111; the damping spring 110 is coaxially arranged with the piston 1; the damping block 111 is installed in the middle of the damping spring 110, one end of the damping spring 110 is connected to the middle of the leaf spring 4, and the other end is connected to the housing 6.

[0088] Thus, when the mover 3 and the piston 1 shown in this embodiment perform reciprocating motion, due to the resonance of the leaf spring 4 and the friction during the motion process, a slight vibration will be generated on the body of the linear compressor (other components except the mover 3). At this time, by setting the damping block 111 and the damping spring 110, a force opposite to the body of the linear compressor can be generated through the vibration of the damping block 111, thereby offsetting the vibration on the body of the linear compressor, and further achieving the damping effect on the body of the linear compressor.

[0089] Embodiment 3

[0090] As Figures 4 - 6As shown in the figure, this embodiment is an improvement based on Embodiment 1, and also provides a linear compressor. The difference between Embodiment 3 and Embodiment 1 is that when a cylindrical air gap is formed between the inner stator 21 and the outer stator 22, the cylindrical air gap is straight along the moving direction of the piston 1. The inner side surface of the corresponding iron core 221 of the outer stator 22 is provided with a plurality of protrusions arranged in a circumferential manner, and each protrusion is wound with an exciting winding 222. The mover 3 includes two sets of coaxially connected annular permanent magnets 32, and the magnetic poles of the two sets of annular permanent magnets 32 are arranged along the radial direction of the linear compressor and in opposite directions.

[0091] Specifically, eight protrusions can be specifically provided in this embodiment. Correspondingly, eight exciting coils arranged in a circumferential manner are wound on the outer stator 22, and the iron cores 221 of the inner stator 21 and the outer stator 22 are both stacked by a plurality of silicon steel sheets of corresponding shapes. At the same time, in this embodiment, the magnetic pole on the inner side of one of the sets of annular permanent magnets 32 on the mover 3 can be set as the N pole, and the magnetic pole on the outer side can be set as the S pole. Correspondingly, the magnetic pole on the inner side of the other set of annular permanent magnets 32 is set as the S pole, and the magnetic pole on the outer side is set as the N pole. In this way, when the magnetic field generated by the exciting winding 222 changes periodically, the mover 3 can be driven to reciprocate along the axial direction of the linear compressor based on the interaction of the magnetic fields between the exciting winding 222 and the two sets of annular permanent magnets 32. Each set of annular permanent magnets 32 can be an integral structure or can be composed of a plurality of tile-shaped magnets arranged in a circumferential manner and connected by a shaping material, which is not specifically limited here.

[0092] It should be noted here that in this embodiment, a plurality of protrusions arranged in a circumferential manner can also be provided on the outer side surface of the inner stator 21, and each protrusion is wound with an exciting winding 222, and the mover 3 is provided to include two sets of coaxially connected annular permanent magnets 32, and the magnetic poles of the two sets of annular permanent magnets 32 are arranged along the radial direction of the linear compressor and in opposite directions.

[0093] Embodiment 4

[0094] As Figure 7 As shown in the figure, this embodiment is an improvement based on Embodiment 3, and also provides a linear compressor. The difference between Embodiment 4 and Embodiment 3 is that in order to further ensure the stability of the linear compressor during operation, a damping structure 10 is provided in the back pressure chambers 8 corresponding to the two opposed movement mechanisms 100 in this embodiment. One end of the damping structure 10 is connected to the middle of the leaf spring 4, and the other end is connected to the housing 6.

[0095] Among them, the damping structure 10 shown in this embodiment includes a damping spring 110 and a damping block 111; the damping spring 110 is coaxially arranged with the piston 1; the damping block 111 is installed in the middle of the damping spring 110, one end of the damping spring 110 is connected to the middle of the leaf spring 4, and the other end is connected to the housing 6.

[0096] Meanwhile, this embodiment further improves the structure of the linear motor, which is specifically as follows:

[0097] When a cylindrical air gap is formed between the inner stator 21 and the outer stator 22, this embodiment specifically sets the connection between the inner stator 21 and the iron core 221 at one end of the outer stator 22 away from the leaf spring 4, so that one end of the cylindrical air gap away from the leaf spring 4 is closed; the exciting windings 222 are arranged circumferentially on the inner stator 21 or the outer stator 22, and the mover 3 includes two groups of coaxially connected annular permanent magnets 32. The magnetic poles of the two groups of annular permanent magnets 32 are arranged along the radial direction of the linear compressor and in opposite directions.

[0098] Here, this embodiment can specifically set the magnetic pole inside one group of annular permanent magnets 32 on the mover 3 to be the N pole and the magnetic pole outside to be the S pole. Correspondingly, the magnetic pole inside the other group of annular permanent magnets 32 is set to be the S pole and the magnetic pole outside to be the N pole. In this way, when the magnetic field generated by the exciting windings 222 changes periodically, based on the interaction of the magnetic fields between the exciting windings 222 and the two groups of annular permanent magnets 32, the mover 3 can be driven to reciprocate along the axial direction of the linear compressor relative to the stator 2.

[0099] Among them, by optimizing the configuration of the iron core 221 structures of the inner stator 21 and the outer stator 22 in this embodiment, there is only one air gap opening in the magnetic circuit of the linear motor, which can effectively reduce the air gap magnetic resistance of the stator magnetic circuit of the linear motor, improve the efficiency of the linear motor and the thrust on the mover 3, and further effectively improve the efficiency of the linear compressor.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A piston, characterized in that, Comprising: A piston body, in which an air chamber is formed; A first air passage and a second air passage, a first end of the first air passage and a first end of the second air passage are both communicated with the air chamber, a second end of the first air passage is formed at one end of the piston body, and a second end of the second air passage is formed at the other end of the piston body; A first air valve and a second air valve, the first air valve is installed in the first air passage, and the second air valve is installed in the second air passage; A pneumatic bushing, sleeved on the side wall of the piston body, the air chamber is communicated with the inner side surface of the pneumatic bushing, and a plurality of throttle air holes are formed on the side wall of the pneumatic bushing; The piston is configured to be slidably installed in a cylinder, a compression chamber is formed between one end of the piston and the wall surface of the first side of the housing, and a back pressure chamber is formed between the other end of the piston and the wall surface of the second side of the housing; The first air valve is used to open when the air pressure in the compression chamber is higher than the air pressure in the air chamber, so that the gas in the compression chamber enters the air chamber through the first air passage; the second air valve is used to open when the air pressure in the back pressure chamber is higher than the air pressure in the air chamber, so that the gas in the back pressure chamber enters the air chamber through the second air passage; Wherein, both the first air valve and the second air valve can be automatically opened or closed according to the change of air pressure.

2. The piston according to claim 1, wherein, Vent holes are formed on the wall surface of the air chamber, the vent holes are communicated with the inner side surface of the pneumatic bushing, and the outer side surface of the pneumatic bushing is flush with or higher than the side surface of the piston body.

3. The piston according to claim 1, characterized in that, Both the first air valve and the second air valve are one-way valves, the first air valve is used to control the air flow to be directed into the air chamber from the first air passage, and the second air valve is used to control the air flow to be directed into the air chamber from the second air passage.

4. The piston according to any one of claims 1 to 3, characterized in that, A connection seat is formed at the other end of the piston body; And / or, the piston body includes a first section and a second section; the first section and the second section are coaxially connected; the pneumatic bushing is coaxially sleeved on the side wall of at least one of the first section and the second section.

5. A linear compressor, comprising a housing and a core, wherein the core is disposed in a cavity of the housing, the core includes a stator, a mover, a leaf spring and a cylinder, the stator, the mover and the cylinder are coaxially arranged, and the stator and the mover form a linear motor, characterized in that, It further includes the piston according to any one of claims 1 to 4; The piston is slidably installed in the cylinder, a compression chamber is formed between one end of the piston and the wall surface of the first side of the housing, a back pressure chamber is formed between the other end of the piston and the wall surface of the second side of the housing, and an exhaust passage is provided on the housing, and the exhaust passage is communicated with the compression chamber; The other end of the piston and one end of the mover are both connected to the middle of the leaf spring, and the end of the leaf spring is connected to one end of the stator.

6. The linear compressor according to claim 5, characterized in that, A damping structure is installed in the back pressure chamber, one end of the damping structure is connected to the middle of the leaf spring, and the other end is connected to the housing.

7. The linear compressor according to claim 6, wherein The damping structure includes a damping spring and a damping block; the damping spring is coaxially arranged with the piston; the damping block is installed in the middle of the damping spring, one end of the damping spring is connected to the middle of the leaf spring, and the other end is connected to the housing.

8. The linear compressor according to any one of claims 5 to 7, characterized in that, One movement mechanism is arranged inside the housing; alternatively, two movement mechanisms are arranged inside the housing, the two movement mechanisms are arranged along the axial direction of the piston and are arranged in an opposed manner, and the compression chambers on the two movement mechanisms are both communicated with the exhaust passage; An anti-collision device is installed between one end of the cylinder away from the leaf spring and the housing, a ventilation passage is configured on the anti-collision device, and the compression chamber is communicated with the exhaust passage through the ventilation passage.

9. The linear compressor according to any one of claims 5 to 7, characterized in that, The stator includes an inner stator and an outer stator, the inner stator and the outer stator are coaxially arranged, one of the inner stator and the outer stator is an iron core, and the other of the inner stator and the outer stator includes an iron core and an exciting winding; The mover includes a mover skeleton and a ring permanent magnet; the ring permanent magnet is installed on the mover skeleton; one end of the mover skeleton is respectively connected to the middle of the leaf spring and the connecting seat on the piston body; The inner stator is coaxially arranged inside the ring permanent magnet, and the outer stator is coaxially arranged outside the ring permanent magnet; a cylindrical air gap is formed between the inner stator and the outer stator, the ring permanent magnet is coaxially arranged inside the cylindrical air gap, or the iron core of one of the inner stator and the outer stator is connected to the ring permanent magnet.

10. The linear compressor according to claim 9, wherein When a cylindrical air gap is formed between the inner stator and the outer stator, the cylindrical air gap is straight along the moving direction of the piston; the exciting winding is arranged circumferentially on the inner stator or the outer stator, the mover includes a group of ring permanent magnets, and the magnetic poles of the ring permanent magnets are arranged along the radial direction of the linear compressor; or, a plurality of protrusions arranged in a circumferential manner are provided on the outer side surface of the inner stator or the inner side surface of the outer stator, and the exciting winding is wound around each protrusion, the mover includes two groups of coaxially connected ring permanent magnets, and the magnetic poles of the two groups of ring permanent magnets are both arranged along the radial direction of the linear compressor and the arrangement directions are opposite; Or, when a cylindrical air gap is formed between the inner stator and the outer stator, the iron cores at one ends of the inner stator and the outer stator away from the leaf spring are connected so that one end of the cylindrical air gap away from the leaf spring is closed; the exciting winding is arranged circumferentially on the inner stator or the outer stator, the mover includes two groups of coaxially connected ring permanent magnets, and the magnetic poles of the two groups of ring permanent magnets are both arranged along the radial direction of the linear compressor and the arrangement directions are opposite.

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