Permanent magnetic piston for linear compressor and linear compressor

Abstract

The present application relates to the technical field of linear compressors, and discloses a permanent magnet piston for a linear compressor, including a piston body, a cavity, a first tube cavity and a plurality of second tube cavities are arranged inside the piston body, a first air port is arranged at one end of the piston body, a cavity is arranged at the other end inside the piston body, and a plurality of second air ports are evenly arranged on the side of the piston body, the first tube cavity connects the first air port and the cavity, and a plurality of second tube cavities connect the second air port and the first tube cavity; wherein, under the action of the internal and external air pressure difference, the gas in the compression chamber of the linear compressor can enter the permanent magnet piston through the first air port, and be discharged from the plurality of second air ports, so that the piston body is suspended. The permanent magnet piston disclosed in the present application reduces the starting stage, that is, the time for the piston to go from a stationary stage to a suspended stage, greatly reduces the friction during the operation of the piston, thereby increasing the operation efficiency of the linear compressor. The present application also discloses a linear compressor.

Description

Technical Field

[0001] The present application relates to the technical field of linear compressors, for example, to a permanent magnet piston for a linear compressor and a linear compressor. Background Art

[0002] Compared with traditional motors, linear compressors do not require intermediate conversion transmission devices and can directly convert electrical energy into mechanical energy of linear motion. They have the advantages of simple structure, high transmission efficiency, easy adjustment and control, and are an important driving component of Stirling refrigerators.

[0003] During the operation of a linear compressor, the piston usually runs at a frequency of 1-60Hz or even higher. During its reciprocating motion, friction and leakage are the main sources of loss. In existing designs, the radial motion of the piston is restricted by gap sealing and leaf spring fixation. However, due to wear and tear over time, it is difficult to maintain radial consistency. A small amount of tilt can cause a lot of wear. The life of the leaf spring also limits the life of the linear compressor. Poor design can cause the leaf spring to break easily, causing failures.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present application, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical components or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0006] The embodiments of the present disclosure provide a permanent magnet piston for a linear compressor and a linear compressor, so as to reduce friction during the operation of the piston and reduce the frequency of compressor failure.

[0007] In some embodiments, the permanent magnet piston for a linear compressor includes a piston body, a cavity, a first tube cavity and a plurality of second tube cavities are arranged inside the piston body, a first air port is arranged at one end of the piston body, the cavity is arranged at the other end inside the piston body, and a plurality of second air ports are evenly arranged on the side of the piston body, the first tube cavity connects the first air port and the cavity, and the plurality of second tube cavities connect the second air port and the first tube cavity; wherein, under the action of the internal and external air pressure difference, the gas in the compression chamber of the linear compressor can enter the permanent magnet piston through the first air port and be discharged from the plurality of second air ports to make the piston body suspended.

[0008] In some embodiments, the cavity and the first tube cavity constitute a first Helmholtz resonance structure, and the cavity and the second tube cavity constitute a second Helmholtz resonance structure; the alternating oscillating compression chamber gas enters from the first air port, and the compression chamber gas forms a sound resonance inside the piston body, thereby enhancing the vibration energy, and the enhanced energy flows out from the second air port to support the permanent magnet piston to be suspended in the compression chamber of the compressor.

[0009] In some embodiments, the first resonant frequency of the Helmholtz resonant structure, the second resonant frequency of the second Helmholtz resonant structure are the same as the operating frequency of the compressor.

[0010] In some embodiments, the acoustic sensation and acoustic capacity of the first Helmholtz resonance structure and the second Helmholtz resonance structure satisfy Among them, ω is the angular frequency, l is the sound sensation, and c is the sound capacity.

[0011] In some embodiments, the piston body is axially composed of an air inlet section, an air outlet section and a cavity section; the first air port is located in the air inlet section, the plurality of second air ports are located in the air outlet section, and the cavity is located in the cavity section; the first tube cavity connects the air inlet section, the air outlet section and the cavity section.

[0012] In some embodiments, the first air port is located in the middle of the first end surface of the piston body; a plurality of second air ports are evenly arranged along the circumference of the piston body; the cavity is located in the middle of the second end of the piston body; the first tubular cavity extends axially along the piston body and is located in the middle of the piston body; and a plurality of second tubular cavities are arranged perpendicular to the first tubular cavity.

[0013] In some embodiments, the surface of the piston body has a wear-resistant coating.

[0014] In some embodiments, the linear compressor includes an annular silicon steel sheet and a permanent magnet piston as described above for a linear compressor: the annular silicon steel sheet is used to convert into an electromagnet with a changing magnetic field direction when an alternating current is passed through it; the permanent magnet piston is installed in the middle hollow core of the annular silicon steel sheet and performs reciprocating motion under the action of the Ampere force.

[0015] In some embodiments, there is a gap of 0.08-0.12 μm between the annular silicon steel sheet and the permanent magnet piston.

[0016] In some embodiments, the linear compressor further includes a yoke, which is disposed on the outside of the annular silicon steel sheet and is used to limit the range of the magnetic field to enhance the magnetic field strength in the middle of the annular silicon steel sheet.

[0017] The permanent magnet piston for a linear compressor and the linear compressor provided by the embodiments of the present disclosure can achieve the following technical effects:

[0018] Compared with the prior art, the permanent magnet piston disclosed in the present invention eliminates the gap sealing and leaf spring fixing settings, and a cavity, a first tube cavity, and a plurality of second tube cavities are set in the piston body. Due to the existence of the cavity, under the action of the internal and external air pressure difference, the compression chamber gas can enter the permanent magnet piston through the first air port and be discharged from the second air port.

[0019] The second air port is arranged in a ring shape on the side of the piston body, so that the air outlet position of the permanent magnet piston is relatively uniform, which can make the piston body suspended, reduce the friction generated by the permanent magnet piston during the reciprocating motion, and eliminate the limitation of the leaf spring life on the life of the linear compressor, thereby reducing the occurrence of compressor failure due to leaf spring breakage.

[0020] Compared with traditional gas piston bearings, the permanent magnet piston disclosed in the present invention generates a stronger gas suspension force and can support the piston more stably, especially reducing the starting phase, that is, the time it takes for the piston to go from a stationary state to a suspended phase, thereby greatly reducing the friction during the operation of the piston and increasing the operating efficiency of the linear compressor.

[0021] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily described by corresponding drawings, which do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements, and the drawings do not constitute a scale limitation, and wherein:

[0023] Figure 1 is a structural schematic diagram of a permanent magnet piston provided by an embodiment of the present disclosure;

[0024] Figure 2 is a schematic structural diagram of another permanent magnet piston provided in an embodiment of the present disclosure;

[0025] Figure 3 is a schematic structural diagram of another permanent magnet piston provided in an embodiment of the present disclosure;

[0026] Figure 4 It is a structural schematic diagram of a linear compressor provided in an embodiment of the present disclosure.

[0027] Reference numerals:

[0028] 10: piston body; 11: first air port; 12: second air port; 13: first lumen; 14: second lumen; 15: cavity;

[0029] 20: Annular silicon steel sheet;

[0030] 30: yoke;

[0031] 40: housing; 41: compression chamber; 42: back pressure chamber. DETAILED DESCRIPTION

[0032] In order to be able to understand the features and technical contents of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0033] The terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so as to describe the embodiments of the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0034] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0035] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0036] Unless otherwise stated, the term "plurality" means two or more.

[0037] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B indicates: A or B.

[0038] The term "and / or" is a description of the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0040] Combination Figure 1-4 As shown, an embodiment of the present disclosure provides a permanent magnet piston for a linear compressor including a piston body 10 .

[0041] The piston body 10 is provided with a cavity 15, a first tube cavity 13 and a plurality of second tube cavities 14. A first gas port 11 is provided at one end of the piston body 10, a plurality of second gas ports 12 are evenly provided on the side of the piston body 10, and a cavity 15 is provided at the other end of the piston body 10; the first tube cavity 13 connects the first gas port 11 with the cavity 15, and the second tube cavity 14 connects the second gas port 12 with the first tube cavity 13. Under the action of the internal and external pressure difference, the gas in the compression chamber of the linear compressor can enter the permanent magnet piston through the first gas port 11 and be discharged from the plurality of second gas ports 12, so that the piston body 10 is suspended.

[0042] The permanent magnet piston provided by the embodiment of the present disclosure eliminates the gap sealing and leaf spring fixing settings compared to the prior art, and a cavity 15, a first tube cavity, and a plurality of second tube cavities 14 are set in the piston body 10. Due to the existence of the cavity 15, under the action of the internal and external air pressure difference, the gas in the compression chamber 41 can enter the permanent magnet piston through the first air port 11 and be discharged from the plurality of second air ports 12, so that the piston body is suspended.

[0043] The second air port 12 is evenly arranged in a ring shape on the side of the piston body 10, so that the air outlet position of the permanent magnet piston is relatively uniform, which can make the piston body 10 suspended, reduce the friction generated by the permanent magnet piston during the reciprocating motion, and eliminate the limitation of the leaf spring life on the life of the linear compressor, thereby reducing the occurrence of compressor failure due to leaf spring breakage.

[0044] Compared with traditional gas piston bearings, the permanent magnet piston disclosed in the present invention generates a stronger gas suspension force and can support the piston more stably, especially reducing the starting phase, that is, the time it takes for the piston to go from a stationary state to a suspended phase, thereby greatly reducing the friction during the operation of the piston and increasing the operating efficiency of the linear compressor.

[0045] As an example, after the gas in the compression chamber 41 enters the permanent magnet piston through the first gas port 11, part of it is discharged from the second gas port 12, and part of it is discharged from the second gas port 12 through the second tube cavity 14 after passing through the first tube cavity 13 and the cavity 15. Both can provide supporting force for the permanent magnet piston.

[0046] As another example, the aperture of the second air port 12 is smaller than or equal to the aperture of the first air port 11, so as to increase the resistance of the intake air flowing out of the second air port 12, so that the intake air resonates through the first tube cavity 13 and the cavity 15 to increase the resonance frequency and then flows out from the second air port 12, so that the air intake and exhaust process in the piston body 10 proceeds in an orderly manner.

[0047] Optionally, the cavity 15 and the first tube cavity 13 constitute a first Helmholtz resonance structure, and the cavity 15 and the second tube cavity 14 constitute a second Helmholtz resonance structure; the alternating oscillating compression chamber 41 gas enters from the first air port 11, and the compression chamber 41 gas forms a sound resonance inside the piston body 10, thereby enhancing the vibration energy, and the enhanced energy flows out from the second air port 12 to support the permanent magnet piston to be suspended in the compression chamber 41 of the compressor.

[0048] It is understandable that the current sound energy collectors all use Helmholtz resonant cavity or phononic crystal as the basic components for gathering sound energy. Phononic crystals are used in the field of sound energy collection because they can gather sound energy at their defects, but they are generally used in the field of high-frequency sound energy collection, because the wavelength of low-frequency sound energy is very long, and the corresponding requirement is that the phononic crystal must have a sufficiently large volume, which brings inconvenience to the actual operation; the Helmholtz resonant cavity is composed of a cavity 15 and a short tube. When resonating, the gas in the cavity is periodically compressed and expanded by the gas at the short tube, generating a large-amplitude resonant sound wave in the cavity. The ability of the Helmholtz resonant cavity to amplify the sound pressure depends on the volume ratio of the cavity 15 to the short tube, and is not affected by the shape and volume of the resonant cavity. By designing appropriate structural parameters, the sound energy collector using the Helmholtz resonant cavity can collect sound energy of various frequency bands with a small volume, which is convenient for micro-processing and integration into the circuit, and is therefore widely used in the field of sound energy collection.

[0049] The present disclosure sets the piston body 10 as a Helmholtz resonance structure, which can collect and amplify the pressure fluctuations entering the piston body 10. For the permanent magnet piston, a first air port 11 is opened at the front end of the piston for the gas of the alternating oscillating compression chamber 41 to enter. The interior of the piston is a Helmholtz resonance structure composed of an elongated first tube cavity 13 and a cavity 15. The alternating oscillating gas forms a sound resonance in the Helmholtz resonance structure, which enhances the vibration energy. The enhanced energy flows out from the second air port 12 on the side, thereby supporting the piston.

[0050] Optionally, the first resonance frequency of the first Helmholtz resonance structure and the second resonance frequency of the second Helmholtz resonance structure are the same as the operating frequency of the compressor.

[0051] It is understandable that in order to ensure that the gas has sufficient force to support the piston to float during movement, the frequency of the resonant structure must be consistent with the operating frequency of the piston body and the operating frequency of the compressor, thereby ensuring that the acoustic vibration frequency determined by the sound sensation and sound capacity meets the resonance requirements.

[0052] As an example, the sound resonance frequency of the first Helmholtz resonance structure formed by the first tube cavity 13 and the cavity 15 is 60Hz, which is consistent with the compressor operating frequency of 60Hz. At the same time, the resonance frequency of the second Helmholtz resonance structure formed by the cavity 15 and the side exhaust port is also 60Hz, which is consistent with the operating frequency. This can ensure that the sound of the suction is effectively amplified, and the vibration kinetic energy is more concentrated and intense, so that the discharged gas is more powerful, which can more effectively support and suspend the piston.

[0053] Optionally, the acoustic sensation and acoustic capacity of the Helmholtz resonance structure satisfy Among them, ω is the angular frequency, l is the sound sensation, and c is the sound capacity.

[0054] It can be understood that in order to ensure the resonance of the Helmholtz resonance structure, so as to achieve the function of collecting and amplifying the incoming pressure fluctuations, the sound sense and sound volume of each Helmholtz resonance structure meet the requirements. In order to ensure that the gas has enough force to support the piston to suspend during movement, the frequency of the resonant structure, that is, the frequency determined by the formula, must be consistent with the operating frequency of the piston. This requires the use of the above series of equations to calculate the volume and structural dimensions of the small holes and cavities, so as to ensure that the acoustic vibration frequency determined by the acoustic sense and acoustic capacity meets the resonance requirements.

[0055] For the Helmholtz resonance structure, its slender first cavity and the cavity work together and follow the acoustic impedance equation. Specifically, the momentum equation and continuity equation that control it are as follows:

[0056]

[0057]

[0058] In this case, it is assumed that both the pressure wave and the volume flow are sinusoidally distributed.

[0059] For its acoustic resistance

[0060]

[0061] For its sound

[0062]

[0063] For its thermal relaxation acoustic conductance

[0064]

[0065] For its voice

[0066]

[0067] The coefficient f in the calculation formula for the four acoustic impedances is v and f k yes

[0068]

[0069]

[0070] The specific symbol marking contents are shown in the following table.

[0071] symbol parameter unit A area <![CDATA[m 2 ]]> c Voice <![CDATA[m 2 / Well]]> <![CDATA[f k ]]> Thermal viscosity - <![CDATA[f v ]]> Thermal viscosity - <![CDATA[g k ]]> Thermal relaxation resistance <![CDATA[m 2 / Step]]> i Imaginary Unit - Im[] Impedance imaginary part - <![CDATA[J 0 []]]> Bessel function - <![CDATA[J 1 []]]> Bessel function - l Sound <![CDATA[kg / m 5 ]]> n Number of tubes - p pressure Pa <![CDATA[p m ]]> Average pressure Pa <![CDATA[r μ ]]> Acoustic resistance <![CDATA[Pa·s / m 4 ]]> R Twice the hydraulic diameter m Re[] Real impedance - U Volume flow <![CDATA[m 3 / s]]> x Axial position m γ Specific heat ratio - <![CDATA[δ v ]]> Viscous penetration depth m ρ density <![CDATA[kg / m 3 ]]> ω Angular frequency rad / s

[0072] Optionally, the piston body 10 is axially composed of an air inlet section, an air outlet section and a cavity 15 section; the first air port 11 is located in the air inlet section, the plurality of second air ports 12 are located in the air outlet section, and the cavity 15 is located in the cavity 15 section; the first tube cavity 13 connects the air inlet section, the air outlet section and the cavity 15 section.

[0073] It can be understood that the air outlet section of the present disclosure is located between the air inlet section and the cavity 15 section, and the first tube cavity 13 participates in both the air inlet and the air outlet process. The gas entering from the first air port 11 is transmitted to the cavity 15 section through the first tube cavity 13. After the oscillating gas is enhanced by the first tube cavity 13 and the cavity 15, it flows back through the first tube cavity 13 and is discharged from the piston body 10 through the plurality of second tube cavities 14 and the second air port 12. This structural design has the following advantages:

[0074] Firstly, it can avoid damaging the structure of the cavity 15 and affecting the resonance effect of the Helmholtz resonance structure; secondly, although the first tube cavity 13 participates in both the air intake and air exhaust processes, the energy enhanced by the Helmholtz resonance structure can be discharged from the second air port 12 through the second tube cavity 14, thereby reducing the interference between the air intake and the air exhaust; thirdly, the air outlet section is located in the middle of the piston body 10, so that the force center of the supporting force obtained by the piston body 10 can be close to the center of gravity of the piston body 10, so that the position of the piston body 10 in the height direction is relatively stable, thereby reducing the generation of friction; fourthly, this method can be easy to process.

[0075] Optionally, the first air port 11 is located in the middle of the first end surface of the piston body 10; a plurality of second air ports 12 are evenly arranged along the circumference of the piston body 10; the cavity 15 is located in the middle of the second end of the piston body 10; the first tubular cavity 13 extends along the axial direction of the piston body 10 and is located in the middle of the piston body 10; and a plurality of second tubular cavities 14 are arranged perpendicular to the first tubular cavity 13.

[0076] It can be understood that the first gas port 11 and the first tube cavity 13 are located on the axis of the piston body 10 , the axis of the cavity 15 is colinear with the axis of the first gas port 11 , and the plurality of second tube cavities 14 are evenly arranged around the first tube cavity 13 .

[0077] As an example, six second air ports 12 are circumferentially arranged in the front middle of the piston body 10 , and are arranged in two rows, with a total of 12. Each second air port 12 is connected to the interior of the piston through the second tube cavity 14.

[0078] Optionally, the surface of the piston body 10 has a wear-resistant coating, which can reduce the wear of the piston body 10.

[0079] Combination Figure 1-4 As shown, an embodiment of the present disclosure provides a linear compressor, including an annular silicon steel sheet 20 and a permanent magnet piston for a linear compressor as described above.

[0080] The annular silicon steel sheet 20 is used to transform into an electromagnet with a changing magnetic field direction when an alternating current is passed through it.

[0081] The permanent magnet piston is installed in the middle hollow core of the annular silicon steel sheet 20 and performs reciprocating motion under the action of the Ampere force.

[0082] It can be understood that the permanent magnet piston is installed in the middle hollow core of the annular silicon steel sheet 20. When the annular silicon steel sheet 20 is energized, the Ampere force generated can enable the permanent magnet piston to move in the middle hollow core. Since the annular silicon steel sheet 20 is passed with an alternating current, when the direction of the magnetic field changes, the movement direction of the permanent magnet piston will also change, which will cause the permanent magnet piston to reciprocate under the action of the Ampere force.

[0083] With the linear compressor provided by the embodiment of the present disclosure, under the action of the internal and external air pressure difference, the gas in the compression chamber 41 can enter the interior of the permanent magnet piston through the first air port 11 and be discharged from its second air port 12. Compared with the traditional gas piston bearing, the gas suspension force generated by the permanent magnet piston of the present disclosure is stronger, which can support the piston more stably, especially reducing the starting stage, that is, the time for the piston to go from static to suspended stage, greatly reducing the friction during the operation of the piston, thereby increasing the operating efficiency of the linear compressor. And the limitation of the life of the leaf spring on the life of the linear compressor is removed, reducing the occurrence of compressor failures due to leaf spring breakage.

[0084] As an example, the annular silicon steel sheet 20 may be a thin sheet stacking structure or an integral structure.

[0085] As another example, the annular silicon steel sheets 20 are symmetrically arranged inside the annular silicon steel sheets, and when an alternating current is passed through the annular silicon steel sheets, the annular silicon steel sheets 20 can be transformed into an electromagnet with a changing direction.

[0086] Optionally, there is a gap of 0.08-0.12 μm between the annular silicon steel sheet 20 and the permanent magnet piston.

[0087] It is understandable that there is a very small gap between the permanent magnet and the silicon steel sheet, and the gap should be as small as possible without friction, which is 0.08-0.12 μm, preferably 0.1 μm. This can reduce the gas leakage between the compression chamber 41 and the back pressure chamber 42 of the compressor and improve the efficiency of the compressor.

[0088] Optionally, the linear compressor further includes a yoke 30 , which is disposed outside the annular silicon steel sheet 20 and is used to limit the range of the magnetic field so as to enhance the magnetic field strength in the middle of the annular silicon steel sheet 20 .

[0089] It can be understood that the yoke 30 is arranged around the annular silicon steel sheet 20, which can play the role of binding the magnetic flux lines, and can limit the magnetic field generated by the silicon steel sheet to a certain range, making the magnetic field more uniform and powerful.

[0090] As an example, the working fluid of a Stirling refrigerator is helium or hydrogen.

[0091] Combination Figures 1 to 4 As shown, the linear compressor of the present disclosure is described below.

[0092] A linear compressor comprises a housing 40, an annular silicon steel sheet 20, a magnetic yoke 30 and a permanent magnet piston.

[0093] The linear compressor housing 40 plays a role of protection and sealing; the annular silicon steel sheet 20 is symmetrically arranged inside it, and when an alternating current is passed through it, it can be converted into an electromagnet with a changing direction; the yoke 30 is arranged around the annular silicon steel sheet 20, and plays a role of binding the magnetic flux lines, which can limit the magnetic field generated by the silicon steel sheet to a certain range, making the magnetic field more uniform and powerful; the permanent magnet piston is placed in the middle hollow core of the annular silicon steel sheet 20, and can perform reciprocating motion due to the Ampere force of the energized annular silicon steel sheet 20.

[0094] There is a very small gap of about 0.1 μm between the permanent magnet piston and the annular silicon steel sheet 20 .

[0095] For the permanent magnet piston, a first air port 11 is opened at the front end of the piston body 10 for the gas of the alternating oscillating compression chamber 41 to enter. The interior of the piston is a first Helmholtz resonance structure composed of a slender first tube cavity 13 and a cavity 15. The alternating oscillating gas forms a sound resonance in the Helmholtz resonance structure, and the vibration energy is enhanced. The enhanced energy flows out from the second air port 12 on the side, thereby supporting the piston.

[0096] In order to ensure that the gas has enough force to support the piston to float during movement, the frequency of the resonant structure must be consistent with the operating frequency of the piston, thereby ensuring that the acoustic vibration frequency determined by the sound sense and sound volume meets the resonance requirements.

[0097] Preferably, the sound resonance frequency of the first Helmholtz resonance structure formed by the first tube cavity 13 and the cavity 15 is 60Hz, which is consistent with the compressor operating frequency of 60Hz. At the same time, the resonance frequency of the second Helmholtz resonance structure formed by the cavity 15 and the second tube cavity 14 is also 60Hz, which is consistent with the operating frequency. In this way, it can be ensured that the sound of the suction is effectively amplified, and the vibration kinetic energy is more concentrated and intense, so that the discharged gas is more powerful, which can more effectively support and suspend the piston.

[0098] Preferably, the working fluid of the Stirling refrigerator is helium or hydrogen.

[0099] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural and other changes. The embodiments represent only possible variations. Unless explicitly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. The embodiments of the present disclosure are not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A permanent magnet piston for a linear compressor, characterized in that: include: A piston body (10) is provided with a first air port (11) at one end, and a plurality of second air ports (12) are evenly provided on the side of the piston body (10); A cavity (15) is arranged at the other end of the piston body (10); a first tube cavity (13), which is disposed inside the piston body (10) and communicates with the first gas port (11) and the cavity (15); and A plurality of second cavities (14) are disposed inside the piston body (10) and connect the second air port (12) and the first cavities (13). Wherein, under the action of the internal and external air pressure difference, the gas in the compression chamber of the linear compressor can enter the interior of the permanent magnetic piston through the first air port (11) and be discharged from the plurality of second air ports (12), so that the piston body (10) is suspended; The cavity (15) and the first tube cavity (13) constitute a first Helmholtz resonance structure, and the cavity (15) and the second tube cavity (14) constitute a second Helmholtz resonance structure; The alternatingly oscillating compression chamber (41) gas enters from the first gas port (11), and the compression chamber (41) gas forms a sound resonance inside the piston body (10), thereby enhancing the vibration energy. The enhanced energy flows out from the second gas port (12) to support the permanent magnet piston to be suspended in the compression chamber (41) of the compressor.

2. The permanent magnet piston according to claim 1, characterized in that: A first resonance frequency of the first Helmholtz resonance structure and a second resonance frequency of the second Helmholtz resonance structure are the same as an operating frequency of the compressor.

3. The permanent magnet piston according to claim 2, characterized in that: The acoustic sense and acoustic capacity of the first Helmholtz resonance structure and the second Helmholtz resonance structure both satisfy Among them, ω is the angular frequency, l is the sound sensation, and c is the sound capacity.

4. The permanent magnet piston according to any one of claims 1 to 3, characterized in that: The piston body (10) is composed of an air inlet section, an air outlet section and a cavity (15) section in sequence along the axial direction; The first air port (11) is located in the air inlet section, the plurality of second air ports (12) are located in the air outlet section, and the cavity (15) is located in the cavity (15) section; The first tube cavity (13) is connected to the air inlet section, the air outlet section and the cavity (15) section.

5. The permanent magnet piston according to claim 4, characterized in that: The first gas port (11) is located in the middle of the first end surface of the piston body (10); The plurality of second gas ports (12) are evenly arranged along the circumference of the piston body (10); The cavity (15) is located in the middle of the second end of the piston body (10); The first tube cavity (13) extends along the axial direction of the piston body (10) and is located in the middle of the piston body (10); The plurality of second tube cavities (14) are arranged perpendicularly to the first tube cavity (13).

6. The permanent magnet piston according to claim 5, characterized in that: The surface of the piston body (10) is provided with a wear-resistant coating.

7. A linear compressor, characterized in that: include: The annular silicon steel sheet (20) is used to convert into an electromagnet with a changing magnetic field direction when an alternating current is passed through it; The permanent magnet piston for a linear compressor as claimed in any one of claims 1 to 6 is installed in the middle hollow core of the annular silicon steel sheet (20) and performs reciprocating motion under the action of the Ampere force.

8. The linear compressor according to claim 7, characterized in that: There is a gap of 0.08 to 0.12 μm between the annular silicon steel sheet (20) and the permanent magnet piston.

9. The linear compressor according to claim 7, characterized in that: Also includes: A magnetic yoke (30) is arranged outside the annular silicon steel sheet (20) and is used to limit the range of the magnetic field so as to enhance the magnetic field strength in the middle of the annular silicon steel sheet (20).

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