Linear motor of linear compressor and linear compressor

Abstract

The invention relates to the technical field of compressors, in particular to a linear motor of a linear compressor and the linear compressor, a rotor assembly comprises main magnetic steel, and the main magnetic steel reciprocates under the action of a magnetic field excited after a stator assembly is electrified; the electromagnetic spring comprises a first electromagnetic spring and a second electromagnetic spring which are arranged on the two axial sides of the main magnetic steel, and the direction of the spring resultant force of the first electromagnetic spring and the second electromagnetic spring is opposite to the displacement direction of the main magnetic steel. The direction of spring resultant force of the electromagnetic spring is opposite to the displacement direction of the main magnetic steel, so that the main magnetic steel is always subjected to restoring force towards a reciprocating motion center in the motion process, a compression piston of the linear compressor can be assisted to automatically return to the center, the piston offset resistance of the linear compressor is improved, and the cylinder collision risk is effectively reduced; and the electromagnetic spring does not have the material fatigue fracture risk of a traditional mechanical spring and can normally work for a long time at the demagnetization temperature, and the reliability is further improved.

Description

Technical Field

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

[0002] As the pressure wave generator of Stirling refrigerator and pulse tube refrigerator, linear compressor is widely used in military and civilian scenarios such as infrared detection, infrared night vision, infrared guidance, etc. in space and on the ground.

[0003] According to the type of linear motor, linear compressors can be divided into moving magnet type, moving coil type and moving iron type, among which the moving magnet type is the most widely used in engineering. Linear compressors use linear motors to directly drive the piston to perform reciprocating linear motion, and its piston is usually connected to the stator by a mechanical spring. On the one hand, the mechanical spring provides an alternating spring force to participate in the reciprocating motion of the piston, and on the other hand, it also provides a constant spring force to constrain the equilibrium position of the piston near the initial equilibrium position to avoid contact with the limiter and collision with the cylinder. The piston and cylinder of the linear compressor adopt a gap sealing structure. During operation, the equilibrium position of the piston will deviate from the initial equilibrium position, which is called the piston offset phenomenon. One of the reasons for this phenomenon is that the time-averaged mass flux through the free piston sealing gap is not 0 and a net leakage to the back pressure chamber is generated, causing a pressure difference between the working chamber and the back pressure chamber, and the piston is offset under the action of the gas force. In addition, conventional moving magnet linear motors have an inevitable end effect. When the stroke approaches the limit, the motor bias force increases rapidly, causing the piston offset to increase rapidly, exacerbating the risk of collision with the cylinder. When the piston of a linear compressor is offset, the top and bottom dead points of the piston movement will be offset in the same direction, and the deformation of the mechanical spring at the same output power will increase, which will cause the stress on the leaf spring to exceed the maximum allowable stress, resulting in a reduced life of the leaf spring or even a break. The piston offset reduces the actual maximum stroke of the piston, which will reduce the maximum output power of the linear compressor. The piston offset will also cause the linear motor to deviate from the optimal operating position, reducing the output efficiency of the compressor. The piston offset will cause the cylinder to collide, resulting in damage or even breakage of the mechanical structure, seriously affecting reliability. Therefore, the piston offset problem is a common and urgent key technical problem in linear compressors. Summary of the invention

[0004] The object of the present invention is to provide a linear motor and a linear compressor for a linear compressor, which can improve the linear compressor's ability to resist piston deviation, effectively reduce the risk of cylinder collision, and avoid damage to the mechanical structure due to collision.

[0005] To achieve the above object, the technical solution of the present invention is a linear motor of a linear compressor, which includes a stator assembly and a mover assembly. The mover assembly includes a main magnet, and the main magnet makes a reciprocating motion under the action of a magnetic field excited after the stator assembly is energized. It further includes an electromagnetic spring, and the electromagnetic spring includes a first electromagnetic spring and a second electromagnetic spring arranged on both axial sides of the main magnet, and the direction of the resultant spring force of the first electromagnetic spring and the second electromagnetic spring is opposite to the displacement direction of the main magnet.

[0006] As one of the implementation manners, the first electromagnetic spring includes a left moving sub-magnet and a left fixed sub-magnet that repel each other magnetically, and the second electromagnetic spring includes a right moving sub-magnet and a right fixed sub-magnet that repel each other magnetically. The left moving sub-magnet and the right moving sub-magnet are arranged on both sides of the main magnet and move together with the main magnet. The left fixed sub-magnet is fixed on the side of the left moving sub-magnet away from the main magnet, and the right fixed sub-magnet is fixed on the side of the right moving sub-magnet away from the main magnet.

[0007] As one of the implementation manners, the magnetization direction of the main magnet is radial magnetization, and the left moving sub-magnet, the right moving sub-magnet, the left fixed sub-magnet, and the right fixed sub-magnet are all axially magnetized.

[0008] As one of the implementation manners, the magnetization directions of the left fixed sub-magnet and the left moving sub-magnet are opposite, the magnetization directions of the right fixed sub-magnet and the right moving sub-magnet are opposite, and the magnetization directions of the left moving sub-magnet and the right moving sub-magnet are opposite.

[0009] As one of the implementation manners, the left fixed sub-magnet is fixed on the stator assembly or the housing of the linear compressor, and the right fixed sub-magnet is fixed on the stator assembly or the cylinder block of the linear compressor.

[0010] As one of the implementation manners, the mover assembly further includes a magnet skeleton; the main magnet, the left moving sub-magnet, and the right moving sub-magnet are all arranged inside the magnet skeleton, or the main magnet, the left moving sub-magnet, and the right moving sub-magnet are all arranged outside the magnet skeleton.

[0011] As one of the implementation manners, the stator assembly includes a stator skeleton, an outer magnetic yoke, an inner magnetic yoke, and a coil winding. The outer magnetic yoke is fixed on the stator skeleton, and the coil winding is arranged in the outer magnetic yoke.

[0012] As one of the implementation manners, the outer magnetic yoke and the coil winding are both arranged outside the stator skeleton, or the outer magnetic yoke and the coil winding are both arranged inside the stator skeleton.

[0013] The present invention also provides a linear compressor, which includes a housing, a cylinder block and a compression piston. The cylinder block is provided with a compression chamber, and the compression piston is slidably arranged in the compression chamber; the linear motor as described in any one of the above is further included, and the main permanent magnet is connected to the compression piston.

[0014] As one of the implementation manners, there are two linear motors which are symmetrically arranged on both sides of the cylinder block. Two compression pistons are arranged in the compression chamber, and the two compression pistons are respectively connected to the two linear motors.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) In the present invention, a first electromagnetic spring and a second electromagnetic spring are respectively arranged on both sides of the main permanent magnet in the axial direction, and the direction of the resultant spring force of the first electromagnetic spring and the second electromagnetic spring is opposite to the displacement direction of the main permanent magnet, so that the main permanent magnet is always subjected to a restoring force towards the center of reciprocating motion during the movement process, which can assist the compression piston of the linear compressor to automatically return to the center, improve the ability of the linear compressor to resist piston offset, thereby effectively reducing the risk of cylinder collision and avoiding damage to the mechanical structure due to impact;

[0017] (2) The electromagnetic spring of the present invention can form a negative spring stiffness with almost a constant value within a certain stroke, and forms a rapidly increasing negative electromagnetic stiffness when approaching the limit stroke, greatly reducing the risk of cylinder collision;

[0018] (3) The electromagnetic spring of the present invention can effectively resist piston offset throughout the entire stroke, and the effective stroke of the compression piston is greatly increased, approximately approaching the designed stroke, greatly improving the output power of the linear compressor;

[0019] (4) The electromagnetic spring of the present invention does not have the risk of material fatigue fracture of traditional mechanical springs, and can work normally for a long time at the demagnetization temperature, further improving the reliability; and the electromagnetic spring uses magnetic force to resist piston offset, and it hardly consumes any energy;

[0020] (5) The piston of the linear compressor of the present invention has a small offset, the linear motor always works within the best position, and the motor efficiency is high; and the electromagnetic spring can achieve a fixed value of electromagnetic stiffness within about 80% of the designed stroke, so that the linear compressor can always operate at a certain best frequency, and the output efficiency of the compressor is high;

[0021] (6) The linear compressor of the present invention has a simple and compact structure, a shorter axial dimension, a lighter weight and a lower cost. Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0023] Figure 1 It is a schematic structural diagram of a conventional moving-magnet linear compressor;

[0024] Figure 2 It is a schematic structural diagram of a linear compressor provided by an embodiment of the present invention;

[0025] Figure 3 It is a schematic structural diagram of a linear compressor provided by an embodiment of the present invention;

[0026] Figure 4 It is a schematic structural diagram of a linear compressor provided by an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the magnetization directions of the main magnet, the left moving secondary magnet, the right moving secondary magnet, the left fixed secondary magnet, and the right fixed secondary magnet provided by an embodiment of the present invention;

[0028] Figure 6 It is a comparison diagram of the axial electromagnetic spring forces between the linear compressor provided by an embodiment of the present invention and a conventional moving-magnet linear compressor;

[0029] In the figure: 1. Outer shell; 2. Magnet skeleton; 3. Compression piston; 4. Left fixed secondary magnet; 5. Left secondary magnet fixing frame; 6. Left moving secondary magnet; 7. Stator skeleton; 8. Protection cylinder; 9. Outer yoke; 10. Coil winding; 11. Inner yoke; 12. Main magnet; 13. Right moving secondary magnet; 14. Right fixed secondary magnet; 15. Cylinder seat. Detailed implementation manners

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0032] The terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0033] As Figures 2 - 4 shown, this embodiment provides a linear motor of a linear compressor, including a stator assembly and a mover assembly. The mover assembly includes a main permanent magnet 12, and the main permanent magnet 12 makes a reciprocating motion under the action of the magnetic field excited after the stator assembly is electrified; it further includes an electromagnetic spring. The electromagnetic spring includes a first electromagnetic spring and a second electromagnetic spring arranged on both axial sides of the main permanent magnet 12, and the direction of the resultant spring force of the first electromagnetic spring and the second electromagnetic spring is opposite to the displacement direction of the main permanent magnet 12.

[0034] In this embodiment, the first electromagnetic spring and the second electromagnetic spring are respectively arranged on both axial sides of the main permanent magnet 12, and the direction of the resultant spring force of the first electromagnetic spring and the second electromagnetic spring is opposite to the displacement direction of the main permanent magnet 12, so that the main permanent magnet 12 is always subjected to a restoring force towards the reciprocating motion center (initial balance center) during the motion process, which can assist the compression piston 3 of the linear compressor to automatically return to the center, improve the ability of the linear compressor to resist piston offset, thereby effectively reducing the risk of cylinder collision and avoiding damage to the mechanical structure due to impact; moreover, the electromagnetic spring does not have the risk of material fatigue fracture of the traditional mechanical spring and can work normally for a long time at the demagnetization temperature, further improving the reliability.

[0035] In some embodiments, the first electromagnetic spring includes a moving secondary magnet 6 and a left fixed secondary magnet 4 that repel each other magnetically, the second electromagnetic spring includes a right moving secondary magnet 13 and a right fixed secondary magnet 14 that repel each other magnetically, the left moving secondary magnet 6 and the right moving secondary magnet 13 are arranged on both sides of the main magnet 12 and move together with the main magnet 12, the left fixed secondary magnet 4 is fixed on the side of the left moving secondary magnet 6 away from the main magnet 12, and the right fixed magnet 14 is fixed on the side of the right moving secondary magnet 13 away from the main magnet 12. Among them, the left moving secondary magnet 6 and the right moving secondary magnet 13 reciprocate together with the main magnet 12, which is different from the left fixed secondary magnet 4 and the right fixed magnet 14 that remain fixed. Optimally, the left moving secondary magnet 6 and the right moving secondary magnet 13 are symmetrically arranged on both sides of the main magnet 12, and the left fixed secondary magnet 4 and the right fixed secondary magnet 14 are symmetrically fixed on both sides of the main magnet 12.

[0036] Optimizing the above embodiment, the magnetization direction of the main magnet 12 is radial magnetization, and the left moving secondary magnet 6, the right moving secondary magnet 13, the left fixed secondary magnet 4, and the right fixed secondary magnet 14 are all axially magnetized. By radially magnetizing the main magnet 12 and axially magnetizing the left moving secondary magnet 6, the right moving secondary magnet 13, the left fixed secondary magnet 4, and the right fixed secondary magnet 14, the electromagnetic spring can form a nearly constant negative spring stiffness within a certain stroke and a negatively exponentially increasing spring stiffness when approaching the limit stroke. Therefore, when the piston stroke is large and the piston offset is close to hitting the cylinder, the electromagnetic spring can provide a stronger restoring force to resist the piston offset, greatly reducing the risk of hitting the cylinder.

[0037] In this embodiment, the main magnet 12, the left moving secondary magnet 6, the right moving secondary magnet 13, the left fixed secondary magnet 4, and the right fixed secondary magnet 14 are all made of permanent magnet materials. The permanent magnet materials are preferably neodymium iron boron rare earth materials. The main magnet 12, the left moving secondary magnet 6, the right moving secondary magnet 13, the left fixed secondary magnet 4, and the right fixed secondary magnet 14 can specifically adopt magnetic rings with geometric cross-sections such as circular and square; and since it is difficult to radially magnetize the magnetic ring, it is usually divided into 6 or 8 sectors and spliced into a complete ring, which has a high cost, and the sector rings repel each other during assembly, resulting in difficult assembly and poor accuracy. However, axial magnetization does not have this problem, and it can be magnetized as a complete ring, and the assembly is simple. Therefore, the main magnet 12 usually adopts a structure of multiple magnetic tiles spliced into a complete ring, and the left moving secondary magnet 6, the right moving secondary magnet 13, the left fixed secondary magnet 4, and the right fixed secondary magnet 14 can adopt an integral complete ring structure or a complete ring structure spliced by multiple pieces. The cross-sectional dimensions and axial lengths of the moving secondary magnet and the fixed secondary magnet can be set according to actual situations.

[0038] Preferably, the magnetization directions of the left fixed sub-magnet 4 and the left moving sub-magnet 6 are opposite, the magnetization directions of the right fixed sub-magnet 14 and the right moving sub-magnet 13 are opposite, and the magnetization directions of the left moving sub-magnet 6 and the right moving sub-magnet 13 are opposite, so as to ensure that a repulsive force can be generated between the corresponding moving sub-magnets and the fixed sub-magnets. In this embodiment, there are preferably four implementation manners for the magnetization directions of the main magnet 12, the left moving sub-magnet 6, the right moving sub-magnet 13, the left fixed sub-magnet 4, and the right fixed sub-magnet 14:

[0039] As Figure 5 shown in (1) below, the magnetization direction of the main magnet 12 is from the inside to the outside along its radial direction, the magnetization directions of the left fixed sub-magnet 4 and the left moving sub-magnet 6 are opposite, and the magnetization directions of the right moving sub-magnet 13 and the right fixed sub-magnet 14 are opposite;

[0040] As Figure 5 shown in (2) below, the magnetization direction of the main magnet 12 is from the outside to the inside along its radial direction, the magnetization directions of the left fixed sub-magnet 4 and the left moving sub-magnet 6 are opposite, and the magnetization directions of the right moving sub-magnet 13 and the right fixed sub-magnet 14 are opposite;

[0041] As Figure 5 shown in (3) below, the magnetization direction of the main magnet 12 is from the inside to the outside along its radial direction, the magnetization directions of the left fixed sub-magnet 4 and the left moving sub-magnet 6 are opposite, and the magnetization directions of the right moving sub-magnet 13 and the right fixed sub-magnet 14 are opposite;

[0042] As Figure 5 shown in (4) below, the magnetization direction of the main magnet 12 is from the outside to the inside along its radial direction, the magnetization directions of the left fixed sub-magnet 4 and the left moving sub-magnet 6 are opposite, and the magnetization directions of the right moving sub-magnet 13 and the right fixed sub-magnet 14 are opposite.

[0043] Furthermore, the left fixed sub-magnet is fixed on the stator assembly or the housing of the linear compressor, and the right fixed sub-magnet is fixed on the stator assembly or the cylinder seat of the linear compressor. In this embodiment, there are various ways to install the left fixed sub-magnet 4 and the right fixed sub-magnet 14. The left fixed sub-magnet 4 can be fixed on the housing 1, the left end of the outer magnetic yoke 9, or the stator skeleton 7, and the right fixed sub-magnet 14 can be fixed on the right end of the inner magnetic yoke 11, the right end of the outer magnetic yoke 9, or the end face of the cylinder seat 15 of the linear compressor. The left fixed sub-magnet 4 and the right fixed sub-magnet 14 can be specifically fixed by means such as glue bonding, screw connection, laser welding, etc. Specifically, as Figure 2 and Figure 3As shown, when both the outer yoke 9 and the coil winding 10 are disposed outside the stator skeleton 7, the left fixed sub-magnet 4 can be fixed to the left sub-magnet fixing bracket 5 with glue and connected and fixed to the stator skeleton 7 with screws, or can be directly fixed to the stator skeleton 7 or the housing 1. The right fixed sub-magnet 14 can be directly fixed to the stator skeleton 7 or the cylinder block 15 of the linear compressor; as Figure 4 As shown, when both the outer yoke 9 and the coil winding 10 are disposed inside the stator skeleton 7, the left fixed sub-magnet 4 can be directly fixed to the stator skeleton 7 or the left end of the outer yoke 9, and the right fixed sub-magnet 14 can be directly fixed to the right end of the inner yoke 11, the right end of the outer yoke 9 or the cylinder block 15 of the linear compressor.

[0044] As Figures 2 - 4 shown, the mover assembly further includes a magnet skeleton 2. In some embodiments, the main magnet 12, the left moving sub-magnet 6, and the right moving sub-magnet 13 are all disposed inside the magnet skeleton 2, as Figure 2 and Figure 4 shown. In some other embodiments, the main magnet 12, the left moving sub-magnet 6, and the right moving sub-magnet 13 are all disposed outside the magnet skeleton 2, as Figure 3 shown. The main magnet 12, the left moving sub-magnet 6, and the right moving sub-magnet 13 can be specifically fixed to the inside or outside of the magnet skeleton 2 by means of glue bonding, screw connection, laser welding, or end pressing.

[0045] In this embodiment, the stator assembly includes a stator skeleton 7, an outer yoke 9, an inner yoke 11, and a coil winding 10. The outer yoke 9 is fixed to the stator skeleton 7, and the coil winding 10 is disposed in the outer yoke 9. Specifically, both the outer yoke 9 and the inner yoke 11 are made of soft iron material. A circumferential groove is provided on the inner wall of the outer yoke 9, and the coil winding 10 is installed in this groove; the outer yoke 9 and the inner yoke 11 are respectively disposed outside and inside the main magnet 12, and the inner yoke 11 is fixed to the cylinder block 15 of the linear compressor.

[0046] In some embodiments, both the outer yoke 9 and the coil winding 10 are disposed outside the stator skeleton 7. As Figure 2 and Figure 3 shown, a limiting structure is provided on the outside of the left end of the stator skeleton 7. The outer yoke 9 is installed between the limiting structure at the left end of the stator skeleton 7 and the cylinder block 15 of the linear compressor, and is fixed to the outer wall of the stator skeleton 7 by means of gluing or welding. At this time, the coil winding 10 is isolated from the gas flow channel inside the linear compressor. A protection cylinder 8 is provided on the outside of the outer yoke 9, and both ends of the protection cylinder 8 are respectively connected to the limiting structure at the left end of the stator skeleton 7 and the cylinder block 15 of the linear compressor.

[0047] In some other embodiments, both the outer magnetic yoke 9 and the coil winding 10 are disposed inside the stator skeleton 7. As Figure 4 shown, a limiting structure is provided inside the left end of the stator skeleton 7. The outer magnetic yoke 9 is installed between the limiting structure at the left end of the stator skeleton 7 and the cylinder block 15 of the linear compressor, and is fixed to the inner wall of the stator skeleton 7 by means of gluing or welding. At this time, the coil winding 10 communicates with the gas flow channel inside the linear compressor.

[0048] The present invention also provides a linear compressor, including a housing 1, a cylinder block 15 and a compression piston 3. The cylinder block 15 is provided with a compression chamber, and the compression piston 3 is slidably disposed in the compression chamber; it further includes the linear motor according to any one of the above. The main permanent magnet 12 is connected to the compression piston 3. The linear compressor of this embodiment adopts the above linear motor, and connects the main permanent magnet 12 with the compression piston 3. The electromagnetic spring can provide a centering force for the piston offset throughout the entire stroke, thereby effectively resisting the piston offset, reducing the risk of cylinder collision, avoiding mechanical structure impact damage, and improving the reliability of the linear compressor; and this embodiment adopts a structurally compact electromagnetic spring, without the need to adopt expensive traditional mechanical springs (especially leaf springs), solving the problem of large axial displacement requirements of traditional mechanical springs, making the compressor structure simple and compact, with a shorter axial dimension and lighter weight.

[0049] Among them, a clearance seal is adopted between the compression piston 3 and the cylinder block 15, and the unilateral clearance is usually less than 10 um; the compression piston 3 is fixed to the magnet skeleton 2 by means of welding, glue bonding or threaded connection, etc. and reciprocates under its drive to complete the compression and expansion processes in sequence.

[0050] The working principle of the linear compressor of this embodiment is as follows: when an alternating current is applied to the coil winding 10, an alternating magnetic field will be excited in the outer magnetic yoke 9, the inner magnetic yoke 11 and the air gap. The main permanent magnet 12, the left moving secondary permanent magnet 6 and the right moving secondary permanent magnet 13 make reciprocating motions under the action of the magnetic field, and drive the compression piston 3 to perform periodic compression and expansion. The gas is periodically inhaled and discharged through the flow channel to generate a pressure wave. During this process, a spring resultant force opposite to the displacement direction of the main permanent magnet 12 is generated by the interaction with the left fixed secondary permanent magnet 4 and the right fixed secondary permanent magnet 14. This electromagnetic spring is equivalent to a mechanical spring, and has the function of periodically recovering and releasing mechanical work and assisting the mover assembly to return to the center of reciprocating motion and resisting piston offset.

[0051] Figure 6 shows the axial electromagnetic spring force of the linear compressor of the present invention and Figure 1The axial spring force relationship of the moving magnet linear compressor in the conventional solution. It can be seen that when the displacement of the linear compressor of the present invention is positive, the resultant spring force of the electromagnetic spring is negative, and its slope (i.e., the electromagnetic spring stiffness) is negative, which functions to pull the piston mover back to the initial equilibrium center; and Figure 1 when the displacement of the conventional moving magnet linear compressor is positive, the spring force is also positive, which will exacerbate the deviation of the piston mover from the initial equilibrium center and cause cylinder collision. When the piston stroke of the linear compressor of the present invention does not exceed 80% of the full stroke, its electromagnetic spring stiffness (the slope in the figure) is almost a constant negative value, and the optimal operating frequency of the compressor remains unchanged, enabling high-efficiency operation; when the piston stroke exceeds 80% of the full stroke, its electromagnetic spring stiffness is a rapidly increasing negative value, and the electromagnetic spring force at full stroke can reach more than 20 N, which can effectively resist piston offset and avoid cylinder collision.

[0052] In some embodiments, there are two linear motors symmetrically arranged on both sides of the cylinder block 15. Two compression pistons 3 arranged coaxially are provided in the compression chamber, and the two compression pistons 3 are respectively connected to the magnet skeletons 2 of the two linear motors, forming an opposed linear compressor. Since the two motors are symmetrically arranged, the movements of the two compression pistons 3 are also symmetrical, which can improve the compression efficiency and operating stability of the compressor.

[0053] It should be noted that Figures 2 - 4 only the embodiments of the opposed linear compressor are shown. In some other embodiments, there is one linear motor arranged on one side of the cylinder block 15, one compression piston 3 is provided in the compression chamber, and the compression piston 3 is connected to the magnet skeleton 2 of the linear motor; in other embodiments, the linear motor may also include multiple linear motors and multiple compression pistons 3.

[0054] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A linear motor of a linear compressor, comprising a stator assembly and a mover assembly. The mover assembly includes a main permanent magnet, which makes a reciprocating motion under the action of a magnetic field excited after the stator assembly is powered on. It is characterized in that: It further includes electromagnetic springs, which include a first electromagnetic spring and a second electromagnetic spring disposed on both axial sides of the main permanent magnet. The direction of the resultant spring force of the first electromagnetic spring and the second electromagnetic spring is opposite to the displacement direction of the main permanent magnet.

2. The linear motor according to claim 1, characterized in that: The first electromagnetic spring includes a left moving sub-permanent magnet and a left fixed sub-permanent magnet that repel each other magnetically. The second electromagnetic spring includes a right moving sub-permanent magnet and a right fixed sub-permanent magnet that repel each other magnetically. The left moving sub-permanent magnet and the right moving sub-permanent magnet are disposed on both sides of the main permanent magnet and move together with the main permanent magnet. The left fixed sub-permanent magnet is fixed on the side of the left moving sub-permanent magnet away from the main permanent magnet, and the right fixed sub-permanent magnet is fixed on the side of the right moving sub-permanent magnet away from the main permanent magnet.

3. The linear motor according to claim 2, wherein: The magnetization direction of the main permanent magnet is radial magnetization, and the left moving sub-permanent magnet, the right moving sub-permanent magnet, the left fixed sub-permanent magnet, and the right fixed sub-permanent magnet are all axially magnetized.

4. The linear motor according to claim 3, characterized in that: The magnetization directions of the left fixed sub-permanent magnet and the left moving sub-permanent magnet are opposite, the magnetization directions of the right fixed sub-permanent magnet and the right moving sub-permanent magnet are opposite, and the magnetization directions of the left moving sub-permanent magnet and the right moving sub-permanent magnet are opposite.

5. The linear motor according to claim 2, wherein: The left fixed sub-permanent magnet is fixed on the stator assembly or the housing of the linear compressor, and the right fixed sub-permanent magnet is fixed on the stator assembly or the cylinder block of the linear compressor.

6. The linear motor according to claim 2, characterized in that: The mover assembly further includes a magnet skeleton; the main permanent magnet, the left moving sub-permanent magnet, and the right moving sub-permanent magnet are all disposed inside the magnet skeleton, or the main permanent magnet, the left moving sub-permanent magnet, and the right moving sub-permanent magnet are all disposed outside the magnet skeleton.

7. The linear motor according to claim 1, characterized in that: The stator assembly includes a stator skeleton, an outer magnetic yoke, an inner magnetic yoke, and a coil winding. The outer magnetic yoke is fixed on the stator skeleton, and the coil winding is disposed in the outer magnetic yoke.

8. The linear motor according to claim 7, wherein: The outer magnetic yoke and the coil winding are both disposed outside the stator skeleton, or the outer magnetic yoke and the coil winding are both disposed inside the stator skeleton.

9. A linear compressor, comprising a housing, a cylinder block and a compression piston, wherein the cylinder block is provided with a compression chamber, and the compression piston is slidably disposed in the compression chamber; characterized in that: It further includes the linear motor according to any one of claims 1-8, and the main permanent magnet is connected to the compression piston.

10. The linear compressor according to claim 9, characterized in that: There are two linear motors, which are symmetrically disposed on both sides of the cylinder block. Two compression pistons are disposed in the compression chamber, and the two compression pistons are respectively connected to the two linear motors.

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