Axial magnetic flux stator core, permanent magnet motor, compressor and electric appliance

Abstract

The invention provides an axial magnetic flux stator core, a permanent magnet motor, a compressor and an electric appliance, the axial magnetic flux stator core is provided with a plurality of tooth parts, the plurality of tooth parts are uniformly arranged along the circumferential direction of the stator core, and a stator slot is formed between two adjacent tooth parts; a first yoke part is arranged on the outer peripheral wall of the stator core corresponding to each stator slot in the radial direction of the stator core; the first yoke part is provided with a magnetic isolation through hole, and the magnetic isolation through hole extends along the axial direction of the stator core. According to the stator iron core with the axial magnetic flux, the iron core ferromagnetic property change caused by pressure stress after the shell is thermally sleeved is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular, to a stator core with an axial magnetic flux, a permanent magnet motor using the stator core with an axial magnetic flux, a compressor using the permanent magnet motor, and an electrical appliance using the compressor. Background Art

[0002] Among many refrigeration household appliances, such as refrigerators, air conditioners, and air purifiers, compressors are required. In the compressor structure, the permanent magnet motor is the core component that provides compression power for the pump body and is an important embodiment of compressor technology. As compressors develop towards miniaturization and high efficiency, permanent magnet motors are bound to continue to explore and improve in this direction.

[0003] In the formulation of conventional radial flux compressor motor solutions, as the compressor displacement increases, in order to enable the motor to drive a larger cylinder and obtain stronger power, the motor plate type and the number of winding turns also need to be changed accordingly. However, the production and manufacturing of compressors are highly serialized. The same series of compressors use the same motor outer diameter. When using the same plate type motor, the larger the compressor displacement, the higher the motor stack height will be. As the motor stack height increases, the difficulty of controlling the verticality of the core will increase, and the difficulty of motor winding will also increase simultaneously. In the compressor structure, the motor volume occupies a large space of the compressor, which to a certain extent limits the update of the pump body structure and the development of compressor miniaturization. Therefore, seeking a solution to ensure the compressor displacement and minimize the motor volume has also become an important direction for the development of compressors.

[0004] In order to overcome the above problems, an existing motor stator core structure adopts an axial flux design, that is, the direction of the magnetic field generated by the winding when the motor using this structure is running is axial. This design increases the effective area of ​​the motor winding and the permanent magnet, reduces magnetic leakage, and has the advantages of high torque density, high power, and less permanent magnet compared to the traditional radial flux motor. The axial flux motor is smaller in size and has a higher output torque. The space saved by reducing the motor volume is conducive to the improvement of the compressor pump body structure and the miniaturization design of the compressor.

[0005] Existing compressors usually use the shrink-fit shell manufacturing process. The impact of the shrink-fit shell manufacturing process on the stator iron loss has always been a concern. After the compressor motor is shrink-fitted, the compressive stress exerted by the shell on the stator core mainly acts on the stator yoke, which is the main channel of the magnetic circuit and is in a high magnetic density area, resulting in an increase in the iron loss of the motor yoke under compressive stress. The experimental results show that compared with the case without shrink-fitting, under the influence of compressive stress, the iron loss of the motor increases sharply after the shrink-fit shell is matched, among which: the no-load iron loss increases by about 1.3 times, the load iron loss increases by about 1.7 times, and the motor efficiency decreases by about 1.7% in the experiment.

[0006] Therefore, a more optimized motor structure needs to be considered. Summary of the invention

[0007] The first object of the present invention is to provide a stator core which can reduce the change of the ferromagnetic properties of the core due to the compressive stress after shrink-fitting the shell.

[0008] The second object of the present invention is to provide a permanent magnet motor which can reduce the change of the ferromagnetic properties of the core due to compressive stress after shrink-fitting the shell.

[0009] A third object of the present invention is to provide a compressor which can reduce the change of the ferromagnetic properties of the core due to compressive stress after shrink-fitting the shell.

[0010] A fourth object of the present invention is to provide an electrical appliance which can reduce the change in the ferromagnetic properties of the core due to compressive stress after shrink-fitting the housing.

[0011] In order to achieve the above-mentioned first purpose, the stator core of axial magnetic flux provided by the present invention is provided with a plurality of teeth, and the plurality of teeth are evenly arranged along the circumferential direction of the stator core, and a stator slot is formed between two adjacent teeth; each stator slot is provided with a first yoke on the outer peripheral wall of the stator core corresponding to the radial direction of the stator core; the first yoke is provided with a magnetic isolation hole, and the magnetic isolation hole extends along the axial direction of the stator core.

[0012] It can be seen from the above scheme that the stator core of the axial magnetic flux of the present invention can guide the magnetic circuit to take the minimum path and effectively reduce the iron loss by arranging magnetic isolation holes on the yoke. At the same time, the first yoke at the magnetic isolation holes can produce a slight deformation after being heat-shrink-fitted into the shell to offset part of the compressive stress of the shell on the core, thereby reducing the change of the ferromagnetic properties of the core caused by the compressive stress after being heat-shrink-fitted into the shell.

[0013] In a further scheme, on the cross section of the stator core, the magnetic isolation hole is surrounded by a first arc, a second arc, a third arc and a fourth arc. The first arc and the second arc are arranged opposite to each other in the circumferential direction of the stator core, the third arc and the fourth arc are arranged opposite to each other and in parallel in the radial direction of the stator core, and the fourth arc is located on the side close to the axial centerline of the stator core; the first arc takes the intersection of the first radial extension line of the stator slot corresponding to the magnetic isolation hole and the symmetrical arc of the magnetic isolation hole as the center of the circle, the first radial extension line is the extension line of the first side line of the stator slot extending radially along the stator core, and the symmetrical arc is the arc connecting the center point of the first arc and the center point of the second arc and parallel to the third arc; the second arc takes the intersection of the second radial extension line of the stator slot corresponding to the magnetic isolation hole and the symmetrical arc as the center of the circle, and the second radial extension line is the extension line of the second side line of the stator slot extending radially along the stator core.

[0014] It can be seen that the size setting of the magnetic isolation through hole can ensure that the magnetic isolation through hole effectively isolates the magnetic field without affecting the normal magnetic circuit.

[0015] In a further solution, in the radial direction of the stator core, the distance between the symmetrical arc line and the fourth arc line is 0.68 mm to 0.72 mm.

[0016] In a further solution, the magnetic isolation through holes are spaced into multiple sections of through holes in the circumferential direction of the stator core.

[0017] It can be seen that dividing the magnetic isolation through holes into multi-section through holes can enhance the strength of the yoke and avoid excessive deformation of the yoke.

[0018] In a further solution, a flow groove is provided between two adjacent first yokes on the outer peripheral wall of the stator core, and the flow groove extends along the axial direction of the stator core.

[0019] It can be seen that the axial flux motor has the advantages of compact structure, high power and large output torque, but it is also accompanied by the problems of heat generation and heat dissipation difficulties. Axial flux motors often require a separate cooling structure. The stator core yoke is provided with a flow groove, and the stator winding is completely exposed in the compressor cavity, which increases the contact area between the motor and the cooling medium. When the compressor is running, the cooling medium such as the refrigerant oil and refrigerant in the cavity is directly circulated through the winding to the flow groove, effectively reducing the winding temperature. At the same time, the flow groove can reduce the contact area between the stator and the compressor housing, reducing the impact of the heat-fitting housing on the motor performance.

[0020] In a further solution, the groove depth of the through-flow groove is equal to half of the outer diameter of the stator core minus the length of the arc of the groove bottom of the through-flow groove from the axis of the stator core.

[0021] In a further solution, the width of the through-flow groove is 28.4±0.05 mm, and the depth of the through-flow groove is 2.98±0.03 mm.

[0022] In a further solution, on the cross section of the stator core, the arc of the bottom of the current-carrying groove and the arc of the bottom surface of the magnetic isolation hole are located on the same circumference.

[0023] It can be seen that the size setting of the through-flow groove can ensure a balance between stator performance and effective cooling medium circulation.

[0024] In a further solution, the teeth are arranged in a stepless shoe shape.

[0025] It can be seen that the teeth are arranged in a stepless shoe shape, which can facilitate the installation of the winding.

[0026] In a further solution, on the cross section of the stator core, a first tooth arc is provided on the side of the tooth portion close to the outer periphery of the stator core, and a second tooth arc is provided on the side of the tooth portion close to the axial centerline of the stator core, and the center of the second tooth arc is located on the center line of the tooth portion extending radially along the stator core.

[0027] It can be seen that the first tooth arc and the second tooth arc are provided on the tooth portion, so that the winding coil can fit the tooth portion when installed.

[0028] In order to achieve the above second purpose, the permanent magnet motor provided by the present invention includes a stator core, a winding assembly and a rotor. The stator core and the rotor are installed in coordination, and the winding assembly is installed on the stator core. The stator adopts the above stator.

[0029] In order to achieve the third objective, the compressor provided by the present invention includes a permanent magnet motor, and the permanent magnet motor adopts the permanent magnet motor mentioned above.

[0030] In order to achieve the fourth objective, the present invention provides an electrical appliance, including a compressor, wherein the compressor is the above-mentioned compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural exploded view of the first embodiment of the permanent magnet motor of the present invention.

[0032] Figure 2 It is a structural diagram of the stator core in the first embodiment of the permanent magnet motor of the present invention.

[0033] Figure 3 It is a structural front view of the stator core in the direction of the teeth in the first embodiment of the permanent magnet motor of the present invention.

[0034] Figure 4 It is a front view of a part of the structure in the direction of the teeth of the stator core in the first embodiment of the permanent magnet motor of the present invention.

[0035] Figure 5 It is a structural diagram of the magnetic isolation through hole of the stator core in the first embodiment of the permanent magnet motor of the present invention.

[0036] Figure 6 yes Figure 5 Enlarged view of point A in the middle.

[0037] Figure 7 It is a structural diagram of the flow groove in the first embodiment of the permanent magnet motor of the present invention.

[0038] Figure 8 It is a structural schematic diagram of a stator core blank in the first embodiment of the permanent magnet motor of the present invention.

[0039] Fig. 9 It is a structural front view of the stator core in the direction of the teeth in the second embodiment of the permanent magnet motor of the present invention.

[0040] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0041] The first embodiment of permanent magnet motor:

[0042] As shown in the figure, in this embodiment, the permanent magnet motor includes an axial magnetic flux stator core 1, a winding assembly 2 and a rotor 3. The stator core 1 and the rotor 3 are installed in coordination, and the winding assembly 2 is installed on the stator core 1. The stator core 1 is cylindrical.

[0043] See also Figure 2 and Figure 3 The stator core 1 of the axial magnetic flux is provided with a plurality of teeth 11, and the plurality of teeth 11 are evenly arranged along the circumferential direction of the stator core 1, and a stator slot 12 is formed between two adjacent teeth 11. Each stator slot 12 is provided with a first yoke 13 on the outer peripheral wall of the stator core 1 corresponding to the radial direction of the stator core 1. The first yoke 13 is provided with a magnetic isolation hole 14, and the magnetic isolation hole 14 extends along the axial direction of the stator core 1. In this embodiment, the slot width a1 of the stator slot 12 is 16±0.02mm.

[0044] See also Figure 4 The tooth portion 11 is configured in a stepless shoe shape. By configuring the tooth portion 11 in a stepless shoe shape, the installation of the winding can be facilitated. The number of the tooth portions 11 can be set according to the size of the motor. In this embodiment, the number of the tooth portions 11 is nine.

[0045] On the cross section of the stator core 1, a first tooth arc 111 is provided on the side of the tooth 11 close to the outer periphery of the stator core 1, and a second tooth arc 112 is provided on the side of the tooth 11 close to the axis of the stator core 1, and the center of the second tooth arc 112 is located on the center line of the tooth 11 extending radially along the stator core 1. The tooth 11 is provided with the first tooth arc 111 and the second tooth arc 112, so that the winding coil fits the tooth 11 when it is installed. Preferably, the slot width of the stator slot 12 is 16±0.02mm, the distance between the center point of the first tooth arc 111 and the axis of the stator core 1 is 70±0.03mm, and the distance between the center point of the second tooth arc 112 and the axis of the stator core 1 is 40±0.03mm.

[0046] See also Figure 5 and Figure 6In the cross section of the stator core 1, the magnetic isolation hole 14 is surrounded by a first arc 141, a second arc 142, a third arc 143 and a fourth arc 144. The first arc 141 and the second arc 142 are arranged opposite to each other in the circumferential direction of the stator core 1, the third arc 143 and the fourth arc 144 are arranged opposite to each other and parallel to each other in the radial direction of the stator core 1, and the fourth arc 144 is located on the side close to the axis of the stator core 1. The first arc 141 takes the intersection of the first radial extension line of the stator slot 12 corresponding to the magnetic isolation hole 14 and the symmetrical arc 145 of the magnetic isolation hole 14 as the center of the circle. The first radial extension line is the extension line of the first side line 121 of the stator slot 12 extending radially along the stator core 1, and the symmetrical arc 145 is an arc connecting the center point of the first arc 141 and the center point of the second arc 142 and parallel to the third arc 143. The second arc 142 takes the intersection of the second radial extension line of the stator slot 12 corresponding to the magnetic isolation hole 14 and the symmetrical arc 145 as the center, and the second radial extension line is the extension line of the second edge line 122 of the stator slot 12 extending radially along the stator core 1. The size setting of the magnetic isolation hole 14 can ensure that the magnetic isolation hole 14 effectively isolates the magnetic field without affecting the normal magnetic circuit. Preferably, in the radial direction of the stator core 1, the distance between the symmetrical arc 145 and the fourth arc 144 is 0.68mm to 0.72mm.

[0047] In this embodiment, see Figure 7 On the outer peripheral wall of the stator core 1, a flow groove 15 is provided between two adjacent first yokes 13, and the flow groove 15 extends along the axial direction of the stator core 1. The axial flux motor has the advantages of compact structure, high power, and large output torque, but it is also accompanied by the problems of heat generation and heat dissipation. Axial flux motors often require a separate cooling structure. The yoke of the stator core 1 is provided with a flow groove 15, and the stator winding is completely exposed in the compressor cavity, which increases the contact area between the motor and the cooling medium. When the compressor is running, the cooling medium such as the refrigeration oil and refrigerant in the cavity is directly circulated through the winding to the flow groove 15, effectively reducing the winding temperature. At the same time, the flow groove 15 can reduce the contact area between the stator and the compressor housing, and reduce the impact of the shrink-fit housing on the motor performance.

[0048] In this embodiment, the groove depth of the through-flow groove 15 is equal to half of the outer diameter of the stator core 1 minus the length of the arc of the groove bottom of the through-flow groove 15 from the axis of the stator core 1. Preferably, the groove width a2 of the through-flow groove 15 is 28.4±0.05mm, and the groove depth of the groove bottom of the through-flow groove 15 is 2.98±0.03mm.

[0049] In this embodiment, on the cross section of the stator core 1, the bottom arc of the flow groove 15 and the bottom arc of the magnetic isolation hole 14 are on the same circumference, wherein the bottom arc of the magnetic isolation hole 14 is the fourth arc line 144. The size setting of the flow groove 15 can ensure the balance between stator performance and effective oil and gas circulation.

[0050] In addition, see Figure 8 The stator core 1 of the present embodiment adopts a non-oriented electrical steel strip 10, and a strip winding machine is used to wind the electrical steel strip 10. During the winding process, the strip layers are glued or spot welded to fix them so that the blank does not loosen, which is convenient for subsequent processing. This is a well-known technology for those skilled in the art and will not be repeated here. After the stator core blank is completed, it is subjected to stamping and other processing to obtain the structure of the stator core 1 of the present embodiment. The stator core 1 adopts the process of winding the stator core with a non-oriented electrical steel strip 10. The arrangement direction of the silicon steel is radial, which effectively suppresses the radial eddy currents generated by the axial alternating magnetic field. At the same time, the winding core process also reduces the difficulty of using special materials such as ultra-thin silicon steel and amorphous materials. The strip can be directly wound, which is more advantageous than the traditional stamping process.

[0051] The second embodiment of the permanent magnet motor:

[0052] The permanent magnet motor of this embodiment is different from the permanent magnet motor of the first embodiment only in the structural arrangement of the magnetic isolation through holes. Only the differences are described below, and the reference numerals are the same as those in the first embodiment.

[0053] See also Fig. 9 In this embodiment, the magnetic isolation holes 14 are spaced into multiple sections in the circumferential direction of the stator core 1. The magnetic isolation holes 14 are spaced into multiple sections to enhance the strength of the yoke at the magnetic isolation holes 14 and prevent the yoke from being deformed too much.

[0054] From the above, it can be seen that the stator core 1 of the axial magnetic flux of the present invention can guide the magnetic circuit to take the minimum path and effectively reduce the iron loss by arranging the magnetic isolation hole 14 on the yoke. At the same time, the first yoke 13 at the magnetic isolation hole 14 can produce a slight deformation after the shrink-fit shell process to offset part of the compressive stress of the shell on the core, thereby reducing the change of the ferromagnetic properties of the core due to the compressive stress after the shrink-fit shell process.

[0055] Compressor Example:

[0056] In this embodiment, the compressor includes a permanent magnet motor, and the permanent magnet motor adopts the permanent magnet motor of the above embodiment.

[0057] Electrical appliance embodiment:

[0058] In this embodiment, the electrical appliance includes a compressor, and the compressor adopts the compressor of the above embodiment. The electrical appliance may be a refrigerator, an air conditioner, an air purifier, or other electrical appliances that require a compressor.

[0059] It should be noted that the above are only preferred embodiments of the present invention, but the design concept of the invention is not limited thereto, and any non-substantial modifications made to the present invention using this concept also fall within the protection scope of the present invention.

Claims

1. A stator core with axial magnetic flux, provided with a plurality of teeth, the plurality of teeth are evenly arranged along the circumferential direction of the stator core, and a stator slot is formed between two adjacent teeth; characterized in that: Each of the stator slots is provided with a first yoke on the outer peripheral wall of the stator core corresponding to the stator core in the radial direction of the stator core; The first yoke is provided with a magnetic isolation through hole, and the magnetic isolation through hole extends along the axial direction of the stator core.

2. The stator core of axial magnetic flux according to claim 1, characterized in that: In the cross section of the stator core, the magnetic isolation through hole is surrounded by a first arc line, a second arc line, a third arc line and a fourth arc line, the first arc line and the second arc line are arranged opposite to each other in the circumferential direction of the stator core, the third arc line and the fourth arc line are arranged opposite to each other and parallel to each other in the radial direction of the stator core, and the fourth arc line is located on a side close to the axial center line of the stator core; The first arc line has the intersection of the first radial extension line of the stator slot corresponding to the magnetic isolation through hole and the symmetrical arc line of the magnetic isolation through hole as the center of the circle, the first radial extension line is the extension line of the first side line of the stator slot extending radially along the stator core, and the symmetrical arc line is the arc line connecting the center point of the first arc line and the center point of the second arc line and parallel to the third arc line; The second arc line has the intersection of the second radial extension line of the stator slot corresponding to the magnetic isolation hole and the symmetrical arc line as its center, and the second radial extension line is the extension line of the second side line of the stator slot extending radially along the stator core.

3. The stator core of axial magnetic flux according to claim 2, characterized in that: In the radial direction of the stator core, the distance between the symmetrical arc line and the fourth arc line is 0.68 mm to 0.72 mm.

4. The axial flux stator core according to claim 1, characterized in that: The magnetic isolation through holes are spaced apart into multiple-section through holes in the circumferential direction of the stator core.

5. The stator core of axial magnetic flux according to claims 1 to 4, characterized in that: On the outer peripheral wall of the stator core, a flow groove is provided between two adjacent first yoke parts, and the flow groove extends along the axial direction of the stator core.

6. The axial flux stator core according to claim 5, characterized in that: The groove depth of the through-flow groove is equal to half of the outer diameter of the stator core minus the length of the arc of the groove bottom of the through-flow groove from the axial center line of the stator core.

7. The axial flux stator core according to claim 6, characterized in that: The groove width of the through-flow groove is 28.4±0.05 mm, and the groove depth of the through-flow groove is 2.98±0.03 mm.

8. The axial flux stator core according to claim 5, characterized in that: On the cross section of the stator core, the bottom arc of the current-carrying groove and the bottom arc of the magnetic isolation through hole are located on the same circumference.

9. The stator core of axial magnetic flux according to any one of claims 1 to 4, characterized in that: The tooth portion is arranged in a stepless shoe shape.

10. The axial flux stator core according to claim 9, characterized in that: In the cross section of the stator core, a first tooth arc is provided on the side of the tooth portion close to the outer periphery of the stator core, a second tooth arc is provided on the side of the tooth portion close to the axial centerline of the stator core, and the center of the second tooth arc is located on the center line of the tooth portion extending radially along the stator core.

11. A permanent magnet motor, comprising a stator core, a winding assembly and a rotor, wherein the stator core and the rotor are mounted in cooperation, and the winding assembly is mounted on the stator core; characterized in that: The stator is the stator according to claim 10.

12. A compressor, comprising a permanent magnet motor, characterized in that: The permanent magnet motor adopts the permanent magnet motor described in claim 11.

13. An electrical appliance, comprising a compressor, characterized in that: The compressor is the compressor according to claim 12.

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