Patent ID: 12261484

The description of the reference numerals shown inFIG.1toFIG.3is provided as follows:

100motor,102stator assembly,1022stator core,1024stator slot,1026winding,1028stator protruding tooth,104rotor assembly,1042rotor core,1044permanent magnet, and1046mounting groove.

DETAILED DESCRIPTION OF THE DISCLOSURE

In order that the above-mentioned objectives, features and advantages of the present application can be understood more clearly, a further detailed description of the present application will be given below in connection with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other if there is no conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can also be implemented in other manners than those described herein. Therefore, the protection scope of the present application is not limited to the specific embodiments disclosed below.

A motor100, a compressor and a refrigeration device according to some embodiments of the present application are described below with reference toFIGS.1-5.

As shown inFIGS.1-3, an embodiment according to the first aspect of the present application provides a motor100, comprising: a stator assembly102and a rotor assembly104.

For example, as shown inFIG.1, the stator assembly102comprises a stator core1022provided with a stator slot1024. The rotor assembly104comprises a rotor core1042and a permanent magnet1044. The rotor core1042is provided with the permanent magnet1044. As shown inFIG.3, in a section perpendicular to an axis of the rotor core1042, the distance between the stator core1022and the rotor core1042is δ mm, the length of the permanent magnet1044in its own magnetization direction is h mm, the number of the stator slots1024is Q, and the intrinsic coercivity of the permanent magnet1044is Hcj kA/m, Hcj being less than or equal to 1800 kA/m. By further limiting the relationship between the distance between the stator core1022and the rotor core1042, the length of the permanent magnet1044in its own magnetization direction, the number of the stator slots1024, and the intrinsic coercivity of the permanent magnet, it is possible to adjust the strength of the demagnetization reverse magnetic field generated by energizing the motor100. In other words, the strength of the reverse magnetic field, which is generated by energizing the winding1026of the motor100to demagnetize the permanent magnet1044, can be adjusted, so that when the mass percentage of heavy rare earth elements in the permanent magnet is reduced or the permanent magnet1044is free of heavy rare earth elements (i.e., when the anti-demagnetization ability of the motor100cannot meet the requirement for compressor use), the strength of the demagnetization reverse magnetic field generated by energizing the motor100is reduced, and the utilization rate of the permanent magnet1044is improved.

For example, when the intrinsic coercivity Hcj of the permanent magnet1044is less than or equal to 1800, which is lower than the intrinsic coercivity of the permanent magnet containing heavy rare earth elements under the same circumstances, it is indicated that the mass percentage of heavy rare earth elements in the permanent magnet1044is relatively low, the manufacturing cost of the motor100is relatively low, and the anti-demagnetization ability of the motor100is decreased. Therefore, for the motor100provided by the present application, by arranging the stator slots1024by the number Q in the stator core1022, setting the distance between the stator core1022and the rotor core1042to δ mm, and making the numerical range of the length h mm of the permanent magnet1044in the its own magnetization direction satisfy 80×(43−Q)/Hcj≤h≤1.6+δ, the strength of the demagnetization reverse magnetic field generated by energizing the motor100is reduced, and thus the anti-demagnetization ability of the motor100is enhanced, so that the anti-demagnetization ability of the motor100can meet the requirement of demagnetization resistance for the operation of the compressor. At the same time, the reduction in the use of high-cost heavy rare earth raw materials and the increase in the utilization rate of the permanent magnet1044of the motor100also reduce the production cost of the motor100. That is, the motor100of the present application can meet the requirement for compressor use, with reduced use of heavy rare earth elements and decreased cost, leading to enhanced cost performance.

For example, the intrinsic coercivity of the permanent magnet1044referred to in the present application is the intrinsic coercivity of the permanent magnet1044at 20° C. The strength of the applied reverse magnetic field that causes the vector sum of the microscopic magnetic dipole moments inside the permanent magnet1044to decrease to zero is called the intrinsic coercivity of the magnet. The length of the permanent magnet1044in its own magnetization direction is the thickness of the permanent magnet1044, and the length of the permanent magnet1044in the axial direction of the rotor core is the length of the permanent magnet.

For example, the B-H curve of the permanent magnet (or the rare earth permanent magnet material) is shown inFIG.4. When the permanent magnet1044does not have an externally applied magnetic field, the working point of the permanent magnet1044is at the position of point P. When a reverse magnetic field is applied, the working point moves down along the B-H curve to the position of point W, and when the reverse magnetic field is removed, the working point returns along the return line of point W. When point W is located above the inflection point D of the B-H curve, i.e., when point W is located at any position shown by the Br1-D solid line inFIG.4, the return line coincides with the Br1-D solid line in the B-H curve, and the remanence is Br1. When point W is located below the inflection point D, i.e., when point W is located at any position shown by the D-W solid line inFIG.4, the return line of point W is parallel to the Br1-D solid line (i.e., the straight line segment of the B-H curve), as shown by the Br2-W dotted line inFIG.4, and at this time, the remanence is Br2, producing irreversible demagnetization, i.e., the demagnetization loss is the difference between Br1 and Br2.

As can be seen, there are three factors that affect the anti-demagnetization ability of the motor100, i.e., the magnitude of the absolute value of the intrinsic coercivity Hcj of the permanent magnet1044, the position of the working point of the permanent magnet, and the strength of the reverse magnetic field. The strength of the reverse magnetic field is the strength of the reverse magnetic field generated by energizing the winding of the motor100to demagnetize the permanent magnet. Hcj of the permanent magnet1044determines the magnitude of the value of the inflection point D. The larger the absolute value of Hcj is, the larger the H value (i.e., Hd) of the inflection point D is and the stronger the anti-demagnetization ability is. The smaller the absolute value of Hcj is, the smaller the Hd value of the inflection point D is and the weaker the anti-demagnetization ability is. The higher the position of the working point of the permanent magnet1044is, the stronger the anti-demagnetization ability is. The strength of the reverse magnetic field determines the distance by which the working point P moves down to W. When the working point position P remains unchanged, the reverse magnetic field is relatively strong, and the lower point W is, the weaker the anti-demagnetization ability is.

The magnitude of the intrinsic coercivity Hcj of the permanent magnet1044is positively correlated with the mass percentage of heavy rare earth elements in the permanent magnet1044. In other words, the larger the mass percentage of heavy rare earth elements in the permanent magnet1044is, the larger the intrinsic coercivity Hcj of the permanent magnet1044is, and the smaller the mass percentage of heavy rare earth elements in the permanent magnet1044is, the smaller the intrinsic coercivity Hcj of the permanent magnet1044is. However, since heavy rare earth elements are national strategic resources with high cost, enhancing the anti-demagnetization ability of the motor100by increasing the mass percentage of heavy rare earth elements in the permanent magnet1044has the problems of consuming national strategic resources and increasing the manufacturing cost of the motor100. If the manufacturing cost of the motor100is reduced by reducing the mass percentage of heavy rare earth elements in the permanent magnet1044or making the permanent magnet1044free of heavy metal elements, such as dysprosium and terbium, the intrinsic coercivity of the permanent magnet1044will be affected. Taking the permanent magnet1044free of dysprosium and terbium as an example, the intrinsic coercivity (Hcj≤1800 kA/m) of the permanent magnet free of dysprosium and terbium is significantly smaller than the coercivity (Hcj≥1830 kA/m) of the permanent magnet containing dysprosium and terbium. The B-H curves of permanent magnets free of dysprosium and terbium and permanent magnets containing dysprosium and terbium are shown inFIG.5. In the field of compressors, if the permanent magnets free of dysprosium and terbium are directly applied to some motors (such as 9-slot 6-pole motors), the demagnetization ability of the motors decreases by 40% or more, and the demagnetization ability of the motors cannot meet the requirement for compressor use.

For example, the B-H curves of permanent magnets free of dysprosium and terbium and permanent magnets containing dysprosium and terbium are shown inFIG.5. The solid line inFIG.5represents the demagnetization curve of an F42SH permanent magnet, wherein F42SH is a permanent magnet free of heavy rare earth, such as a neodymium iron boron permanent magnet free of dysprosium and terbium. The dotted lines inFIG.5represent the intrinsic demagnetization curve of the F42SH permanent magnet. The dashed lines with longer segments inFIG.5represent the demagnetization curve of an N54SH permanent magnet, wherein N54SH is a permanent magnet containing dysprosium and terbium. The dashed lines with shorter segments inFIG.5represent the intrinsic demagnetization curve of the N54SH permanent magnet. InFIG.5, the horizontal coordinate represents the magnetic field strength H in the permanent magnet, with the unit being KOe, i.e., kilo-oersted, and the vertical coordinate represents the magnetic induction strength B induced by the permanent magnet, with the unit being KGs, i.e., kilogauss. D1 inFIG.5represents the inflection point of the demagnetization curve of the F42SH permanent magnet, the magnetic field strength H(D1) corresponding to D1 is −8.177 KOe, and N1 is the intersection point of the intrinsic demagnetization curve of the F42SH permanent magnet and the horizontal coordinate, wherein the magnetic field strength H(N1) corresponding to N1 is −8.442 KOe. D2 inFIG.5represents the inflection point of the demagnetization curve of the N54SH permanent magnet, the magnetic field strength H(D2) corresponding to D2 is −11.085 KOe, and N2 is the intersection of the intrinsic demagnetization curve of the N54SH permanent magnet and the horizontal coordinate, wherein the magnetic field strength H(N2) corresponding to N2 is −11.454 KOe.

Since the main reason for the higher cost of a variable-frequency motor than a fixed-speed motor lies in the use of the permanent magnet1044, improving the utilization rate of the permanent magnet1044can reduce the usage of the permanent magnet1044and save the cost of the motor100. The utilization rate of the permanent magnet1044can reach its highest point when the working point of the permanent magnet1044is at a position with the maximum magnetic energy product of the permanent magnet1044. In other words, the closer the working point of the permanent magnet1044is to the position with the maximum magnetic energy product, the higher the utilization rate of the permanent magnet1044is. The position with the maximum magnetic energy product of the permanent magnet1044is generally the midpoint of the straight section of the demagnetization curve of the permanent magnet1044. Studies show that, on the one hand, in a section perpendicular to the rotation shaft of the permanent magnet1044, the larger the length h of the permanent magnet1044in its own magnetization direction is, the higher the working point of the permanent magnet1044is, and in the upper half of the B-H curve, the higher the working point is and the further the working point is from the point with the maximum magnetic energy product, the lower the utilization rate of the permanent magnet1044is. On the other hand, in the section perpendicular to the rotation shaft of the permanent magnet1044, the distance δ between the stator core1022and the rotor core1042of the motor100(i.e., the air gap between the stator assembly102and the rotor assembly104of the motor100) also affects the usage of the permanent magnet1044. The smaller the air gap width δ is, the lower the usage of the permanent magnet1044is. When the width of the permanent magnet1044is preset, the length h of the permanent magnet1044in its own magnetization direction is smaller.

In other words, in the section perpendicular to the rotation shaft of the permanent magnet1044, when the length h of the permanent magnet1044in its own magnetization direction is large, the working point of the permanent magnet1044is high, but the utilization rate of the permanent magnet1044is low; and when h is small, the utilization rate of the permanent magnet1044is high, but the working point of the permanent magnet1044is low, and the anti-demagnetization ability is poor.

Therefore, the present application enhances the anti-demagnetization ability of the motor100by reducing the strength of the demagnetization reverse magnetic field generated by energizing the motor100. Reducing the strength of the demagnetization reverse magnetic field generated by energizing the motor100is mainly to reduce the number of the turns of the winding1026in each stator slot1024, and the number of series turns of the winding per phase is equal to the number of turns per slot/2 (double-layer winding) multiplied by the number Q of the stator slots and then divided by the number m of phases. Thus, it can be known that increasing the number Q of the stator slots can reduce the number of the turns per slot of the winding, and when the number of the turns per slot is reduced, the strength of the reverse magnetic field is reduced, and the anti-demagnetization ability of the motor is enhanced. That is, the number of the turns per slot of the winding1026is related to the number of the stator slots1024, and the processing cost of the motor is also related to the utilization rate of the permanent magnet1044, and the utilization rate of the permanent magnet1044is related to the length of the permanent magnet in its own magnetization direction and the distance between the stator core and the rotor core. Therefore, the present application reduces the strength of the demagnetization reverse magnetic field generated by energizing the motor100by reasonably setting the relationship between the distance between the stator core1022and the rotor core1042, the number of the stator slots1024, and the length of the permanent magnet1044in its own magnetization direction, and ensures the anti-demagnetization ability of the motor100and the utilization rate of the permanent magnet1044in the case where the intrinsic coercivity of the permanent magnet1044is reduced, which is conducive to reducing the manufacturing cost of the motor100and improving the cost performance of the motor100, and is suitable for promotion and application.

Further, in one aspect, the stator core1022is provided around the outer circumference of the rotor core1042, i.e., the stator assembly102is located on the outer side of the rotor assembly104. In another aspect, the rotor core1042is provided around the outer circumference of the stator core1022, i.e., the rotor assembly104is located on the outer side of the stator assembly102. The arrangement of the stator core1022and the rotor core1042at different positions can meet the requirements of different types of motors100, so that for different types of motors100, by limiting the distance between the stator core1022and the rotor core1042, the length of the permanent magnet1044in its own magnetization direction, and the number of the stator slots1024in a section perpendicular to the axis of the rotor core1042, the strength of the demagnetization reverse magnetic field generated by energizing the motor100can be reduced, thereby enhancing the anti-demagnetization ability of the motor100, improving the performance of the motor100, and enabling the motor100to meet the requirements for compressor use. [0057] As shown inFIGS.1-3, according to another embodiment of the present application, the motor100comprises a stator assembly102and a rotor assembly104. The stator assembly102comprises a stator core1022provided with a stator slot1024, and the rotor assembly104comprises a rotor core1042and a permanent magnet1044. Further, the number of the stator slots1024is Q, the intrinsic coercivity of the permanent magnet1044is Hcj kA/m, Hcj being less than or equal to 1800 kA/m, the distance between the stator core1022and the rotor core1042is δ mm, and the length of the permanent magnet1044in its own magnetization direction is h mm, the value of h satisfying: 80×(45−Q)/Hcj≤h≤1.3+δ.

In this embodiment, as shown inFIG.3, it is further limited that the numerical range of the length h mm of the permanent magnet1044in its own magnetization direction is: 80×(45−Q)/Hcj≤h≤1.3+δ. By reasonably setting the relationship between h and Q, Hcj, δ, it is beneficial to further reducing the strength of the demagnetization reverse magnetic field generated by energizing the motor100on the basis of improving the utilization rate of the permanent magnet1044of the motor100, and improving the anti-demagnetization ability of the motor100, so that while the manufacturing cost of the motor100is reduced by improving the utilization rate of the permanent magnet1044and reducing the mass percentage of heavy rare earth elements in the permanent magnet1044, the anti-demagnetization ability of the motor100can still meet the requirement of demagnetization resistance for the operation of the compressor, thereby improving the cost performance of the motor100.

Further, the stator core1022is provided with stator slots1024and stator protruding teeth1028, and any stator slot1024is arranged between two adjacent stator protruding teeth1028. The stator assembly102further comprises a coil, the coil is located in the stator slot1024across the stator protruding teeth1028to form the winding1026, and the number of the turns of the winding1026refers to the number of turns of the coil around the stator protruding teeth1028.

Further, the number Q of the stator slots1024ranges from 12 to 36; and/or the distance δ between the stator core1022and the rotor core1042ranges from 0.3 to 0.5 mm; and/or the remanence Br of the permanent magnet ranges from 1.28 T to 1.45 T.

In this embodiment, the numerical ranges of the number Q of the stator slots1024, the distance δ between the stator core1022and the rotor core1042, and the remanence Br of the permanent magnet1044are limited respectively. For example, in one aspect, the number of the stator slots1024is 12≤Q≤36. By reasonably setting the number of the stator slots1024, it is conducive to reducing the number of the turns of the winding1026in each stator slot1024, thereby reducing the strength of the demagnetization reverse magnetic field generated by energizing the motor100and increasing the anti-demagnetization ability of the motor100. The number of the stator slots1024can be 9, 12, 18, 24 or 36.

In another aspect, the distance between the stator core1022and the rotor core1042is 0.3 mm≤δ≤0.5 mm. By reasonably setting the distance between the stator core1022and the rotor core1042, it is conducive to reducing the usage of the permanent magnet1044in the motor100while ensuring the relatively high utilization rate of the permanent magnet1044, thereby reducing the manufacturing cost of the motor and improving the cost performance of the motor, while ensuring the relatively high anti-demagnetization ability of the motor100. For example, in a section perpendicular to the axis of the rotor core1042, the distance δ between the stator core1022and the rotor core1042(i.e., the air gap between the stator assembly and the rotor assembly) is 0.3 mm, 0.4 mm or 0.5 mm.

The remanence of the permanent magnet1044is 1.28 T≤Br≤1.45 T. Remanence refers to a surface field retained by the permanent magnet after magnetization to technical saturation and removal of the external magnetic field, and Br is the residual magnetic induction strength. By reasonably setting the remanence, under the same magnetic load, the larger the value of the remanence Br is, the smaller the usage of the permanent magnet is, thus reducing the manufacturing cost of the motor. Moreover, by reasonably setting the remanence, it is conducive to reducing iron loss, thus improving the efficiency of the motor. The remanence of the permanent magnet can be 1.28 T, 1.32 T or 1.45 T, T being the unit Tesla.

As shown inFIGS.1-3, according to another exemplary embodiment the mass percentage of dysprosium and/or terbium in the permanent magnet ranges from 0 to 0.5%, or the mass percentage of heavy rare earth elements in the permanent magnet ranges from 0 to 0.5%.

In this embodiment, dysprosium and terbium are heavy rare earth elements, which are national strategic resources, and the mass percentage of heavy rare earth elements in the permanent magnet1044is positively correlated with the magnitude of the intrinsic coercivity Hcj of the permanent magnet1044. Therefore, on the one hand, by limiting the range of the mass percentage of dysprosium and/or terbium in the permanent magnet1044to 0 to 0.5%, it is beneficial to reducing the use of dysprosium and/or terbium while ensuring a good anti-demagnetization ability of the motor100, which is therefore beneficial to reducing the manufacturing cost of the motor100and improving the cost performance of the motor100. On the other hand, by limiting the range of the mass percentage of heavy rare earth elements in the permanent magnet1044to 0 to 0.5%, it is beneficial to reducing the use of heavy rare earth elements while ensuring a good anti-demagnetization ability of the motor100, which is therefore beneficial to reducing the manufacturing cost of the motor100and improving the cost performance of the motor100.

For example, the mass percentage of dysprosium and/or terbium in the permanent magnet1044is 0. In one aspect, the mass percentage of dysprosium in the permanent magnet1044is 0, i.e., the permanent magnet1044does not contain the heavy rare earth element dysprosium, which reduces the consumption of the heavy rare earth element dysprosium by the permanent magnet1044and is conducive to energy conservation. In another aspect, the mass percentage of terbium in the permanent magnet1044is 0, i.e., the permanent magnet1044does not contain the heavy rare earth element terbium, which reduces the consumption of the heavy rare earth element terbium by the permanent magnet1044and is conducive to energy conservation. In a further aspect, the sum of the mass percentages of dysprosium and terbium in the permanent magnet1044is 0, i.e., the permanent magnet1044does not contain the heavy rare earth elements dysprosium and terbium, which reduces the consumption of the heavy rare earth elements dysprosium and terbium by the permanent magnet1044, is conducive to the sustainable exploitation of resources and energy conservation, and is conducive to reducing the manufacturing cost of the motor100and suitable for promotion and application.

It can be understood that the mass percentage of dysprosium and/or terbium in the permanent magnet1044may also be other values, for example, the mass percentage of dysprosium and/or terbium in the permanent magnet1044is 0.005%, 0.01%, 0.025%, etc.

For example, the mass percentage of heavy rare earth elements in the permanent magnet1044is 0, i.e., the permanent magnet1044does not contain heavy rare earth elements, which reduces the consumption of strategic resources, is conducive to the sustainable development of resources, reduces the manufacturing cost of the motor100and is suitable for promotion and application. It can be understood that the mass percentage of heavy rare earth elements in the permanent magnet1044may also be other values, for example, the mass percentage of heavy rare earth elements in the permanent magnet1044is 0.005%, 0.01%, 0.025%, etc. The heavy rare earth elements may also include other elements that can be components of the permanent magnet1044.

Further, the permanent magnet1044is a neodymium iron boron permanent magnet, and the neodymium iron boron permanent magnet has excellent magnetic properties and can meet the requirements for use in the motor100. It can be understood that the permanent magnet1044may also be other permanent magnets1044that meet the requirements.

As shown inFIGS.1-3, according to another exemplary embodiment, the motor100further comprises: a plurality of punching sheets (not shown in the figures). The stator core1022can be formed by stacking the punching sheets; alternatively or additionally, the rotor core1042can be formed by stacking the punching sheets (not shown in the figures).

For example, the motor100further comprises punching sheets. In one aspect, the stator core1022is formed by stacking the punching sheets; in another aspect, the rotor core1042is formed by stacking the punching sheets. In a further aspect, the stator core1022and the rotor core1042are both formed by stacking the punching sheets. The different formation manner of the stator core1022or the rotor core1042can meet the requirement of different processing processes of the stator assembly102and the rotor assembly104, leading to a wide scope of application.

For example, the stator core1022and the rotor core1042are both formed by stacking the punching sheets. In one aspect, the punching sheets stacked into the stator core1022are the same as the punching sheets stacked into the rotor core1042, which is conducive to the mass production of the punching sheets and the reduction in the manufacturing cost. In another aspect, the punching sheets stacked into the stator core1022are different from the punching sheets stacked into the rotor core1042, which is conducive to selection of proper punching sheets according to the performance requirement of the motor so as to form the rotor core1042and the stator core1022, thus ensuring good performance of the motor100. Further, the form of stacking the punching sheets achieves the effect of magnetic conductivity of the iron core, can fix the winding1026, and can effectively dissipate heat from the motor100, so that the motor100runs more stably.

Further, the punching sheet is made of a soft magnetic material; and/or the thickness of the punching sheet is 0.2 mm to 0.35 mm.

For example, in one aspect, the soft magnetic material can achieve a relatively large magnetization strength with a relatively small external magnetic field. Selecting the soft magnetic material as the raw material for the punching sheet enables the punching sheet to have a high magnetic conductivity, and the soft magnetic material can be magnetized easily and demagnetized easily, which is conducive to reducing the loss of the stator core1022and/or the rotor core1042, i.e., reducing the iron loss of the motor100, and therefore is conducive to improving the performance of the motor100. In one aspect, the thickness of the punching sheet is limited to be within a range of 0.2 mm to 0.35 mm. The reasonable setting of the thickness of the punching sheet is conducive to effectively reducing iron loss and improving magnetic conductivity, while ensuring good mechanical strength of the stator core1022and/or the rotor core1042, and the reasonable range setting can also meet the working requirements of the motors100of different power.

Further, the rotor core1042is provided with a mounting groove1046, and the permanent magnet1044is arranged in the mounting groove1046. The mounting groove1046is a V-shaped groove, a U-shaped groove, a W-shaped groove, a flat groove or an I-shaped groove.

For example, the mounting groove1046is arranged to have a variety of different structures, such as a V-shaped groove, a U-shaped groove, a W-shaped groove, a flat groove or an I-shaped groove, which can correspondingly realize the mounting of the permanent magnets1044of different structures therein, making the manufacturing process of the motor100more flexible, with more options, and can meet a variety of different application scenarios and expand the scope of use of the product.

An embodiment according to the second aspect of the present application provides a compressor, comprising: a casing, and the motor100in any one of the above embodiments, the motor100being arranged within the casing.

In this embodiment, the compressor comprises the motor100in any of the above embodiments, and therefore has all the beneficial effects of the motor100, which will not be repeated here.

For example, by using a permanent magnet1044that does not contain dysprosium and terbium, or a permanent magnet1044in which the mass percentage of other heavy rare earth elements such as dysprosium and terbium is significantly reduced in the motor100, the consumption of heavy rare earth elements, which are national strategic resources, is reduced and the manufacturing cost of the motor100is significantly reduced. And by setting the length h of the permanent magnet1044in its own magnetization direction, the number Q of the stator slots1024, and the distance δ between the stator core1022and the rotor core1042, the strength of the demagnetization reverse magnetic field generated by energizing the motor is reduced, while the utilization rate of the permanent magnet1044of the motor100is improved, so that the anti-demagnetization ability of the motor100can meet the requirement of demagnetization resistance for the operation of the compressor.

An embodiment according to the third aspect of the present application provides a refrigeration device, comprising: the motor100in any of the above embodiments, or the compressor in any of the above embodiments.

In this embodiment, the refrigeration device comprises the motor100in any of the above embodiments or the compressor in any of the above embodiments, and therefore has all the beneficial effects of the motor100or the compressor, which will not be repeated here.

Further, the refrigeration device also comprises a pipeline communicating with the compressor, and a refrigerant passes through the circulation loop formed by the pipeline and the compressor to achieve heat exchange and refrigeration. For example, the refrigeration device is an air conditioner, and the air conditioner is a household variable-frequency air conditioner.

Exemplary Example

As shown inFIG.1andFIG.2, the motor100provided according to an embodiment of the present application comprises a stator assembly102and a rotor assembly104. An air gap is provided between the rotor assembly104and the stator assembly102, as shown inFIG.3, the width of the air gap is the distance δ between the stator core and the rotor core in a section perpendicular to the axis of the rotor core. The rotor assembly104is disposed opposite the stator assembly102and is rotatable relative to the stator assembly102. The rotor assembly104is disposed coaxially within the stator assembly102.

The stator assembly102comprises a stator core1022and a winding1026. The stator core1022is provided with a stator slot1024, and the winding1026is arranged in the stator slot1024.

The rotor assembly104comprises a rotor core1042and a permanent magnet, the rotor core1042is provided with a mounting groove1046, and the permanent magnet1044is arranged in the mounting groove1046. The permanent magnet is a neodymium iron boron magnet. For example, the neodymium iron boron magnet does not contain heavy rare earth elements dysprosium and terbium, and the intrinsic coercivity of the permanent magnet at 20° C. is Hcj, Hcj≤1800 kA/m.

It is limited that the number of the stator slots1024is Q, the width of the air gap is δ mm, and the thickness of the permanent magnet1044in the section perpendicular to the axis of the rotor core1042is h mm, i.e., the length of the permanent magnet1044in the magnetization direction is h mm. It is found through studies that when the value of h satisfies 80×(43−Q)/Hcj≤h≤1.6+δ, the utilization rate of the permanent magnet1044of the motor100is relatively high, the cost of the motor100is low, and the anti-demagnetization ability meets the requirement of demagnetization resistance for the operation of the compressor, which improves the cost performance of the motor.

For example, in the B-H curve of the permanent magnet shown inFIG.4, when the permanent magnet1044does not have an externally applied magnetic field, the working point of the permanent magnet1044is at the position of point P. When a reverse magnetic field is applied, the working point moves down along the B-H curve to the position of point W; and when the reverse magnetic field is removed, the working point returns along the return line of point W. When point W is located above the inflection point D of the B-H curve, the return line coincides with the B-H curve (the Br1-D solid line shown inFIG.4). When point W exceeds the inflection point D, the return line of point W is parallel to the straight line segment of the B-H curve, and the return line at this time is the Br2-W dotted line shown inFIG.4, producing irreversible demagnetization.

As can be seen, there are three factors that affect the anti-demagnetization ability of the motor100, i.e., the position of the working point of the permanent magnet1044, the magnitude of the absolute value of the intrinsic coercivity Hcj of the permanent magnet1044, and the strength of the reverse magnetic field. Hcj determines the magnitude of the value of the inflection point D. The larger the absolute value of Hcj is, the larger the Hd value of the inflection point D is and the stronger the anti-demagnetization ability is. The smaller the absolute value of Hcj is, the smaller the Hd value of the inflection point D is and the weaker the anti-demagnetization ability is. The higher the position of the working point of the permanent magnet1044is, the stronger the anti-demagnetization ability is. The strength of the reverse magnetic field determines the distance by which the working point P moves down to W. When the working point position P remains unchanged, the reverse magnetic field is relatively strong, and the lower point W is, the weaker the anti-demagnetization ability is.

Further, the components of the permanent magnet1044in the present application do not contain heavy rare earth elements such as dysprosium and terbium, i.e., the mass percentage of heavy rare earth elements, or dysprosium and terbium in the permanent magnet is 0. At 20° C., the intrinsic coercivity (Hcj≤1800 kA/m) of the permanent magnet is significantly smaller than the coercivity (Hcj≥1830 kA/m) of the permanent magnet containing dysprosium and terbium. The B-H curves of different permanent magnets are shown inFIG.5. In the field of compressors, if the permanent magnets1044free of dysprosium and terbium are directly applied to the prior art (e.g., a slot-pole match of 9 slots and 6 poles), the demagnetization ability of the motors100decreases by 40% or more, and the demagnetization ability of the motors cannot meet the requirement.

For the cost of the motor, improving the utilization rate of the permanent magnet1044can reduce the usage of the permanent magnet1044and thereby reduce the cost of the motor100. The utilization rate of the permanent magnet1044can reach its maximum when the working point of the permanent magnet1044is at a position with the maximum magnetic energy product of the permanent magnet1044. In other words, the closer the working point of the permanent magnet1044is to the position with the maximum magnetic energy product, the higher the utilization rate of the permanent magnet1044is. The position with the maximum magnetic energy product of the permanent magnet1044is generally the midpoint of the straight section of the demagnetization curve of the permanent magnet1044. Studies show that, the larger the length of the permanent magnet1044in the magnetization direction (i.e., the length h of the permanent magnet in its own magnetization direction) is, the higher the working point of the permanent magnet1044is, and in the upper half of the B-H curve, the higher the working point is and the further the working point is from the point with the maximum magnetic energy product, the lower the utilization rate of the permanent magnet1044is. In another aspect, the air gap width δ between the stator core1022and the rotor core1042of the motor also affects the usage of the permanent magnet1044. The smaller the air gap width δ is, the lower the usage of the permanent magnet1044is. When the width of the permanent magnet1044is certain, the length h of the permanent magnet1044in its own magnetization direction is smaller.

In other words, the larger the h of the permanent magnet is, the higher the working point of the permanent magnet1044is, but the lower the utilization rate of the permanent magnet1044is; conversely, the smaller the h of the magnet is, the lower the working point of the permanent magnet1044is, the higher the utilization rate of the permanent magnet1044is, but the lower the working point of the permanent magnet1044is, the poorer the anti-demagnetization ability is.

For the above reasons, this embodiment enhances the anti-demagnetization ability of the motor by reducing the strength of the reverse magnetic field generated by energizing the winding of the motor100to demagnetize the permanent magnet. Reducing the strength of the reverse magnetic field is mainly to reduce the number of the turns of the winding1026in each stator slot1024. It is known from electro mechanics that the number of the series turns of the winding per phase is equal to the number of the turns per slot/2 (double-layer winding) multiplied by the number Q of the stator slots and then divided by the number m of the phases. As can be seen, increasing the number Q of the stator slots1024can reduce the number of the turns per slot of the winding1026, and when the number of the turns per slot is reduced, the strength of the reverse magnetic field is reduced, and the anti-demagnetization ability of the motor is enhanced. Then when the length h of the permanent magnet in its own magnetization direction satisfies 80×(43−Q)/Hcj≤h≤1.6+δ, the motor100has the highest utilization rate of the permanent magnet1044, the cost of the motor100is low, and the anti-demagnetization ability is high.

Further, h, Q, δ and Hcj can be designed according to the following relation: 80×(45−Q)/Hcj≤h≤1.3+δ.

Further, the number Q of the stator slots1024is ≥12, and the air gap width δ≤0.5 mm.

Further, the remanence Br of the permanent magnet1044is ≥1.28 T.

Further, the mounting groove1046of the magnet1044may have various forms in shape and distribution position. The mounting groove1046of the permanent magnet1044is a V-shaped groove, a U-shaped groove, a W-shaped groove, a flat groove or an I-shaped groove.

Further, the stator core1022and the rotor core1042are made of soft magnetic material sheets, the soft magnetic material sheet is a silicon steel sheet, and the thickness of the soft magnetic material sheet is 0.2 mm-0.35 mm.

In description of the present application, the term “a plurality of” means two or more, unless otherwise explicitly defined. The orientation or position relationships indicated by the terms “upper”, “lower” and the like are the orientation or position relationships based on what is shown in the drawings, are merely for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or unit referred to must have a particular orientation and is constructed and operated in a specific orientation, and thus cannot be understood as the limitation of the present application. The terms “connection”, “mounting”, “fixing” and the like should all be understood in a broad sense, for example, “connection” may be a fixed connection, and may also be a removable connection, or an integral connection; may refer to direct connection and may also refer to indirect connection through an intermediary. A person of ordinary skills in the art could understand the specific meaning of the terms in the present application according to specific situations.

In the description of the present application, the descriptions of the terms “one embodiment”, “some embodiments” and “specific embodiments” and the like mean that specific features, structures, materials or characteristics described in conjunction with the embodiment(s) or example(s) are included in at least one embodiment or example of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the particular features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

The descriptions above are only preferred embodiments of the present application, which are not used to limit the present application. For a person skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements etc. within the spirit and principle of the present application shall all be included in the protection scope of the present application.