Electric machine and compressor

Abstract

The application provides a motor and compressor, the motor comprises a plurality of pairs of magnetic pole pairs, a stator and a rotor, the stator comprises a yoke part and a central hole in a ring shape, a plurality of tooth parts towards the center are arranged between the inner side of the yoke part and the central hole. The rotor is sleeved in the central hole, and a plurality of magnet grooves are arranged on the rotor. The outer diameter D1 of the stator and the outer diameter D2 of the rotor satisfy: 1.85 >= D1 / D2 >= 1.74; the width L1 of the tooth part and the thickness L2 of the yoke part satisfy: 0.82 >= L1 / L2 >= 0.73; the side length L3 of the magnet groove, the thickness L4 of the magnet groove and the number P of the magnetic pole pairs satisfy: 20.9 >= (L3 / L4) x P >= 19.1. In the motor of the application, the outer diameter D1 of the stator and the outer diameter D2 of the rotor, the width L1 of the tooth part and the thickness L2 of the yoke part, the side length L3 of the magnet groove, the thickness L4 of the magnet groove and the number P of the magnetic pole pairs are set by using the above reasonable ratio, the rotational inertia of the rotor can be improved, the counter electromotive force of the motor can be changed, and the efficiency of the motor can be obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressor, in particular to a motor and a compressor. BACKGROUND

[0002] Energy saving and environmental protection are two major themes of the refrigeration industry. In view of the gradual increase of energy saving requirements, the energy efficiency level requirements of refrigeration equipment are further improved. Under the premise of ensuring reliability, in order to improve the efficiency of the compressor, the working parts of the compressor need to be optimized, and the size is set in the best interval, so as to achieve the optimal efficiency of the compressor.

[0003] The motor is a power output component in the compressor, and is also an important component affecting the efficiency of the compressor. When designing the motor, the size of the motor is optimized, and the size is set in the best interval, which can significantly improve the efficiency of the compressor. In the motor of the compressor, the magnetic field generated by the stator interacts with the magnetic field generated by the rotor, so that the rotor rotates. When designing the motor rotor and the stator, the inner / outer diameter size, ratio, magnet slot shape, size, winding method, magnet material, grade, form and amount, etc. are comprehensively considered to achieve the best performance requirement. Therefore, the person skilled in the art needs to optimize the parameters of the motor components.

[0004] In summary, how to optimize the parameters of the motor components to improve the efficiency of the motor is the direction that needs to be studied in the field of compressor. SUMMARY

[0005] The purpose of the present application is to provide a motor with higher efficiency.

[0006] In order to achieve the above purpose, the present application provides a motor, comprising:

[0007] a plurality of pairs of magnetic poles;

[0008] a stator comprising a yoke portion, a tooth portion and a central hole;

[0009] a rotor arranged in the central hole, the rotor being provided with a plurality of V-shaped magnet grooves, the V-shaped magnet grooves being composed of two opposite one-shaped side walls arranged at an angle;

[0010] The outer diameter D1 of the stator and the outer diameter D2 of the rotor satisfy the following relationship:

[0011]

[0012] The width L1 of the tooth portion and the thickness L2 of the yoke portion satisfy the following relationship:

[0013]

[0014] The length L3 of the side wall, the width L4 of the side wall and the number P of the pole pairs satisfy the following relationship:

[0015]

[0016] Optionally, the number of the pole pairs is 2 to 6 pairs.

[0017] Optionally, the outer diameter D1 of the stator is 90mm to 120mm, and the outer diameter D2 of the rotor is 55mm to 65mm.

[0018] Optionally, the width L1 of the tooth part is 6.4mm to 7.1mm, and the thickness L2 of the yoke part is 8.4mm to 9.4mm.

[0019] Optionally, the length L3 of the side wall is 6.92mm to 10.92mm, and the width L4 of the side wall is 1.55mm to 1.95mm.

[0020] The application further provides a compressor comprising the motor described above, the inner periphery of the yoke part of the stator is provided with a plurality of tooth parts, the recess formed between adjacent tooth parts is a stator slot, the number of the stator slots is 12, and the number P of the pole pairs is 4.

[0021] Optionally, the outer diameter D1 of the stator is 107.15mm, the outer diameter D2 of the rotor is 57.93mm, the width L1 of the tooth part is 6.9mm, the thickness L2 of the yoke part is 9.35mm, the length L3 of the side wall of the magnet slot is 8.92mm, and the width L4 of the side wall of the magnet slot is 1.75mm.

[0022] Optionally, the outer diameter D1 of the stator is 107.15mm, the outer diameter D2 of the rotor is 57.93mm, the width L1 of the tooth part is 6.9mm, the thickness L2 of the yoke part is 8.48mm, the length L3 of the side wall is 8.92mm, and the width L4 of the side wall is 1.75mm.

[0023] Optionally, the outer periphery of the yoke part of the stator is provided with a plurality of pairs of cutting edges, each pair of the cutting edges is symmetric to the center of the stator lamination, both ends of the cutting edge are provided with a first recess, and at least one second recess is further provided in the middle of the cutting edge.

[0024] Optionally, the outer periphery of the yoke part is provided with 3 pairs of cutting edges.

[0025] In the motor of the present application, the outer diameter D1 of the stator and the outer diameter D2 of the rotor, the width L1 of the tooth portion and the thickness L2 of the yoke portion, the length L3 of the magnet slot side wall, the width L4 of the magnet slot side wall and the number P of the pole pairs are set with the above reasonable ratio, which can improve the rotational inertia of the rotor, change the counter electromotive force of the motor and obviously improve the efficiency of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Fig. 1 is a structural schematic diagram of a compressor in an embodiment of the present application.

[0027] Figure 2 Fig. 2 is a structural schematic diagram of a stator in an embodiment of the present application.

[0028] Figure 3 Fig. 3 is a partial view of the stator in an embodiment of the present application.

[0029] Figure 4 Fig. 4 is a partial view of a rotor in an embodiment of the present application.

[0030] In the drawings, the reference signs are as follows:

[0031] 100 - pump shell

[0032] 200 - stator; 210 - yoke portion; 220 - tooth portion; 230 - undercut; first recess 2301; second recess 2302

[0033] 300 - rotor; 310 - magnet slot

[0034] 400 - rotating shaft

[0035] D1 - outer diameter of stator; D2 - outer diameter of rotor; L1 - width of tooth portion; L2 - thickness of yoke portion; L3 - length of side wall; L4 - width of side wall; P - number of pole pairs DETAILED DESCRIPTION

[0036] The specific embodiments of the present application will be described in more detail below with reference to the accompanying drawings. The advantages and features of the present application will be more apparent from the following description. It should be noted that the drawings are very simplified and are not drawn to scale, and are only used to facilitate and clarify the purpose of assisting the description of the embodiments of the present application.

[0037] Figure 1 Fig. 1 is a structural schematic diagram of a compressor in an embodiment of the present application. Figure 2 Fig. 2 is a structural schematic diagram of a stator in an embodiment of the present application. As shown in Fig. 2, the stator 200 comprises a yoke portion 210 and a tooth portion 220. Figure 1 and Figure 2As shown, the compressor comprises a pump shell 100 and a motor installed in the pump shell 100, the motor comprising a stator 200, a rotor 300 and a rotating shaft 400. The motor is a single-phase synchronous motor, also known as a permanent magnet motor, whose rotor 300 rotates at the same speed as the rotating magnetic field of the stator 200. The relationship between the rotor 300 speed and the number of magnetic pole pairs P and the power frequency F is as follows:

[0038]

[0039] From the above formula, it can be seen that the speed N is determined by the power frequency F. Therefore, when the power frequency is constant, that is, in the case of constant output power, the smaller the number of magnetic pole pairs P of the motor, the greater the speed of the motor, but the smaller the torque of the motor.

[0040] The stator 200 is fixedly connected to the inner wall of the pump shell 100. The stator 200 of the motor is basically the same as that of a common induction motor, and uses a lamination structure to reduce the iron loss during motor operation. The rotor 300 is also formed by lamination and stacking. The lamination forming the stator 200 is also called stator 200 punching, and the lamination forming the rotor 300 is also called rotor 300 punching.

[0041] The stator 200 is arranged in cooperation with the rotor 300. The rotor 300 of the motor is provided with excitation by a permanent magnet. The excitation provided by the permanent magnet makes the motor structure relatively simple, reduces the processing and assembly cost, and saves the current collector ring and brush which are prone to problems, thereby improving the reliability of the motor operation. In addition, there is no excitation current and no excitation loss, thereby improving the efficiency and power density of the motor.

[0042] In order to place the permanent magnet, a plurality of magnet grooves 310 need to be formed on the rotor 300. In this embodiment, the magnet grooves 310 are arranged in a V shape. The same magnet groove 310 is provided with a permanent magnet with the same magnetic pole, and the adjacent magnet groove 310 is provided with a permanent magnet with opposite magnetic poles. The permanent magnet is usually a magnet. The V-shaped magnet groove is composed of two opposite inclined side walls of the one-shaped side wall. The midpoint of the V-shaped magnet groove 310 and the center of the rotor 300 form an axis line, and the V-shaped magnet groove 310 is symmetrical with respect to the axis line.

[0043] The rotor 300 is sleeved on the rotating shaft 400. The rotating shaft 400 is arranged along the length direction of the pump shell 100. The inner wall of the rotor 300 is in interference fit with the outer wall of the rotating shaft 400.

[0044] Generally, the rotating shaft 400 is a crankshaft, and the two ends of the crankshaft are a long end and an eccentric end. The crankshaft penetrates the through hole of the upper cylinder cover 500, and the middle part of the crankshaft is sleeved with the upper cylinder cover 500. The eccentric end of the crankshaft is located in the cylinder, and the middle part of the cylinder is provided with a piston. The piston is movably arranged in the inside of the cylinder, and the piston is sleeved with the eccentric end of the crankshaft. Thus, the rotation of the crankshaft drives the eccentric end, and the eccentric end further drives the piston to move repeatedly.

[0045] The stator 200 further comprises a main winding coil (main winding), a sub-winding coil (sub-winding) and a stator 200 slot, wherein the main winding coil and the sub-winding coil are arranged in different stator 200 slots, respectively.

[0046] When a single-phase sinusoidal current passes through the main winding coil and the sub-winding coil of the stator 200, an alternating magnetic field is generated. The strength and direction of the magnetic field changes sinusoidally with time, but is fixed in space orientation, so it is also called an alternating pulsating magnetic field. The alternating pulsating magnetic field can be decomposed into two rotating magnetic fields with the same speed and opposite rotating directions. When the rotor 300 is stationary, the two rotating magnetic fields generate two torques with equal size and opposite directions in the rotor 300, so that the resultant torque is zero, and the rotor 300 cannot rotate. When we rotate the motor in a certain direction (such as clockwise) by external force, the cutting magnetic field lines between the rotor 300 and the clockwise rotating magnetic field move smaller, and the cutting magnetic field lines between the rotor 300 and the counterclockwise rotating magnetic field move larger. In this way, the balance is broken, and the total electromagnetic torque generated by the rotor 300 will no longer be zero, and the rotor 300 will rotate in the pushing direction. The sub-winding is also called the starting winding. The sub-winding is connected in series with a capacitor, so that the voltage of the sub-winding lags behind the current by several phase angles, for example, but not limited to, 90 degrees. In this way, the main winding and the sub-winding obtain different magnetic fields, forming a rotating magnetic field, and then driving the rotor 300 to rotate.

[0047] According to the electromagnetic law, when the magnetic field changes, the nearby conductor will generate an induced electromotive force, whose direction meets the Faraday's law and the Lenz's law, and is opposite to the voltage applied to the winding coil. This voltage is called back electromotive force. The rotation of the rotor of the motor cuts the magnetic field lines to generate an induced electromotive force, whose direction is opposite to the applied voltage, so it is called back electromotive force of the motor.

[0048] The motor is a power output component in the compressor, and is also an important component affecting the efficiency of the compressor. When designing the motor, the size of the motor is optimized to be in the best interval, which can significantly improve the efficiency of the compressor. Based on this, the present application provides a motor.

[0049] Figure 3 It is a partial view of the stator provided in the embodiment. Figure 4A partial view of a rotor provided in the embodiment. As shown in Figure 3 and Figure 4 The motor comprises a plurality of pairs of magnetic pole pairs, a stator and a rotor.

[0050] The stator 200 comprises a yoke portion 210, a tooth portion 220 and a central hole. The yoke portion is in the form of a ring, and the tooth portion is arranged at the inner periphery of the yoke portion 210 and extends to the central hole in the radial direction of the stator 200.

[0051] The rotor 300 is arranged in the central hole, and a plurality of V-shaped magnet grooves 310 are arranged on the rotor 300. The V-shaped magnet grooves 310 are formed by two opposite and obliquely arranged linear sidewalls.

[0052] The outer diameter D1 of the stator and the outer diameter D2 of the rotor satisfy the following relationship:

[0053]

[0054] The width L1 of the tooth portion and the thickness L2 of the yoke portion satisfy the following relationship:

[0055]

[0056] The length L3 of the sidewall, the width L4 of the sidewall and the number P of the magnetic pole pairs satisfy the following relationship:

[0057]

[0058] In the motor of the present application, the outer diameter D1 of the stator and the outer diameter D2 of the rotor, the width L1 of the tooth portion and the thickness L2 of the yoke portion, the length L3 of the magnet groove sidewall, the width L4 of the magnet groove sidewall and the number P of the magnetic pole pairs are set using the above reasonable ratios, which can significantly improve the efficiency of the motor.

[0059] In detail, when the ratio of the outer diameter D1 of the stator and the outer diameter D2 of the rotor is small, the outer diameter D2 of the rotor is small, at this time, the rotational inertia of the rotor 300 is low, the low-speed torque ripple consumes a large amount of energy, causing the performance of the motor to decrease. When the ratio of the outer diameter D1 of the stator 200 and the outer diameter D2 of the rotor 300 is large, the cross-sectional area of the stator 200 is too small, resulting in excessive motor iron loss, thereby affecting the efficiency of the motor.

[0060] Therefore, in order to compensate for the energy loss caused by the low-speed torque ripple of the rotor 300, the appropriate rotational inertia corresponding to the outer diameter D2 of the rotor 300 should be selected to compensate for this part of the energy loss, and the efficiency of the motor should be considered.

[0061] The applicant obtains the conditions of the moment of inertia of the rotor 300 and the motor efficiency when the outer diameter D1 of the stator 200 and the outer diameter D2 of the rotor 300 are in different ratios through simulation analysis, as shown in Table 1.

[0062] D1 D2 Moment of inertia Motor efficiency Contrast size 107.15 54.93 282 92.11％ Proposal size 107.15 57.93 353 92.37％

[0063] Table 1

[0064] It can be seen that the increase of the moment of inertia of the rotor 300 has obvious effect on the improvement of the motor performance.

[0065] It should be understood that the stator slots are formed between the adjacent tooth portions 220 in the stator 200, and therefore, for the stator 200 in the above-mentioned size, the dimensions of the width L1 of the tooth portion and the thickness L2 of the yoke portion can be reasonably set to change the area of the stator slot on the stator 200, so as to adjust the size of the motor coil, and then balance the iron loss of the motor, thereby improving the motor performance.

[0066] The applicant obtains the conditions of the stator slot area of the stator 200 and the motor efficiency when the width L1 of the tooth portion and the thickness L2 of the yoke portion are in different ratios through simulation analysis, as shown in Table 2.

[0067]

[0068]

[0069] Table 2

[0070] Meanwhile, different magnet sizes (the larger the cross-sectional area, the higher the magnet size) can produce different magnetic flux in the V-shaped magnet slot 310 on the rotor 300. Different magnetic flux makes the back electromotive force of the motor different, which has a certain influence on the current of the motor running, thereby improving the copper loss of the motor.

[0071] The V-shaped magnet slot 310 has two side wall grooves, and therefore, the magnet size can be changed by adjusting the length L3 of the side wall of the magnet slot 310 and the width L4 of the side wall of the magnet slot 310. The applicant obtains the conditions of the back electromotive force of the motor and the motor efficiency when the length L3 of the side wall of the magnet slot 310, the width L4 of the side wall of the magnet slot 310 and the number P of the magnetic pole pairs are in different ratios through simulation analysis, as shown in Table 3.

[0072] L3 L4 P Counter electromotive force Motor performance Contrast size 8.89 1.7 4 50.83 91.38％ Proposal size 8.92 1.75 4 52.9 92.37％

[0073] Table 3

[0074] For the motor of the proposed size, the structure of the corresponding stator 200 and rotor 300 can improve the rotational inertia of the rotor 300, adjust the area of the magnet slot 310, improve the back electromotive force, and improve the motor efficiency.

[0075] Optionally, the number of pole pairs of the motor is 2 to 6 pairs. It should be understood that those skilled in the art can select the number P of pole pairs according to their own requirements for the speed and torque of the motor. Preferably, the inner periphery of the yoke portion 210 of the stator 200 is provided with a plurality of tooth portions 220, and the recess formed between adjacent tooth portions 220 is a stator slot. The number of stator slots is 12, and the number P of pole pairs in the embodiment is 4 pairs.

[0076] Optionally, the size of the outer diameter D1 of the stator 200 is 90 mm to 120 mm.

[0077] Optionally, the size of the outer diameter D2 of the rotor 300 is 55 mm to 65 mm.

[0078] Optionally, the size of the width L1 of the tooth portion is 6.4 mm to 7.1 mm.

[0079] Optionally, the size of the thickness L2 of the yoke portion is 8.4 mm to 9.4 mm.

[0080] Optionally, the size of the length L3 of the magnet slot sidewall is 6.92 mm to 10.92 mm.

[0081] Optionally, the size of the width L4 of the magnet slot sidewall is 1.55 mm to 1.95 mm.

[0082] Optionally, the outer periphery of the yoke portion 210 is provided with a plurality of pairs of cut edges 230, each pair of cut edges 230 is symmetrical along the center of the stator, both ends of the cut edge 230 are provided with a first recess 2301, and at least one second recess 2302 is further provided in the middle of the cut edge 230. Preferably, the depth of the second recess 2302 is greater than the depth of the first recess 2301. In the embodiment, the outer periphery of the yoke portion is provided with three pairs of cut edges 230. Reasonably arranging the cut edges can ensure the flow rate of the refrigerant without affecting the electromagnetic field flow of the stator yoke portion 210, and can also reduce the amount of steel plate used during the manufacturing of the stator.

[0083] It should be understood that those skilled in the art can select the sizes of the outer diameter D1 of the stator 200, the outer diameter D2 of the rotor 300, the width L1 of the tooth portion, the thickness L2 of the yoke portion, the length L3 of the magnet slot sidewall, and the width L4 of the magnet slot sidewall according to their own comprehensive considerations of the size of the motor and the efficiency of the motor.

[0084] In summary, the application provides a motor, which comprises a plurality of pairs of magnetic pole pairs, a stator and a rotor. The stator comprises a yoke, a tooth portion and a central hole. The yoke is annular, the tooth portion is arranged at the inner periphery of the yoke and extends to the central hole along the radial direction of the stator. The rotor is arranged in the central hole, and a plurality of V-shaped magnet grooves are arranged on the rotor, wherein the V-shaped magnet grooves are formed by two opposite and obliquely arranged linear sidewalls. The outer diameter D1 of the stator and the outer diameter D2 of the rotor satisfy the following relationship:

[0085]

[0086] The width L1 of the tooth portion and the thickness L2 of the yoke satisfy the following relationship:

[0087]

[0088] The length L3 of the sidewall, the width L4 of the sidewall and the number P of the pairs of magnetic poles satisfy the following relationship:

[0089]

[0090] In the motor of the application, the outer diameter D1 of the stator and the outer diameter D2 of the rotor, the width L1 of the tooth portion and the thickness L2 of the yoke, the length L3 of the sidewall of the magnet groove, the width L4 of the sidewall of the magnet groove and the number P of the pairs of magnetic poles are set according to the above reasonable ratios, so that the rotational inertia of the rotor can be improved, the counter electromotive force of the motor can be changed, and the efficiency of the motor can be obviously improved.

[0091] The above is only the preferred embodiment of the application, and does not limit the application in any way. Any person skilled in the art can make any equivalent replacement, modification or change to the technical solutions and technical contents disclosed in the application without departing from the scope of the technical solutions of the application, and such changes still fall within the protection scope of the application.

Claims

1. An electric machine characterized in that, The motor comprises: a plurality of pairs of magnetic poles; a stator comprising a yoke portion, a tooth portion and a central hole; a rotor arranged in the central hole, the rotor being provided with a plurality of V-shaped magnet grooves, the V-shaped magnet grooves being formed by two opposite one-wall side walls arranged at an angle; the outer diameter D1 of the stator and the outer diameter D2 of the rotor satisfy the following relationship: the width L1 of the tooth portion and the thickness L2 of the yoke portion satisfy the following relationship: the length L3 of the side wall, the width L4 of the side wall and the number P of the pairs of magnetic poles satisfy the following relationship:

2. The electric machine of claim 1, wherein, the number of the pairs of magnetic poles is 2 to 6 pairs.

3. The electric machine of claim 1, wherein, the outer diameter D1 of the stator is 90mm to 120mm, and the outer diameter D2 of the rotor is 55mm to 65mm.

4. The electric machine of claim 1, wherein, the width L1 of the tooth portion is 6.4mm to 7.1mm, and the thickness L2 of the yoke portion is 8.4mm to 9.4mm.

5. The electric machine of claim 1, wherein, the length L3 of the side wall is 6.92mm to 10.92mm, and the width L4 of the side wall is 1.55mm to 1.95mm.

6. A compressor characterized by, The motor comprises the stator as claimed in any one of claims 1 to 5, wherein the inner periphery of the yoke portion of the stator is provided with a plurality of tooth portions, and a groove formed between adjacent tooth portions is a stator groove, the number of the stator grooves is 12, and the number P of the pairs of magnetic poles is 4.

7. The compressor of claim 6, wherein, the outer diameter D1 of the stator is 107.15mm, the outer diameter D2 of the rotor is 57.93mm, the width L1 of the tooth portion is 6.9mm, the thickness L2 of the yoke portion is 9.35mm, the length L3 of the side wall is 8.92mm, and the width L4 of the side wall is 1.75mm.

8. The compressor of claim 6, wherein, the outer diameter D1 of the stator is 107.15mm, the outer diameter D2 of the rotor is 57.93mm, the width L1 of the tooth portion is 6.9mm, the thickness L2 of the yoke portion is 8.48mm, the length L3 of the side wall is 8.92mm, and the width L4 of the side wall is 1.75mm.

9. The compressor of claim 6, wherein, the outer periphery of the yoke portion of the stator is provided with a plurality of pairs of cut edges, each pair of cut edges is symmetric to the center of the stator lamination, both ends of the cut edge are provided with a first recess, and at least one second recess is further provided in the middle of the cut edge.

10. The compressor of claim 9, wherein, the outer periphery of the yoke portion is provided with 3 pairs of cut edges.

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