Motor rotor, motor and DC variable frequency compressor

Abstract

The present invention provides a motor rotor, a motor and a DC variable frequency compressor. Since a V-shaped magnet groove is arranged on the rotor core, the amount of embedded permanent magnets is significantly increased, thereby improving the torque density of the motor, meeting the requirements of high efficiency and miniaturization of the motor, and further improving the performance of the DC variable frequency compressor. At the same time, since the main and auxiliary refrigerant through holes on the rotor core are arranged in accordance with the V-shaped magnet groove and the shaft hole, the requirements of the mechanical strength of the rotor are met, and the problem of a significant increase in the magnetic resistance on the rotor side due to the magnetic field lines of the rotor main pole passing through the refrigerant through hole to form a closed loop can be avoided, thereby increasing the rotor refrigerant flow area as much as possible under the premise of ensuring the performance and reliability of the motor, promoting the circulation of the refrigerant in the compressor, and achieving the purpose of cooling the rotor.

Description

Technical Field

[0001] The present invention relates to the technical field of motors and compressors, and in particular to a motor rotor, a motor and a direct current variable frequency compressor. Background Art

[0002] Compressors are core components of electrical appliances such as air conditioners and refrigerators, and most compressors are driven by electric motors, which consume a lot of energy. With the progress of society and the increasingly severe energy situation, related industries are increasingly committed to launching some energy-saving and consumption-reducing products. In recent years, DC frequency conversion technology has become one of the main technologies in the refrigeration industry, and permanent magnet synchronous motors have also become the first choice for motors used in compressors.

[0003] The permanent magnet synchronous motor used in DC variable frequency compressors consists of a stator and a rotor. The stator is fixed in the compressor, while the rotor in the compressor has a permanent magnet and uses an eccentric shaft design to drive the piston and other parts to compress the refrigerant.

[0004] like Figure 1 As shown, the existing embedded permanent magnet synchronous motor rotor for DC variable frequency compressor generally includes a rotor core 101, a permanent magnet 102 embedded and fixed on the rotor core 101, and a rivet 103 for fixing the rotor core 101 and other parts. The center of the rotor core 101 is provided with a shaft hole 105 for passing the eccentric shaft, and the rotor core 101 is also provided with a plurality of refrigerant through holes 104 arranged along the circumference of the rotor core 101. Among them, the permanent magnet 102 is usually placed orthogonally to the diameter direction of the rotor core 101. This placement method makes the amount of permanent magnet 102 small, and it is difficult to achieve miniaturization and high efficiency of the motor. Summary of the invention

[0005] The object of the present invention is to provide a motor rotor, a motor and a DC variable frequency compressor, which can improve the torque density of the motor, meet the requirements of motor efficiency and miniaturization, and thus improve the performance of the DC variable frequency compressor.

[0006] In order to solve the above problems, the present invention proposes an electric motor rotor, wherein a shaft hole for passing the shaft is arranged at the center of the rotor core of the electric motor rotor, and a magnet groove, a rivet hole, a secondary refrigerant through hole and a main refrigerant through hole are also arranged on the rotor core around the shaft hole. The magnet groove has a V-shaped structure for embedded fixed installation of permanent magnets, and the magnetic poles of the permanent magnets placed in adjacent V-shaped magnet grooves are opposite; the secondary refrigerant through hole is arranged between the V-shaped magnet groove and the shaft hole; the main refrigerant through hole is arranged between adjacent V-shaped magnet grooves.

[0007] Furthermore, a V-shaped permanent magnet is placed in each V-shaped magnet slot, or a linear permanent magnet is placed in each of the two linear slots of each V-shaped magnet slot, and the two linear permanent magnets are placed in a manner such that the magnetic poles have the same polarity.

[0008] Furthermore, the main refrigerant through hole and the auxiliary refrigerant through hole are in the shape of a circle, an ellipse, an arc, an arc with line segments, or a rectangle.

[0009] Further, the line from the center of the shaft hole to the outermost end of the main refrigerant through hole in the radial direction is defined as L1, and the length is d; the line from the center of the shaft hole to the top corner of the V-shaped magnet slot close to the shaft hole is defined as L2, and the angle between the line segment L1 and the line segment L2 is α; the distance from the center of the shaft hole to the line between the two top corners of the V-shaped magnet slot close to the shaft hole is defined as b, and it satisfies:

[0010] Where p is the number of pole pairs of the motor.

[0011] Furthermore, at least one main refrigerant through hole is connected to an oil return through hole on the outer side along the radial direction of the rotor core.

[0012] Furthermore, the shape of the oil return through hole is semicircular, semi-elliptical, arc-shaped, arc-shaped with line segments, or rectangular.

[0013] Furthermore, the length d1 of the oil return hole in the circumferential direction of the rotor core satisfies d1≤d3 / 2, and the length d2 of the oil return hole in the radial direction of the rotor core satisfies d2≥d3 / 16, wherein d3 is the length of the refrigerant hole connected to the oil return hole in the circumferential direction of the rotor core.

[0014] Furthermore, the rotor core includes rotor punchings of the same shape and is stacked by the rotor punchings.

[0015] The present invention also provides an electric motor, comprising a stator and the above-mentioned electric motor rotor, wherein the electric motor rotor is installed in the stator via a rotating shaft for rotation.

[0016] The present invention also provides a DC variable frequency compressor, comprising the above-mentioned motor.

[0017] Compared with the prior art, the motor rotor, motor and DC variable frequency compressor of the present invention have a V-shaped magnet groove on the rotor core, and the amount of embedded permanent magnets is significantly increased, thereby improving the torque density of the motor, meeting the requirements of high efficiency and miniaturization of the motor, and thus improving the performance of the DC variable frequency compressor. At the same time, since the main and auxiliary refrigerant through holes on the rotor core are arranged in accordance with the V-shaped magnet groove and the shaft hole, the requirements of the mechanical strength of the rotor are met, and the problem of a significant increase in the magnetic resistance on the rotor side due to the magnetic field lines of the rotor main pole passing through the refrigerant through hole to form a closed loop can be avoided, thereby increasing the rotor refrigerant flow area as much as possible while ensuring the performance and reliability of the motor, promoting the circulation of the refrigerant in the compressor, and achieving the purpose of cooling the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an existing embedded permanent magnet synchronous motor rotor for a DC variable frequency compressor;

[0019] Figure 2 It is a schematic structural diagram of the motor rotor of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose and features of the present invention more obvious and understandable, the specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings. However, the present invention can be implemented in different forms and should not be limited to the described embodiments.

[0021] Please refer to Figure 2 The present invention provides a motor rotor, wherein the center of the rotor core 2 of the motor rotor is provided with a shaft hole for passing the shaft 1, and the rotor core 2 is also provided with a magnet slot 3 for embedded fixed installation of a permanent magnet 4, a rivet hole for placing a rivet 5, a secondary refrigerant through hole 6 and a main refrigerant through hole 7 on the periphery of the shaft hole, and the permanent magnet 4 can be made of neodymium iron boron or ferrite material, and the rotor core 2 includes rotor punchings of the same shape, which are composed of the rotor punchings by stacking riveting or welding, and connected to other parts of the motor rotor by rivets 5. The motor rotor of the present invention is placed in the corresponding stator through the shaft 1 to rotate to form a motor assembly.

[0022] Wherein, the magnet slot 3 is a V-shaped magnet slot, that is, the magnet slot 3 is in a V-shaped structure, and the magnetic pole polarities of the permanent magnets 4 placed in adjacent V-shaped magnet slots 3 are opposite. One V-shaped permanent magnet 4 can be placed in each V-shaped magnet slot 3, or a linear permanent magnet 4 can be placed in each of the two linear slots of each V-shaped magnet slot 3, and the two linear permanent magnets 4 are placed in a manner with the same magnetic pole polarity. In this embodiment, the edge of the top corner of each V-shaped magnet slot 3 close to the center of the shaft hole is discontinuous, while the edge away from the center of the shaft hole is continuous, and a linear permanent magnet 4 is placed in each of the two linear slots of each V-shaped magnet slot 3, and the two linear permanent magnets 4 have the same magnetic pole polarity, and are respectively against the protruding parts on the edge of the top corner of the V-shaped magnet slot 3 close to the center of the shaft hole, thereby avoiding collision, and the magnetic pole polarities of the permanent magnets 4 placed in adjacent V-shaped magnet slots 3 are opposite. The auxiliary refrigerant through hole 6 is arranged between the corresponding V-shaped magnet slot 3 and the shaft hole; the main refrigerant through hole 7 is arranged between adjacent V-shaped magnet slots 3. Preferably, an auxiliary refrigerant through hole 6 is provided between all V-shaped magnet slots 3 and the shaft hole, a main refrigerant through hole 7 is provided between every two adjacent V-shaped magnet slots 3, and all main refrigerant through holes 7 and auxiliary refrigerant through holes 6 are circular holes, so that all main refrigerant through holes 7 and auxiliary refrigerant through holes 6 are alternately arranged along the circumference of the rotor core 2, thereby increasing the refrigerant flow area. In other embodiments of the present invention, the main refrigerant through hole 7 and the auxiliary refrigerant through hole 6 can be other shapes, such as arc shape, and an auxiliary refrigerant through hole 6 may not be provided between all V-shaped magnet slots 3 and the shaft hole, and a main refrigerant through hole 7 may not be provided between every two adjacent V-shaped magnet slots 3.

[0023] The line from the center of the shaft hole to the outermost end of the main refrigerant through hole 7 in the radial direction is defined as L1, and the length is d; the line from the center of the shaft hole to the top corner of the V-shaped magnet slot 3 close to the shaft hole (i.e., the line from the center of the shaft hole to the end point of the part of the V-shaped magnet slot 3 where the permanent magnet 4 is placed close to the shaft hole) is defined as L2, and the angle between the line segment L1 and the line segment L2 is α; the distance from the center of the shaft hole to the line between the two top corners of the V-shaped magnet slot close to the shaft hole (i.e., the distance from the center of the shaft hole to the center of the line connecting the two end points of the part of the V-shaped magnet slot 3 where the permanent magnet 4 is placed close to the shaft hole) is defined as b, and it satisfies:

[0024] Where p is the number of pole pairs of the motor.

[0025] The motor rotor of the present invention has a V-shaped magnet groove on the rotor core, so the amount of embedded permanent magnets is significantly increased, thereby improving the torque density of the motor and meeting the requirements of high efficiency and miniaturization of the motor. At the same time, the arrangement of the main and auxiliary refrigerant through holes meets the requirements of the mechanical strength of the rotor, and can also avoid the situation where the magnetic field lines of the rotor main pole magnetic field pass through the refrigerant through holes to form a closed loop, resulting in a significant increase in the magnetic resistance on the rotor side, thereby increasing the rotor refrigerant flow area as much as possible while ensuring the performance and reliability of the motor, promoting the circulation of the refrigerant in the compressor, and achieving the purpose of cooling the rotor.

[0026] In addition, at least one main refrigerant through hole 7 on the rotor core 2 is provided with an oil return through hole 8 connected to the main refrigerant through hole 7 on the outer side along the radial direction of the rotor core 2. The shape of the oil return through hole 8 is semicircular, semi-elliptical, arc-shaped, arc-shaped with line segments or rectangular. The length d1 of the oil return through hole 8 in the circumferential direction of the rotor core 2 satisfies d1≤d3 / 2, and the length d2 of the oil return through hole 8 in the radial direction of the rotor core 2 satisfies d2≥d3 / 16, wherein d3 is the length of the refrigerant through hole 7 connected to the oil return through hole 8 in the circumferential direction of the rotor core 2.

[0027] Since an oil return hole 8 connected to the refrigerant hole 7 is provided on the rotor core 2, the refrigeration oil that is partially atomized and dissolved in the refrigerant gas in the refrigerant hole 7 can be thrown to the oil return hole 8 under the action of radial force when the rotor rotates and fall back along the oil return hole 8, reducing the refrigeration oil brought into the upper part of the motor, thereby reducing the oil output rate of the compressor and ensuring the lubricity of the pump body.

[0028] The present invention also provides a motor, comprising a stator and the motor rotor, wherein the motor rotor is installed in the stator for rotation via a rotating shaft 1. The motor adopts the motor rotor, and the motor torque density is significantly improved, which can meet the requirements of high efficiency and miniaturization.

[0029] The present invention also provides a DC variable frequency compressor, comprising the above-mentioned motor. The DC variable frequency compressor has greatly improved performance due to the use of the motor.

[0030] In an application, the motor pole number p=3, under the same rotor outer diameter, the motor rotor with V-shaped magnet slot structure increases the amount of permanent magnets by 14.7% compared with the existing motor rotor with permanent magnets placed orthogonally to the rotor diameter, thereby reducing the operating current and improving the motor efficiency. Figure 2 The arrangement is carried out in the following manner: the length of L1 is d = 23.8 mm, the angle between L1 and L2 is α = 0.46 rad, the distance is b = 24.8 mm, and the following conditions are satisfied:

[0031]

[0032] At this time, the mechanical strength of the rotor can meet the requirements, and at the same time, the significant increase in the magnetic resistance on the rotor side is avoided, thereby increasing the rotor refrigerant flow area while ensuring the performance and reliability of the motor. When it is applied to a DC variable frequency compressor, it can significantly promote the circulation of the refrigerant in the compressor and achieve the purpose of cooling the rotor.

[0033] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A motor rotor, characterized in that: A shaft hole for passing the shaft is arranged at the center of the rotor core of the motor rotor, and a magnet slot, a rivet hole, a secondary refrigerant hole and a main refrigerant hole are also arranged on the rotor core on the periphery of the shaft hole. The magnet slot is in a V-shaped structure for embedded fixed installation of permanent magnets, and the magnetic poles of the permanent magnets placed in adjacent V-shaped magnet slots are opposite; the secondary refrigerant hole is arranged between the V-shaped magnet slot and the shaft hole; the main refrigerant hole is arranged between adjacent V-shaped magnet slots; a V-shaped permanent magnet is placed in each V-shaped magnet slot, or a linear permanent magnet is placed in each of the two linear slots of each V-shaped magnet slot, and the two linear permanent magnets are placed in a manner with the same magnetic pole polarity; The line from the center of the shaft hole to the outermost end of the main refrigerant through hole in the radial direction is defined as L1, and its length is d; the line from the center of the shaft hole to the top corner of the V-shaped magnet slot close to the shaft hole is defined as L2, and the angle between the line segment L1 and the line segment L2 is α; the distance from the center of the shaft hole to the line between the two top corners of the V-shaped magnet slot close to the shaft hole is defined as b, and it satisfies: Where p is the number of pole pairs of the motor.

2. The motor rotor according to claim 1, characterized in that: The main refrigerant through hole and the auxiliary refrigerant through hole are in the shape of a circle, an ellipse, an arc, an arc with line segments or a rectangle.

3. The motor rotor according to claim 1, characterized in that: At least one main refrigerant through hole is connected to an oil return through hole along the outer side of the rotor core in the radial direction.

4. The motor rotor according to claim 3, characterized in that: The shape of the oil return through hole is semicircle, semi-ellipse, arc, arc with line segments or rectangle.

5. The motor rotor according to claim 3, characterized in that: The length d1 of the oil return hole in the circumferential direction of the rotor core satisfies d1≤d3 / 2, and the length d2 of the oil return hole in the radial direction of the rotor core satisfies d2≥d3 / 16, wherein d3 is the length of the refrigerant hole connected to the oil return hole in the circumferential direction of the rotor core.

6. The motor rotor according to claim 1, characterized in that: The rotor core includes rotor punchings of the same shape and is stacked by the rotor punchings.

7. An electric motor, characterized in that: The invention comprises a stator and the motor rotor according to any one of claims 1 to 6, wherein the motor rotor is installed in the stator for rotation via a rotating shaft.

8. A DC variable frequency compressor, characterized in that: Includes the electric motor as claimed in claim 7.

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