Rotor suitable for high-speed permanent magnet synchronous motor and high-speed permanent magnet synchronous motor

Abstract

The utility model relates to a rotor suitable for a high-speed permanent magnet synchronous motor and the high-speed permanent magnet synchronous motor. The rotor comprises a rotating shaft, magnetic steel and a fixing frame. The middle part of the rotating shaft is a cylinder with a regular polygonal section; the inner side surfaces of the plurality of magnetic steels are respectively attached to the outer side surface of the column body, and the outer side surfaces form a circle outside the column body; and the fixing frame is arranged between the adjacent magnetic steels and is fixedly connected with the column body, and the magnetic steels are pressed by two side ends of the fixing frame. A plurality of air grooves are arranged on the binding surface of the magnetic steel and the rotating shaft, namely on the surface of the rotating shaft, so that the cooling gas can directly cool the magnetic steel, and simultaneously the cooling gas flows through the rotating shaft and the magnetic steel to take away heat in a heat conduction mode, thereby reducing the temperature of the magnetic steel and ensuring that the motor is not subjected to thermal demagnetization. The problem that the temperature rise of the magnetic steel of the motor rotor is caused by poor heat conduction capability of the sheath when a high-power high-speed motor adopts a carbon fiber sheath is effectively solved, the heat dissipation capability of the motor rotor and the reliability of the motor are remarkably improved, and the high-power high-speed motor rotor has very high practicability and wide applicability.

Description

Technical Field

[0001] The utility model relates to a rotor applicable to a high-speed permanent magnet synchronous motor, in particular to a rotor applicable to a high-speed permanent magnet synchronous motor and a high-speed permanent magnet synchronous motor, belonging to the technical field of permanent magnet synchronous motors. Background Art

[0002] At present,

[0003] Due to the advantages of high power density, high efficiency, and direct connection with the load, high-speed permanent magnet synchronous motors are widely used in centrifugal compressors, centrifugal blowers, high-speed generators and other fields.

[0004] For such high-speed motors, a surface-mounted high-speed rotor structure is mostly adopted. The rotor consists of a cylindrical permanent magnet, a short shaft, and a sheath, forming a three-section structure. The interference fit between the sheath and the permanent magnet and the short shaft respectively ensures the strength of the rotor during high-speed operation.

[0005] The cooling of the rotor of such motors mainly adopts air cooling. By introducing air into the air gap between the stator and the rotor, the rotor is cooled. Since both the sheath and the permanent magnet are made of metal materials with high thermal conductivity, the heat inside the sheath and the permanent magnet can be easily conducted out and taken away by air cooling, thus realizing the cooling of the rotor.

[0006] However, for motors with a power greater than 250kW and a speed exceeding 30,000 revolutions per minute, due to rotor strength reasons, the alloy sheath (yield strength 1050Mpa) must be replaced with a carbon fiber sheath with a higher yield strength (greater than 1500Mpa). However, the carbon fiber sheath has poor heat conduction in the thickness direction, generally only 0.5 - 2W / mK. The heat inside the permanent magnet cannot be effectively conducted out through the sheath during high-speed rotation. Therefore, the existing air-cooling structure generally only cools the surface of the rotor through the air gap between the stator and the rotor, and cannot effectively cool the permanent magnet inside the rotor. Summary of the Invention

[0007] To solve the deficiencies of the prior art, the purpose of the utility model is to provide a rotor and a cooling structure for a high-speed permanent magnet synchronous motor.

[0008] To achieve the above objectives, the utility model adopts the following technical solutions:

[0009] A rotor applicable to a high-speed permanent magnet synchronous motor includes a rotating shaft, a permanent magnet, and a fixing frame;

[0010] The middle part of the rotating shaft is a column with a regular polygon cross-section;

[0011] A number of permanent magnets are respectively attached to the outer side of the column with their inner sides, and a circle is formed outside the column with their outer sides;

[0012] The fixed frame is arranged between adjacent magnetic steels and fixedly connected to the column, and presses the magnetic steels with its two side ends.

[0013] The above-mentioned regular polygons include regular quadrilaterals, regular pentagons, and regular hexagons.

[0014] Along the axial direction, a plurality of air grooves are arranged on the outer side surface of the column.

[0015] There are at least two air ducts.

[0016] Baffles for limiting the magnetic steel are respectively provided at both ends of the column.

[0017] Furthermore, the magnetic steel and the fixing frame are wrapped by a carbon fiber sheath.

[0018] Furthermore, along the axial direction, the outer side surface of the column is provided with a plurality of wind slots penetrating the baffles on both sides.

[0019] The fitting surface between the magnetic steel and the rotating shaft may also be a curved surface.

[0020] A high-speed permanent magnet synchronous motor comprises the above-mentioned rotor suitable for the high-speed permanent magnet synchronous motor.

[0021] The above motor is a 2-pole motor or a 4-pole motor.

[0022] The utility model is beneficial in that:

[0023] The utility model is a rotor suitable for high-speed permanent magnet synchronous motor and a high-speed permanent magnet synchronous motor. By setting a plurality of wind slots on the fitting surface of the magnetic steel and the rotating shaft, specifically on the side of the rotating shaft, the cooling gas can directly cool the magnetic steel. At the same time, the cooling gas flows through the rotating shaft and the magnetic steel to take away the heat by heat conduction, thereby reducing the magnetic steel temperature and ensuring that the motor does not suffer from thermal demagnetization. The utility model effectively solves the problem of the temperature rise of the motor rotor magnetic steel caused by the poor thermal conductivity of the carbon fiber sheath when a high-power high-speed motor is used, which can significantly improve the heat dissipation capacity of the motor rotor and the reliability of the motor, and has strong practicality and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the rotor structure.

[0025] Figure 2 A cross-sectional view showing a schematic diagram of the rotor structure.

[0026] Figure 3 Schematic diagram of the rotor structure without the carbon fiber sheath.

[0027] Figure 4 It is a schematic diagram of the structure of the rotating shaft.

[0028] The meanings of the marks in the attached drawings are as follows: 1. Rotating shaft, 2. Permanent magnet, 3. Fixed bracket, 4. Fastening screw, 5. Carbon fiber protective sleeve, 6. Air groove, 7. Screw hole, 8. Baffle, 9. Middle part. Detailed implementation mode

[0029] The following specifically introduces the present utility model in combination with the attached drawings and specific embodiments.

[0030] A high-speed permanent magnet synchronous motor, the rotor of which is composed of a rotating shaft 1, a permanent magnet 2 and a fixed bracket 3.

[0031] The rotating shaft is composed of a regular polygon column body in the middle part 9 and a cylinder at both ends; and baffle plates are respectively arranged at both ends of the regular polygon column body. The regular polygon can be a regular quadrilateral, a regular pentagon, a regular hexagon, etc. Preferably, as Figure 2 shown, the regular polygon is a square. The baffle plate is a circular baffle plate.

[0032] Along the axis, several air grooves 6 are respectively arranged on the surface of the square column body, and the air grooves respectively penetrate through the baffle plates at both ends. The number of air grooves on one side of the column body is not less than 2. Preferably, as Figure 3 shown, the number of air grooves is 3, and the groove depth of the air groove in the middle is greater than the groove depths of the air grooves on both sides of it.

[0033] Matched with the square column body, there are 4 permanent magnets. The inner side surface of the permanent magnet adheres to one side surface of the square column body. The outer side surface of the permanent magnet is arc-shaped, and the arcs of the outer side surfaces of the 4 permanent magnets surrounding the square column body are sequentially connected to form a circle.

[0034] The permanent magnet is fixed by a fixed bracket. The fixed bracket is arranged between adjacent permanent magnets and is screwed to the screw hole 7 on the square column body through a fastening screw 4. The permanent magnet is pressed by both sides of the fixed bracket, so that the permanent magnet is just in contact with the square column body. The outer surface of the fixed bracket and the outer surface of the permanent magnet form a complete circle.

[0035] Both ends of the permanent magnet are blocked by a baffle plate 8. To further strengthen the firmness of the connection, the permanent magnet can also be adhered to the middle part of the rotating shaft, that is, the surface of the square column body, through a high-temperature resistant epoxy adhesive.

[0036] The carbon fiber protective sleeve 5 is sleeved outside the rotor by winding or cold fitting methods, wrapping the baffle plate, permanent magnet, fixed bracket and fastening screw, providing support for the high-speed operation of the rotor and ensuring the strength of the rotor. Preferably, the material of the carbon fiber protective sleeve can be high-strength carbon fiber materials such as T700, T800 or M40J.

[0037] Preferably, the high-speed permanent magnet synchronous motor is a 2-pole motor or a 4-pole motor.

[0038] Preferably, the joint surface between the permanent magnet and the rotating shaft can also be an arc surface.

[0039] During use,

[0040] The cooling gas is provided by an external independent fan and enters the motor internally in the radial direction.

[0041] After entering the motor, a part of the cooling gas cools the rotor and stator windings through the end of the winding package and the air gap between the stator and rotor. Another part of the cooling gas, as Figure 1 shown, after passing through the air duct from the right inlet, flows out from the left side to take away the heat generated by the permanent magnet.

[0042] After the cooling gas meets at the other side of the motor, it passes through the end of the winding package again and flows out of the motor in the radial direction.

[0043] The above shows and describes the basic principle, main features and advantages of the present utility model. Those skilled in the art should understand that the above embodiments do not limit the present utility model in any form. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present utility model.

Claims

1. A rotor suitable for a high-speed permanent magnet synchronous motor, characterized in that: Including a rotating shaft, a magnetic steel and a fixing frame; The middle part of the rotating shaft is a cylinder with a regular polygonal cross section; A plurality of magnetic steels are respectively attached with their inner sides to the outer sides of the cylinder, and their outer sides form a circle outside the cylinder; The fixed frame is arranged between adjacent magnetic steels and fixedly connected to the column, and presses the magnetic steels with its two side ends.

2. The rotor according to claim 1, characterized in that The regular polygons include regular quadrilaterals, regular pentagons, and regular hexagons.

3. The rotor according to claim 1, characterized in that A plurality of air grooves are arranged on the outer side surface of the column along the axial direction.

4. The rotor according to claim 3, characterized in that There are at least two air ducts.

5. The rotor according to claim 1, characterized in that Baffles for limiting magnetic steel are respectively arranged at both ends of the column.

6. The rotor according to claim 5, characterized in that The magnetic steel and the fixing frame are wrapped by a carbon fiber sheath.

7. The rotor according to claim 5, characterized in that Along the axial direction, the outer side surface of the column is provided with a plurality of wind slots penetrating the baffles on both sides.

8. The rotor according to claim 1, characterized in that The fitting surface between the magnetic steel and the rotating shaft may also be a curved surface.

9. A high-speed permanent magnet synchronous motor, characterized in that: It comprises a rotor suitable for a high-speed permanent magnet synchronous motor according to any one of claims 1-8.

10. The high-speed permanent magnet synchronous motor according to claim 9, characterized in that: The motor is a 2-pole motor or a 4-pole motor.

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