A high-speed permanent magnet motor internal circulation ventilation rotor and its preparation method

Abstract

This invention discloses a high-speed permanent magnet motor internal circulation ventilation rotor and its manufacturing method, relating to the field of motor rotor manufacturing technology. The rotor includes a rotating shaft, a silicon steel sheet ring, a permanent magnet, and a sheath arranged concentrically from the inside out. The rotating shaft has a built-in straight-sloping ventilation duct, and the silicon steel sheet ring has a built-in spiral ventilation duct. The straight-sloping and spiral ventilation ducts together constitute the internal circulation ventilation system of the rotor. The straight-sloping ventilation duct utilizes the pressure difference formed at both ends of the duct during high-speed rotor rotation to drive cooling air to flow axially; while the spiral ventilation duct utilizes the centrifugal effect generated during rotation to drive gas to move along a spiral trajectory. The two ventilation ducts have opposite airflow directions and are connected by air chambers at both ends of the rotor, achieving self-circulation of air inside the motor rotor, enhancing the rotor cooling effect, and providing an effective way to solve the bottleneck problem of excessive temperature rise in high-speed permanent magnet motor rotors.

Description

Technical Field

[0001] This invention relates to the field of motor rotor manufacturing technology, and in particular to a high-speed permanent magnet motor internal circulation ventilation rotor and its manufacturing method. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure and do not necessarily constitute prior art.

[0003] High-speed permanent magnet motors, due to their advantages such as high power density, high efficiency, wide speed range, and fast dynamic response, have broad application prospects in high-end equipment manufacturing industries such as aerospace and flywheel energy storage. Currently, with the continuous upgrading of market demand, high-speed permanent magnet motors are developing towards higher power and higher speeds. However, due to their compact structure and limited rotor heat dissipation paths, the motor rotor is constantly subjected to harsh conditions of high temperature and high speed, always facing the risk of high-temperature demagnetization. This bottleneck not only severely restricts the research and development process of high-performance high-speed permanent magnet motors but has also become a key technological obstacle affecting their long-term development.

[0004] Currently, research and application of motor cooling technology mainly focus on the stator side, while related cooling technologies for the rotor side are extremely limited. Existing technologies propose an intelligent heat dissipation method, device, and system for permanent magnet synchronous motors. This method dynamically monitors the heat exchange zone and matches the cooling pump power, but it does not address rotor cooling technology. Existing technologies propose a fully immersed oil-cooled winding stator assembly. This method mainly targets the overall cooling of the windings and does not address rotor cooling technology. Existing technologies propose a motor cooling system and motor. This device includes internal and external rotor oil circuits and stator oil circuits, comprehensively cooling all component assemblies. However, issues such as oil circuit sealing limit the application of this method to high-speed motor rotors. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a high-speed permanent magnet motor internal circulation ventilation rotor and its preparation method, aiming to solve the problem of high-temperature demagnetization of permanent magnets caused by excessive rotor temperature rise in high-speed permanent magnet motors.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] In a first aspect, the present invention provides a high-speed permanent magnet motor internal circulation ventilation rotor, comprising a rotating shaft, a silicon steel sheet ring, a permanent magnet and a sheath arranged concentrically from the inside to the outside;

[0008] The rotating shaft has a built-in straight and inclined ventilation duct, and the silicon steel sheet ring has a built-in spiral ventilation duct. The straight and inclined ventilation ducts and the spiral ventilation duct together constitute the internal circulation ventilation system inside the rotor.

[0009] A further technical solution is to reverse the airflow direction in a straight-sloping ventilation duct compared to a spiral ventilation duct.

[0010] In a further technical solution, the rotating shaft is drilled with multiple straight and inclined ventilation channels along the circumferential direction.

[0011] A further technical solution is to implement the straight and inclined ventilation duct through a two-stage drilling process.

[0012] A further technical solution is that the straight-inclined ventilation duct includes an axial ventilation duct and an inclined ventilation duct that intersect and connect, with the inclined ventilation duct being radially inclined.

[0013] In a further technical solution, the straight and inclined ventilation duct utilizes the velocity difference between the two ventilation openings to create a pressure difference, thereby driving the gas flow within the ventilation duct.

[0014] In a further technical solution, the spiral ventilation duct is formed by rotating and stacking multiple single-layer silicon steel sheet rings.

[0015] In a further technical solution, the single-layer silicon steel sheet ring is punched with multiple ventilation holes at intervals along the circumference.

[0016] A further technical solution involves stacking adjacent single-layer silicon steel sheet rings in a staggered manner at a certain spiral angle to form a continuous spiral ventilation channel, using the thrust generated by the centrifugal effect of air at high speed to drive its flow in the ventilation channel.

[0017] Secondly, the present invention provides a method for manufacturing a high-speed permanent magnet motor internal circulation ventilation rotor, comprising:

[0018] Mark the positions of the ventilation openings on both sides of the shaft, and drill axial holes and radial inclined holes according to the marked positions on both sides. The axial ventilation channel and the inclined ventilation channel intersect and connect to form a shaft with straight and inclined ventilation channels.

[0019] Make a positioning wire with a certain spiral angle, punch multiple ventilation holes in a single-layer silicon steel sheet ring along the circumference, stack multiple single-layer silicon steel sheet rings axially according to the positioning wire trajectory, and remove the positioning wire after stacking to obtain a silicon steel sheet ring with a spiral ventilation channel.

[0020] The rotating shaft containing the straight and inclined ventilation ducts and the silicon steel sheet ring containing the spiral ventilation ducts are installed by interference fit, and after being installed with the permanent magnet and the sheath, a high-speed permanent magnet motor internal circulation ventilation rotor is obtained.

[0021] The above one or more technical solutions have the following beneficial effects:

[0022] The high-speed permanent magnet motor's internally ventilated rotor incorporates two independent ventilation duct types: a straight-sloping ventilation duct built into the rotor shaft and a spiral ventilation duct built into a silicon steel sheet ring. The straight-sloping ventilation duct creates a pressure gradient by constructing a speed difference between the two ventilation openings, driving gas flow within the channel; the spiral ventilation duct utilizes the centrifugal effect of air under high-speed rotation to generate thrust, causing gas to flow along a spiral path. These two ventilation ducts have opposite airflow directions, connected by air chambers at both ends of the rotor, achieving self-circulation of air within the motor rotor. This enhances rotor cooling and provides an effective solution to the bottleneck problem of excessive rotor temperature rise in high-speed permanent magnet motors.

[0023] The straight-sloping air duct utilizes the pressure difference created at both ends of the duct during high-speed rotor rotation to drive cooling air axially; while the spiral air duct uses the centrifugal effect generated during rotation to drive gas along a spiral trajectory. The airflow directions in the two types of ducts are opposite, with the rotor's double-end air chambers serving as a transition, creating a self-circulating ventilation system within the motor. This provides an effective heat dissipation path for the high-speed permanent magnet motor rotor, significantly reducing rotor temperature rise. This effectively solves the problem of high-temperature demagnetization of permanent magnets due to excessive rotor temperature rise in high-speed permanent magnet motors, laying a key technological foundation for the development of high-speed permanent magnet motors towards higher power and higher speeds. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0025] Figure 1 This is a schematic diagram of the structure of an internal circulation ventilation rotor for a high-speed permanent magnet motor according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the cross-section of the straight and inclined ventilation duct inside the rotating shaft according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the spiral ventilation channel inside the silicon steel sheet ring according to an embodiment of the present invention;

[0028] Figure 4 This is a flowchart of a method for preparing a high-speed permanent magnet motor internal circulation ventilation rotor according to an embodiment of the present invention;

[0029] Among them, the rotating shaft-1, silicon steel sheet ring-2, permanent magnet-3, sheath-4, straight and inclined ventilation duct-5, spiral ventilation duct-6, straight and inclined ventilation duct inlet-7a, straight and inclined ventilation duct outlet-7b, spiral ventilation duct outlet-8a, and spiral ventilation duct inlet-8b. Detailed Implementation

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0031] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0032] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0033] Example 1

[0034] like Figure 1 , Figure 2 As shown, this embodiment discloses a high-speed permanent magnet motor internal circulation ventilation rotor, including a rotating shaft 1, a silicon steel sheet ring 2, a permanent magnet 3 and a sheath 4 arranged concentrically from the inside to the outside;

[0035] The rotating shaft 1 has a built-in straight and inclined ventilation duct 5, and the silicon steel sheet ring 2 has a built-in spiral ventilation duct 6. The straight and inclined ventilation duct 5 and the spiral ventilation duct 6 together constitute the internal circulation ventilation system inside the rotor.

[0036] The straight and inclined ventilation duct 5 and the spiral ventilation duct 6 need to coexist to achieve the effect of internal circulation cooling of the rotor. The rotor uses the speed difference between the ventilation openings on both sides of the straight and inclined ventilation duct 5 to form a pressure gradient. The spiral ventilation duct 6 generates thrust due to the centrifugal effect of the air under high-speed rotation, driving the gas to flow in the channel. The air flow directions of the two ventilation ducts are opposite. They are connected by the air chambers at both ends of the rotor to realize the self-circulation of air inside the motor rotor, which enhances the rotor cooling effect and solves the bottleneck problem of high temperature rise of the rotor of high-speed permanent magnet motor.

[0037] In this embodiment, the sheath 4 is made of carbon fiber.

[0038] In this embodiment, the straight and inclined ventilation duct 5 inside the rotating shaft 1 is achieved through a two-stage drilling process.

[0039] like Figure 2As shown, the rotating shaft 1 has multiple straight and inclined ventilation ducts 5 drilled along the circumference. The straight and inclined ventilation ducts 5 are divided into two sections along the rotor axis. The first section of the ventilation duct (axial ventilation duct) is parallel to the axis, and the second section of the ventilation duct (inclined ventilation duct) is inclined radially, forming a certain angle with the axis. The airflow direction is from the air inlet 7a of the straight and inclined ventilation duct to the air outlet 7b of the straight and inclined ventilation duct.

[0040] In some embodiments, preferably, 4 to 6 straight and inclined ventilation ducts are drilled.

[0041] In some implementations, the radially inclined ventilation duct forms an angle of 10 to 30° with the axial direction.

[0042] The drilling of the straight and inclined ventilation duct 5 is carried out by machining on both sides of the rotating shaft 1. The axial ventilation duct is machined on one side and the inclined ventilation duct is machined on the other side. Before machining, the machining positions on both sides need to be marked to ensure that the ventilation ducts can meet inside the rotating shaft 1 after machining on both sides. The pressure difference is formed by the speed difference of the ventilation ports on both sides, which drives the gas flow in the ventilation duct to achieve the purpose of rotor cooling.

[0043] In this embodiment, the spiral ventilation channel 6 inside the silicon steel sheet ring 2 is achieved through multi-layer rotation and stacking.

[0044] Multiple ventilation openings are punched at intervals along the circumference of a single-layer silicon steel sheet ring. Positioning steel wires are made according to a spiral trajectory. The silicon steel sheets are stacked according to the positioning steel wires. After stacking, the positioning steel wires are removed.

[0045] In some embodiments, 4 to 6 ventilation holes are punched at intervals on the circumference of the single-layer silicon steel sheet ring. The number of ventilation holes is determined by the power rating of the motor. The ventilation holes are punched at uniform intervals to ensure that the rotor's center of gravity is centered, avoiding mechanical vibration problems caused by rotor eccentricity. The circumferential ventilation holes are evenly distributed; if viewed from any cross-section of the rotor, the ventilation holes are uniformly distributed circumferentially. Furthermore, the number of ventilation holes corresponds to the number of spiral ventilation channels.

[0046] like Figure 3 As shown, the spiral angle of the silicon steel sheet ring 2 is 70~80°. Adjacent silicon steel sheets are stacked in a staggered manner according to the spiral angle to form a through axial spiral ventilation channel. The airflow direction is from the air inlet 8b of the spiral ventilation channel to the air outlet 8a of the spiral ventilation channel. The thrust generated by the centrifugal effect of air at high speed drives its flow in the ventilation channel.

[0047] In this embodiment, the silicon steel sheet ring 2, which contains a spiral ventilation duct and an axial ventilation duct respectively, is installed with the rotating shaft 1 by an interference fit. The rotating shaft 1 is treated with cryogenic liquid nitrogen, and the interference fit is 0.08~0.1mm.

[0048] Mark the rotor rotation direction to ensure that during high-speed rotor rotation, the airflow direction of the spiral duct is opposite to that of the straight and inclined duct. Use the double-ended rotor of the motor rotor as a transition zone to achieve internal air circulation in the motor rotor, thereby achieving efficient cooling of the motor rotor.

[0049] Example 2

[0050] like Figure 4 As shown, this embodiment discloses a method for manufacturing a high-speed permanent magnet motor internal circulation ventilation rotor, including:

[0051] S1: Mark the positions of the ventilation openings on both sides of the rotating shaft 1, and drill axial holes and radial inclined holes according to the marked positions on both sides. The axial ventilation channel and the inclined ventilation channel intersect and connect to form the rotating shaft 1 containing straight and inclined ventilation channels.

[0052] In this embodiment, the angle between the inclined drilling and the axial direction is 15°, and the number of drilling holes is 4.

[0053] S2: Make a positioning steel wire with a certain spiral angle, punch multiple ventilation holes in the single-layer silicon steel sheet ring along the circumferential direction, stack multiple single-layer silicon steel sheet rings axially according to the positioning steel wire trajectory, and remove the positioning steel wire after stacking to obtain a silicon steel sheet ring 2 with a spiral ventilation channel.

[0054] In this embodiment, the helix angle is 70°.

[0055] S3: The rotating shaft 1, containing straight and inclined ventilation ducts, and the silicon steel sheet ring 2, containing spiral ventilation ducts, are installed using an interference fit. After installation with the permanent magnet 3 and the sheath 4, a high-speed permanent magnet motor internal circulation ventilation rotor is obtained. The permanent magnet 3 is bonded to the surface of the silicon steel sheet ring 2 with epoxy resin. After bonding, carbon fiber is wound around the surface of the permanent magnet 3. After multiple layers of winding, a carbon fiber sheath is formed. Finally, a curing treatment is performed to complete the rotor manufacturing.

[0056] In this embodiment, the rotating shaft 1 is treated with cryogenic liquid nitrogen and the interference fit is 0.1 mm.

[0057] The motor rotor structure includes a sintered permanent magnet 3, a carbon fiber sheath, a silicon steel sheet ring 2, and a shaft 1. This rotor structure incorporates two independent ventilation duct types: a straight-inclined ventilation duct 5 built into the shaft 1 and a spiral ventilation duct built into the silicon steel sheet ring 2. The straight-inclined ventilation duct 5 creates a pressure gradient by constructing a speed difference between the two ventilation openings, driving gas flow within the channel; the spiral ventilation duct 6 utilizes the centrifugal effect of air under high-speed rotation to generate thrust, causing gas to flow along a spiral path. These two ventilation ducts have opposite airflow directions, connected by air chambers at both ends of the rotor, achieving internal air circulation within the motor rotor. This enhances the rotor cooling effect and provides an effective way to solve the bottleneck problem of excessive temperature rise in high-speed permanent magnet motor rotors.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0059] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A high speed permanent magnet machine inner circulating ventilation rotor, characterized in that, It includes a rotating shaft, a silicon steel sheet ring, a permanent magnet, and a sheath arranged concentrically from the inside out; The rotating shaft has built-in straight and inclined ventilation ducts, and the silicon steel sheet rings have built-in spiral ventilation ducts. The straight and inclined ventilation ducts and the spiral ventilation ducts together constitute the internal circulation ventilation system inside the rotor. Specifically, the rotating shaft is drilled with multiple straight and inclined ventilation ducts along the circumferential direction. The straight and inclined ventilation ducts are divided into two sections along the rotor axis. The axial ventilation duct is parallel to the axial direction, and the inclined ventilation duct is inclined radially outward, forming a certain angle with the axial direction. The airflow direction is from the air inlet of the straight and inclined ventilation duct to the air outlet of the straight and inclined ventilation duct. The air inlet and air outlet of the straight and inclined ventilation duct are located at both ends of the rotating shaft. The spiral ventilation duct is formed by rotating and stacking multiple single-layer silicon steel sheet rings. Adjacent single-layer silicon steel sheet rings are stacked in a staggered manner according to a certain spiral angle to form a through spiral ventilation duct. Its airflow direction is from the air inlet of the spiral ventilation duct to the air outlet of the spiral ventilation duct. The rotor utilizes the speed difference between the ventilation openings on both sides of the straight and inclined ventilation duct to create a pressure gradient. The centrifugal effect of the air in the spiral ventilation duct under high-speed rotation drives the gas to flow in the channel. The air flow direction in the straight and inclined ventilation duct is opposite to that in the spiral ventilation duct. The air chambers at both ends of the rotor are connected to realize the self-circulation of air inside the motor rotor.

2. The high-speed permanent magnet motor internal circulation ventilation rotor as described in claim 1, characterized in that, The straight and inclined ventilation duct is achieved through a two-stage drilling process.

3. The high-speed permanent magnet motor internal circulation ventilation rotor as described in claim 2, characterized in that, The straight-inclined ventilation duct includes an axial ventilation duct and an inclined ventilation duct that intersect and connect, with the inclined ventilation duct being radially inclined.

4. The high-speed permanent magnet motor internal circulation ventilation rotor as described in claim 1, characterized in that, The single-layer silicon steel sheet ring has multiple ventilation holes punched at intervals along its circumference.

5. A method for manufacturing a high-speed permanent magnet motor internal circulation ventilation rotor, comprising using a high-speed permanent magnet motor internal circulation ventilation rotor as described in any one of claims 1-4, characterized in that, include: Mark the positions of the ventilation openings on both sides of the shaft, and drill axial holes and radial inclined holes according to the marked positions on both sides. The axial ventilation channel and the inclined ventilation channel intersect and connect to form a shaft with straight and inclined ventilation channels. Make a positioning wire with a certain spiral angle, punch multiple ventilation holes in a single-layer silicon steel sheet ring along the circumference, stack multiple single-layer silicon steel sheet rings axially according to the positioning wire trajectory, and remove the positioning wire after stacking to obtain a silicon steel sheet ring with a spiral ventilation channel. The rotating shaft containing the straight and inclined ventilation ducts and the silicon steel sheet ring containing the spiral ventilation ducts are installed by interference fit, and after being installed with the permanent magnet and the sheath, a high-speed permanent magnet motor internal circulation ventilation rotor is obtained.

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