A permanent magnet motor rotor

Abstract

The application discloses a permanent magnet motor rotor, which comprises a ring columnar iron core formed by laminating a plurality of silicon steel sheets; a magnetic steel channel extending along an axial direction is formed through the ring columnar iron core near an outer circumferential surface; a front end ring and a rear end ring are tightly attached to front and rear ends of the ring columnar iron core respectively; the front end ring and the rear end ring respectively block front and rear ends of each magnetic steel channel; a screw rod through channel extending along the axial direction is formed through a combined structure formed by the ring columnar iron core and the rear end ring; a screw rod passes through the screw rod through channel; an a nut is threadedly connected to a rear end of the screw rod, and the a nut presses an outer end surface of the rear end ring through an a anti-loosening gasket assembly; a b nut and a c nut are threadedly connected to a front end of the screw rod, and the b nut is closer to the ring columnar iron core than the c nut; the application solves the problem of iron core loosening during assembly and replacement, and strengthens heat dissipation performance.

Description

Technical Field

[0001] This invention belongs to the field of electric motors. Background Technology

[0002] The magnets in a permanent magnet motor are the core components used to generate the magnetic field. A typical existing permanent magnet rotor structure is as follows: Figure 1 As shown, a plurality of magnetic steel channels 31 extending along the axial direction are provided through the annular columnar iron core 3. A plurality of adjacent permanent magnet steel units 2 are arranged in an array along the length direction in each magnetic steel channel 31. The front end ring 6 and the rear end ring 1 are respectively attached to the front and rear ends of the annular columnar iron core 3. The front end ring 6 and the rear end ring 1 respectively block the front and rear ends of the magnetic steel channels 31. The front end ring 6 and the rear end ring 1 are locked by the screw 4 and the nuts at both ends of the screw 4, so that the front end ring 6 and the rear end ring 1 exert a clamping pressure on the annular columnar iron core 3, thereby preventing the silicon steel sheets on the annular columnar iron core 3 from loosening. At the same time, the front end ring 6 and the rear end ring 1 play the role of encapsulating the magnetic steel channels 31.

[0003] Although this type of permanent magnet rotor has the advantage of simple structure, the process of inserting the permanent magnet unit 2 into the magnet channel 31 requires relieving the clamping pressure of the front ring 6 and the rear ring 1 on the annular core 3 and removing one of the front ring 6 and the rear ring 1 before the permanent magnet unit 2 can be inserted. This will cause the silicon steel sheets on the annular core 3 to loosen. Even if the nuts at both ends are tightened again after the permanent magnet unit 2 is fully inserted, this loosening between the rotor laminations is irreversible. This directly leads to the rotor generating vibration and noise when the motor speed and torque are high, affecting the stable operation of the motor. At the same time, the eddy currents inside the annular core 3 will generate heat when running at high speed, and the heat inside the traditional permanent magnet rotor is difficult to dissipate. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a permanent magnet motor rotor that solves the problem of loose iron core during assembly and enhances heat dissipation performance.

[0005] Technical solution: To achieve the above objective, a permanent magnet motor rotor includes a ring-shaped iron core made of several thin silicon steel sheets stacked together; a magnet channel extending along the axial direction is penetrated in the ring-shaped iron core near its outer circumference; a front ring and a rear ring are respectively attached to the front and rear ends of the ring-shaped iron core; the front ring and the rear ring respectively block the front and rear ends of each magnet channel.

[0006] The combined structure consisting of the annular core and the rear ring has a through-channel extending along the axial direction, through which the screw passes. The rear end of the screw is threaded with nut a, which presses against the outer end face of the rear ring via an anti-loosening washer assembly a. The front end of the screw is threaded with nuts b and c, with nut b being closer to the annular core than nut c. Nut b presses against the front end face of the annular core via an anti-loosening washer assembly b. The front ring has a nut sleeve with a cutout, inside which nut b is fitted, and an annular space is formed between the outer circumference of nut b and the inner ring of the nut sleeve.

[0007] There is a force transmission ring on the outer side of the nut sleeve, and the area enclosed by the force transmission ring is the nut chamber. Nut b is in the nut chamber. On the side of each force transmission ring away from the front ring, there is a disc-shaped washer on the coaxial side. Nut c presses the disc-shaped washer away from the force transmission ring through the c anti-loosening washer assembly. The pushing force of nut c is transmitted to the front ring through the force transmission ring, so that the front ring fits tightly against the ring column iron core.

[0008] Furthermore, both nut b and nut c ultimately transmit pressure to the front end of the annular cylindrical iron core. Before the process of inserting the magnet channel into the permanent magnet unit, with both nut a and nut b in a tightened state, after removing each nut c and taking off the front end ring, the magnet channel at the front end of the annular cylindrical iron core in a stable state is exposed and connected to the outside.

[0009] Furthermore, each magnet channel contains several adjacent permanent magnet units arranged in an array along its length.

[0010] Furthermore, each force transmission ring has a partial hollowed-out opening with a notch, located on each force transmission ring at the position furthest from the axis of the annular cylindrical iron core; the nut compartment is connected to the outside through the notch; the combined structure formed by the annular cylindrical iron core and the rear ring has several air ducts running along the axial direction, and the front end of each air duct is connected to the nut compartment.

[0011] Furthermore, during the assembly process, before finally tightening the C nut, the force transmission ring needs to be rotated until the open notch of the force transmission ring is rotated to the position furthest away from the axis of the ring-shaped iron core. Once in position, tighten the C nut.

[0012] Furthermore, each force transmission ring is a complete circular ring, and the nut compartment is surrounded and wrapped by the force transmission rings with a complete circular structure. The force transmission rings are made of thermally conductive metal and have thermally conductive fins on their inner and outer walls. The combined structure formed by the annular columnar iron core and the rear end ring has several distal air channels and several proximal air channels running through it along the axial direction. The distal air channels are on the side of the screw away from the axis of the annular columnar iron core, and the proximal air channels are on the side of the screw close to the axis of the annular columnar iron core. The front ends of both the distal and proximal air channels are connected to the nut compartment.

[0013] Furthermore, when the permanent magnet rotor rotates at high speed around the axis of the cylindrical iron core as a whole, the air pressure at the connection between the near-center air duct and the nut chamber is lower than the air pressure at the connection between the far-center air duct and the nut chamber. Therefore, under the action of the air pressure difference, the following "internal gas circulation" is formed: the rear end of the near-center air duct continuously draws away the air at the rear end of the stator and rotor chamber, the gas drawn into the near-center air duct continuously flows forward into the nut chamber, and the air flowing into the nut chamber continuously flows into the front end of the far-center air duct. The gas entering the far-center air duct is finally discharged from the rear end back to the rear end of the stator and rotor chamber.

[0014] Technical effect: The core concept of this invention lies in decoupling the two major functions of "iron core clamping" and "magnetic steel encapsulation", and further integrating a highly efficient self-cooling system on this basis.

[0015] Functional decoupling: Nut b directly clamps the front end of the iron core, undertaking the main function of iron core clamping; while nut c clamps the front end ring through the force transmission ring, mainly undertaking the function of encapsulating the magnet channel. The two work together to form a double anti-loosening safety.

[0016] Non-destructive maintenance: When assembling or replacing magnets, only nut c and the front ring need to be removed, while nuts a and b remain locked. This ensures that the core remains stably clamped throughout the process, fundamentally solving the problem of silicon steel sheets loosening during maintenance and improving the maintainability and long-term operational reliability of the rotor.

[0017] The first embodiment is innovative: a self-cooling air duct system based on centrifugal force has an open-loop notch located at the farthest position on the force transmission ring; when the rotor rotates at high speed, the centrifugal force throws the air in the nut chamber out through the open-loop notch, forming a negative pressure, which drives the cooling airflow to be drawn in from the air duct at the rear of the iron core, flows through the inside of the iron core, and completes a gas internal circulation; it realizes self-driven cooling without the need for an external fan, effectively reducing the temperature of the iron core, and the air duct is arranged in a low magnetic flux density area, avoiding additional eddy current losses.

[0018] The second embodiment is innovative: a composite cooling system based on air pressure difference and mid-course heat dissipation. It adopts a complete circular force transmission ring and designs it as a finned heat conductor. At the same time, it sets up a distal air duct and a proximal air duct. Utilizing the radial air pressure difference formed in the sealed nut chamber when the rotor rotates, the airflow is driven to flow in from the proximal air duct, and after passing through the nut chamber, it flows out from the distal air duct, forming another path of internal gas circulation. The air pressure difference drive is stable and reliable. More importantly, the hot airflow flowing through the nut chamber is "cooled down midway" by the heat-conducting force transmission ring, which is equivalent to adding an intercooler and improving the heat dissipation efficiency of the entire cooling system. It is particularly suitable for high power density motors.

[0019] In summary, this solution not only solves the inherent reliability problem of existing rotor structures through ingenious mechanical structure design, but also innovatively utilizes the rotor's own dynamic characteristics to derive two efficient internal circulation cooling schemes. While improving structural stability and maintainability, it significantly enhances heat dissipation performance, demonstrating a high degree of creativity and completeness. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an existing permanent magnet rotor structure;

[0021] Figure 2 This is a schematic diagram of the permanent magnet rotor of this scheme from a first-person perspective;

[0022] Figure 3 for Figure 2 Disassembly diagram from a specific perspective;

[0023] Figure 4 This is a schematic diagram of the permanent magnet rotor of this scheme from a second perspective;

[0024] Figure 5 This is a schematic diagram of the structure of the "first embodiment";

[0025] Figure 6 This is a schematic diagram of the "second embodiment". Detailed Implementation

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] like Figures 2 to 6 As shown, a novel permanent magnet motor rotor includes a ring-shaped iron core 3 formed by stacking several thin silicon steel sheets. The ring-shaped iron core 3 is usually formed by stacking cold-rolled silicon steel sheets with a thickness of 0.35mm to 0.5mm. The permanent magnet steel units 2 in the magnet channels 31 are mostly made of sintered NdFeB material. Several magnet channels 31 extending along the axial direction are arranged in a circular array near the outer circumference of the ring-shaped iron core 3. Several adjacent permanent magnet steel units 2 are arranged in an array along the length direction in each magnet channel 31. The front end ring 6 and the rear end ring 1 are respectively attached to the front and rear ends of the ring-shaped iron core 3. The front end ring 6 and the rear end ring 1 respectively block the front and rear ends of each magnet channel 31.

[0028] The combined structure formed by the annular core 3 and the rear ring 1 has a circular array of screws extending along the axial direction through the channel 51. Each screw has a screw 4 with external threads at both ends passing through the channel 51. The rear thread of the screw 4 is fitted with a nut 21. The nut 21 presses against the outer end face of the rear ring 1 through the anti-loosening washer assembly 20.

[0029] Each screw 4 has a threaded connection between its front end and a b nut 17 and a c nut 13. The b nut 17 is closer to the annular core 3 than the c nut 13. The b nut 17 presses against the front end face of the annular core 3 through the b anti-loosening washer assembly 22. Several thin silicon steel sheets on the annular core 3 are tightly stacked under the clamping pressure of several a nuts 21 and several b nuts 17.

[0030] The front end ring 6 has several nut slots 16 arranged in a circular array. Each nut slot 16 contains a b nut 17. An annular space is formed between the outer circumference of the b nut 17 and the inner ring of the nut slot 16.

[0031] Each nut sleeve 16 has a corresponding force transmission ring 11 on its outer side, which encloses a nut chamber 35. Nut b 17 is located within the nut chamber 35. A disc-shaped washer 12 is coaxially attached to the side of each force transmission ring 11 away from the front end ring 6. Nut c 13 presses against the side of the disc-shaped washer 12 away from the force transmission ring 11 through the anti-loosening washer assembly 14. The pushing force of nut c 13 is transmitted to the front end ring 6 through the force transmission ring 11, thus making the front end ring 6 tightly fit against the annular core 3. Nut a 21 and nut b 17 provide the main clamping for the annular core 3, while nut c 13 transmits auxiliary pressure through the force transmission ring 11, forming a double anti-loosening structure. When it is necessary to replace the magnet, only nut c 13 and the front end ring 6 are removed, while nut a 21 and nut b 17 remain tightened to ensure that the silicon steel sheets do not loosen, thereby maintaining the dynamic balance of the rotor.

[0032] This novel structure has the following characteristics: both nut b17 and nut c13 ultimately transmit pressure to the front end of the annular columnar iron core 3, providing a double anti-loosening guarantee. Furthermore, based on this new structure, before the process of inserting the permanent magnet unit 2 into the magnet channel 31, each nut c13 can be removed and the front end ring 6 can be taken off, ensuring that both nut a21 and nut b17 are tightened. This exposes the magnet channel 31 at the front end of the annular columnar iron core 3 in a stable state and connects it to the outside world, thus preventing the annular columnar iron core 3 from loosening during the process of inserting the permanent magnet unit 2 into the magnet channel 31. After the permanent magnet unit 2 is inserted into the magnet channel 31, the front end ring 6 is finally installed for sealing.

[0033] Based on the new structure described above, this solution further designs the following two embodiments:

[0034] First embodiment:

[0035] like Figures 2 to 5As shown, each force transmission ring 11 has a partial open-loop notch 15, which is located on each force transmission ring 11 at the position furthest from the axis of the annular columnar iron core 3. The nut chamber 35 is connected to the outside through the open-loop notch 15. Several air ducts 18 are connected along the axial direction on the combined structure formed by the annular columnar iron core 3 and the rear ring 1, and the front end of each air duct 18 is connected to the nut chamber 35. This structure requires that before finally tightening the c nut 13, the force transmission ring 11 needs to be rotated until the open-loop notch 15 of the force transmission ring 11 is rotated to the position furthest from the axis of the annular columnar iron core 3. After it is in place, the c nut 13 can be tightened. The positions of the several air ducts 18 are specifically set in areas with low magnetic flux density to avoid affecting the motor efficiency.

[0036] The principle of the first embodiment:

[0037] When the permanent magnet rotor, based on the structure of the "first embodiment", rotates at high speed around the axis of the annular columnar iron core 3 as a whole, for example, at a speed exceeding 3000 rpm, since each open-ring notch 15 is located at the position furthest from the axis of the annular columnar iron core 3 on each force transmission ring 11, the air in each nut chamber 35 will be continuously thrown outward through each open-ring notch 15 to the front end of the stator and rotor cavity inside the motor under the action of centrifugal force, thereby generating a relative centrifugal negative pressure in each nut chamber 35. The air at the rear end of the stator and rotor cavity inside the motor is drawn into each air duct 18 under the action of negative pressure and continuously replenished into each nut chamber 35. This cycle continues, eventually forming a "gas internal circulation" inside the motor. This gas internal circulation causes the internal circulation gas to flow continuously through each air duct 18, thereby continuously carrying away the heat inside the annular columnar iron core 3 and preventing the annular columnar iron core 3 from overheating.

[0038] Second embodiment:

[0039] like Figure 6 As shown, each force transmission ring 11 is a complete circular ring. The nut chamber 35 is surrounded and wrapped by the force transmission ring 11 with a complete circular structure. The force transmission ring 11 is made of heat-conducting metal, such as aluminum alloy or copper alloy, and has heat-conducting fins on its inner and outer walls. The combined structure formed by the annular columnar iron core 3 and the rear end ring 1 has several distal air channels 18a and several proximal air channels 18b running through it along the axial direction. The distal air channel 18a is on the side of the screw 4 away from the axis of the annular columnar iron core 3, and the proximal air channel 18b is on the side of the screw 4 close to the axis of the annular columnar iron core 3. The front ends of both the distal air channel 18a and the proximal air channel 18b are connected to the nut chamber 35.

[0040] The principle of the second embodiment:

[0041] When the permanent magnet rotor, based on the structure of the "Second Embodiment," rotates at high speed around the axis of the annular cylindrical iron core 3 as a whole, the air pressure is lower closer to the axis of the annular cylindrical iron core 3 in the relatively enclosed space within the nut chamber 35. Consequently, the air pressure at the connection between the near-center air duct 18b and the nut chamber 35 is lower than the air pressure at the connection between the far-center air duct 18a and the nut chamber 35. Therefore, under the action of the air pressure difference, the following "internal gas circulation" is formed: the rear end of the near-center air duct 18b continuously draws away the air at the rear end of the stator and rotor chambers, and the air drawn into the near-center air duct 18b continuously flows forward into the nut chamber 35. Meanwhile, the air flowing into the nut chamber 35 continuously flows into the front end of the far-center air duct 18a and enters the far-center air duct 18a. The gas is eventually discharged back to the rear end of the stator and rotor cavity. During the aforementioned "gas internal circulation" process, the gas continuously carries away heat from the interior of the annular core 3 as it flows through the near-center air duct 18b and the far-center air duct 18a, preventing the annular core 3 from overheating. Simultaneously, in the structure of the "second embodiment," the nut chamber 35 serves as an essential intermediate cooling station for the "gas internal circulation." As the gas flows through the nut chamber 35, the heat-conducting metal transmission ring 11 with heat dissipation fins on its surface provides mid-course heat dissipation for the gas that has already absorbed heat once, alleviating the problem of reduced heat absorption efficiency caused by excessively high initial gas temperature during the flow through the far-center air duct 18a. High-efficiency thermal management is achieved through the combined cooling of the pressure difference and the heat-conducting transmission ring. The heat dissipation fins of the transmission ring 11 enhance convective heat transfer, improving cooling efficiency and making it suitable for high-power-density motors.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A permanent magnet motor rotor, characterized in that: It includes a ring-shaped iron core (3) made of several thin silicon steel sheets stacked together; a magnetic steel channel (31) extending along the axial direction is passed through the ring-shaped iron core (3) near the outer peripheral surface; a front ring (6) and a rear ring (1) are tightly attached to the front and rear ends of the ring-shaped iron core (3); the front ring (6) and the rear ring (1) respectively block the front and rear ends of each magnetic steel channel (31); The combined structure formed by the annular columnar iron core (3) and the rear end ring (1) has a threaded passage (51) extending along the axial direction, and a threaded passage (4) passes through the threaded passage (51). The screw (4) is threaded with a nut (21) at the rear end, and the nut (21) presses against the outer end face of the rear end ring (1) through the anti-loosening washer assembly (20); The screw (4) has a threaded connection with a b nut (17) and a c nut (13) at the front end. The b nut (17) is closer to the annular core (3) than the c nut (13). The b nut (17) presses against the front end face of the annular core (3) through the b anti-loosening washer assembly (22). The front end ring (6) has a nut sleeve (16) cut out, and a b nut (17) is fitted inside the nut sleeve (16). An annular space is formed between the outer periphery of the b nut (17) and the inner ring of the nut sleeve (16). A force transmission ring (11) is coaxially located on the outer side of the nut sleeve (16). The area enclosed by the force transmission ring (11) is the nut chamber (35). The nut (17) is located in the nut chamber (35). Each force transmission ring (11) has a disc-shaped washer (12) coaxially attached to the side away from the front end ring (6). The nut (13) presses the disc-shaped washer (12) away from the force transmission ring (11) through the anti-loosening washer assembly (14). The pushing force of the nut (13) is transmitted to the front end ring (6) through the force transmission ring (11), so that the front end ring (6) fits tightly against the annular columnar iron core (3).

2. A permanent magnet motor rotor according to claim 1, characterized in that: Both nut b (17) and nut c (13) ultimately transmit pressure to the front end of the annular core (3). Before the process of inserting the magnet channel (31) into the permanent magnet unit (2), nut a (21) and nut b (17) are both in a tightened state. After disassembling each nut c (13) and removing the front end ring (6), the magnet channel (31) at the front end of the annular core (3) in a stable state is exposed and connected to the outside.

3. A permanent magnet motor rotor according to claim 2, characterized in that: Each magnet channel (31) contains several adjacent permanent magnet units (2) arranged in an array along its length.

4. A permanent magnet motor rotor according to claim 3, characterized in that: Each force transmission ring (11) has a partial hollowed-out opening (15), and the opening (15) is located on each force transmission ring (11) at the position furthest from the axis of the annular columnar iron core (3); the nut chamber (35) is connected to the outside through the opening (15); the combined structure formed by the annular columnar iron core (3) and the rear end ring (1) has several air ducts (18) running through it along the axial direction, and the front end of each air duct (18) is connected to the nut chamber (35).

5. The assembly method of a permanent magnet motor rotor according to claim 4, characterized in that: During the assembly process, before finally tightening the c nut (13), the force transmission ring (11) needs to be rotated until the open ring notch (15) of the force transmission ring (11) is rotated to the position furthest away from the axis of the ring column iron core (3). After it is in place, tighten the c nut (13).

6. A permanent magnet motor rotor according to claim 3, characterized in that: Each force transmission ring (11) is a complete circular ring. The nut compartment (35) is surrounded and wrapped by the force transmission ring (11) with a complete circular structure. The force transmission ring (11) is made of heat-conducting metal and has heat-conducting fins on its inner and outer walls. The combined structure formed by the annular columnar iron core (3) and the rear end ring (1) has several distal air channels (18a) and several proximal air channels (18b) running through it along the axial direction. The distal air channel (18a) is on the side of the screw (4) away from the axis of the annular columnar iron core (3), and the proximal air channel (18b) is on the side of the screw (4) close to the axis of the annular columnar iron core (3). The front ends of the distal air channel (18a) and the proximal air channel (18b) are connected to the nut compartment (35).

7. A permanent magnet motor rotor according to claim 6, characterized in that: When the permanent magnet rotor rotates at high speed around the axis of the cylindrical iron core (3) as a whole, the air pressure at the connection between the near-center air duct (18b) and the nut chamber (35) is lower than the air pressure at the connection between the far-center air duct (18a) and the nut chamber (35). Therefore, under the action of the air pressure difference, the following "gas internal circulation" is formed: the rear end of the near-center air duct (18b) continuously draws away the air at the rear end of the stator and rotor chamber, and the gas drawn into the near-center air duct (18b) continuously flows forward into the nut chamber (35), while the air flowing into the nut chamber (35) continuously flows into the front end of the far-center air duct (18a). The gas entering the far-center air duct (18a) is finally discharged from the rear end back to the rear end of the stator and rotor chamber.

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