A rotor heat dissipation structure for a low-speed permanent magnet direct drive motor

Abstract

This utility model relates to a low-speed permanent magnet direct drive motor for belt conveyors and transport machines, specifically a rotor heat dissipation structure for a low-speed permanent magnet direct drive motor. It solves the technical problems of current low-speed permanent magnet direct drive motors using complex heat dissipation structures with internal cooling oil sprayed into hollow shafts, and the low speed and small airflow of fans mounted on the shaft. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor includes a stator, a magnetic pole core, a shaft, a drive end cover, and a non-drive end cover. The magnetic pole core is fixed to the shaft by a rotor bracket. The rotor heat dissipation structure includes multiple fan ribs fixed to both sides of the rotor bracket. The fan ribs on both sides of the rotor bracket are paired and evenly distributed around the shaft, with the outer length of the fan ribs longer than the inner length.

Description

Technical Field

[0001] This utility model relates to a low-speed permanent magnet direct drive motor for belt conveyors and transport machines, specifically a rotor heat dissipation structure for a low-speed permanent magnet direct drive motor. Background Technology

[0002] Low-speed permanent magnet direct drive motors are characterized by large diameter and short length. To reduce rotor weight and waste of silicon steel and shaft materials, a support structure is required for rotor assembly. Existing rotor support structures for low-speed permanent magnet direct drive motors are simple and only provide support. If the rotor core temperature becomes too high, it will be difficult to dissipate through the support, which may eventually lead to demagnetization of the permanent magnets due to high temperature, causing motor failure.

[0003] Existing rotor cooling solutions include those that spray cooling oil inside a hollow shaft and those that install a fan on the shaft. The latter uses a composite central shaft with an additional oil cooling system connected to one end. The centrifugal force generated by the rotor's high-speed rotation sprays cooling oil from inside the shaft onto the rotor, which then flows out through an outer loop. However, this cooling solution is costly due to the complex shaft structure and the need for an additional oil cooling system. Furthermore, the dynamic connection between the rotating shaft and the oil cooling system during operation raises concerns about sealing and reliability. Using this cooling structure, which relies on the centrifugal force generated by the rotor's high-speed rotation to spray the oil, is difficult to implement for low-speed permanent magnet direct-drive motors.

[0004] Existing solutions employ a fan mounted on a rotor shaft. The high-speed rotation of the rotor drives the fan, and the airflow generated by the fan passes through the air gap between the stator and rotor, or through the stator ventilation holes, and the gap between the rotor and the end cover, ultimately forming a loop through the rotor ventilation holes. During this airflow, heat is carried away from the rotor and dissipated through the end cover and the frame. However, this shaft-mounted fan design requires the rotor's high-speed rotation to drive the fan and generate airflow. For low-speed permanent magnet direct-drive motors, the low rotor speed results in low airflow from the shaft-mounted fan, offering minimal cooling effect and making effective heat dissipation difficult. Furthermore, the shaft-mounted fan structure requires an airflow loop through the stator. For permanent magnet motors, the stator temperature is much higher than the rotor temperature; during airflow, heat from the stator may be carried to the rotor, causing the rotor temperature to rise. Utility Model Content

[0005] This invention addresses the technical problems of complex heat dissipation structures in current low-speed permanent magnet direct drive motors that use hollow shafts with internal cooling oil spraying, and the low speed and small air volume of fans mounted on the shafts. It provides a rotor heat dissipation structure for low-speed permanent magnet direct drive motors.

[0006] This utility model is achieved by the following technical solution: a rotor heat dissipation structure for a low-speed permanent magnet direct drive motor, wherein the low-speed permanent magnet direct drive motor includes a stator, a magnetic pole core, a rotating shaft, a transmission end cover and a non-transmission end cover, and the magnetic pole core is fixed on the rotating shaft by a rotor bracket; the rotor heat dissipation structure includes multiple fan ribs fixed on both sides of the rotor bracket; the fan ribs located on both sides of the rotor bracket are paired and evenly distributed around the rotating shaft, and the outer length of the fan rib is longer than the inner length.

[0007] Furthermore, the rotor heat dissipation structure also includes multiple support ribs fixed on both sides of the rotor support. The support ribs on both sides of the rotor support are paired up and the support ribs on the same side are evenly distributed around the rotating shaft. The support ribs and fan ribs have different thicknesses and are distributed alternately. The outer length of the support ribs is longer than the inner length.

[0008] Furthermore, the rotor support includes an outer ring connected to the magnetic pole core, an inner ring connected to the rotating shaft, and a ring rib connecting the outer ring and the inner ring; the fan rib and the support rib are both connected to the ring rib, the outer ring, and the inner ring; the transmission end cap and the non-transmission end cap form two large unclosed air cavities on both sides of the ring rib, and each large air cavity is further divided into multiple small unclosed air cavities by the support rib and the fan rib on the same side.

[0009] Furthermore, the lengths of the support ribs and fan ribs along the height direction remain unchanged initially, and then a transition is achieved through changes in the circular arc structure.

[0010] Furthermore, the rotor heat dissipation structure also includes multiple fan plates evenly distributed at both ends of the magnetic pole core 2.

[0011] Furthermore, the fan plate includes a support plate connected to the end face of the magnetic pole core, a baffle plate mounted on top of the support plate, fan blades mounted on the outer side of the support plate, and a baffle plate connected to the fan blades; the fan blades are welded at an angle to form an angle of attack with the direction of rotation; the baffle plate is welded at an angle to the support plate to form a baffle angle.

[0012] Furthermore, the fan plate is fixed at a position close to the permanent magnet mounting position on the magnetic pole core.

[0013] Furthermore, the number of fan plates is the same as the number of permanent magnet poles.

[0014] Furthermore, the fan plate is bolted to the rotor pressure ring of the magnetic pole core.

[0015] Furthermore, the inner sides of the transmission end cap and the non-transmission end cap are designed with an outward radial arc angle according to the airflow direction.

[0016] The rotor support is welded with support ribs and fan ribs, combining the functions of rotor core fixation and fan; a fan plate is fixed on the rotor core, providing the fan function.

[0017] After the motor starts running, the rotor rotates, and the support ribs and fan ribs inside the rotor bracket drive the airflow. The outer sides of the support ribs and fan ribs are longer, and the flow space formed with the end cover is narrower. Combined with the higher linear velocity on the outer sides of the support ribs and fan ribs, a lower air pressure is formed than on the inner sides, thus generating air circulation. Air flows from the internal space of the rotor bracket along the outer ring of the bracket to the end cover, carrying the heat generated by the rotor core to the end cover. After being dissipated by the end cover, the air flows back to the internal space of the rotor bracket along the shaft, forming an air loop.

[0018] When the rotor rotates, the fan plate mounted on the rotor magnetic pole core rotates simultaneously. The fan plate utilizes the large diameter and high linear velocity of the permanent magnet direct drive motor rotor to generate radial airflow through centrifugal force. The air carries away the heat generated by the rotor core through the support plate, changes the airflow direction through the baffle plate to the end cover, dissipates heat through the end cover, and then flows back to the fan plate.

[0019] The support ribs combine the functions of support and fan. Both the fan ribs and the support ribs function as fans and complement each other.

[0020] The fan blades are welded at an angle to the direction of rotation, improving fan efficiency. The baffle plate and support plate are welded at an angle to create a baffle angle and adjust the airflow direction.

[0021] The beneficial effects of this utility model are as follows: This utility model overcomes the problem that traditional heat dissipation solutions cannot be implemented due to the low speed of low-speed permanent magnet direct drive motors. By welding support ribs and fan ribs inside the rotor bracket, the functions of rotor core fixation and fan are combined, simplifying the rotor structure and avoiding the complex and costly heat dissipation structure of spraying cooling oil inside the hollow shaft. A fan plate is installed on the rotor core pressure ring, utilizing the high linear velocity of the rotor's outer diameter to overcome the problem of low speed and low fan flow in low-speed direct drive permanent magnet motors. By installing a baffle plate on the fan plate, forming an airflow circuit with the end cover, the problem of stator temperature being transferred to the rotor during airflow is overcome. This effectively solves the rotor heat dissipation problem caused by the large rotor diameter and low speed of low-speed permanent magnet direct drive motors, reduces the risk of shutdown due to high-temperature demagnetization of permanent magnets, increases the reliability of low-speed permanent magnet direct drive motors, reduces the motor failure rate, and improves the working efficiency of belt conveyors and transport machines. Attached Figure Description

[0022] Figure 1 A cross-sectional view of the rotor heat dissipation structure of the low-speed permanent magnet direct drive motor described in this utility model.

[0023] Figure 2 Rotor heat dissipation structure rib layout diagram of low-speed permanent magnet direct drive motor ( Figure 1 (Side view).

[0024] Figure 3 Schematic diagram of the fan plate structure.

[0025] 1. Shaft; 2. Magnetic pole core; 3. Rotor support; 4. Support rib; 5. Fan rib; 6. Outer ring of support; 7. Inner ring of support; 8. Stator; 9. Drive end cover; 10. Non-drive end cover; 11. Fan plate; 12. Rotor pressure ring; 13. Ring rib; 14. Support plate; 15. Baffle top plate; 16. Fan blade; 17. Baffle outer plate. Detailed Implementation

[0026] It should be noted that the specific embodiments of this utility model described below are merely illustrative of its features, and their main purpose is to enable those skilled in the art to understand the content of this utility model, but they are not limited to the specific embodiments described below. Any modifications or changes made based on this utility model are within the scope of protection of this utility model.

[0027] Example 1: A rotor cooling structure for a low-speed permanent magnet direct drive motor includes a stator 8, a rotor support 3, a magnetic pole core 2, a shaft 1, a drive end cover 9, a non-drive end cover 10, and a fan plate 11. The shaft 1 is mounted on the stator 8 via the drive end cover 9 and the non-drive end cover 10. The magnetic pole core 2 is fixed to the shaft 1 via the rotor support 3. The rotor support 3 and the shaft 1 are connected by a keyway, and the rotor support 3 and the magnetic pole core 2 are fixedly connected by a rotor pressure ring 12 and bolts. The fan plate 11 is fixed to the magnetic pole core 2 by bolts.

[0028] Example 2: The rotor support 3 includes an outer ring 6, an inner ring 7, ring ribs 13, support ribs 4, and fan ribs 5. The ring ribs 13 are arranged between the outer ring 6 and the inner ring 7 and are connected by welding. Eight support ribs 4 are evenly welded to the inner side of the rotor support 3 to support and fix the outer ring 6 and the inner ring 7. Eight fan ribs 5 are evenly welded to the inner side of the rotor support 3, alternating with the support ribs 4. The number of support ribs 4 and fan ribs 5 can be adjusted according to the strength requirements of the rotor support.

[0029] Example 3: The inner ring 6 of the inner support 3, the inner ring 7 of the support, the ring rib 13, the shaft 1, the transmission end cover 9 and the non-transmission end cover 10 form two large unclosed air cavities on the left and right sides of the ring rib 13. Each large air cavity is divided into 16 small unclosed air cavities by the support rib 4 and the fan rib 5.

[0030] Example 3: The support rib 4 and fan rib 5 have the same structure but different thicknesses. The support rib 4 is 30mm thick, and the fan rib 5 is 5mm thick. The thickness can be adjusted according to the strength requirements of the rotor support. The outer length of the support rib 4 and fan rib 5 is longer than the inner length. The length along the height direction remains unchanged at first, and then changes in an arc shape.

[0031] Example 4: The air cavity inside the rotor support 3 is reduced in the radial direction so that the air pressure on the outside is lower than the air pressure on the inside when the rotor rotates. Based on fluid design analysis, the lengths of each section of the support rib 4 and the fan rib 5 are adjusted to achieve the best cooling effect.

[0032] Example 5: The fan plate 11 includes a support plate 14, a baffle top plate 15, fan blades 16, and a baffle outer plate 17.

[0033] Example 6: The fan blades 16 are welded at an angle to form an angle of attack with the direction of rotation, improving fan efficiency. Based on motor speed and fluid design analysis, the angle of attack can be adjusted to achieve optimal design results. The baffle plate 15 and the support plate 14 are welded at an angle to form a baffle angle, adjusting the airflow direction. Based on the end cover design structure, the baffle angle can be adjusted to achieve optimal cooling effect.

[0034] Example 7: The fan plate 11 is fixed at a position close to the permanent magnet installation position on the magnetic pole core 2 to achieve the best heat dissipation effect and maximum air volume. The number of fan plates 11 is the same as the number of permanent magnet poles.

[0035] Example 8: When the rotor rotates, the fan plate 11 mounted on the rotor magnetic pole 2 core rotates simultaneously, generating radial airflow through centrifugal force. The airflow is guided to the end cover by the baffle plate 15. The transmission end cover 9 and the non-transmission end cover 10 are designed with an arc angle according to the airflow direction.

[0036] In summary, the present invention has the following technical features:

[0037] 1. A rotor heat dissipation structure for a low-speed permanent magnet direct drive motor with two heat dissipation circuits, wherein the rotor support is the core component, which together with the shaft and end cover constitutes heat dissipation circuit one, and the fan plate is the core component, which together with the end cover and magnetic pole core constitutes heat dissipation circuit two.

[0038] 2. A rotor support that combines the functions of core fixing and fan, using curved ribs to combine support and fan functions, while increasing the alternating distribution of fan ribs and support ribs to improve fan function;

[0039] 3. A rotor heat dissipation structure in which a fan plate is installed near a permanent magnet, which improves the heat dissipation effect by utilizing the high linear velocity on one side of the rotor's outer diameter.

[0040] 4. A fan plate equipped with a wind deflector top plate, which improves the airflow circuit and prevents air from flowing through the stator.

Claims

1. A rotor heat dissipation structure for a low-speed permanent magnet direct drive motor, the low-speed permanent magnet direct drive motor comprising a stator (8), a magnetic pole core (2), a rotating shaft (1), a transmission end cover (9), and a non-transmission end cover (10), the magnetic pole core (2) being fixed to the rotating shaft (1) by a rotor bracket (3); characterized in that, The rotor heat dissipation structure includes multiple fan ribs (5) fixed on both sides of the rotor bracket (3); the fan ribs (5) located on both sides of the rotor bracket (3) are paired up and the fan ribs (5) located on the same side are evenly distributed around the rotating shaft (1), and the outer length of the fan ribs (5) is longer than the inner length.

2. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 1, characterized in that, The rotor heat dissipation structure also includes multiple support ribs (4) fixed on both sides of the rotor bracket (3). The support ribs (4) on both sides of the rotor bracket (3) are paired up and the support ribs (4) on the same side are evenly distributed around the rotating shaft (1). The support ribs (4) and the fan ribs (5) have different thicknesses and are distributed alternately. The outer length of the support ribs (4) is longer than the inner length.

3. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 2, characterized in that, The rotor support (3) includes an outer ring (6) connected to the magnetic pole core (2), an inner ring (7) connected to the shaft (1), and a ring rib (13) connecting the outer ring (6) and the inner ring (7); the fan rib (5) and the support rib (4) are connected to the ring rib (13), the outer ring (6) and the inner ring (7); the transmission end cap (9) and the non-transmission end cap (10) form two large unclosed air cavities on both sides of the ring rib (13), and each large air cavity is further divided into multiple small unclosed air cavities by the support rib (4) and the fan rib (5) on the same side.

4. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 2 or 3, characterized in that, The lengths of the support ribs (4) and fan ribs (5) along the height direction remain unchanged initially, and then transition is achieved by changing the arc structure.

5. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 1, characterized in that, The rotor heat dissipation structure also includes multiple fan plates (11) evenly distributed at both ends of the magnetic pole core (2).

6. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 5, characterized in that, The fan plate (11) includes a support plate (14) connected to the end face of the magnetic pole core (2), a baffle plate (15) installed on the top of the support plate (14), a fan blade (16) installed on the outer side of the support plate (14), and a baffle plate (17) connected to the fan blade (16); the fan blade (16) is welded at an angle to form an angle of attack with the direction of rotation; the baffle plate (15) is welded at an angle to the support plate (14) to form a baffle angle.

7. A rotor heat dissipation structure for a low-speed permanent magnet direct drive motor as described in claim 6, characterized in that, The fan plate (11) is fixed on the magnetic pole core (2) near the permanent magnet mounting position.

8. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 7, characterized in that, The number of fan plates (11) is the same as the number of permanent magnet poles.

9. The rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to claim 7, characterized in that, The fan plate (11) is bolted to the rotor pressure ring (12) of the magnetic pole core (2).

10. A rotor heat dissipation structure for a low-speed permanent magnet direct drive motor according to any one of claims 5-9, characterized in that, The inner sides of the transmission end cap (9) and the non-transmission end cap (10) are designed with an arc angle that extends radially outward according to the airflow direction.

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