A mixed water-cooled permanent magnet direct drive motor with a casing and stator slot

Abstract

This invention discloses a hybrid water-cooled permanent magnet direct drive motor with a housing and stator slots, belonging to the field of permanent magnet direct drive motor technology. It includes a housing, a stator assembly, and a rotor assembly. The housing has circumferentially arranged Z-shaped water channels for external cooling. The stator assembly includes a stator core module A, multiple stator core modules B, multiple shaped windings, multiple in-slot water-cooled copper tubes, end water distributors, and end water collectors. This invention achieves slot-free wedge fixing of the in-slot water-cooled copper tubes through a tenon joint between stator core modules A and B. The two ends of the in-slot water-cooled copper tubes are directly screwed to the end water distributors and end water collectors via copper ferrule rotary joints. The overall structure is simple and easy to install, avoiding the problems of bent and messy water pipes, installation difficulties, and interference with subsequent rotor assembly in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet direct drive motor technology, specifically to a water-cooled permanent magnet direct drive motor with a hybrid housing and stator slots. Background Technology

[0002] Low-speed, high-torque permanent magnet synchronous motors are widely used in heavy-duty applications such as ports and mines due to their advantages of high efficiency, high power factor, high torque density, and strong short-term overload capacity. Constrained by these application environments, these conditions place extremely high demands on the reliability and torque density of the drive motor.

[0003] Traditional low-speed, high-torque permanent magnet synchronous motors often employ internal water cooling systems within the motor housing. This method is simple in structure, technologically mature, and highly effective in small to medium power-level low-speed, high-torque permanent magnet motors. However, when this cooling method is applied to explosion-proof, megawatt-level low-speed, high-torque permanent magnet motors, severe heat accumulation occurs in the air gap between the stator and rotor, leading to deteriorated heat dissipation conditions for the rotor permanent magnets. This can easily cause irreversible demagnetization failures due to high temperatures in the permanent magnets, and this problem becomes increasingly prominent as the motor power level increases. Therefore, traditional housing-based water cooling methods are no longer sufficient to meet the application requirements of industries such as ports and mines for high-power, high-torque, and high-reliability low-speed, high-torque permanent magnet synchronous motors.

[0004] To address the aforementioned issues, some research has attempted to utilize the space within the stator slots to arrange cooling structures to reduce winding temperatures, as exemplified by patents CN112332568B and CN109494901B, both titled "Invention Patent for an In-Slot Water-Cooled Motor Stator." However, existing technologies exhibit several drawbacks. Firstly, the water pipes in current in-slot cooling solutions are often bent and disorganized, making installation difficult and impacting the assembly of subsequent rotor and other structures. Secondly, the excessive extension of the water pipes beyond the stator creates temperature gradients, affecting winding cooling performance and hindering sealing, thus compromising the motor's explosion-proof capabilities and making it difficult to balance heat dissipation efficiency with engineering reliability. Therefore, optimizing the heat dissipation of the rotor permanent magnets while ensuring explosion-proof performance is a key technical challenge for further improving the power rating and operational reliability of low-speed, high-torque permanent magnet motors. Summary of the Invention

[0005] To address the aforementioned shortcomings of the prior art, the present invention provides a hybrid water-cooled permanent magnet direct drive motor with a housing and stator slots, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a water-cooled permanent magnet direct drive motor with a hybrid housing and stator slots, comprising a housing, a stator component, and a rotor component. The housing is provided with circumferentially arranged Z-shaped water channels for external cooling. The stator component includes a stator core module A, multiple stator core modules B, multiple shaped windings, multiple in-slot water-cooled copper pipes, an end water distributor, and an end water collector. Multiple stator slots are evenly distributed in the inner ring of the stator core module A. The shaped windings are disposed on the stator core module A through the stator slots and are located at the bottom of the stator slots. The water-cooled copper tubes in the slot include a rectangular section within the water-cooled tube slot, a pair of bent ends of the water-cooled copper tubes, and a pair of rotary joints. The rectangular section within the water-cooled tube slot matches the shape of the stator slot opening and is positioned within the stator slot. Multiple stator core modules B are positioned within the inner ring of stator core module A and between every two stator slots. Each stator core module B radially locks the water-cooled copper tubes in adjacent slots. The bent ends of the pair of water-cooled copper tubes are located at both ends of the rectangular section within the water-cooled tube slot, with the bent ends bent outwards and one outer end connected to the rotary joint. The end water collector includes a water collector outlet, a water collector annular tube body, and multiple water collector external threaded tubes. The multiple water collector external threaded tubes are connected and positioned on one side of the water collector annular tube body, and the water collector... The number of externally threaded pipes is equal to the number of water-cooled copper pipes in the tank. The water outlet of the water collector is connected to the other side of the annular tube of the water collector. The end water divider includes a water distributor inlet, a water distributor annular tube, and multiple water distributor externally threaded pipes. The multiple water distributor externally threaded pipes are connected to one side of the water distributor annular tube, and the number of water distributor externally threaded pipes is equal to the number of water-cooled copper pipes in the tank. The water distributor inlet is connected to the other side of the water distributor annular tube. The water collector externally threaded pipe is connected to a rotary joint at one end of the water-cooled copper pipe in the tank, and the water distributor externally threaded pipe is connected to a rotary joint at the other end of the water-cooled copper pipe in the tank. The end water divider, the end water collector, the winding end, and the bent part of the water-cooled copper pipe end are potted with a high thermal conductivity potting compound with a thermal conductivity of 1.0 W / m·K.

[0007] Preferably, a dovetail groove is provided on the inner ring of the stator core module A and at the center of the two adjacent stator slots, and a dovetail bar is provided at the center of the side wall of the stator core module B, and the dovetail bar is interference-fitted into the dovetail groove.

[0008] Preferably, the stator core module B is made of grain-oriented silicon steel sheet by stamping.

[0009] Preferably, the rotary joint is a copper nanotube rotary joint.

[0010] Preferably, a sealing rubber gasket is provided inside the copper nanotube rotary joint.

[0011] Preferably, the rectangular portion inside the water-cooled pipe groove and the bent portions at the ends of the pair of water-cooled copper pipes are integrally formed.

[0012] Preferably, the end water collector and the end water distributor are made of stainless steel.

[0013] This invention provides a hybrid water-cooled permanent magnet direct-drive motor with both the housing and stator slots, which has the following advantages: 1. The present invention comprises a rectangular portion of the water-cooled copper tube in the slot that matches the shape of the stator slot opening and a bent portion at the end of the water-cooled copper tube that does not affect assembly. The water-cooled copper tube in the slot is fixed without slot wedges by tenon joint between stator core module A and stator core module B. The two ends of the water-cooled copper tube in the slot are directly screwed to the end water distributor and the end water collector through copper ferrule rotary joints. The overall structure is simple and easy to install, avoiding the problems of messy water pipe bending, difficult installation, and affecting subsequent rotor assembly in the prior art. 2. The stator core module A with dovetail slots and the stator core module B with dovetail bars in this invention have the following structures. The stator core module B is made of grain-oriented silicon steel sheet by stamping, which facilitates the installation of water-cooled copper pipes in the slot and the stator core module B. The grain-oriented silicon steel sheet material can avoid the end leakage magnetic path (tooth tip leakage magnetic path) of the stator core module B. In addition, the traditional slot wedge structure is omitted, and a gap is left between two adjacent stator core modules B, so that the water-cooled copper pipe at the stator slot can directly face the gap between the rotor component and the stator component, improve the cooling effect, and thus greatly reduce the temperature rise of the permanent magnet. 3. In this invention, the water-cooled copper pipes inside the tank are short in length and have a simple water path. Furthermore, the water-cooled copper pipes inside the tank adopt a parallel water path design with the water inlet and outlet directions opposite to the Z-shaped water channel around the casing, effectively avoiding a large temperature gradient along the motor axis. At the same time, the water-cooled copper pipes inside the tank are sealed to the end water distributor and the end water collector through a copper ferrule rotary joint and a sealing rubber gasket. The cooling medium circulates in the closed pipeline. The ends of the water-cooled copper pipes inside the tank are potted with a high thermal conductivity potting compound, further enhancing the sealing reliability. This overcomes the problems of existing solutions where excessively long water pipes affect the winding cooling performance and the inability to effectively seal leads to difficulty in ensuring explosion-proof performance. 4. This invention achieves simultaneous cooling from both the inner and outer sides through casing water cooling and in-slot water cooling. This significantly improves the heat dissipation conditions of the rotor permanent magnet without compromising the motor assembly or its explosion-proof sealing. This invention provides a practical and feasible technical solution for improving the power rating and operational reliability of low-speed, high-torque permanent magnet motors. Attached Figure Description

[0014] Figure 1 This is a topological diagram of a hybrid water-cooled permanent magnet direct drive motor in the housing and stator slots according to the present invention. Figure 2This is a structural diagram of the water-cooled copper tube inside the tank of the present invention; Figure 3 This is a structural diagram of the end water collector and end water distributor of the present invention; Figure 4 This is a structural diagram of the present invention before filling; Figure 5 This is a structural diagram of the entire structure of the present invention after potting; Figure 6 This is a temperature comparison chart of various components obtained based on Ansys fluid-structure interaction simulation software in this invention.

[0015] In the diagram: 1. Stator core module A; 2. Stator core module B; 3. Stator slot; 4. Molded winding; 5. Water-cooled copper tube inside the slot; 6. Dovetail slot; 7. Dovetail bar; 8. End water collector; 9. End water distributor; 10. High thermal conductivity potting compound; 51. Rectangular section inside the water-cooled tube slot; 52. Bent section at the end of the water-cooled copper tube; 53. Copper swivel joint; 81. Water collector outlet; 82. Water collector annular tube body; 83. Water collector external threaded tube; 91. Water distributor inlet; 92. Water distributor annular tube body; 93. Water distributor external threaded tube. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The present invention will now be described in detail through specific embodiments, as follows: According to the instruction manual Figures 1-6As can be seen, the present invention discloses a water-cooled permanent magnet direct-drive motor with a hybrid housing and stator slots, comprising a housing, a stator assembly, and a rotor assembly. The housing contains circumferentially arranged Z-shaped water channels for external cooling, which is existing technology and can be understood by those skilled in the art. The stator assembly includes a stator core module A1, multiple stator core modules B2, multiple shaped windings 4, multiple in-slot water-cooled copper pipes 5, an end water distributor 9, and an end water collector 8. Multiple stator slots 3 are evenly distributed within the inner ring of the stator core module A1. The shaped windings 4 are mounted on the stator core module A1 through the stator slots 3 and are located at the bottom of the stator slots 3; this design is also existing technology. The water-cooled copper tube 5 in the slot includes a rectangular portion 51 in the water-cooled tube slot, a pair of bent portions 52 at the ends of the water-cooled copper tubes, and a pair of rotary joints. The rectangular portion 51 in the water-cooled tube slot matches the shape of the stator slot 3 opening. Specifically, the shaped winding 4 is at the bottom of the stator slot 3, and the rectangular portion 51 in the water-cooled tube slot is near the opening of the stator slot 3. The shaped winding 4 and the rectangular portion 51 in the water-cooled tube slot fill the stator slot 3. Multiple stator core modules B2 are arranged in the inner ring of the stator core module A1 and located between every two stator slots 3. The distance between every two stator core modules B2 is less than the width of the stator slot 3, and each stator core module B2 radially locks the water-cooled copper tubes 5 in adjacent slots. Figure 1 As shown, both ends of the stator core module B2 extend into the stator slot 3, protruding slightly to secure the water-cooled copper tube 5 within the slot, preventing it from falling out. A gap is left between adjacent stator core modules B2, allowing the water-cooled copper tube at the stator slot 3 opening to directly face the gap between the rotor and stator components, improving cooling efficiency and significantly reducing the temperature rise of the permanent magnet. A pair of bent ends 52 of the water-cooled copper tubes are located at both ends of the rectangular portion 51 within the water-cooled tube slot. These bent ends 52 are bent outwards. To facilitate subsequent rotor installation, one outer end of the bent ends 52 connects to a rotary joint. The end face of the rotary joint is parallel to the end face of the motor, facilitating subsequent connection to the end water collector 8 and end water distributor 9. For example, during manufacturing, the bent ends 52 of the water-cooled copper tubes are first bent radially outwards by 60 degrees, and then axially bent by 60 degrees, forming a shape as shown. Figure 2 The state is shown. The end water collector 8 includes a water collector outlet 81, a water collector annular tube body 82, and multiple water collector external threaded tubes 83. The multiple water collector external threaded tubes 83 are connected and arranged on one side of the water collector annular tube body 82, which can be welded. The number of water collector external threaded tubes 83 is equal to the number of water-cooled copper tubes 5 in the tank. For subsequent installation, the water collector outlet 81 is connected and arranged on the other side of the water collector annular tube body 82. (As shown) Figure 3As shown, the end water distributor 9 includes a water distributor inlet 91, a water distributor annular tube body 92, and multiple water distributor external threaded pipes 93. The multiple water distributor external threaded pipes 93 are connected and arranged on one side of the water distributor annular tube body 92, which can be welded. The number of water distributor external threaded pipes 93 is equal to the number of water-cooled copper pipes 5 in the tank. For subsequent installation, the water distributor inlet 91 is connected and arranged on the other side of the water distributor annular tube body 92. The water collector external threaded pipe 83 is connected to a rotary joint at one end of the water-cooled copper pipe 5 in the tank, and the water distributor external threaded pipe 93 is connected to a rotary joint at the other end of the water-cooled copper pipe 5 in the tank. The rotary joint is a copper nub rotary joint 53, which is resistant to high pressure, vibration, and has good sealing effect. A sealing rubber gasket is installed inside the copper nub rotary joint 53 to further improve the sealing effect. Figure 4 and Figure 5 As shown in the comparison, the end water distributor 9, end water collector 8, winding ends, and the bent portion 52 of the water-cooled copper tube ends are potted with a high thermal conductivity potting compound 10 with a thermal conductivity of 1.0 W / m·K, further enhancing the sealing reliability. This overcomes the problems of existing solutions where excessive water pipe extension affects winding cooling performance and the inability to effectively seal leads to poor explosion-proof performance. The high thermal conductivity material can also cool the ends of the formed winding 4, improving the heat dissipation capacity of the formed winding 4. This invention achieves slotless wedge fixing of the water-cooled copper tube 5 in the slot through the tenon joint between the stator core module A1 and the stator core module B2. The two ends of the water-cooled copper tube 5 in the slot are directly screwed to the end water distributor 9 and the end water collector 8 through copper ferrule rotary joints 53. The overall structure is simple and easy to install, avoiding the problems of messy water pipe bending, difficult installation, and impact on subsequent rotor assembly in the prior art.

[0018] In this invention, the in-slot water-cooled copper pipe 5 is short and has a simple water path. Furthermore, the in-slot water-cooled copper pipe 5 adopts a parallel water path design with the water inlet and outlet directions opposite to the circumferential Z-shaped water channel of the motor housing, effectively avoiding a large temperature gradient along the motor axis. Simultaneously, the in-slot water-cooled copper pipe 5, the end water distributor 9, and the end water collector 8 are sealed together via a copper rotary joint 53 and a sealing rubber gasket. The cooling medium circulates within the closed pipe. The ends of the in-slot water-cooled copper pipe 5 are potted with a high thermal conductivity potting compound 10 (1.0 W / m·K), further enhancing sealing reliability. This overcomes the problems of existing solutions where excessively long water pipes affect winding cooling performance and the inability to effectively seal leads to poor explosion-proof performance.

[0019] Among them, a dovetail groove 6 is opened in the inner ring of the stator core module A1 and at the center of the two adjacent stator slots 3. A dovetail bar 7 is set at the center of the side wall of the stator core module B2. The dovetail bar 7 is inserted into the dovetail groove 6 with an interference fit, that is, it is connected by tenon and mortise. This facilitates the installation of the water-cooled copper pipe 5 in the slot and the stator core module B2, omitting the traditional slot wedge structure. A gap is left between the two adjacent stator core modules B2, so that the water-cooled copper pipe at the opening of the stator slot 3 can directly face the gap between the rotor component and the stator component, improve the cooling effect, and thus greatly reduce the temperature rise of the permanent magnet.

[0020] Among them, the stator core module B2 is made of oriented silicon steel sheet by stamping, which can avoid the end magnetic leakage circuit of the stator core module B2, that is, avoid the tooth tip magnetic leakage circuit.

[0021] Among them, the rectangular part 51 inside the water-cooled pipe groove and the bent part 52 at the end of a pair of water-cooled copper pipes are integrally molded, which improves the overall strength and sealing performance.

[0022] Among them, the end water collector 8 and the end water divider 9 are made of stainless steel, which is sturdy and durable.

[0023] For the same 300kW low-speed, high-torque motor, when using the traditional "casing water cooling" method and the hybrid cooling method of "casing water cooling + in-slot water cooling" proposed in this patent, the temperature comparisons of the motor stator, windings, permanent magnets, rotor, and air gap obtained based on Ansys fluid-structure interaction simulation software are as follows: Figure 6 As shown, the highest temperature of the air gap decreased by 46.6%, the highest temperature of the permanent magnet decreased by 41.8%, the highest temperature of the stator decreased by 36.4%, the highest temperature of the winding decreased by 0.5%, and the highest temperature of the rotor decreased by 41.7%. The combined cooling method of "casing water cooling + slot water cooling" has a significant effect.

[0024] The present invention achieves simultaneous cooling from both the inner and outer sides through casing water cooling and in-slot water cooling. This significantly improves the heat dissipation of the rotor permanent magnet without compromising the motor assembly or its explosion-proof sealing. The present invention provides a practical and feasible technical solution for improving the power rating and operational reliability of low-speed, high-torque permanent magnet motors.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hybrid water-cooled permanent magnet direct drive motor with a casing and stator slot, comprising a casing, a stator component and a rotor component, wherein Z-shaped water channels are arranged in the casing in a circumferential direction for outside cooling, characterized in that, The stator component includes a stator core module A (1), a plurality of stator core modules B (2), a plurality of shaped windings (4), a plurality of in-slot water-cooled copper pipes (5), an end part water collector (9) and an end part water collector (8), the inner circle of the stator core module A (1) is uniformly provided with a plurality of stator slots (3), the shaped windings (4) are arranged in the stator core module A (1) through the stator slots (3) and the shaped windings (4) are located at the bottom of the stator slots (3), the in-slot water-cooled copper pipe (5) includes an in-slot water-cooled copper pipe rectangular portion (51), a pair of water-cooled copper pipe end bending portions (52) and a pair of rotary joints, the in-slot water-cooled copper pipe rectangular portion (51) is matched with the shape of the slot opening of the stator slot (3) and is arranged in the stator slot (3), a plurality of stator core modules B (2) are arranged in the inner circle of the stator core module A (1) and are located between every two stator slots (3), and each stator core module B (2) radially clamps the adjacent two in-slot water-cooled copper pipes (5), a pair of water-cooled copper pipe end bending portions (52) are arranged at both ends of the in-slot water-cooled copper pipe rectangular portion (51), the water-cooled copper pipe end bending portion (52) is in a state of outwardly bending, and the outer end is connected with the rotary joint, the end part water collector (8) includes a water collector water outlet (81), a water collector annular pipe body (82) and a plurality of water collector external threaded pipes (83), the plurality of water collector external threaded pipes (83) are communicatively arranged on one side of the water collector annular pipe body (82), and the number of the water collector external threaded pipes (83) is equal to that of the in-slot water-cooled copper pipes (5), the water collector water outlet (81) is communicatively arranged on the other side of the water collector annular pipe body (82), the end part water collector (9) includes a water collector water inlet (91), a water collector annular pipe body (92) and a plurality of water collector external threaded pipes (93), the plurality of water collector external threaded pipes (93) are communicatively arranged on one side of the water collector annular pipe body (92), and the number of the water collector external threaded pipes (93) is equal to that of the in-slot water-cooled copper pipes (5), the water collector water inlet (91) is communicatively arranged on the other side of the water collector annular pipe body (92), the water collector external threaded pipe (83) is connected with the rotary joint at one end of the in-slot water-cooled copper pipe (5), and the water collector external threaded pipe (93) is connected with the rotary joint at the other end of the in-slot water-cooled copper pipe (5); the end part water collector (9), the end part water collector (8), the winding end part and the water-cooled copper pipe end bending portion (52) are filled with high-thermal-conductivity filling glue (10) with a thermal conductivity of 1.0 W / m·K.

2. The hybrid water-cooled permanent magnet direct drive motor with the stator slot and the casing according to claim 1, characterized in that, The inner circle of the stator core module A (1) and the positions corresponding to the centers of the adjacent two stator slots (3) are provided with dovetail grooves (6), and the side wall center positions of the stator core module B (2) are provided with dovetail strips (7), the dovetail strips (7) are inserted into the dovetail grooves (6) in interference.

3. The hybrid water-cooled permanent magnet direct drive motor with the stator slot and the casing according to claim 1, characterized in that, The stator core module B (2) is punched from oriented silicon steel sheets.

4. The hybrid water-cooled permanent magnet direct drive motor with the stator slot and the casing according to claim 1, characterized in that, The rotary joint is a copper nanometer rotary joint (53).

5. The hybrid water-cooled permanent magnet direct drive motor with the stator slot and the casing according to claim 4, characterized in that, The copper nanometer rotary joint (53) is provided with a rubber pad.

6. The hybrid water-cooled permanent magnet direct drive motor with the stator slot and the casing according to claim 1, characterized in that, The rectangular portion (51) inside the water-cooled pipe groove and the bent portions (52) at the ends of the pair of water-cooled copper pipes are integrally molded.

7. The hybrid water-cooled permanent magnet direct drive motor with the stator slot and the casing according to claim 1, characterized in that, The end water collector (8) and the end water distributor (9) are made of stainless steel.

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