Direct-current brushless motor

Abstract

The invention relates to the technical field of motor devices, in particular to a direct-current brushless motor which comprises a base, a rotor is rotatably mounted at the upper end of the base, an output shaft used for transmitting mechanical power is fixedly connected to the upper end of the rotor, an inner supporting plate is fixedly mounted at the upper end of the base, and a center cylinder is fixedly clamped to the upper end of the inner supporting plate. A plurality of supporting shells are fixedly installed on the outer surface of the center cylinder and divided into three sets, a coil is wound on the outer surface of each set of supporting shells, cooling devices used for cooling the coils are arranged at the inner ends of the supporting shells, and cooling oil circularly flows in the supporting shells and directly absorbs heat generated by the coils. Heat is quickly transferred to the outside through the cooling pipe and the heat dissipation fins, the overall temperature of the coil and the motor is remarkably reduced, meanwhile, in the cooling oil circulation process, the heat dissipation fan in the rotor works cooperatively, efficient heat transfer is achieved through liquid cooling, the heat dissipation effect is enhanced through air flowing, and the service life of the motor is prolonged. And stable operation of the motor in a high-temperature environment is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of motor devices, and specifically to a brushless DC motor. Background Art

[0002] A brushless DC motor (BLDC) is a motor that uses electronic commutation instead of traditional mechanical commutation. Compared with a brushed DC motor, a brushless motor has higher efficiency, longer life, and lower maintenance costs. Its working principle is that an electronic controller (usually a three-phase inverter) sequentially energizes the stator windings to generate a rotating magnetic field, driving the permanent magnet on the rotor to rotate;

[0003] In a traditional brushed DC motor, the switching of the current direction is achieved through brushes and a commutator. However, the mechanical contact between the brushes and the commutator can cause wear, sparks, and noise, limiting the life and performance of the motor. The brushless motor eliminates these problems through electronic commutation, so it has gradually replaced the brushed motor in many application scenarios.

[0004] After retrieval, it is found that the prior art publication number is CN 115912747 A, which discloses a brushless DC motor, including a motor main body. A top plate is fixedly installed on the surface of the motor main body. An output shaft is arranged inside the motor main body. An air inlet pipe is fixedly installed on the inner wall of the top plate. One end of the air inlet pipe that penetrates and inserts into the motor main body is fixedly installed with a group of thin pipes. One end of the thin pipe away from the air inlet pipe is fixedly installed with a diffusion pipe. A group of spray holes are formed on the surface of the diffusion pipe. An air outlet cavity is formed on the inner wall of the motor main body. The dry air entering the spray pipe finally sprays out from the spray holes. In this scheme, after absorbing heat inside the motor main body, it leaves the motor main body along the air outlet cavity and enters the protective elastic block. The protective elastic block then expands to wrap the motor main body, preventing the housing from deforming due to external collision and knocking on the motor main body, achieving the effect of protecting the motor main body while dissipating heat.

[0005] Therefore, based on the above retrieval and in combination with the existing technology, the motor cooling systems of the prior art usually rely on single air cooling or simple liquid cooling, with low heat dissipation efficiency and difficult to effectively meet the heat dissipation requirements under high-load and high-temperature conditions. In addition, the existing cooling systems often have complex structures, occupy a large space, and are difficult to integrate into the motor interior, resulting in an increase in the overall volume of the motor and an unsatisfactory heat dissipation effect, causing insufficient heat dissipation under high-load conditions or energy waste under low-load conditions. For this reason, we propose a brushless DC motor. Summary of the Invention

[0006] The purpose of the present invention is to provide a brushless DC motor to solve the problems raised in the above background art.

[0007] To achieve the above object, the present invention provides the following technical solutions: A brushless DC motor includes a base, a rotor is rotatably installed at the upper end of the base, and an output shaft for transmitting mechanical power is fixedly connected to the upper end of the rotor. An inner support plate is fixedly installed at the upper end of the base, a central cylinder is fixedly clamped at the upper end of the inner support plate, a plurality of support shells are fixedly installed on the outer surface of the central cylinder, and the support shells are arranged in a ring shape. A stator is fixedly installed at one end of the support shell away from the central cylinder. The plurality of support shells are divided into three groups, and coils are wound around the outer surfaces of each group of support shells. A cooling device for cooling the coils is provided at the inner end of the support shell. The inside of the central cylinder is filled with cooling oil, and a movable sleeve is provided inside. A high-temperature power-off device is arranged between the central cylinder and the inner support plate. When the temperature of the rotor is too high, the high-temperature power-off device can cut off the internal power supply to avoid damage to the device caused by high-temperature overload.

[0008] As a further aspect of the present invention, the cooling device is composed of a plurality of cooling pipes and auxiliary pipes. The cooling pipes and the auxiliary pipes are distributed in a ring shape and are arranged in an alternating manner. The cooling pipes and the auxiliary pipes are both arranged inside the support shell. A plurality of heat dissipation fins are fixedly installed inside the support shell, and the cooling pipes and the auxiliary pipes are both in close contact with the inside of the heat dissipation fins. Two adjacent cooling pipes are connected by a conduction pipe. The cooling pipes and the auxiliary pipes are distributed in a ring shape and are arranged in an alternating manner, increasing the contact area between the coolant and the heat dissipation fins, significantly improving the heat dissipation efficiency. The cooling pipes are in close contact with the heat dissipation fins, ensuring that heat can be quickly transferred to the coolant, further enhancing the heat dissipation effect.

[0009] As a further aspect of the present invention, a movable rod is arranged inside the inner end of the cooling pipe. The movable rod is a permanent magnet. After the coil on the outer surface of the support shell is energized, a magnetic field is generated inside the support shell. According to the direction of the magnetic field, the movable rod is subjected to an attractive force or a repulsive force and moves left and right inside the cooling pipe. The cooling pipe is communicated with the inside of the central cylinder, and the movable rod is rotatably connected to the movable sleeve through an auxiliary rod. A movable plug is sleeved on the outer surface of the movable rod, and a plurality of conduction grooves are opened on the outer surface of the movable rod, and the movable plug corresponds to the conduction grooves. The movable rod is a permanent magnet and can move left and right in the cooling pipe according to the change of the magnetic field (attractive force or repulsive force) inside the support shell, thereby automatically adjusting the flow direction and flow rate of the coolant and realizing dynamic cooling control.

[0010] As a further solution of the present invention, an evaporation pipe is penetrated through the inner end of the support shell. The evaporation pipe is located between two adjacent cooling pipes, and the input end of the evaporation pipe is fixedly connected to the output end of the conduction pipe. An evaporation sleeve is fixedly connected to the inner end of the evaporation pipe. The diameter of the center of the evaporation sleeve is smaller than the diameter of the center of the evaporation pipe. A plurality of balloons are fixedly installed at the inner end of the central cylinder. The balloons correspond to the auxiliary pipes and are fixedly communicated with them. The output end of the evaporation pipe is fixedly connected to a water outlet pipe, and the water outlet pipe is fixedly communicated with the balloons. The cooling oil output by the evaporation pipe then flows into the interior of the balloons from the water outlet pipe. The evaporation pipe is communicated with the cooling pipes, the conduction pipe, and the balloons to form a complete cooling oil circulation system, ensuring that the cooling oil can flow efficiently and absorb heat, thereby improving the overall heat dissipation efficiency.

[0011] As a further solution of the present invention, the high-temperature power-off device includes an isolation sleeve which is penetrated through the interior of the movable sleeve. Two movable pipes are provided at each of the upper and lower ends of the isolation sleeve. Two adjacent movable pipes are connected by a matching pipe. The movable pipe close to the isolation sleeve is fixedly connected to the isolation sleeve. The design of the isolation sleeve and the movable pipes can trigger a power-off mechanism when the temperature of the motor is too high, cut off the power supply in time, and prevent the motor from being damaged due to overheating, significantly improving the safety and reliability of the motor.

[0012] As a further solution of the present invention, sealing rubber covers are fixedly connected to both the upper and lower ends of the inner side of the movable sleeve, and the sealing rubber covers are fixedly connected to the outer surface of the movable pipe away from the isolation sleeve. A magnetic block is provided at the inner end of the isolation sleeve. The magnetic block is triangular. A matching rod is rotatably connected to each of the upper and lower ends of the magnetic block. Memory metal strips are penetrated through the interiors of the two movable pipes. The sealing rubber covers are fixedly connected to the outer surface of the movable pipes, ensuring the sealing performance inside the movable sleeve, preventing the leakage of the cooling oil, and improving the reliability and safety of the system.

[0013] As a further solution of the present invention, the memory metal strips are respectively located on the upper and lower sides of the magnetic block, and a sealing plug is penetrated through the inner end of the movable pipe. The sealing plug is located below the magnetic block. The upper end of the sealing plug is fixedly connected to the bottom end of the memory metal strip. The bottom end of the sealing plug is fixedly connected to a passive rod. The memory metal strips are located on the upper and lower sides of the magnetic block, can deform in a high-temperature environment, and transmit actions through the sealing plug and the passive rod, accurately responding to temperature changes and ensuring the reliability of the high-temperature power-off device.

[0014] As a further solution of the present invention, an unlocking shell is fixedly connected to the bottom end of the inner support plate. A trigger rod is rotatably installed at the left end of the inner side of the unlocking shell. Two trigger bumps are fixedly installed at the bottom end of the passive rod. The end of the trigger rod away from the unlocking shell is located between the two trigger bumps.

[0015] As a further solution of the present invention, an unlocking rod is inserted through the inner end of the unlocking shell. The unlocking rod is connected to the unlocking shell through a return spring, and the unlocking rod corresponds to the trigger rod. A power supply head is fixedly installed at the right end of the unlocking rod, and the power supply head contacts the coil joint contact. The corresponding design of the unlocking rod and the trigger rod can quickly trigger the power-off mechanism in case of high temperature or other abnormalities, cut off the power supply, and avoid damage to the motor due to overload or overheating, significantly improving the safety and reliability of the motor.

[0016] As a further solution of the present invention, a cooling fan is fixedly installed at the bottom end of the output shaft. The cooling fan is located inside the rotor. The bottom end of the inner support plate is fixedly installed with a cooling coil through a clamp, and the cooling coil is connected to the central cylinder through a plurality of connecting pipes.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. When the present invention works, the cooling oil circulates inside the support shell, directly absorbs the heat generated by the coil, and quickly transfers the heat to the outside through the cooling pipe and the heat dissipation fins, significantly reducing the overall temperature of the coil and the motor. At the same time, during the circulation of the cooling oil, the cooling fan inside the rotor works together, achieving efficient heat transfer through liquid cooling and enhancing the heat dissipation effect through air flow, ensuring the stable operation of the motor in a high-temperature environment;

[0019] 2. When the present invention works, when the motor is working under high load and high temperature conditions, through the synergistic effect of the shape memory alloy strip and the magnetic block, the high-temperature power-off device can quickly respond to temperature changes, ensure that the power-off operation is immediately executed when the temperature reaches the dangerous threshold, prevent the motor from overheating further, and at the same time, the automatic trigger mechanism of the high-temperature power-off device does not require manual intervention and can automatically cut off the power supply when the motor temperature is too high, ensuring the safety of the motor and the surrounding equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a DC brushless motor;

[0021] Figure 2 is a disassembled view of a DC brushless motor;

[0022] Figure 3 is a schematic structural diagram of the stator part;

[0023] Figure 4 is a schematic structural diagram of the stator and the support shell;

[0024] Figure 5 is a schematic structural diagram of the inside of the central cylinder;

[0025] Figure 6 is a diagram showing the positional relationship between the balloon and the support shell;

[0026] Figure 7 It is a schematic structural diagram of a cooling pipe and an evaporation pipe;

[0027] Figure 8 It is a schematic internal structure diagram of a cooling pipe and an evaporation pipe;

[0028] Figure 9 It is a schematic structural diagram of the connection part between an auxiliary pipe and a return pipe;

[0029] Figure 10 It is a schematic internal structure diagram of a movable sleeve;

[0030] Figure 11 It is a schematic internal structure diagram of an isolation sleeve;

[0031] Figure 12 It is a schematic internal structure diagram of an unlocking shell.

[0032] In the figure: 1, base; 2, rotor; 3, output shaft; 101, stator; 102, inner support plate; 103, heat dissipation winding pipe; 104, heat dissipation fan; 105, central cylinder; 106, communication pipe; 107, coil joint;

[0033] 201, unlocking shell; 202, power supply head; 203, return spring; 204, unlocking rod; 205, trigger rod;

[0034] 301, support shell; 302, auxiliary rod; 303, water outlet pipe; 304, balloon; 305, auxiliary pipe; 306, movable rod; 307, evaporation pipe; 308, cooling pipe; 309, heat dissipation fin; 310, conduction pipe; 311, movable plug; 312, conduction groove; 313, evaporation sleeve; 314, one-way valve; 315, return pipe;

[0035] 401, movable sleeve; 402, extrusion strip; 403, fitting pipe; 404, movable pipe; 405, isolation sleeve; 406, magnetic block; 407, fitting rod; 408, shape memory alloy strip; 409, sealing plug; 410, passive rod; 411, trigger bump; 412, sealing rubber cover. Detailed implementation manners

[0036] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] Embodiment 1: Please refer to Figure 1 - Figure 4, a brushless DC motor, comprising a base 1, a rotor 2 is rotatably mounted on the upper end of the base 1, and an output shaft 3 for transmitting mechanical power is fixedly welded to the upper end of the rotor 2. A plurality of permanent magnets are fixedly connected to the inner end of the rotor 2 and are arranged in a ring. An inner support plate 102 is fixedly welded to the upper end of the base 1. A central cylinder 105 is fixedly clamped to the upper end of the inner support plate 102. A plurality of support shells 301 are fixedly mounted on the outer surface of the central cylinder 105 and are arranged in a ring. A stator 101 is fixedly mounted at one end of the support shell 301 away from the central cylinder 105. Both the stator 101 and the support shell 301 are made of metal. The plurality of support shells 301 are divided into three groups, and coils in different directions are wound around the outer surfaces of each group of support shells 301;

[0038] Specifically, a coil connector 107 is provided above the inner support plate 102. The input ends of the three groups of coils are fixedly connected to the coil connector 107. The coil connector 107 adopts a three-phase (U, V, W) structure, and the three-phase windings are energized in sequence (for example: U→V→W→U...), circulating repeatedly. Each time when energized, the magnetic field generated by the coil will attract the permanent magnets on the rotor 2, causing the rotor 2 to rotate. As the energization sequence changes, the magnetic force direction of the winding also changes, pushing the rotor 2 to rotate continuously, and then driving the output shaft 3 to rotate;

[0039] A cooling device for cooling the coil is provided at the inner end of the support shell 301. The inside of the central cylinder 105 is filled with cooling oil, usually synthetic oil, and a movable sleeve 401 is arranged inside. A high-temperature power-off device is arranged between the central cylinder 105 and the inner support plate 102. When the temperature of the rotor 2 is too high, the high-temperature power-off device can cut off the internal power supply to avoid damage to the device caused by high-temperature overload.

[0040] Please refer to Figure 3 、 Figure 5 - Figure 8 , the cooling device is composed of a plurality of cooling pipes 308 and auxiliary pipes 305. The cooling pipes 308 and the auxiliary pipes 305 are distributed in a ring and are arranged alternately with each other. Among them, both the cooling pipes 308 and the auxiliary pipes 305 are made of metal. The cooling pipes 308 and the auxiliary pipes 305 are both arranged inside the support shell 301. A plurality of heat dissipation fins 309 are fixedly mounted inside the support shell 301. The heat dissipation fins 309 are made of metal, and both the cooling pipes 308 and the auxiliary pipes 305 are in close contact with the inside of the heat dissipation fins 309. Two adjacent cooling pipes 308 are connected through a conduction pipe 310;

[0041] The inner end of the cooling pipe 308 is provided with a movable rod 306. The movable rod 306 is a permanent magnet with fixed magnetic poles (N pole and S pole), which interacts with the magnetic field generated by the coil. After the coil on the outer surface of the support shell 301 is energized, a magnetic field is generated inside the support shell 301. According to the direction of the magnetic field, the movable rod 306 is subjected to an attractive force or a repulsive force and moves left and right inside the cooling pipe 308. The cooling pipe 308 is internally connected to the central cylinder 105, so that the cooling oil inside the central cylinder 105 can flow into the inside of the cooling pipe 308. And the movable rod 306 is rotatably connected to the movable sleeve 401 through an auxiliary rod 302 (as Figure 5 shown), a movable plug 311 is sleeved on the outer surface of the movable rod 306, a sealing rubber ring is sleeved on the outer surface of the movable plug 311, and it is in close fit with the inner wall of the cooling pipe 308 to increase the sealing performance. A plurality of conduction grooves 312 are formed on the outer surface of the movable rod 306. The conduction grooves 312 are arranged in a ring shape, and the movable plug 311 corresponds to the conduction grooves 312. Specifically, a limiting ring is fixedly installed on the outer surface of the movable rod 306. The limiting ring is located on the left side of the movable plug 311, and a limiting block is fixedly welded at the junction of each conduction groove 312. The limiting block is located on the right side of the movable plug 311;

[0042] More specifically, when the movable plug 311 moves to the left and contacts the limiting ring, the conduction grooves 312 are completely exposed on the right side of the movable plug 311. When the movable plug 311 moves to the right and contacts the limiting block, at this time, the conduction grooves 312 communicate the two chambers on the left and right sides of the movable plug 311. Therefore, when the movable rod 306 moves to the left, the cooling oil enters the inside of the cooling pipe 308. When the movable rod 306 moves to the right, the movable plug 311 squeezes the cooling oil in the cavity of the cooling pipe 308 under the action of the limiting ring and flows into the conduction pipe 310;

[0043] As Figure 7 、 Figure 8 shown, an evaporation pipe 307 is penetrated through the inner end of the support shell 301. The evaporation pipe 307 is located between two adjacent cooling pipes 308, and the input end of the evaporation pipe 307 is fixedly connected to the output end of the conduction pipe 310. An evaporation sleeve 313 is fixedly welded to the inner end of the evaporation pipe 307. Specifically, the evaporation sleeve 313 is in a shape of an hourglass. The left and right ends of the evaporation sleeve 313 are fixedly welded to the inner wall of the evaporation pipe 307. The diameter of the center of the evaporation sleeve 313 is smaller than the diameter of the center of the evaporation pipe 307. When the cooling oil flows from the right side to the left side of the evaporation sleeve 313, due to the smaller diameter of the center of the evaporation sleeve 313, after the cooling oil flows to the left side, it will be atomized. At this time, according to Newton's law of cooling (the law followed when an object with a temperature higher than the surrounding environment transfers heat to the surrounding medium and gradually cools), the temperature will drop rapidly;

[0044] As Figure 2 、 Figure 5 -Figure 9 As shown, a plurality of balloons 304 are fixedly installed at the inner end of the central cylinder 105. The balloons 304 correspond to the auxiliary pipes 305 and are fixedly connected thereto. The output end of the evaporation pipe 307 is fixedly connected to a water outlet pipe 303, and the water outlet pipe 303 is fixedly connected to the balloons 304. The cooling oil output from the evaporation pipe 307 then flows into the interior of the balloons 304 from the water outlet pipe 303. The input end of the auxiliary pipe 305 is fixedly connected to a one-way valve 314. When the balloons 304 are squeezed, the liquid inside the balloons 304 enters the interior of the auxiliary pipe 305 through the one-way valve 314, while the liquid inside the auxiliary pipe 305 cannot flow back into the interior of the balloons 304. And the auxiliary pipes 305 are connected through a return pipe 315. A plurality of extrusion strips 402 are fixedly installed on the outer surface of the movable sleeve 401, and the extrusion strips 402 correspond to the balloons 304;

[0045] When the movable rod 306 moves to the right under the action of the coil magnetic force, the movable sleeve 401 is driven to move in the same direction as the movable rod 306 through the auxiliary rod 302. At this time, the extrusion strips 402 on the outer surface of the movable sleeve 401 squeeze the balloons 304 to cause them to deform.

[0046] Example 2: Please refer to Figure 5 、 Figure 10 - Figure 12

[0047]

[0048] On the basis of Example 1, a DC brushless motor, the high-temperature power-off device includes an isolation sleeve 405. The isolation sleeve 405 is sleeved inside the movable sleeve 401. Two movable pipes 404 are provided at each of the upper and lower ends of the isolation sleeve 405. The adjacent two movable pipes 404 are connected through a mating pipe 403. The movable pipe 404 close to the isolation sleeve 405 is fixedly connected to the isolation sleeve 405. The mating pipe 403 is made of soft silicone material, while the movable pipe 404 and the isolation sleeve 405 are both made of hard silicone material. Among them, a plurality of through holes are provided on the outer surface of the movable pipe 404 far from the isolation sleeve 405 and the outer surface of the movable sleeve 401, so that the cooling oil can penetrate into the interior of the isolation sleeve 405 through the through holes;

[0048] The movable pipe 404 located at the upper inner side of the movable sleeve 401 is rotatably connected to the upper inner side of the rotor 2 to provide a stable fulcrum, and the movable pipe 404 located at the lower inner side of the movable sleeve 401 is fixedly connected to the central cylinder 105.Sealing rubber caps 412 are fixedly connected to both the upper and lower ends of the inner side of the movable sleeve 401, and the sealing rubber caps 412 are fixedly connected to the outer surface of the movable tube 404 away from the isolation sleeve 405. Specifically, the sealing rubber caps 412 are made of soft silicone material and have elasticity to ensure that the movable sleeve 401 will not affect the isolation sleeve 405 during the process of being pulled by the movable rod 306. A magnetic block 406 is provided at the inner end of the isolation sleeve 405. The magnetic block 406 is triangular, and the edges and corners are rounded to avoid scratching the inner wall of the isolation sleeve 405 during rotation. Both the upper and lower ends of the magnetic block 406 are rotatably connected to a mating rod 407 through a rotating shaft. Memory metal strips 408 are respectively disposed inside the two movable tubes 404, and the memory metal strips 408 are respectively located on the upper and lower sides of the magnetic block 406. Specifically, the memory metal strips 408 are deformed in a high-temperature environment and return to the initial state after the environmental temperature drops. A sealing plug 409 is inserted into the inner end of the movable tube 404. The sealing plug 409 is located below the magnetic block 406. A sealing rubber ring is sleeved on the outer surface of the sealing plug 409 and is closely attached to the inner wall of the movable tube 404 to increase the sealing performance. More specifically, a limiting ring is fixedly installed at the inner end of the movable tube 404. The limiting ring is located above the sealing plug 409 to limit the upward movement distance of the sealing plug 409;

[0049] As Figure 3 , Figure 11 , Figure 12 shown, the upper end of the sealing plug 409 is fixedly welded to the bottom end of the memory metal strip 408. The memory metal strip 408 located above the magnetic block 406 is fixedly welded to the upper inner side of the movable tube 404. The bottom end of the sealing plug 409 is fixedly connected to a passive rod 410 through a bolt. The bottom end of the inner support plate 102 is fixedly connected to an unlocking shell 201 through a bolt. A trigger rod 205 is rotatably installed at the left inner side of the unlocking shell 201. Two trigger protrusions 411 are fixedly installed at the bottom end of the passive rod 410. The end of the trigger rod 205 away from the unlocking shell 201 is located between the two trigger protrusions 411;

[0050] Specifically, the connection between the two trigger protrusions 411 is arc-shaped. The trigger rod 205 located between the two trigger protrusions 411 is arc-shaped. When the trigger protrusions 411 move upward or downward, they will squeeze the trigger rod 205 to cause it to deflect, and the trigger rod 205 is snap-connected to the unlocking shell 201 through a reset torsion spring;

[0051] The inner end of the unlocking housing 201 is penetrated by an unlocking rod 204. The unlocking rod 204 is connected to the unlocking housing 201 by a return spring 203, and the unlocking rod 204 corresponds to the trigger rod 205. Specifically, triangular blocks are fixedly installed at the right end of the trigger rod 205 and the left end of the unlocking rod 204, and the two triangular blocks are engaged with each other. A power supply head 202 is fixedly installed at the right end of the unlocking rod 204, and the power supply head 202 is in contact with the coil connector 107 in a point-contact manner. When the trigger rod 205 deflects, the two engaged triangular blocks are disengaged from each other. At this time, under the elastic force of the return spring 203, the unlocking rod 204 drives the power supply head 202 to move and no longer connects to the coil connector 107, stopping the power supply to the coil.

[0052] As Figure 2 , Figure 3 , Figure 9 shown, a cooling fan 104 is fixedly installed at the bottom end of the output shaft 3. The cooling fan 104 is located inside the rotor 2. Ventilation openings are provided on the upper end of the rotor 2, the inner support plate 102, and the outer surface of the base 1. When the output shaft 3 rotates, the rotation of the cooling fan 104 is utilized to make the internal air flow, increasing the cooling efficiency. The bottom end of the inner support plate 102 is fixedly installed with a heat dissipation coil 103 through a clamp. The heat dissipation coil 103 is made of a metal material, making the heat transfer efficiency higher. The heat dissipation coil 103 is connected to the central cylinder 105 through a plurality of connecting pipes 106, and the return pipe 315 inside the support housing 301 is communicated with some of the connecting pipes 106.

[0053] The working principle of the present invention is:

[0054] During operation, a current starts to circulate through the winding on the outer surface of the support housing 301, magnetizing the support housing 301 and the stator 101. The magnetic field generated by the coil attracts the permanent magnet on the rotor 2, causing the rotor 2 to rotate. As the energization sequence changes, the magnetic force direction of the winding also changes, pushing the rotor 2 to continuously rotate, thereby driving the output shaft 3 to rotate, and the cooling fan 104 also starts to rotate, accelerating the air flow inside the rotor 2;

[0055] Meanwhile, when the internal movable rod 306 moves to the right under the attraction of the coil magnetic force, as the movable rod 306 moves to the right, the movable plug 311 squeezes the cooling oil in the cavity of the cooling pipe 308 under the action of the limiting ring to flow into the inside of the conduction pipe 310. At the same time, the auxiliary rod 302 drives the movable sleeve 401 to move in the same direction as the movable rod 306. At this time, the extrusion strip 402 on the outer surface of the movable sleeve 401 squeezes the balloon 304 to deform it. The opposite movable rod 306 moves to the right due to the movement of the movable sleeve 401 to the right, and the auxiliary rod 302 pulls the movable rod 306 to move to the right. Relatively, during the process of the current pulled movable rod 306 moving to the right, when the movable plug 311 moves to the left and contacts the limiting ring, the conduction groove 312 is completely exposed on the right side of the movable plug 311, allowing the cooling oil to enter the inside of the cooling pipe 308;

[0056] The deformed balloon 304 squeezes the internal cooling oil into the inside of the auxiliary pipe 305 and finally flows into the inside of the heat dissipation coiled pipe 103 along the return pipe 315. The air on the outer surface of the heat dissipation coiled pipe 103 is constantly flowing, so a certain heat dissipation effect is obtained;

[0057] Due to the continuous change of the magnetic field of the multiple support shells 301, the magnetic force block 406 inside the isolation sleeve 405 rotates with the change of the magnetic field. If the motor is overloaded, the temperature inside the rotor 2 continues to rise, making the temperature of the cooling oil inside the central cylinder 105 higher and higher, causing the shape memory metal strip 408 to deform when heated. At this time, the steadily rotating magnetic force block 406 vibrates. While the shape memory metal strip 408 deforms, it pulls the sealing plug 409 upward. Also, because the magnetic force block 406 vibrates at this time, the passive rod 410 moves upward or downward at this time, driving the trigger rod 205 to deflect through the trigger bump 411. The two mutually engaged triangular blocks are separated from each other. At this time, the unlocking rod 204 moves under the elastic force of the return spring 203, causing the unlocking rod 204 to drive the power supply head 202 to move and no longer connect to the coil connector 107, stopping the power supply to the coil, thereby realizing the emergency disconnection of the power supply to the motor and preventing the motor from being burned out by the heat generated by long-term overload. If the power supply is restored, with the help of repair tools, push the power supply head 202 so that the trigger rod 205 and the unlocking rod 204 are restored to connection.

[0058] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A brushless DC motor, comprising a base, characterized in that: A rotor is rotatably mounted on the upper end of the base, and an output shaft for transmitting mechanical power is fixedly connected to the upper end of the rotor, an inner support plate is fixedly mounted on the upper end of the base, a center tube is fixedly clamped on the upper end of the inner support plate, a plurality of support shells are fixedly mounted on the outer surface of the center tube, and the support shells are arranged in a ring shape, a stator is fixedly mounted on one end of the support shell away from the center tube, the plurality of support shells are divided into three groups, coils in different directions are wound on the outer surface of each group of support shells, a cooling device for cooling the coil is provided at the inner end of the support shell, the interior of the center tube is filled with cooling oil, and a movable sleeve is passed through the interior, and a high-temperature power-off device is provided between the center tube and the inner support plate.

2. A brushless DC motor according to claim 1, characterized in that: The cooling device is composed of a plurality of cooling tubes and auxiliary tubes, which are distributed in a ring shape and arranged alternately with each other. The cooling tubes and the auxiliary tubes are both passed through the interior of a supporting shell, and a plurality of heat dissipation fins are fixedly installed inside the supporting shell. The cooling tubes and the auxiliary tubes are both tightly fitted to the interior of the heat dissipation fins, and two adjacent cooling tubes are connected by a conducting tube.

3. A brushless DC motor according to claim 2, characterized in that: A movable rod is passed through the inner end of the cooling tube, and the movable rod is a permanent magnet. When the coil on the outer surface of the supporting shell is energized, a magnetic field is generated inside the supporting shell. According to the direction of the magnetic field, the movable rod is subjected to attractive or repulsive force and moves left and right inside the cooling tube. The cooling tube is connected to the interior of the central tube, and the movable rod and the movable sleeve are rotatably connected by an auxiliary rod. A movable plug is sleeved on the outer surface of the movable rod, and a plurality of conducting grooves are opened on the outer surface of the movable rod, and the movable plug corresponds to the conducting grooves.

4. A brushless DC motor according to claim 3, characterized in that: An evaporation tube is passed through the inner end of the support shell, and the evaporation tube is located between two adjacent cooling tubes. The input end of the evaporation tube is fixedly connected to the output end of the conducting tube. An evaporation sleeve is fixedly connected to the inner end of the evaporation tube, and the center diameter of the evaporation sleeve at the center is smaller than the center diameter of the evaporation tube.

5. A brushless DC motor according to claim 1, characterized in that: The high-temperature power-off device includes an isolation sleeve, which is inserted into the inside of the movable sleeve. Two movable tubes are respectively arranged at the upper and lower ends of the isolation sleeve. Two adjacent movable tubes are connected by a matching tube, and the movable tube close to the isolation sleeve is fixedly connected to the isolation sleeve.

6. A brushless DC motor according to claim 5, characterized in that: The upper and lower ends of the inner side of the movable sleeve are fixedly connected with a sealing cover, and the sealing cover is fixedly connected to the outer surface of the movable tube away from the isolation sleeve. The inner end of the isolation sleeve is provided with a magnetic block, and the magnetic block is triangular in shape. The upper and lower ends of the magnetic block are rotatably connected with matching rods, and memory metal strips are passed through the interior of the two movable tubes.

7. A brushless DC motor according to claim 6, characterized in that: The memory metal strips are respectively located on the upper and lower sides of the magnetic block, and a sealing plug is passed through the inner end of the movable tube. The sealing plug is located below the magnetic block, the upper end of the sealing plug is fixedly connected to the bottom end of the memory metal strip, and the bottom end of the sealing plug is fixedly connected to a passive rod.

8. A brushless DC motor according to claim 7, characterized in that: The bottom end of the inner support plate is fixedly connected with an unlocking shell, the inner left end of the unlocking shell is rotatably mounted with a trigger rod, the bottom end of the passive rod is fixedly mounted with two triggering protrusions, and one end of the trigger rod away from the unlocking shell is located between the two triggering protrusions.

9. A brushless DC motor according to claim 8, characterized in that: An unlocking rod is provided at the inner end of the unlocking shell, the unlocking rod is connected to the unlocking shell by a reset spring, and the unlocking rod corresponds to the trigger rod. A power supply head is fixedly installed at the right end of the unlocking rod, and the power supply head is in contact with the coil connector contact.

10. A brushless DC motor according to claim 1, characterized in that: A heat dissipation fan is fixedly installed at the bottom end of the output shaft, and the heat dissipation fan is located inside the rotor. A heat dissipation coil is fixedly installed at the bottom end of the inner support plate through a clamp, and the heat dissipation coil is connected to the central tube through a plurality of connecting pipes.

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