Compact three-phase asynchronous motor

Abstract

The invention relates to the technical field of motors, in particular to a compact three-phase asynchronous motor. Comprising a motor body and a fan connected to the tail of the motor body. The fan is connected and driven by a main shaft at the tail part of the motor main body; the tail part of the motor main body is fixedly connected with a fan cover; one end, close to the tail of the motor body, of the fan cover is turned inwards; the inner side of the fan cover is slidably connected with a movable cover; the movable cover is connected with the inward turning position of one end of the fan cover through a first spring; the end face of the movable cover is provided with a second air inlet hole corresponding to the first air inlet hole in the fan cover. Under the driving of negative pressure generated by the continuously rotating fan, even if the first air inlet hole in the fan cover is blocked, external air can still enter the opened standby hole, enters the inner side of the movable cover along the standby hole and the second air inlet hole, and continuously rushes to the cooling fins under the driving of the fan, so that the cooling effect is improved. And the three-phase asynchronous motor can realize the purpose of continuous and efficient heat dissipation.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and specifically to a compact three-phase asynchronous motor. Background Art

[0002] A three-phase asynchronous motor is a common AC motor. It consists of a stator in the fixed part and a rotor in the rotating part. The working principle of this motor is based on the concept of a rotating magnetic field. The three-phase asynchronous motor has the characteristic of strong load adaptability, so a large amount of heat will be generated. In order to enable the three-phase asynchronous motor to take away more heat through the heat sink on the outer wall, a fan is generally installed at the tail of the three-phase asynchronous motor. The fan is driven by the main shaft to rotate, so that the wind enters through the air inlet of the fan cover, and finally blows towards the heat sink on the outer wall of the three-phase asynchronous motor, thereby accelerating the heat dissipation of the three-phase asynchronous motor.

[0003] In some relatively messy environments, if the air inlet of the fan cover at the tail of the three-phase asynchronous motor is blocked, the outside air cannot enter the inside of the fan cover along the air inlet of the fan cover, resulting in the rotation of the fan not being able to generate the wind blowing towards the heat sink, and then resulting in poor heat dissipation effect of the heat sink. When the maintenance personnel cannot arrive at the scene for maintenance in time, the temperature of the three-phase asynchronous motor rises rapidly, affecting the efficiency and even causing faults in the three-phase asynchronous motor.

[0004] In view of this, in order to overcome the above technical problems, the present invention proposes a compact three-phase asynchronous motor, which solves the above technical problems. Summary of the Invention

[0005] In order to make up for the deficiencies of the prior art, the present invention proposes a compact three-phase asynchronous motor. Driven by the negative pressure generated by the continuously rotating fan, even when the first air inlet hole on the fan cover is blocked, the outside air can still enter the opened spare hole, and enter the inside of the movable cover along the spare hole and the second air inlet hole, and continuously rush towards the heat sink under the drive of the fan, ensuring that the three-phase asynchronous motor can achieve the purpose of continuous and efficient heat dissipation.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows: A compact three-phase asynchronous motor of the present invention includes a motor main body and a fan connected to the tail of the motor main body; the fan is connected and driven by a main shaft at the tail of the motor main body; a fan cover is fixedly connected to the tail of the motor main body; the fan is located inside the fan cover; a first air inlet hole is provided on the end face of the fan cover away from the motor main body; an annular air outlet channel is formed between the inner wall of the end of the fan cover close to the motor main body and the inner end cover of the tail of the motor main body; the air outlet channel is communicated with the heat dissipation fins on the outer wall of the motor main body; external gas enters the inside of the fan cover along the first air inlet hole under the action of negative pressure, and blows towards the heat dissipation fins on the outer wall of the motor main body along the air outlet channel. One end of the fan cover close to the tail of the motor main body is turned inwards; a movable cover is slidably connected inside the fan cover; the movable cover is connected to the inwards-turned position of one end of the fan cover by a first spring; a second air inlet hole is correspondingly provided on the end face of the movable cover opposite to the first air inlet hole on the fan cover; a spare hole is provided at the transition position between the end face and the outer wall of the fan cover; the spare hole is staggered from the second air inlet hole; the spare hole is opened when the negative pressure generated by the fan is greater than the elastic force of the first spring; external gas can enter the inside of the fan cover along the spare hole and the second air inlet hole, and is discharged towards the heat dissipation fins along the air outlet channel.

[0007] Preferably, the fan cover is composed of a fan sleeve and a fan cover connected to the fan sleeve; the fan cover is rotationally and sealingly connected to the fan sleeve; the first air inlet hole is provided through the end face of the fan cover; a fan frame connected to the fan sleeve is provided outside the fan cover; a screw rod is rotatably connected to the fan frame near the center of the fan cover; the screw rod passes through the center of the fan cover and is fixedly connected to the center of the fan cover; one end of the screw rod extends to the center of the fan; a threaded hole in the center of the movable cover is in threaded transmission connection with the screw rod; the movable cover drives the screw rod and the fan cover to rotate during the negative pressure movement.

[0008] Preferably, the shape of the fan frame is strip-shaped; the fan frame is in radial contact with the outer surface of the fan cover; the fan frame scrapes the impurities on the outer wall of the fan cover during the rotation of the fan cover.

[0009] Preferably, the fan frame is vertically arranged; one end of the fan frame is arranged lower; the other end of the fan frame is arranged higher; the impurities on the outer wall of the fan cover are concentrated and fall along the fan frame under the cooperation of the fan frame and gravity.

[0010] Preferably, a block for preventing blockage is fixedly connected to the position of the outer wall of the movable cover corresponding to the spare hole in the initial state; the block for preventing blockage is located inside the spare hole when the outer wall of the movable cover is in contact with the inner wall of the fan cover; the shape of the block for preventing blockage is adapted to the shape of the spare hole.

[0011] Preferably, grooves are uniformly arranged on the outer wall of the movable cover around the center of the movable cover; the grooves are located corresponding to the positions of the anti-blocking blocks; the anti-blocking blocks are slidably connected in the corresponding grooves; the anti-blocking blocks are connected to the bottom of the grooves through second springs; the anti-blocking blocks push away the impurities in the spare holes under the elastic force of the second springs.

[0012] Preferably, guiding angles are arranged on both sides of the anti-blocking block in the circumferential direction of the movable cover; when the spare holes on the fan cover squeeze the guiding angles on the anti-blocking block, the guiding angles can be overcome to retract into the grooves against the second springs.

[0013] Preferably, the anti-blocking block is slidably and sealingly connected to the groove; the bottom of the groove is communicated with the inner wall of the movable cover through a through hole; when the first air inlet hole is blocked, the gas in the groove enters the inside of the movable cover along the through hole under the negative pressure generated by the fan.

[0014] The beneficial effects of the present invention are as follows: 1. Driven by the negative pressure generated by the continuously rotating fan of the present invention, even when the first air inlet hole on the fan cover is blocked, the outside gas can still enter the opened spare holes, and enter the inside of the movable cover along the spare holes and the second air inlet holes, and continuously rush towards the heat sink under the drive of the fan, ensuring that the three-phase asynchronous motor can achieve the purpose of continuous and efficient heat dissipation.

[0015] 2. By controlling the rotation of the fan cover, on the one hand, it serves the purpose of scraping the impurities on the outer wall of the fan cover. On the other hand, the rotation of the fan cover will generate centrifugal force, so that the impurities on the fan cover are thrown out under the action of the centrifugal force. More importantly, when the fan cover rotates inside the fan frame and the overall rotation of the fan cover are compared with the conventional method of using a scraping member to scrape while the scraped member does not move, in the process of cleaning the rotating fan cover in this application, it is not easy to collide with the surrounding circuits, thereby protecting the surrounding wire harnesses and components, realizing the cleaning of the impurities on the outer wall of the fan cover while protecting the surrounding components, and meeting the use requirements.

[0016] 3. The present invention fills the corresponding spare holes with the anti-blocking blocks when the spare holes are not in use, thereby preventing impurities from blocking the unused spare holes and further affecting the gas flow effect during the subsequent use of the spare holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the drawings and embodiments.

[0018] Figure 1 is a three-dimensional view of the present invention; Figure 2 is Figure 1 a three-dimensional view from another angle; Figure 3 is the exploded view of the present invention; Figure 4 is Figure 3 the three-dimensional view from another angle; Figure 5 is the cross-sectional view of Embodiment 1 of the present invention; Figure 6 is the cross-sectional view of the anti-blocking block and the movable cover in the present invention; Figure 7 is Figure 6 the enlarged view of part A in; Figure 8 is the three-dimensional view of the anti-blocking block in the present invention.

[0019] In the figure: motor main body 1, main shaft 11, air outlet duct 12, heat sink 13, fan 2, fan cover 34, fan sleeve 3, fan frame 31, screw rod 32, fan cover 4, first air inlet hole 41, spare hole 42, movable cover 5, first spring 51, second air inlet hole 52, threaded hole 53, groove 54, through hole 55, anti-blocking block 6, second spring 61, guiding angle 62. Specific Embodiments

[0020] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0021] As Figures 1 to 8 shown, the present invention is detailed in the following embodiments: Embodiment 1: A compact three-phase asynchronous motor, including a motor main body 1 and a fan 2 connected to the tail of the motor main body 1; the fan 2 is connected and driven by the main shaft 11 at the tail of the motor main body 1; the tail of the motor main body 1 is fixedly connected with a fan cover 34; the fan 2 is located inside the fan cover 34; the end face of the fan cover 34 away from the motor main body 1 is provided with a first air inlet hole 41; an annular air outlet duct 12 is formed between the inner wall of the end of the fan cover 34 close to the motor main body 1 and the inner end cover of the tail of the motor main body 1; the air outlet duct 12 is communicated with the heat sink 13 on the outer wall of the motor main body 1; external air enters the inside of the fan cover 34 along the first air inlet hole 41 under the action of negative pressure, and blows towards the heat sink 13 on the outer wall of the motor main body 1 along the air outlet duct 12; One end of the fan cover 34 near the tail of the motor body 1 is turned inwards; the movable cover 5 is slidably connected to the inner side of the fan cover 34; the movable cover 5 is connected to the inwards-turned position of one end of the fan cover 34 by a first spring 51; a second air inlet hole 52 is correspondingly arranged on the end face of the movable cover 5 opposite to the first air inlet hole 41 on the fan cover 34; a spare hole 42 is arranged at the transition position between the end face and the outer wall of the fan cover 34; the spare hole 42 is staggered from the second air inlet hole 52; the spare hole 42 is opened when the negative pressure generated by the fan 2 is greater than the elastic force of the first spring 51; external gas can enter the inner side of the fan cover 34 along the spare hole 42 and the second air inlet hole 52, and is discharged to the heat sink 13 along the air outlet channel 12.

[0022] In this embodiment, the fan cover 34 is composed of a fan sleeve 3 and a fan cover 4 connected to the fan sleeve 3; the fan cover 4 is rotatably and sealingly connected to the fan sleeve 3; the first air inlet hole 41 is arranged through the end face of the fan cover 4; a fan frame 31 connected to the fan sleeve 3 is arranged outside the fan cover 4; a screw rod 32 is rotatably connected to the fan frame 31 near the center of the fan cover 4; the screw rod 32 passes through the center of the fan cover 4 and is fixedly connected to the center of the fan cover 4; one end of the screw rod 32 extends to the center of the fan 2; a threaded hole 53 at the center of the movable cover 5 is in threaded transmission connection with the screw rod 32; the movable cover 5 drives the screw rod 32 and the fan cover 4 to rotate during the negative pressure movement; the spare hole 42 is arranged on the fan cover 4.

[0023] In this embodiment, the shape of the fan frame 31 is strip-shaped; the fan frame 31 is in radial contact with the outer surface of the fan cover 4; the fan frame 31 scrapes the impurities on the outer wall of the fan cover 4 during the rotation of the fan cover 4.

[0024] In this embodiment, the fan frame 31 is arranged vertically; one end of the fan frame 31 is arranged lower; the other end of the fan frame 31 is arranged higher; the impurities on the outer wall of the fan cover 4 are concentrated and fall along the fan frame 31 under the scraping of the fan frame 31 and the action of gravity; During operation, in some relatively messy environments, if the air inlet of the fan cover 34 on the tail of the three-phase asynchronous motor is blocked, external gas cannot enter the inner side of the fan cover 34 along the air inlet on the fan cover 34, resulting in the rotation of the fan 2 being unable to generate the wind blowing towards the heat sink 13, and further resulting in a poor heat dissipation effect of the heat sink 13. When the maintenance personnel cannot arrive at the scene for maintenance in time, the temperature of the three-phase asynchronous motor rises rapidly, affecting the efficiency and even causing faults in the three-phase asynchronous motor; Therefore, when the staff of the present invention checks that the three-phase asynchronous motor is fault-free, the three-phase asynchronous motor is placed in the corresponding position, and after the three-phase asynchronous motor is connected to the power supply, the controller is started to control the rotation of the three-phase asynchronous motor. When the three windings of the three-phase asynchronous motor are excited by three-phase alternating current, a rotating magnetic field will be generated on the stator; this rotating magnetic field further induces an electromotive force on the rotor, resulting in a rotating magnetic field induced in the rotor; due to the difference between the rotating magnetic fields, the rotor will try to catch up with the rotating magnetic field of the stator and generate a torque, which will drive the motor to rotate; the rotor will drive the main shaft 11 to rotate, and the main shaft 11 will drive the fan 2 to rotate. The external gas enters the inside of the fan cover 34 along the first air inlet hole 41 and the second air inlet hole 52 under the rotation of the fan 2, and under the action of the fan 2 inside the fan cover 34, the air inside the fan cover 34 is blown along the air outlet channel 12 to the heat sink 13 on the outer wall of the motor body 1, thereby taking away the heat on the heat sink 13 and achieving the purpose of cooling the motor body 1; if foreign objects around fall on the periphery of the first air inlet hole 41 of the fan cover 34, the foreign objects will adhere to the first air inlet hole 41 under the action of negative pressure, so that the first air inlet hole 41 is blocked. As the foreign objects around the first air inlet hole 41 increase, the external gas cannot enter the inside of the fan cover 34 along the first air inlet hole 41 and the second air inlet hole 52. When the fan 2 continues to rotate with the main shaft 11, a negative pressure will be formed inside the fan cover 34. In this way, the movable cover 5 moves inward along the inside of the fan cover 34 against the elastic force of the first spring 51 near one end of the fan cover 34, so that a gap is formed between the movable cover 5 and the fan cover 4. Even when the first air inlet hole 41 is blocked, the external gas can enter the gap between the movable cover 5 and the fan cover 4 along the spare hole 42, and enter the inside of the movable cover 5 along the gap between the movable cover 5 and the fan cover 4 and the second air inlet hole 52. The air flow inside the movable cover 5 is discharged along the air outlet channel 12 under the guiding action of the fan 2, realizing the heat dissipation of the heat sink 13 on the outer wall of the motor body 1. In this way, when the first air inlet hole 41 is blocked, it is avoided that the heat sink 13 cannot be blown by the air flow generated by the fan 2, resulting in damage to the three-phase asynchronous motor.The movable cover 5 is connected to the inner side of the fan cover 34 through the first spring 51. Therefore, the first spring 51 can limit the movable cover 5 and prevent the movable cover 5 from rotating. During the movement of the movable cover 5 towards the main shaft 11, the threaded hole 53 will move on the screw rod 32. The screw rod 32 is in threaded transmission connection with the threaded hole 53. Therefore, the screw rod 32 will rotate under the movement of the movable cover 5. The rotating screw rod 32 will drive the fixedly connected fan cover 4 to rotate. The rotation of the fan cover 4 will drive the first air inlet hole 41 to rotate. During the rotation of the fan cover 4, the impurities on the outer wall of the fan cover 4 will rotate synchronously. Since the outer wall of the fan cover 4 contacts the vertically arranged fan frame 31, during the rotation of the fan cover 4, the foreign matters on the outer wall of the fan cover 4 will be scraped off by the fan frame 31. Since the fan frame 31 is vertically arranged, during the process that the foreign matters on the outer wall of the fan cover 4 are scraped off by the fan frame 31 and concentrated on both sides of the fan frame 31, they will fall off under the action of gravity and the vibration force generated by the motor body 1, thus achieving the purpose of cleaning the first air inlet hole 41 on the fan cover 4 and ensuring the smoothness of the first air inlet hole 41. After the first air inlet hole 41 is dredged, the first air inlet hole 41 with a diameter larger than the spare hole 42 is communicated with the second air inlet hole 52. The outside air will enter the second air inlet hole 52 along the first air inlet hole 41, and then enter the inner side of the movable cover 5 along the second air inlet hole 52. The air inside the movable cover 5 will be blown towards the heat sink 13 on the outer wall of the motor body 1 along the air outlet channel 12 under the action of the fan 2. When the first air inlet hole 41 is dredged, the negative pressure generated by the fan 2 inside the movable cover 5 will be lower than the elastic force of the first spring 51. In this way, the first spring 51 will drive the movable cover 5 to move away from the main shaft 11, so that the movable cover 5 contacts the inner wall of the fan cover 4, blocking the spare hole 42 on the fan cover 4. During the movement of the movable cover 5 away from the main shaft 11, the screw rod 32 will be driven to rotate again. The rotation of the screw rod 32 will drive the fan cover 4 to rotate, so that the outer wall of the fan cover 4 is cleaned again until the outer wall of the movable cover 5 contacts the inner wall of the fan cover 4, and the first air inlet hole 41 and the second air inlet hole 52 are completely overlapped. In this application, by controlling the rotation of the fan cover 4, on the one hand, it serves the purpose of scraping the impurities on the outer wall of the fan cover 4. On the other hand, the rotation of the fan cover 4 will generate centrifugal force, causing the impurities on the fan cover 4 to be thrown out under the action of the centrifugal force. More importantly, the rotation of the fan cover 4 inside the fan frame 31 and the overall rotation of the fan cover 4 are compared with the conventional method of using a scraping part to scrape while the scraped part remains stationary. In the process of cleaning the rotating fan cover 4 in this application, it is not easy to collide with the surrounding circuits, thus protecting the surrounding wire harnesses and components. It realizes the cleaning of the impurities on the outer wall of the fan cover 4 while protecting the surrounding components, meeting the usage requirements. In this application, different from the conventional design, the negative pressure generated by the fan 2 is used to open the spare hole 42. Compared with the conventional idea of using an electric push rod to push the movable cover 5 to open the spare hole 42, the structure of this application is more ingenious and the parts are more compact. At the same time, in this application, the cooperation between the movable cover 5 and the screw rod 32 is used to clean the impurities on the outer wall of the fan cover 4. Compared with the conventional setting of a separate cleaning mechanism, the structure of this application is more ingenious and the components are more compact. Therefore, while achieving the purpose of uninterrupted and efficient heat dissipation, this application belongs to a compact three-phase asynchronous motor. Driven by the negative pressure generated by the continuously rotating fan 2, even when the first air inlet hole 41 on the fan cover 34 is blocked, the outside air can still enter the opened spare hole 42, and enter the inside of the movable cover 5 along the spare hole 42 and the second air inlet hole 52, and continuously rush towards the heat sink 13 under the drive of the fan 2, ensuring that the three-phase asynchronous motor can achieve the purpose of continuous and efficient heat dissipation.

[0025] Embodiment 2. The difference between this embodiment and Embodiment 1 is that: An anti-blocking block 6 is fixedly connected to the position of the outer wall of the movable cover 5 corresponding to the spare hole 42 in the initial state; the anti-blocking block 6 is located inside the spare hole 42 when the outer wall of the movable cover 5 is in contact with the inner wall of the fan cover 4; the shape of the anti-blocking block 6 is adapted to the shape of the spare hole 42.

[0026] In this embodiment, grooves 54 are evenly arranged around the center of the movable cover 5 on the outer wall of the movable cover 5; the grooves 54 are located corresponding to the position of the anti-blocking block 6; the anti-blocking block 6 is slidably connected in the corresponding groove 54; a second spring 61 is connected between the anti-blocking block 6 and the bottom of the groove 54; the anti-blocking block 6 pushes away the impurities in the spare hole 42 under the elastic force of the second spring 61.

[0027] In this embodiment, guiding angles 62 are arranged on both sides of the anti-blocking block 6 in the circumferential direction of the movable cover 5; the guiding angles 62 on the anti-blocking block 6 are squeezed by the spare hole 42 on the fan cover 4, and the guiding angles 62 can be made to retract into the groove 54 against the second spring 61.

[0028] In this embodiment, the anti-blocking block 6 is slidably and sealingly connected to the groove 54; the bottom of the groove 54 is communicated with the inner wall of the movable cover 5 through a through hole 55; when the first air inlet hole 41 is blocked, the gas in the groove 54 enters the inside of the movable cover 5 along the through hole 55 under the negative pressure generated by the fan 2. During operation, when the first air inlet hole 41 is blocked by foreign objects, the rotating fan 2 will create a negative pressure inside the fan cover 34, causing the movable cover 5 to approach the main shaft 11 under the action of the negative pressure. During the movement of the movable cover 5 towards the main shaft 11, it will drive the screw rod 32 to rotate. The rotating screw rod 32 will drive the fan cover 4 to rotate. The outer wall of the rotating fan cover 4 is scraped by the fan frame 31 to achieve cleaning. The rotating fan cover 4 will drive the spare hole 42 to rotate. During the rotation of the spare hole 42, foreign objects around it are not likely to block the spare hole 42. As the spare hole 42 rotates around the screw rod 32 with the fan cover 4, it will squeeze one of the guiding angles 62 on the anti-blocking block 6, causing the guiding angle 62 to move closer to the bottom of the groove 54 under pressure and overcoming the second spring 61. In this way, the presence of the anti-blocking block 6 does not affect the rotation of the fan cover 4. More importantly, when the first air inlet hole 41 is blocked, a negative pressure will be generated during the continuous rotation of the fan 2. The gas in the groove 54 will enter the inner side of the movable cover 5 along the through hole 55 under the action of the negative pressure. The anti-blocking block 6 will move closer to the bottom of the groove 54 and overcome the second spring 61 during the process of the gas in the groove 54 being pumped away. In this way, the anti-blocking block 6 will move out of the spare hole 42, opening the spare hole 42. External gas will enter between the inner wall of the fan cover 4 and the outer wall of the movable cover 5 along the spare hole 42 and then enter the inner side of the movable cover 5 along the second air inlet hole 52. When the outer wall of the fan cover 4 has been scraped by the fan frame 31, the first air inlet hole 41 will be unblocked. In this way, external gas will enter the inner side of the movable cover 5 along the first air inlet hole 41 and the second air inlet hole 52. Subsequently, the movable cover 5 will move away from the main shaft 11 under the elastic force of the first spring 51. During the movement of the movable cover 5 away from the main shaft 11, it will drive the screw rod 32 and the fan cover 4 to rotate again. The outer wall of the fan cover 4 will be scraped by the fan frame 31 again. During the relative rotation between the rotating fan cover 4 and the movable cover 5, the anti-blocking block 6 on the outer wall of the movable cover 5 will scrape the impurities on the inner wall of the fan cover 4, causing the impurities between the inner wall of the fan cover 4 and the outer wall of the movable cover 5 to fall into the spare hole 42. As the movable cover 5 continues to move away from the main shaft 11, the anti-blocking block 6 will enter the spare hole 42 under the action of the second spring 61. As the spare hole 42 rotates with the fan cover 4, it will squeeze the other guiding angle 62, causing the anti-blocking block 6 to move out of the spare hole 42. In this way, the anti-blocking block 6 repeatedly enters and moves out of different spare holes 42 until the movable cover 5 and the fan cover 4 stop relative rotation when the outer wall of the movable cover 5 contacts the inner wall of the fan cover 4. Finally, the anti-blocking block 6 will be pushed by the second spring 61 into the spare hole 42 in the initial state. In this embodiment, the anti-blocking block 6 scrapes and cleans the impurities between the inner wall of the fan cover 4 and the outer wall of the movable cover 5, thereby preventing the impurities between the inner wall of the fan cover 4 and the outer wall of the movable cover 5 from affecting the reset of the movable cover 5, and further enabling the anti-blocking block 6 to completely block the spare hole 42;In this embodiment, the anti-blocking block 6 repeatedly enters or exits different spare holes 42, so that the impurities in the spare holes 42 are pushed away, thereby preventing the residual impurities in the spare holes 42 from affecting the air flow effect when the spare holes 42 are enabled again; in this embodiment, by connecting the groove 54 with the inner wall of the movable cover 5, the gas in the groove 54 can be sucked into the inner side of the movable cover 5 under the action of negative pressure when the first air inlet hole 41 is blocked, thereby reducing the resistance between the anti-blocking block 6 and the corresponding spare hole 42 and facilitating the opening of the spare hole 42. When external gas enters along the first air inlet hole 41 usually, the air pressure generated by the fan 2 inside the movable cover 5 is balanced with the elastic force of the second spring 61; in this embodiment, when the spare hole 42 is not enabled, the corresponding spare hole 42 is filled by the anti-blocking block 6, thereby preventing impurities from blocking the unused spare hole 42 and further affecting the gas flow effect during the subsequent activation of the spare hole 42.

[0029] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the Figure 1 orientation or positional relationship shown, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and cannot be understood as indicating or implying relative importance.

[0030] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A compact three-phase asynchronous motor, comprising a motor body (1) and a fan (2) connected to the tail of the motor body (1); the fan (2) is connected and driven by a main shaft (11) at the tail of the motor body (1); a fan cover (34) is fixedly connected to the tail of the motor body (1); the fan (2) is located inside the fan cover (34); it is characterized in that: One end of the fan cover (34) close to the tail of the motor body (1) is turned inwards; an activity cover (5) is slidably connected inside the fan cover (34); the activity cover (5) is connected to the inwards-turning position of one end of the fan cover (34) through a first spring (51); a second air inlet hole (52) is correspondingly arranged on the end face of the activity cover (5) opposite to the first air inlet hole (41) on the fan cover (34); a spare hole (42) is arranged at the transition position between the end face and the outer wall of the fan cover (34); the spare hole (42) is staggered from the second air inlet hole (52); the spare hole (42) is opened when the negative pressure generated by the fan (2) is greater than the elastic force of the first spring (51); external gas can enter the inside of the fan cover (34) along the spare hole (42) and the second air inlet hole (52), and is discharged to the heat sink (13) along the air outlet channel (12).

2. A compact three-phase asynchronous motor according to claim 1, characterized in that: The fan cover (34) is composed of a fan sleeve (3) and a fan cover (4) connected to the fan sleeve (3); the fan cover (4) is rotationally and sealingly connected to the fan sleeve (3); the first air inlet hole (41) is arranged through the end face of the fan cover (4); a fan frame (31) connected to the fan sleeve (3) is arranged outside the fan cover (4); a screw rod (32) is rotatably connected to the fan frame (31) near the center position of the fan cover (4); the screw rod (32) passes through the center of the fan cover (4) and is fixedly connected to the center of the fan cover (4); one end of the screw rod (32) extends to the center of the fan (2); a threaded hole (53) at the center of the activity cover (5) is in threaded transmission connection with the screw rod (32); the activity cover (5) drives the screw rod (32) and the fan cover (4) to rotate during the negative pressure movement process; the spare hole (42) is arranged on the fan cover (4).

3. A compact three-phase asynchronous motor according to claim 2, characterized in that: The shape of the fan frame (31) is strip-shaped; the fan frame (31) is in radial contact with the outer surface of the fan cover (4); the fan frame (31) scrapes the impurities on the outer wall of the fan cover (4) during the rotation of the fan cover (4).

4. A compact three-phase asynchronous motor according to claim 3, characterized in that: The fan frame (31) is vertically arranged; one end of the fan frame (31) is arranged at a lower position; the other end of the fan frame (31) is arranged at an upper position; the impurities on the outer wall of the fan cover (4) are concentrated and fall along the fan frame (31) under the cooperation of the gravity under the scraping of the fan frame (31).

5. A compact three-phase asynchronous motor according to claim 2, characterized in that: An anti-blocking block (6) is fixedly connected to the position of the outer wall of the activity cover (5) corresponding to the spare hole (42) in the initial state; the anti-blocking block (6) is located inside the spare hole (42) when the outer wall of the activity cover (5) is in contact with the inner wall of the fan cover (4); the shape of the anti-blocking block (6) is adapted to the shape of the spare hole (42).

6. A compact three-phase asynchronous motor according to claim 5, characterized in that: The outer wall of the movable cover (5) is evenly provided with grooves (54) around the center of the movable cover (5); the grooves (54) are located corresponding to the positions of the anti-blocking blocks (6); the anti-blocking blocks (6) are slidably connected in the corresponding grooves (54); the anti-blocking blocks (6) are connected to the bottoms of the grooves (54) through second springs (61); the anti-blocking blocks (6) push away impurities in the spare holes (42) under the elastic force of the second springs (61).

7. A compact three-phase asynchronous motor according to claim 6, characterized in that: Both sides of the anti-blocking block (6) in the circumferential direction of the movable cover (5) are provided with guiding angles (62); when the spare holes (42) on the fan cover (4) press against the guiding angles (62) on the anti-blocking block (6), the guiding angles (62) can be retracted into the grooves (54) against the second springs (61).

8. A compact three-phase asynchronous motor according to claim 6, wherein: The anti-blocking block (6) is slidably and sealingly connected to the groove (54); the bottom of the groove (54) is communicated with the inner wall of the movable cover (5) through a through hole (55); when the first air inlet hole (41) is blocked, the gas in the groove (54) enters the inner side of the movable cover (5) along the through hole (55) under the negative pressure generated by the fan (2).

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