Box-type motor air cooling system

Abstract

The application discloses a box type motor air cooling system, which comprises a motor shell, a rotor shaft, a motor stator, a motor rotor, a wind box, an inner circulation centrifugal fan and an outer circulation centrifugal fan. The motor stator is fixed to the inner wall of the motor shell in the same axis. The motor rotor is fixed to the rotor shaft in the same axis, and the rotor shaft is rotatably connected to the end covers at the two ends of the motor shell through bearings. The inner circulation centrifugal fan and the outer circulation centrifugal fan are synchronously installed on the rotor shaft in the same axis. The inner circulation centrifugal fan is arranged in the front part of the stator-rotor cavity in the motor shell. The outer circulation centrifugal fan is arranged outside the tail end of the motor shell. The outer circulation airflow generated by the outer circulation centrifugal fan can take away the heat in the inner circulation airflow generated by the inner circulation centrifugal fan during the process of passing through the wind box. The box type motor air cooling system has a self-adaptive air volume adjusting function.

Description

Technical Field

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

[0002] In the operation of constant power motors, two typical operating conditions are commonly observed: high load at low speed and low load at high speed. Traditional motor air-cooling systems typically employ fixed-structure fans and air ducts to address heat dissipation, leading to the following problems:

[0003] Insufficient cooling at low speeds: When running under high load and low speed, the motor generates a lot of heat, but the airflow generated by the fixed fan is insufficient to remove enough heat, which may cause the motor temperature to rise too high, affecting performance or even damaging the insulation.

[0004] Efficiency and noise issues at high speeds: When running at low load and high speed, the heat generated by the motor itself decreases, but the airflow generated by the fixed fan at high speed is too large. This not only causes unnecessary "wind friction loss", which occupies part of the motor's output power and reduces the overall efficiency, but also generates strong aerodynamic howling noise at the air inlet and outlet.

[0005] Unadjustable airflow: Current technology lacks an effective means to automatically adjust cooling airflow based on speed and load. Although some complex electronic control or mechanical linkage schemes exist, they are often structurally complex, costly, or lack reliability.

[0006] Mixing internal and external airflow: Some traditional designs mix internal and external circulating airflow, which can easily bring external dust, moisture and other pollutants into the motor, affecting the motor's lifespan and operational reliability. Summary of the Invention

[0007] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a box-type motor air-cooling system with adaptive air volume adjustment function.

[0008] Technical Solution: To achieve the above objectives, the present invention provides a box-type motor air-cooling system, comprising a motor housing, a rotor shaft, a motor stator, a motor rotor; an air box, an internal circulation centrifugal fan, and an external circulation centrifugal fan; the motor stator is coaxially fixed to the inner wall of the motor housing; the motor rotor is coaxially fixed to the rotor shaft, and the rotor shaft is rotatably engaged with the end caps at both ends of the motor housing via bearings; both the internal circulation centrifugal fan and the external circulation centrifugal fan are coaxially and synchronously mounted on the rotor shaft; the internal circulation centrifugal fan is located at the front of the stator-rotor cavity inside the motor housing; the external circulation centrifugal fan is located at the outer side of the rear end of the motor housing; the external circulation centrifugal fan generates external circulation airflow, which carries away the heat in the internal circulation airflow generated by the internal circulation centrifugal fan during operation as it passes through the air box.

[0009] Furthermore, an annular isolation plate is integrally and coaxially disposed inside the motor housing, between the motor rotor and the internal circulation centrifugal fan; the portion of the annular isolation plate near the axis is an arc-shaped lip that conforms to the outer contour of the internal circulation centrifugal fan; the arc-shaped lip and the arc-shaped outer contour of the internal circulation centrifugal fan near the motor rotor are fitted with a clearance; an annular air pressure chamber is formed between the front end cover of the motor housing and the annular isolation plate, distributed around the outer periphery of the internal circulation centrifugal fan; the outer periphery of the annular air pressure chamber is connected to the front end of the ventilation box through air guide port a on the motor housing; the rear end of the stator and rotor chambers inside the motor housing forms a negative pressure chamber, and the outer ring of the negative pressure chamber is connected to the rear end of the ventilation box through air guide port b on the motor housing.

[0010] Furthermore, the external circulation centrifugal fan is coaxially located inside the external circulation centrifugal fan housing, which is fixed to the air box. The tail end of the external circulation centrifugal fan housing is provided with an external circulation air inlet that connects to the outside. An external circulation air pressure box is fixedly installed at the rear end of the air box, and the centrifugal air outlet of the external circulation centrifugal fan housing is connected to the external circulation air pressure box. Several parallel heat exchange air duct arrays pass horizontally through the air box. The rear end of each heat exchange air duct array is connected to the external circulation air pressure box, and the front end of each heat exchange air duct array is connected to the outside.

[0011] Furthermore, the centrifugal air inlet is located in the center of the internal circulation centrifugal fan, near the motor rotor.

[0012] Furthermore, during motor operation, the high-speed rotating internal circulation centrifugal fan creates centrifugal wind pressure within the annular air pressure chamber, while a centrifugal negative pressure is created at the centrifugal air inlet. This negative pressure at the centrifugal air inlet is transmitted to the negative pressure chamber through the air gap between the stator and rotor, causing the negative pressure chamber to continuously draw air from the tail end of the air box through the b air guide port. Meanwhile, the gas in the annular air pressure chamber, under the action of wind pressure, continuously passes through the a air guide port and is forced into the front end of the air box, thus ensuring that the internal circulation gas generated by the internal circulation centrifugal fan continuously flows through the air box. At the same time, the external circulation centrifugal fan continuously forces external air into the external circulation air pressure box, creating wind pressure within it. The external air in the external circulation air pressure box is continuously discharged forward to the outside through the heat exchange air duct array, thereby forming an external circulation airflow.

[0013] Furthermore, the internal circulation centrifugal fan includes a central fixed sleeve, a fan disc, centrifugal blades, and an arc-shaped air guide ring. The centrifugal air inlet is located on the inner ring of the arc-shaped air guide ring. The central fixed sleeve is coaxially fixed and locked onto the rotor shaft by a locking device. The fan disc is coaxially and integrally connected to the central fixed sleeve. The centrifugal blades, arranged in a circumferential array, are integrally set between the arc-shaped air guide ring and the fan disc, and a centrifugal blasting channel is formed between any two adjacent centrifugal blades.

[0014] Furthermore, the centrifugal blades are hollow plate structures, with the hollow portion inside each blade being a plate-shaped distal oil chamber filled with oil. A ring-shaped piston chamber filled with oil is coaxially arranged within the central fixed sleeve, and each plate-shaped distal oil chamber is connected to the rear end of the ring-shaped piston chamber via a liquid guiding channel within the fan. A piston is coaxially and movably arranged at the front of the ring-shaped piston chamber, and a limiting inner edge that cooperates with the piston is provided at the front end of the ring-shaped piston chamber. A spring that generates forward thrust on the piston is provided within the ring-shaped piston chamber. Hollow grooves are laterally arranged on both sides of the end of each centrifugal blade furthest from the axis of the internal circulation centrifugal fan. An elastic diaphragm is sealed and covered outside the hollow grooves, and the edge of the elastic diaphragm is sealed to the surface of the centrifugal blade using a sealing adhesive.

[0015] In the initial state, the piston is limited by the spring and the inner edge of the piston is limited, so that an initial negative pressure is formed in the annular piston cavity. The negative pressure in the annular piston cavity is transmitted to the plate-shaped distal oil tank through each liquid guiding channel, so that each elastic diaphragm is concave inward and convex towards the inner side of the plate-shaped distal oil tank under the action of negative pressure.

[0016] Furthermore, when the motor speed is in the high speed range, the oil in the liquid guiding channel flows into the plate-shaped distal oil chamber under the stronger centrifugal force, thereby changing the negative pressure in the plate-shaped distal oil chamber to positive pressure. The negative pressure intensity in the annular piston chamber is further enhanced, and the piston moves further backward to adapt, so that a narrow area is formed in the local centrifugal blasting channel between any two adjacent centrifugal blades.

[0017] Beneficial effects: This invention proposes a box-type motor air-cooling system with adaptive airflow adjustment function, the core innovations of which are as follows:

[0018] Innovatively, it features two completely isolated sets of internal and external circulating air ducts. The internal circulating airflow circulates in a closed loop within the motor, preventing external contaminants from entering; the external circulating airflow flows within the air box and heat exchange tubes, dedicated to heat dissipation. Both achieve efficient heat exchange through heat exchange at the heat exchange duct array within the air box, realizing a balance between efficient heat dissipation and internal cleanliness.

[0019] By integrating a hydraulic-mechanical automatic adjustment mechanism into the centrifugal fan blades, the fan can automatically change its performance according to the rotational speed.

[0020] Innovative Structure: This structure includes hollow centrifugal blades, an internal plate-shaped distal oil reservoir, an annular piston chamber connected to the reservoir, a piston, a spring, and an elastic diaphragm on the blade surface. Utilizing the centrifugal force changes caused by rotational speed variations, the oil is redistributed between the reservoir and the piston chamber, altering the pressure within the reservoir and forcing the elastic diaphragm to deform inwards or outwards. At low speeds: the diaphragm is concave, ensuring unobstructed airflow and maximizing air volume to meet high-load heat dissipation requirements. At high speeds: the diaphragm bulges outwards, creating a narrow zone in the airflow, actively increasing airflow resistance, suppressing airflow, effectively reducing windage losses and airflow noise, and improving motor efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of this solution;

[0022] Figure 2 This is a schematic diagram of the overall structure of an internal circulation centrifugal fan;

[0023] Figure 3 for Figure 1 The enlarged diagram at mark 16 shows the three states;

[0024] Figure 4 This is a first partial cross-sectional view of an internal circulation centrifugal fan;

[0025] Figure 5 This is a second partial cross-sectional view of an internal circulation centrifugal fan. Detailed Implementation

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

[0027] like Figures 1 to 5 The illustrated box-type air-cooled motor system, such as Figure 1 The system includes a motor housing 9, a rotor shaft 13, a motor stator 11, and a motor rotor 10; a wind box 42, an internal circulation centrifugal fan 5, and an external circulation centrifugal fan 45; the motor stator 11 is coaxially fixed to the inner wall of the motor housing 9; the motor rotor 10 is coaxially fixed to the rotor shaft 13, and the rotor shaft 13 is rotatably engaged with the end caps at both ends of the motor housing 9 through bearings; the internal circulation centrifugal fan 5 and the external circulation centrifugal fan 45 are both coaxially and synchronously installed on the rotor shaft 13; the internal circulation centrifugal fan 5 is located at the front of the stator and rotor chamber inside the motor housing 9; the external circulation centrifugal fan 45 is located on the outer side of the tail end of the motor housing 9; the external circulation centrifugal fan 45 generates external circulation airflow, which carries away the heat in the internal circulation airflow generated by the internal circulation centrifugal fan 5 during operation as it passes through the wind box 42.

[0028] In this scheme, the internal circulation centrifugal fan 5 and the external circulation centrifugal fan 45 have the same structure and working principle. The specific structure and principle of the internal circulation centrifugal fan 5 will be introduced separately below.

[0029] An annular isolation plate 8 is integrally and coaxially disposed inside the motor housing 9, between the motor rotor 10 and the internal circulation centrifugal fan 5; the portion of the annular isolation plate 8 near the axis is an arc-shaped lip 7 that conforms to the outer contour of the internal circulation centrifugal fan 5; the arc-shaped lip 7 and the arc-shaped outer contour of the internal circulation centrifugal fan 5 near the motor rotor 10 are fitted with a clearance; the gap between the arc-shaped lip 7 and the internal circulation centrifugal fan 5 is usually controlled within the range of 1-2mm, which ensures no contact friction and reduces airflow leakage.

[0030] An annular air pressure chamber 6 is formed between the front cover of the motor housing 9 and the annular isolation plate 8, which is distributed around the outer periphery of the internal circulation centrifugal fan 5; the outer periphery of the annular air pressure chamber 6 is connected to the front end of the ventilation box 42 through the air guide port 9.1 on the motor housing 9.

[0031] The tail end of the stator and rotor chambers inside the motor housing 9 forms a negative pressure chamber 12, and the outer ring of the negative pressure chamber 12 is connected to the rear end of the ventilation box 42 through the b air guide 9.2 on the motor housing 9.

[0032] The external circulation centrifugal fan 45 is coaxially located inside the external circulation centrifugal fan housing 46. The external circulation centrifugal fan housing 46 is fixed to the air box 42. The tail end of the external circulation centrifugal fan housing 46 is provided with an external circulation air inlet 61 that connects to the outside.

[0033] An external circulation air pressure box 43 is fixedly installed at the rear end of the air box 42. The centrifugal outlet 62 of the external circulation centrifugal fan casing 46 is connected to the external circulation air pressure box 43. Several parallel heat exchange air duct arrays 41 pass horizontally through the air box 42. The rear ends of the heat exchange air duct arrays 41 are all connected to the external circulation air pressure box 43, and the front ends of the heat exchange air duct arrays 41 are all connected to the outside. The centrifugal air inlet 17 is located in the center of the side of the internal circulation centrifugal fan 5 closest to the motor rotor 10. The heat exchange air duct array 41 is composed of multiple parallel copper or aluminum tubes. Copper tubes have good thermal conductivity, while aluminum tubes are lightweight and low in cost. The number of heat exchange air ducts is determined according to the heat dissipation requirements, usually 10-50, with a diameter of 5-15mm and a length matching the air box.

[0034] Overall working principle:

[0035] When the motor is running, the high-speed rotating internal circulation centrifugal fan 5 creates centrifugal air pressure in the annular air pressure chamber 6, while a centrifugal negative pressure is created at the centrifugal air inlet 17. The centrifugal negative pressure at the centrifugal air inlet 17 is transmitted to the negative pressure chamber 12 through the air gap between the stator and rotor, so that the negative pressure chamber 12 continuously draws air from the tail end of the air box 42 through the b air guide 9.2. Under the action of air pressure, the gas in the annular air pressure chamber 6 is continuously forced into the front end of the air box 42 through the a air guide 9.1, so that the internal circulation gas generated by the internal circulation centrifugal fan 5 continuously flows through the air box. 42; Simultaneously, the external circulation centrifugal fan 45 continuously compresses external air into the external circulation air pressure box 43, creating air pressure within the external circulation air pressure box 43. The external air in the external circulation air pressure box 43 is continuously discharged forward to the outside through the heat exchange duct array 41, thus forming an external circulation airflow. This external circulation airflow continuously absorbs heat from the internal circulation gas flowing through the air box 42 in the form of heat exchange as it flows through the heat exchange duct array 41, thereby achieving efficient heat dissipation for the motor's internal components. The overall working principle is based on the pressure difference driving the airflow of the centrifugal fan. When the internal circulation centrifugal fan 5 rotates, positive pressure is generated in the annular air pressure chamber 6, and negative pressure is generated at the centrifugal air inlet 17, forming an internal circulation airflow path. The external circulation centrifugal fan 45 independently drives external air, exchanging heat with the internal circulation airflow through the heat exchange duct array 41. The heat exchange efficiency depends on the airflow velocity, heat exchange area, and the thermal conductivity of the material. In existing technologies, motor cooling systems often mix internal and external airflows, which can easily introduce dust and moisture. This solution avoids this problem by separating the circulation.

[0036] Constant power motors operate under two conditions: high load at low speed and low load at high speed. Traditional motors require a more efficient airflow to ensure sufficient cooling airflow during high load at low speed. However, during low load at high speed, excessive cooling airflow can cause whistling noise at the inlet and outlet, while simultaneously leading to a sharp increase in windage losses from the high-speed fan blades, reducing motor efficiency and inhibiting further speed increases. To alleviate this problem, the following solution was designed based on the aforementioned structure:

[0037] like Figures 2 to 5 As shown, the internal circulation centrifugal fan 5 includes a central fixed sleeve 4, a fan disc 3, centrifugal blades 1, and an arc-shaped air guide ring 2. The centrifugal air inlet 17 is located within the inner ring of the arc-shaped air guide ring 2. The central fixed sleeve 4 is coaxially and securely locked to the rotor shaft 13 by locking components. The fan disc 3 is coaxially and integrally connected to the central fixed sleeve 4. The centrifugal blades 1, arranged in a circumferential array, are integrally disposed between the arc-shaped air guide ring 2 and the fan disc 3, forming a centrifugal blasting channel 15 between any two adjacent centrifugal blades 1. The central fixed sleeve 4 is made of stainless steel or high-strength aluminum and is fixed to the rotor shaft 13 by keyways and locking nuts to ensure synchronous rotation.

[0038] The centrifugal blade 1 has a hollow plate structure, and the hollow part inside each centrifugal blade 1 is a plate-shaped distal oil tank 22 filled with oil. An annular piston chamber 26 filled with oil is coaxially arranged inside the central fixed sleeve 4. Each plate-shaped distal oil tank 22 is connected to the rear end of the annular piston chamber 26 through a liquid guiding channel 23 in the fan 3. A piston 25 is coaxially and movably arranged at the front part of the annular piston chamber 26, and a limiting inner edge 28 that limits and cooperates with the piston 25 is provided at the front end of the annular piston chamber 26. A spring 24 is provided inside the annular piston chamber 26 to generate a forward thrust on the piston 25. The plate-shaped distal oil tank 22 is filled with silicone oil or mineral oil with a viscosity selected between 100-500 cSt to ensure moderate fluidity under centrifugal force. The piston 25 inside the annular piston chamber 26 is made of a wear-resistant polymer such as polytetrafluoroethylene.

[0039] Each centrifugal blade 1 has transversely arranged perforated grooves 14a on both sides of the end furthest from the axis of the internal circulation centrifugal fan 5. An elastic diaphragm 14 is sealed to the outside of the perforated grooves 14a. The edges of the elastic diaphragm 14 are sealed to the surface of the centrifugal blade 1 using a suitable sealing method such as a sealing adhesive or heat sealing. The elastic diaphragm 14 is made of oil-resistant rubber or silicone material, with a thickness of 0.5-1mm, and possesses high elasticity and fatigue resistance. Epoxy resin or polyurethane adhesive is used as the sealing adhesive to ensure it does not detach under high-speed rotation.

[0040] In the initial state, the piston 25 is limited by the thrust of the spring 24, which engages with the inner edge 28 to create an initial negative pressure within the annular piston cavity 26. This negative pressure is transmitted to the plate-shaped distal oil reservoir 22 through the fluid channels 23, causing the elastic diaphragms 14 to concave inward and convex outward towards the inner side of the plate-shaped distal oil reservoir 22 under the influence of the negative pressure. Figure 3 As shown in the diagram above. In the initial state, the thrust of spring 24 causes piston 25 to press tightly against the inner edge of the limiting valve 28, and the volume of the annular piston chamber 26 is at its maximum. Since the oil is incompressible, a negative pressure of approximately -0.1 to -0.3 bar is formed, causing the elastic diaphragm 14 to be concave inward by 3-8 mm. This design ensures unobstructed airflow when stationary or at low speeds.

[0041] When the motor speed is in the low-speed range, the oil in the fluid guide channel 23 flows into the plate-shaped distal oil chamber 22 under the influence of centrifugal force, thereby weakening the negative pressure intensity in the plate-shaped distal oil chamber 22. The negative pressure intensity in the annular piston chamber 26 increases, and the piston 25 moves backward adaptively. The inward concavity of the elastic diaphragm 14 is weaker than in the initial state, but without outward convexity. Figure 3As shown in the diagram above, this ensures that the centrifugal airflow channel 15 between any two adjacent centrifugal blades 1 always remains in optimal unobstructed condition; thus, the internal circulation centrifugal fan 5 can smoothly drive the internal circulation airflow to operate efficiently, thereby ensuring the heat dissipation performance of the motor under low speed and high load conditions. In the low speed range (e.g., 0-1000 rpm), the centrifugal force is small, the flow of oil to the plate-shaped telecentric oil tank 22 is limited, the negative pressure in the plate-shaped telecentric oil tank 22 is weakened to -0.05 to -0.1 bar, the piston 25 moves slightly backward under the action of spring force, the inward concavity of the elastic diaphragm 14 is reduced to 2-5 mm, the centrifugal airflow channel 15 remains unobstructed, the airflow is maximized, and the heat dissipation requirements of high load are met.

[0042] When the motor speed is in the high-speed range, the oil in the fluid guiding channel 23 flows into the plate-shaped distal oil tank 22 under the stronger centrifugal force, thereby changing the negative pressure in the plate-shaped distal oil tank 22 to a positive pressure. The negative pressure intensity in the annular piston chamber 26 is further enhanced, and the piston 25 moves further backward adaptively. The elastic diaphragm 14 changes from its original concave shape to an convex shape, such as... Figure 3 As shown in the figure below, the higher the rotational speed, the greater the outward convexity, thus forming a narrow section 36 in the centrifugal air-throwing channel 15 between any two adjacent centrifugal blades 1. This suppresses the centrifugal flow of the internal circulation centrifugal fan 5, effectively reducing the wind friction and wind load of the internal circulation centrifugal fan 5, and thus improving the motor operating efficiency. In the high-speed range (e.g., above 3000 rpm), the centrifugal force increases significantly, and a large amount of oil flows into the plate-shaped distal oil tank 22, causing its internal pressure to become positive (0.1-0.5 bar). The negative pressure in the annular piston chamber 26 increases to -0.5 bar, and the elastic diaphragm 14 convexes significantly to form the narrow section 36, reducing the cross-sectional area of ​​the airflow channel by more than 50%.

[0043] During the design phase, the stroke of piston 25 can be controlled through a limiting structure to prevent the narrow area 36 from being completely closed, thus maintaining at least a minimum level of unobstructed flow and sustaining the internal circulation airflow. Since the flow control principle of the "external circulation centrifugal fan 45" is the same as that of the "internal circulation centrifugal fan 5," it will not be elaborated upon in this solution.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A box-type air-cooled motor system, characterized in that: Includes a motor housing (9), a rotor shaft (13), a motor stator (11), and a motor rotor (10); a wind box (42), an internal circulation centrifugal fan (5), and an external circulation centrifugal fan (45); the motor stator (11) is coaxially fixed to the inner wall of the motor housing (9); the motor rotor (10) is coaxially fixed to the rotor shaft (13), and the rotor shaft (13) is rotatably engaged with the end caps at both ends of the motor housing (9) through bearings; The internal circulation centrifugal fan (5) and the external circulation centrifugal fan (45) are both coaxially and synchronously installed on the rotor shaft (13); the internal circulation centrifugal fan (5) is located at the front of the stator and rotor cavity inside the motor housing (9); the external circulation centrifugal fan (45) is located at the outer side of the tail end of the motor housing (9); The external circulation centrifugal fan (45) generates external circulation airflow, which carries away the heat in the internal circulation airflow generated by the internal circulation centrifugal fan (5) during operation as it passes through the air box (42). The internal circulation centrifugal fan (5) includes a central fixed sleeve (4), a fan disc (3), centrifugal blades (1) and an arc-shaped air guide ring (2). The centrifugal air inlet (17) is located in the inner ring of the arc-shaped air guide ring (2). The central fixed sleeve (4) is coaxially fixed and locked to the rotor shaft (13) by a locking member. The fan disc (3) is coaxially and integrally connected to the central fixed sleeve (4). The centrifugal blades (1) arranged in a circular array are integrally set between the arc-shaped air guide ring (2) and the fan disc (3). A centrifugal blasting channel (15) is formed between any two adjacent centrifugal blades (1). The centrifugal blade (1) is a hollow plate structure, and the hollow part inside each centrifugal blade (1) is a plate-shaped distal oil tank (22) filled with oil. An annular piston chamber (26) filled with oil is coaxially arranged inside the central fixed sleeve (4). Each plate-shaped distal oil tank (22) is connected to the rear end of the annular piston chamber (26) through the liquid guiding channel (23) in the fan plate (3). A piston (25) is coaxially and movably arranged in the front part of the annular piston chamber (26). The front end of the annular piston chamber (26) is provided with a limiting inner edge (28) that limits and cooperates with the piston (25). A spring (24) that generates a forward thrust on the piston (25) is provided inside the annular piston chamber (26). Each centrifugal blade (1) has a horizontally arranged perforated groove (14a) on both sides of the end away from the axis of the internal circulation centrifugal fan (5); the perforated groove (14a) is sealed with an elastic diaphragm (14), and the edge of the elastic diaphragm (14) is sealed to the surface of the centrifugal blade (1) by a sealing adhesive. In the initial state, the piston (25) is limited by the inner edge (28) under the thrust of the spring (24), so that an initial negative pressure is formed in the annular piston cavity (26). The negative pressure in the annular piston cavity (26) is transmitted to the plate-shaped distal oil reservoir (22) through each liquid guiding channel (23), so that each elastic diaphragm (14) is concave and convex towards the inner side of the plate-shaped distal oil reservoir (22) under the action of negative pressure.

2. The box-type motor air-cooling system according to claim 1, characterized in that: An annular isolation plate (8) is integrally and coaxially disposed inside the motor housing (9). The annular isolation plate (8) is located between the motor rotor (10) and the internal circulation centrifugal fan (5). The part of the annular isolation plate (8) near the axis is an arc-shaped ring lip (7) that conforms to the outer contour of the internal circulation centrifugal fan (5). The arc-shaped ring lip (7) is clearance-fitted with the arc-shaped outer contour of the internal circulation centrifugal fan (5) near the motor rotor (10). An annular air pressure chamber (6) is formed between the front end cover of the motor housing (9) and the annular isolation plate (8) and distributed around the outer periphery of the internal circulation centrifugal fan (5); the outer periphery of the annular air pressure chamber (6) is connected to the front end of the ventilation box (42) through the air guide port (9.1) on the motor housing (9); The tail end of the stator and rotor cavity inside the motor housing (9) forms a negative pressure chamber (12), and the outer ring of the negative pressure chamber (12) is connected to the rear end of the ventilation box (42) through the b air guide (9.2) on the motor housing (9).

3. The box-type motor air-cooling system according to claim 2, characterized in that: The external circulation centrifugal fan (45) is coaxially located inside the external circulation centrifugal fan housing (46). The external circulation centrifugal fan housing (46) is fixed to the air box (42). The tail end of the external circulation centrifugal fan housing (46) is provided with an external circulation air inlet (61) that connects to the outside world. An external circulation air pressure box (43) is fixedly installed at the rear end of the air box (42). The centrifugal air outlet (62) of the external circulation centrifugal air shell (46) is connected to the external circulation air pressure box (43). Several parallel heat exchange air duct arrays (41) pass through the air box (42) laterally. The rear end of the heat exchange air duct array (41) is connected to the external circulation air pressure box (43), and the front end of the heat exchange air duct array (41) is connected to the outside.

4. A box-type motor air-cooling system according to claim 3, characterized in that: The centrifugal inlet (17) is located in the center of the side of the internal circulation centrifugal fan (5) near the motor rotor (10).

5. A box-type motor air-cooling system according to claim 4, characterized in that: When the motor is running, the high-speed rotating internal circulation centrifugal fan (5) creates centrifugal wind pressure in the annular air pressure chamber (6), while a centrifugal negative pressure is created at the centrifugal air inlet (17). The centrifugal negative pressure at the centrifugal air inlet (17) is transmitted to the negative pressure chamber (12) through the air gap between the stator and rotor, so that the negative pressure chamber (12) continuously draws air from the tail end of the air box (42) through the b air guide (9.2), while the gas in the annular air pressure chamber (6) is continuously pressed into the front end of the air box (42) through the a air guide (9.1) under the action of wind pressure, so that the internal circulation gas generated by the internal circulation centrifugal fan (5) continuously flows through the air box (42). At the same time, the external circulation centrifugal fan (45) continuously presses the external air into the external circulation air pressure box (43), so that air pressure is formed in the external circulation air pressure box (43), and the air from the outside in the external circulation air pressure box (43) is continuously discharged to the outside through the heat exchange air duct array (41), thereby forming an external circulation airflow.

6. The box-type motor air-cooling system according to claim 5, characterized in that: When the motor speed is in the high speed range, the oil in the liquid guiding channel (23) flows into the plate-shaped telecentric oil tank (22) under the stronger centrifugal force, thereby changing the negative pressure in the plate-shaped telecentric oil tank (22) to positive pressure. The negative pressure intensity in the annular piston chamber (26) is further enhanced, and the piston (25) moves backward in an adaptive manner, so that a narrow area (36) is formed in the local part of the centrifugal blasting channel (15) between any two adjacent centrifugal blades (1).

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