Circulating air cooling structure of axial permanent magnet motor

Abstract

An axial permanent magnet motor circulating air cooling structure is characterized in that an airflow duct is arranged in a rotating shaft of an axial permanent magnet motor, one end, in the rotating shaft, of the airflow duct is communicated with the interior of a rotor, air wings are arranged on the rotor of the axial permanent magnet motor, and exhaust holes are formed in a shell of the axial permanent magnet motor. The rotation kinetic energy of an axial permanent magnet motor rotor is utilized to generate air volume and form air pressure flow when the rotor rotates, so that external air enters an air gap between a stator and the rotor, flows through the surface of the stator and the surface of the rotor along the air gap and then returns to the back surface of the rotor to be discharged, circulating air flow is formed for heat exchange, and heat in the motor is released. The purpose of naturally cooling heat in the motor is achieved. On the basis that the internal structure of the axial permanent magnet motor is not changed, the cooling efficiency of the motor is improved, and the production and maintenance cost is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of method and structure for the cooling of axial permanent magnet motor, belong to axial permanent magnet motor cooling technical field. BACKGROUND

[0002] The basic structure of axial permanent magnet motor is described in Figure 3 , comprising shell 11, stator 6, rotor and shaft 5, rotor is composed of two rotor yokes 9 (two metal plates) and the patch magnetic pole 8 being arranged in the inner side of rotor yoke 9, when two rotor yokes 9 relatively move in alternating magnetic field, electromagnetic force is generated between the two and they are attracted to each other. The shaft 5 is installed in the shell 11 through bearing, the shaft 10 is connected with the rotor yoke 9 through the flange on it, the shaft 5 one end extends out of the shell 11, the stator 6 and the rotor yoke 9 are arranged in the shell 11, the stator 6 is between the two rotor yokes 9, and there is air gap between them. Mechanical energy is converted from electrical energy by generating magnetic field between the stator 6 and the rotor yoke 9. When running, the rotor yoke 9 rotates, copper loss, iron loss and eddy current loss, etc. will be generated, and the loss is finally converted into heat. The higher the power of the motor, the higher the temperature rise, and the motor needs to be cooled to reduce the temperature to affect the stator and the rotor permanent magnet.

[0003] The motor cooling method includes natural cooling, air cooling, water cooling and oil-gas mixed cooling. Different cooling methods have different structural complexities, maintenance costs and fault points.

[0004] Because the axial permanent magnet motor adopts a closed process, the generated heat is not easy to discharge, and poor heat dissipation is a problem that needs to be solved urgently for the motor.

[0005] In the prior art, the axial permanent magnet motor adopts external auxiliary cooling air cooling method or external circulation cooling water channel method. As shown in Figure 1 , an external fan 1 is used to forcibly blow cold air into the motor interior for heat dissipation. This method installs the fan on the shaft of the motor, which not only increases the axial length H of the motor, but also increases the additional fan loss and reduces the efficiency of the motor. As shown in Figure 2 , the cooling water channel 2 needs to be constructed in the shell, and the cooling circulation system 3 provides circulating liquid for the cooling water channel 2. This method not only increases the cost of the motor, but also increases the cost of regular maintenance and replacement of cooling liquid, and has complex process, low efficiency and high cost. UTILITY MODEL CONTENTS

[0006] The utility model provides a circulating air cooling method for axial permanent magnet motor, which has high cooling efficiency, can reduce production cost and maintenance cost, and solves the problems of the prior art.

[0007] The axial permanent magnet motor circulating air cooling structure adopts the following technical scheme:

[0008] The structure is that an airflow air duct is arranged in the rotating shaft of the axial permanent magnet motor, the airflow air duct is communicated with the inside of the rotor at one end in the rotating shaft, air fins are arranged on the rotor of the axial permanent magnet motor, and exhaust holes are arranged on the shell of the axial permanent magnet motor.

[0009] The shape of the airflow air duct is a round hole, a square hole, a triangular hole or other special-shaped holes.

[0010] The airflow air duct is communicated with the inside of the rotor by being provided with a radial through hole on the rotating shaft.

[0011] The air fins are distributed on the outside of the rotor.

[0012] When the rotor rotates, the air fins on the rotor rotate to generate air volume, form air pressure flow, generate negative pressure at the inner end of the airflow air duct, and make the outside air enter the airflow air duct; the cold air flow enters the air gap formed by the stator and the rotor, flows through the surfaces of the stator and the rotor along the air gap, exchanges heat; the air flow reaches the outside of the air gap and then returns to the back of the rotor, forms rotating air flow, passes through the gap between the back of the rotor and the shell, and finally the hot air is discharged from the exhaust holes on the shell, forms a circulating air flow path, releases the heat in the motor to the outside, realizes the function of heat exchange between the heat in the motor and the cold air outside, achieves the purpose of naturally cooling the heat in the motor, guarantees the normal operation of the motor, and solves the problem that the structure of the axial permanent magnet motor is not easy to dissipate heat.

[0013] The axial permanent magnet motor circulating air cooling structure has the advantages that the air fins distributed on the rotor form rotating air flow in the motor, the air flow is effectively introduced, the cooling air flow flows through the surfaces of the stator and the rotor to the maximum extent, the heat generated by the stator and the rotor is taken out of the body, the cooling effect of the axial permanent magnet motor is good, the air speed is improved, the heat dissipation speed with the shell is accelerated, the mechanical strength of the rotor is also enhanced by increasing the air fins on the rotor, the consistency of the air gap is guaranteed, the consistency of the air gap magnetic distribution and the motor efficiency are improved, the material removal position during dynamic balancing is increased, the normal operation of the motor is guaranteed, the problem that the structure of the axial permanent magnet motor is not easy to dissipate heat is solved, and the surface temperature of the motor with the structure is about 15 DEG C lower than that of the motor without the structure.

[0014] The axial permanent magnet motor circulating air cooling structure has the advantages that the heat dissipation effect is optimized to the maximum extent, the cooling efficiency in the motor is improved on the basis of not changing the internal structure of the axial permanent magnet motor, the production cost and the maintenance cost are reduced, the economic benefit and the performance benefit of the axial permanent magnet motor are improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is the schematic diagram of the external air cooling structure of the prior axial permanent magnet motor.

[0016] Figure 2 is the schematic diagram of the external circulation cooling structure of the prior axial permanent magnet motor.

[0017] Figure 3 is the schematic diagram of the circulation air cooling structure of the axial permanent magnet motor in the utility model.

[0018] Figure 4 is the sectional schematic diagram of the cooling structure.

[0019] In the drawing: 1. external fan, 2. external cooling water channel, 3. cooling circulation system, H. motor external dimension;

[0020] 4. exhaust hole, 5. rotating shaft, 6. stator, 7. air flow channel, 8. magnetic pole, 9. rotor yoke, 10. air fin, 11. shell, 12. radial through hole. DETAILED DESCRIPTION

[0021] The utility model axial permanent magnet motor circulation air cooling structure, see Figure 3 and Figure 4 , specifically is the exhaust hole 4 that sets up on the shell 11. The air flow channel 7 is set up in the rotating shaft 5, and the outer end of the air flow channel 7 is communicated with the atmosphere, and the inner end of the air flow channel 7 is provided with the radial through hole 12, and its position is between the upper and lower rotor yoke 9, so that the external airflow can enter the rotor interior. The air fin 10 is set up on the rotor yoke 9, and the air fin 10 is distributed on the outside of the rotor yoke 9, and the air fin 10 can be various shapes that can produce air volume, not limited to strip shape, including various curve shapes. The air fin 10 is not limited to the convex structure, and can include the air groove (concave structure) on the rotor yoke 8. Through the air fin 10 on the rotor yoke 9, the rotating airflow is formed in the motor interior, the wind speed is improved, and the speed of heat dissipation is accelerated. Figure 3 The arrow in the figure represents the airflow direction. The shape of the air flow channel 7 can be a round hole, a square hole, a triangular hole or other special-shaped hole.

[0022] The core of the structure is that the effective import of airflow is effectively flowed through the surface of the stator 6 and the rotor yoke 9 through the air fin 10 distributed on the rotor yoke 9, the heat generated by the stator and the rotor is taken out of the body, and the cooling of the axial permanent magnet motor has good effect.

[0023] In addition, the air fin 10 is added on the rotor yoke 8, the mechanical strength of the rotor yoke 8 is also enhanced, the consistency of the air gap is ensured, the consistency of the air gap magnetic distribution and the motor efficiency are improved, and the material removal position during dynamic balancing is increased.

[0024] The air volume (cooling air volume) Q generated by the air fin 10 is calculated according to the following process.

[0025] Q = V * A; wherein: Q is the air volume, V is the air speed, and A is the air duct cross-sectional area.

[0026] The heat dissipation amount is calculated by the formula: P = a (Ti - To) F; wherein: P is the heat dissipation amount, unit: w; Ti is the surface temperature of the heat dissipation surface, ℃; To is the external environment temperature, ℃; F is the area of the heat dissipation surface, m 2 ; and a is the comprehensive heat exchange coefficient, w / (℃×m 2 ).

[0027] The weight of air is the product of density and volume, and the volume of air is calculated by CMM or CFM (i.e. air volume), so the weight of air W = Q / 60*1185 (Q takes CMM), which is the weight of air per second. After substituting into the above formula and conditions and further simplifying, the following formula can be obtained:

[0028] Q = 1.8 * P / △Tc; wherein: Q is the air volume, P is the heat dissipation amount, and △Tc = Ti - To is the temperature difference.

[0029] In the case that other parameters of the motor are unchanged, the air volume Q is increased by the air fin 10 on the rotor yoke 9, the heat dissipation capacity is increased, and the heat dissipation efficiency is improved.

[0030] The above axial permanent magnet motor circulating air cooling structure, through the organic combination of the motor rotor yoke 8 and the air fin 10, utilizes the rotational kinetic energy of the motor rotor yoke 9. According to aerodynamics, when the rotor yoke 9 rotates, the air fin 10 thereon rotates to generate air pressure, forming air pressure flow, generating negative pressure at the inner end of the airflow duct 7, so that the outside air flows into the airflow duct 7 from the outside. The cold airflow enters the air gap composed of the stator 6 and the rotor yoke 9 through the airflow duct 7, forming two airflows flowing along the surface of the stator 6 and the surface of the rotor yoke 8 respectively, and exchanging heat. The airflow reaches the maximum outer diameter of the rotor yoke 8 and then returns to the back surface of the rotor yoke 8, forms a rotating airflow, and then continues to flow to the exhaust hole 4 on the outer shell 11, and finally the hot air is discharged from the exhaust hole 4, releasing the heat in the motor to the outside, forming a circulating airflow path, achieving the function of rapidly exchanging heat between the heat in the motor and the cold air outside, achieving the purpose of naturally cooling the heat in the motor, ensuring the normal operation of the motor, and solving the problem that the structure of the axial permanent magnet motor is not easy to dissipate heat.

[0031] Through testing, the surface temperature of the motor with this structure is about 15℃ lower than that of the motor without this structure.

Claims

1. An axial permanent magnet motor circulating air cooling structure, characterized in that, The air flow channel is communicated with the inside of the rotor at one end in the rotating shaft of the axial permanent magnet motor, the air fin is arranged on the rotor of the axial permanent magnet motor, and the exhaust hole is arranged on the shell of the axial permanent magnet motor.

2. The axial flux permanent magnet machine circulating air cooling structure according to claim 1, characterized in that, The shape of the air flow channel is a round hole, a square hole or a triangular hole.

3. The axial flux permanent magnet machine circulating air cooling structure according to claim 1 or 2, characterized in that, The air flow channel is communicated with the inside of the rotor by arranging a radial through hole on the rotating shaft.

4. The axial flux permanent magnet machine circulating air cooling structure according to claim 1, characterized in that, The air fins are distributed on the outside of the rotor.

5. The axial flux permanent magnet machine circulating air cooling structure according to claim 1, characterized in that, The air fins include long strip shape and curved shape.

6. The axial flux permanent magnet machine circulating air cooling structure according to claim 1, characterized in that, The air fins are in convex structure or concave structure.

Images