CN112383191B - A Self-Fan Cooled Axial Flux Motor with External Centrifugal Fan - Google Patents

Abstract

The invention provides a self-fan cooling axial flux motor with an external centrifugal fan. The device comprises a driving end stator, a non-driving end stator, a rotor, a wire outlet box, a rotary transformer, a driving end cover, a non-driving end cover and a cooling system consisting of an external centrifugal fan. The external centrifugal fan is a volute-free centrifugal fan, is positioned on the outer side of the non-drive end cover and is responsible for radial air exhaust. The external centrifugal fan, the rotary transformer rotor and the rotor are coaxially connected. The driving end cover and the non-driving end cover are connected with the shell through screws. The stator of the rotary transformer is fixed on the baffle outside the centrifugal fan, and the outlet box is fixed on the shell through screws. The invention improves the convection heat transfer coefficient of the end surface of the stator iron core, the end surface of the magnetic steel, the surface of the radial fin of the end cover and the inner circumferential surface of the waist-shaped hole of the end cover, and quickly diffuses the heat generated by the stator, the rotor and the bearing into the outside air, thereby improving the heat transfer efficiency.

Description

A Self-Fan Cooled Axial Flux Motor with External Centrifugal Fan

technical field

The invention relates to an integrated starter/engine applied in the fields of emergency power generation and new energy vehicles, in particular to a self-fan cooling axial flux motor integrated with an external centrifugal fan.

Background technique

In the field of emergency power generation and new energy vehicles, the integrated starter/engine are mostly AC permanent magnet synchronous motors, DC motors or AC asynchronous motors with radial flux. Due to the large axial installation size of traditional radial flux motors, the power density and The efficiency is low, and the application in the field of emergency power generation with strict space requirements, portability, and high power density requirements is limited.

Conventional low-power axial flux motors generally use fins on the frame or end caps on both sides to dissipate heat. Under the conditions of large assembly errors of the stator core and end caps, large loads or high speeds, the motor generates a large amount of heat. The heat exchange only by the base fins or the end cover fins often cannot dissipate the heat away in time, which brings great challenges to the insulation and temperature rise of the motor.

SUMMARY OF THE INVENTION

In order to overcome the above shortcomings of the prior art, the purpose of the present invention is to provide a self-fan cooling axial flux motor with an external centrifugal fan. The centrifugal fan is located on the end cover side of the non-drive end and is responsible for exhaust air. The air duct mainly includes two branches, one of which is the air duct branch, which enters the air from the radial fin groove formed by the drive end end cover and the cover plate, and passes through the waist hole of the end cover and the ventilation hole of the rotor back iron. It flows out from the blade of the centrifugal fan or the radial fin groove of the end cover of the non-driving end; the other branch of the air path enters the air from the ventilation hole of the casing, and passes through the air gap between the stator iron core and the rotor magnetic steel of the driving end. The air gap between the non-drive end stator iron core and the rotor magnetic steel flows out from the blades of the centrifugal fan or the radial fin grooves of the non-drive end end cover. In the axial flux motor using this external centrifugal fan cooling scheme, the two air path branches improve the stability of the stator core end face, the magnetic steel end face, the radial fin surface of the end cover and the inner circumferential surface of the waist hole of the end cover. The convective heat transfer coefficient quickly dissipates the heat generated by the motor to the outside air, thereby improving the heat exchange efficiency and achieving a significant increase in power density and torque density.

In order to achieve the above purpose, the technical solution adopted in the present invention is: a self-fan cooling axial flux motor with an external centrifugal fan, which adopts a double stator/single rotor structure, in order to reduce the space harmonics of the stator winding and the magnetic steel Eddy current loss, distributed winding is used for the winding, 18-slot 6-pole or 24-slot 8-pole design is used for the pair of poles and slots, and the rotor magnetic steel is radially segmented and designed with oblique poles in the circumferential direction; the cooling scheme adopts an external centrifugal fan cooling scheme, and centrifugal fan blades Designed as straight blade or backward curved blade; motor includes non-drive end stator, drive end stator, rotor, outlet box, resolver;

The centrifugal fan is located on the side of the end cover of the non-driving end and is responsible for exhausting air; the air path mainly includes two branches, one of which is the air branch, which enters the air from the radial fin groove formed by the end cover and the cover plate of the driving end. Through the waist-shaped hole of the end cover and the ventilation hole of the rotor back iron, it flows out from the blade of the centrifugal fan or the radial fin groove of the end cover of the non-driving end; the other branch of the air path enters the air from the ventilation hole of the casing, and passes through the drive. The air gap air between the stator iron core and the rotor magnetic steel at the end, and the air gap air between the stator iron core and the rotor magnetic steel at the non-driving end flow out from the blades of the centrifugal fan or the radial fin grooves in the end cover of the non-driving end. .

Further, the magnetic circuit runs through the non-drive end stator, the rotor and the drive end stator, and the magnetization scheme of the magnetic steel at the same position on both sides of the rotor back iron is configured according to N-S-N-S.

Further, the non-driving end stator and the driving end stator include a stator iron core, which is formed by winding silicon steel sheets with high magnetic permeability and low loss. The stator core is covered with stator windings, which adopts distributed winding design.

Further, the relative movement of the non-drive end stator and the drive end stator and the rotor is realized by a pair of bearings, the bearings are located on both sides of the intermediate rotor, and can be selected as angular contact bearings or deep groove ball bearings.

Further, the drive end cap has the same structure as the non-drive end cap, the radial spoke-shaped fins distributed along the circumference are designed on the end surface, the adjacent fins form ventilation grooves, and the inner circle of the drive end cap is provided with a rib plate, A waist-shaped hole is designed between the adjacent ribs. The drive end cover is assembled with the cover plate to form a radial ventilation channel.

The principle of the invention is: the self-fan cooling axial flux motor with an external centrifugal fan adopts a double stator/single rotor structure. Winding, rotor magnets are radially segmented; the cooling scheme adopts an external centrifugal fan cooling scheme. The motor includes a non-drive end stator 1 , a drive end stator 2 , a rotor 3 , an outlet box 4 , and a resolver 5 .

The magnetic circuit of the self-fan-cooled axial flux motor with an external centrifugal fan runs through the non-driving end stator 1 , the rotor 3 and the driving end stator 2 .

The non-driving end stator 1 and the driving end stator 2 include a stator iron core 17, and the stator iron core 17 is formed by winding silicon steel sheets with high magnetic permeability and low loss. The stator iron core 17 is covered with a stator winding 15, which adopts a distributed winding design.

A part of the heat generated by the stator core 17 and the windings in the slots of the stator winding 15 is conducted and dissipated to the fins of the drive end cover 18; The inner and outer end windings of the winding 15 dissipate heat by surface convection, dissipating the heat into the surrounding environment.

The relative movement of the non-drive end stator 1 and the drive end stator 2 and the rotor 3 is realized by a pair of bearings, namely the first bearing 23 and the second bearing 25. The first bearing 23 and the second bearing 25 can be selected as angular contact bearings or Deep groove ball bearings.

The outlet box assembly 3 is fixed to the casing 9 by a fourth screw 14 .

The first magnetic steel 27 and the second magnetic steel 29 in the rotor 3 are radially segmented and designed with oblique poles in the circumferential direction in order to reduce the eddy current loss and the tooth harmonics.

The rotor of the resolver 5 is fixed to the motor main shaft 24 by screws, and the stator of the resolver 5 is fixed to the fan baffle 7 by screws 10 to realize accurate rotor position signal detection.

Beneficial effects of the present invention:

In terms of reducing loss, the stator winding adopts 18-slot 6-pole or 24-slot 8-pole distributed winding design, relative to fractional-slot concentrated winding, which reduces the space harmonics of stator winding; rotor magnets are radially segmented and designed with oblique poles in the circumferential direction. , The surface is coated with epoxy resin, which weakens the harmonics of the stator core teeth and reduces the eddy current loss of the magnetic steel.

In terms of improving the heat dissipation capacity, the design with an external centrifugal fan is adopted. The external centrifugal fan mainly realizes the suction of air from the radial ventilation holes of the end cover of the driving end and the ventilation holes on the circumference of the casing, and passes through the ventilation holes of the rotor iron core. The air gap air layer on both sides of the rotor and the radial ventilation grooves of the non-drive end cover are finally exhausted by the centrifugal fan. Under the suction/exhaust action of the centrifugal fan, the outside air flows rapidly in multiple branches on the inner surface of the motor, which improves the heat exchange efficiency of the motor, thereby realizing the cooling of the motor. The motor using this topology and cooling scheme can withstand larger loads, has a more compact structure, and improves the power density and torque density of the motor.

Description of drawings

1 is a cross-sectional view of the overall structure of an axial flux motor according to the present invention, wherein 1 is a non-driving end stator, 2 is a driving end stator, 3 is a rotor, 4 is an outlet box, 5 is a rotary transformer, and 8 is a centrifugal fan, 8a is the blade, 9 is the casing, 9a is the first ventilation hole, 18 is the driving end cover, 18a is the first radial ventilation slot, 18c is the first waist-shaped hole, 35 is the non-driving end cover, 35a is the The second radial ventilation slot, 35c is a second waist-shaped hole.

2 is an exploded view of the overall structure of the axial flux motor of the present invention, wherein 1 is the non-driving end stator, 2 is the driving end stator, 3 is the rotor, 4 is the outlet box, 5 is the resolver, and 6 is the resolver flange , 7 is the fan baffle, 8 is the centrifugal fan, 9 is the casing, 9a is the first ventilation hole, 10 is the first screw, 11 is the second screw, 12 is the sleeve, 13 is the third screw, 14 is the first screw Four screws.

3 is a perspective view of the axial flux motor of the present invention, wherein 8 is a centrifugal fan, 8a is a blade, 8b is an air space, 9 is a casing, 9a is a first ventilation hole, and 18 is a drive end cover, 18a is the first radial ventilation groove, 35 is the non-drive end cover, and 35a is the second radial ventilation groove.

4 is an exploded view of the stator assembly structure of the axial flux motor of the present invention, wherein 15 is a stator winding, 16 is a rib plate, 17 is a stator iron core, 17a is a rectangular groove, 18 is a drive end cover, and 18a is a The first radial ventilation slot, 18b is the first fin, 18c is the first waist-shaped hole, 18d is the rib plate, 19 is the drive end cover, 20 is the fifth screw, and 21 is the sixth screw.

5 is a structural diagram of the end cover of the axial flux motor of the present invention, wherein 18 is the drive end cover, 18a is the radial ventilation slot, 18b is the first fin, 18c is the first waist-shaped hole, and 18d is the first A rib, 35 is a non-driving end cover, 35a is a second radial ventilation slot, 35b is a second fin, 35c is a second waist-shaped hole, and 35d is a second rib.

6 is an exploded view of the rotor assembly structure of the axial flux motor of the present invention, wherein 8 is a centrifugal fan, 8a is a blade, 8b is an air space, 22 is a flange, 23 is a first bearing, 24 is a motor main shaft, and 25 is the second bearing, 26 is the first pressing plate, 27 is the first magnetic steel, 28 is the rotor back iron, 28a is the second ventilation hole, 29 is the second magnetic steel, 30 is the second pressing plate, 31 is the seventh screw, 32 is the shaft retaining ring, 33 is the eighth screw, and 34 is the ninth screw.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings.

The magnetic circuit of the self-fan cooling axial flux motor with an external centrifugal fan runs through the non-driving end stator 1 , the driving end stator 2 and the rotor 3 . The air path adopts an external centrifugal fan cooling scheme. The external centrifugal fan 8 mainly realizes one of the air path branches, and the air enters from the first radial ventilation groove 18a on the drive end cover 18, and flows through the first waist-shaped holes 18c, 18c and 18c of the drive end cover 18. The second ventilation hole 28a of the rotor back iron 28 enters the waist-shaped hole 35c of the non-drive end cover 35; the other branch is sucked air from the first ventilation hole 9a on the circumferential surface of the casing 9 and flows through the rotor 3. The air gap air layer on the two side end faces, the second ventilation hole 28a of the rotor back iron 28, enter the second waist-shaped hole 35c of the non-drive end cover 35, and finally the wind passes through the non-drive end cover 35. The second radial ventilation The air space 8b between the slot 35a and the blades 8a of the centrifugal fan 8 flows out to the outside environment. The 2D profile of the entire air path is shown in Figure 1. Its air inlet/outlet 3D logo is shown in Figure 2.

The self-fan-cooled axial flux motor with an external centrifugal fan adopts a double-stator/single-rotor structure. The rotor 3 is located in the middle of the two non-driving end stators 1 and 2 , and the non-driving end stator 1 , the driving end stator 2 and the casing 9 are fixed by the third screw 13 and the fourth screw 14 respectively. A first ventilation hole 9 a is designed on the circumferential surface of the casing 9 . The centrifugal fan 8 is located outside the non-drive end stator 1 and is coaxially connected to the rotor 3 . The centrifugal fan 8 is designed as a voluteless centrifugal fan, and its blades 8a are designed as straight blades or backward curved blades. The outlet box 4 is fixed to the casing 9 by a fourth screw 14 . The stator of the resolver 5 is fixed to the fan baffle 7 by the first screw 10 and the resolver flange 6, and the rotor is fixed to the motor main shaft 24 by the screw, so as to realize accurate rotor position signal detection. The fan baffle 7 is fixed to the non-driving end cover 35 by the second screw 11 , the sleeve 12 , and the structure diagram of the whole motor is shown in FIG. 3 .

The drive end stator 2 has the same structure as the non-drive end stator 1. Taking the drive end stator 2 as an example, it includes a stator iron core 17, which is made of high magnetic permeability and low loss silicon steel sheets. . The stator slot of the stator iron core 17 is designed with a rectangular groove 17a, and the fifth screw 20 and the rib plate 16 are used to fix the stator iron core 17 to the drive end cover 18. One end face of the driving end cover 18 is designed with a driving end cover plate 19, in order to plan the path of the wind to flow only in the direction of the radial groove. The stator core 17 is wound with stator windings 15, which are designed with 18-slot 6-pole or 24-slot 8-pole distributed winding design. An exploded view of the drive end stator 2 is shown in Figure 4.

The driving end cover 18 is the same as the non-driving end cover 35, and the end surface is designed with first fins 18b distributed along the circumference, and the adjacent fins form first radial ventilation grooves 18a. A first rib plate 18d is provided at the circular position, and a first waist-shaped hole 18c is designed between adjacent rib plates, as shown in FIG. 5 .

The rotor 3 includes a rotor back iron 28 , a first magnetic steel 27 , a second magnetic steel 29 , and a centrifugal fan 8 . The first magnetic steel 27 and the second magnetic steel 29 are located on both sides of the rotor back iron 28 respectively, and are fixed to the rotor back iron 28 by the first pressing plate 26 , the second pressing plate 30 , the eighth screw 33 and the ninth screw 34 . The rotor back iron 28 is designed with a second ventilation hole 28a, which transmits torque with the motor main shaft 24 through a spline pair, and is axially fixed by the flange 22 and the seventh screw 31. The centrifugal fan 8 and the motor main shaft 24 are connected to transmit torque through a key connection, and a shaft retaining ring 32 is used for axially limiting and fixing the centrifugal fan 8. In order to reduce the eddy current loss, the first magnetic steel 27 and the second magnetic steel 29 are designed with radial segments and circumferential inclined poles, as shown in FIG. 6 .

The relative movement of the non-drive end stator 1 and the drive end stator 2 and the rotor 3 is realized by a pair of bearings, namely the first bearing 23 and the second bearing 25. The first bearing 23 and the second bearing 25 can be selected as angular contact bearings or Deep groove ball bearings are located at both ends of the rotor 3, as shown in Figure 6.

Although this specification has illustrated and described specific implementation examples, those skilled in the art will appreciate that various alternative or equivalent implementations may be substituted for the specific implementation examples shown and described without departing from the scope of the invention. Implementation example. This application is intended to cover any adaptations and various specific embodiments of the invention discussed. Accordingly, the present invention is limited only by the claims and their equivalents.

Claims (1)

1. The utility model provides a take external centrifugal fan from cold axial flux motor of fan which characterized in that: a double-stator/single-rotor framework is adopted, in order to reduce the space harmonic of a stator winding and the eddy current loss of magnetic steel, an external centrifugal fan heat dissipation scheme is adopted in a cooling scheme, and blades of a centrifugal fan are designed into straight blades or backward bent blades; the motor comprises a non-driving end stator, a rotor, an outlet box and a rotary transformer;

the magnetic circuit penetrates through the non-drive-end stator, the rotor and the drive-end stator, and the magnetic steel magnetizing schemes at the same positions on two sides of the rotor back iron are configured according to the N-S-N-S;

in particular, the method comprises the following steps of,

the magnetic circuit of the self-fan cold-axial flux motor with the external centrifugal fan penetrates through the non-driving end stator (1), the driving end stator (2) and the rotor (3), the air path adopts a heat dissipation scheme of the external centrifugal fan, the external centrifugal fan (8) mainly realizes one air path branch, air enters from a first radial ventilation groove (18a) on the driving end cover (18), flows through a first waist-shaped hole (18c) of the driving end cover (18) and a second ventilation hole (28a) of the rotor back iron (28), and enters a second waist-shaped hole (35c) of the non-driving end cover (35); the other branch is induced from a first ventilation hole (9a) on the circumferential surface of the machine shell (9), flows through an air gap air layer of two side end surfaces of the rotor (3) and a second ventilation hole (28a) of a rotor back iron (28), enters a second waist-shaped hole (35c) of the non-driving end cover (35), and finally flows out to the external environment through an air area (8b) between a second radial ventilation groove (35a) of the non-driving end cover (35) and a blade (8a) of the centrifugal fan (8);

the self-fan cold axial flux motor with the external centrifugal fan adopts a double-stator/single-rotor framework, a rotor (3) is positioned between two non-drive-end stators (1) and a drive-end stator (2), the non-drive-end stator (1), the drive-end stator (2) and a casing (9) are respectively fixed through a third screw (13) and a fourth screw (14), a first ventilation hole (9a) is designed on the circumferential surface of the casing (9), the centrifugal fan (8) is positioned on the outer side of the non-drive-end stator (1) and is coaxially connected with the rotor (3), the centrifugal fan (8) is designed into a volute-free centrifugal fan, blades (8a) of the centrifugal fan are designed into straight blades or backward-bent blades, an outlet box (4) is fixed on the casing (9) through the fourth screw (14), a stator of a rotary transformer (5) is fixed on a fan baffle (7) through the first screw (10) and a rotary variable flange (6), the rotor is fixed on a motor spindle (24) through screws, accurate rotor position signal detection is achieved, and the fan baffle (7) is fixed with the non-drive-end cover (35) through a second screw (11) and the sleeve (12);

the structure of the driving-end stator (2) is the same as that of the non-driving-end stator (1), the driving-end stator (2) comprises a stator core (17), the stator core (17) is formed by winding silicon steel sheets with high magnetic conductivity and low loss, a rectangular groove (17a) is designed in a stator groove of the stator core (17), the stator core (17) is fixed on a driving-end cover (18) through a fifth screw (20) and a rib plate (16), a driving-end cover plate (19) is designed on one side end face of the driving-end cover (18) to plan that a wind path can only flow in the radial groove direction, a stator winding (15) is wound on the stator core (17), and the design of an 18-groove 6-pole or 24-groove 8-pole distributed winding is adopted;

the driving end cover (18) is the same as the non-driving end cover (35), first fins (18b) distributed along the circumference are designed on the end face, first radial ventilation grooves (18a) are formed by adjacent fins, first rib plates (18d) are arranged at the inner circle position of the driving end cover (18), and first waist-shaped holes (18c) are designed between the adjacent rib plates;

rotor (3) contain rotor back iron (28), first magnet steel (27), second magnet steel (29), centrifugal fan (8), wherein first magnet steel (27), second magnet steel (29) are located the both sides of rotor back iron (28) respectively, use first clamp plate (26), second clamp plate (30), eighth screw (33), ninth screw (34) to fix to rotor back iron (28), rotor back iron (28) design has second ventilation hole (28a), with motor spindle (24) through the vice transmission moment of torsion of spline, and use flange (22), seventh screw (31) axial fixity, centrifugal fan (8) and motor spindle (24) pass through key-type connection transmission moment of torsion, and use for the axial retaining ring (32) to be used for centrifugal fan (8) axial limit fixed, in order to reduce its eddy current loss, first magnet steel (27), second magnet steel (29) adopt radial segmentation, designing a circumferential oblique pole;

the relative motion of the non-driving end stator (1), the driving end stator (2) and the rotor (3) is realized through a pair of bearings, namely a first bearing (23) and a second bearing (25), wherein the first bearing (23) and the second bearing (25) are selected to be angular contact bearings or deep groove ball bearings and are positioned at two ends of the rotor (3).

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