CN112383192A

CN112383192A - Self-cooling axial flux motor with built-in axial flow fan

Info

Publication number: CN112383192A
Application number: CN202011312321.7A
Authority: CN
Inventors: 陈起旭; 王群京; 李国丽; 周嗣理; 钱喆
Original assignee: Anhui University
Current assignee: Anhui University
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2021-02-19
Anticipated expiration: 2040-11-20
Also published as: CN112383192B

Abstract

The invention provides a self-fan cooling axial flux motor with a built-in axial flow fan, which adopts a single-stator/double-rotor topology. The axial flow fan is positioned between the two rotors and fixed on the shaft. The air path enters from the outer circumferential vent hole on one side of the shell, passes through air gap air between the non-drive-end rotor magnetic steel and the stator core and air gap air between the axial flow fan and the drive-end rotor magnetic steel and the stator core, and flows out from the outer circumferential vent hole on the other side of the shell. On the one hand, the axial fan air cooling scheme of rotor has improved the convective heat transfer coefficient of magnet steel terminal surface, rotor back iron terminal surface, end cover terminal surface and stator wheel hub inner circumferential face. By adopting the air cooling scheme of the axial flow fan integrated in the motor, the heat generated by the motor can be quickly diffused into the outside air, so that the heat exchange efficiency is improved, and the remarkable improvement of the power density and the torque density is realized.

Description

Self-cooling axial flux motor with built-in axial flow fan

Technical Field

The invention relates to an integrated starting/engine applied to the fields of emergency power generation and new energy automobiles, in particular to a self-cooling axial flux motor with a built-in axial flow fan.

Background

The motors in the fields of emergency power generation and new energy automobiles are mostly alternating-current permanent magnet synchronous motors or alternating-current asynchronous motors with radial magnetic fluxes, and because the axial installation size of the traditional radial magnetic flux motor is large, the power density and the efficiency are low, the application of the motor in the occasions with strict space requirements and high power density requirements is limited.

A conventional low-power axial flux motor generally adopts a fin heat dissipation scheme on a base or end covers on two sides, and under the working conditions of large assembly error, large load or high rotating speed of a stator core and the end covers, a large amount of heat generated by the motor is only transferred by fins or water cooling, so that the heat cannot be dissipated and taken away in time, and great challenges are brought to insulation and temperature rise of the motor.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a self-fan cold axial flux motor with a built-in axial flow fan. The axial flow fan is positioned between the two rotors and fixed on the shaft. The air path enters from the outer circumferential vent hole on one side of the shell, passes through air gap air between the non-drive-end rotor magnetic steel and the stator core and air gap air between the axial flow fan and the drive-end rotor magnetic steel and the stator core, and flows out from the outer circumferential vent hole on the other side of the shell. On the one hand, the axial fan air cooling scheme of rotor has improved the convective heat transfer coefficient of magnet steel terminal surface, rotor back iron terminal surface, end cover terminal surface and stator wheel hub inner circumferential face. By adopting the air cooling scheme of the axial flow fan integrated in the motor, the heat generated by the motor can be quickly diffused into the outside air, so that the heat exchange efficiency is improved, and the remarkable improvement of the power density and the torque density is realized.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a self-fan cold axial flux motor with a built-in axial flow fan adopts a single stator/double rotor framework, adopts a four-layer double three-phase fractional slot concentrated winding design with 12 slots and 10 poles or 12 slots and 14 poles, and reduces stator winding space harmonic waves; the rotor magnetic steel adopts a radial segmented design, and epoxy resin is coated on the surface of the rotor magnetic steel, so that the eddy current loss of the magnetic steel is reduced. The cooling scheme adopts a built-in axial flow fan heat dissipation scheme; the motor comprises a stator, a drive end rotor, a non-drive end rotor, a rotary transformer and an outlet box;

the axial flow fan is positioned between the two rotors and fixed on the shaft; the air path enters from the outer circumferential vent hole on one side of the shell, passes through air gap air between the non-drive-end rotor magnetic steel and the stator core and air gap air between the axial flow fan and the drive-end rotor magnetic steel and the stator core, and flows out from the outer circumferential vent hole on the other side of the shell.

Furthermore, the magnetic circuit penetrates through the non-drive-end stator, the rotor and the drive-end stator, and the magnetic steel at the same position of the rotors at the two ends is magnetized and configured according to N-S-N-S.

Furthermore, the stator comprises a stator core, wherein the stator core is designed to be a core-free yoke part and is formed by radially laminating high-permeability and low-loss silicon steel sheets; the inner and outer circumferential surfaces of the stator core are provided with fan-shaped pressing plates, the fan-shaped pressing plates and the stator core on two sides are pressed and fixed along the radial direction by rivets, the stator core is sleeved with a stator winding, and the design of a concentrated winding is adopted.

Furthermore, the heat generated by the stator core and the windings in the slots of the stator windings realizes that the outside air enters from the ventilation holes at the non-driving end side of the outer circumference surface of the casing under the air suction/exhaust action of the built-in axial flow fan, passes through the axial flow fan through the air gap air layers at the two sides of the rotor at the non-driving end, passes through the air gap air layers at the two sides of the rotor at the driving end, and finally exhausts from the ventilation holes at the driving end side of the outer circumference of the casing to diffuse the heat into the surrounding environment.

Further, the relative movement of the stator and the two rotors is realized through a pair of bearings, the two bearings are distributed on the outer sides of the two rotors, and the two bearings can be selected from angular contact bearings, deep groove ball bearings or crossed roller bearings.

The principle of the invention is as follows: the self-fan cold axial flux motor with the built-in axial flow fan adopts a single-stator/double-rotor framework, in order to reduce the length of the end part of a stator winding, the winding adopts a concentrated winding, and rotor magnetic steel is radially segmented to reduce the eddy current loss of the magnetic steel; the cooling scheme adopts a built-in axial flow fan heat dissipation scheme. The motor comprises a stator 1, a drive end rotor 2b, a non-drive end rotor 2a, a rotary transformer 3 and an outlet box 4.

The magnetic circuit of the self-cooling axial flux motor with the external centrifugal fan penetrates through the stator 1, the non-driving end rotor 2a and the driving end rotor 2 b.

The stator 1 comprises a stator core 23, wherein the stator core 23 is designed to be a core-free yoke part and is formed by radially laminating high-permeability and low-loss silicon steel sheets. The stator core 23 is sleeved with a stator winding 21, and a concentrated winding design is adopted.

The heat generated by the stator core 24 and the in-slot windings of the stator winding 21 is induced/exhausted by the built-in axial flow fan, so that the air is induced from the air vent on one side of the casing 17, passes through the air gap air layer on the two sides of the non-drive-end rotor 2a and the drive-end rotor 2b, is exhausted from the air vent on the other side of the casing 17, and finally, the heat is diffused to the surrounding environment.

The relative movement of the stator 1 and the rotor 2 is realized by a pair of bearings, namely a first bearing 36 and a second bearing 46, and the first bearing 36 and the second bearing 46 can be selected as angular contact bearings or deep groove ball bearings.

The outlet box assembly 4 is secured to the housing 17 by second screws 15.

The drive end magnetic steel 39 and the non-drive end magnetic steel 43 in the rotor 2 adopt a radial segmented design in order to reduce the eddy current loss.

The rotor of the rotary transformer 3 is fixed on the motor spindle 37 through screws, and the stator of the rotary transformer 3 is fixed on the non-drive end cover 9 through third screws 16, so that accurate rotor position signal detection is realized.

The invention has the beneficial effects that:

(1) from the aspect of reducing loss, the stator winding adopts a 12-slot 10-pole or 12-slot 14-pole double three-phase four-layer fractional slot concentrated winding design, so that the space harmonic of the stator winding is reduced; the rotor magnetic steel adopts a radial segmented design, and epoxy resin is coated on the surface of the rotor magnetic steel, so that the eddy current loss of the magnetic steel is reduced.

(2) In the aspect of improving the heat dissipation capacity, the design of the built-in axial flow fan is adopted, the built-in axial flow fan mainly realizes that outside air enters from a vent hole on one side of the casing, passes through an air gap layer on two sides of one rotor on the non-driving end, passes through the axial flow fan, then passes through an air gap layer on two sides of the other rotor on the driving end, exhausts from a vent hole on the other side of the casing, and finally diffuses heat to the surrounding environment. Under the effect of air suction/exhaust of the axial flow fan, external air rapidly flows in multiple branches on the inner surface of the motor, so that the heat exchange efficiency of the motor is improved, and the cooling of the motor is realized. The motor adopting the topology and the cooling scheme can bear larger load, has more compact structure and improves the power density and the torque density of the motor.

Drawings

Fig. 1 is a cross-sectional view of the general structure of an axial-flux motor of the present invention, where 1 is a stator, 2a is a non-drive-end rotor, 2b is a drive-end rotor, 3 is a resolver, 4 is an outlet box assembly, 6 is a drive-end cover, 9 is a non-drive-end cover, 17 is a housing, 17a is a first ventilation hole, 17b is a second ventilation hole, and 42 is an axial-flow fan.

Fig. 2 is an exploded view of the overall structure of the axial flux motor of the present invention, where 1 is a stator, 2 is a rotor, 2a is a non-drive-end rotor, 2b is a drive-end rotor, 3 is a resolver, 4 is an outlet box assembly, 5 is a drive-end bearing cover, 6 is a drive-end cover, 7 is a first hole retainer, 8 is a second hole retainer, 9 is a non-drive-end cover, 10 is a resolver flange, 11 is a first screw, 12 is a first nut, 13 is a stud, 14 is a second nut, 15 is a second screw, and 16 is a third screw.

Fig. 3 is an axial view of an axial-flux motor according to the present invention, in which 17 denotes a housing, 17a denotes a first ventilation hole, and 17b denotes a second ventilation hole.

Fig. 4 is an exploded view of a stator assembly structure of an axial flux motor according to the present invention, where 17 is a housing, 17a is a first ventilation hole, 17b is a second ventilation hole, 17c is a rectangular wire outlet, 17d is an annular boss, 17e is a trapezoidal recessed platform, 18 is a first annular retaining ring, 19 is a second annular retaining ring, 20 is a stator hub, 20a is a rib plate, 20b is a hub, 21 is a stator winding, 22 is epoxy resin, 23 is a first sector pressing plate, 24 is a stator core, 25 is a second sector pressing plate, 26 is a third annular retaining ring, 27 is a fourth annular retaining ring, 28 is a fifth annular retaining ring, 29 is a fourth screw, 30 is a fifth screw, 31 is a sixth screw, 32 is a rivet, 33 is a seventh screw, 34 is an eighth screw, and 35 is a ninth screw.

Fig. 5 is an exploded view of a rotor assembly structure of an axial flux motor according to the present invention, where 36 is a first bearing, 37 is a motor spindle, 38 is a driving-end pressing strip, 39 is driving-end magnetic steel, 40 is a spindle, 41 is a shaft retainer, 42 is an axial fan, 43 is non-driving-end magnetic steel, 44 is a non-driving-end pressing strip, 45 is non-driving-end rotor back iron, and 46 is a second bearing.

Detailed Description

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

The magnetic circuit of the self-cooling axial flux motor with the built-in axial flow fan penetrates through the stator 1, the driving end rotor 2b and the non-driving end rotor 2 a. The wind path adopts a heat dissipation scheme of a built-in axial flow fan. The built-in axial flow fan 42 mainly realizes an air passage that draws air from the non-drive end side ventilation hole of the casing 17, flows through the air gap air layers on the two side end surfaces of the non-drive end rotor 2a, and enters the air inlet of the axial flow fan 42. And enters air gap air layers at two sides of the driving end rotor 2b, finally flows out of the driving end second ventilation hole 17b of the machine shell 17, and exhausts air to the surrounding air. Fig. 1 shows a cross section of the entire air passage 2D. The air inlet/outlet 3D mark is shown in figure 2.

The self-cooling axial flux motor with the built-in axial flow fan adopts a single-stator/double-rotor structure. The stator 1 is positioned between the non-driving end rotor 2a and the driving end rotor 2b, and the non-driving end cover 9, the driving end cover 6 and a shell 17 in the stator 1 are fixed through a first nut 12, a stud 13 and a second nut 14. The resolver flange 10 and the drive end bearing outer cover 5 are used for fixing the outer sides of the bearing outer rings at two ends through third screws 16 and first screws 11 respectively. The first and second hole stoppers 7 and 8 are used for fixing the inner sides of the bearings at both ends. Outlet box assembly 4 is secured to housing 17 by second screws 15. The stator of the resolver 3 is fixed to the non-drive-end cap 9 by the third screws 16, and the rotor of the resolver 3 is fixed to the motor spindle 37 by screws, enabling accurate rotor position signal detection. The structure of the whole motor is shown in fig. 3.

The stator 1 comprises a stator core 24, and the stator core 24 is formed by radially laminating silicon steel sheets with high magnetic conductivity and low loss. The inner and outer circumferential surfaces of the stator core 24 are provided with a first sector pressing plate 23 and a second sector pressing plate 25, and the stator core 24, the first sector pressing plate 23 and the second sector pressing plate 25 are fastened along the radial direction through rivets 32. The stator winding 21 is wound on the stator core 24, and the stator core 24 wound with the stator winding 21 is placed between the adjacent rib plates 20a of the stator hub 20 by adopting a centralized winding design and is finally fixed on the machine shell 17. The circumferential surface of the housing 17 is designed with a first ventilation hole 17a, a second ventilation hole 17b and an outlet hole 1 c. Since the stator core 24 and the stator winding 21 are fixed to the stator hub 20, the fitting relationship therebetween and the fixing manner with the housing 17 are mainly described below. And the second annular retainer ring 19 and the third annular retainer ring 26 are pressed against two end faces of the second sector pressure plate 25 by using fifth screws 30 and eighth screws 34 at two sides of the inner ring of the stator 1 and are fixed on rib plates 20a of the stator hub 20. And the fourth annular retainer rings 18 and the fourth annular retainer rings 27 are pressed against the two end surfaces of the first fan-shaped pressure plate 23 by using fourth screws 29 and eighth screws 34 at two sides of the outer ring of the stator 1 and are fixed on rib plates 20a of the stator hub 20. The rib plate 20a of the stator hub 20 is fixed to the annular boss 17d of the housing 17 by the sixth screw 32. The circumferential position of the rib plate 20a of the stator hub 20 is fixed by the trapezoidal recessed land 17e of the housing 17. The axial direction limitation of the rib plate 20a of the stator hub 20 is realized by the fifth annular retainer ring 28 and the annular boss 17d of the housing 17. Epoxy resin 22 is filled in a gap between the inner end winding of the stator winding 21 and the hub 20b of the stator hub 20, thereby improving the heat transfer coefficient and the axial sealing property between the inner end winding of the stator winding 21 and the stator hub 20. The exploded view of the stator 1 is shown in fig. 5.

The rotor 2 includes a non-driving rotor 2a, a driving-end rotor 2b and an axial flow fan 42. The non-driving end rotor comprises a non-driving end rotor back iron 45, non-driving end magnetic steel 43 and a non-driving end pressing strip 44, and the non-driving end magnetic steel 43 is fixed on the non-driving end rotor back iron 45 by using a screw and the non-driving end pressing strip 44; the driving end rotor comprises a driving end rotor back iron 37, a driving end magnetic steel 39 and a driving end pressing strip 38, and the driving end magnetic steel 39 is fixed on the driving end rotor back iron 37 through screws and the driving end pressing strip 38. The shaft retainer 41 is used for axial limiting of the non-drive end rotor back iron 45. The axial fan 42 is connected to the main shaft 40 via a spline pair to transmit torque. In order to reduce the eddy current loss, the non-drive-end magnetic steel 43 and the drive-end magnetic steel 39 are designed in a radial segmented manner, as shown in fig. 5.

The relative movement of the stator 1 with the non-drive end rotor 2a and the drive end rotor 2b is realized by a pair of bearings, namely a first bearing 36 and a second bearing 46, wherein the first bearing 36 and the second bearing 46 can be selected to be angular contact bearings or deep groove ball bearings and are respectively positioned at the outer sides of the non-drive rotor 2a and the drive end rotor 2 b. As shown in fig. 5.

While specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or embodiments of the invention discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.

Claims

1. The utility model provides a take built-in axial fan cold axial flux motor of certainly of axial fan which characterized in that: a single stator/double rotor framework is adopted, and a four-layer double three-phase fractional slot concentrated winding design with 12 slots and 10 poles or 12 slots and 14 poles is adopted, so that the space harmonic of a stator winding is reduced; the rotor magnetic steel adopts a radial segmented design, and epoxy resin is coated on the surface of the rotor magnetic steel, so that the eddy current loss of the magnetic steel is reduced; the cooling scheme adopts a built-in axial flow fan heat dissipation scheme; the motor comprises a stator, a drive end rotor, a non-drive end rotor, a rotary transformer and an outlet box;

2. The self-cooling axial flux electric machine with an internal axial flow fan according to claim 1, characterized in that: the magnetic circuit penetrates through the non-drive-end stator, the rotor and the drive-end stator, and the magnetic steel at the same position of the rotors at the two ends is configured according to N-S-N-S magnetizing.

3. The self-cooling axial flux electric machine of claim 1, wherein the self-cooling axial flux electric machine comprises: the stator comprises a stator iron core, the stator iron core is designed to be a yoke part without the iron core and is formed by radially laminating silicon steel sheets with high magnetic conductivity and low loss; the inner and outer circumferential surfaces of the stator core are provided with fan-shaped pressing plates, the fan-shaped pressing plates and the stator core on two sides are pressed and fixed along the radial direction by rivets, the stator core is sleeved with a stator winding, and the design of a concentrated winding is adopted.

4. The self-cooling axial flux electric machine with an internal axial flow fan according to claim 1, characterized in that: the heat generated by the stator core and the windings in the slots of the stator windings realizes that the outside air enters from the ventilation holes at the non-driving end side of the outer circumference surface of the casing under the air suction/exhaust action of the built-in axial flow fan, passes through the axial flow fan through the air gap air layers at the two sides of the rotor at the non-driving end, passes through the air gap air layers at the two sides of the rotor at the driving end, and finally exhausts from the ventilation holes at the driving end side of the outer circumference of the casing to diffuse the heat to the surrounding environment.

5. The self-cooling axial flux electric machine with an internal axial flow fan according to claim 1, characterized in that: the relative movement of the stator and the two rotors is realized through a pair of bearings, the two bearings are distributed on the outer sides of the two rotors, and the two bearings can be selected from angular contact bearings, deep groove ball bearings or crossed roller bearings.