WO2017148415A1

WO2017148415A1 - External rotor motor

Info

Publication number: WO2017148415A1
Application number: PCT/CN2017/075444
Authority: WO
Inventors: 朱涛
Original assignee: 罗伯特·博世有限公司; 朱涛
Priority date: 2016-03-02
Filing date: 2017-03-02
Publication date: 2017-09-08
Also published as: CN107154697A; CN107154697B

Abstract

An external rotor motor (1) comprises: a shaft (10); a stator (20), surrounding the shaft and fixedly disposed on the shaft (10), wherein, the stator comprises a yoke (21) and a support portion (23) located at a radial inner side of the yoke, a plurality of winding teeth (211) are formed at the yoke, each of the winding teeth has wound thereon a winding (213), and a plurality of openings (233) are formed on the support portion; a rotor (30), surrounding the shaft and disposed at a radial outer side of the stator; a first end cover (40), rotatably supported on the shaft; a second end cover (50) rotatably supported on the shaft, wherein the first end cover, the second end cover and at least a part of the rotor together define an internal space of the outer rotor motor; and airflow driving mechanisms (45, 41, 51), for causing air to pass through gaps around the windings and through the plurality of openings so as to circulate in the internal space. The structure enhances the heat dissipation effect of the outer rotor motor.

Description

Outer rotor motor

Technical field

This invention relates to electric machines, and more particularly to outer rotor type electric machines.

Background technique

The outer rotor type motor has a wide range of uses due to its compact structure. In particular, with the emphasis on environmental protection, outer rotor type motors such as hub motors are increasingly used in electric vehicles such as electric scooters, electric bicycles, electric motorcycles or electric vehicles. The biggest feature of the hub motor is that the power, transmission and braking devices can be integrated into the hub, thus greatly simplifying the mechanical structure of the electric vehicle. However, due to the compact structure of the hub motor, the heat dissipation problem of the hub motor becomes very important. The cooling performance of the hub motor often becomes a bottleneck that limits its rated power. If the cooling performance of the hub motor can be effectively increased, the hub motor can be allowed to have a larger rated power.

Conventional cooling methods for hub motors include natural air cooling and forced liquid cooling. For natural air cooling, heat is typically dissipated into the air by natural convection between the air and the surfaces of the two end caps. For forced liquid cooling, pumps and radiators are often required to dissipate the heat generated by the hub motor. When an outer rotor type hub motor is used, since the winding is supported on a stator located inside the hub motor, a heat transfer path for winding heat dissipation needs to pass through the shaft and through an air gap formed between the stator and the end cover, which results in winding There is a high thermal resistance between the external environment and the external environment. Therefore, it is desirable to reduce the aforementioned thermal resistance to improve the performance of the hub motor.

Therefore, there is a need to improve the existing outer rotor type motor.

Summary of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to overcome at least one of the above-mentioned deficiencies of the prior art and to provide an improved outer rotor type motor in which the heat dissipation effect of the outer rotor type motor can be remarkably improved.

To this end, according to an aspect of the present invention, an outer rotor type motor is provided, comprising:

axis;

a stator fixedly disposed on the shaft about the shaft, wherein the stator includes a yoke portion formed by stacking a plurality of stator core pieces together and located radially inward of the yoke portion for The yoke portion fixedly supports a support portion on the shaft, the yoke portion is formed with a plurality of winding teeth radially outward, and a winding is wound around each of the winding teeth, and the support portion is formed with a plurality of Opening

a rotor disposed radially outward of the stator about the shaft;

a first end cap rotatably supported on the shaft by a first bearing and fixedly coupled to the rotor;

a second end cap rotatably supported on the shaft by a second bearing and fixedly coupled to the rotor, the first end cap and the second end cap co-defining with at least a portion of the rotor The internal space of the outer rotor type motor;

An air flow drive mechanism for urging airflow through a gap around the winding and circulating the plurality of openings in the interior space.

Preferably, the air flow driving mechanism is at least one of: a centrifugal fan located on an inner surface of one of the first end cover and the second end cover; disposed inside the first end cover a first baffle surface and arranged to direct radial flow of the gas stream; and a second baffle disposed on the inner surface of the second end cap and arranged to direct radial flow of the gas stream.

Preferably, in the case of including the centrifugal fan, the centrifugal fan is arranged to rotate with the first end cap or the second end cap or by a separate motor.

Preferably, in the case of including a plurality of said first baffles, said first baffles have a continuous curved shape or comprise a plurality of segments arranged intermittently along the same or different curved paths.

Preferably, in the case of including a plurality of said second baffles, said second baffles have a continuous curved shape or comprise a plurality of segments arranged intermittently along the same or different curved paths.

Preferably, the centrifugal fan is disposed on one of the first end cover and the second end cover and is further provided with a plurality of the first baffles or a plurality of the second baffles In the case where the centrifugal fan is located in the radial direction of the plurality of the first baffles or the plurality of the second baffles a side, and the centrifugal fan and the plurality of the first baffles or the plurality of the second baffles are arranged to direct the airflow to flow in the same direction, that is, both direct the airflow to flow or both to direct the airflow Heart flow.

Preferably, in the case where the air flow driving mechanism is disposed on the inner surfaces of the first end cover and the second end cover, one of the first end cover and the second end cover is located The airflow drive mechanism on the upper portion is arranged to direct the airflow to flow, and the airflow drive mechanism on the other of the first end cap and the second end cap is arranged to direct the airflow to the centripetal flow.

Preferably, a plurality of longitudinal passages are formed on the yoke portion radially inward of the winding teeth.

Preferably, a heat dissipating device is disposed on an outer surface of the first end cap and/or an outer surface of the second end cap.

Preferably, the outer rotor type motor is an in-wheel motor, and further includes a hub disposed radially outward of the rotor and rotating with the rotor.

According to the present invention, by causing the airflow to circulate in the internal space of the motor, the airflow heated by the heat generated by the windings is sufficiently exchanged with the first end cap and the second end cap, and the heat is passed through the first end cap and the second end. The end cap is dissipated into the external environment so that the thermal resistance between the winding and the external environment can be significantly reduced, thereby significantly improving the heat dissipation effect of the outer rotor type motor.

DRAWINGS

1 is a schematic perspective view of a hub motor in accordance with a preferred embodiment of the present invention;

2 is an exploded view of a hub motor in accordance with a preferred embodiment of the present invention;

Figure 3 is another exploded view of a hub motor in accordance with a preferred embodiment of the present invention;

Figure 4 is a schematic cross-sectional perspective view of the hub motor in the axial direction in accordance with a preferred embodiment of the present invention;

Figure 5 is a side elevational view of the hub motor with the end cap removed, in accordance with a preferred embodiment of the present invention;

Figure 6 is a front elevational view of a first end cap in accordance with a preferred embodiment of the present invention;

Figure 7 is a front elevational view of a second end cap in accordance with a preferred embodiment of the present invention;

Figure 8 is a cross-sectional view of the hub motor in the axial direction in accordance with a preferred embodiment of the present invention, wherein the arrows show the direction of flow of the air.

detailed description

Preferred embodiments of the present invention are described in detail below with reference to examples. It should be understood by those skilled in the art that these exemplary embodiments are not intended to limit the invention.

1 is a schematic perspective view of a hub motor in accordance with a preferred embodiment of the present invention, FIG. 2 is an exploded view of a hub motor in accordance with a preferred embodiment of the present invention, and FIG. 3 is another exploded view of the hub motor in accordance with a preferred embodiment of the present invention, 4 is a schematic cross-sectional perspective view of the hub motor in an axial direction in accordance with a preferred embodiment of the present invention, and FIG. 5 is a side elevational view of the hub motor with the end cap removed, in accordance with a preferred embodiment of the present invention. As shown in FIGS. 1-5, an in-wheel motor 1 according to a preferred embodiment of the present invention includes a shaft 10, a stator 20 that surrounds the shaft 10 and is fixedly disposed on the shaft 10, and a rotor that is disposed radially outward of the stator 20 around the shaft 10. 30. A first end cap 40 located axially to the left of the stator 20 and fixedly coupled to the rotor 30, and a second end cap 50 located axially to the right of the stator 20 and fixedly coupled to the rotor 30. There is a gap between the inner surface of the first end cap 40 and the stator 20 and between the inner surface of the second end cap 50 and the stator 20. Both ends of the shaft 10 can be supported on, for example, a frame (not shown). The first end cap 40 and the second end cap 50 are rotatably supported on the shaft 10 by first and second bearings 11 and 12, respectively, provided on the shaft 10 on both sides of the stator 20. The first end cap 40 and the second end cap 50 together with at least a portion of the rotor 30 define an interior space of the hub motor 1 in which the stator 20 is located. Thus, after the motor is energized, the rotor 30 and the first end cap 40 and the second end cap 50, which are fixedly coupled to the rotor 30, are rotatable about the stator 20 and the shaft 10. The hub motor 1 also typically includes a hub 60 that is radially outward of the rotor 30 and that rotates with the rotor. Although the hub 60 is shown as being integrally formed with the rotor 30 in the figures, the hub 60 may be formed separately from the rotor 30 and fixedly coupled together by welding or a close fit or the like.

In the present application, "first" and "second" in "first end cap" and "second end cap" are used for convenience of description only, and do not constitute a special limitation of the end cap itself. For example, the first end cap may also be an end cap located on the axially right side of the stator, and at this time, the second end cap may be in position. The end caps on the axial left side of the stator, that is, the positions of the first end cap and the second end cap are interchangeable.

Figure 6 is a front elevational view of a first end cap and a front view of a second end cap in accordance with a preferred embodiment of the present invention. As shown in FIGS. 2-4 and 6-7, the inner surface of the first end cover 40 may be provided with a first baffle 41 protruding toward the inner space, and the inner surface of the second end cover 50 may be provided with a direction. The second baffle 51 is protruded from the inner space. Although a baffle is provided on the inner surfaces of the first end cap 40 and the second end cap 50 in the preferred embodiment, it should be understood that only the inner surface of the first end cap 40 or the second end cap 50 may be provided. Set the baffle on it. The specific structure and function of the first baffle and the second baffle will be described in detail later. Heat sinks such as

heat dissipating ribs

43 and 53 may also be disposed on the outer surfaces of the first end cap 40 and the second end cap 50 such that the first end cap and the second end cap may be more fully heated to the external environment. exchange. The heat dissipating device may be a heat dissipating rib, or may be any other structure, component or device that can achieve the aforementioned heat exchange purpose, such as different forms of fins. The first end cap 40 and the second end cap 50, as well as the baffles and heat sinks thereon, are preferably made of a material that facilitates heat dissipation.

4 and 5, the stator 20 located radially inward of the rotor 30 includes a yoke portion 21 formed by stacking a plurality of stator core pieces together and located radially inward of the yoke portion 21 and for fixing the yoke portion 21 fixedly A support portion 23 supported on the shaft 10. The yoke portion 21 is formed with a plurality of winding teeth 211 radially outward, and a winding 213 is wound around each of the winding teeth 211. The yoke portion 21 is formed with a plurality of longitudinal passages 215 on the radially inner side of the winding teeth 211. Preferably, the plurality of longitudinal channels 215 are evenly distributed along the circumferential direction. Since a plurality of longitudinal passages 215 are provided, the heat exchange area with the airflow flowing longitudinally through the stator can be significantly increased, and since the longitudinal passages 215 are disposed adjacent to the windings 213, heat can be quickly and efficiently transferred from the windings 213 away from the windings. The support portion 23 is disk-shaped, and it can be fixedly coupled to the yoke portion 21 by a connection such as welding or a close fitting. The support portion 23 may be hollowed out to form a plurality of openings 233 between adjacent spokes 231. Preferably, the plurality of openings 233 are also uniformly distributed along the circumferential direction. The support portion 23 having the spokes 231 can not only reliably support the yoke portion 21 but also allow the airflow to smoothly pass. It should be understood that the plurality of openings 233 may also be a plurality of circular or other shaped apertures formed in the support portion 23.

As shown in FIGS. 2, 4, and 6, the centrifugal fan 45 may also be disposed on the inner surface of the first end cap 40. The primary function of the centrifugal fan is to rapidly circulate airflow within the motor through the plurality of longitudinal passages 215 and the plurality of openings 233, whereby the airflow can carry heat away from the windings 213 and through the The first baffle and/or the second baffle heat exchange, and finally the heat is dissipated to the external environment through the first end cover 40 and/or the second end cover 50 to achieve cooling of the hub motor. The centrifugal fan 45 may be arranged to rotate with the first end cap 40, or the centrifugal fan 45 may be driven by a separate motor (not shown). When the centrifugal fan 45 is driven by a separate motor, the rotational speed of the motor can be changed according to the real-time demand of the cooling hub motor, so that the rotational speed of the centrifugal fan 45 and the circulating flow velocity of the airflow can be changed in real time, thereby better satisfying the hub motor Heat dissipation requirements in different situations.

As shown in Figures 2, 4 and 6, the centrifugal fan 45 is preferably disposed at the center of the inner surface of the first end cap 40. At least one first baffle 41 may be formed on the inner surface of the first end cap 40. Preferably, the first end cap 40 has a plurality of first baffles 41 on its inner surface, and they are arranged to be capable of directing airflow centrifugation, i.e., radially outward. Preferably, the centrifugal fan 45 is disposed radially inward of the plurality of first baffles 41. For example, the first baffle 41 may have a continuous curved shape. As shown in FIG. 6, the bending direction of the curved shape is substantially opposite to the rotation direction of the first end cover 40 when the hub motor is in operation, that is, when the first end cover 40 is rotated in the direction of the arrow A shown in FIG. The direction in which a baffle 41 extends from the radially inner side toward the radially outer side is substantially opposite to the arrow direction A shown. Thereby, it is advantageous to cause the airflow to flow radially and efficiently along the first deflector 41 in a rapid and effective manner, and the noise is small. The plurality of first baffles 41 may be evenly spaced along the circumferential direction of the inner surface of the first end cap 40, or may be unevenly distributed. In addition, the first baffle 41 may not be continuous, but includes a plurality of segments arranged intermittently along the same or different curved paths, which may also serve to guide the airflow to flow radially outward, but it is possible The complexity of the processing is reduced, the amount of baffle material is reduced, and the overall weight of the first end cap 40 is reduced. The first baffle 41 can be disposed on the inner surface of the first end cap 40 in various manners, such as integrally formed or welded, bonded, or the like.

As shown in FIG. 7, at least one second baffle may be formed on the inner surface of the second end cover 50. 51. Preferably, the second end cap 50 has a plurality of second baffles 51 on its inner surface, and they are arranged to direct the flow of gas to the center of the heart, i.e., radially inward. In the radial direction of the inner surface of the second end cap 50, a plurality of second baffles 51 may be disposed in a region corresponding to the plurality of first baffles 41 on the first end cap 40. Similar to the first baffle, the second baffle may also have a continuous curved shape or include a plurality of segments that are intermittently arranged along the same or different curved paths, as long as it can guide the gas radial The purpose of flowing inward is enough. The second baffle 51 may be disposed on the inner surface of the second end cap 50 in the same or different manner as the first baffle 41.

Figure 8 is a cross-sectional view of the hub motor in the axial direction in accordance with a preferred embodiment of the present invention, wherein the arrows show the direction of flow of the air. First, the centrifugal fan 45 causes the airflow to flow radially outward from the center of the inner surface of the first end cap 40, and then the airflow continues to flow radially outward under the action of the plurality of first baffles 41, flowing through the airflow. After the plurality of longitudinal passages 215, the plurality of second baffles 51 on the second end cap 50 cause the airflow to flow radially inward, and then the airflow flows through the plurality of openings 233 formed in the support portion 23, and finally in the centrifugal fan. Start the next cycle with the effect of 45. In each cycle, as the airflow flows through the longitudinal passage 215, the heat generated by the winding 213 is transferred to the flowing airflow, and then, as the heated airflow flows through the first end cap 40 and the first baffle 41, When the second end cover 50 and the second baffle 51 are in contact, the heated air flow exchanges heat with the first end cover 40 and the first baffle 41 and the second end cover 50 and the second baffle 51, and the heat is Passing to the first end cap 40 and the first baffle 41 and the second end cap 50 and the second baffle 51, so that the airflow is cooled while heat is further transferred to the first end cap 40 and the second end cap 50. Finally, the first end cover 40 and the second end cover 50 and the heat dissipating device disposed thereon are transmitted to the external environment, thereby achieving the purpose of cooling the hub motor. The plurality of baffles 41 on the first end cover 40 not only serve the purpose of heat transfer, but also function as a centrifugal fan by its shape and arrangement, thereby facilitating further guiding the airflow to flow radially outward. Similarly, the plurality of baffles 51 on the second end cap 50 may also be arranged to direct the flow of gas radially inward while heat transfer.

In the foregoing preferred embodiment, the centrifugal motor 45 on the inner surface of the first end cap 40, the first baffle 41 on the inner surface of the first end cap 40, and the second baffle on the inner surface of the second end cap 50 51 can be used as an air flow driving mechanism for urging airflow through a plurality of longitudinal passages and a plurality of openings Circulating flow in the internal space of the motor. It should be understood that the foregoing airflow driving purpose can be achieved by any of the above three. For example, when only the centrifugal fan 45 on the inner surface of the first end cap 40 is employed, the air flow can still be transported radially outward and through the inner surface of the first end cap 40, thereby being passed through the plurality of longitudinal channels Heating, then flowing through the inner surface of the second end cap and the plurality of openings, and finally returning to the centrifugal fan. During this process, the heated gas stream can be directly exchanged with the first end cap and the second end cap for cooling purposes. Similarly, when the first baffle 41 on the inner surface of the first end cover 40 or the second baffle 51 on the inner surface of the second end cover 50 is used, the air flow can also flow along a predetermined closed path, thereby To achieve the purpose of cooling. In the case where a plurality of first baffles 41 and a plurality of second baffles 51 are employed, one of the plurality of first baffles 41 and the plurality of second baffles 51 is set to cause The airflow is centrifugally flowed, and the other is arranged to cause the airflow to flow toward the center of the heart, but in the case where only the plurality of first baffles 41 or the plurality of second baffles 51 are employed, the plurality of first baffles 41 The plurality of second baffles 51 may all be arranged to cause the airflow to flow centrifugally, or both may be arranged to cause the airflow to flow centripetally. Further, in addition to the above three, any other air flow driving mechanism capable of achieving the same or similar purposes may be employed. Further, the flow path of the air flow is not limited to the arrow shown in Fig. 8, but may be a flow path opposite thereto, which can be realized by changing the installation position and arrangement form of the air flow driving mechanism.

According to the present invention, the air flow heated by the windings is exchanged with the first end cover and the second end cover by causing the air flow to rapidly circulate through the plurality of longitudinal passages on the stator yoke and the plurality of openings on the support portion. Heat, and thus heat, is dissipated into the external environment through the first end cap and the second end cap, so that the thermal resistance between the winding and the external environment can be significantly reduced, thereby significantly improving the heat dissipation effect of the hub motor.

The invention has been described in detail above with reference to the specific embodiments. It is apparent that the above description and the embodiments shown in the drawings are intended to be illustrative and not restrictive. For example, in the preferred embodiment a plurality of longitudinal passages are formed in the portion of the stator yoke adjacent the winding, it being understood that even if a longitudinal passage is not formed, the flow of air flows through the gap around the winding, only this and formation Longitudinal channels reduce the heat dissipation of the motor. Another In addition, although the outer rotor type motor is described as a hub motor in the preferred embodiment, it should be understood that the present invention is also applicable to other outer rotor type motors such as fan motors. It is apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

An outer rotor type motor comprising:

Axis (10);

a stator (20) fixedly disposed on the shaft (10) around the shaft (10), wherein the stator (20) includes a yoke (21) formed by stacking a plurality of stator core pieces together And a support portion (23) located radially inward of the yoke portion (21) for fixedly supporting the yoke portion (21) on the shaft (10), the yoke portion (21) being radially a plurality of winding teeth (211) are formed outwardly, a winding (213) is wound around each of the winding teeth (211), and a plurality of openings (233) are formed on the supporting portion (23);

a rotor (30) disposed radially outward of the stator (20) about the shaft (10);

a first end cap (40) rotatably supported on the shaft (10) by a first bearing (11) and fixedly coupled to the rotor (30);

a second end cap (50) rotatably supported on the shaft (10) by a second bearing (13) and fixedly coupled to the rotor (30), the first end cap (40) and The second end cap (50) together with at least a portion of the rotor (30) defines an interior space of the outer rotor type motor;

An air flow drive mechanism for urging airflow through a gap around the winding (213) and circulating the plurality of openings (233) in the interior space.
The outer rotor type motor according to claim 1, wherein said air flow driving mechanism is at least one of the following:

a centrifugal fan (45) on an inner surface of one of the first end cap (40) and the second end cap (50);

a first baffle (41) disposed on an inner surface of the first end cap (40) and arranged to direct radial flow of the gas flow;

A second baffle (51) disposed on an inner surface of the second end cap (50) and arranged to direct radial flow of the gas flow.
The outer rotor type motor according to claim 2, wherein, in the case of including the centrifugal fan (45), the centrifugal fan is disposed along with the first end cover (40) or the first The two end caps (50) rotate together or are driven by separate motors.
The outer rotor type motor according to claim 2, wherein, in the case of including a plurality of said first baffles (41), said first baffles have a continuous curved shape or include discontinuities Multiple segments arranged along the same or different curved paths.
The outer rotor type motor according to claim 2, wherein in the case of including a plurality of said second baffles (51), said second baffles have a continuous curved shape or include discontinuities Multiple segments arranged along the same or different curved paths.
The outer rotor type motor according to claim 2, wherein said centrifugal fan (45) is disposed on one of said first end cover (40) and said second end cover (50) and In the case where a plurality of the first baffles (41) or a plurality of the second baffles (51) are further provided, the centrifugal fan is located in a plurality of the first baffles (41) or a plurality of the second baffles (51) radially inward, and the centrifugal fan (45) and the plurality of the first baffles (41) or the plurality of the second baffles (51) Both are arranged to direct the flow of gas in the same direction, i.e., both direct the flow of the air to flow or both to direct the flow of the gas to the heart.
The outer rotor type motor according to claim 2, wherein said air flow driving mechanism is provided on an inner surface of said first end cover (40) and said second end cover (50) Lower, the airflow drive mechanism located on one of the first end cap (40) and the second end cap (50) is arranged to direct airflow of the airflow while located at the first end cap (40) And the airflow drive mechanism on the other of the second end caps (50) is arranged to direct the flow of airflow to the center of the heart.
The outer rotor type motor according to claim 1, wherein a plurality of longitudinal passages (215) are formed in said yoke portion (21) radially inward of said winding teeth (211).
The outer rotor type motor according to any one of claims 1 to 8, characterized in that the outer surface of the first end cover (40) and/or the outer surface of the second end cover (50) A heat sink is provided.
The outer rotor type motor according to any one of claims 1 to 8, wherein the outer rotor type motor is an in-wheel motor, and further comprising a radially outer side of the rotor (30) and A rotor (60) in which the rotor rotates.