CN217984779U

CN217984779U - External rotor motor

Info

Publication number: CN217984779U
Application number: CN202221931563.9U
Authority: CN
Inventors: 冯晓灿; 鲍康龙
Original assignee: Sijieda Technology Suzhou Co ltd
Current assignee: Suzhou Deli Technology Co ltd
Priority date: 2022-07-26
Filing date: 2022-07-26
Publication date: 2022-12-06
Anticipated expiration: 2032-07-26

Abstract

The utility model discloses an external rotor electric machine, include: the impeller comprises a plurality of blades which are arranged at intervals in the circumferential direction; the rotor shell is coaxially arranged with the blades and is relatively fixed, and the rotor shell and the blades synchronously rotate; the rotor housing has an outer surface; at least one of the blades includes a main portion located radially inward of the outer surface and an extension located radially outward of the outer surface. The utility model discloses an external rotor electric machine has better radiating effect.

Description

External rotor motor

Technical Field

The utility model belongs to the technical field of electric tool, concretely relates to an external rotor electric machine for electric tool.

Background

The motor is used as a power source, a large amount of heat can be generated in the operation process, and if the heat is lost in time, the service life of motor parts can be reduced, and even operation faults can be caused. Therefore, how to improve the heat dissipation effect of the motor is an important issue to be considered in the design of the motor.

The existing heat dissipation structure of an outer rotor motor is generally provided with synchronously rotating impellers, and in the motor operation process, the impellers rotate together with a rotor to generate heat dissipation airflow. Generally, the impeller is arranged side by side with the rotor, and the blades of the impeller are closely adjacent to but not overlapped with the rotor housing in the axial direction, and the rotor rotates to drive the impeller to rotate, so that the heat dissipation airflow is generated. The heat dissipation effect of this heat dissipation method still needs to be improved.

Accordingly, there is a need for improvements in the art that overcome the deficiencies in the prior art.

SUMMERY OF THE UTILITY MODEL

Therefore, the utility model aims to solve the technical problem of poor heat dissipation of the outer rotor motor in the prior art.

In order to solve the technical problem, the utility model provides an external rotor electric machine, include:

the impeller comprises a plurality of blades which are arranged at intervals in the circumferential direction;

the rotor shell is coaxially arranged with the impeller and is relatively fixed, and the rotor shell and the blades synchronously rotate; the rotor housing has an outer surface;

at least one of the blades includes a main body portion located radially inward of the outer surface, and an extension portion located radially outward of the outer surface.

In one embodiment, the main body portion is plate-shaped, and the main body portion extends radially.

In one embodiment, the main body portion and the extension portion are coplanar, and the blade is generally L-shaped.

In one embodiment, the extension portion extends axially from a radial end of the main body portion in a direction toward the rotor housing.

In one embodiment, the extension comprises a first portion and a second portion connected, the axial extension of the first portion being outside the rotor housing and the axial extension of the second portion being inside the axial extension of the rotor housing.

In one embodiment, the second portion is spaced from the outer surface; alternatively, the second portion abuts the outer surface.

In one embodiment, the impeller further includes a baffle in an annular structure, the end of the extension is fixedly connected with or integrally formed with the baffle, and the baffle includes a baffle surface facing one side of the extension.

In one embodiment, the outer rotor motor further includes a connection frame for fixedly connecting the impeller with the rotor housing, the connection frame includes a ring portion, an outer surface of the ring portion is in interference connection with an inner surface of the rotor housing, the connection frame is fixedly connected with the blades or integrally formed with the blades, and the blades are in heat conduction connection with the rotor housing through the connection frame.

In one embodiment, the outer rotor motor further includes a plurality of magnetic steels fixedly disposed in the rotor housing, the connection frame further includes a plurality of positioning portions fixedly disposed with the ring portion, and a length direction of each positioning portion is parallel to an axial direction of the rotor housing and extends into a space between two adjacent magnetic steels to position the magnetic steels.

In one embodiment, the connecting frame and/or the blade is of an aluminum structure.

The technical scheme provided by the utility model, following advantage has:

the utility model provides an external rotor electric machine, at least one blade of impeller all include main part and extension, and the main part is located the radial inboard of surface, and the extension is located the radial outside of surface, extension have increased the area of the drive air of blade, have improved the amount of wind, can locate the drive heat dissipation air current at rotor case's surface, help improving the radiating efficiency of rotor.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic perspective view of an external rotor motor according to an embodiment of the present invention;

fig. 2 is a partially exploded view of the outer rotor motor shown in fig. 1;

fig. 3 is a schematic cross-sectional structure view of the external rotor motor shown in fig. 1;

fig. 4 is a schematic perspective view of an external rotor electric machine according to another embodiment of the present invention;

fig. 5 is a perspective view illustrating an impeller of the outer rotor motor shown in fig. 4.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments. It should be noted that, in the case of no conflict, the embodiments and features of the embodiments of the present invention may be combined with each other.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

In the present application, where the contrary is not intended, the use of directional words such as "upper, lower, top and bottom" is generally with respect to the orientation shown in the drawings, or with respect to the component itself in the vertical, perpendicular or gravitational direction; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

Example 1

The embodiment provides an outer rotor motor. Referring to fig. 1 to 3, the external rotor motor includes a rotating shaft 10, a rotor housing 30, magnetic steel 40, a stator 50, and an impeller 20.

The shaft 10 has an axis of rotation, and the axes of the rotor housing 30, the stator 50 and the impeller 20 are all collinear with the axis of rotation of the shaft 10. The rotor case 30 is in a sleeve shape, both ends of which are penetrated, and the stator 50 is disposed in the rotor case 30. The number of the magnetic steels 40 is multiple, the magnetic steels are fixedly arranged on the inner surface of the rotor shell 30, the magnetic steels surround the circumferential direction of the stator 50, and gaps between the adjacent magnetic steels 40 are basically the same. A gap is formed between the stator 50 and the magnetic steel 40, a stator coil (not shown) is wound on the stator 50, when the stator coil is energized, an electromagnetic field is generated, and the magnetic steel 40 rotates around the rotation axis under the action of the magnetic field, so that the rotor shell 30 is driven to rotate synchronously.

Referring to fig. 2, the impeller 20 includes a plurality of circumferentially spaced blades 23. The rotor housing 30 and the impeller 20 are coaxially arranged and relatively fixed, and the rotor housing 30 and the blades 23 rotate synchronously, so that the blades 23 are driven to drive air to generate heat dissipation airflow. Specifically, the rotor housing 30 has an outer surface 32, and the impeller 20 is fixedly coupled to the rotor housing 30 such that the impeller 20 rotates synchronously when the rotor housing 30 rotates. During the rotation of the impeller 20, a driving airflow is generated, and the airflow flowing through the rotor housing 30 and the stator 50 located in the rotor housing 30 can reduce the heat of the corresponding components, thereby avoiding abnormal operation of the external rotor motor caused by over-high temperature.

Specifically, the impeller 20 includes a hub 21, and a plurality of blades 23 are uniformly spaced on the hub 21. The hub 21 is sleeved on the rotating shaft 10. The number of the blades 23 is plural, and the plural blades 23 are provided at intervals in the circumferential direction of the hub 21. The blades 23 may be fixedly provided to the hub 21 or may be integrally formed. More specifically, the hub 21 is fixedly disposed on the rotating shaft 10, and the rotor housing 30 drives the rotating shaft 10 to rotate synchronously by driving the impeller 20.

At least one blade 23 includes a main body portion 231 and an extension portion 232. The main body 231 is located radially inward of the outer surface 32 of the rotor case 30, and the extension 232 is located radially outward of the outer surface 32. According to the outer rotor motor provided by the embodiment, the extension part increases the area of the driving air of the blade, the air quantity of the impeller is improved, the integral heat dissipation effect of the motor is improved, and the stable operation and the longer service life of the outer rotor motor are guaranteed.

In a particular embodiment, body portion 231 extends radially and includes an inner end fixedly disposed with hub 21 and an outer end opposite the inner end. The extension 232 extends axially, and in particular, the extension 232 extends axially from the radially outer end of the main body 231 in a direction toward the rotor housing 30. The rotor case 30 is arranged in order with the main body 231 in the axial direction of the rotary shaft 10. The inner end and the outer end of the main body 23 are both relative to the rotation axis of the impeller, and the end close to the rotation axis is the inner end, and the end far away from the rotation axis is the outer end.

Referring to fig. 2 and 3, the extension 232 includes a first portion 2321 and a second portion 2322 connected to each other, the first portion 2321 extends axially outside the rotor housing 30, and the second portion 2322 extends axially inside the rotor housing 30. Specifically, radially, the first portion 2321 is located radially outward of the outer surface 32 of the rotor housing 30; in the axial direction, the first portion 2321 is disposed adjacent to the rotor housing 30 and outside the rotor housing 30. Radially, the second portion 2322 is located radially outward of the outer surface 32 of the rotor housing 30; in the axial direction, the second portion 2322 extends from the first portion 2321 toward the outer surface 32 of the rotor housing 30 to a predetermined distance from the outer surface 32 of the rotor housing 30. Preferably, the first and

second portions

2321 and 2322 are integrally formed.

As described above, the first portion 2321 radially extends beyond the main body 231, so that the air volume of the impeller 20 is increased, and the overall heat dissipation effect of the motor is improved. In this embodiment, the second portion 2322 extends axially for a certain length on the basis of the first portion 2321, so as to further improve the air volume of the impeller and improve the overall heat dissipation effect of the motor.

To facilitate manufacturing assembly, in one embodiment, the second portion 2322 of the extension 232 is disposed in a spaced relation to the outer surface 32 of the rotor housing 30. Specifically, the distance between the second portion 2322 of the plurality of extensions 232 and the outer surface 32 of the rotor housing 30 is uniform. The inner edge of the second portion 2322 of the extension 232, viewed axially, defines a generally circular profile centered approximately on the axis of the shaft 10 and having a radius slightly larger than the outer diameter of the rotor housing 30.

In other embodiments, the second portion 2322 abuts the outer surface 32 of the rotor housing 30, i.e., the second portion 2322 abuts the outer surface 32 of the rotor housing 30 without a gap therebetween. Thus, the air flow is prevented from flowing through the gap between the second part 2322 and the outer surface 32 of the rotor housing 30, the efficiency of the driving air flow of the second part 2322 is improved, and the heat dissipation effect is further guaranteed.

The extension lengths and directions of the extensions 232 of the plurality of blades 23 are the same, and the extensions 232 of the plurality of blades 23 are uniformly spaced along the circumferential direction. When the impeller 20 rotates, the main body 231 and the extension 232 drive air to generate an air flow. Since the extension 232 expands the surface area of the driving air of the vane 23, the air volume of the impeller 20 is increased. Since the second portion 2322 of the extension 232 axially extends on the outer surface 32 of the rotor casing 30, the airflow speed and the flow rate of the outer surface 32 of the rotor casing 30 can be increased, and the heat dissipation effect of the rotor casing 30 can be improved.

In some embodiments, the main body portion 231 extends in a radial direction of the impeller 20, and the length of the extension portion 232 extends in a direction parallel to the axis of rotation of the impeller 20. Specifically, the blade 23 is sheet-shaped as a whole, the main body 231 and the extension 232 are coplanar, and the blade 23 is L-shaped as a whole. The extension 232 and the body 231 are integrally formed. The blades 23 extend outward in the radial direction of the hub 21, and the blades 23 are divergent outward in the radial direction of the hub 21 as viewed from the axial direction of the impeller 20. The length direction of the extension 232 is parallel to the rotation axis of the rotation shaft 10. The blades 20 are arranged in such a way, the surface of the blades can be enabled to act on air vertically in the rotating process of the blades, and large airflow is generated, so that the heat dissipation efficiency is guaranteed by utilizing the airflow.

The plurality of extensions 232 are circumferentially spaced radially outward of the rotor housing and drive air during rotation to generate a heat dissipating airflow in order to ensure a sufficient amount of heat dissipating airflow. Preferably, the length of the second portion 2322 at the outer surface 32 of the rotor housing 30 accounts for at least 1/3 of the total axial length of the rotor housing 30. That is, the ratio of the length of the second portion 2322 located above the outer surface 32 of the rotor case 30 to the total axial length of the rotor case 30, as viewed in the axial direction, is not less than 1/3. In this embodiment, the length of the extension 232 is parallel to the axial direction of the rotor housing 30, and the length of the second part 2322 of the extension 232 located on the outer surface 32 of the rotor housing 30 is 1/2 of the total length of the rotor housing 30.

Further, the impeller 20 is a heat-conducting structural member, and the impeller 20 is connected with the rotor casing 30 in a heat-conducting manner. In this embodiment, the impeller 20 is connected to the rotor housing 30 in a contact manner, and the contact portion realizes heat conduction between the impeller 20 and the rotor housing 30. Since the extension 232 increases the surface area of the blade 23, the heat dissipation area thereof is increased, thereby accelerating the heat dissipation of the rotor case 30.

In some embodiments, the external rotor motor further includes a connection frame 25 for fixedly connecting the impeller 20 with the rotor housing 30, the connection frame 25 may be fixedly connected with the blades 23, or may be integrally formed, the blades 23 are thermally connected with the rotor housing 30 through the connection frame 25, and heat of the rotor housing 30 is transferred to the surface of the blades 23 through the connection frame 25 and dissipated through the blades 23.

With continued reference to fig. 2 and 3, the connecting frame 25 includes a ring portion 251, an outer surface of the ring portion 251 is in interference fit with an inner surface of the rotor housing 30, and specifically, the ring portion 251 is a cylindrical ring, is smaller than the rotor housing 30 in size, and is tightly fitted with the inner surface of the rotor housing 30, so as to achieve contact heat conduction.

The connecting frame 25 further includes a positioning portion 252, the positioning portion 252 is long and extends along an axial direction parallel to the rotating shaft 10, one end of the positioning portion 252 is connected to the annular end surface of the ring portion 251, and the other end extends into between two adjacent magnetic steels 40 to position the magnetic steels 40. Specifically, the other end of the positioning portion 252 extends beyond the magnetic steel 40, but not beyond the rotor case 30. The positioning portion 252 is disposed between adjacent magnetic steels 40 in a penetrating manner, and is used for positioning the magnetic steels 40 to prevent the magnetic steels 40 from loosening and falling off.

The connection frame 25 is fixedly connected to the rotor case 30 through the ring portion 251, and conducts a large amount of heat between the ring portion 251 and the rotor case 30. To facilitate heat conduction and to accelerate heat dissipation from the rotor housing 30, the connection frame 25 is integrally formed with the blade 23. The connecting frame 25 and the blades 23 are made of aluminum which is easy to transfer heat, so that the heat dissipation efficiency is higher.

The outer rotor motor further includes a positioning frame 60 for positioning the stator 50. Referring to fig. 2 and 3, the positioning frame 60 includes a shaft portion 61 and a bracket 62, the shaft portion 61 has a shaft hole for passing through the rotating shaft 10, the shaft hole has a size larger than a diameter of the rotating shaft 10, the rotating shaft 10 is in clearance fit with the shaft portion 61, and an outer surface of the shaft portion 61 is fixedly connected with the stator 50, thereby supporting the stator 50. The support 62 includes a plurality of, connects on axial region 61, and support 62 all radially extends to arrange, and its end sets up the locating hole for be connected with location structure, thereby realize supporting the location. Preferably, the number of the brackets 62 is 3, and the brackets are arranged at regular intervals along the circumferential direction of the shaft portion 61. The spacer 60 is a one-piece fabricated part.

In order to improve the heat dissipation effect, the connecting frame 25 or the blades 23 are made of aluminum. Preferably, the connecting frame 25 and the blades 23 are both made of aluminum, and since aluminum has good thermal conductivity, heat transfer with the rotor housing 30 can be accelerated, and the heat dissipation effect of the rotor housing is improved by the increased heat dissipation surface area.

The axial directions of the rotor housing 30 and the impeller 20 are both relative to the rotation axis thereof, and the axial directions of the rotor housing 30 and the impeller 20 are both extension directions of the rotation axis. The radial direction of the impeller 20 is the radial direction of the hub.

In summary, the outer rotor motor provided by the embodiment has the following beneficial effects: the blades of the impeller are provided with the extension parts, so that the action area of driving airflow of the blades can be increased, and the air quantity of the impeller is improved, thereby improving the airflow heat dissipation effect; meanwhile, the additionally arranged extension part also increases the heat dissipation area of the blade and improves the heat dissipation efficiency of the blade; the extension part at least partially extends to the circumferential surface of the rotor shell, and drives the circumferential surface of the rotor shell to form heat dissipation airflow, so that the heat dissipation effect of the outer surface of the rotor shell is improved; the impeller is made of aluminum with good heat conduction, and the heat dissipation effect is further guaranteed.

Example 2

The utility model also provides an external rotor electric machine. Referring to fig. 4 and 5, the structure of the outer rotor motor provided in this embodiment is similar to that of the outer rotor motor provided in embodiment 1, and the difference is only the structure of the impeller, and only the difference structure is described in detail below, and for the purpose of brevity of description, the same components are denoted by the same reference numerals and are not described again.

The outer rotor motor provided by the embodiment includes a rotating shaft 10, a rotor housing 30, an impeller 120, a stator 50, magnetic steel 40, and a positioning frame 60. The impeller 120 includes a hub 121, blades 123, and a positioning frame 125, wherein the blades 123 include a main body 1231 and an extending part 1232. The structure of the impeller 120 is the same as that of embodiment 1, and it can be seen from each other, except that the impeller 120 further includes a baffle 124 disposed at the end of the extension 1232.

Referring to fig. 5, in particular, the flow guiding plate 124 is substantially annular, and includes a flow guiding surface 1240 facing one side of the extensions 1232, and the end of each extension 1232 is fixedly connected to the flow guiding surface 1240. The arrangement of the flow guide plate 124 can suppress the formation of negative pressure on the outer surface of the rotor housing 30, thereby suppressing the difference between the external pressure and the internal pressure of the rotor housing 30, reducing the air volume of the air flow in the rotor housing 30 flowing out to the outside of the rotor housing under the action of the negative pressure, ensuring the air flow rate in the rotor housing 30, and ensuring the heat dissipation effect of the internal components. On the other hand, the guide plate 124 further increases the heat dissipation area of the impeller 120, so that the heat conduction efficiency is increased, and the heat dissipation effect of the motor is guaranteed.

In one embodiment, flow guide surface 1240 of flow guide plate 124 is substantially perpendicular to the axial direction of rotor housing 30, and extensions 1232 are each parallel to the axis of rotation of shaft 10. The air deflector 124, the extension part 1232 and the main body part 1231 are both made of aluminum, so that the heat conduction efficiency is further guaranteed. The guide surfaces 1240 may have other angles, such as an angle less than 90 degrees with the axial direction of the rotor housing 30, such as angles of 80 degrees, 60 degrees, etc., and are not listed.

It is obvious that the above described embodiments are only some of the embodiments of the present invention, and not all of them. Based on the embodiment of the utility model, ordinary technical personnel in this field can make other different forms of change or change under the prerequisite of not making creative work, all should belong to the scope of protection of the utility model.

Claims

1. An external rotor electric machine, comprising:

2. The external rotor electric machine of claim 1, wherein the body portion is plate-shaped, the body portion extending radially.

3. The external rotor electric machine as claimed in claim 1, wherein the main body portion and the extension portion are coplanar, and the blade is L-shaped as a whole.

4. The external rotor electric machine of claim 1, wherein the extension extends axially from a radial end of the main body portion in a direction toward the rotor housing.

5. The external rotor electric machine of claim 4, wherein the extension includes a first portion and a second portion connected, the axial extent of the first portion being outside the rotor housing and the axial extent of the second portion being within the axial extent of the rotor housing.

6. The external rotor electric machine of claim 5, wherein the second portion is spaced from the outer surface; alternatively, the second portion abuts the outer surface.

7. The external rotor electric machine of any one of claims 1-6, wherein the impeller further comprises a baffle plate in an annular structure, the end of the extension is fixedly connected or integrally formed with the baffle plate, and the baffle plate comprises a baffle surface facing one side of the extension.

8. The external rotor electric machine of claim 1, further comprising a connection frame for fixedly connecting the impeller with the rotor housing, wherein the connection frame comprises a ring portion, an outer surface of the ring portion is in interference connection with an inner surface of the rotor housing, the connection frame is fixedly connected or integrally formed with the blades, and the blades are in heat conduction connection with the rotor housing through the connection frame.

9. The external rotor electric machine of claim 8, wherein the external rotor electric machine further comprises a plurality of magnetic steels fixedly disposed in the rotor housing, and the connection frame further comprises a plurality of positioning portions fixedly disposed with the ring portion, and a length direction of each positioning portion is parallel to an axial direction of the rotor housing and extends into between two adjacent magnetic steels to position the magnetic steels.

10. The external rotor electric machine of claim 8, wherein the connection frame and/or the blades are of aluminium construction.