Outer rotor brushless motor

Abstract

The utility model relates to the technical field of motors, and provides an outer rotor brushless motor which comprises a rotor assembly and a stator assembly. The rotor assembly comprises a rotor shell, an output shaft and a permanent magnet ring, the output shaft is coaxially fixed to the bottom wall of an inner cavity of the rotor shell, and the permanent magnet ring is coaxially fixed to the inner circumference of the rotor shell; the stator assembly comprises a stator core, a stator winding and a circuit board; the stator winding is wound on the stator core, and the stator winding is connected with the circuit board; a supporting sleeve is coaxially fixed to the inner periphery of the stator core and rotationally connected to the output shaft in a sleeving mode through an oil-retaining bearing, and the two ends of the oil-retaining bearing extend to the two ends of the supporting sleeve respectively. The brushless motor has the effect of improving the operation stability of the brushless motor.

Description

Technical Field

[0001] This application relates to the field of electric motors, and more particularly to an external rotor brushless motor. Background Technology

[0002] Currently, electric curtain drive mechanisms generally use external rotor brushless motors as the power source.

[0003] In related technologies, such as Figure 1 The external rotor brushless motor includes a rotor assembly 1 and a stator assembly 2. A support sleeve 23 is usually installed on the inner circumference of the stator core 21 in the stator assembly 2. The front and rear ends of the support sleeve 23 are rotatably connected to the output shaft 12 of the rotor assembly 1 through two ball bearings 20 to achieve axial positioning of the stator assembly 2.

[0004] Regarding the aforementioned technologies, due to the influence of processing and assembly techniques, the coaxiality of the ball bearings at both ends of the support sleeve is prone to deviation, which can easily cause noise and vibration during the operation of the brushless motor, affecting the stability of the brushless motor during subsequent operation. Therefore, there is room for improvement. Utility Model Content

[0005] To improve the stability of brushless motor operation, this application provides an external rotor brushless motor.

[0006] This application provides an external rotor brushless motor, which adopts the following technical solution:

[0007] An external rotor brushless motor includes a rotor assembly and a stator assembly;

[0008] The rotor assembly includes a rotor housing, an output shaft, and a permanent magnet ring. The output shaft is coaxially fixed to the bottom wall of the inner cavity of the rotor housing, and the permanent magnet ring is coaxially fixed to the inner circumference of the rotor housing.

[0009] The stator assembly includes a stator core, a stator winding, and a circuit board; the stator winding is wound around the stator core and connected to the circuit board;

[0010] A support sleeve is coaxially fixed to the inner circumference of the stator core. The support sleeve is rotatably sleeved onto the output shaft via an oil-impregnated bearing. Both ends of the oil-impregnated bearing extend to both ends of the support sleeve.

[0011] By adopting the above technical solution, the support sleeve is rotatably sleeved on the output shaft through an oil-impregnated bearing, and the two ends of the oil-impregnated bearing extend to the two ends of the support sleeve, thereby realizing the stable rotational sleeve of the support sleeve on the output shaft. Compared with the traditional method of the support sleeve being sleeved on the output shaft through two ball bearings, this reduces the vibration and noise problems that are prone to occur when the brushless motor is running due to the coaxiality error of the two ball bearings, which is conducive to improving the stability of the brushless motor during operation, and at the same time simplifies the overall assembly process of the brushless motor.

[0012] Preferably, the oil-impregnated bearing has several grooves on its outer periphery.

[0013] By adopting the above technical solution, oil-impregnated bearings can store lubricating grease in grooves, so that the oil-impregnated bearings can play a more stable lubrication role in the future.

[0014] Preferably, the output shaft is coaxially fitted with two gaskets, which are located at both ends of the oil-impregnated bearing.

[0015] By adopting the above technical solution and setting two gaskets, on the one hand, it is beneficial to limit the friction between the end of the oil-impregnated bearing and the adjacent components, thereby reducing the wear of the oil-impregnated bearing; on the other hand, it is beneficial to limit the entry of external impurities into the gap between the oil-impregnated bearing and the output shaft by using the gaskets.

[0016] Preferably, the output shaft is also coaxially fixed with a limiting ring, which is located at the end of the oil-impregnated bearing away from the fixed end of the output shaft.

[0017] By adopting the above technical solution, the oil-impregnated bearing is axially limited by the limiting ring, which restricts the oil-impregnated bearing from detaching from the output shaft, and helps the oil-impregnated bearing to be more securely fitted onto the output shaft.

[0018] Preferably, the bottom wall of the inner cavity of the rotor housing is coaxially provided with a support protrusion, and the fixed end of the output shaft is coaxially inserted and fixed to the support protrusion.

[0019] By adopting the above technical solution, the contact area between the rotor housing and the output shaft is increased by using the support protrusion, which helps the output shaft to be more stably connected to the rotor housing.

[0020] Preferably, the outer periphery of the support sleeve is provided with a plurality of snap-fit ​​portions, each snap-fit ​​portion including a receiving groove formed on the outer periphery of the support sleeve, wherein an elastic piece is provided in the receiving groove and the elastic piece extends outward at an angle.

[0021] When the support sleeve is coaxially inserted into the inner circumference of the stator core, the elastic sheet abuts against the inner circumference of the stator core.

[0022] By adopting the above technical solution, the support sleeve is coaxially fixed to the inner circumference of the stator core by using the elastic sheet to press against it, which facilitates a stable connection between the support sleeve and the stator core and further simplifies the overall assembly process of the brushless motor.

[0023] Preferably, the stator core has a plurality of pins protruding from one end away from the fixed end of the output shaft, and the stator winding is connected to the pins; the pins pass through the circuit board and are soldered to the circuit board.

[0024] By adopting the above technical solution, the circuit board can be securely installed at the end of the stator core while ensuring the stability and reliability of the electrical connection between the stator winding and the circuit board.

[0025] Preferably, one end of the support sleeve extends out of the rotor housing, and the outer periphery of the end of the support sleeve extending out of the stator core is provided with a protruding edge, and a plurality of connecting lugs are connected to the outer periphery of the protruding edge.

[0026] By adopting the above technical solution, on the one hand, it is beneficial to improve the overall strength of the support sleeve through the protruding edge and connecting lug plate. On the other hand, the brushless motor can be fixed on the external component by connecting the connecting lug plate to the external component.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. The support sleeve on the inner circumference of the stator core is rotatably connected to the output shaft through an oil-impregnated bearing, which makes the support sleeve stably connected to the output shaft, improves the smoothness of the brushless motor during operation, and reduces the noise and vibration caused by coaxiality error of the brushless motor.

[0029] 2. By setting several grooves on the outer periphery of the oil-impregnated bearing, the oil-impregnated grooves can store lubricating grease while improving the heat dissipation effect of the oil-impregnated bearing.

[0030] 3. By setting gaskets at both ends of the oil-impregnated bearing, the oil-impregnated gaskets can restrict external impurities from entering the interior of the oil-impregnated bearing, while also helping to limit friction between the ends of the oil-impregnated bearing and adjacent components. Attached Figure Description

[0031] Figure 1 This is a schematic diagram used in this application to illustrate an existing external rotor brushless motor.

[0032] Figure 2 This is a schematic diagram of the internal structure of an external rotor brushless motor, used in this application.

[0033] Figure 3 This is an exploded schematic diagram used in this application to illustrate an external rotor brushless motor.

[0034] Figure 4 This is a schematic diagram used in this application to illustrate the stator core and circuit board.

[0035] Figure 5 This is a schematic diagram used in this application to illustrate an external rotor brushless motor.

[0036] Figure 6 This is a schematic diagram of the structure of the support sleeve used in this application.

[0037] Figure 7 This is a schematic diagram illustrating the structure of an oil-impregnated bearing, as used in this application.

[0038] Figure 8 yes Figure 2 Enlarged schematic diagram of part A in the middle.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Rotor assembly; 11. Rotor housing; 111. Support protrusion; 12. Output shaft; 13. Permanent magnet ring; 2. Stator assembly; 20. Ball bearing; 21. Stator core; 211. Pin; 22. Circuit board; 23. Support sleeve; 231. Protrusion; 232. Connecting lug; 233. Perforation; 24. Oil-impregnated bearing; 241. Groove; 3. Gasket; 4. Limiting ring; 5. Snap-fit ​​part; 51. Receiving groove; 52. Elastic sheet. Detailed Implementation

[0041] The following is in conjunction with the appendix Figure 2-8 This application will be described in further detail.

[0042] This application discloses an external rotor brushless motor, referring to... Figure 2 and Figure 3 The system comprises a rotor assembly 1 and a stator assembly 2. The rotor assembly 1 includes a rotor housing 11, within which an output shaft 12 and a permanent magnet ring 13 are coaxially supported. The stator assembly 2 includes a stator core 21, stator windings, and a circuit board 22. A support sleeve 23 is coaxially fixed to the inner circumference of the stator core 21, and the support sleeve 23 is rotatably sleeved on the output shaft 12 via an oil-impregnated bearing 24. The stator windings are wound on the stator core 21 and are connected to the circuit board 22.

[0043] The inner wall of the rotor housing 11 opposite to its own opening is the bottom wall of the inner cavity of the rotor housing 11. A support protrusion 111 is coaxially provided on the bottom wall of the inner cavity of the rotor housing 11. In this embodiment, the support protrusion 111 and the rotor housing 11 are integrally die-cast. One end of the output shaft 12 is a fixed end, and the fixed end of the output shaft 12 passes through and is fixed to the bottom wall of the inner cavity of the rotor housing 11 and the support protrusion 111. The support protrusion 111 increases the contact area between the rotor housing 11 and the output shaft 12, which helps to make the output shaft 12 more stably supported in the rotor housing 11. The end of the output shaft 12 away from its fixed end extends out of the rotor housing 11.

[0044] The outer circumference of the permanent magnet ring 13 is interference-fitted with the inner circumference of the rotor housing 11, thereby coaxially fixing the permanent magnet ring 13 to the inner cavity of the rotor housing 11. In other embodiments, the permanent magnet ring 13 can also be bonded and fixed to the inner circumference of the rotor housing 11 using adhesives such as glue.

[0045] Reference Figure 4 and Figure 5 The stator core 21 is located inside the rotor housing 11, and its outer circumference is positioned opposite to the inner circumference of the permanent magnet ring 13. A plurality of pins 211 protrude from the end face of the stator core 21 furthest from the fixed end of the output shaft 12. The stator winding is connected to the pins 211. The end of the pins 211 furthest from the stator core 21 passes through the circuit board 22 and is soldered to the circuit board 22. This arrangement ensures the stability of the connection between the stator winding and the circuit board 22, and also allows the circuit board 22 to be securely mounted at the end of the stator core 21.

[0046] Reference Figure 2 and Figure 6 One end of the support sleeve 23 extends out of the outside of the rotor housing 11, and a protruding edge 231 is provided on the outer periphery of the end of the support sleeve 23 extending out of the rotor housing 11. The protruding edge 231 is arranged opposite to the side of the circuit board 22 that is away from the stator core 21. The provision of the protruding edge 231 helps to improve the overall strength of the end of the support sleeve 23.

[0047] A number of connecting lugs 232 are provided on the outer periphery of the protruding edge 231. When installing and fixing the brushless motor, the connecting lugs 232 on the outer periphery of the protruding edge 231 can be connected to the external components to facilitate the installation and fixing of the brushless motor.

[0048] Reference Figure 4 and Figure 6 The protruding edge 231 has several through holes 233 corresponding to several pins 211 passing through the circuit board 22. All pins 211 pass through the corresponding through holes 233 on the protruding edge 231, which is conducive to the protruding edge 231 being close to the circuit board 22, and facilitates better improvement of the structural compactness of the brushless motor.

[0049] The outer periphery of the support sleeve 23 is provided with several snap-fit ​​portions 5, which are located near the protruding edge 231 of the support sleeve 23 and are evenly distributed around the axis of the support sleeve 23. Each snap-fit ​​portion 5 includes a receiving groove 51 formed on the outer periphery of the support sleeve 23. An elastic piece 52 is connected inside the receiving groove 51. The elastic piece 52 extends outward at an angle from the fixed end near the output shaft 12 toward the fixed end away from the output shaft 12. A gap is left between the elastic piece 52 and the side of the receiving groove 51 near the axial direction of the support sleeve 23. In the initial state, the inclined end of the elastic piece 52 is located outside the receiving groove 51. When the support sleeve 23 is inserted into the inner periphery of the stator core 21, the elastic piece 52 is pressed into the receiving groove 51 by force, and the elastic piece 52 is pressed tightly against the inner periphery of the stator core 21 to fix the support sleeve 23 to the inner periphery of the stator core 21. In other embodiments, the support sleeve 23 can also be glued to the inner circumference of the stator core 21. In this embodiment, both the support sleeve 23 and the elastic sheet 52 are made of plastic and are integrally molded.

[0050] Reference Figure 2 and Figure 7 The oil-impregnated bearing 24 is fitted with the inner circumference of the support sleeve 23 to fix the oil-impregnated bearing 24 to the inner circumference of the support sleeve 23. Both ends of the oil-impregnated bearing 24 extend to both ends of the support sleeve 23, facilitating better support and positioning of the support sleeve 23 and ensuring a more stable fit of the support sleeve 23 onto the output shaft 12. Several grooves 241 are formed on the outer circumference of the oil-impregnated bearing 24; these grooves 241 can store some lubricating grease, which helps the oil-impregnated bearing 24 to perform its lubrication function more stably.

[0051] Reference Figure 2 and Figure 8 Two gaskets 3 are fitted onto the output shaft 12 corresponding to the oil-impregnated bearing 24. The two gaskets 3 abut against the two ends of the oil-impregnated bearing 24, with the gasket 3 near the fixed end of the output shaft 12 abutting against the support protrusion 111. By setting gaskets 3 at both ends of the oil-impregnated bearing 24, it is beneficial to limit the friction between the oil-impregnated bearing 24 and adjacent components. On the other hand, the gaskets 3 can seal the gap between the oil-impregnated bearing 24 and the output shaft 12, preventing external dust and impurities from entering the oil-impregnated bearing 24.

[0052] The output shaft 12 is also fitted with a limiting ring 4, which is interference-fitted with the output shaft 12 to fix the limiting ring 4 on the output shaft 12. The limiting ring 4 is located at the end of the oil-impregnated bearing 24 away from the fixed end of the output shaft 12, and the limiting ring 4 is abutted against the gasket 3 at the end of the oil-impregnated bearing 24. The limiting ring 4 is used to limit the oil-impregnated bearing 24 to prevent it from sliding out of the output shaft 12.

[0053] The implementation principle of this embodiment is as follows: During the assembly of the external rotor brushless motor, the support sleeve 23 with the oil-impregnated bearing 24 is first inserted and fixed to the inner circumference of the stator core 21. Then, the oil-impregnated bearing 24 with the inner circumference of the support sleeve 23 containing the stator core 21, along with two gaskets 3, is fitted onto the output shaft 12. Finally, the limiting ring 4 is pressed into the output shaft 12. Using the oil-impregnated bearing 24 to achieve the rotational connection between the support sleeve 23 and the output shaft 12 of the rotor assembly 1 helps improve the operational stability of the brushless motor and reduces vibration and noise caused by coaxiality errors during operation.

[0054] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An outer rotor brushless motor, comprising a rotor assembly (1) and a stator assembly (2); characterized in that: the rotor assembly (1) comprises a rotor shell (11), an output shaft (12) and a permanent magnet ring (13), the output shaft (12) is coaxially fixed to the bottom wall of the inner cavity of the rotor shell (11), and the permanent magnet ring (13) is coaxially fixed to the inner periphery of the rotor shell (11); the stator assembly (2) comprises a stator core (21), a stator winding and a circuit board (22); the stator winding is wound on the stator core (21), and the stator winding is connected with the circuit board (22); the inner periphery of the stator core (21) is coaxially fixed with a support sleeve (23), the support sleeve (23) is rotatably sleeved on the output shaft (12) through an oil-containing bearing (24), and the oil-containing bearing (24) extends to both ends of the support sleeve (23).

2. An external rotor brushless motor according to claim 1, characterized in that: The outer periphery of the oil-containing bearing (24) is provided with a plurality of grooves (241).

3. An external rotor brushless motor according to claim 1, characterized in that: The output shaft (12) is coaxially sleeved with two gaskets (3), and the two gaskets (3) are located at both ends of the oil-containing bearing (24).

4. An outer rotor brushless motor according to claim 3, characterized in that: The output shaft (12) is also coaxially fixed with a limiting ring (4), and the limiting ring (4) is located at one end of the oil-containing bearing (24) away from the fixed end of the output shaft (12).

5. An external rotor brushless motor according to any one of claims 1-3, characterized in that: The bottom wall of the inner cavity of the rotor shell (11) is coaxially provided with a support protrusion (111), and the fixed end of the output shaft (12) is coaxially inserted into the support protrusion (111).

6. An outer rotor brushless motor according to claim 5, characterized in that: The outer periphery of the support sleeve (23) is provided with a plurality of clamping portions (5), the clamping portion (5) comprises a containing groove (51) provided on the outer periphery of the support sleeve (23), the containing groove (51) is provided with an elastic sheet (52), and the elastic sheet (52) is inclinedly and outwardly extended; When the support sleeve (23) is coaxially inserted into the inner periphery of the stator core (21), the elastic sheet (52) is tightly abutted against the inner periphery of the stator core (21).

7. An outer rotor brushless motor according to claim 5, characterized in that: One end of the stator core (21) away from the fixed end of the output shaft (12) is provided with a plurality of pins (211), the stator winding is connected with the pins (211); the pins (211) are inserted into the circuit board (22), and the pins (211) are tin soldered with the circuit board (22).

8. An outer rotor brushless motor according to claim 6, characterized in that: One end of the support sleeve (23) away from the output shaft (12) extends out of the rotor shell (11), the outer periphery of one end of the support sleeve (23) extending out of the rotor shell (11) is provided with a protruding edge (231), and the outer periphery of the protruding edge (231) is connected with a plurality of connecting ear plates (232).

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