External rotor motor

Abstract

An outer rotor motor comprises a motor shaft extending in the axial direction, an outer rotor assembly fixedly arranged on the motor shaft, an inner stator assembly located between the motor shaft and the outer rotor assembly and a circuit board installed on the inner stator assembly, and the circuit board is electrically connected to the inner stator assembly. The inner stator assembly comprises an inner stator support sleeving the periphery of the motor shaft and an inner stator iron core fixed to the inner stator support. The inner stator support comprises a base located at the axial front end of the inner stator iron core and a main body part extending backwards from the base in the axial direction, and the circuit board is arranged on the main body part in a sleeving mode and located at the axial front end of the inner stator iron core; the circuit board comprises a sleeving part sleeving the periphery of the main body part, the axial front end of the inner stator iron core comprises a boss, and the boss abuts against the axial rear end of the sleeving part to fix the circuit board to the inner stator support. According to the arrangement, the circuit board is fixed through the bosses of the inner stator iron core, the procedure of fixing the circuit board through screwing is reduced, and the assembly process is simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, and particularly to an outer rotor motor. Background Art

[0002] Motors are generally divided into inner rotor motors and outer rotor motors according to the relative positions of the rotor and the stator. Among them, the outer rotor motor relatively has the characteristics of saving space and being compact in design, so it has received more and more extensive attention. A circuit board is usually installed inside the outer rotor motor. The circuit board is placed at the axial rear end of the stator bracket and fixed to the stator bracket by screws, and the installation process is cumbersome.

[0003] In view of this, it is necessary to provide an improved outer rotor motor to overcome the defects existing in the prior art. Summary of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide an outer rotor motor that is convenient for installing a circuit board.

[0005] The technical solution adopted by the utility model to solve the problems of the prior art is: an outer rotor motor, including a motor shaft extending axially, an outer rotor assembly fixed to the motor shaft, an inner stator assembly located between the motor shaft and the outer rotor assembly, and a circuit board installed on the inner stator assembly. The circuit board is electrically connected to the inner stator assembly. The inner stator assembly includes an inner stator bracket sleeved on the outer periphery of the motor shaft and an inner stator core fixed to the inner stator bracket. The inner stator bracket includes a base located at the axial front end of the inner stator core and a main body portion extending axially backward from the base. The circuit board is sleeved on the main body portion and located at the axial front end of the inner stator core. The circuit board includes a sleeved portion sleeved on the outer periphery of the main body portion. The axial front end of the inner stator core includes a convex platform, and the convex platform abuts against the axial rear end of the sleeved portion to fix the circuit board to the inner stator bracket.

[0006] A further improvement scheme is: the circuit board includes a wiring area connected to the sleeved portion and a through hole penetrating the end face of the wiring area. Electronic components and wires are installed in the wiring area.

[0007] A further improvement scheme is: the base protrudes backward from the axial rear end to form a positioning protrusion, and the positioning protrusion is inserted into the through hole to connect the circuit board to the inner stator bracket.

[0008] A further improvement scheme is: the number of the positioning protrusions is the same as that of the through holes and is not less than 2.

[0009] A further improvement scheme is: the axial length of the positioning protrusion is not less than the axial length of the through hole.

[0010] A further improvement solution is as follows: the inner diameter of the sleeve part is greater than the outer diameter of the main body part, and the outer peripheral dimension of the wiring area is smaller than the outer peripheral dimension of the base.

[0011] A further improvement solution is as follows: the boss is integrally injection-molded on the end face of the inner stator core.

[0012] A further improvement solution is as follows: the boss is in a circular ring shape, and the size of the boss is adapted to the size of the sleeve part so that the boss abuts against the rear end face of the sleeve part.

[0013] A further improvement solution is as follows: the front end face of the circuit board is attached to the rear end face of the base.

[0014] Compared with the prior art, the present utility model has the following beneficial effects: the circuit board includes a sleeve part sleeved on the outer periphery of the main body part, the axial front end of the inner stator core includes a boss, and the boss abuts against the axial rear end of the sleeve part to fix the circuit board to the inner stator bracket. With such a setting, the circuit board is fixed by the boss of the inner stator core, reducing the process of fixing the circuit board with screws and simplifying the assembly process. [Description of the Drawings]

[0015] The following further describes in detail the specific embodiments of the present utility model with reference to the drawings:

[0016] Figure 1 is a perspective view of the outer rotor motor of the present utility model;

[0017] Figure 2 is Figure 1 the sectional view of the outer rotor motor shown;

[0018] Figure 3 is Figure 2 the exploded view of the outer rotor motor shown;

[0019] Figure 4 is Figure 3 the perspective view of the inner stator assembly and the circuit board of the outer rotor motor shown;

[0020] Figure 5 is Figure 3 the perspective view of the outer rotor assembly of the outer rotor motor shown;

[0021] Figure 6 is Figure 5 the sectional view of the outer rotor assembly of the outer rotor motor shown;

[0022] Figure 7 is Figure 3 the perspective view of the circuit board of the outer rotor motor shown;

[0023] Figure 8 is Figure 3 a three-dimensional schematic view of the magnet fixing bracket of the outer rotor motor shown in the figure.

[0024] The meanings of the reference numerals in the figure are as follows:

[0025] Outer rotor motor 100, motor shaft 1

[0026] Front bearing 10, rear bearing 11

[0027] Circlip 12, outer rotor assembly 2

[0028] Outer rotor housing 20, annular wall 201

[0029] End wall 202, ventilation hole 203

[0030] Magnet fixing bracket 21, mounting portion 211

[0031] Limit block 212, stop ring 213

[0032] Magnet 22, inner stator assembly 3

[0033] Inner stator bracket 30, base 301

[0034] Main body portion 302, supporting portion 303

[0035] Positioning protrusion 304, inner stator core 31

[0036] Boss 311, coil winding 32

[0037] Circuit board 4, sleeving portion 40

[0038] Wiring area 41, through hole 42

[0039] Fan 5, blower housing 6 [Specific embodiments]

[0040] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For example, the terms such as "upper", "lower", "front", "rear" indicating the orientation or position relationship are only based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0041] Please refer to Figures 1 to 8The present utility model relates to an external rotor motor 100, which is usually used to be connected to a power tool. The external rotor motor 100 has the characteristics of being convenient for operation and maintenance, simple and feasible to assemble, compact in structure, reliable in operation, environmentally friendly and economical. The external rotor motor 100 includes a motor shaft 1 extending axially, an external rotor assembly 2 connected to the motor shaft 1, and an internal stator assembly 3 located between the motor shaft 1 and the external rotor assembly 2. The motor shaft 1 rotates with the external rotor assembly 2 relative to the internal stator assembly 3.

[0042] Please refer to Figure 2 and Figure 3 As shown, the external rotor assembly 2 has an external rotor housing 20 that houses the internal stator assembly 3. The external rotor housing 20 includes an annular wall 201 sleeved on the outer periphery of the internal stator assembly 3 and an end wall 202 located on the axial rear side of the annular wall 201. The annular wall 201 extends axially forward from the peripheral side of the end wall 202. The motor shaft 1 is held by the end wall 202.

[0043] Furthermore, the external rotor assembly 2 includes several ventilation holes 203 opened on the end wall 202. The ventilation holes 203 are used for allowing external air to flow through to dissipate heat from the external rotor motor 100. The number of the ventilation holes 203 is 6, and the shape is circular and arranged around the center of the end wall 202, which not only ensures the air volume of the external air but also makes the appearance beautiful. Preferably, the number of the ventilation holes 203 can be one or more, and the shape can be any shape or a combination of different shapes.

[0044] The external rotor housing 20 can be cylindrical, and its inner diameter is larger than the outer diameter of the internal stator assembly 3. One end of the external rotor housing 20 is open, and the internal stator assembly 3 can penetrate through it. In this embodiment, the external rotor housing 20 is made of a metal material. It can be understood that in other alternative embodiments, the external rotor housing 20 can be formed of other materials.

[0045] Please refer to Figures 2 to 4As shown, the inner stator assembly 3 includes an inner stator bracket 30 sleeved on the outer periphery of the motor shaft 1, an inner stator core 31 fixed to the inner stator bracket 30, and several coil windings 32 wound around the inner stator core 31; the inner stator core 31 is cylindrical and has a hollow structure with both ends penetrating, and it is made by stamping a plurality of sheet-shaped steel sheets. An inner stator plastic coating (not shown) is provided between the teeth and slots (not shown) of the inner stator core 31, and the inner stator plastic coating can separate different teeth and play an insulating role. The coil windings 32 are wound around the teeth of the inner stator core 31 through the inner stator plastic coating, the coil windings 32 are arranged corresponding to the teeth, the coil windings 32 can be multiple groups, and the coil windings 32 can generate electromagnetic induction when energized.

[0046] When winding the coil windings 32, a fly fork method can be used by a winding machine to wind each inner stator core 31 independently. After the winding is completed, the wire ends are welded. By operating in this way, not only the process is simple and easy to operate, but also a high slot fill factor can be achieved.

[0047] Further, the motor shaft 1 can be cylindrical, and its length is greater than the length of the inner stator assembly 3. One end of the motor shaft 1 passes through the inner stator bracket 30 and is rotatably connected to the inner stator bracket 30, and the other end of the motor shaft 1 passes through the end wall 202 and is rotatably connected to the outer rotor housing 20.

[0048] The inner stator bracket 30 includes a base 301 at the axial front end of the inner stator core 31, a main body portion 302 extending axially backward from the base 301, and a support portion 303 extending axially backward from the main body portion 302. The outer diameter of the main body portion 302 is different from the outer diameter of the support portion 303, and the inner stator bracket 30 is integrally injection molded with aluminum metal.

[0049] The outer rotor motor 100 further includes a circuit board 4 mounted on the inner stator assembly 3, and the circuit board 4 is used to control the operation of the outer rotor motor 100; the circuit board 4 is sleeved on the main body portion 302 and is located at the axial front end of the inner stator core 31, and the front end face of the circuit board 4 is attached to the rear end face of the base 301.

[0050] Specifically, please refer to Figure 7, the circuit board 4 includes a sleeved portion 40 sleeved on the outer periphery of the main body portion 302. The axial front end of the inner stator core 31 includes a boss 311, and the boss 311 abuts against the axial rear end of the sleeved portion 40 to fix the circuit board 4 to the inner stator bracket 30; the sleeved portion 40 is preferably arranged in a ring shape, and the boss 311 is integrally injection-molded on the front end face of the inner stator core 31; the boss 311 is in a circular ring shape, and the size of the boss 311 is adapted to the size of the sleeved portion 40 so that the boss 311 abuts against the axial rear end face of the sleeved portion 40.

[0051] Further, the circuit board 4 includes a wiring area 41 connected to the sleeved portion 40 and a through hole 42 penetrating the end face of the wiring area 41. Electronic components and wires are installed in the wiring area 41; the base 301 protrudes rearward from the axial rear end to form a positioning protrusion 304, and the positioning protrusion 304 is inserted into the through hole 42 to connect the circuit board 4 to the inner stator bracket 30; the inner diameter of the sleeved portion 40 is larger than the outer diameter of the main body portion 302, and the outer peripheral dimension of the wiring area 41 is smaller than the outer peripheral dimension of the base 301; the number of the positioning protrusions 304 is the same as that of the through holes 42 and is not less than 2; the axial length of the positioning protrusion 304 is not less than the axial length of the through hole 42.

[0052] Through the cooperation of the positioning protrusion 304 and the through hole 42, the circuit board 4 is stably and reliably connected to the inner stator bracket 30, and the circuit board 4 will not move relative to the inner stator bracket 30 during the operation of the outer rotor motor 100.

[0053] Please refer to Figure 3 、 Figure 5 and Figure 6 As shown in, the outer rotor assembly 2 includes two magnet fixing frames 21 attached to the annular wall 201 and a magnet 22 installed between the two magnet fixing frames 21. The two magnet fixing frames 21 are respectively located at the axial two ends of the annular wall 201 and are arranged facing each other. The outer diameter of the magnet fixing frame 21 is not less than the inner diameter of the annular wall 201; the magnet fixing frame 21 is installed on the outer rotor housing 20 by an interference fit, and the magnet 22 can be firmly attached to the inner wall of the annular wall 201; the magnet fixing frame 21 is integrally formed by plastic.

[0054] The magnet 22 is located on the outer periphery in diameter of the inner stator core 31. The magnet 22 cooperates with the inner stator assembly 3 through electromagnetic induction to convert electrical energy into mechanical energy, so that it rotates itself and drives the outer rotor housing 20 to rotate, and further drives the motor shaft 1 to rotate.

[0055] The shape of the permanent magnet 22 can be tile-shaped, square, etc. The permanent magnet 22 is one of alnico permanent magnets, ferrite permanent magnets, and neodymium iron boron permanent magnets. Of course, the type of the permanent magnet 22 is not limited to the three mentioned above, and those skilled in the art can also select other types of the permanent magnet 22 according to the actual situation and needs; the number of the permanent magnets 22 can be selected according to the design requirements, and the shape can be any shape.

[0056] Please refer to Figure 8 As shown, the permanent magnet fixing frame 21 includes a mounting portion 211 for placing the permanent magnet 22, a limiting block 212 located between two adjacent mounting portions 211, and a retaining ring 213 extending axially from the inner edge of the mounting portion 211; the retaining ring 213 is located on the radially inner circumference of the permanent magnet 22, and the two retaining rings 213 abut against the side walls at both axial ends of the permanent magnet 22. The retaining ring 213 performs radial limiting on the permanent magnet 22 to prevent the permanent magnet 22 from disengaging from the permanent magnet fixing frame 21. Preferably, the axial length of the retaining ring 213 is not less than 3 mm, which can ensure the limiting effect.

[0057] The permanent magnet 22 is located between two adjacent limiting blocks 212 in the circumferential direction. The limiting blocks 212 are evenly distributed in the circumferential direction on the permanent magnet fixing frame 21. The limiting blocks 212 are provided to perform circumferential limiting on the permanent magnet 22, and the end of the mounting portion 211 performs axial limiting on the end of the permanent magnet 22.

[0058] In this embodiment, first place a permanent magnet fixing frame 21 at the axial rear end of the outer rotor housing 20, then place the permanent magnet 22 into the mounting portion 211, and finally place a permanent magnet fixing frame 21 at the axial front end of the permanent magnet 22; with such a setting, the permanent magnet 22 can be reliably attached to the inner wall of the annular wall 201. It is necessary to apply glue to attach the permanent magnet 22 to the annular wall 201. The process is simple, and the fixing effect of the permanent magnet fixing frame 21 is good.

[0059] The outer rotor motor 100 further includes a wind cover housing 6 sleeved on the outer periphery of the outer rotor assembly 2. The wind cover housing 6 is located at the axial rear end of the base 301, and the wind cover housing 6 is fixed to the inner stator bracket 30 by screws.

[0060] The outer rotor motor 100 is provided with a front bearing 10 and a rear bearing 11 at both axial ends of the motor shaft 1. The front bearing 10 is received at the axial front end of the inner stator bracket 30, and the motor shaft 1 is supported in the inner stator bracket 30 through the front bearing 10. The rear bearing 11 is received in the inner circumference of the wind cover housing 6, and the motor shaft 1 is supported in the wind cover housing 6 through the rear bearing.

[0061] Furthermore, a retaining ring 12 is mounted on the axial front end of the motor shaft 1. The retaining ring 12 is clamped on the motor shaft 1 and is located on a section where the motor shaft 1 passes through the inner stator bracket 30. Specifically, the retaining ring 12 is disposed close to the front bearing 10 to prevent the front bearing 10 from coming off the motor shaft 1. A gasket (not shown) is further disposed between the front bearing 10 and the retaining ring 12, and the gasket can be used to prevent mutual friction and wear between the front bearing 10 and the retaining ring 12.

[0062] The outer rotor motor 100 further includes a fan 5 mounted on the axial rear end of the motor shaft 1. The fan 5 is located at the axial front end of the rear bearing 11, and the fan 5 is used to allow external gas to flow into the interior of the outer rotor motor 100, playing a role in heat dissipation and cooling.

[0063] In this embodiment, the circuit board 4 includes a sleeved portion 40 sleeved on the outer periphery of the main body portion 302. The axial front end of the inner stator core 31 includes a boss 311, and the boss 311 abuts against the axial rear end of the sleeved portion 40 to fix the circuit board 4 to the inner stator bracket 30. With such a setting, the circuit board 4 is fixed by the boss 311 of the inner stator core 31, reducing the process of screwing to fix the circuit board 4 and simplifying the assembly process.

[0064] The present utility model is not limited to the above specific embodiments. Those of ordinary skill in the art can easily understand that there are many alternative solutions for the outer rotor motor of the present utility model without departing from the principles and scopes of the present utility model. The protection scope of the present utility model shall be subject to the content of the claims.

Claims

1. An outer rotor motor, comprising a motor shaft extending in an axial direction, an outer rotor assembly fixed on the motor shaft, an inner stator assembly located between the motor shaft and the outer rotor assembly, and a circuit board mounted on the inner stator assembly, wherein the circuit board is electrically connected to the inner stator assembly, the inner stator assembly comprises an inner stator bracket sleeved on the outer periphery of the motor shaft and an inner stator core fixed to the inner stator bracket; the inner stator bracket comprises a base located at the axial front end of the inner stator core and a main body extending axially backward from the base, the circuit board is sleeved on the main body and located at the axial front end of the inner stator core; characterized in that: The circuit board includes a sleeve portion sleeved on the outer periphery of the main body, and the axial front end of the inner stator core includes a boss, which abuts against the axial rear end of the sleeve portion to fix the circuit board to the inner stator bracket.

2. The outer rotor motor according to claim 1, characterized in that: The circuit board comprises a wiring area connected to the sleeve portion and a through hole penetrating an end surface of the wiring area, and the wiring area is provided with electronic components and wires.

3. The outer rotor motor according to claim 2, characterized in that: The base protrudes backward from the axial rear end to form a positioning protrusion, and the positioning protrusion is inserted into the through hole to connect the circuit board to the inner stator bracket.

4. The outer rotor motor according to claim 3, characterized in that: The number of the positioning protrusions is the same as the number of the through holes and is no less than 2.

5. The outer rotor motor according to claim 3, characterized in that: The axial length of the positioning protrusion is not less than the axial length of the through hole.

6. The outer rotor motor according to claim 2, characterized in that: The inner diameter of the sleeve portion is larger than the outer diameter of the main body portion, and the outer circumference of the wiring area is smaller than the outer circumference of the base.

7. The outer rotor motor according to claim 1, characterized in that: The boss is integrally injection-molded on the end surface of the inner stator core.

8. The outer rotor motor according to claim 1, characterized in that: The boss is annular, and the size of the boss is matched with the size of the sleeve portion so that the boss abuts against the rear end surface of the sleeve portion.

9. The outer rotor motor according to claim 1, characterized in that: The front end surface of the circuit board is attached to the rear end surface of the base.

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