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 and an inner stator assembly located between the motor shaft and the outer rotor assembly, and the outer rotor assembly comprises an outer rotor machine shell containing the inner stator assembly and a plurality of pieces of magnetic steel attached to the inner wall of the outer rotor machine shell; the outer rotor casing comprises an annular wall sleeving the periphery of the inner stator assembly and an end wall located on the axial rear side of the annular wall, the motor shaft is fixedly held on the end wall, and the annular wall extends in the axial direction from the circumferential side of the end wall; the outer rotor assembly comprises two magnetic steel fixing frames attached to the annular wall, the magnetic steel is installed between the two magnetic steel fixing frames, and the two magnetic steel fixing frames are located at the two axial ends of the annular wall respectively. By arranging the two magnetic steel fixing frames, the magnetic steel can be reliably attached to the annular wall, and axial and radial movement of the magnetic steel is avoided; and one surface of the magnetic steel does not need to be glued, so that the technological process is simplified.

Description

[Technical field]

[0001] The utility model relates to the technical field of motors, in particular to an outer rotor motor. [Background Technology]

[0002] According to the relative position of the rotor and stator, the motor is usually divided into inner rotor motor and outer rotor motor. Among them, the outer rotor motor is relatively space-saving and compact in design, so it has received more and more attention. The traditional outer rotor motor magnet assembly method is: place a plastic bracket inside the outer rotor housing, and then install the magnet into the groove of the plastic bracket. The magnet is tightly attached to the inner wall of the outer rotor housing through glue. The fixation of the magnet mainly depends on glue. When the outer rotor motor resonates, the glue is easy to fall off due to vibration, making the outer rotor motor fail; at the same time, the use of glue for pasting will complicate the process flow.

[0003] In view of this, it is indeed necessary to provide an improved outer rotor motor to overcome the defects of the prior art. [Contents of the utility model]

[0004] In view of the deficiencies in the prior art, the purpose of the utility model is to provide an outer rotor motor with good magnetic steel fixing effect.

[0005] The utility model adopts the following technical solution to solve the problems of the prior art: an outer rotor motor, comprising an axially extending motor shaft, an outer rotor assembly fixed on the motor shaft, and an inner stator assembly located between the motor shaft and the outer rotor assembly, wherein the outer rotor assembly comprises an outer rotor casing for accommodating the inner stator assembly and a plurality of magnets attached to the inner wall of the outer rotor casing; the outer rotor casing comprises an annular wall sleeved on the outer periphery of the inner stator assembly and an end wall located on the axial rear side of the annular wall, the motor shaft is fixed on the end wall, and the annular wall extends axially from the circumferential side of the end wall; the outer rotor assembly comprises two magnet fixing frames attached to the annular wall, the magnet is installed between the two magnet fixing frames, and the two magnet fixing frames are respectively located at the axial ends of the annular wall.

[0006] A further improvement is that the two magnetic steel fixing frames are arranged facing each other.

[0007] A further improvement is as follows: the magnetic steel fixing frame includes a mounting portion for placing the magnetic steel, a limit block located between two adjacent mounting portions, and a stop ring extending axially from the inner edge of the mounting portion, and the magnetic steel abuts against the stop ring.

[0008] A further improved solution is: the stop ring is located at the radial inner periphery of the magnetic steel, and the two stop rings are abutted against the side walls at the axial ends of the magnetic steel.

[0009] A further improvement is that the axial length of the stop ring is not less than 3 mm.

[0010] A further improved solution is: the magnetic steel is located between two adjacent limit blocks in the circumferential direction, and the limit blocks are evenly distributed on the magnetic steel fixing frame along the circumferential direction.

[0011] A further improvement is that the outer diameter of the magnetic steel fixing frame is not less than the inner diameter of the annular wall.

[0012] A further improvement is that the magnetic steel fixing frame is integrally formed of plastic.

[0013] A further improved solution is: the inner stator assembly includes an inner stator bracket sleeved on the outer circumference of the motor shaft and an inner stator core fixed to the inner stator bracket, the magnetic steel is located radially outside the inner stator core, and the magnetic steel is arranged around the inner stator core.

[0014] Compared with the prior art, the utility model has the following beneficial effects: the outer rotor assembly includes two magnetic steel fixing frames attached to the annular wall, the magnetic steel is installed between the two magnetic steel fixing frames, and the two magnetic steel fixing frames are respectively located at the axial ends of the annular wall; by setting up two magnetic steel fixing frames, the magnetic steel can be reliably attached to the annular wall, and the magnetic steel will not produce axial and radial movement; and there is no need to apply glue on one side of the magnetic steel, which simplifies the process flow. [Drawings]

[0015] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings:

[0016] Figure 1 It is a three-dimensional schematic diagram of the outer rotor motor of the utility model;

[0017] Figure 2 yes Figure 1 A cross-sectional view of an outer rotor motor is shown;

[0018] Figure 3 yes Figure 2 An exploded view of an outer rotor motor is shown;

[0019] Figure 4 yes Figure 3 A three-dimensional schematic diagram of an inner stator assembly and a circuit board of an outer rotor motor shown;

[0020] Figure 5 yes Figure 3 A three-dimensional schematic diagram of an outer rotor assembly of an outer rotor motor shown;

[0021] Figure 6 yes Figure 5 A cross-sectional view of an outer rotor assembly of an outer rotor motor shown;

[0022] Figure 7 yes Figure 3 A three-dimensional schematic diagram of a circuit board of an outer rotor motor shown;

[0023] Figure 8 yes Figure 3 The three-dimensional schematic diagram of the magnetic steel fixing frame of the outer rotor motor shown.

[0024] Meaning of the reference numerals in the figures:

[0025] External rotor motor 100 Motor shaft 1

[0026] Front bearing 10 Rear bearing 11

[0027] Retaining ring 12 Outer rotor assembly 2

[0028] Outer rotor housing 20 annular wall 201

[0029] End wall 202 Ventilation hole 203

[0030] Magnetic steel fixing frame 21 mounting portion 211

[0031] Limit block 212 Stop ring 213

[0032] Magnetic steel 22 Inner stator assembly 3

[0033] Inner stator bracket 30 base 301

[0034] Main body part 302 Support part 303

[0035] Positioning protrusion 304 Inner stator core 31

[0036] Boss 311 Coil winding 32

[0037] Circuit board 4 Set part 40

[0038] Wiring area 41 Through hole 42

[0039] Fan 5 Fan cover housing 6 [Specific implementation method]

[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 words "upper", "lower", "front", "back", etc., which indicate the orientation or position relationship, are 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, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0041] See also Figures 1 to 8 The figure shows an outer rotor motor 100 involved in the utility model, which is usually used to be connected to an electric tool. The outer rotor motor 100 has the characteristics of convenient operation and maintenance, simple and feasible assembly, compact structure, reliable operation, environmental protection and economy, etc. The outer rotor motor 100 includes a motor shaft 1 extending in the axial direction, an outer rotor assembly 2 connected to the motor shaft 1, and an inner stator assembly 3 located between the motor shaft 1 and the outer rotor assembly 2. The motor shaft 1 rotates relative to the inner stator assembly 3 along with the outer rotor assembly 2.

[0042] See also Figure 2 and Figure 3 As shown, the outer rotor assembly 2 has an outer rotor housing 20 for accommodating the inner stator assembly 3, and the outer rotor housing 20 includes an annular wall 201 sleeved on the outer periphery of the inner 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 circumferential side of the end wall 202, and the motor shaft 1 is fixed to the end wall 202.

[0043] Furthermore, the outer rotor assembly 2 includes a plurality of ventilation holes 203 provided on the end wall 202, and the ventilation holes 203 are used for allowing external air to flow through to dissipate heat for the outer rotor motor 100; the number of the ventilation holes 203 is 6, which are circular in shape and are arranged around the center of the end wall 202, which not only ensures the air volume of the external air, but also makes the shape 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 outer rotor housing 20 may be cylindrical, and its inner diameter is larger than the outer diameter of the inner stator assembly 3; one end of the outer rotor housing 20 is open, and the inner stator assembly 3 can be inserted therein. In this embodiment, the outer rotor housing 20 is made of metal material, and it can be understood that in other alternative embodiments, the outer rotor housing 20 may be made of other materials.

[0045] See also 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 a plurality of coil windings 32 wound on the inner stator core 31; the inner stator core 31 is cylindrical and is a hollow structure with two ends through, and is made by stamping a plurality of sheet-like steel sheets. An inner stator plastic package (not shown) is arranged between the tooth slots (not shown) of the inner stator core 31, and the inner stator plastic package can separate different teeth and play an insulating role. The coil winding 32 is wound on the tooth portion of the inner stator core 31 through the inner stator plastic package, and the coil winding 32 is arranged corresponding to the tooth portion. The coil winding 32 can be a plurality of groups, and the coil winding 32 can generate electromagnetic induction when powered on.

[0046] When winding the coil winding 32, a winding machine can be used to independently wind each inner stator core 31 using a flying fork method. After the winding is completed, the wire ends are welded. This operation is not only simple in process and easy to operate, but also can achieve a higher slot fill rate.

[0047] Furthermore, the motor shaft 1 may 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 located at the axial front end of the inner stator core 31, a main body 302 extending axially backward from the base 301, and a support portion 303 extending axially backward from the main body 302. The outer diameter of the main body 302 is different from the outer diameter of the support portion 303. The inner stator bracket 30 is integrally formed by aluminum metal injection molding.

[0049] The outer rotor motor 100 also includes a circuit board 4 installed 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 302 and located at the axial front end of the inner stator core 31, and the front end surface of the circuit board 4 is attached to the rear end surface of the base 301.

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

[0051] Furthermore, the circuit board 4 includes a wiring area 41 connected to the sleeve portion 40 and a through hole 42 penetrating the end surface of the wiring area 41, and the wiring area 41 is installed with electronic components and wires; the base 301 protrudes from the axial rear end to the 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 sleeve portion 40 is larger than the outer diameter of the main body 302, and the outer circumferential dimension of the wiring area 41 is smaller than the outer circumferential 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] The positioning protrusion 304 cooperates with the through hole 42 to stably and reliably connect the circuit board 4 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] See also Figure 3 , Figure 5 and Figure 6 As shown, the outer rotor assembly 2 includes two magnetic steel fixing frames 21 attached to the annular wall 201 and a magnetic steel 22 installed between the two magnetic steel fixing frames 21. The two magnetic steel fixing frames 21 are respectively located at the axial ends of the annular wall 201 and are arranged opposite to each other. The outer diameter of the magnetic steel fixing frame 21 is not less than the inner diameter of the annular wall 201; the magnetic steel fixing frame 21 is installed to the outer rotor housing 20 by interference fit, and the magnetic steel 22 can be firmly attached to the inner wall of the annular wall 201; the magnetic steel fixing frame 21 is integrally formed of plastic.

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

[0055] The shape of the magnetic steel 22 can be tile-shaped, square, etc. The magnetic steel 22 is one of aluminum nickel cobalt magnetic steel, ferrite magnetic steel and neodymium iron boron magnetic steel. Of course, the type of the magnetic steel 22 is not limited to the three types mentioned above. Those skilled in the art can also choose other types of the magnetic steel 22 according to actual conditions and needs; the number of the magnetic steel 22 can be selected according to design requirements, and the shape can be any shape.

[0056] Please combine Figure 8 As shown, the magnetic steel fixing frame 21 includes a mounting portion 211 for placing the magnetic steel 22, a limiting block 212 located between two adjacent mounting portions 211, and a stop ring 213 extending axially from the inner edge of the mounting portion 211; the stop ring 213 is located at the radial inner periphery of the magnetic steel 22, and the two stop rings 213 abut against the side walls at both axial ends of the magnetic steel 22, and the stop ring 213 radially limits the magnetic steel 22 to prevent the magnetic steel 22 from falling out of the magnetic steel fixing frame 21. Preferably, the axial length of the stop ring 213 is not less than 3 mm, which can ensure the limiting effect.

[0057] The magnetic steel 22 is located between two adjacent limit blocks 212 in the circumferential direction. The limit blocks 212 are evenly distributed on the magnetic steel fixing frame 21 along the circumferential direction. The limit blocks 212 are provided to circumferentially limit the magnetic steel 22. The end of the mounting portion 211 axially limits the end of the magnetic steel 22.

[0058] In this embodiment, a magnetic steel fixing frame 21 is first placed at the axial rear end of the outer rotor housing 20, and then the magnetic steel 22 is placed in the mounting portion 211, and finally a magnetic steel fixing frame 21 is placed at the axial front end of the magnetic steel 22; in this way, the magnetic steel 22 can be reliably attached to the inner wall of the annular wall 201, and glue needs to be applied to attach the magnetic steel 22 to the annular wall 201. The process is simple, and the fixing effect of the magnetic steel fixing frame 21 is good.

[0059] The outer rotor motor 100 further includes a fan housing 6 sleeved on the outer periphery of the outer rotor assembly 2 , the fan housing 6 is located at the axial rear end of the base 301 , and the fan 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 located at both axial ends of the motor shaft 1. The front bearing 10 is accommodated in 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 accommodated in the inner periphery of the fan housing 6, and the motor shaft 1 is supported in the fan housing 6 through the rear bearing.

[0061] Furthermore, a retaining ring 12 is installed at the axial front end of the motor shaft 1, and the retaining ring 12 is clamped on the motor shaft 1. The retaining ring 12 is located on a section of the motor shaft 1 that passes through the inner stator bracket 30. Specifically, the retaining ring 12 is arranged close to the front bearing 10 to prevent the front bearing 10 from slipping out of the motor shaft 1; a gasket (not shown) is also arranged between the front bearing 10 and the retaining ring 12, and the gasket can be used to prevent the front bearing 10 and the retaining ring 12 from rubbing against each other and causing wear.

[0062] The outer rotor motor 100 further includes a fan 5 mounted to the axial rear end of the motor shaft 1. The fan 5 is located at the axial front end of the rear bearing 11. The fan 5 is used to allow external air to flow into the interior of the outer rotor motor 100 to dissipate heat and cool the motor.

[0063] In this embodiment, the outer rotor assembly 2 includes two magnetic steel fixing frames 21 attached to the annular wall 201, and the magnetic steel 22 is installed between the two magnetic steel fixing frames 21. The two magnetic steel fixing frames 21 are respectively located at the axial ends of the annular wall 201. By setting up two magnetic steel fixing frames 21, the magnetic steel 22 can be reliably attached to the annular wall 201, and the magnetic steel 22 will not produce axial and radial movement. There is no need to apply glue on one side of the magnetic steel 22, which simplifies the process flow.

[0064] The utility model is not limited to the above specific implementations. Those skilled in the art can easily understand that there are many alternatives to the outer rotor motor of the utility model without departing from the principle and scope of the utility model. The protection scope of the utility model shall be based on 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 to the motor shaft, and an inner stator assembly located between the motor shaft and the outer rotor assembly, wherein the outer rotor assembly comprises an outer rotor housing for accommodating the inner stator assembly and a plurality of magnetic steels attached to the inner wall of the outer rotor housing; the outer rotor housing comprises an annular wall sleeved on the outer periphery of the inner stator assembly and an end wall located at the axial rear side of the annular wall, the motor shaft is fixed to the end wall, and the annular wall extends in an axial direction from the circumferential side of the end wall; characterized in that: The outer rotor assembly includes two magnetic steel fixing frames attached to the annular wall, the magnetic steel is installed between the two magnetic steel fixing frames, and the two magnetic steel fixing frames are respectively located at two axial ends of the annular wall.

2. The outer rotor motor according to claim 1, characterized in that: The two magnetic steel fixing frames are arranged facing each other.

3. The outer rotor motor according to claim 1, characterized in that: The magnetic steel fixing frame includes a mounting portion for placing the magnetic steel, a limiting block located between two adjacent mounting portions, and a stop ring extending axially from the inner edge of the mounting portion, and the magnetic steel abuts against the stop ring.

4. The outer rotor motor according to claim 3, characterized in that: The stop ring is located at the radial inner periphery of the magnetic steel, and the two stop rings are abutted against the side walls at the axial ends of the magnetic steel.

5. The outer rotor motor according to claim 4, characterized in that: The axial length of the stop ring is not less than 3 mm.

6. The outer rotor motor according to claim 3, characterized in that: The magnetic steel is located between two adjacent limit blocks in the circumferential direction, and the limit blocks are evenly distributed on the magnetic steel fixing frame along the circumferential direction.

7. The outer rotor motor according to claim 1, characterized in that: The outer diameter of the magnetic steel fixing frame is not less than the inner diameter of the annular wall.

8. The outer rotor motor according to claim 7, characterized in that: The magnetic steel fixing frame is integrally formed of plastic.

9. The outer rotor motor according to claim 1, characterized in that: The inner stator assembly includes an inner stator bracket sleeved on the outer circumference of the motor shaft and an inner stator core fixed to the inner stator bracket. The magnetic steel is located radially outside the inner stator core and is arranged around the inner stator core.

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