External rotor motor

Abstract

An outer rotor motor includes an axially extending motor shaft, an outer rotor assembly that holds the motor shaft, and an inner stator assembly located between the motor shaft and the outer rotor assembly, wherein the inner stator assembly includes an inner stator bracket that is sleeved on the outer periphery of the motor shaft and an inner stator core that is fixed to the inner stator bracket, wherein the inner stator bracket includes a base located at the axial front end of the inner stator core and a support portion that extends axially backward from the base, and the inner stator core is sleeved on the outer periphery of the support portion; the inner stator assembly includes a connector located between the inner peripheral wall of the inner stator core and the outer surface of the support portion, wherein the connector is integrally formed between the support portion and the inner stator core by a mass-molded plastic. In such a configuration, the connector separates the support portion and the inner stator core, so that an insulating structure is formed between the two, and the connector can ensure the matching strength between the two; at the same time, there is no need to fine-process the support portion, which can simplify the process and reduce costs.

Description

[Technical field]

[0001] The utility model relates to the technical field of outer rotor motors, in particular to an outer rotor motor with an improved inner stator core installation method. [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. Most traditional outer rotor motors press the stator core onto the stator bracket by interference fit to ensure that the bonding force between the two meets the working conditions of the outer rotor motor. However, the stator bracket is made of aluminum and cannot meet the insulation requirements under high voltage; if the stator bracket is made of plastic, it cannot meet the high-power working requirements of the outer rotor motor.

[0003] When the outer rotor motor is in harsh working conditions such as high-power operation, the stator core may be at risk of axial movement, which will cause the performance of the outer rotor motor to deteriorate or even cause the rotor and stator to rub against each other and damage parts. At the same time, the stator bracket and the stator core are fitted with an interference fit, which places high demands on the production tooling and workpiece dimensional accuracy, which can easily lead to poor concentricity between the two and affect product quality.

[0004] 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]

[0005] In view of the deficiencies in the prior art, the purpose of the utility model is to provide an outer rotor motor, in which an inner stator core and an inner stator bracket of the outer rotor motor are tightly connected by a connecting piece formed by injection molding of a mass-molded plastic, thereby ensuring the matching strength of the two, improving the insulation effect and saving costs.

[0006] 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 that fixes the motor shaft, and an inner stator assembly located between the motor shaft and the outer rotor assembly, wherein 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, wherein the inner stator bracket comprises a base located at the axial front end of the inner stator core and a support portion that extends axially backward from the base, wherein the inner stator core is sleeved on the outer periphery of the support portion; wherein the inner stator assembly comprises a connecting piece located between the inner peripheral wall of the inner stator core and the outer surface of the support portion, wherein the connecting piece is integrally formed of a mass-molded plastic between the support portion and the inner stator core.

[0007] A further improved solution is: the outer periphery of the supporting portion includes a first combining portion, the inner periphery of the connecting member includes a second combining portion, and the second combining portion is fitted to the first combining portion.

[0008] A further improved solution is that the shapes of the first combining portion and the second combining portion are adapted to each other, and one of the first combining portion and the second combining portion is configured as a protrusion, and the other is configured as a depression.

[0009] A further improved solution is: the inner surface of the connecting member is attached to the outer surface of the supporting portion, and the inner circumferential wall of the inner stator core is attached to the outer surface of the connecting member.

[0010] A further improved solution is: the inner stator assembly includes an insulating gasket sleeved on the outer periphery of the support portion, and the insulating gasket is located between the base and the inner stator core in the front-to-back direction.

[0011] A further improvement is that the size and shape of the inner periphery of the insulating gasket match the size and shape of the outer periphery of the supporting portion; the size and shape of the outer periphery of the insulating gasket match the size and shape of the inner periphery of the inner stator core.

[0012] A further improvement is that the thickness of the insulating gasket is not less than 2 mm.

[0013] A further improvement is as follows: the outer rotor assembly includes an outer rotor housing for accommodating the inner stator assembly, the outer rotor housing is provided with an annular wall sleeved on the outer periphery of the inner stator core and an end wall located at the axial rear end of the annular wall, and the end wall is fixed to the motor shaft.

[0014] A further improved solution is: the outer rotor assembly includes a plurality of magnets attached to the inner wall of the annular wall, the magnets are located radially outside the inner stator core, and the magnets are arranged around the inner stator core.

[0015] A further improvement is as follows: the outer rotor motor comprises a fan housing sleeved on the outer periphery of the outer rotor assembly, the fan housing is located at the axial rear end of the base, and the fan housing is fixedly connected to the base.

[0016] Compared with the prior art, the utility model has the following beneficial effects: the inner stator assembly includes a connector located between the inner peripheral wall of the inner stator core and the outer surface of the support portion, and the connector is integrally formed between the support portion and the inner stator core by a mass-molded plastic. In this way, the connector separates the support portion and the inner stator core, so that an insulating structure is formed between the two, and the connector can ensure the matching strength between the two; at the same time, there is no need to fine-process the support portion, which can simplify the process and reduce costs. [Drawings]

[0017] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings:

[0018] Figure 1 It is a three-dimensional schematic diagram of the outer rotor motor of the utility model;

[0019] Figure 2 yes Figure 1 A cross-sectional view of an outer rotor motor is shown;

[0020] Figure 3 yes Figure 2 An exploded view of an external rotor motor is shown;

[0021] Figure 4 yes Figure 3 A three-dimensional schematic diagram of an inner stator assembly of an outer rotor motor shown;

[0022] Figure 5 yes Figure 4 The three-dimensional schematic diagram of the inner stator bracket and insulating gasket of the outer rotor motor shown.

[0023] Meaning of the reference numerals in the figures:

[0024] External rotor motor 100 Motor shaft 1

[0025] Front bearing 10 Rear bearing 11

[0026] Outer rotor assembly 2 Outer rotor housing 20

[0027] Annular wall 201 End wall 202

[0028] Ventilation 203 Magnetic steel frame 21

[0029] Magnetic steel 22 Inner stator assembly 3

[0030] Inner stator bracket 30 base 301

[0031] Support portion 302 First coupling portion 303

[0032] Connecting member 31 Second connecting portion 311

[0033] Insulation gasket 32 ​​Inner stator core 33

[0034] Coil winding 34 Fan cover housing 4 [Specific implementation method]

[0035] 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.

[0036] See also Figures 1 to 5 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.

[0037] See also Figures 2 to 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.

[0038] 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.

[0039] 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.

[0040] See also Figures 3 to 5As 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 33 fixed to the inner stator bracket 30, a connector 31 located between the inner stator core 33 and the inner stator bracket 30, and a plurality of coil windings 34 wound on the inner stator core 33. The inner stator core 33 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 33, and the inner stator plastic package can separate different teeth and play an insulating role. The coil winding 34 is wound on the tooth portion of the inner stator core 33 through the inner stator plastic package, and the coil winding 34 is arranged corresponding to the tooth portion. The coil winding 34 can be a plurality of groups, and the coil winding 34 can generate electromagnetic induction when powered on.

[0041] When winding the coil winding 34, a winding machine can be used to independently wind each inner stator core 33 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.

[0042] Further, 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.

[0043] The inner stator support 30 includes a base 301 located at the axial front end of the inner stator core 33 and a support portion 302 extending axially backward from the base 301 . The inner stator core 33 is sleeved on the outer periphery of the support portion 302 .

[0044] Further, the inner stator assembly 3 includes a connector 31 located between the inner peripheral wall of the inner stator core 33 and the outer surface of the support portion 302 and an insulating gasket 32 ​​sleeved on the outer periphery of the support portion 302, the connector 31 is integrally formed between the support portion 302 and the inner stator core 33 by a mass-molded plastic, the insulating gasket 32 ​​is located between the base 301 and the inner stator core 33 in the front-to-back direction, and the insulating gasket 32 ​​is made of insulating material, such as plastic, rubber, etc. The insulating gasket 32 ​​forms an insulation isolation between the axial front end of the inner stator core 33 and the axial rear end of the base 301, thereby improving the safety of the outer rotor motor 100.

[0045] The size and shape of the inner periphery of the insulating gasket 32 ​​match the size and shape of the outer periphery of the supporting portion 302, and the size and shape of the outer periphery of the insulating gasket 32 ​​match the size and shape of the inner periphery of the inner stator core 33; the thickness of the insulating gasket 32 ​​is not less than 2 mm;

[0046] After the winding of the inner stator core 33 is completed, the inner stator core 33 and the inner stator bracket 30 are placed in a jig and fixed by a tooling, and then the mass molding plastic is injected forward from the axial rear end of the inner stator core 33 into the gap between the support part 302 and the inner stator core 33 to form the connecting member 31. The connecting member 31 can firmly fix the inner stator core 33 on the support part 302, and the inner stator core 33 will not have axial movement and radial sliding.

[0047] The connector 31 can form an insulating structure between the inner stator core 33 and the support portion 302 and ensure the matching strength between the two, so that the outer rotor motor 100 can operate more reliably; at the same time, there is no need to fine-process the support portion 302, which can reduce the number of processes and save costs.

[0048] The outer periphery of the support portion 302 includes a first joint portion 303, and the inner periphery of the connector 31 includes a second joint portion 311. The second joint portion 311 is mounted to the first joint portion 303 in cooperation. The shapes of the first joint portion 303 and the second joint portion 311 are adapted to each other. One of the first joint portion 303 and the second joint portion 311 is set as a protrusion, and the other is set as a depression. In this embodiment, the first joint portion 303 is set as a depression, and the second joint portion 311 is set as a protrusion; it can be imagined that in other embodiments, the first joint portion 303 is set as a protrusion, and the second joint portion 311 is set as a depression. The first joint portion 303 and the second joint portion 311 are set to further limit the inner stator core 33 in radial direction, so that the inner stator core 33 will not move radially.

[0049] The outer rotor assembly 2 includes a magnetic steel frame 21 located in the outer rotor housing 20 and a plurality of magnetic steels 22 mounted on the magnetic steel frame 21. The outer diameter of the magnetic steel frame 21 is adapted to the inner diameter of the outer rotor housing 20. The magnetic steel frame 21 is attached to the inner wall of the annular wall 201. The magnetic steels 22 are evenly placed in the gaps of the magnetic steel frame 21 along the circumferential direction and attached to the inner wall of the annular wall 201. The magnetic steels 22 are located at the radial outer periphery of the inner stator core 33. The magnetic steels 22 cooperate with the inner stator assembly 3 through electromagnetic induction to convert electrical energy into mechanical energy, so that the magnetic steels 22 rotate themselves and drive the outer rotor housing 20 to rotate, and further drive the motor shaft 1 to rotate.

[0050] Furthermore, the shape of the magnetic steel 22 is a tile shape, and the magnetic steel 22 can be attached to the inner wall of the annular wall 201 by using a colloid; the magnetic steel 22 is one of an aluminum nickel cobalt magnetic steel, a ferrite magnetic steel and a neodymium iron boron magnetic steel. Of course, the type of the magnetic steel 22 is not limited to the three types mentioned above, and technical personnel in this field 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.

[0051] The outer rotor motor 100 includes a fan housing 4 sleeved on the outer periphery of the outer rotor assembly 2 . The fan housing 4 is located at the axial rear end of the base 301 . The fan housing 4 is fixedly connected to the base 301 .

[0052] The outer rotor motor 100 is provided with a front bearing 10 and a rear bearing 11 located at the 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 axial rear end of the fan housing 4, and the motor shaft 1 is supported in the fan housing 4 through the rear bearing 11.

[0053] In this embodiment, the inner stator assembly 3 includes the connector 31 located between the inner peripheral wall of the inner stator core 33 and the outer surface of the support portion 302, and the connector 31 is integrally formed of a mass-molded plastic between the support portion 302 and the inner stator core 33. In this way, the connector 31 separates the support portion 302 and the inner stator core 33, so that an insulating structure is formed between the two, and the connector 31 can ensure the matching strength between the two; at the same time, there is no need to perform fine processing on the support portion 302, which can simplify the process and reduce costs.

[0054] 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 holding the motor shaft, and an inner stator assembly located between the motor shaft and the outer rotor assembly, wherein 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, wherein the inner stator bracket comprises a base located at the axial front end of the inner stator core and a support portion extending axially backward from the base, wherein the inner stator core is sleeved on the outer periphery of the support portion; characterized in that: The inner stator assembly comprises a connecting piece located between the inner peripheral wall of the inner stator core and the outer surface of the support portion, and the connecting piece is integrally formed between the support portion and the inner stator core by mass molding plastic.

2. The outer rotor motor according to claim 1, characterized in that: The outer periphery of the supporting portion includes a first coupling portion, the inner periphery of the connecting member includes a second coupling portion, and the second coupling portion is fitted to the first coupling portion.

3. The outer rotor motor according to claim 2, characterized in that: The shapes of the first combining portion and the second combining portion are adapted to each other, and one of the first combining portion and the second combining portion is configured as a convexity, and the other is configured as a concaveity.

4. The outer rotor motor according to claim 3, characterized in that: The inner surface of the connecting member is attached to the outer surface of the supporting portion, and the inner peripheral wall of the inner stator core is attached to the outer surface of the connecting member.

5. The outer rotor motor according to claim 4, characterized in that: The inner stator assembly includes an insulating gasket sleeved on the outer periphery of the support portion, and the insulating gasket is located between the base and the inner stator core in the front-to-back direction.

6. The outer rotor motor according to claim 5, characterized in that: The size and shape of the inner periphery of the insulating gasket are matched with the size and shape of the outer periphery of the supporting portion; the size and shape of the outer periphery of the insulating gasket are matched with the size and shape of the inner periphery of the inner stator core.

7. The outer rotor motor according to claim 6, characterized in that: The thickness of the insulating gasket is not less than 2 mm.

8. The outer rotor motor according to claim 1, characterized in that: The outer rotor assembly includes an outer rotor housing for accommodating the inner stator assembly. The outer rotor housing is provided with an annular wall sleeved on the outer periphery of the inner stator core and an end wall located at the axial rear end of the annular wall. The end wall is fixed to the motor shaft.

9. The outer rotor motor according to claim 8, characterized in that: The outer rotor assembly includes a plurality of magnetic steels attached to the inner wall of the annular wall. The magnetic steels are located radially outside the inner stator core and are arranged around the inner stator core.

10. The outer rotor motor according to claim 9, characterized in that: The outer rotor motor comprises a fan housing sleeved on the outer periphery of the outer rotor assembly, the fan housing is located at the axial rear end of the base, and the fan housing is fixedly connected to the base.

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