External rotor motor

Abstract

An outer rotor motor comprises a motor shaft, an outer rotor assembly fixedly holding the motor shaft and an inner stator assembly located between the motor shaft and the outer rotor assembly, and the inner stator assembly comprises an inner stator support arranged on the periphery of the motor shaft in a sleeving mode 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 main body part is arranged on the periphery of the motor shaft in a sleeving mode; the base comprises a supporting part extending backwards from a main body part in the axial direction, the inner stator assembly comprises an annular sleeve fixedly arranged on the outer circumferential face of the supporting part, and the inner circumferential wall of the inner stator iron core is fixedly arranged on the outer surface of the annular sleeve. As the annular sleeve and the inner stator iron core are made of the same material, the material performance of the annular sleeve and the inner stator iron core is similar, no cutting waste is generated when the inner stator iron core is pressed on the annular sleeve, meanwhile, the stable binding force between the annular sleeve and the inner stator iron core can reduce and even avoid the possibility of relative sliding, and the safety of the outer rotor motor in the operation process is ensured.

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 bracket. [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 use brackets inserted into the stator core. As a structural connection between the motor and the whole machine, the bracket must ensure a certain strength. It is basically made of aluminum alloy. The aluminum alloy bracket and the steel stator core are interference fit to ensure that the bonding force between the two meets the working conditions of the motor; however, due to the difference in material properties between steel and aluminum, the interference fit between the two will cause the aluminum to be cut when pressed in, thereby generating aluminum chips, which will accumulate in the chip storage groove on the aluminum alloy bracket.

[0003] When too much aluminum chips are generated, the aluminum chips in the chip storage groove will cause the stator core to be squeezed and deformed, so that the aluminum chips are discharged from the chip storage groove and fall into the inner part of the outer rotor motor, causing the insulation and withstand voltage performance of the outer rotor motor to deteriorate and generate noise. In order to avoid the generation of aluminum chips, a refrigerated aluminum alloy bracket can be used to press the stator core, but the current market uses a liquid helium rapid cooling process to refrigerate the aluminum alloy bracket, which has certain safety risks and is expensive.

[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 of the prior art, the purpose of the utility model is to provide an outer rotor motor, wherein no aluminum chips are generated during the assembly of an inner stator bracket and an inner stator core of the outer rotor motor.

[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 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; 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, wherein the main body is sleeved on the outer periphery of the motor shaft; the base comprises a supporting portion extending axially backward from the main body, the inner stator assembly comprises an annular sleeve fixed on the outer peripheral surface of the supporting portion, and the inner peripheral wall of the inner stator core is fixed on the outer surface of the annular sleeve.

[0007] A further improvement is that the hardness of the support portion is smaller than the hardness of the annular sleeve, the outer diameter of the support portion is larger than the inner diameter of the annular sleeve, and the inner circumference of the annular sleeve is fitted to the outer circumference of the support portion.

[0008] A further improved solution is that the hardness of the outer surface of the annular sleeve that contacts the inner peripheral wall of the inner stator core is greater than the hardness of the supporting portion.

[0009] A further improvement is that the material of the inner stator core is the same as that of the annular sleeve, and both are made of steel.

[0010] A further improved solution is: the outer diameter of the annular sleeve is larger than the inner diameter of the inner stator core, and the inner stator core is fixed to the outer peripheral surface of the annular sleeve in an interference fit manner.

[0011] A further improvement is as follows: the axial length of the support portion and the annular sleeve is not greater than the axial length of the inner stator core; a step portion is provided at the connection between the main body portion and the support portion, and the end of the annular sleeve abuts against the step portion.

[0012] A further improved solution is: the inner stator assembly includes an inner stator plastic cover sleeved on the inner stator core and a plurality of windings wound on the inner stator plastic cover.

[0013] A further improvement is as follows: the outer rotor assembly includes an outer rotor casing for accommodating the inner stator assembly, the outer rotor casing 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 on 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 scheme is: the outer rotor motor includes a front bearing accommodated in the axial front end of the base and a rear bearing accommodated in the axial rear end of the inner stator core, the motor shaft is supported in the inner stator bracket through the front bearing, the outer peripheral surface of the rear bearing is attached to the inner peripheral wall of the inner stator core, and the motor shaft is supported at the axial rear end of the inner stator core through the rear bearing.

[0016] Compared with the prior art, the utility model has the following beneficial effects: the base includes a support portion extending axially backward from the main body, the inner stator assembly includes an annular sleeve fixed to the outer peripheral surface of the support portion, and the inner peripheral wall of the inner stator core is fixed to the outer surface of the annular sleeve. Since the annular sleeve and the inner stator core are made of the same material, the material properties of the two are similar, so when the inner stator core is pressed onto the annular sleeve, no cutting waste is generated, and at the same time, the stable bonding force between the two can greatly reduce or even avoid the possibility of relative sliding, thereby ensuring the safety of the outer rotor motor during operation. [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 outer rotor motor is shown;

[0021] Figure 4 yes Figure 1 A three-dimensional schematic diagram of an inner stator assembly of an outer rotor motor shown;

[0022] Figure 5 yes Figure 1 A three-dimensional schematic diagram of an inner stator bracket of an outer rotor motor shown;

[0023] Figure 6 yes Figure 5 A cross-sectional view of an inner stator support of an outer rotor motor shown;

[0024] Figure 7 yes Figure 1 A three-dimensional schematic diagram of an outer rotor housing of an outer rotor motor shown;

[0025] Figure 8 yes Figure 7 A three-dimensional schematic diagram of the outer rotor housing of the outer rotor motor shown in another angle;

[0026] Fig. 9 yes Figure 8 A cross-sectional view of an outer rotor housing and magnetic steel of an outer rotor motor shown;

[0027] Fig.10 yes Figure 1 A three-dimensional schematic diagram of an outer rotor housing of an outer rotor motor shown;

[0028] Fig.11 yes Fig.10 A three-dimensional schematic diagram of the outer rotor housing of the outer rotor motor shown in another angle;

[0029] Fig.12 yes Figure 1 A cross-sectional view of the outer rotor housing and fan of the outer rotor motor shown;

[0030] Fig.13 yes Figure 1 A three-dimensional schematic diagram of an insulating gasket of an outer rotor motor shown;

[0031] Fig.14 yes Figure 1 A three-dimensional schematic diagram of the motor shaft of the external rotor motor shown.

[0032] Meaning of the reference numerals in the figures:

[0033] External rotor motor 100 Motor shaft 1

[0034] Front bearing 10 Spacer 101

[0035] Circlip 102 Rear bearing 11

[0036] First joint 12 Outer rotor assembly 2

[0037] Outer rotor housing 20 annular wall 201

[0038] Magnetic steel slot 2010 Receiving slot 2011

[0039] End wall 202 Air inlet 2020

[0040] The first extension portion 203 and the second extension portion 204

[0041] Second combining portion 2040 First matching portion 2041

[0042] Extension 205 Inner stator assembly 3

[0043] Inner stator bracket 30 base 301

[0044] Main body part 302 Support part 303

[0045] Step 304 Annular sleeve 31

[0046] Insulation gasket 32 ​​outer ring 321

[0047] Inner ring 322 Boss 323

[0048] Inner stator core 33 Winding 34

[0049] Fan 4 Second matching portion 40

[0050] Radial width D1 of magnetic steel slot Radial width D2 of receiving slot

[0051] Radial depth of magnetic steel groove D3 Radial depth of receiving groove D4 [Specific implementation method]

[0052] 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.

[0053] See also Figures 1 to 14 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.

[0054] See also Figures 1 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 arranged through the end wall 202.

[0055] The outer rotor housing 20 may be cylindrical, and its outer 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; it can be understood that in other alternative embodiments, the outer rotor housing 20 may be made of other materials.

[0056] Please combine Fig. 9As shown, the outer rotor housing 20 also includes an extension portion 205 protruding from the end wall 202 to both axial ends, and the extension portion 205 includes a first extension portion 203 located at the axial front end of the end wall 202 and a second extension portion 204 located at the axial rear end of the end wall 202.

[0057] The annular wall 201, the end wall 202, the first extension portion 203 and the second extension portion 204 are integrally formed by a cold heading process. After the outer rotor housing 20 is formed by cold heading, each part can be processed by a finishing method, for example: the axial length, wall thickness, etc. of the first extension portion 203 and the second extension portion 204 can be changed by cutting.

[0058] In the conventional solution, the outer rotor housing 20 is integrally formed by a stamping process. Due to the characteristics of the stamping part itself, on the one hand, the wall thickness of the end wall 202 and the first extension portion 203 are the same; on the other hand, the stamping process cannot form the first extension portion 203 and the second extension portion 204 at the axial ends of the end wall 202, respectively, and usually only the first extension portion 203 located at the axial front end of the end wall 202 is formed. After the motor shaft 1 is matched with the end wall 202 and the first extension portion 203 and installed, during the use of the outer rotor motor 100, the joint between the motor shaft 1 and the outer rotor housing 20 may be broken, causing the outer rotor motor 100 to fail and be damaged.

[0059] In this embodiment, when the outer rotor housing 20 is cold-forged, the first extension portion 203 and the second extension portion 204 are integrally formed at both axial ends of the end wall 202. After the motor shaft 1 is matched with the first extension portion 203, the end wall 202 and the second extension portion 204 and installed, the bonding force at the matching point between the motor shaft 1 and the outer rotor housing 20 and the dimensional accuracy after pressing can be improved, and the strength of the outer rotor housing 20 during rotation can be improved.

[0060] See also Figure 3 As shown, the outer diameter of the motor shaft 1 is greater than the inner diameter of the first extension portion 203 , and the outer circumference of the motor shaft 1 is installed on the inner circumference of the first extension portion 203 by interference fit.

[0061] Furthermore, please combine Figure 7 and Fig.14As shown, the inner wall of the second extension portion 204 includes a plurality of second combining portions 2040, and the axial rear end of the motor shaft 1 includes a plurality of first combining portions 12, the first combining portions 12 and the second combining portions 2040 are the same in number and have matching shapes, the outer circumferential surface of the first combining portion 12 is fitted on the inner circumferential surface of the second combining portion 2040, the outer diameter of the first combining portion 12 is greater than the inner diameter of the second combining portion 2040, and the motor shaft 1 is fitted in the second combining portion 2040 of the second extension portion 204 by means of a small interference fit or overfit of the first combining portion 12.

[0062] The first combination part 12 and the second combination part 2040 are provided to further increase the combination force between the motor shaft 1 and the outer rotor housing 20, so that relative sliding between the motor shaft 1 and the outer rotor housing 20 is prevented during the operation of the outer rotor motor 100. In this embodiment, the first combination part 12 is set as a protrusion, and the second combination part 2040 is set as a depression; alternatively, the first combination part 12 can also be set as a depression, and the second combination part 2040 can be set as a protrusion; the shapes of the first combination part 12 and the second combination part 2040 can be selected according to needs, such as: the shape of the protrusion is set as a trapezoid, a semi-cylindrical shape, a triangle, etc. Preferably, the number of the first combination part 12 and the second combination part 2040 is at least 3, and such a setting can reduce the possibility of relative sliding between the two.

[0063] Providing a chamfer at the junction of the first extension portion 203 and the end wall 202 can further improve the strength of the outer rotor housing 20 and reduce the possibility of fracture between the first extension portion 203 and the end wall 202 .

[0064] Since the outer rotor housing 20 is integrally formed by a cold heading process, the sizes of the first extension portion 203 and the second extension portion 204 can be freely selected by fine machining, so the wall thickness of the first extension portion 203 and the second extension portion 204 can be made greater than the wall thickness of the end wall 202, which can further improve the strength of the outer rotor housing 20. Preferably, the wall thickness of the second extension portion 204 is not less than 2 mm, so that the second extension portion 204 and the end wall 202 have good strength, and the second extension portion 204 will not be fractured and failed.

[0065] See also Figure 7 , Fig. 9 and Fig.12As shown, the outer rotor housing 20 is fixed with a fan 4, and the fan 4 is integrally injection molded onto the outer rotor housing 20. Specifically, after the outer rotor housing 20 is finely machined, the fan 4 is integrally injection molded onto the second extension portion 204. The fan 4 rotates together with the outer rotor housing 20.

[0066] In the traditional solution, the fan 4 is fixed to the axial rear end of the motor shaft 1, and the two are assembled by interference fit. At the same time, in order to reduce the possibility of sliding between the fan 4 and the motor shaft 1, it is necessary to add knurling to the outer circumferential surface of the motor shaft 1 or to add an insert to the center hole of the inner ring of the fan 4 when injection molding. This assembly method has many parts and complex processes.

[0067] In this embodiment, after the outer rotor housing 20 is cold-forged, it is placed in a jig, and the fan 4 is directly molded on the second extension portion 204 by injection molding, which can reduce production processes and improve production efficiency, and the integral molding can improve the balance between the fan 4 and the second extension portion 204. The fan 4 can be injection molded by plastic materials, or other metal materials such as aluminum.

[0068] Furthermore, a first matching portion 2041 is formed on the outer periphery of the second extending portion 204, and a second matching portion 40 is formed on the inner periphery of the fan 4. The second matching portion 40 is matched with the first matching portion 2041 in shape, and the two are fitted together.

[0069] In this embodiment, the first matching portion 2041 is configured as an annular groove, and the second matching portion 40 is configured as an annular protrusion. The two match each other so that the fan 4 will not move axially or fall off due to vibration during rotation.

[0070] Considering that the second extension portion 204 needs to be provided with the first matching portion 2040 and the fan 4 needs to be injection molded, the axial length of the second extension portion 204 is not less than 4 mm, the thickness of the fan 4 can be selected according to design requirements, the axial rear end face of the fan 4 can protrude out of the axial rear end face of the second extension portion 204, or the axial rear end face of the fan 4 is flush with the axial rear end face of the second extension portion 204, or the axial rear end face of the fan 4 is shorter than the axial rear end face of the second extension portion 204.

[0071] In order to ensure the binding force between the first matching portion 2041 and the second matching portion 40, the axial length of the first matching portion 2041 is not less than 2 mm, and the radial depth of the first matching portion 2041 is not less than 1 mm. When the axial length and radial depth of the first matching portion 2041 are too small, the axial positioning effect on the fan 4 is poor, and the fan 4 may move axially on the second extension portion 204 or even fall off.

[0072] Please combine Figure 8 As shown, the end wall 202 is provided with a plurality of air outlets 2020 penetrating the end wall 202, the air outlets 2020 are located at the axial front end of the fan 4, and the fan 4 is arranged adjacent to the air outlets 2020. In this embodiment, the fan 4 is a centrifugal fan, and the fan blades of the fan 4 are arranged toward the air outlets 2020. The fan 4 can inhale external air from the axial front end of the outer rotor motor 100 and discharge it from the axial rear end, so as to achieve the purpose of cooling the outer rotor motor 100.

[0073] The air outlet 2020 is used to discharge the cooling air entering the outer rotor motor 100. When the outer rotor motor 100 is started, the outer rotor housing 20 rotates and drives the fan 4 to rotate. Due to the characteristics of the centrifugal fan, external air enters from the axial front end of the outer rotor motor 100. After the external air flows through the inner stator assembly 3, the inner stator assembly 3 is cooled and dissipated, and then discharged from the air outlet 2020.

[0074] In this embodiment, the number of the air outlets 2020 is 6, which are circular in shape and arranged around the center of the end wall 202, which not only ensures the air volume of cooling air but also makes the shape beautiful; preferably, the number of the air outlets 2020 can be one or more, and the shape can be any shape or a combination of different shapes.

[0075] The fan 4 does not need to be assembled by press-fitting, so the length of the fan 4 from the end wall 202 can be selected according to design requirements. Preferably, the fan 4 is fitted to the end surface of the end wall 202, which can increase the amount of cooling air entering the outer rotor motor 100 and achieve better heat dissipation effect. At the same time, it can also reduce the axial size, making the outer rotor motor 100 compact.

[0076] In another embodiment, the fan 4 is integrally injection molded on the first extension portion 203, and the first matching portion 2041 is provided on the first extension portion 203 to prevent the fan 4 from axially moving on the first extension portion 203. At this time, in order to cool the outer rotor motor 100, the fan 4 needs to be an axial flow fan.

[0077] See also Figures 4 to 5 As 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 on the inner stator bracket 30, and a plurality of 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 overmolding (not shown) is arranged between the tooth slots (not shown) of the inner stator core 33, and the inner stator overmolding can separate different teeth and play an insulating role. The winding 34 is wound on the tooth portion of the inner stator core 33 through the inner stator overmolding, and the winding 34 is arranged corresponding to the tooth portion. The winding 34 can be multiple groups, and the winding 34 can generate electromagnetic induction when powered on.

[0078] When winding the winding 34, a winding machine can be used to independently wind each 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.

[0079] 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 second extension portion 204 and is rotatably connected to the outer rotor housing 20.

[0080] The inner stator bracket 30 includes a base 301 located at the axial front end of the inner stator core 33, 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.

[0081] The outer periphery of the support portion 303 is provided with an annular sleeve 31, and the inner peripheral wall of the inner stator core 33 is mounted on the outer peripheral surface of the annular sleeve 31. The material of the annular sleeve 31 is the same as that of the inner stator core 33. Specifically, the annular sleeve 31 is made of steel, and the hardness of the annular sleeve 31 is greater than the hardness of the support portion 303.

[0082] In this embodiment, after the inner stator bracket 30 is roughly machined, the annular sleeve 31 is pressed onto the outer periphery of the support portion 303. The outer diameter of the support portion 303 is larger than the inner diameter of the annular sleeve 31. Due to the difference in materials between the two, during the press-fitting process, the annular sleeve 31 will cut the support portion 303 and generate aluminum chips, which can be removed after the press-fitting. At the same time, the inner stator bracket 30 after the annular sleeve 31 is pressed is finely machined to obtain the required design dimensions and meet the accuracy requirements to the greatest extent.

[0083] In the traditional assembly scheme, the inner peripheral wall of the inner stator core 33 is directly matched with the outer peripheral surface of the support part 303 for installation. The inner diameter of the inner stator core 33 is smaller than the outer diameter of the support part 303. During the installation process, the steel inner stator core 33 will cut the outer peripheral surface of the aluminum support part 303, thereby generating aluminum chips and falling into the interior of the outer rotor motor 100. The aluminum chips will affect the outer rotor motor 100 and other parts inside it, and even cause failure. An existing improvement scheme is: a chip storage groove is provided on the outer peripheral surface of the support part 303. At this time, the aluminum chips generated by cutting will accumulate in the chip storage groove. However, when there are too many aluminum chips, the steel sheet of the stator core 33 will be squeezed and deformed, and the aluminum chips will fall out from the press-fit stop surface of the inner stator bracket 30 into the interior of the outer rotor motor 100, which will cause the problem of poor insulation withstand voltage, increased noise, or even failure. Another improvement scheme is to refrigerate the inner stator bracket 30 before press-fitting, which can avoid the generation of cutting aluminum chips. However, the refrigeration process currently on the market uses liquid helium rapid cooling. Using this scheme has certain safety risks and is too costly.

[0084] In this embodiment, after the annular sleeve 303 is sleeved on the outer periphery of the support portion 303, the inner stator core 33 is press-fitted onto the annular sleeve 31. The inner diameter of the inner stator core 33 is smaller than the outer diameter of the annular sleeve 31. The inner stator core 33 is installed onto the annular sleeve 31 by interference fit, which can ensure a high bonding force between the two. Since the annular sleeve 31 and the inner stator core 33 are made of the same material, the material properties of the two are similar, such as steel is used for manufacturing and forming, so no cutting waste is generated when the two are press-fitted. At the same time, the stable bonding force between the two can greatly reduce or even avoid the possibility of relative sliding, ensuring the safety of the outer rotor motor 100 during operation.

[0085] Optionally, the annular sleeve 31 can be manufactured and formed from a variety of materials. The outer circumferential wall of the annular sleeve 31 that contacts the inner circumferential wall of the inner stator core 33 is manufactured and formed from steel; the inner circumferential wall of the annular sleeve 31 that contacts the outer circumferential wall of the support portion 303 is manufactured and formed from other materials, such as plastic, metal, etc.

[0086] The axial length of the annular sleeve 31 is not greater than the axial length of the inner stator core 33 , and the combined portion of the two needs to maintain a certain matching length to meet the matching force requirements of the two.

[0087] A step portion 304 is provided at the connection between the main body portion 302 and the support portion 303 . The end of the annular sleeve 31 abuts against the step portion 304 . The step portion 304 can provide axial positioning when the annular sleeve 31 is press-fitted onto the support portion 303 .

[0088] After the inner stator core 33 is pressed into the inner stator bracket 30, when the winding slot full rate of the inner stator core 33 is high, the lead wire and the bridge wire on the winding 34 will be close to or even fit the inner stator bracket 30 in the axial direction. Although the outer layer of the enameled wire of the winding 34 has a layer of insulating varnish, the insulating varnish may be scratched. At this time, when the damaged enameled wire contacts the metal inner stator bracket 30, the outer rotor motor 100 will have poor insulation withstand voltage or even fail.

[0089] Please combine Figure 4 , Figure 6 and Fig.13 As shown, the inner stator assembly 3 includes an insulating gasket 32 ​​sleeved on the outer periphery of the main body 302, and the insulating gasket 32 ​​is located between the inner stator core 33 and the base 301. Preferably, the insulating gasket 32 ​​is arranged adjacent to the base 301, and the insulating gasket 32 ​​can be attached to the end surface of the base 301. The insulating gasket 32 ​​is made of an insulating material, and the insulating gasket 32 ​​can separate the enameled wire of the winding 34 from the inner stator bracket 30 in the axial direction to prevent the enameled wire from making electrical contact with the inner stator bracket 30.

[0090] Furthermore, the insulating gasket 32 ​​is in a circular ring shape, and includes an outer ring 321 located on the outside, an inner ring 322 located on the inside, and a plurality of bosses 323 located on the inner ring 322, and the bosses 323 may be in a semicircular shape, a semi-trapezoidal shape, etc. The diameter of the inner ring 322 is larger than the outer diameter of the main body 302, and the inner diameter of the bosses 323 is smaller than the outer diameter of the main body 302. The insulating gasket 32 ​​is clamped on the outer periphery of the main body 302 through the bosses 323, and the inner ring 322 does not contact the main body 302.

[0091] The insulating gasket 32 ​​is made of soft material and has a certain resilience. Therefore, when the insulating gasket 32 ​​is clamped on the main body 302 by the boss 323, it can be ensured that there is a certain bonding force between the two and the insulating gasket 32 ​​will not produce excessive deformation.

[0092] The thickness of the insulating gasket 32 ​​can be selected according to the design requirements, such as: selecting a suitable size according to the distance between the inner stator core 33 and the inner stator bracket 30 after the inner stator core 33 is installed; optionally, the thickness of the insulating gasket 32 ​​is 0.1mm to 2mm; in addition, when the outer rotor motor 100 is a high-voltage motor, the thickness of the insulating gasket 32 ​​needs to be increased accordingly. After the inner stator core 33 is assembled, the end face of its axial front end is approximately 5mm to 20mm away from the insulating gasket 32. The enameled wire of the winding 34 may approach or touch the insulating gasket 32. At this time, the insulating gasket 32 ​​made of insulating material can achieve axial insulation between the winding 34 and the inner stator bracket 30, thereby improving the insulation performance of the outer rotor motor 100 and making it safer and more reliable to use.

[0093] See also Figures 9 to 11 As shown, the outer rotor assembly 2 includes a plurality of magnets 21 attached to the inner wall of the outer rotor housing 20, the magnets 21 are arranged around the inner stator core 33, and the outer rotor housing 20 also includes a plurality of magnet slots 2010 recessed on the inner wall of the annular wall 201, and each of the magnets 21 is accommodated in the magnet slot 2010. The magnets 21 cooperate with the inner stator assembly 3 through electromagnetic induction to convert electrical energy into mechanical energy, so that the magnets 21 rotate themselves and drive the outer rotor housing 20 to rotate, and further drive the motor shaft 1 to rotate.

[0094] Furthermore, the magnetic steel 21 is one of AlNiCo magnetic steel, ferrite magnetic steel and NdFeB magnetic steel. Of course, the type of the magnetic steel 21 is not limited to the three types mentioned above, and those skilled in the art can also select other types of the magnetic steel 21 according to actual conditions and needs.

[0095] The number of the magnetic steels 21 is consistent with that of the magnetic steel slots 2010 and their shapes are adapted; in the present embodiment, the shape of the magnetic steel 21 is a square, and the square-shaped magnetic steel 21 can make the outer rotor motor 100 more smoothly controlled, and the square shape is more conducive to processing; optionally, the magnetic steel 21 can be any shape such as a tile shape, an arc shape, etc.; the number of the magnetic steels 21 is selected according to the design requirements of the outer rotor motor 100, for example, it can be 6, 8, 12, or even less or more.

[0096] In the traditional assembly scheme, a plastic bracket needs to be placed inside the outer rotor housing 20. Specifically, the plastic bracket is attached to the inner wall of the annular wall 201. The plastic bracket is provided with grooves spaced apart from each other. After the plastic bracket is placed at the bottom of the outer rotor housing 20, the magnetic steel 21 is inserted into the groove of the plastic bracket, and the back of the magnetic steel 21 is brushed with glue to ensure that the magnetic steel 21 can be more firmly attached to the inner wall of the annular wall 201. However, the positioning of the magnetic steel 21 by the plastic bracket in this scheme is not reliable enough, and since the plastic bracket needs to be placed in the outer rotor housing 20 first, the installation process is complicated and the efficiency is low.

[0097] In this embodiment, after the outer rotor housing 20 is cold-forged, the magnetic steel groove 2010 is formed on the inner wall of the annular wall 201 by fine machining, and no additional plastic bracket is required, and the magnetic steel 21 can be directly placed in the magnetic steel groove 2010. Since the shape of the magnetic steel groove 2010 is compatible with the shape of the magnetic steel 21, after the magnetic steel 21 is placed in the magnetic steel groove 2010, at least part of the inner wall of the magnetic steel groove 2010 abuts against the outer wall of the magnetic steel 21, which can provide better positioning for the magnetic steel 21. After installation, it can be more firmly fixed to the inner wall of the magnetic steel groove 2010. This solution can reduce the process flow, improve assembly efficiency, reduce production costs, and make the magnetic steel 21 more reliably fixed in the outer rotor housing 20.

[0098] Furthermore, in order to improve the fixing effect of the magnetic steel 21, it is necessary to use a glue-like substance to bond and fix the magnetic steel 21. The glue-like substance can be glue, etc. The glue can more firmly attach the magnetic steel 21 to the magnetic steel slot 2010. When the magnetic steel 21 is coated with glue and placed in the magnetic steel slot 2010, part of the glue will leak from the outer peripheral wall of the magnetic steel slot 2010, and the magnetic steel 21 will partially protrude from the magnetic steel slot 2010 in the radial direction, which will affect the operation of the outer rotor motor 100.

[0099] To this end, each of the annular walls 201 is provided with a receiving groove 2011 that is radially recessed from the bottom of the magnetic steel groove 2010, and the receiving groove 2011 is located radially outside the magnetic steel groove 2010; after the outer rotor housing 20 is cold-forged, the magnetic steel groove 2010 and the receiving groove 2011 are processed and formed on the inner wall of the annular wall 201. After one side of the magnetic steel 21 is coated with glue and placed in the magnetic steel groove 2010, part of the glue will flow into the receiving groove 2011, so that the glue will not flow out from the periphery of the magnetic steel groove 2010, thereby not affecting the operation of the outer rotor motor 100.

[0100] Specifically, the axial length of the receiving groove 2011 is not greater than the axial length of the magnetic steel groove 2010, the radial width D2 of the receiving groove 2011 is not less than 60% of the radial width D1 of the magnetic steel groove 2010, the wall thickness of the annular wall 201 is at least 1.5 mm greater than the radial depth D3 of the magnetic steel groove 2010, and the radial depth D4 of the receiving groove is 0.1 mm to 0.5 mm. The shape and size of the magnetic steel groove 2010 are adapted to the magnetic steel 21, so that the magnetic steel 21 can be better fixed on the annular wall 201, the receiving groove 2011 can accommodate the glue on the magnetic steel 21, so that the glue will not overflow from the side of the magnetic steel groove 2010, and the size design of the magnetic steel groove 2010 and the receiving groove 2011 can make the annular wall 201 have sufficient strength.

[0101] See also Figure 3 and Figure 4 As shown, 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 located at the axial rear end of the inner stator core 33, and further, the rear bearing 11 is located in the through hole of the inner stator core 33, so that the motor shaft 1 is supported in the inner stator core 33 through the rear bearing 11.

[0102] The radial dimension of the front bearing 10 may be greater than the radial dimension of the rear bearing 11, and the outer diameter dimension of the rear bearing 11 may be matched with the inner diameter dimension of the inner stator core 33. By arranging the rear bearing 11 in the inner stator core 33, the mold opening cost of the bearing chamber for installing the rear bearing 11 can be saved, thereby simplifying the process and saving production costs.

[0103] Furthermore, the outer rotor motor 100 further includes a retaining spring 102 disposed at the axial front end of the motor shaft 1, the retaining spring 102 can be clamped on the motor shaft 1, and the retaining spring 102 is located on a section of the motor shaft 1 that passes through the inner stator bracket 30. Specifically, the retaining spring 102 is disposed close to the front bearing 10 to prevent the front bearing 10 from coming out; a gasket 101 is further disposed between the front bearing 10 and the retaining spring 102, and the gasket 101 can be used to prevent the front bearing 10 and the retaining spring 102 from rubbing against each other and causing wear.

[0104] Please combine Figure 2As shown, the rear bearing 11 is located at the axial front end of the first extension part 203, and the end of the first extension part 203 abuts against the end face of the rear bearing 11. The first extension part 203 can provide axial positioning for the rear bearing 11; the first extension part 203 can be processed according to the installation position of the rear bearing 11 to obtain the required positioning size. This arrangement avoids setting the motor shaft 1 in a stepped shape, and the rear bearing 11 is limited by the stepped part of the motor shaft 1, which can simplify the processing technology of the motor shaft 1 and reduce the manufacturing cost.

[0105] In this embodiment, the base 301 includes a support portion 303 extending axially backward from the main body 302, the inner stator assembly 3 includes an annular sleeve 31 fixed to the outer circumferential surface of the support portion 303, and the inner circumferential wall of the inner stator core 33 is fixed to the outer surface of the annular sleeve 31. Since the annular sleeve 31 and the inner stator core 33 are made of the same material, the material properties of the two are similar, so when the inner stator core 33 is pressed onto the annular sleeve 31, no cutting waste is generated, and the stable bonding force between the two can greatly reduce or even avoid the possibility of relative sliding, thereby ensuring the safety of the outer rotor motor 100 during operation.

[0106] 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; 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, wherein the main body is sleeved on the outer periphery of the motor shaft; characterized in that: The base includes a supporting portion extending axially backward from the main body, the inner stator assembly includes an annular sleeve fixed on the outer circumferential surface of the supporting portion, and the inner circumferential wall of the inner stator core is fixed on the outer surface of the annular sleeve.

2. The outer rotor motor according to claim 1, characterized in that: The hardness of the support portion is smaller than that of the annular sleeve, the outer diameter of the support portion is larger than the inner diameter of the annular sleeve, and the inner circumferential surface of the annular sleeve is fitted on the outer circumferential surface of the support portion.

3. The outer rotor motor according to claim 1 or 2, characterized in that: The hardness of the outer surface of the annular sleeve in contact with the inner peripheral wall of the inner stator core is greater than the hardness of the supporting portion.

4. The outer rotor motor according to claim 2, characterized in that: The material of the inner stator core is the same as that of the annular sleeve, and both are made of steel.

5. The outer rotor motor according to claim 4, characterized in that: The outer diameter of the annular sleeve is greater than the inner diameter of the inner stator core, and the inner stator core is fixed to the outer peripheral surface of the annular sleeve in an interference fit manner.

6. The outer rotor motor according to claim 5, characterized in that: The axial lengths of the support portion and the annular sleeve are not greater than the axial length of the inner stator core; a step portion is provided at the connection between the main body portion and the support portion, and the end of the annular sleeve abuts against the step portion.

7. The outer rotor motor according to claim 1, characterized in that: The inner stator assembly comprises an inner stator plastic package sleeved on the inner stator iron core and a plurality of windings wound on the inner stator plastic package.

8. The outer rotor motor according to claim 1, characterized in that: The outer rotor assembly comprises 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 on 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 1, characterized in that: The outer rotor motor includes a front bearing accommodated in the axial front end of the base and a rear bearing accommodated in the axial rear end of the inner stator core, the motor shaft is supported in the inner stator bracket through the front bearing, the outer peripheral surface of the rear bearing is attached to the inner peripheral wall of the inner stator core, and the motor shaft is supported at the axial rear end of the inner stator core through the rear bearing.

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