External rotor motor

Abstract

The utility model discloses an external rotor motor, which comprises a rotating shaft extending along the axial direction, an external rotor assembly connected to the rotating shaft and an internal stator assembly located between the rotating shaft and the external rotor assembly, and the external rotor assembly comprises a first shell fixed on the rotating shaft. The inner stator assembly comprises a stator iron core accommodated in the first shell and a rack for supporting the stator iron core, the rotating shaft penetrates through the stator iron core, one axial end of the rotating shaft is supported on the rack, the stator iron core has a taper, and the production of aluminum skimmings is avoided or reduced while the safety is ensured.

Description

Technical Field

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

[0002] The aluminum alloy bracket of the outer rotor motor stator assembly is pressed into the inner hole of the stator core with an interference fit. The interference fit size adopts different interference fit sizes according to the matching diameter. However, during the press-fitting process, due to the difference in material properties between steel and aluminum, the aluminum bracket will be cut by the silicon steel sheet to produce aluminum chips. Too much aluminum chips will accumulate in our chip storage groove, causing the steel sheet to be squeezed and deformed. The aluminum chips will be discharged from the press-fit stop surface of the stator bracket and fall into the motor, causing poor insulation voltage resistance and noise.

[0003] The use of refrigerated aluminum brackets for press-fitting can avoid cutting aluminum chips, but the entire market currently uses liquid nitrogen for rapid cooling, which has certain safety risks and is expensive.

[0004] Therefore, it is necessary for us to develop a new outer rotor motor to ensure safety while avoiding or reducing the generation of aluminum chips. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present invention provides an outer rotor motor which effectively reduces the generation of aluminum chips and ensures safety.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] An outer rotor motor comprises an axially extending shaft, an outer rotor assembly connected to the shaft, and an inner stator assembly located between the shaft and the outer rotor assembly, wherein the outer rotor assembly comprises a first shell fixed to the shaft, the inner stator assembly comprises a stator core accommodated in the first shell and a frame supporting the stator core, the shaft passes through the stator core and one axial end of the shaft is supported by the frame, and the stator core has a taper.

[0008] A further improvement is that the stator core is formed by stacking silicon steel sheets, and the thickness of the silicon steel sheets is 0.35 mm to 0.5 mm.

[0009] A further improvement is that the taper of the stator core is between 0.3 degrees and 0.5 degrees.

[0010] A further improvement is: the outer rotor motor also includes a second shell connected to the frame, the outer rotor assembly is accommodated in the interior of the second shell, the second shell is provided with a second annular side wall located on the outside of the first shell and a second end wall connected to the second annular side wall, the second annular side wall and / or the second end wall have an opening connecting the interior and the outside of the second shell.

[0011] A further improved solution is: the outer rotor assembly includes a fan fixed on the rotating shaft and a first bearing adjacent to the fan, the fan is located between the second end wall and the first shell to generate airflow, and the rotating shaft is supported on the second end wall through the first bearing.

[0012] A further improved solution is: the second housing is provided with a bearing chamber coaxial with the rotating shaft and a receiving chamber communicated with the bearing chamber, the first bearing is received in the bearing chamber, and the receiving chamber receives the outer rotor assembly.

[0013] A further improved solution is: the first shell is provided with a first annular side wall and a first end wall connected to the first annular side wall, the first end wall is fixed on the rotating shaft, and the first end wall and the frame are respectively located on two axial sides of the stator core.

[0014] A further improvement is: the outer rotor assembly also includes a magnetic steel frame and a plurality of magnetic steels attached to the inner wall of the first annular side wall, the magnetic steel frame abuts against the first end wall and fixes the magnetic steels, and the magnetic steels are evenly distributed on the inner wall of the first annular side wall along the circumferential direction.

[0015] A further improved solution is: the inner stator assembly includes a winding wound on the stator core, the stator core has an injection-molded insulating layer, and the insulating layer insulates and separates the winding from the stator core.

[0016] A further improved solution is: the outer rotor assembly also includes a second bearing and a retaining ring located in the frame, the rotating shaft is supported on the frame through the second bearing, and the retaining ring fixes the second bearing in the frame.

[0017] Compared with the prior art, the present invention has one or more of the following beneficial effects:

[0018] 1. A second housing connected to the frame is provided in the outer rotor motor, the outer rotor assembly is accommodated in the second housing, the second housing is provided with a second annular side wall located outside the first housing and a second end wall connected to the second annular side wall, and the second annular side wall and / or the second end wall are provided with an opening connecting the inside and the outside of the second housing, so as to improve the heat dissipation effect of the outer rotor motor and reduce the process cost;

[0019] 2. The stator core has a taper, and the waste can be squeezed between the frame and the stator core. The waste will no longer fall into the motor. This can ensure safety while avoiding or reducing the generation of aluminum chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The specific implementation methods of the present application are further described in detail below with reference to the accompanying drawings:

[0021] Figure 1 is a three-dimensional schematic diagram of an outer rotor motor in a preferred embodiment of the present application;

[0022] Figure 2 yes Figure 1 An exploded view of an outer rotor motor is shown;

[0023] Figure 3 yes Figure 1 A three-dimensional schematic diagram of some components of the outer rotor motor shown;

[0024] Figure 4 yes Figure 1 A cross-sectional view of a partial assembly of an outer rotor motor is shown.

[0025] Meaning of the reference numerals in the figures:

[0026] 100, outer rotor motor 10, rotating shaft 20, outer rotor assembly

[0027] 21. first housing 211. first annular side wall 212. first end wall

[0028] 22. Magnetic steel 23. Magnetic steel frame 24. Fan

[0029] 25. first bearing 30. inner stator assembly 31. frame

[0030] 32. stator core 33. second bearing 34. winding

[0031] 35, insulating layer 36, retaining ring 40, second housing

[0032] 41, second annular side wall 42, second end wall 43, opening

[0033] 44. Bearing chamber 45. Accommodation chamber DETAILED DESCRIPTION

[0034] 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.

[0035] Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0037] See also Figure 1 to Figure 2 As shown, an embodiment of the present application relates to an outer rotor motor 100, comprising an axially extending shaft 10, an outer rotor assembly 20 connected to the shaft, and an inner stator assembly 30 located between the shaft and the outer rotor assembly, wherein the outer rotor assembly 20 comprises a first shell 21 fixed to the shaft, the inner stator assembly 30 comprises a stator core 32 accommodated in the first shell 21 and a frame 31 supporting the stator core 32, the shaft 10 is passed through the stator core 32 and one axial end of the shaft 10 is supported on the frame 31, the outer rotor assembly 20 is fixed to the shaft 10, and the shaft 10 rotates relative to the inner stator assembly 30 along with the outer rotor assembly 20.

[0038] See also Figures 2 to 3 As shown, the outer rotor motor also includes a second shell 40 connected to the frame, the outer rotor assembly is accommodated in the interior of the second shell 40, the second shell 40 is provided with a second annular side wall 41 located on the outside of the first shell and a second end wall 42 connected to the second annular side wall, and the second annular side wall and / or the second end wall have an opening 43 connecting the interior and the outside of the second shell 40, which can improve the heat dissipation effect of the outer rotor motor and reduce the process cost.

[0039] See also Figure 2As shown, the first shell 21 is provided with a first annular side wall 211 and a first end wall 212 connected to the first annular side wall, the first end wall 212 is fixedly connected to the rotating shaft, and the first end wall 212 and the frame are respectively located on both axial sides of the stator core 32.

[0040] The outer rotor assembly includes a fan 24 fixedly connected to the rotating shaft and a first bearing 25 adjacent to the fan. The fan 24 is located between the second end wall 42 and the first housing 21 to generate airflow, and the rotating shaft is supported on the second end wall 42 through the first bearing 25. The second housing 40 is provided with a bearing chamber 44 coaxial with the rotating shaft and a receiving chamber 45 connected to the bearing chamber. The first bearing 25 is received in the bearing chamber 44, and the receiving chamber 45 receives the outer rotor assembly 20. Compared with the traditional structure in which the bearing is placed inside the motor, the bearing of the present application is placed outside, the axial dimension of the bearing is significantly lengthened, the outer diameter of the motor shaft and the bearing selection are no longer limited, and the motor can cover a larger power range. The protection of the second housing 40 during testing and use of the motor greatly reduces the danger, and the whole machine structure does not need to reserve space and air ducts for the motor, and the space utilization rate is higher.

[0041] Figure 4 It is a cross-sectional view of the outer rotor motor in the preferred embodiment of the present application. The outer rotor assembly 20 also includes a magnetic steel frame 23 and a plurality of magnetic steels 22 attached to the inner wall of the first annular side wall 211. The magnetic steel frame 23 abuts against the first end wall 212 and fixes the magnetic steels 22. The magnetic steels are evenly distributed on the inner wall of the first annular side wall along the circumferential direction.

[0042] The stator core 35 of this case has a long side a and a short side b, and the long side a and the short side b have an intersection X. The short side b is parallel to the horizontal plane, and a vertical line L1 is made perpendicular to the short side b at the intersection. The long side a has an extension line L2, and the angle between L1 and L2 is the taper α of the stator core 35. In the preferred embodiment of this case, the taper range of the stator core 35 is between 0.3 and 0.5 degrees. When the frame 31 is pressed into the stator core, waste will be generated from top to bottom. At this time, the stator core has a taper, and the waste can be squeezed between the frame and the stator core, and the waste will no longer fall into the motor, which can ensure safety while avoiding or reducing the generation of aluminum chips. In addition, in the manufacturing process of the original solution, the upper and lower inner holes of the stator core are the same size. In order to be able to be placed in the frame better, a guide smaller than the diameter of the inner hole of the stator core is generally made at the front end of the aluminum frame. In this technical solution, after the stator core is made into a taper, the front end of the core is larger than the size of the aluminum frame. At this time, the front end of the aluminum bracket no longer needs to be guided, reducing the processing cost.

[0043] The fan 24 is located in the receiving chamber 45, and the fan 24 rotates with the rotating shaft to generate airflow. The fan 24 can also be integrated with the magnetic steel frame 23. In addition, the structure of the magnetic steel 22 is tile-shaped, and the magnetic steel 22 is made of neodymium iron boron material. Of course, the structure of the magnetic steel 22 can also be ring-shaped, and the magnetic steel material is not limited to neodymium iron boron material.

[0044] The fan has blade geometry parameters, and the blade refers to the geometry of the cross section of the blade along the direction of airflow. The main performance index of the two-dimensional blade is the lift-to-drag ratio. The pressure, power loss and efficiency of the cooling fan are respectively related to the lift, drag and lift-to-drag ratio of the blade. The fan blade is also called a blade, and there are three types of fan blade cross-sectional shapes: airfoil, arc and straight edge. The arc and straight edge blades are simple in shape and have good manufacturability, and the performance can also meet the basic requirements of the cooling fan, while the cross-sectional shape of the airfoil blade is referenced to the aircraft wing, and is mostly used in the field of aeroengines. The application in the field of cooling fans can also bring high aerodynamic and noise performance, but the relative manufacturing difficulty is large, the strength of the blade tip is difficult to guarantee, and the cost is high. The parameters of the arc and straight edge structures are relatively simple, and the geometric parameters of the airfoil blades are relatively complex. The blades in this application belong to the airfoil blades mentioned here.

[0045] Furthermore, the inner stator assembly 30 further includes a second bearing 33 and a retaining ring 36 located in the frame, the rotating shaft is supported on the frame through the second bearing 33, and the retaining ring 36 fixes the second bearing 33 in the frame 31. The frame has a plurality of mounting holes and screws located in the mounting holes, and the second housing is fixedly connected to the frame 31 through the screws.

[0046] The inner stator assembly 30 includes a winding 34 wound on the stator core 32, and the stator core has an injection-molded insulating layer 35, which insulates the winding from the stator core. The openings 43 are evenly distributed along the circumferential direction on at least one of the second annular side wall or the second end wall.

[0047] Preferably, the winding 34 may also include a coil and an adhesive integrally formed on the coil. In the present embodiment, the adhesive is preferably an epoxy resin. The epoxy resin contains a variety of polar groups and highly active epoxy groups, so it has a strong bonding force with materials with high surface activity. At the same time, the cohesive strength of the epoxy cured product is also very large, so its bonding strength is very high. When the epoxy resin is cured, basically no low-molecular volatiles are produced, the volume shrinkage is small, and the corrosion resistance and dielectric properties are good. Advantages, so it is preferably used for integral molding with the coil. Of course, the adhesive is, for example, but not limited to, acrylic resins, polyurethanes, phenolic resins and other resins with similar properties. In the outer rotor motor of the present application, the winding is three-phase and is wound by multiple strands of twisted enameled wire or copper bars to form a cylindrical slotless structure.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0049] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. An outer rotor motor, comprising a rotating shaft extending in an axial direction, an outer rotor assembly connected to the rotating shaft, and an inner stator assembly located between the rotating shaft and the outer rotor assembly, wherein the outer rotor assembly comprises a first housing fixed to the rotating shaft, the inner stator assembly comprises a stator core accommodated in the first housing and a frame supporting the stator core, the rotating shaft passes through the stator core and one axial end of the rotating shaft is supported by the frame; characterized in that: The stator core has a taper.

2. The outer rotor motor according to claim 1, characterized in that: The stator core is formed by stacking silicon steel sheets, and the thickness of the silicon steel sheets is 0.35mm to 0.5mm.

3. The outer rotor motor according to claim 1, characterized in that: The taper of the stator core is between 0.3 degrees and 0.5 degrees.

4. The outer rotor motor according to claim 1, characterized in that: The outer rotor motor also includes a second shell connected to the frame, the outer rotor assembly is accommodated in the interior of the second shell, the second shell is provided with a second annular side wall located on the outside of the first shell and a second end wall connected to the second annular side wall, and the second annular side wall and / or the second end wall have an opening connecting the interior and the exterior of the second shell.

5. The outer rotor motor according to claim 4, characterized in that: The outer rotor assembly includes a fan fixed on the rotating shaft and a first bearing adjacent to the fan. The fan is located between the second end wall and the first housing to generate airflow. The rotating shaft is supported on the second end wall through the first bearing.

6. The outer rotor motor according to claim 5, characterized in that: The second housing is provided with a bearing chamber coaxial with the rotating shaft and a receiving chamber communicated with the bearing chamber, the first bearing is received in the bearing chamber, and the outer rotor assembly is received in the receiving chamber.

7. The outer rotor motor according to claim 1, characterized in that: The first shell is provided with a first annular side wall and a first end wall connected to the first annular side wall, the first end wall is fixed on the rotating shaft, and the first end wall and the frame are respectively located on two axial sides of the stator core.

8. The outer rotor motor according to claim 7, characterized in that: The outer rotor assembly also includes a magnetic steel frame and a plurality of magnetic steels attached to the inner wall of the first annular side wall, the magnetic steel frame abuts against the first end wall, the magnetic steel is fixed on the magnetic steel frame, and the magnetic steel is evenly distributed on the inner wall of the first annular side wall along the circumferential direction.

9. The outer rotor motor according to claim 1, characterized in that: The inner stator assembly comprises a winding wound on the stator core. The stator core is provided with an injection-molded insulating layer, and the insulating layer insulates and separates the winding from the stator core.

10. The outer rotor motor according to claim 1, characterized in that: The inner stator assembly further comprises a second bearing and a retaining ring located in the frame, the rotating shaft is supported on the frame through the second bearing, and the retaining ring fixes the second bearing in the frame.

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