Motor and its assembly structure

Abstract

This invention provides an electric motor and its assembly structure. The motor assembly structure includes a stator, a first end cover, a second end cover, and fasteners for fixing the stator, the first end cover, and the second end cover. The stator includes a central iron core, a first side iron core, and a second side iron core. The inner edge of the first end cover has a first inner arc surface, and the outer edge of the first side iron core has a first outer arc surface that is interference-fitted with the first inner arc surface. The inner edge of the second end cover has a second inner arc surface, and the outer edge of the second side iron core has a second outer arc surface that is clearance-fitted with the second inner arc surface. The electric motor and its assembly structure provided by this invention, through the positioning fit between the first side iron core and the first end cover, and the positioning fit between the second side iron core and the second end cover, can effectively improve the coaxiality of the stator and the end cover, thereby improving the coaxiality of the stator and the rotor and reducing the air gap between the rotor and the stator.

Description

[0001] This application is a divisional application of the invention patent application with application number 201911025229.X, application date October 25, 2019, and invention title "Electric Motor and Assembly Structure Thereof". Technical Field

[0002] This invention belongs to the field of electric motor technology, and more specifically, relates to an electric motor and its assembly structure. Background Technology

[0003] In the field of electric motors, single-phase asynchronous motors and similar types of motors generally adopt an assembly method with a clearance fit between the stator, front end cover, and rear end cover due to manufacturing cost considerations. This assembly method results in low coaxiality of the stator, end cover, and rotor. Moreover, in this assembly method, the air gap between the rotor and stator is large, the amount of silicon steel and enameled wire used in the stator and rotor is large, the material utilization rate is low, and a larger volume of electromagnetic materials is required to achieve the output power, resulting in higher electromagnetic costs. Summary of the Invention

[0004] The purpose of this invention is to provide a motor assembly structure to solve the technical problems of low coaxiality between the stator and rotor and long air gap between the stator and rotor in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a motor assembly structure is provided, including a stator, a first end cover and a second end cover respectively disposed on both sides of the stator, and fasteners for fixing the stator, the first end cover and the second end cover. The stator includes a central iron core, a first side iron core disposed facing the first end cover and a second side iron core disposed facing the second end cover. The inner edge of the first end cover has a first inner arc surface, the outer edge of the first side iron core has a first outer arc surface that is interference-fitted with the first inner arc surface, the inner edge of the second end cover has a second inner arc surface, and the outer edge of the second side iron core has a second outer arc surface that is clearance-fitted with the second inner arc surface.

[0006] Furthermore, the thickness of the first side core is h1, the thickness of the second side core is h3, and h1≥5mm, h1≥h3.

[0007] Furthermore, the depth of the first inner arc surface along its axial direction is L1, where L1 ≥ 5 mm.

[0008] Furthermore, the central iron core is polygonal in shape, and the first side iron core has the first outer arc surface, while the second side iron core has the second outer arc surface.

[0009] Furthermore, the center of the first outer arc surface coincides with the center of the first side core, and the center of the second outer arc surface coincides with the center of the second side core.

[0010] Furthermore, the distance between the two sides of the first side core is a1, the diameter of the first outer arc surface is d1, and (a1 / cos20°)≥d1>a1.

[0011] Furthermore, the distance between the two sides of the second side core is a1, and the diameter of the second outer arc surface is d1.

[0012] Furthermore, the distance between the two sides of the central iron core is a2, and a1 = a2.

[0013] Furthermore, the edge of the first end cap is provided with a plurality of first mounting holes, the edge of the central iron core is provided with a plurality of second mounting holes, the edge of the second end cap is provided with a third mounting hole, and fasteners pass through the first mounting holes, the second mounting holes and the third mounting holes. The second mounting holes are distributed circumferentially with the center of the central iron core as the center.

[0014] Furthermore, the first end cap is provided with a first flange that contacts the surface of the central iron core, the second end cap is provided with a second flange that contacts the surface of the central iron core, the first mounting hole is opened on the first flange, and the second mounting hole is opened on the second flange.

[0015] Furthermore, the distance between the center of the second mounting hole and the center of the central iron core is 0.5D3, the diameter of the first outer arc surface is d1, and (D3-d1)≥18mm.

[0016] Furthermore, each corner of the central iron core is provided with a third outer arc surface, the center of the third outer arc surface coincides with the center of the central iron core, the diameter of the third outer arc surface is d2, the diameter of the second mounting hole is D2, the distance between the center of the second mounting hole and the center of the central iron core is 0.5D3, and d2-(D2+D3)≥2.2mm.

[0017] Furthermore, the four corners of the central iron core are all chamfered, the distance between the two chamfer tangents at opposite corners of the central iron core is d2, the diameter of the second mounting hole is D2, the distance between the center of the second mounting hole and the center of the central iron core is 0.5D3, and d2-(D2+D3)≥2.2mm.

[0018] Furthermore, the depth of the first inner arc surface along its axial direction is L1, the diameter of the first inner arc surface is D4, the diameter of the first outer arc surface is d1, the thickness of the first side core is h1, D4=d1, and L1-h1≥10mm.

[0019] Furthermore, the connection between the first flange and the first inner arc surface has a rounded corner with a radius of R1, where R1 ≤ 2 mm.

[0020] Furthermore, the depth of the second inner arc surface along its axial direction is L2, the diameter of the second inner arc surface is D5, the diameter of the second outer arc surface is d3, the thickness of the first side core is h1, D5=d3, and L2-h3≥10mm.

[0021] Furthermore, the connection between the second flange and the second inner arc surface has a chamfer C, the axial depth of which is less than or equal to 1 mm.

[0022] Furthermore, the first end cover has a first bearing chamber on the side away from the stator, and the second end cover has a second bearing chamber on the side away from the stator. The first bearing chamber, the second bearing chamber, and the inner circular surface of the stator are coaxially arranged.

[0023] Furthermore, the first side core, the middle core, and the second side core are all formed by stacking slices.

[0024] Furthermore, the first inner arc surface of the first end cover and the first outer arc surface of the stator are press-fitted or temperature difference-fitted.

[0025] The present invention also provides an electric motor, including the above-described electric motor assembly structure, and further including a rotor and a first bearing and a second bearing disposed at both ends of the rotor, wherein the first bearing is disposed inside the first end cover and the second bearing is disposed inside the second end cover.

[0026] The beneficial effects of the motor and its assembly structure provided by the present invention are as follows: Compared with the prior art, the motor assembly structure of the present invention includes a stator, a first end cover, a second end cover, and fasteners for fixing the above three components. The stator includes a central iron core and a first side iron core and a second side iron core respectively disposed on both sides of the central iron core. The first side iron core has a first outer arc surface, and the first end cover has a first inner arc surface, with the first inner arc surface and the first outer arc surface being interference-fitted; the second side iron core has a second outer arc surface, and the second end cover has a second inner arc surface, with the second inner arc surface and the second outer arc surface being clearance-fitted; thus, through the positioning fit of the first side iron core and the first end cover, and the positioning fit of the second side iron core and the second end cover, the coaxiality of the stator and the end cover can be effectively improved, thereby improving the coaxiality of the stator and the rotor and reducing the air gap between the rotor and the stator. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A three-dimensional structural diagram of the stator provided in an embodiment of the present invention;

[0029] Figure 2 The main view of the stator provided in the embodiment of the present invention Figure 1 ;

[0030] Figure 3 The main view of the stator provided in the embodiment of the present invention Figure 2 ;

[0031] Figure 4 A left view of the stator provided in an embodiment of the present invention;

[0032] Figure 5 A cross-sectional view of the first end cap provided in an embodiment of the present invention;

[0033] Figure 6 A cross-sectional view of the second end cap provided in an embodiment of the present invention;

[0034] Figure 7 A half-sectional view of a motor provided for an embodiment of the present invention.

[0035] Among them, the reference numerals in the figures are:

[0036] 1-Stator; 11-First side core; 111-First outer arc surface; 12-Second side core; 121-Second outer arc surface; 13-Middle core; 131-Third outer arc surface; 132-Second mounting hole; 13-Middle core; 14-Inner arc surface; 15-Slot type; 2-First end cover; 21-First inner arc surface; 22-First flange; 23-First bearing chamber; 24-First mounting hole; 3-Second end cover; 31-Second inner arc surface; 32-Second flange; 33-Second bearing chamber; 34-Third mounting hole; 4-Fastener; 5-Rotor; 6-First bearing; 7-Second bearing. Detailed Implementation

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0039] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] Please see Figures 1 to 3The motor assembly structure provided in the embodiments of the present invention will now be described. In one embodiment of the motor assembly structure, the motor assembly structure includes a stator 1, a first end cover 2, a second end cover 3, and fasteners 4. The stator 1 includes a first side core 11, a second side core 12, and a central core 13. The first side core 11 and the second side core 12 are respectively disposed on both sides of the central core 13. The first end cover 2 is interference-fitted to the first side core 11, and the second end cover 3 is clearance-fitted to the second side core 12. More specifically, the inner edge of the first end cover 2 has a first inner arc surface 21, and the outer edge of the first side core 11 has a first outer arc surface 111. The first inner arc surface 21 and the first outer arc surface 111 are interference-fitted, so that the first end cover 2 and the stator 1 are interference-fitted. The inner edge of the second end cover 3 has a second inner arc surface 31, and the outer edge of the second side core 12 has a second outer arc surface 121. The second inner arc surface 31 and the second outer arc surface 121 are clearance-fitted, so that the second end cover 3 and the stator 1 are clearance-fitted. The fit between the first outer arc surface 111 and the first inner arc surface 21 has a radial positioning effect on the first end cover 2, improving the coaxiality of the stator 1 and the first end cover 2. The fit between the second outer arc surface 121 and the second inner arc surface 31 makes it easier to assemble the second end cover 3 and the stator 1. Both the first end cover 2 and the second end cover 3 contain bearing chambers. The increased coaxiality of the stator 1, the first end cover 2, and the second end cover 3 improves the coaxiality of the stator 1 and the bearings, further improving the coaxiality of the stator 1 and the rotor 5, ensuring more stable output power. The fit between the first outer arc surface 111 and the first inner arc surface 21, as well as the fit between the second outer arc surface 121 and the second inner arc surface 31, allows the second end cover 3 and the first end cover 2 to be embedded in the front and rear sides of the stator 1 respectively, ensuring the coaxiality of the stator 1 and the rotor 5. This reduces the air gap between the rotor 5 and the stator 1, decreases the motor's magnetic reluctance, and achieves higher output efficiency with the same volume of electromagnetic material, thereby improving electromagnetic utilization.

[0042] The motor assembly structure in the above embodiment includes a stator 1, a first end cover 2, a second end cover 3, and fasteners 4 for fixing the three components. The stator 1 includes a central iron core 13 and a first side iron core 11 and a second side iron core 12 respectively disposed on both sides of the central iron core 13. The first side iron core 11 has a first outer arc surface 111, and the first end cover 2 has a first inner arc surface 21. The first inner arc surface 21 and the first outer arc surface 111 are interference-fitted. The second side iron core 12 has a second outer arc surface 121, and the second end cover 3 has a second inner arc surface 31. The second inner arc surface 31 and the second outer arc surface 121 are clearance-fitted. In this way, through the positioning fit of the first side iron core 11 and the first end cover 2, and the positioning fit of the second side iron core 12 and the second end cover 3, the coaxiality of the stator 1 and the end cover can be effectively improved, thereby improving the coaxiality of the stator 1 and the rotor 5 and reducing the air gap between the rotor 5 and the stator 1.

[0043] Please see Figure 4 In one embodiment of the stator 1, the thickness of the first side core 11 is h1, the thickness of the middle core 13 is h2, and the thickness of the second side core 12 is h3. Since the first outer arc surface 111 of the first side core 11 mates with the first inner arc surface 21 of the first end cover 2, and the second outer arc surface 121 of the second side core 12 mates with the second inner arc surface 31 of the second end cover 3, the maximum depth to which the first side core 11 extends into the first end cover 2 is h1, and the maximum depth to which the second side core 12 extends into the second end cover 3 is h3. If h1 and h3 are too small, even if the first end cover 2 is in an interference fit with the first side core 11, it may still detach from the stator 1, resulting in an unstable interference fit connection between the two. The second end cover 3 is also prone to radial wobbling relative to the second side core 12, leading to poor assembly and low assembly accuracy. To prevent the first end cap 2 from falling off, h1≥5mm; the first end cap 2 is a stretch-formed cap body, and the bend of the first end cap 2 is arc-shaped, which will reduce the fitting thickness between the first end cap 2 and the first side iron core 11. The second end cap 3 is a die-cast cap body, and the arc diameter of its bend is smaller, even 90 degrees, which will not reduce the fitting thickness between the second end cap 3 and the second side iron core 12. Therefore, h1≥h3.

[0044] Optionally, the depth of the first inner arc surface 21 along its axial direction is L1, where L1 ≥ 5mm, to ensure the effective fit thickness between the first end cover 2 and the first side core 11, thereby enhancing the reliability of the interference fit between the first end cover 2 and the first side core 11.

[0045] Please see Figures 1 to 3 In one embodiment of the stator 1, the first side core 11 has a first outer arc surface 111, and the second side core 12 has a second outer arc surface 121. Optionally, the first side core 11, the middle core 13, and the second side core 12 are polygonal, such as rectangular. The first outer arc surface 111 is located at the corner of the first side core 11, and only the corner of the first side core 11 mates with the first end cover 2. The second outer arc surface 121 is located at the corner of the second side core 12, and only the corner of the second side core 12 has a clearance fit with the second end cover 3. The larger the two mating areas mentioned above, the greater the positioning effect of the first side core 11 on the first end cover 2 and the coaxial positioning effect of the second side core 12 on the second end cover 3. However, when the two mating areas are too large, that is, when the areas of the first outer arc surface 111 and the second outer arc surface 121 are larger, the material of the stator 1 is reduced, and the electromagnetic performance is reduced. Therefore, the area of ​​the first outer arc surface 111 and the second outer arc surface 121 should be selected by comprehensively considering the motor performance and assembly performance.

[0046] Furthermore, both the first side core 11 and the second side core 12 are square. The center of the first outer arc surface 111 coincides with the center of the first side core 11, and the center of the second outer arc surface 121 coincides with the center of the second side core 12. The four first outer arc surfaces 111 form the circumcircle of the first side core 11, with the center of this circumcircle coinciding with the center of the first outer arc surface 111, thus ensuring the coaxiality of the stator 1 and the first end cover 2 during assembly. Similarly, the four second outer arc surfaces 121 form the circumcircle of the second side core 12, with the center of this circumcircle coinciding with the center of the second outer arc surface 121, thus ensuring the coaxiality of the stator 1 and the second end cover 3 during assembly.

[0047] Please see Figure 3 In one embodiment of the stator 1, the center of the first outer arc surface 111 coincides with the center of the first side core 11, the distance between the two sides of the first side core 11 is a1, and the diameter of the first outer arc surface 111 is d1, (a1 / cos20°)≥d1>a1. The diameter d1 corresponds to the circumcircle of the first side core 11, and the diameter d1 of the circumcircle is always greater than the side length a1, i.e., d1>a1. Figure 3 In the equation, cosθ = (0.5a1) / (0.5d1). The smaller θ is, the smaller d1 is, resulting in more material being cut away, reduced electromagnetic performance, and worse performance of the motor stator 1. Therefore, an excessively small d1 will affect motor performance. However, an excessively large d1 will result in an insufficient area of ​​the first outer arc surface 111, which will not be able to guarantee the mating area between the stator 1 and the first end cover 2. Therefore, a1 / d1 ≥ cos20°, and θ is at most 20° to ensure the mating area between the stator 1 and the first end cover 2, thereby ensuring coaxiality.

[0048] Optionally, the first side core 11 and the second side core 12 have the same structure and dimensions. The distance between the two sides of the second side core 12 is a1. If both the first side core 11 and the second side core 12 are squares, their side lengths are equal. The diameter of the second outer arc surface 121 is d1, where (a1 / cos20°) ≥ d1 > a1. Please refer to [link / reference]. Figure 6 and Figure 7 In one embodiment of the motor assembly structure, the edge of the first end cover 2 is provided with a plurality of first mounting holes 24, the edge of the central iron core 13 is provided with a plurality of second mounting holes 132, the edge of the second end cover 3 is provided with a third mounting hole 34, and the fastener 4 passes through the first mounting hole 24, the second mounting hole 132 and the third mounting hole 34.

[0049] Optionally, when the central core 13, the first side core 11, and the second side core 12 are all square, the side length of the central core 13 is a2, and a1 = a2, so that the side lengths of the central core 13, the first side core 11, and the second side core 12 are all the same, thereby making the side of the stator 1 that is not cut into a circle a flat surface.

[0050] The central core 13, the first side core 11, and the second side core 12 all have an inner circular surface 14 through which the rotor 5 passes, and also have a slot 15. The structure and dimensions of the inner circular surface 14 and the slot 15 of the above three are the same. The first side core 11, the central core 13, and the second side core 12 can all be formed by stacking slices. Each slice has an inner circular surface 14 and a slot 15. The inner circular surfaces 14 are aligned with each other, and the slots 15 are aligned with each other. The first end cover 2 and the second end cover 3 are both provided with bearing chambers for installing bearings, and the bearings are used to support the rotor 5. The bearing chamber in the first end cover 2 is the first bearing chamber 23, and the bearing chamber in the second end cover 3 is the second bearing chamber 33. The first bearing chamber 23, the second bearing chamber 33, and the inner circular surface 14 of the stator 1 are coaxially arranged.

[0051] When assembling the first end cover 2 and the second end cover 3: First, the first end cover 2 and the first side core 11 are connected by an interference fit, the first mounting hole 24 and the second mounting hole 132 are aligned, and the first inner arc surface 21 and the first outer arc surface 111 are fitted together to improve the coaxiality of the first bearing chamber 23 of the first end cover 2 and the inner arc surface 14 of the stator 1, so that the first end cover 2 is fastened to the stator 1; then, the second end cover 3 is fitted to the second side core 12 at room temperature with a clearance fit, the third mounting hole 34 and the second mounting hole 132 are aligned, and the second inner arc surface 31 and the second outer arc surface 121 are fitted together to improve the coaxiality of the second bearing chamber 33 of the second end cover 3 and the inner arc surface 14 of the stator 1; the fastener 4 passes through the first mounting hole 24, the second mounting hole 132 and the third mounting hole 34 to fix the first end cover 2, the stator 1 and the second end cover 3 to each other.

[0052] Optionally, the first mounting hole 24 and the second mounting hole 132 are open holes, the third mounting hole 34 is a threaded hole, and the fastener 4 is a threaded component. The fastener 4 presses the first end cover 2, the stator 1 and the second end cover 3 together and is threadedly connected to the second end cover 3.

[0053] Optionally, the first end cap 2 and the first side core 11 are press-fitted or subjected to a temperature difference method. Press-fitting method: Clean the first inner arc surface 21 and the first outer arc surface 111, align the first mounting hole 24 and the second mounting hole 132, align the first inner arc surface 21 and the first outer arc surface 111, and use a heavy object or hydraulic press to press the first end cap 2 tightly onto the stator 1. The first side core 11 of the stator 1 is pressed into the cylindrical cavity formed by the first inner arc surface 21. Temperature difference method: Clean the first inner arc surface 21 and the first outer arc surface 111, heat the first end cap 2 to cause it to expand moderately, and then install the first end cap 2 onto the stator 1, aligning the first mounting hole 24 and the second mounting hole 132. After cooling, the first end cap 2 shrinks, and the first end cap 2 and the stator 1 are press-fitted. The first end cap 2 and the first side core 11 can also be press-fitted using manual hammering, cold fitting, or other methods.

[0054] Please see Figure 2 and Figure 3 There are multiple second mounting holes 132, which are circumferentially distributed around the center of the central iron core 13, so that the center of all the second mounting holes 132 is equidistant from the center of the central iron core 13. This further improves the coaxiality of the inner circular surface 14 of the stator 1 and the bearing chamber when the first mounting hole 24, the second mounting hole 132, and the third mounting hole 34 are aligned. For example, there are four second mounting holes 132, which are respectively opened at the four corners of the central iron core 13. The second mounting holes 132 do not pass through the first side iron core 11 and the second side iron core 12, that is, they are set at the tangent circles of the first side iron core 11 and the second side iron core 12, so that the first end cover 2 and the second end cover 3 are directly attached to the surface of the central iron core 13 and aligned with the mounting holes.

[0055] Please see Figure 5 and Figure 6 In one embodiment of the motor mounting structure, the first end cover 2 is provided with a first flange 22, which extends radially from the end of the first inner arc surface 21. The surface of the first flange 22 is used to fit tightly against the surface of the central iron core 13. A first mounting hole 24 is provided in the first flange 22 to prevent the edge of the first end cover 2 from deforming when the fastener 4 is tightened. The second end cover 3 is provided with a second flange 32, which extends radially from the end of the second inner arc surface 31. The surface of the second flange 32 is used to fit tightly against the other surface of the central iron core 13. A third mounting hole 34 is provided in the second flange 32 to prevent the edge of the second end cover 3 from deforming when the fastener 4 is tightened. In this way, compared with the conventional use of cantilever screws for the end covers at the front and rear of the stator 1, the stator 1 provides support for both the front and rear end covers, effectively reducing the deformation of the outer edge of the end cover.

[0056] Please see Figure 2In one embodiment of the stator 1, the center of all the second mounting holes 132 is equidistant from the center of the central core 13. After the first end cover 2 and the second end cover 3 are installed, sufficient space needs to be reserved for the installation of the fastener 4. Therefore, the distance between the outer wall of the first mounting hole 24 and the first end cover 2 cannot be too small. Consequently, the distance between the center of the second mounting hole 132 and the adjacent first outer arc surface 111 cannot be too small. The distance between the center of the second mounting hole 132 and the center of the central core 13 is 0.5D3, and the diameter of the first outer arc surface 111 is d1, where (D3-d1)≥18mm to ensure sufficient installation space for the fastener 4. For example, D3-d1 is equal to 18mm, 19mm, 20mm, etc.

[0057] Please see Figure 2 In one embodiment of the stator 1, a third outer arc surface 131 is provided at each corner of the central core 13. The center of the third outer arc surface 131 coincides with the center of the central core 13, that is, the outer periphery of the central core 13 has an circumscribed circle with a diameter of d2. The diameter of the second mounting hole 132 is D2. The distance between the inner wall of the second mounting hole 132 and the surface of the circumscribed circle of the central core 13 cannot be too close, otherwise the strength at the circumscribed circle will be very low, unable to withstand large torsional and radial forces, and easily break under stress. To ensure the strength at the four corners of the central core 13, d2-(D2+D3)≥2.2mm, and d2-(D2+D3) can be 2.5mm, 2.7mm, 3mm, etc.

[0058] In another embodiment of the stator 1, chamfers are provided at each corner of the central core 13. The distance between the tangents of the two chamfers at opposite corners of the central core 13 is d2, and the diameter of the second mounting hole 132 is D2. Similarly, the distance between the inner wall of the second mounting hole 132 and the chamfer surface cannot be too close, otherwise the strength of the corners of the central core 13 will be very low, unable to withstand large torsional and radial forces, and prone to breakage under stress. To ensure the strength at the four corners of the central core 13, d2-(D2+D3)≥2.2mm, and d2-(D2+D3) can be 2.5mm, 2.7mm, 3mm, etc.

[0059] Please see Figure 5In one embodiment of the first end cap 2, the depth of the first inner arc surface 21 along its axial direction is L1, the diameter of the first inner arc surface 21 is D4, and the diameter of the first outer arc surface 111 is d1. To ensure the first inner arc surface 21 and the first outer arc surface 111 mate, D4 ​​= d1, but the tolerance zone of D4 is below the tolerance zone of d1. In this embodiment, the first side core 11 is fully inserted into the first end cap 2. When the thickness h1 of the first side core 11 is constant, the smaller the difference between the depth L1 and h1 of the first inner arc surface 21 along its axial direction, the smaller the distance between the first side core 11 and the heat dissipation hole on the first end cap 2. Since the heat dissipation hole is formed by punching, the material around the heat dissipation hole will deform. If the distance between the first side core 11 and the heat dissipation hole is too close, it will affect the fitting accuracy. L1-h1≥10mm ensures that the first side core 11 has a certain distance from the heat dissipation hole after installation, avoiding deformation of the heat dissipation hole edge from affecting the fitting accuracy.

[0060] Please see Figure 5 In one embodiment of the first end cover 2, the connection between the first flange 22 and the first inner arc surface 21 has a rounded corner. Since the first inner arc surface 21 and the first outer arc surface 111 are in an interference fit, the rounded corner guides the assembly of the first end cover 2 and the stator 1, preventing the edges from squeezing and breaking during assembly. The radius of the rounded corner is R1. If R1 is too large, the fit depth between the first inner arc surface 21 and the first outer arc surface will decrease accordingly, which may lead to a decrease in the reliability of the interference fit. Therefore, R1 ≤ 2mm.

[0061] Please see Figure 6 In one embodiment of the second end cover 3, the depth of the second inner arc surface 31 along its axial direction is L2, the diameter of the second inner arc surface 31 is D5, and the diameter of the second outer arc surface 121 is d3. To ensure the second inner arc surface 31 and the second outer arc surface 121 mate, D5 = d3, but the tolerance zone of D5 is above the tolerance zone of d1. In this embodiment, the second side core 12 is fully inserted into the second end cover 3. When the thickness h3 of the second side core 12 is constant, the smaller the difference between the depth L2 and h3 of the first inner arc surface 21 along its axial direction, the smaller the space required for winding installation. To ensure the reliability of winding installation, L2 - h3 ≥ 10 mm, ensuring sufficient space between the second side core 12 and the end of the second inner arc surface 31 away from the stator 1. Here, d3 can be equal to d1.

[0062] Please see Figure 6In one embodiment of the second end cover 3, the connection between the second flange 32 and the second inner arc surface 31 has a chamfer C, the axial depth of which is less than or equal to 1 mm. Since the first inner arc surface 21 and the first outer arc surface 111 are in clearance fit, the chamfer provides a guiding function for the assembly of the second end cover 3 and the stator 1. However, the edge of the chamfer C is angular, so when the second end cover 3 and the stator 1 are slightly misaligned, it will not cause the second end cover 3 to slide off the stator 1 like a rounded corner, making it easier to install the second end cover 3.

[0063] Please see Figure 7 The present invention also provides an electric motor, which includes the motor assembly structure of any of the above embodiments, and further includes a rotor 5 and a first bearing 6 and a second bearing 7 disposed at both ends of the rotor 5. The first bearing 6 and the second bearing 7 are both used to support the rotor 5, so that the rotor 5 rotates relative to the stator 1. The first bearing 6 is disposed in the first end cover 2, and the second bearing 7 is disposed in the second end cover 3. The first end cover 2 is provided with a first bearing chamber 23, and the second end cover 3 is provided with a second bearing chamber 33.

[0064] The motor provided in the above embodiment adopts the above-described motor assembly structure. Through the positioning and cooperation of the first side iron core 11 and the first end cover 2, and the positioning and cooperation of the second side iron core 12 and the second end cover 3, the coaxiality of the stator 1 and the end cover can be effectively improved, thereby improving the coaxiality of the stator 1 and the rotor 5. Moreover, the overall axial length of the motor is shortened, and the air gap length between the rotor 5 and the stator 1 is reduced.

[0065] Specifically, when assembling the motor in the above embodiment, the first bearing 6 is first placed into the first bearing chamber 23 of the first end cover 2, and then the first end cover 2 is press-fitted with the first side iron core 11 of the stator 1. Then the rotor 5 passes through the inner circular surface 14 of the stator 1 and is coaxially arranged with the inner circular surface 14 of the stator 1. Then the second bearing 7 is placed into the second bearing chamber 33 of the second end cover 3, and then the second end cover 3 is assembled to the second side iron core 12 of the stator 1. The fastener 4 passes through the first end cover 2, the middle iron core 13 and the second end cover 3 to fix the first end cover 2, the middle iron core 13 and the second end cover 3.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A motor assembly structure, characterized in that: The device includes a stator, a first end cap and a second end cap respectively disposed on both sides of the stator, and fasteners for fixing the stator, the first end cap and the second end cap. The stator includes a central iron core, a first side iron core facing the first end cap and a second side iron core facing the second end cap. The inner edge of the first end cap has a first inner arc surface, and the outer edge of the first side iron core has a first outer arc surface that mates with the first inner arc surface. The inner edge of the second end cap has a second inner arc surface, and the outer edge of the second side iron core has a second outer arc surface that mates with the second inner arc surface. The first end cap is formed by stretching, and the second end cap is formed by die casting. The first end cap has multiple first mounting holes on its edge, the middle iron core has multiple second mounting holes on its edge, and the second end cap has a third mounting hole on its edge. Fasteners pass through the first mounting holes, the second mounting holes, and the third mounting holes. The second mounting holes are circumferentially distributed with the center of the middle iron core as the center.

2. The motor assembly structure as described in claim 1, characterized in that: The first outer arc surface and the first inner arc surface are interference-fitted.

3. The motor assembly structure as described in claim 1, characterized in that: The second outer arc surface and the second inner arc surface are in clearance fit.

4. The motor assembly structure as described in claim 1, characterized in that: The thickness of the first side core is h1, and the thickness of the second side core is h3, where h1 ≥ 5 mm and h1 ≥ h3.

5. The motor assembly structure as described in claim 4, characterized in that: The depth of the first inner arc surface along its axial direction is L1, where L1 ≥ 5 mm.

6. The motor assembly structure as described in claim 1, characterized in that: The central iron core is polygonal in shape.

7. The motor assembly structure as described in claim 6, characterized in that: The center of the first outer arc surface coincides with the center of the first side core, and the center of the second outer arc surface coincides with the center of the second side core.

8. The motor assembly structure as described in claim 6, characterized in that: The distance between the two sides of the first side core is a1, the diameter of the first outer arc surface is d1, and (a1 / cos20°)≥d1>a1.

9. The motor assembly structure as described in claim 8, characterized in that: The distance between the two sides of the central iron core is a2, and a1 = a2.

10. The motor assembly structure as described in claim 1, characterized in that: The first end cap has a first flange that contacts the surface of the central iron core, and the second end cap has a second flange that contacts the surface of the central iron core. The first mounting hole is formed on the first flange, and the second mounting hole is formed on the second flange.

11. The motor assembly structure as described in claim 1, characterized in that: The diameter of the circumference where the center of the second mounting hole is located is D3, and the diameter of the first outer arc surface is d1, (D3-d1)≥18mm.

12. The motor assembly structure as described in claim 1, characterized in that: Each corner of the central iron core is provided with a third outer arc surface. The center of the third outer arc surface coincides with the center of the central iron core. The diameter of the third outer arc surface is d2. The diameter of the second mounting hole is D2. The diameter of the circumference of the center of the second mounting hole is D3. d2-(D2+D3)≥2.2mm.

13. The motor assembly structure as described in claim 1, characterized in that: Each corner of the central iron core is chamfered, the distance between the two chamfer tangents at opposite corners of the central iron core is d2, the diameter of the second mounting hole is D2, the diameter of the circumference of the center of the second mounting hole is D3, and d2-(D2+D3)≥2.2mm.

14. The motor assembly structure as described in claim 10, characterized in that: The depth of the first inner arc surface along its axial direction is L1, the diameter of the first inner arc surface is equal to the diameter of the first outer arc surface, the thickness of the first side core is h1, and L1-h1≥10mm.

15. The motor assembly structure as described in claim 14, characterized in that: The connection between the first flange and the first inner arc surface has a rounded corner with a radius of R1, where R1 ≤ 2 mm.

16. The motor assembly structure as described in claim 10, characterized in that: The depth of the second inner arc surface along its axial direction is L2, the diameter of the second inner arc surface is equal to the diameter of the second outer arc surface, the thickness of the second side core is h3, and L2-h3≥10mm.

17. The motor assembly structure as described in claim 16, characterized in that: The connection between the second flange and the second inner arc surface has a chamfer C, the axial depth of which is less than or equal to 1 mm.

18. The motor assembly structure as described in any one of claims 1-17, characterized in that: The first inner arc surface of the first end cover and the first outer arc surface of the stator are press-fitted or temperature difference-fitted.

19. An electric motor, characterized in that: The motor assembly structure includes any one of claims 1-18, and further includes a rotor and a first bearing and a second bearing disposed at both ends of the rotor, wherein the first bearing is disposed within the first end cover and the second bearing is disposed within the second end cover.

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