Stator core of motor and vehicle

Abstract

One or more embodiments of the present application provide a stator core and a vehicle. The stator core may include: a main body composed of multiple layers of electromagnetic steel sheets stacked in layers, the main body being provided with at least a first through hole extending axially, a first pin located in the first through hole, a first end cover located at a first end of the main body connected to a first pin end of the first pin, and a second end cover located at a second end of the main body connected to a second pin end of the first pin, wherein the connection between the first end cover and the second end cover and the first pin generates tensile stress in the main body.

Description

[0001] This application is a divisional application of an invention patent application filed on November 23, 2018, in which the applicant is Ford Global Technologies Corporation, the invention name is a stator core of an electric motor, the application number is 201811409736.9, and the application date is November 23, 2018. Technical Field

[0002] The present application relates to a motor stator core, and in particular to a motor stator core with low iron loss and a vehicle. Background Art

[0003] Electric motors are widely used in vehicles and other fields. Generally, the motor includes a rotor located in the center and a stator that is roughly cylindrical and surrounds the rotor. The rotor and stator each have a winding made of wound wires. For the stator, during the production process, compressive stress will be generated in the radial area of ​​the stator due to the processes of stator stamping, winding / embedding, and installation and fixing. Due to the inherent magnetostrictive characteristics of the stator, compressive stress will increase the iron loss of non-oriented electromagnetic steel sheets. The stator lamination method generally adopts a buckle point structure plus an axial welding structure. These structures are conductive between the electromagnetic steel sheets, which further increases the iron loss. How to eliminate the compressive stress generated during the stator installation process is a challenge.

[0004] Japanese patent publication JP2013062892 provides a rotating electric machine that reduces iron loss by applying tensile stress to the stator. However, the inventor of the present application realizes that the design structure in the prior art is relatively complex and introduces more connection areas, so the inventor of the present application realizes that there is a need for a stator core designed to reduce iron loss. Summary of the invention

[0005] According to one aspect of the present application, a stator core is provided. The stator core may include: a main body composed of multiple layers of electromagnetic steel sheets stacked in layers, the main body being provided with at least a first through hole extending axially, a first pin located in the first through hole, a first end cover located at a first end of the main body connected to a first pin end of the first pin, and a second end cover located at a second end of the main body connected to a second pin end of the first pin, wherein the connection between the first end cover and the second end cover and the first pin generates tensile stress in the main body.

[0006] In one embodiment, the first through hole has a first inner surface close to the central axis of the stator core and a second inner surface away from the central axis, the first pin is spaced apart from the first inner surface, and the first pin contacts the second inner surface and generates thrust on the first inner surface.

[0007] In another embodiment, the first pin end of the first pin is connected to the first end cover by interference fit, and the second pin end of the first pin is integrated with the second end cover.

[0008] In yet another embodiment, the first pin end of the first pin and the first end cover, as well as the second pin end and the second end cover, are connected by interference fit.

[0009] In yet another embodiment, the first end cover has a first contact portion protruding from an inner surface of the first end cover to contact the first pin, and the second end cover has a second contact portion protruding from an inner surface of the second end cover to contact the first pin, the first contact portion and the second contact portion are configured to interfere with the first pin so that the first pin generates a thrust force on a portion of the inner surface of the first through hole, thereby generating tensile stress in a main magnetic flux area of ​​the stator core.

[0010] In yet another embodiment, the first end cover has a first contact portion protruding from an inner surface of the first end cover to contact the first pin, and the second end cover has a second contact portion protruding from an inner surface of the second end cover to contact the second pin; the inner surface of the first end cover has a first recess adjacent to the first contact portion to accommodate the first pin end, and a portion of the outer wall of the first contact portion forms an inner wall of the first recess; the inner surface of the second end cover has a second recess adjacent to the second contact portion to accommodate the second pin end, and a portion of the outer wall of the second contact portion forms an inner wall of the second recess; the first contact portion is configured to interfere with the first pin so that the first pin generates a thrust on a portion of the inner surface of the first through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

[0011] In another embodiment, the first pin end includes a first inclined surface facing the central axis, the first end cover has a first contact portion protruding from its inner surface and cooperating with the first inclined surface, the surface of the first contact portion opposite to the first inclined surface is an inclined surface, and the first contact portion and the first inclined surface interfere with each other so that the first pin generates a thrust on a portion of the inner surface of the first through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

[0012] In another embodiment, the first pin end includes a first inclined surface facing the central axis, the first end cover has a first contact portion protruding from its inner surface and cooperating with the first inclined surface, and the surface of the first contact portion opposite to the first inclined surface is an inclined surface; the second pin end includes a second inclined surface facing the central axis, the second end cover has a second contact portion protruding from its inner surface and cooperating with the second inclined surface, and the surface of the second contact portion opposite to the second inclined surface is an inclined surface; the interference fit between the first contact portion and the first inclined surface and the interference fit between the second contact portion and the second inclined surface enable the first pin to generate thrust on a portion of the inner surface of the first through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

[0013] In yet another embodiment, the first pin is made of a non-magnetic conductive material.

[0014] In yet another embodiment, the first through hole is disposed near the annular outer peripheral edge of the main body.

[0015] In yet another embodiment, the first through hole portion is located outside the annular outer peripheral edge of the main body portion.

[0016] In yet another embodiment, the stator core further includes a second pin, and the main body includes a second through hole for accommodating the second pin.

[0017] In yet another embodiment, the stator core further includes a second pin and a third pin, the main body further includes a corresponding second through hole and a third through hole, the first through hole, the second through hole, and the third through hole are evenly spaced apart from each other along the circumference, and the interference fit between the first end cover and the second end cover and the first pin, the second pin, and the third pin generates tensile stress along the through holes in the main magnetic flux area of ​​the stator core.

[0018] In yet another embodiment, the stator core further includes a second pin, a third pin, a fourth pin, a fifth pin and a sixth pin, the main body further includes a second through hole, a third through hole, a fourth through hole, a fifth through hole and a sixth through hole separated from each other, the first end cover and the second end cover include contact portions that cooperate with the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin, and the cooperation between the first end cover and the second end cover and the first pin, the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin generates thrust on the first through hole, the second through hole, the third through hole, the fourth through hole, the fifth through hole and the sixth through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

[0019] In another embodiment, the first through hole, the second through hole, the third through hole, the fourth through hole, the fifth through hole and the sixth through hole and the first pin, the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin have substantially the same structure, and the first through hole, the second through hole, the third through hole, the fourth through hole, the fifth through hole and the sixth through hole are evenly distributed along a circumference of the main body.

[0020] According to another aspect of the present application, a stator core is provided. The stator core may include: a main body composed of multiple layers of electromagnetic steel sheets stacked, the main body being provided with a first through hole and a second through hole extending axially; a first pin and a second pin arranged in the first through hole and the second through hole, the first pin and the second pin being used to connect the multiple layers of electromagnetic steel sheets as a whole; a first end cover located at the first end of the main body and contacting the first pin and the second pin, and a second end cover located at the second end of the main body and contacting the first pin and the second pin; the first pin and the second pin are interfered with by the first end cover and the second end cover to generate tensile stress in the main magnetic flux area of ​​the main body, a fixing member through hole axially penetrating the first end cover, the second end cover and the main body, and an axial fixing member extending through the fixing member through hole.

[0021] In one embodiment, the fixing member through hole is located outside the annular outer circumference of the main body.

[0022] In another embodiment, the main body includes an axially extending first lug and a second lug, the first lug and the second lug are at least partially located outside the outer circumference of the main body, the first through hole and the second through hole are at least partially located inside the first lug and the second lug, and the first end cover and the second end cover respectively have protrusions covering the first lug and the second lug.

[0023] According to another aspect of the present invention, a stator core is provided. The stator core may include: a main body composed of multiple layers of electromagnetic steel sheets stacked, the main body being provided with a first through hole, a second through hole and a third through hole extending axially; a first pin, a second pin and a third pin extending in the first through hole, the second through hole and the third through hole respectively; a first end cover located at the first end of the main body and contacting the first pin, the second pin and the third pin, and a second end cover located at the second end of the main body and contacting the first pin, the second pin and the third pin; the first pin, the second pin and the third pin are interfered with by the first end cover and the second end cover to generate tensile stress in the main magnetic flux area of ​​the main body, a fixing through hole axially penetrating the first end cover, the second end cover and the main body, and a fixing extending through the fixing through hole, the first pin, the second pin and the third pin, the first end cover and the second end cover and the fixing together form a connection structure connecting the multiple layers of electromagnetic steel sheets, wherein there are no welding points between the multiple layers of electromagnetic steel sheets.

[0024] In one embodiment, the first end cover includes a first contact portion, a second contact portion, and a third contact portion protruding from its inner surface, and the first contact portion, the second contact portion, and the third contact portion are in contact with the first pin ends of the first pin, the second pin, and the third pin, respectively; the second end cover includes a fourth contact portion, a fifth contact portion, and a sixth contact portion protruding from its inner surface, and the fourth contact portion, the fifth contact portion, and the sixth contact portion are in contact with the second pin ends of the first pin, the second pin, and the third pin, respectively.

[0025] In yet another embodiment, the direction of the tensile stress at the yoke generated by the cooperation of the first pin, the second pin and the third pin with the first end cover and the second end cover in the first through hole, the second through hole and the third through hole substantially coincides with the direction of the magnetic flux.

[0026] In yet another embodiment, the angle between at least a portion of the tensile stress direction and the magnetic flux direction is within 90 degrees.

[0027] In yet another embodiment, the angle between at least a portion of the tensile stress direction and the magnetic flux direction is within 45 degrees.

[0028] According to another aspect of the present application, a vehicle is provided, which includes a motor. The stator core of the motor may include: a main body composed of multiple layers of electromagnetic steel sheets stacked, the main body is provided with at least a first through hole extending axially, a first pin located in the first through hole, a first end cover located at a first end of the main body connected to a first pin end of the first pin, and a second end cover located at a second end of the main body connected to a second pin end of the first pin, wherein the connection between the first end cover and the second end cover and the first pin generates tensile stress in the main body.

[0029] The above advantages and other advantages and features of the present application will become apparent by reading the following detailed description alone or in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] For a more complete understanding of the embodiments of the present application, reference should be made to the embodiments illustrated in more detail in the accompanying drawings and described by way of example below, in which: 1A and 1B are schematic diagrams of stator structures in the prior art; Figure 2 This is a three-dimensional diagram of the stator core structure in the first embodiment of the present application; Figure 3A is a specific schematic diagram of the end cover and pin connection structure of the stator core in the first embodiment of the present application, Figure 3B Shows Figure 3A A magnified schematic diagram of the middle area B; Figure 4 is a schematic diagram of the connection between the end cover and the pin of the stator core in the second embodiment of the present application; Figure 5 is a schematic diagram of the connection between the end cover and the pin of the stator core in the third embodiment of the present application; Fig. 6A , 6B, 6C, and 6D are schematic diagrams of various exemplary structures of the end caps in one or more embodiments of the present application; Fig. 7A , 7B, 7C are schematic diagrams of various exemplary structures of pins of one or more embodiments of the present application; Figure 8 yes Figure 2 Schematic diagram of the tensile stress and magnetic field line distribution generated by the end cover and the pin in the embodiment shown. DETAILED DESCRIPTION

[0031] For the reference numerals in the accompanying drawings, the same or similar reference numerals are used to indicate the same or similar components. In the following description, multiple operating parameters and components are described in multiple embodiments. These specific parameters and components are included in this article only as examples and are not meant to be limiting.

[0032] As required, specific embodiments of the present application are disclosed in this specification; however, it should be understood that the disclosed embodiments are merely examples of the present application and may be implemented in a variety of alternative forms. The drawings need not be drawn to scale; some features may be enlarged or reduced to show the details of specific components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but only as a representative basis for teaching those skilled in the art to implement the present application in a variety of forms.

[0033] As mentioned in the background technology, electric motors are widely used, and improving the performance of electric motors is the focus of research. For stators, how to reduce iron loss is one aspect of performance improvement. The motor stator may generate compressive stress during the assembly process due to many reasons. For example, the traditional stator structure generates compressive stress during lamination, winding and assembly, and the compressive stress increases the iron loss of the electromagnetic steel sheet. The lamination method of the electromagnetic steel sheet generally adopts a buckle point structure plus an axial welding structure. The term buckle point structure can refer to a connection feature located on the electromagnetic steel sheet, or it can be an additional buckle that clamps two or more layers of electromagnetic steel sheets. However, both buckle points and welding points make the electromagnetic steel sheets conductive, which will further increase the iron loss. The inventors of the present application, in one or more embodiments, design a more effective stator fixing structure in order to solve one or more problems in the prior art.

[0034] Referring to Fig. 1A-Fig. 1B, Japanese patent publication JP2013062892 provides a rotating electric machine, specifically referring to the prior art of Fig. 1, wherein the patent discloses that the stator core 5 is formed by stacking laminated electromagnetic steel sheets 6, and the frame 3 on the periphery is used to install the stator core 5, and the rotor 8 located in the middle is concentrically arranged in the stator core 5. A gap 17 is formed between the outer periphery of the stator core 5 and the inner periphery of the frame 3, and the gap 17 is filled with an adhesive 19 to install the stator core 5 to the frame 3. In the motor 1, the stator core 5 is located in the frame 3, and the core 5 can be radially stretched away from the central axis at the position where the bolts are installed by the adhesive 19 and the radially arranged bolts 21. However, the circumferentially arranged bolts increase the radial size and the structure is complicated. The use of the adhesive increases the process.

[0035] Figure 2: is a three-dimensional diagram of the stator core 200 in the first embodiment of the present application. As shown in the figure, in the first embodiment, a stator core 200 is provided, which includes a columnar main body 210 having a first end 212 and a second end 214. In this embodiment, the main body 210 is formed by stacking and interconnecting multiple layers of electromagnetic steel sheets. The electromagnetic steel sheets can be silicon steel sheets or other suitable materials with similar electromagnetic properties. The stacked stator core main body 210 includes a yoke 216 that is generally annular and a tooth 218 surrounded by the yoke 216. Slots for winding are formed between adjacent teeth, and the winding fills each slot to form a stator winding. In addition, the main body 210 includes an axially extending opening or space 220 located in the center, that is, the main body 210 is a hollow cylinder. The opening 220 is used to accommodate the rotor. Depending on the motor design, the type and design of the rotor may be different. This application analyzes the stator structure design, so the rotor structure is not discussed here.

[0036] Reference Figure 2 and further references Figure 3A , Figure 3A yes Figure 2 FIG. 2 is a cross-sectional schematic diagram of a stator core 200 along the AA direction shown in the figure. The first end 212 of the stator body 210 is connected to the first end cover 230, and the second end 214 is connected to the second end cover 240. The connection method of the first end cover 230, the second end cover 240 and the body 210 will be explained in combination with other figures and embodiments.

[0037] Continue to refer Figure 2 and Figure 3A In the above-described embodiment, the yoke 216 is generally an annular cylinder, and the yoke 216 has a first end face 216a and a second end face 216b at the first end 212 and the second end 214, respectively. The first end cover 230 generally covers the first end face 216a of the yoke 216 of the main body 210, and the second end cover 240 generally covers the second end face 216b of the yoke 216. It is envisioned that the first end cover 230 may have a suitable size corresponding to the cross-section of the yoke 216, and may partially or completely cover the first and second end faces 216a, 216b of the yoke 216. In the described embodiment, the main body 210 further includes a plurality of lugs protruding along the periphery of the yoke 216, such as fastener lugs 211a, 211b, 211c, and pin connection lugs 213a, 213b, 213c, 213d, 213e, 213f. The fastener lugs 211 a , 211 b , 211 c may include through holes formed axially through the lugs and through which the fastener 100 may pass, so that the fastener may pass through and apply pressure to the body 210 in the axial direction. Figure 2The example fastener 100 in the embodiment is a bolt 102 and a nut 104. It should be understood that the fastener can be any suitable fastener. The pin connection lugs 213a, 213b, 213c, 213d, 213e, 213f can be used to set through holes and accommodate pins, and the connection between the end cap and the main body and the pins will be discussed in detail below.

[0038] Further, if Figure 2-3B As shown, the first end cover 230 (and / or the second end cover 240) may have a protrusion corresponding to the shape of the above-mentioned multiple lugs to cover the lugs. In the described embodiment, the fastener lugs 211a, 211b, 211c are generally located outside the outer circumference C of the main body to avoid possible adverse effects on the magnetic flux area of ​​the yoke. Figure 2 The figure shows three evenly distributed fastener lugs 211a, 211b, 211c and fastener holes, and it is understood that more or fewer fasteners can be provided as needed. In addition, although the fasteners shown in the figure are provided outside the circumference or outside the main magnetic flux area of ​​the yoke 216, depending on the shape of the motor core, the fasteners can also be provided close to the outer edge of the circumference, in other words, they can be partially provided on the outer circumference of the yoke. Figure 2 and Figure 3A-3B In the embodiment of the present invention, the pin connection lugs 213a, 213b, 213c, 213d, 213e, 213f are generally located outside the outer circumference of the main body. It should be understood that the main body may not include the pin connection lugs, and the through holes of the pins may also be arranged generally within the outer circumference C of the main body.

[0039] refer to Figure 3A In the described embodiment, the yoke portion 216 of the main body portion 210 may include a plurality of through holes that accommodate the pin connection structure. Figure 3A The yoke 216 is shown to include a first through hole 320 and a second through hole 321 and a first pin 330 and a second pin 340 respectively located in the first through hole 320 and the second through hole 321. The connection structure of the second pin 340 in the second through hole 321 is similar to that of the first pin 330 in the first through hole 320, and only the structure of the first through hole 320 and the first pin 330 is described in detail herein. Figure 3AThe schematic diagram shows a multi-layer stacked electromagnetic steel sheet 310. It is understood that the thickness is exaggerated for the purpose of illustration and does not represent the actual size. The main body 210 formed by stacking the multi-layer electromagnetic steel sheets 310 is provided with at least a first through hole 320 axially penetrating therethrough, and a first pin 330 axially extending in the first through hole 320. The first end 212 of the main body 210 is provided with a first end cover 230, and the second end 214 may be provided with a second end cover 240. The first pin 330 includes a first pin end 332 substantially located at or adjacent to the first end 212 of the main body 210, and a second pin end 334 located at or adjacent to the second end 214 of the main body 210. The connection between the first end cover 230 and the second end cover 240 and the first pin 330 generates tensile stress in the core main body 210, and its principle and test effect will be further explained in conjunction with the accompanying drawings.

[0040] Continue to refer Figure 3A In the described embodiment, the first pin end 332 of the first pin 330 and the first end cover 230, and the second pin end 334 and the second end cover 240 are connected by interference fit. Specifically, the first end cover 230 has an inner surface 231 facing the first end 212 and includes a first contact portion 232 at least partially protruding from the inner surface 231, and the second end cover 240 has an inner surface 241 facing the second end 214 and includes a second contact portion 242 at least partially protruding from the inner surface 241. The first pin end 332 and the second pin end 334 of the first pin 330 are in contact with the first contact portion 232 and the second contact portion 242, respectively. The first contact portion 232 and the second contact portion 242 may have any suitable structure, and the contact between the first pin 330 and the first contact portion 232 and the second contact portion 242 may be a suitable point, line, or surface contact. The first contact portion 232 and the second contact portion 242 are configured to interfere with the first pin end 332 and the second pin end 334 so that the first pin 330 generates a thrust F on the second inner surface 324 of the first through hole 320 p , the second inner surface 324 is a surface away from the central axis forming the first through hole 320. Thus, tensile stress is generated in the main magnetic flux area of ​​the stator core 310 or in the yoke 216. In the described example, the first and second pin ends 332, 334 have a first inclined surface 333 and a second inclined surface 335 facing the central axis X, the first contact portion 232 of the first end cover 230 contacts the first inclined surface 333 and generates compression, and the surface 233 of the first contact portion 232 opposite to the first inclined surface 333 can also be a corresponding inclined surface.

[0041] Figure 3B Shows Figure 3A The B area is an enlarged view of the interference fit between the first pin end 332, the first contact portion 232 and the first inclined surface 333. Figure 3BAs shown, the corresponding inclined surface 233 of the first contact portion 232 of the first end cap 230 contacts the first inclined surface 333 of the first pin, and the inclined surface may have a certain degree of roughness. In one or more embodiments, the end cap 230 and the main body 210 are fixed by the tightening force of the external fastener 100, such as the bolt 102 and the nut 104 described above, and the force applied by the fastener 100 at one or more points generates a component force F through the contact between one or more contact portions on the first end cap 230 and the inclined surface of one or more pins. L , F p .like Figure 3B As shown, the force F generated by the fastener 100 on the inclined surface 333 is shown, and the force F will generate an axial tightening force F as shown in the figure. L and thrust F p , thereby distributing the axial tightening force F around the stator L , and the radial thrust F p In other words, the end cap and the pin have a radial fixing effect on the multi-layer electromagnetic steel sheet 310, and thus can replace the connection of buckle points and welding points on the traditional stator. Thrust F p In the yoke 216 , radial tensile stress and tangential tensile stress are further generated in the material structure, thereby reducing iron loss.

[0042] Continue to refer Figure 3A and 3B In the described embodiment, the first through hole 320 has a first inner surface 322 relatively close to the central axis X of the stator core and a second inner surface 324 away from the central axis. The first inner surface 322 and the second inner surface 324 are not clearly distinguished by a boundary, and can have a suitable relatively flat or curved shape. Depending on the design, the first inner surface 322 and the second inner surface 324 can have relatively larger or smaller or the same size. The first pin 330 is spaced apart from the first inner surface 322, and the so-called spacing means that there is at least a partial gap 326 without contacting each other. The first pin 330 contacts the second inner surface 324 and generates a thrust F as shown in the figure on the second inner surface 324. p The pin 330 is restricted by the second inner surface, and further squeezes the second inner surface 34 to generate the above-mentioned thrust F p Thrust F p Further radial tensile stress and tangential tensile stress will be generated in the material structure.

[0043] In the above-described embodiment, the cross section of the first through hole 320 is generally rectangular. In other examples, the cross section of the first through hole is oblong. In still other examples, the cross section of the first through hole is circular. The first pin 330 may also have an adapted cross-sectional shape, and the contact between the first pin 330 and the second inner surface 324 may be point contact, line contact or surface contact. In order to apply force more evenly, it may be line or surface contact along the axial direction. As shown in reference Figure 3B As described, when the second inner surface 324 is subjected to the thrust F p After that, the material tissues are connected, so that tensile stress is generated around the first through hole 320, thereby generating tensile stress in the yoke 216 of the stator core, that is, the main magnetic flux area. A certain point of the material may include radial tensile stress and tangential tensile stress, so that the direction of the tensile stress may include multiple directions, at least part of the tensile stress direction is substantially consistent with the magnetic flux direction, and is distributed around the yoke.

[0044] Although in the above embodiment, the first pin end 332 and the second pin end 334 of the first pin 330 interfere with the at least partially protruding first contact portion 232 of the first end cover 230 and the at least partially protruding second contact portion 234 of the second end cover 240, it is conceivable that there are other suitable connection methods.

[0045] For example, Figure 4 A stator 400 according to another embodiment of the present invention is shown. Figure 3A-3B Similar to the embodiment of the present invention, at least a first through hole 420 axially extending therethrough is provided on the main body 410 formed by stacking electromagnetic steel sheets, and a first pin 430 axially extends in the first through hole 420. The first pin 430 includes a first pin end 432 located at the first end 412 of the main body 410, and a second pin end 434 located at the second end 414 of the main body 410. The connection between the first end cover 440 and the second end cover 450 and the first pin 430 generates tensile stress in the main body 410 of the core. Similarly, the first through hole 420 has a first inner surface 422 close to the central axis of the stator core and a second inner surface 424 away from the central axis, the first pin 430 is spaced apart from the first inner surface 422, and the first pin 430 contacts the second inner surface 424 and generates a thrust F as shown in the figure on the second inner surface 424. p The first end cap 440 and the second end cap 450 have a first contact portion 442 and a second contact portion 452 protruding from the inner surfaces 431 and 441 of the first and second end portions 412 and 414, respectively. Figure 3A-3BDifferent from the embodiment of the present invention, the first end cover 440 further includes a first recess 443 adjacent to the first end cover 440. The second end cover 450 and the second end cover 450 further include a second recess 453 adjacent to the first end cover 440 and the second end cover 450. A side wall of the first contact portion 442 forms a portion of the inner wall of the first recess 443. A side wall of the second contact portion 452 forms a portion of the inner wall of the second recess 453. The first contact portion 442 and the second contact portion 452 are configured to interfere with the first pin 430 so that the first pin 430 generates a thrust F on a portion of the inner surface of the first through hole 420, that is, the second inner surface 424. p , thereby generating tensile stress in the stator core. In this embodiment, the length of the first pin 430 may be slightly greater than the thickness of the stator core body 410 or the depth of the first through hole 420 .

[0046] One or more of the above embodiments describe a pin that is independent of the first and second end caps, but it is understood that the pin may also be preassembled with, or integrated with, one of the end caps. In other words, the first pin end and the second pin end are not necessarily as described above with reference to FIG. Figure 3A-3B And reference Figure 4 The described embodiments are independent of the first end cap and the second end cap, respectively.

[0047] refer to Figure 5 , Figure 5 A partial cross-sectional view of a stator 500 according to another embodiment of the present invention is shown, in which the first end cover 540 of the stator 500 is in an unmounted state. In one embodiment, the main body 510 of the stator core 500 has a first through hole 520 extending axially therethrough, and a first pin 530 extending axially through the first through hole 520. In the mounted state, the first pin end 532 of the first pin 530 is connected to the first end cover 540 by interference fit. The second pin end 534 of the first pin 530 is integrated with the second end cover 550. Similarly, the first through hole 520 has a first inner surface 522 close to the central axis of the stator core and a second inner surface 524 away from the central axis, and the first pin 530 is spaced apart from the first inner surface 522. In this embodiment, the second pin end 534 is integrated into the second end cover 550, and the first pin 530 is arranged at a position to interfere with or contact the second inner surface 524 of the first through hole 520 after installation. In other words, during installation, the second pin end 534 can be relatively pressed against the second inner surface 524 of the first through hole 520. In other examples, the first pin end 522 can be slightly inclined toward the central axis X to facilitate insertion into the first through hole 520, that is, the angle α shown in the figure can be slightly less than 90 degrees. When the first end cap 540 presses the first pin end 532, the first pin 530 can pass through the axial direction to generate a thrust on the second inner surface 524. Figure 3A-3B and Figure 4The difference of the embodiment shown is that the second pin end 520 of the first pin 530 is integrated with the second end cap 550 in this embodiment, and the installation is relatively convenient through appropriate size control. During installation, the integrated first pin 530 and the second end cap 550 are first inserted from one side so that the first pin 530 passes through the through hole 520, and then the first contact portion 542 of the first end cap 540 can be aligned with the first through hole and snapped with the first pin end 532 of the first pin 530 to complete the connection. Figure 5 The end cap with integrated pin on one side shown can also be used with the above-mentioned FIG3- Figure 4 The interference fit split pins in the first through hole and the second through hole different from the first through hole are combined with each other, and different pin end connection methods are respectively used in the first through hole and the second through hole different from the first through hole. For example, the second end cover 550 has an integrated first pin 530 and a second contact portion for inserting into the second through hole. The second pin is independent of the second end cover. The integrated first pin 530 can further play a positioning role.

[0048] refer to FIG. 6A to FIG. 6D And further reference Figures 2 to 5 In one or more embodiments, a plurality of through holes and a plurality of pins may be disposed around the yoke 216 of the stator core, and the matching is completed by the corresponding plurality of pin ends and the plurality of contact portions located at the end cover. FIG. 6A to FIG. 6D Only the top view and the side view of the first end cap are shown. It is understood that the second end cap may have a similar structure or the second end cap may be integrated with the pin. It is envisioned that the main body may have a through hole design corresponding to the arrangement and number of the multiple contact portions on the end cap.

[0049] Fig. 6AAn embodiment of a schematic diagram of a first end cap 630 is shown. In this example, the first end cap 630 has six protruding contact portions. The main body of the stator core may include first, second, third, fourth, fifth and sixth through holes spaced apart from each other for pin connection, and the stator core further includes first, second, third, fourth, fifth and sixth pins located in the first, second, third, fourth, fifth and sixth through holes. As described in the above example, the main body of the stator core may include through holes around its periphery for fasteners to pass through, which will not be described in detail for the sake of brevity. The first end cap 630 (and / or the second end cap not shown) may include contact portions 632a, 632b, 632c, 632d, 632e and 632f that cooperate with the first, second, third, fourth, fifth and sixth pins, wherein the protruding contact portions 632a, 632b, 632c, 632d, 632e and 632f are generally rectangular in cross section along the direction perpendicular to the axis. Accordingly, the plurality of through holes may have a substantially rectangular cross section. In other embodiments, the through holes may be in an elliptical, oblong or other suitable shape. The size of the through hole is slightly larger than the cross-sectional size of the protruding contact portions 632a, 632b, 632c, 632d, 632e, 632f and the pins to produce a gap. The cooperation of the first end cover 630 and / or the second end cover with the plurality of pins generates thrusts F1, F2, F3, F4, F5, and F6 on the partial inner surfaces of the plurality of through holes, thereby generating tensile stress in the yoke region or the "main magnetic flux region" of the stator core. For details, reference may be made to the above description of the first through hole and the first pin. The term "main magnetic flux region" may be understood here as the yoke region, that is, the annular region surrounding the tooth portion. It is understood that there may be more or fewer pins and through holes as needed. In this embodiment, it can be seen that the plurality of protrusions of the end cover are substantially evenly distributed, so that the generation of tensile stress is also relatively evenly distributed, but this is not necessary, and an optimized arrangement may be made according to the design. In one embodiment, the connection may be via two pins, which may be located generally at opposite positions.

[0050] In another embodiment, reference Figure 6B It can be seen that the end cap 640 is provided with three contact portions 642a, 642b, 642c which are substantially evenly distributed. Figure 6B In the example shown, the main body composed of the stacked multi-layer electromagnetic steel sheets can be provided with at least the first through hole, the second through hole, and the third through hole that penetrate axially, and the three through holes can be spaced 120 degrees apart, and the three pins can be spaced approximately 120 degrees apart from each other, so that the thrust and the tensile stress inside the corresponding material are generated and distributed more evenly. In addition, it can be understood that the shapes of the through holes and the contact parts, as well as the cross-sectional shape of the pins can be designed differently according to the needs. Fig. 6A and Figure 6BIn the embodiment shown, the multiple contact portions are arranged around the circumference of the end cover. It can be understood that in other embodiments, the multiple contact portions can be set at other suitable positions, such as similar to the setting of the fixing member through holes, at least partially outside the circumference.

[0051] refer to Figure 6C In another embodiment, it can be seen that three substantially evenly distributed elliptical contact portions 652a, 652b, and 652c are provided on the end cover 650 in this embodiment. A portion of each contact portion 652a, 652b, and 652c may be located outside the annular outer circumference of the end cover 650 or the entirety of the contact portion 652a, 652b, and 652c may be located outside the annular outer circumference of the end cover 650. Accordingly, a substantially elliptical through hole may be provided on the stator core, and the three pins 652a, 652b, and 652c may have a substantially circular or elliptical cross-section, and may be spaced approximately 120 degrees apart from each other. It is understood that fewer or more pins are also feasible.

[0052] refer to Fig.6D In another embodiment shown, the end cap 660 has two contact portions 662a and 662b. The cross-sections of the two contact portions 662a and 662b are circular. Part or all of each contact portion 662a, 662b is located outside the annular outer circumference of the end cap 650. In this example, the main body composed of the multi-layer electromagnetic steel sheets of the corresponding stacked structure can be provided with at least a first through hole and a second through hole that penetrate axially, and the first through hole and the second through hole can respectively include a first pin and a second pin extending therein, and the first pin and the second pin are used to connect the multi-layer electromagnetic steel sheets as a whole.

[0053] although Figures 6A to 6D One or more contact portions on the middle end cover are protruding, which can be understood and can also be used as described above. Figure 4 The connection is achieved by forming the end cap by being recessed from the inner surface of the end cap, and by providing a corresponding number of through holes on the stator, and by a corresponding number of pins passing through the through holes and partially extending out of the through holes.

[0054] In an embodiment of the present invention, the stator body may further include a fixing through hole axially penetrating the first and second end covers and the body, and an axial fixing extending through the fixing through hole. The stator as a whole is axially fixedly connected by the fixing. The axial force of the fixing is transmitted to one or more pins through the first and second ends and converted into a radial force in the body, thereby generating radial and tangential tensile stresses in the body (i.e., the electromagnetic steel sheet), which is beneficial to reduce the iron loss in the stator core. At the same time, the stator can realize the axial locking and connecting of the multi-layer electromagnetic steel sheets through the cooperation of one or more pins with the first end cover and the second end cover, that is, the pin plays the role of connecting and fixing the electromagnetic steel sheets, which is used to replace the fixing method of the weld points and buckle points between the multi-layer electromagnetic steel sheets. In one or more embodiments, the fixing through hole and the multiple through holes for accommodating the pins are at least partially placed outside the main magnetic flux area of ​​the circular outer periphery of the body and the first and second end covers.

[0055] The shape of one or more pins at the aforementioned or other positions of the present application can have a variety of suitable designs. In the above embodiments, substantially square and circular through holes are shown, and the pins matched therewith can have any suitable cross-section, such as square, circular, semicircular, etc., for example. FIG. 7A to FIG. 7C as displayed. Figures 7A to 7C The pin end with a bevel at one end is shown, and it can be understood that Figures 7A-7C Both ends of the pin in the diagram can have the same structure, or Figure 5 In the example shown, the other end of the pin is similarly integrated with the end cap on one side. As shown in the figure, the size of one or more through holes for accommodating the pin can be slightly larger than the cross section of the pin, so that when one or more pins are inserted and connected, a thrust can be generated on the side away from the central axis. Fig. 7A The outline of the through hole 730 located on the stator core and the cylindrical pin 732 located therein are simply shown. For the sake of simplicity, the end of the pin is not shown, and only the cross-section of the through hole 730 and the pin 732 is discussed here. The through hole 730 includes a first inner surface 722 adjacent to the center of the stator and a second inner surface 724 away from the center of the stator. Fig. 7A As shown, Fp represents the thrust generated by the contact between the pin 732 and the second inner surface 734 of the through hole 730, while the first inner surface 722 can remain in a non-contact state with the pin 732, such as the presence of a gap 738, to avoid extrusion and compressive stress on the yoke. In this example, the second inner surface 724 is a curved surface, and the thrust F is in a radial direction. The thrust F in multiple directions will then generate tensile stress in multiple directions in the material structure.

[0056] Figure 7BA circular through hole 740 and a pin 742 located therein are shown, wherein the through hole 740 includes a first inner surface 746 adjacent to the center of the stator and a second inner surface 744 away from the center of the stator. The pin 742 has a semicircular cross section, and similarly, the pin 742 generates thrust along the second inner surface 744, while the pin 742 is spaced apart from the first inner surface 746, that is, there is a gap 748. The thrust F p The direction is radiating, with thrust F in multiple directions p This will then generate tensile stress in multiple directions in the material structure.

[0057] refer to Figure 7C , showing a generally rectangular through hole 750 and a pin 752 of rectangular cross section. The through hole 750 includes a first inner surface 756 adjacent to the center of the stator and a second inner surface 754 away from the center of the stator. The pin 752 contacts and presses the second inner surface 754, and the pin 752 is separated from the first inner surface 756 by a gap 758. In this embodiment, the second inner surface 754 is generally a plane, so that the direction of the thrust Fp applied to the second inner surface 754 is generally consistent and perpendicular to the second inner surface 754. The above lists a plurality of specific embodiments of the cross-section of the pin and the shape of the hole, and it can be understood that there are other embodiments of the shape of the hole and the pin, as well as different ways of combining the pin and the hole.

[0058] refer to Figure 2 - Figure 7, as described above, it can be understood that the design of the first end cap and the second end cap can be changed as needed, and can be separated or integrated with the pin at one end, and the stator core can include a corresponding number of pins with suitable shapes, and their arrangement and distribution can have various changes. In one or more embodiments, a plurality of pins can be made of a material with low magnetic permeability, or the surface of the pins can be coated with a material with low magnetic permeability. The so-called low magnetic permeability can refer to a lower magnetic permeability than the material of the core itself, and the pin itself or the coating material can be, for example, but not limited to, stainless steel.

[0059] refer to Figure 8 , Figure 8 Schematic diagram of the tensile stress and magnetic field lines distribution generated by the end caps and pins in the embodiments of the present invention. The area shown by the loop is the magnetic flux area 816 or the yoke 816, and the loop 820 schematically represents the magnetic field lines. The tensile stress at the yoke generated by the cooperation of the pins with the first end cap and the second end cap in the through hole is represented by Fp. The arrows show the direction of the simulated tensile stress, such as radial tensile stress Fr and generally tangential tensile stress Ft, and tensile stresses in different directions are generated at various points in the material structure. In one or more of the above embodiments, the direction of the tensile stress at the yoke generated in the multiple through holes by the cooperation of multiple pins with the first end cap and the second end cap is at least partially substantially coincident with the direction of the magnetic flux, as shown in the figure, Ft substantially coincides with the magnetic field lines 820. In general, refer to Figure 8 The directions of the tensile stress Ft, Fr can be multiple radial directions as shown in the figure, but at least part of the tensile stress direction is substantially consistent with the direction of the magnetic field lines of the stator yoke as shown in the figure. In one embodiment, the direction of the tensile stress generated is at an angle with the magnetic flux direction, and the angle is within 90 degrees. In another embodiment, the angle between at least part of the tensile stress direction and the magnetic flux direction is within 45 degrees.

[0060] One or more embodiments of the present application provide a stator core, comprising: a main body composed of multiple layers of electromagnetic steel sheets stacked, the main body being provided with at least first and second through holes axially penetrating therethrough; a first pin and a second pin extending in the first and second through holes respectively, the first pin and the second pin being used to connect the multiple layers of electromagnetic steel sheets into one; a first end cover located at the first end of the main body in contact with the first pin and the second pin; and a second end cover located at the second end of the main body in contact with the first pin and the second pin; the first pin and the second pin are interfered with the first end cover and the second end cover to generate tensile stress in the main magnetic flux area of ​​the main body. The main body also includes a fixing through hole axially penetrating the first and second end covers and the main body, and an axial fixing extending through the fixing through hole. The axial connection of the multiple layers of electromagnetic steel sheets can be achieved by the cooperation of the first pin and the second pin with the first end cover and the second end cover, and tensile stress can be generated, thereby facilitating the reduction of iron loss in the stator core. In the described embodiment, the axial connection can be achieved without welding points and buckle points between the multiple layers of electromagnetic steel sheets, and without adhesives. By placing the fixing member through hole and the plurality of through holes for accommodating the pins at least partially outside the peripheral main magnetic flux area of ​​the main body and the first and second end caps, the adverse effect on the effective additional magnetic flux area can be minimized. Those skilled in the art can make various changes, modifications and variations to these specific embodiments without departing from the essence and scope defined by the claims of this application.

[0061] Certain combinations and subcombinations regarded as novel and non-obvious are particularly pointed out in the claims. These claims may refer to "an" element or a "first" element or similar features. Such claims should be understood to include one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the described features, functions, elements, and / or characteristics may be claimed by amendment of the present claims or by presentation in this or a related application. Such claims, whether broader, narrower, equivalent, or different than the original claims, should be deemed included in the subject matter of the present application.

Claims

1. A stator core, comprising: A main body composed of a plurality of stacked electromagnetic steel sheets, wherein the main body is provided with at least a first through hole extending axially, a first pin located in the first through hole, a first end cover located at the first end of the main body and connected to the first pin end of the first pin, and a second end cover located at the second end of the main body and connected to the second pin end of the first pin, The connection of the first end cap and the second end cap to the first pin generates tensile stress in the main body.

2. The stator core of claim 1, wherein the first through hole has a first inner surface close to a central axis of the stator core and a second inner surface away from the central axis, the first pin is spaced apart from the first inner surface, and the first pin contacts the second inner surface and generates thrust on the first inner surface. 3 . The stator core according to claim 1 , wherein the first pin end of the first pin is connected to the first end cover by interference fit, and wherein the second pin end of the first pin is integrated with the second end cover. 4 . The stator core according to claim 1 , wherein the first pin end of the first pin and the first end cover, as well as the second pin end and the second end cover are connected by interference fit.

5. The stator core of claim 1 , wherein the first end cover has a first contact portion protruding from an inner surface of the first end cover to contact the first pin, and the second end cover has a second contact portion protruding from an inner surface of the second end cover to contact the first pin, and the first contact portion and the second contact portion are configured to be interference-fitted with the first pin so that the first pin generates a thrust force on a portion of the inner surface of the first through hole, thereby generating tensile stress in a main magnetic flux area of ​​the stator core.

6. The stator core of claim 1, wherein the first end cover has a first contact portion protruding from an inner surface of the first end cover to contact the first pin, and the second end cover has a second contact portion protruding from an inner surface of the second end cover to contact the second pin; the inner surface of the first end cover has a first recess adjacent to the first contact portion to accommodate the first pin end, and a portion of the outer wall of the first contact portion forms an inner wall of the first recess; the inner surface of the second end cover has a second recess adjacent to the second contact portion to accommodate the second pin end, and a portion of the outer wall of the second contact portion forms an inner wall of the second recess; the first contact portion is configured to interfere with the first pin so that the first pin generates a thrust on a portion of the inner surface of the first through hole, thereby generating tensile stress in a main magnetic flux area of ​​the stator core.

7. The stator core of claim 1, wherein the first pin end includes a first inclined surface facing the central axis, the first end cover has a first contact portion protruding from its inner surface and mating with the first inclined surface, the surface of the first contact portion opposite to the first inclined surface is an inclined surface, and the first contact portion and the first inclined surface are interference-fitted so that the first pin generates a thrust on a portion of the inner surface of the first through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

8. The stator core of claim 1, wherein the first pin end includes a first inclined surface facing the central axis, the first end cover has a first contact portion protruding from its inner surface and cooperating with the first inclined surface, and the surface of the first contact portion opposite to the first inclined surface is an inclined surface; wherein the second pin end includes a second inclined surface facing the central axis, the second end cover has a second contact portion protruding from its inner surface and cooperating with the second inclined surface, and the surface of the second contact portion opposite to the second inclined surface is an inclined surface; the interference fit between the first contact portion and the first inclined surface and the interference fit between the second contact portion and the second inclined surface enable the first pin to generate a thrust on a portion of the inner surface of the first through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

9. The stator core of claim 1, wherein the first pin is formed of a non-magnetic conductive material.

10. The stator core of claim 1, wherein the first through hole is disposed near an annular outer peripheral edge of the main body portion.

11. The stator core of claim 1, wherein the first through hole portion is located outside an annular outer peripheral edge of the main body portion. 12 . The stator core of claim 1 , wherein the stator core further comprises a second pin and the body portion comprises a second through hole accommodating the second pin.

13. The stator core of claim 1, wherein the stator core further comprises a second pin and a third pin, the main body further comprises a corresponding second through hole and a third through hole, the first through hole, the second through hole and the third through hole are evenly spaced apart from each other along the circumference, and the interference fit between the first end cover and the second end cover and the first pin, the second pin and the third pin generates tensile stress along the through hole in the main magnetic flux area of ​​the stator core.

14. The stator core of claim 1, wherein the stator core further comprises a second pin, a third pin, a fourth pin, a fifth pin and a sixth pin, the main body further comprises a second through hole, a third through hole, a fourth through hole, a fifth through hole and a sixth through hole spaced apart from each other, the first end cover and the second end cover comprise contact portions cooperating with the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin, the first end cover and the second end cover cooperate with the first pin, the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin so as to generate thrust on the first through hole, the second through hole, the third through hole, the fourth through hole, the fifth through hole and the sixth through hole, thereby generating tensile stress in the main magnetic flux area of ​​the stator core.

15. The stator core of claim 14, wherein the first through hole, the second through hole, the third through hole, the fourth through hole, the fifth through hole and the sixth through hole and the first pin, the second pin, the third pin, the fourth pin, the fifth pin and the sixth pin have substantially the same structure, and the first through hole, the second through hole, the third through hole, the fourth through hole, the fifth through hole and the sixth through hole are evenly distributed along a circumference of the main body.

16. A stator core, comprising: A main body composed of a plurality of stacked electromagnetic steel sheets, wherein the main body is provided with a first through hole and a second through hole extending axially; A first pin and a second pin are arranged in the first through hole and the second through hole, and the first pin and the second pin are used to connect the multi-layer electromagnetic steel sheets into one body; a first end cap located at the first end of the main body and in contact with the first pin and the second pin, and a second end cap located at the second end of the main body and in contact with the first pin and the second pin; the first pin and the second pin interfere with the first end cap and the second end cap to generate tensile stress in the main magnetic flux area of ​​the main body, a fixing member through hole axially penetrating the first end cover, the second end cover and the main body, and An axial fixing member extends through the fixing member through hole.

17. The stator core of claim 16, wherein the fixing member through hole is located outside the annular outer circumference of the main body portion.

18. The stator core of claim 17, wherein the main body comprises a first lug and a second lug extending axially, the first lug and the second lug are at least partially located outside the outer circumference of the main body, the first through hole and the second through hole are at least partially located in the first lug and the second lug, and the first end cover and the second end cover respectively have protrusions covering the first lug and the second lug.

19. A stator core, comprising: A main body composed of a plurality of stacked electromagnetic steel sheets, wherein the main body is provided with a first through hole, a second through hole and a third through hole extending axially; a first pin, a second pin, and a third pin extending in the first through hole, the second through hole, and the third through hole, respectively; a first end cap located at the first end of the main body and in contact with the first pin, the second pin, and the third pin, and a second end cap located at the second end of the main body and in contact with the first pin, the second pin and the third pin; the first pin, the second pin and the third pin interfere with the first end cap and the second end cap to generate tensile stress in the main magnetic flux area of ​​the main body, a fixing member through hole axially penetrating the first end cover, the second end cover and the main body, and a fixing member extending through the fixing member through hole, The first pin, the second pin and the third pin, the first end cover and the second end cover and the fixing member together form a connection structure connecting the multiple layers of electromagnetic steel sheets, wherein there are no welding spots between the multiple layers of electromagnetic steel sheets.

20. The stator core of claim 19, wherein the first end cover comprises a first contact portion, a second contact portion, and a third contact portion protruding from an inner surface thereof, the first contact portion, the second contact portion, and the third contact portion respectively contact with the first pin ends of the first pin, the second pin, and the third pin; and the second end cover comprises a fourth contact portion, a fifth contact portion, and a sixth contact portion protruding from an inner surface thereof, the fourth contact portion, the fifth contact portion, and the sixth contact portion respectively contact with the second pin ends of the first pin, the second pin, and the third pin.

21. The stator core of claim 19, wherein the tensile stress direction at the yoke generated by the first pin, the second pin and the third pin cooperating with the first end cover and the second end cover in the first through hole, the second through hole and the third through hole substantially coincides with the direction of the magnetic flux.

22. The stator core of claim 19, wherein at least a portion of the tensile stress direction is within an angle of 90 degrees to the magnetic flux direction.

23. The stator core of claim 19, wherein at least a portion of the tensile stress direction is within an angle of 45 degrees to the magnetic flux direction.

24. A vehicle comprising a motor, wherein the stator core of the motor comprises: A main body composed of a plurality of stacked electromagnetic steel sheets, wherein the main body is provided with at least a first through hole extending axially, a first pin located in the first through hole, a first end cover located at the first end of the main body and connected to the first pin end of the first pin, and a second end cover located at the second end of the main body and connected to the second pin end of the first pin, The connection of the first end cap and the second end cap to the first pin generates tensile stress in the main body.

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