Motor stator, manufacturing method thereof and motor

Abstract

The invention provides a motor stator, a manufacturing method thereof and a motor. In the motor stator, a stator core is provided with a plurality of slots distributed at intervals in the circumferential direction, and a stator winding is installed on the stator core and comprises a plurality of stranded wires and a plurality of single wires. Each stranded wire is inserted into the corresponding groove, the single wires are located outside the stator core, one end of at least one part of the single wires is electrically connected with one stranded wire, and the other end of at least one part of the single wires is electrically connected with the other stranded wire. Therefore, the plurality of stranded wires and the plurality of single wires form a predetermined electrical loop. Therefore, the conductor filling rate of the stator iron core can be improved, the utilization rate of the stator iron core is further improved, and the technical effect is more obvious especially under the condition that the grooves of the stator iron core are formed into other shapes of non-straight grooves. And moreover, the skin effect and the proximity effect can be weakened, so that the additional loss caused by the two effects is reduced.

Description

Technical Field

[0001] The present application relates to the field of electric motors, and in particular to a motor stator, a manufacturing method thereof, and a motor comprising the motor stator. Background Art

[0002] Nowadays, electric motors are widely used in pure electric vehicles and hybrid vehicles as a power source to drive the vehicles. The motor generally includes a motor stator and a motor rotor that can rotate relative to the motor stator. The motor stator includes a stator core and a stator winding assembled together. In the existing motor stator, a flat single wire with good conductivity and a rectangular cross-sectional shape is usually wound around the core as a conductor and forms a loop as needed to form a stator winding. During the assembly process of the motor stator, the above-mentioned conductor (such as a hairpin unit) with a specific shape needs to be inserted into the slot of the stator core, and then the two ends of the conductor need to be twisted and connected accordingly by, for example, welding. However, the above-mentioned conductors have a fixed width and height, and the slots of the stator core for inserting these conductors are correspondingly formed into straight slots that match the size and shape of the conductors, which may cause the following disadvantages:

[0003] i. The above scheme will limit the conductor filling rate of the stator core (laminated body), so that the utilization rate of the stator core is not high enough; and

[0004] ii. When the motor stator is powered by a high-frequency PWM signal, the AC current tends to flow along the outermost edge of the conductor, resulting in skin effect and proximity effect, leading to higher additional losses. Summary of the invention

[0005] In order to overcome or at least alleviate the deficiencies of the above-mentioned prior art, one object of the present application is to provide a new type of motor stator, which can improve the conductor filling rate of the stator core and thus improve the utilization rate of the stator core, and can correspondingly reduce the additional losses caused by the skin effect and the proximity effect. Another object of the present application is to provide a method for manufacturing the above-mentioned motor stator, which can simplify the manufacturing process of the motor stator and save corresponding costs. Another object of the present application is to provide a motor including the above-mentioned motor stator, the performance of which can be improved.

[0006] In order to achieve the above-mentioned invention objectives, this application adopts the following technical solutions.

[0007] The present application provides a motor stator as follows, comprising a stator core and a stator winding, wherein the stator core is formed with a plurality of slots distributed at intervals in the circumferential direction of the motor stator, and the stator winding is installed on the stator core, wherein the stator winding comprises:

[0008] a plurality of twisted wires, each of the twisted wires being inserted into a corresponding slot; and

[0009] A plurality of single wires are located outside the stator core, and one end of at least a portion of the single wires is electrically connected to one of the twisted wires and the other end is electrically connected to another twisted wire, thereby making the plurality of twisted wires and the plurality of single wires form a predetermined electrical circuit.

[0010] In an optional solution, the twisted wires in each of the slots are arranged in layers in the radial direction of the motor stator, and the two circumferential side surfaces of each of the twisted wires match the shape of the circumferential wall of the slot.

[0011] In another optional solution, one of the radially inner end and the radially outer end of the groove is closed and the other is open, and the groove is configured such that the width gradually decreases as it extends from the radially outer end toward the radially inner end.

[0012] In another optional solution, the cross-sectional shape of the twisted wire is an isosceles trapezoid.

[0013] In another optional solution, the motor stator includes a plurality of teeth for defining the slots, and the teeth are configured to have a constant width in the process of extending from the radial inner end toward the radial outer end.

[0014] In another optional solution, the plurality of twisted wires extend to both axial ends of the stator core or extend from the stator core toward both axial ends, and the stator winding further includes a connector for electrically connecting the single wire to the twisted wire, and the connector includes:

[0015] an insulating housing having a first interface and a second interface, the single wire is inserted into the first interface, and the twisted wire is inserted into the second interface; and

[0016] A conductive portion is disposed in the housing and connected to the single wire and the twisted wire, so that the single wire is electrically connected to the twisted wire.

[0017] In another optional solution, the conductive part includes a silver alloy, and the conductive part is connected to the single wire and the twisted wire by sintering a nano silver alloy.

[0018] In another optional solution, each of the single wires is a flat single wire with a rectangular cross-sectional shape, and at least a portion of the single wires is constructed to include:

[0019] A first arm, one end of which is electrically connected to one of the twisted wires;

[0020] a second arm, one end of which is electrically connected to another of the twisted wires; and

[0021] A connecting portion is connected to the other end of the first arm portion and the other end of the second arm portion.

[0022] The present application also provides a method for manufacturing a motor stator as described in any one of the above technical solutions, comprising:

[0023] an inserting step, wherein the stranded wires are inserted into corresponding slots of the stator core so that both ends of the stranded wires extend to both axial ends of the stator core or extend from both axial sides of the stator core; and

[0024] A connecting step, wherein both ends of each of the twisted wires are electrically connected to the corresponding single wires while the twisted wires are held in the grooves, so that the plurality of twisted wires and the plurality of single wires form a predetermined electrical circuit.

[0025] The present application also provides a motor as follows, comprising the motor stator described in any one of the above technical solutions.

[0026] By adopting the above technical solution, the present application provides a motor stator. In the above motor stator, a stator core and a stator winding are assembled together. The stator core is formed with a plurality of slots distributed at intervals in the circumferential direction. The stator winding is installed on the stator core and includes a plurality of twisted wires and a plurality of single wires. Each twisted wire is inserted into a corresponding slot, and a plurality of single wires are located outside the stator core. One end of at least a portion of the single wires (not necessarily each or all single wires in some cases) is electrically connected to a twisted wire and the other end is electrically connected to another twisted wire. Thus, the plurality of twisted wires and the plurality of single wires constitute a predetermined electrical circuit. In this way, on the one hand, when the portion of the stator winding located in the slot of the stator core is composed of a twisted wire, it is easy to make the shape of the portion of the stator winding be configured to be more matched with the shape of the slot, thereby improving the conductor filling rate of the stator core and thus improving the utilization rate of the stator core, especially when the slot of the stator core is formed into other shapes other than straight slots, the technical effect is more obvious. On the other hand, stranded wire is composed of multiple thin single wires twisted together and insulated from each other. When connected to high-frequency alternating current, the current distribution on each thin single wire is relatively uniform, thus weakening the skin effect and proximity effect at the same time, thereby reducing the additional losses caused by these two effects.

[0027] Furthermore, the present application provides a method for manufacturing the above-mentioned motor stator. The manufacturing method includes an insertion step and a connection step. In the insertion step, the stranded wire is inserted into the corresponding slot of the stator core so that the two ends of the stranded wire extend to the axial ends of the stator core or extend from the axial sides of the stator core. In the connection step, the two ends of each stranded wire are electrically connected to the corresponding single wire while the stranded wire is kept in the slot, so that a plurality of stranded wires and a plurality of single wires constitute a predetermined electrical circuit. In this way, compared with the existing motor stator that only uses flat single wires to form the motor winding, since there is no need to twist the ends of the stranded wires after inserting the stranded wires in the motor stator of the present application, the stranded wires can be electrically connected directly through the single wires located on the axial sides of the stator core to form a predetermined electrical circuit, thereby simplifying the manufacturing process of the motor stator and saving corresponding costs.

[0028] Furthermore, the present application also provides a motor including the above-mentioned motor stator. Since the motor stator according to the present application is adopted, the performance of the motor is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A is a three-dimensional schematic diagram showing a motor stator according to an embodiment of the present application.

[0030] Figure 1B It shows Figure 1A Schematic diagram of a longitudinal cross-section of a motor stator in which the section lines are omitted.

[0031] Figure 1C It shows Figure 1A Schematic diagram of the exploded view of the motor stator.

[0032] Figure 1D It shows Figure 1A Schematic diagram of a transverse cross-section of a motor stator in which the section lines are omitted.

[0033] Figure 1E It shows Figure 1D A partial enlarged schematic diagram of .

[0034] Figure 2A It shows Figure 1A A three-dimensional schematic diagram of the twisted wires of the stator winding of the motor stator.

[0035] Figure 2B It shows Figure 1A Schematic diagram of a single wire of the stator winding of an electric motor stator.

[0036] Figure 2C and Figure 2D It shows Figure 1A A three-dimensional schematic diagram of the connector of the stator winding of the motor stator.

[0037] Description of Reference Numerals

[0038] 1stator core; 1c slot; 11 yoke; 12 tooth;

[0039] 2 stator winding; 21 twisted wire; 22 single wire; 221 first arm; 222 second arm; 223 connecting part; 23 connector; 23o1 first interface; 23o2 second interface; 231 housing;

[0040] 3. Insulation paper;

[0041] A is axial; R is radial; C is circumferential. DETAILED DESCRIPTION

[0042] The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all feasible methods of the present application, nor to limit the scope of the present application.

[0043] In the present application, unless otherwise specified, “axial direction”, “radial direction” and “circumferential direction” refer to the axial direction, radial direction and circumferential direction of the stator (stator core) of the motor, respectively.

[0044] The structure of the motor stator according to the present application, especially the structure of the stator winding, is described below in conjunction with the drawings in the specification.

[0045] like Figures 1A to 1E As shown, the motor stator according to an embodiment of the present application includes a stator core 1, a stator winding 2 and an insulating paper 3 assembled together. The stator winding 2 is installed on the stator core 1, and the insulating paper 3 is arranged between the stator core 1 and the stator winding 2 to improve the insulation performance.

[0046] In this embodiment, if Figures 1A to 1E As shown, the stator core 1 can be formed into a laminated body by stacking silicon steel sheets in the axial direction A. The stator core 1 includes a yoke 11 and a plurality of tooth portions 12, the yoke 11 continuously extending along the entire circumference in the circumferential direction C, and the plurality of tooth portions 12 extending radially inward from the yoke 11. The plurality of tooth portions 12 are arranged spaced apart in the circumferential direction C, so that a plurality of slots 1c spaced apart and evenly distributed in the circumferential direction C are defined by the plurality of tooth portions 12. Specifically, a dovetail portion for mounting a slot wedge is provided at the radially inner end of the tooth portion 12, and the tooth portion 12 is constructed so that the width remains unchanged during the process of extending from the radially inner end to the radially outer end, thereby forming a so-called straight tooth structure. In addition, as Figure 1B As shown, both axial ends of the groove 1c are open toward the outside; Figure 1EAs shown, the radially outer end of the slot 1c is closed and the radially inner end is open, and the slot 1c is configured so that the width gradually decreases in the process of extending from the radially outer end to the radially inner end, so that the cross-sectional shape of the slot 1c is formed as an isosceles trapezoid as a whole, thereby forming a so-called skewed slot structure that is not a straight slot. In this way, the stator core 1 is formed into a structure with straight teeth and skewed slots, so that more conductors can be arranged in the slot 1c of the stator core 1, thereby improving the utilization rate of the stator core 1.

[0047] In this embodiment, if Figures 1A to 1E As shown, the stator winding 2 includes a plurality of twisted wires 21, a plurality of single wires 22, and a plurality of connectors 23 for electrically connecting the single wires 22 to the twisted wires 21. One end of a portion of the single wires 22 is electrically connected to one twisted wire 21 through one connector 23, and the other end is electrically connected to another twisted wire 21 through another connector 23, thereby making the plurality of twisted wires 21 and the plurality of single wires 22 form a predetermined electrical circuit via the plurality of connectors 23.

[0048] Each strand 21 extends linearly along the axial direction A, each strand 21 is inserted into a corresponding slot 1c, and both axial ends of each strand 21 extend out from the stator core 1 toward both axial sides. The strands 21 in each slot 1c are arranged in layers along the radial direction R of the stator. Figure 1E The layout of the layers of the stranded wires 21 in the slots 1c is shown in the figure. In the present embodiment, four layers are arranged along the radial direction R in each slot 1c, and each layer corresponds to a stranded wire 21. Furthermore, in order to improve the conductor filling rate of the stator core 1, the circumferential side surfaces of each stranded wire 21 match the shape of the circumferential wall of the slot 1c, and the contours of adjacent stranded wires 21 match so as to be tightly against each other. The cross-sectional shape of the stranded wire 21 is correspondingly formed into an isosceles trapezoidal shape, so that the multi-layer stranded wire 21 as a whole matches the shape of the slot 1c as much as possible, thereby being able to fill the corresponding slot 1c as much as possible, thereby improving the conductor filling rate of the stator core 1. As shown Figure 2A As shown, the twisted wire 21 can be formed by twisting together multiple single wires and covering them with an insulating layer (in an optional scheme, the twisted wire 21 can be formed by twisting together multiple single wires but does not have to be covered with an insulating layer). This construction is conducive to forming the twisted wire 21 into any shape that matches the shape of the slot 1c.

[0049] Each single wire 22 is a flat single wire having a rectangular cross-sectional shape. Figure 1A , Figure 1B and Figure 2BAs shown, a portion of the single wire 22 is configured as a card-isolating unit. The card-isolating unit includes a first arm portion 221, a second arm portion 222, and a connecting portion 223 that are formed as one body. The first arm portion 221 and the second arm portion 222 both extend linearly along the axial direction A, and the first arm portion 221 and the second arm portion 222 of the same card-isolating unit are connected to the twisted wires 21 located in different slots 1c. For example, one end of the first arm portion 221 is connected to the twisted wire 21 in one slot 1c, and one end of the second arm portion 222 is connected to the twisted wire 21 in another slot 1c. The connecting portion 223 is formed in a bent shape and its two ends are respectively connected to the other end of the first arm portion 221 and the other end of the second arm portion 222, and the size of the connecting portion 223 is configured to span the distance between the above-mentioned one slot 1c and the other slot 1c.

[0050] like Figure 2C and Figure 2D As shown, the connector 23 includes an insulating shell 231 and a conductive part assembled together. The insulating shell 231 has a first interface 23o1 and a second interface 23o2. The shape and size of the first interface 23o1 match the shape and size of the single wire 22, and the single wire 22 is inserted into the first interface 23o1. The shape and size of the second interface 23o2 match the shape and size of the twisted wire 21, and the twisted wire 21 is inserted into the second interface 23o2. The center lines of the two interfaces 23o1 and 23o2 of the same connector 23 can be located on the same straight line and parallel to the axial direction A. The conductive part is arranged in the shell 231. In this embodiment, the conductive part contains a silver alloy, and the conductive part is electrically connected to the single wire 22 and the twisted wire 21 by low-temperature sintering of nano silver alloy to connect to the single wire 22 and the twisted wire 21, so that the single wire 22 is electrically connected to the twisted wire 21.

[0051] A method for manufacturing a motor stator according to an embodiment of the present application is described below.

[0052] The manufacturing method includes an insertion step and a connection step. In the insertion step, the stranded wire 21 is inserted into the corresponding slot 1c of the stator core 1 so that the two ends of the stranded wire 21 extend from the axial sides of the stator core 1. In and after the insertion step, it is not necessary to twist the two ends of the stranded wire 21 as in the prior art. Furthermore, in the connection step after the insertion step, while the stranded wire 21 is maintained in the slot 1c, the two ends of each stranded wire 21 are electrically connected to the corresponding single wire 22 through the connector 23, so that the plurality of stranded wires 21 form a predetermined electrical circuit via the plurality of single wires 22. Specifically, the low-temperature sintering nano-silver alloy technology can be used to electrically connect the conductive part in the connector 23 to the stranded wire 21 and the single wire 22. After the twisted wire 21 and the single wire 22 are inserted into the corresponding interfaces 23o1 and 23o2 of the connector 23, the entire motor stator can be placed in a heating device and heated at a temperature of, for example, 150 degrees for 20 to 30 minutes, so that the atoms of the silver alloy material diffuse into the twisted wire 21 and the single wire 22 to form a dense crystal, thereby forming the twisted wire 21 and the single wire 22 into a solid whole through the conductive part. It can be understood that since the temperature required for sintering the nano silver alloy is relatively low, the heat generated during the processing can be greatly reduced, and the melting point of the conductive part after sintering will be greatly increased, so that the working requirements of the motor stator can be met. In this way, compared with the existing motor stator that only uses a single wire 22 to form a motor winding, since there is no need to twist the end of the twisted wire 21 after inserting the twisted wire 21 in the motor stator of the present application, the twisted wire 21 can be directly electrically connected through the single wire 22 to form a predetermined electrical circuit, thereby simplifying the manufacturing process of the motor stator and saving corresponding costs.

[0053] It should be understood that the above embodiments are merely exemplary and are not intended to limit the present application. Those skilled in the art may make various modifications and changes to the above embodiments under the guidance of the present application without departing from the scope of the present application. The following is a supplementary description of the technical solution of the present application.

[0054] i. The present application also provides a motor including the above-mentioned stator, which has all the technical effects of the motor stator of the present application, thereby improving the performance of the motor and providing greater torque and power with the same motor stator size. It can be understood that the present application solution can be applied to a motor with an outer stator and inner rotor layout, and can also be applied to a motor with an outer rotor and inner stator layout.

[0055] ii. In the above embodiment, the radial inner end of the slot 1c is open, but the present application is not limited thereto. In an optional solution, the radial outer end of the slot 1c of the stator core 1 is open and the radial inner end is closed, and the slot 1c is configured so that the width gradually increases in the process of extending from the radial inner end toward the radial outer end. In fact, the cross-sectional shape of the slot 1c is not limited to the isosceles trapezoidal shape described in the above embodiment, but can be adjusted to other shapes as needed.

[0056] iii. It can be understood that the number of layers of the twisted wires 21 arranged in a slot 1c is not limited to the number described in the above embodiment, and the number of layers of the twisted wires 21 in the slot 1c can be adjusted as needed, and the single wire 22 used to electrically connect different twisted wires 21 can use flat copper wire.

[0057] iv. In existing motors, the connection points of the motor windings are usually welded together by laser welding or argon arc welding, which requires special machines and processing methods, and generates a lot of heat during the processing, leading to thermal problems. In contrast, in the motor stator of the present application, the low-temperature sintering nano-silver alloy technology is used to electrically connect the conductive part in the connector 23 with the stranded wire 21 and the single wire 22. Since the temperature required for sintering the nano-silver alloy is relatively low, the heat generated during the processing can be greatly reduced, and the melting point of the conductive part after sintering will be greatly increased, thereby being able to meet the working requirements of the motor stator.

[0058] v. In an optional solution, the connector 23 may partially extend into the slot 1c. The twisted wire 21 may extend from the slot 1c or not. For example, a plurality of twisted wires 21 may be inserted into corresponding slots 1c and extend to both axial ends of the stator core 1.

[0059] vi. In an optional solution, the single line 22 can be directly constructed as follows Figure 1A The final shape shown, that is, after the twisted wire 21 and the single wire 22 are connected by the connector 23, there is no need to twist the single wire 22. In this way, the single wire 22 can be directly inserted into the connector 23 for welding.

[0060] It can be understood that only one end of some single wires 22 can be connected to the twisted wire 21, and the other end is used for electrical connection with other components of the motor.

Claims

1. A motor stator, comprising a stator core (1) and a stator winding (2), wherein the stator core (1) is formed with a plurality of slots (1c) spaced apart and distributed in a circumferential direction (C) of the motor stator, and the stator winding (2) is mounted on the stator core (1), characterized in that: The stator winding (2) comprises: a plurality of twisted wires (21), each of the twisted wires (21) being inserted into a corresponding slot (1c); and A plurality of single wires (22), the plurality of single wires (22) being located outside the stator core (1), one end of at least a portion of the single wires (22) being electrically connected to one of the twisted wires (21) and the other end being electrically connected to another of the twisted wires (21), thereby making the plurality of twisted wires (21) and the plurality of single wires (22) form a predetermined electrical circuit.

2. The motor stator according to claim 1, characterized in that: The twisted wires (21) in each slot (1c) are arranged in layers in the radial direction (R) of the motor stator, and the circumferential side surfaces of each twisted wire (21) match the shape of the circumferential wall of the slot (1c).

3. The motor stator according to claim 2, characterized in that: One of the radially inner end and the radially outer end of the groove (1c) is closed and the other is open, and the groove (1c) is configured such that the width gradually decreases as it extends from the radially outer end toward the radially inner end.

4. The motor stator according to claim 3, characterized in that: The cross-sectional shape of the twisted wire (21) is an isosceles trapezoid.

5. The motor stator according to claim 3, characterized in that: The motor stator comprises a plurality of teeth (12) for defining the slots (1c), and the teeth (12) are configured to have a constant width while extending from a radially inner end toward a radially outer end.

6. The motor stator according to any one of claims 1 to 5, characterized in that: The plurality of twisted wires (21) extend to both axial ends of the stator core (1) or extend from the stator core (1) toward both axial ends. The stator winding (2) further comprises a connector (23) for electrically connecting the single wire (22) to the twisted wire (21). The connector (23) comprises: An insulating housing (231) having a first interface (23o1) and a second interface (23o2), wherein the single wire (22) is inserted into the first interface (23o1) and the twisted wire (21) is inserted into the second interface (23o2); and A conductive part is arranged in the housing (231) and connected to the single wire (22) and the twisted wire (21), so that the single wire (22) is electrically connected to the twisted wire (21).

7. The motor stator according to claim 6, characterized in that: The conductive part comprises a silver alloy, and the conductive part is connected to the single wire (22) and the twisted wire (21) by sintering the nano silver alloy.

8. The motor stator according to any one of claims 1 to 5, characterized in that: Each of the single wires (22) is a flat single wire with a rectangular cross-sectional shape, and at least a portion of the single wires (22) is configured to include: A first arm (221), one end of which is electrically connected to one of the twisted wires (21); a second arm (222), one end of which is electrically connected to another of the twisted wires (21); and A connecting portion (223) connected to the other end of the first arm portion (221) and the other end of the second arm portion (222).

9. A method for manufacturing a motor stator according to any one of claims 1 to 8, characterized in that: include: an inserting step, wherein the stranded wire (21) is inserted into the corresponding slot (1c) of the stator core (1), so that both ends of the stranded wire (21) extend to both axial ends of the stator core (1) or protrude from both axial sides of the stator core (1); as well as A connecting step, wherein while the twisted wires (21) are maintained in the slots (1c), both ends of each of the twisted wires (21) are electrically connected to the corresponding single wires (22), thereby forming a predetermined electrical circuit with the plurality of twisted wires (21) and the plurality of single wires (22).

10. A motor, characterized in that: A motor stator comprising any one of claims 1 to 8.

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