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KR-102962565-B1 - Method for Manufacturing Stator for Axial Gap Type Electric Motor

KR102962565B1KR 102962565 B1KR102962565 B1KR 102962565B1KR-102962565-B1

Abstract

The present invention relates to a method for manufacturing a stator for an axial gap type motor that can minimize core loss due to eddy currents by forming a divided tooth using a multi-stage stacked core formed by stacking a plurality of sub-stacked cores of different shapes. The method for manufacturing a stator for an axial gap type electric motor according to the present invention comprises the steps of: preparing a plurality of thin sheet metal pieces of a plurality of types by stamping them into a "T" shape from a thin electrical steel sheet, each having the same length but with a pair of flange portions that differ only in the lengths extended left and right from the leading edge; preparing a plurality of sub-laminated cores of different shapes by first laminating the plurality of thin sheet metal pieces according to type; preparing a plurality of split teeth by secondarily laminating the plurality of sub-laminated cores, each comprising a coil winding portion on which a coil is wound, an exposed plane disposed at the top of the coil winding portion, and a shoe having a pair of extended inclined surfaces formed by flanges extending from both sides of the exposed plane; forming a waterproof coating film made of a thin film thinner than a waterproof bulkhead on the exposed plane of the shoe of the plurality of split teeth; and forming the leading edge of each of the plurality of split teeth by an insert molding method so that it is embedded in the waterproof bulkhead when injection molding a body case.

Inventors

  • 김병수

Assignees

  • 주식회사 아모텍

Dates

Publication Date
20260508
Application Date
20240709

Claims (11)

  1. A method for manufacturing a stator for an axial gap type electric motor, wherein a rotor rotatably supported in a fluid flow passage of a pump housing and a stator disposed in a lower space for rotating and driving the rotor are separated by a waterproof bulkhead of a body case having an inverted cup shape, A step of preparing a plurality of thin steel plates by punching, each formed in a "T" shape from a thin electrical steel plate, each having a rectangular main body having a preset width and length, and a pair of flange sections extending perpendicularly to the left and right from both upper sides of the main body so as to gradually narrow in width; A step of preparing a plurality of segmented teeth having a coil winding section in which a coil is wound by stacking the plurality of thin iron plates, an exposed plane disposed at the top of the coil winding section, and a pair of extended inclined surfaces formed by extending the flange section to each side from the exposed plane; A step of forming a waterproof coating film on the exposed plane as a thin film thinner than the waterproof barrier; and When injection molding a body case having the above-mentioned waterproof bulkhead, the method includes the step of embedding the above-mentioned pair of extended inclined surfaces into the above-mentioned waterproof bulkhead using an insert molding method; A method for manufacturing an axial gap type stator for an electric motor, wherein the lower edge of each of the pair of flange portions of the above-mentioned thin sheet iron is extended perpendicularly from the main body, and the upper edge is formed by stamping so that the width of the flange portion gradually narrows.
  2. A method for manufacturing a stator for an axial gap type electric motor, wherein a rotor rotatably supported in a fluid flow passage of a pump housing and a stator disposed in a lower space for rotating and driving the rotor are separated by a waterproof bulkhead of a body case having an inverted cup shape, A step of preparing a plurality of thin steel plates by punching and forming them, each having a rectangular main body (411a) formed in a "T" shape from a thin electrical steel plate and each having a preset width and length, and a pair of flange portions extended perpendicularly to the left and right from each side of the upper part of the main body (411a) so that the width gradually narrows; A step of preparing a plurality of segmented teeth having a coil winding section in which a coil is wound by stacking the plurality of thin iron plates, an exposed plane disposed at the top of the coil winding section, and a pair of extended inclined surfaces formed by extending the flange section to each side from the exposed plane; and When injection molding a body case having the above-mentioned waterproof bulkhead, the method comprises the step of embedding the pair of extended inclined surfaces into the waterproof bulkhead using an insert molding method, while simultaneously forming a waterproof coating film extending from the waterproof bulkhead on the exposed surface, with a thin film thinner than that of the waterproof bulkhead. A method for manufacturing an axial gap type stator for an electric motor, wherein the lower edge of each of the pair of flange portions of the above-mentioned thin sheet iron is extended perpendicularly from the main body, and the upper edge is formed by stamping so that the width of the flange portion gradually narrows.
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  8. In paragraph 1 or 2, The above waterproof bulkhead is integrally formed in the center extending toward the lower space and has a support shaft receiving portion with a groove formed in the center, A method for manufacturing an axial gap type stator for an electric motor in which the plurality of split teeth are arranged annularly around the support shaft receiving portion and arranged parallel to the support shaft.
  9. In paragraph 1 or 2, After winding a coil on the coil winding body of each of the plurality of bobbins, the start line and end line of the coil are wound and fixed to the first and second alignment guide projections, and the leading ends of the start line and end line are extended downward; A step of assembling each of the plurality of bobbins, each having a coil wound on the coil winding portion of each of the plurality of split teeth; A step of connecting the assembly hole of the back yoke to the lower end of the coil winding portion protruding from the lower end of the bobbin, and then fixing the back yoke; and A method for manufacturing a stator for an axial gap type electric motor, further comprising the step of passing the leading ends of the start wire and end wire of the coil through a through hole for coil assembly of a printed circuit board (PCB) and then connecting them to a motor driving circuit.
  10. In Paragraph 9, The above plurality of bobbins each A coil winding body having a through hole formed in the center into which the coil winding portion of the split-type tooth is inserted, and a coil wound on the outer circumference; and The above body includes upper and lower flanges to define the area where the coil is to be wound at both ends, and The upper and lower flanges are formed in a hexagonal shape that narrows toward the center, and A shoe insertion part is formed around the opening of the body above, into which the bottom surface of the shoe of the split tooth is inserted, and A method for manufacturing an axial gap type stator for an electric motor, wherein the shoe of the split tooth is formed in a hexagonal shape and is formed smaller than the upper flange.
  11. In Paragraph 9, Each of the above plurality of thin iron plates is made of an electrical steel plate of S18, and The above-mentioned back yoke is a method for manufacturing a stator for an axial gap type electric motor made of S60 electrical steel sheet.

Description

Method for Manufacturing Stator for Axial Gap Type Electric Motor The present invention relates to an axial gap type motor for a water pump, and more specifically, to a method for manufacturing a stator for an axial gap type motor that can increase motor efficiency and reduce costs by minimizing core loss caused by eddy currents through the formation of a split tooth using a multi-stage laminated core formed by stacking multiple sub-laminated cores of different shapes in an axial gap type motor that is separated between a rotor and a stator using a waterproof partition. Generally, water pumps applied to vehicles are devices that function to circulate coolant. They are typically configured as engine-driven water pumps, which are forcibly driven by a belt to rotate a pump impeller and circulate coolant by sucking in and discharging it, with a seal unit assembled inside to prevent coolant leakage, and electric water pumps, which drive an electric motor using electricity provided by a battery or similar source, and circulate coolant by rotating an impeller through the electric motor to suck in and discharge it. Among them, the electric water pump mentioned above does not require the engine driving power of the vehicle compared to the engine-driven water pump, and thus has the advantage of increased engine efficiency and consequently improved fuel economy. Furthermore, it offers the advantage of being able to precisely control the temperature of the coolant, and is therefore being widely applied to various vehicle models recently. Among the above electric water pumps, the canned type electric water pump is a pump driven by an electric motor having a sealed container in the shape of a can inside the stator, and is structured such that a can structure is inserted between the rotor and the stator, and the hydraulic section is extended to the rotor section so that the rotor is submerged in cooling water, thereby allowing the incoming water to properly cool the frictional heat generated in the rotor. The aforementioned cand-type electric water pump typically features a structure where the magnet and stator core are positioned radially, allowing water to enter the magnet. Since a structure is required to prevent water from entering the stator (core winding section), it utilizes a waterproof structure employing a waterproof can or injection-molded parts. Consequently, the air gap between the rotor and the stator core increases, resulting in significant magnetic flux loss. Because this makes it difficult to meet the desired pump (motor) capacity with ordinary magnets, expensive rare-earth magnets are generally widely used. Generally, internal rotor motors are employed in water pumps (EWP), compressors, and oil pumps; however, since the magnetic cross-sectional area (i.e., effective area) of an inner rotor motor is small, the unit cost is high because performance is achieved using rare earth elements. Furthermore, water pump motors are inner rotor type motors, and since the rare-earth magnets (Nd-Fe-B) used in the rotor contain iron components, there is a problem with corrosion occurring when the magnets come into contact with water; therefore, the rotor section also adopts a waterproof structure. Consequently, water pump motors have a structure where the air gap between the rotor and the stator is large, making it inevitable to increase the amount of Nd used in the rotor magnets. However, employing a rotor with rare-earth magnets in this manner makes it impossible to avoid an increase in manufacturing costs for water pump motors. The primary reason for using non-rare-earth magnets instead of rare-earth magnets in electric motors is that they are relatively cheaper than rare-earth magnets. Accordingly, the design goal of the motor is to achieve magnetic energy equivalent to that of a motor using rare-earth magnets, even when utilizing inexpensive non-rare-earth magnets with lower magnetic force. Considering these points, the inventor proposed in Korean Published Patent Application No. 10-2021-0108844 (Patent Document 1) a water pump having magnetic energy equivalent to that of a motor using rare earth magnets, even when using low-cost ferrite magnets which are non-rare earth magnets, by reducing the air gap by completely separating the rotor and stator in an axial gap type motor using a waterproof partition made of thin plate. The axial gap type electric motor for a water pump (EWP) according to the above patent document 1 uses Soft Magnetic Composites (SMC) as a stator core, which is about three times more expensive than a laminated core and has the problem of reduced motor efficiency due to core loss caused by eddy currents. FIG. 1 is a perspective view of a water pump using an axial gap type electric motor according to one embodiment of the present invention. Figure 2 is a front view of the water pump shown in Figure 1. FIGS. 3a and FIGS. 3b are axial cross-sectional views of a water pump according to the present inve