Method of fabricating an injected molded motor assembly
First Claim
1. A method of producing an electrical motor comprising the steps of:
- constructing a rotor assembly on a rotor shaft, the rotor assembly having bearings disposed near the ends of the rotor shaft;
forming an intermediate stator assembly by assembling a stack of stator laminations having stator poles, insulating the stator poles, and wrapping the stator poles with stator windings;
placing the intermediate stator assembly into a mold fixture that includes an internal cavity shaped to define a rear end cap for the stator assembly and a mandrel projecting through the center of the intermediate stator assembly to form a central bore;
unitizing the stator assembly by injecting molten plastic under pressure into the mold fixture, whereby the molten plastic is forced into the intermediate stator assembly to encapsulate the stator windings, fill interior voids, and fill the mold cavity to form a unitary rear end cap;
cooling the assembly to solidify the molten plastic into a plastic mass, the plastic mass extending to and including the formed end cap, forming a continuous bore through the center of the molded stator assembly to accommodate the rotor assembly, the continuous bore also producing mounting surfaces for receiving the rotor assembly bearing; and
mounting the rotor assembly into the stator assembly by inserting the rotor assembly into the continuous bore and engaging the rotor bearings with the mounting surfaces.
3 Assignments
0 Petitions
Accused Products
Abstract
An electrical motor and the process for forming that motor utilizes injection molding techniques to unitize the stator assembly. The stator assembly includes a stator lamination stack and preferably a metal front end cap which is secured to the lamination stack after the lamination stack is insulated and wound. The windings are terminated at a plurality of conductive pins fusion welded to the terminating ends of the windings. The stator assembly with front end cap in place is positioned in an injection molding die. Pressure is applied to the die, and molten plastic is injected under pressure to fill voids in the stator assembly, and also to form a plastic mass which will serve as the rear end cap. The rear end cap is also molded with a connector portion which fixes the conductive pins in place as a part of the connector. A bore formed in the stator assembly provides mounting surfaces for bearings on a rotor assembly.
200 Citations
28 Claims
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1. A method of producing an electrical motor comprising the steps of:
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constructing a rotor assembly on a rotor shaft, the rotor assembly having bearings disposed near the ends of the rotor shaft; forming an intermediate stator assembly by assembling a stack of stator laminations having stator poles, insulating the stator poles, and wrapping the stator poles with stator windings; placing the intermediate stator assembly into a mold fixture that includes an internal cavity shaped to define a rear end cap for the stator assembly and a mandrel projecting through the center of the intermediate stator assembly to form a central bore; unitizing the stator assembly by injecting molten plastic under pressure into the mold fixture, whereby the molten plastic is forced into the intermediate stator assembly to encapsulate the stator windings, fill interior voids, and fill the mold cavity to form a unitary rear end cap; cooling the assembly to solidify the molten plastic into a plastic mass, the plastic mass extending to and including the formed end cap, forming a continuous bore through the center of the molded stator assembly to accommodate the rotor assembly, the continuous bore also producing mounting surfaces for receiving the rotor assembly bearing; and mounting the rotor assembly into the stator assembly by inserting the rotor assembly into the continuous bore and engaging the rotor bearings with the mounting surfaces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 27, 28)
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18. A method of producing an electrical motor comprising the steps of:
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constructing a rotor assembly on a rotor shaft, the rotor assembly having a central rotor adapted for support by bearings located near the ends of the rotor shaft; forming an intermediate stator assembly having stator poles and means for magnetizing the stator poles; placing the intermediate stator assembly into a mold fixture that includes an internal cavity shaped to define a rear end cap for the stator assembly and a mandrel projecting through the center of the intermediate stator assembly to form a central bore; unitizing the stator assembly by injecting molten plastic under pressure into the mold fixture, whereby the molten plastic is forced into the intermediate stator assembly to encapsulate the stator poles, fill interior voids, and fill the mold cavity to form a unitary rear end cap; cooling the assembly to solidify the molten plastic into a plastic mass, the plastic mass forming a central bore extending between the formed rear end cap and another end cap, the central bore being of a size adequate to closely receive the rotor of the rotor assembly; forming bearing support surfaces in the end caps, the bearing surfaces being sized to receive the bearings adapted to support the rotor; and mounting the rotor assembly into the stator assembly by inserting the rotor assembly into the continuous bore and engaging the rotor bearings with the mounting surfaces. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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Specification