Heating oven for dynamo-electric machine component manufacture

Abstract

A heating oven for use in dynamo-electric machine component manufacture is provided. The oven uses forced air heating to raise the temperature of in-process component subassemblies to suitable process temperatures. The heating oven includes a rotating drum mounted in a cabinet. A number of open-ended tubular cradles are disposed in circular arrays between the drum faces. Batches of component subassemblies may be individually loaded into the cradles for heat treatment. Air flow channels are set up in the oven cabinet to evenly distribute heated air through individual cradles. Heated air after passing over the individual in-process subassemblies, exits the cradles through side slots in the cradle walls into the interior of the drum. The exiting air is reheated and recirculated through the heating oven.

Description

[0001] This application claims the benefit of U.S. provisional application No. 60 / 317,580 filed Sep. 5, 2001.BACKGROUND OF THE INVENTION [0002] The present invention relates to improved solutions for processing dynamo-electric machine components (e.g., armatures or stators for electric motors, generators, or alternators) through resin application process steps. [0003] Resin application steps are common in the manufacturing of dynamo-electric machine components. The dynamo-electric machine components such as armatures include insulated wire coils wound on ferromagnetic cores. Electric current passes through the wire coils in the operation of the dynamo-electric machine in which the component is used. For optimal performance of the dynamo, the dynamo-electric machine components' wire coils may be subject to tight dimensional tolerances. However, the wires in the coils, which are mechanically wound, are susceptible to loosening due to vibration or heat during further manufacturing or a...

AI Technical Summary

Benefits of technology

"The invention provides heating furnaces or ovens for heating dynamo-electric machine component subassemblies to an elevated temperature. These ovens can be integrated into manufacturing assembly lines by the use of suitable component holding transfer devices and conveyor apparatus. The heat treatment may involve preheating the subassemblies to condition them for resin application or inducing or accelerating resin curing. The ovens use forced air convection in the oven cabinet to provide a heated ambient in which the temperature of the in-process subassemblies is raised to suitable processing temperatures. The oven includes an enclosed processing cabinet with air-recirculating units to reheat the used air and recirculate it through the oven cabinet. The subassembly-holding cradles have inlet and outlet openings to allow air to flow into and out of them. The air flows through the cradles and the used air is collected and pulled out through the interior of the drum-like structure and the hollow axial shaft into the air-heating unit for reheating and recirculation. The invention provides a more uniform and reproducible heat treatment for batches of component subassemblies."

Problems solved by technology

However, the wires in the coils, which are mechanically wound, are susceptible to loosening due to vibration or heat during further manufacturing or assembly steps.

Operation of the dynamo-electric machine itself also may ause vibrations and heat, which tend to loosen the wire oils.

Electrical current, which passes through the wire oils, also may generate electromechanical forces that tend to loosen or deform the wire coil shapes.

Non-uniform temperatures across the impregnated resin on a dynamo-electric machine component may adversely affect the quality the hardened resin coating.

Further, component-to-component differences or variations in heating may adversely affect manufacturing process uniformity and reproducibility, which are desirable for commercial production.

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