Alternating current generator

• US 4,959,577 A
• Filed: 10/23/1989
• Issued: 09/25/1990
• Est. Priority Date: 10/23/1989
• Status: Expired due to Term

• Current Assignee: Remy Technologies LLC (BorgWarner Incorporated)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Radomski, Thomas A.
• Primary Examiner(s): Skudy, R.
• Application Number:
  US07/425,270
• Time in Patent Office: 337 Days
• Field of Search: 310/263, 310/258, 310/168, 310/156, 310/181, 310/212, 310/159, 310/232, 310/68 R, 310/68 D, 310/254, 322/28
• US Class Current: 310/263
• CPC Class Codes: H02K 21/044 Rotor of the claw pole type

Abstract

An alternating current generator for supplying the electrical loads on a motor vehicle. The generator has a stator core that carries a three-phase stator or output winding. The rotor of the generator has two claw pole members that are magnetically connected by a core. A field coil is disposed about the core. The pole fingers of the claw pole members are interleaved and a plurality of permanent magnets are secured to side surfaces of the pole fingers such that there is a permanent magnet between each pair of adjacent pole fingers. The generator is arranged such that flux developed by the permanent magnets can flow through a closed magnetic path that bypasses the air gap between the rotor and stator and such that energization of the field coil with unidirectional current cause permanent magnet flux to traverse the air gap between the rotor and stator and thereby provide a useful flux for generating voltage in the stator winding.

Claims

1. An alternating current generator comprising, frame means, a stator supported by said frame means comprising a stator core formed of magnet material that has slots, an output winding carried by said stator core including conductors disposed within said slots, a rotor supported by rotation by said frame means disposed within said stator core, said stator core and rotor being spaced to provide an air gap between said rotor and stator core, said rotor comprising a shaft, first and second claw-pole members formed of magnetic material carried by said shaft, said first claw-pole member having a plurality of first circumferentially spaced and axially extending pole fingers, said second claw-pole member having a plurality of second circumferentially spaced and axially extending pole fingers, said first and second claw-pole members being so oriented on said shaft that the pole fingers of said first and second claw-pole members are interleaved, a rotor core formed of magnetic material carried by said shaft interposed between said claw-pole members having opposite ends respectively engaging said claw-pole members, a field coil disposed about said rotor core, slip rings carried by said shaft electrically connected to opposite sides of said field coil, brushes engaging said slip rings adapted to be connected to a source of unidirectional current to energize said field coil, a plurality of permanent magnets respectively interposed between said first and second circumferentially spaced axially extending pole fingers, each permanent magnet having a first end face engaging a side surface of said circumferentially spaced axially extending first pole finger and a second opposite end face engaging a side surface of said circumferentially spaced axially extending second pole finger, said end faces of said permanent magnets having opposite magnetic polarities and said magnets being so oriented that magnet end faces of like magnetic polarity respectively engage opposed side surfaces of a given pole finger, said first and second claw-pole members and said rotor core member defining a closed magnetic circuit formed entirely of magnetic material that magnetically connects opposed end faces of all said permanent magnets, said magnetic circuit shunting said air gap between said rotor and stator core whereby the flux developed by said permanent magnets is diverted from said air gap by said magnetic circuit and only leakage flux developed by said permanent magnets traverses said stator core when said field coil is not energized, said field coil when energized with unidirectional current developing a field mmf in said magnetic circuit that is in such a direction as to oppose the mmf developed by said permanent magnets in said magnetic circuit whereby flux developed by said permanent magnets is caused to traverse said air gap through a path that includes adjacent first and second pole fingers, the flux developed by said field coil traversing said air gap and being applied to said stator core by said first and second pole fingers, the amount of permanent magnet flux applied to said stator core increasing as the unidirectional current applied to said field coil increases.

2. A voltage regulated alternating current generator comprising, frame means, said circumferentially spaced axially extending stator supported by said frame means comprising a stator core formed of magnetic material that has slots, an output winding carried by said stator core including conductors disposed within said slots, a rotor supported for rotation by said frame means disposed within said stator core, said stator core and rotor being spaced to provide an air gap between said rotor and stator core, said rotor comprising a shaft, first and second claw-pole members formed of magnetic material carried by said shaft, said first claw-pole member having a plurality of first circumferentially spaced and axially extending pole fingers, said second claw-pole member having a plurality of second circumferentially spaced and axially extending pole fingers, said first and second claw-pole members being so oriented on said shaft that the pole fingers of said first and second claw-pole members are interleaved, a rotor core formed of magnetic material carried by said shaft interposed between said claw-pole members having opposite ends respectively engaging said claw-pole members, a field coil disposed about said rotor core, slip rings carried by said shaft electrically connected to opposite sides of said field coil, brushes engaging said slip rings adapted to be connected to a source of unidirectional current to energize said field coil, a plurality of permanent magnets respectively interposed between said first and second pole fingers, each permanent magnet having a first end face engaging a side surface of a first pole and said circumferentially spaced axially extending a second opposite end face engaging a side surface of a second pole finger, said end faces of said permanent magnets having opposite magnetic polarities and said magnets being so oriented that magnet end faces of like magnetic polarity respectively engage opposed side surfaces of a given pole finger, said first and second claw-pole members and said rotor core member defining a closed magnetic circuit formed entirely of magnetic material that magnetically connects opposed end faces of all said permanent magnets, said magnetic circuit shunting said air gap between said rotor and stator core whereby the flux developed by said permanent magnets is diverted from said air gap by said magnetic circuit and only leakage flux developed by said permanent magnets traverses said stator core when said field coil is not energized, said field coil when energized with unidirectional current developing a field mmf in said magnetic circuit that is in such a direction as to oppose the mmf developed by said permanent magnets in said magnetic circuit whereby flux developed by said permanent magnets is caused to traverse said air gap through a path that includes adjacent first and second pole fingers, the flux developed by said field coil traversing said air gap and being applied to said stator core by said first and second pole fingers, the amount of permanent magnet flux applied to said stator core increasing as the unidirectional current applied to said field coil increases, and voltage regulating means for maintaining the output voltage of said generator at a desired regulated value, said regulating means applying direct field current to said field coil in only one direction through said field coil, said regulating means including means for varying the magnitude of said direct field current as an inverse function of the output voltage of the generator.