Electric power steering apparatus

• US 20020047460A1
• Filed: 03/27/2001
• Published: 04/25/2002
• Est. Priority Date: 03/27/2000
• Status: Abandoned Application

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Kurahashi, Hidenori, Shimizu, Yasuo, Yoneda, Atsuhiko, Asaumi, Hisao, Kuribayashi, Takashi
• Application Number:
  US09/818,138
• Publication Number:
  US 20020047460A1
• Time in Patent Office: Days
• US Class Current: 310/216
• CPC Class Codes: B62D 5/043 characterised by clutch means between driving element, e.g. motor, and driven element, e.g. steering column or steering gear
• CPC Class Codes: H02K 21/16 having annular armature cores with salient poles with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 7/1166 comprising worm and worm-wheel structural association with bearings specially adapted for worm gear drives H02K7/081

Abstract

An electric power steering apparatus is disclosed which includes an electric motor having less cogging to thereby provide a comfortable steering feel. The electric motor includes an annular outer stator and an inner rotor positioned within the outer stator. The outer stator has circumferentially arranged stator windings of nine or a multiple of nine poles. The inner rotor has circumferentially arranged permanent magnets of eight poles. The permanent magnets are radially magnetized, and have N and S poles alternately arranged circumferentially. Three or a multiple of three poles of the stator windings are connected in series and driven by three-phase electric power.

Claims

1. An electric power steering apparatus including an electric motor for applying a steering assist torque, corresponding to a steering torque, to a steering system, said electric motor comprising:

an annular outer stator having circumferentially arranged stator windings of nine or a multiple of nine poles; and

an inner rotor positioned within said outer stator and having circumferentially arranged permanent magnets of eight poles;

said stator windings being connected such that they can be driven by electric power of three phases.

2. An electric power steering apparatus according to claim 1, wherein said outer stator comprises nine or a multiple of nine salient poles radially arranged at an equal pitch, each of said salient poles having respective one of said stator windings wound therearound, three or a multiple of three poles of said stator windings being connected in series to provide three phases.

3. An electric power steering apparatus according to claim 2, wherein each of said three phases comprises those three or a multiple of three poles of said stator windings which are not positioned adjacent to each other, connected in series.

4. An electric power steering apparatus according to claim 2, wherein each of said three phases comprises those three or a multiple of three poles of said stator windings which are positioned adjacent to each other, connected in series.

5. An electric power steering apparatus according claim 1, wherein said eight poles of said permanent magnets are magnetized radially so that N and S poles are alternately arranged circumferentially.