Brushless permanent magnet wheel motor with variable axial rotor/stator alignment

• US 7,042,128 B2
• Filed: 07/28/2005
• Issued: 05/09/2006
• Est. Priority Date: 11/14/2003
• Status: Active Grant

• Current Assignee: Dura-Trac Motors, Inc.
• Original Assignee: Dura-Trac Motors, Inc.
• Inventors: Zepp, Lawrence P., Medlin, Jerry W.
• Primary Examiner(s): Lam, Thanh
• Application Number:
  US11/192,351
• Publication Number:
  US 20060049712A1
• Time in Patent Office: 285 Days
• Field of Search: 310/75.C, 310 89- 91, 310111-118, 310/191, 310/254, 310/261
• US Class Current: 310/191
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/16 DC brushless machines
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2220/50 Structural details of electrical machines
• CPC Class Codes: H02K 11/21 Devices for sensing speed or position, or actuated thereby specially adapted for machines having non-mechanical commutating devices H02K29/06, H02K29/14
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 21/222 Flywheel magnetos
• CPC Class Codes: H02K 29/06 with position sensing devices H02K29/03 takes precedence
• CPC Class Codes: H02K 7/12 with auxiliary limited movement of stators, rotors or core parts, e.g. rotors axially movable for the purpose of clutching or braking
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

A brushless permanent magnet electric machine with a fixed radial air gap is operated to a much higher speed than normal maximum speed by the reduction in effective magnet pole strength. Permanent magnets are supported on the inner surface of an axially movable cylindrical shell. A plurality of magnetic poles provided with wire coils are supported on a stationary cylindrical member cooperate with the permanent magnets on the axially movable cylindrical shell to either cause, or react to, rotation of the axially movable cylindrical shell. The axially movable cylindrical shell and cylindrical member are coaxial. The cylindrical shell is axially movable with respect to the cylindrical member.

Claims

1. A brushless permanent magnet electrical machine which comprises:

a first cylindrical member having a central axis, an inner cylindrical surface and an outer cylindrical surface and a plurality of magnetic poles extending outward from the outer cylindrical surface of the first cylindrical member, the plurality of magnetic poles provided with wire coils around each of the plurality of magnetic poles;

a second cylindrical member having a central axis, an inner cylindrical surface and an outer cylindrical surface and a plurality of permanent magnets coupled to the inner cylindrical surface of the second cylindrical member, the second cylindrical member surrounding the first cylindrical member so that the plurality of magnet poles and the plurality of permanent magnets are adjacent and spaced apart from one another radially and the central axis of the second cylindrical member and the central axis of the first cylindrical member coincide and define a common central axis;

a rotatable shaft that is coaxial with the common axis; and

means for moving the second cylindrical member with respect to the first cylindrical member axially along the common central axis, which means for moving the second cylindrical member with respect to the first cylindrical member comprises a push rod that is coupled to an actuator.

2. A brushless permanent magnet electrical machine according to claim 1, wherein the push rod is coupled to the rotatable shaft through a thrust bearing.

3. A brushless permanent magnet electrical machine according to claim 1, wherein the actuator comprises a linear actuator.