Axial gap electrical machine

• US 9,124,165 B2
• Filed: 07/15/2013
• Issued: 09/01/2015
• Est. Priority Date: 11/14/2001
• Status: Expired due to Fees

• Current Assignee: Arjuna Indraeswaran Rajasingham
• Original Assignee: Arjuna Indraeswaran Rajasingham
• Inventors: Rajasingham, Arjuna Indraeswaran
• Primary Examiner(s): Lam, Thanh
• Application Number:
  US13/987,335
• Publication Number:
  US 20150015124A1
• Time in Patent Office: 778 Days
• Field of Search: 310 52- 59, 310/61, 310/114, 310/266, 310/268
• US Class Current: 1/1
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 21/24 with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• CPC Class Codes: H02K 3/02 Windings characterised by the conductor material
• CPC Class Codes: H02K 3/18 Windings for salient poles
• CPC Class Codes: H02K 5/18 with ribs or fins for improving heat transfer
• CPC Class Codes: H02K 9/227 Heat sinks

Abstract

An axial gap electrical machine employs unique architecture to (1) overcome critical limits in the air gap at high speeds, while maintaining high torque performance at low speeds, while synergistically providing a geometry that withstands meets critical force concentration within these machines, (2) provides arrangements for cooling said machines using either a Pelletier effect or air fins, (3) “windings” that are produced as ribbon or stampings or laminates, that may be in some cases be arranged to optimize conductor and magnetic core density within the machine. Arrangements are also proposed for mounting the machines as wheels of a vehicle, to provide ease of removing and installing said motor.

Claims

1. In an axial gap machine having a permanent magnet rotor and a stator comprising windings and working airgaps between said stators and rotors, such that movement of the magnets and their magnetic field relative to the windings in the stator generate an electromotive force across the windings and conversely such that when there is an electromotive force applied to the ends of the windings, the induced current in the windings and thereby in the magnetic field of the magnets in the rotor, create a force on the magnets of the rotor to cause its movement in a predetermined direction of rotation, said permanent magnet rotor further comprising a circular array of magnet structures comprising the magnet assembly, a means to cool the magnet assembly in the said permanent magnet rotor by arranging the magnet pole pairs around the periphery of the rotor, with radial gaps between them to allow airflow, said magnets being supporting on their outer radial periphery against centrifugal forces and minimal support elements between magnet assemblies to allow said airflow.

2. A permanent magnet rotor comprising magnet structures in a magnet assembly of an axial gap machine as in 1, wherein said radial gaps between said magnet structures are inclined to the orthogonal to the surface of the airgap such that on rotation of said rotor in said electrical machine, said radial airgaps act as air scoops to pump air from one side of the rotor to the other thereby contributing to forced air flow for cooling.

3. A permanent magnet rotor comprising magnet structures in a magnet assembly of an axial gap machine as in 1 wherein said “

radial”

gaps between said magnet structures are inclined such that their edges adjoining both the working air gap on either side are at an inclination to the orthogonal to the airgap such that on rotation of said rotor in said electrical machine, said radial airgaps act as air scoops to pump air from both sides adjoining the airgap on the periphery of the rotor for exhaust through ports in the housing of said machine thereby contributing to forced air flow for cooling of said magnet assembly.

4. A permanent magnet rotor comprising magnet structures in a magnet assembly of an axial gap machine as in 1, wherein said “

radial”

gaps between said magnet structures are slightly inclined such that their edges adjoining both the working air gap on either side are at an inclination to the orthogonal to the airgap such that on rotation of said rotor in said electrical machine, said radial airgaps act to suck air to both sides adjoining the airgap on the periphery with air sucked in from ports in the housing through the “

radial”

airgap to both sides of the rotor adjoining the working airgap, thereby contributing to forced air flow for cooling of said magnet assembly.

5. In an axial gap machine having a permanent magnet rotor and a stator comprising windings and a working airgaps between said stators and rotors, such that movement of the magnets and their magnetic field relative to the windings in the stator generate an electromotive force across the windings and conversely such that when there is an electromotive force applied to the ends of the windings, the induced current in the windings and thereby in the magnetic field of the magnets in the rotor, create a force on the magnets of the rotor to cause its movement in a predetermined direction of rotation, said permanent magnet rotor further comprising a circular array of magnet structures comprising the magnet assembly, a means to reduce eddy current losses in said magnet structures by composing each of said magnet structures with radial magnet elements bonded or pinned together such that each magnet structure has a plurality of magnet elements adjoining each other in a circumfrancial direction and having the same thickness in the axial direction at any radial distance from the axis.