Reinforced magnet

• US 8,736,410 B2
• Filed: 09/22/2011
• Issued: 05/27/2014
• Est. Priority Date: 09/23/2010
• Status: Active Grant

• Current Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Original Assignee: Dyson Technology Limited (Beeswax Holdings UK Limited)
• Inventors: Jones, David Michael
• Primary Examiner(s): Rojas, Bernard
• Application Number:
  US13/240,676
• Publication Number:
  US 20120074806A1
• Time in Patent Office: 978 Days
• Field of Search: 335/296, 335/302, 310/44, 310/45, 310/46, 310/156.72, 310/156.01
• US Class Current: 335/302
• CPC Class Codes: H01F 41/02 for manufacturing cores, coils, or magnets H01F41/14 takes precedence; for dynamo-electric machines H02K15/00
• CPC Class Codes: H01F 41/0266 Moulding; Pressing H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11
• CPC Class Codes: H01F 7/0221 Mounting means for PM, supporting, coating, encapsulating PM
• CPC Class Codes: H02K 1/2733 Annular magnets
• CPC Class Codes: H02K 15/03 having permanent magnets
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

A magnet that includes a composite body and at least one reinforcing element. The reinforcing element is embedded within the body and increases the radial strength of the body. As a result, the magnet is able to rotate at higher speeds without fracturing. Additionally, methods of manufacturing the magnet are described.

Claims

1. A rotor comprising a shaft secured to a magnet, the magnet comprising a composite body having a bore, and at least one reinforcing element embedded within the body, wherein the shaft is secured within the bore, the body comprises a magnetic powder and a binder, the reinforcing element is embedded within the body by the binder, and the reinforcing element comprises a coil that surrounds the bore.

2. A rotor as claimed in claim 1, wherein the coil is thickest in a radial direction.

3. A rotor as claimed in claim 1, wherein the coil is adjacent the bore.

4. A rotor as claimed in claim 1, wherein the coil extends between opposite ends of the body.

5. A rotor as claimed in claim 1, wherein the coil is formed of a ribbon.

6. A rotor as claimed in claim 1, wherein the coil has a coefficient of thermal expansion no greater than twice that of the composite body.

7. A rotor comprising a shaft secured to a magnet, the magnet comprising a composite body having a bore and at least one reinforcing element embedded within the body, wherein the shaft is secured within the bore, the body comprises a magnetic powder and a binder, the reinforcing element is embedded within the body by the binder, the rotor has a rotational axis, and the reinforcing element comprises a coil that surrounds the rotational axis and has a radial stiffness and a radial tensile strength greater than that of the body.

8. A rotor comprising a shaft secured to a magnet, the magnet comprising a composite body having a bore, and a plurality of reinforcing elements embedded within the body, wherein the shaft is secured within the bore, the body comprises a magnetic powder and a binder, the reinforcing elements are embedded in the body by the binder and are spaced axially within the body, and each reinforcing element comprises a washer that surrounds the bore.

9. A rotor as claimed in claim 8, wherein each washer is thickest in a radial direction.

10. A rotor as claimed in claim 8, wherein each washer is adjacent the bore.

11. A rotor as claimed in claim 8, wherein each washer has a coefficient of thermal expansion no greater than twice that of the composite body.

12. A rotor comprising a shaft secured to a magnet, the magnet comprising a composite body having a bore, and a plurality of reinforcing elements embedded within the body, wherein the shaft is secured within the bore, the body comprises a magnetic powder and a binder, the reinforcing elements are embedded in the body by the binder, the rotor has a rotational axis, the reinforcing elements are spaced axially within the body, and each reinforcing element comprises a washer that surrounds the rotational axis and has a radial stiffness and a radial tensile strength greater than that of the body.