Magnetic device with flux return strip

• US 6,455,973 B1
• Filed: 01/29/1999
• Issued: 09/24/2002
• Est. Priority Date: 01/29/1999
• Status: Expired due to Fees

• Current Assignee: Mannesmann VDO AG (Continental AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Christiaens, Alois, Loxsom, William, Ineson, David J.
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): Lam, Thanh
• Application Number:
  US09/240,135
• Time in Patent Office: 1,334 Days
• Field of Search: 310/190, 310/89, 310/216, 310/256, 310/259, 310/43, 310/258, 310/179, 310/254, 310/218, 310/112
• US Class Current: 310/190
• CPC Class Codes: H02K 1/145 having an annular coil, e.g. of the claw-pole type
• CPC Class Codes: H02K 5/10 with arrangements for protection from ingress, e.g. water or fingers
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132
• CPC Class Codes: H02K 7/06 Means for converting reciprocating motion into rotary motion or vice versa
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06

Abstract

A magnetic device having a stator assembly having a magnetic flux return path comprising at least a pair of pole plates located a fixed distance apart from each other and at least one flux return strip pressed between each pair of spaced apart pole plates, and a rotor assembly having permanent magnetic material and being disposed for rotation relative to the stator assembly. Use of the flux return strip eliminates the need for a housing of ferrous material to complete the flux return path and facilitates flexible design of light-weight non-metallic housings and mounting systems or integral mounting to mating components.

Claims

1. A magnetic device comprising:

a stator assembly having a magnetic flux return path comprising at least a pair of spaced apart pole plates located a fixed distance apart from each other and having a space therebetween and at least one flux return strip pressed entirely within the space between each pair of spaced apart pole plates; and

a rotor assembly having permanent magnetic material and being disposed for rotation relative to said stator assembly;

wherein each flux return strip has a cross-section having an arcuate center portion between a pair of relatively flat portions.

2. A magnetic device in accordance with claim 1, wherein said stator assembly further comprises at least two pair of pole plates with each pair of pole plates being held a fixed distance apart.

3. A magnetic device in accordance with claim 1, wherein said pole plates are over-molded into said stator assembly.

4. A magnetic device in accordance with claim 1, wherein the width of the cross-section of each flux return strip is increased when the strip is formed around the stator assembly.

5. A magnetic device in accordance with claim 1, wherein the device is an electric motor.

6. A magnetic device comprising:

a stator assembly having a magnetic flux return path including at least a pair of pole plates located a fixed distance apart from each other and at least one flux return strip, wherein at least a portion of the cross-section of the flux return strip is not flat and the width of the cross-section of the flux return strip is increased when the strip is formed around the stator assembly;

a rotor assembly having permanent magnetic material and being disposed for rotation relative to said stator assembly; and

wherein each flux return strip has a cross-section having an arcuate center portion between a pair of relatively flat portions.

7. A magnetic device in accordance with claim 6, wherein said stator assembly further comprises at least two pair of pole plates with each pair of pole plates being held a fixed distance apart.

8. A magnetic device in accordance with claim 6, wherein said pole plates are over-molded into said stator assembly.

9. A magnetic device in accordance with claim 6, wherein at least one flux return strip is pressed between each pair of spaced pole plates and is formed around said stator assembly.