Low noise stator of an electric motor or generator and method of assembling the same

Abstract

A stator of an electric motor or generator comprises a core formed of ferromagnetic material having a plurality of teeth arranged circumferentially about an axis. In one aspect of the invention, at least one retaining member connects the end portions of at least two of the teeth to each other in a manner inhibiting relative movement between said tooth end portions. By inhibiting relative movement between said tooth end portions, vibration is reduced. Vibration can also be reduced by welding interior surfaces of a core to each other. Reducing the vibration reduces the noise emissions of the stator during operation.

1 . A stator of an electric motor or generator, the stator comprising:
 a core formed of ferromagnetic material, the core having a circular body and a plurality of teeth, the circular body defining a central axis, the axis defining radial and circumferential directions, the teeth being arranged circumferentially about the axis, each of the teeth extending radially from the circular body to a respective tooth end portion;   a plurality of windings, each of the windings extending around a respective one of the teeth in a manner such that the winding lies radially between the tooth end portion of the respective tooth and the circular body;   at least one retaining member, the retaining member connecting the tooth end portions of at least two of the teeth to each other in a manner inhibiting relative movement between said tooth end portions.   
     
     
         2 . A stator in accordance with  claim 1  wherein the at least one retaining member consists of a plurality of retaining members equal in number to the number of the teeth, and each of the retaining members connects the tooth end portions of a respective adjacent pair of the teeth. 
     
     
         3 . A stator in accordance with  claim 2  wherein each of the retaining members is generally rigid and is wedged between the tooth end portions of the respective adjacent pair of the teeth. 
     
     
         4 . A stator in accordance with  claim 3  wherein each of the retaining members and the respective pair of the teeth have interlocking geometry. 
     
     
         5 . A stator in accordance with  claim 4  wherein each of the retaining members comprises at least one resiliently deflectable tab that contributes to the interlocking geometry, and the resiliently deflectable tab is configured to resiliently deflect in a manner allowing the retaining member to be snap assembled to the respective pair of the teeth. 
     
     
         6 . A stator in accordance with  claim 1  wherein the at least one retaining member comprises a tension-type retaining member that inhibits the tooth end portions of the at least two of the teeth from moving away from each other. 
     
     
         7 . A stator in accordance with  claim 6  wherein the at least one tension-type retaining member comprises adhesive tape. 
     
     
         8 . A stator in accordance with  claim 6  wherein the at least one tension-type retaining member comprises at least one fiber. 
     
     
         9 . A method of assembling a stator of an electric motor or generator, the method comprising:
 attaching at least one retaining member to a core of the stator, the core being formed of ferromagnetic material and having a circular body and a plurality of teeth, the circular body defining a central axis, the axis defining radial and circumferential directions, the teeth being arranged circumferentially about the axis, each of the teeth extending radially from the circular body to a respective tooth end portion, the stator also comprising a plurality of windings, each of the windings extending around a respective one of the teeth in a manner such that the winding lies radially between the tooth end portion of the respective tooth and the circular body, the retaining member connecting the tooth end portions of at least two of the teeth to each other in a manner inhibiting relative movement between said tooth end portions.   
     
     
         10 . A method in accordance with  claim 9  wherein the at least one retaining member consists of a plurality of retaining members equal in number to the number of the teeth, and the method comprises attaching one of the retaining members between the tooth end portions of each respective adjacent pair of the teeth. 
     
     
         11 . A method in accordance with  claim 10  wherein each of the retaining members is formed of a material that is softer than the ferromagnetic material and each retaining member is press fitted into place during the step of attaching the retaining members to the core. 
     
     
         12 . A method in accordance with  claim 10  wherein each of the retaining members comprises at least one resiliently deflectable tab and the step of attaching the retaining members to the core comprises pressing each retaining member against the tooth end portions of the respective adjacent pair of the teeth in a manner causing the tab to initially resiliently deflect against one of the tooth end portions and thereafter to at least partially return to an undeflected state in a manner creating interlocking geometry between the retaining member and the tooth end portions of the respective adjacent pair of the teeth. 
     
     
         13 . A method in accordance with  claim 12  wherein each of the retaining members is formed of a material that is softer than the ferromagnetic material and each retaining member is press fitted into place during the step of attaching the retaining members to the core.