Method for manufacturing a high speed squirrel cage rotor

Claim 1

A method of manufacture for a rotor of a dynamo-electric machine, the steps comprising: assembling a stack of laminations in axial alignment to form a rotor core having an axially extending center bore; slidingly fitting a tubular sleeve within said center bore to mount said rotor core on said tubular sleeve; axially clamping said stack of laminations between a pair of end supports in a fixed axial position relative to said tubular sleeve; and shrink fitting said tubular sleeve on a rotatable shaft having a predetermined interference fit with the inner diameter of said tubular sleeve to radially expand said tubular sleeve within said center bore thereby radially clamping said rotor core in driving relationship with said rotatable shaft with said stack of laminations being maintained in said fixed axial position by said pair of end supports.

Claim 2

A method of manufacture for a rotor of a dynamo-electric machine, the steps comprising: assembling a stack of laminations in axial alignment to form a rotor core having an axially extending center bore; slidingly fitting a tubular sleeve within said center bore to mount said rotor core on said tubular sleeve; axially clamping said stack of laminations between a pair of end supports in a fixed axial position relative to said tubular sleeve; and shrink fitting said tubular sleeve on a rotatable shaft having a predetermined interference fit with the inner diameter of said tubular sleeve to radially expand said tubular sleeve within said center bore thereby radially clamping said rotor core in driving relationship with said rotatable shaft with said stack of laminations being maintained in said fixed axial position by said pair of end supports.

Claim 3

A method for manufacture for a squirrel cage rotor of a dynamoelectric machine of the alternating current drive motor type, the steps comprising: assembling a stack of laminations in axial alignment to form a rotor core having a center bore opening and a plurality of winding slots forming conductor bars in said winding slots and a pair of conductive end rings extending axially from the ends of said rotor core to provide a squirrel cage winding; slidingly fitting a tubular sleeve into said center bore opening of said stack of laminations to mount said rotor core on said tubular sleeve; slidingly fitting a pair of annular rotor end supports over opposite ends of said sleeve and adjacent the ends of said rotor core, each of said rotor end supports being adapted to circumferentially enclose said pair of conductive end rings and axially support the of said stack of laminations; mounting a pair of clamping rings on opposite ends of said tubular sleeve and against said pair of annular rotor end supports; pressing said pair of clamping rings and said pair of rotor end supports against the ends of said rotor core whereby said stack of laminations is axially compressed; securing said pair of clamping rings in a fixed axial position on the ends of said tubular sleeve so that the axial compression of said stack of laminations is maintained by said pair of clamping rings; and shrink fitting said tubular sleeve to the shaft of said motor whereby said tubular sleeve is expanded radially outward by the shrink fitting therebetween so as to be clamped against said center bore opening of said rotor core and form a driving connection between said rotor core and said shaft.

Claim 4

A method for manufacture for a squirrel cage rotor of a dynamoelectric machine of the alternating current drive motor type, the steps comprising: assembling a stack of laminations in axial alignment to form a rotor core having a center bore opening and a plurality of winding slots forming conductor bars in said winding slots and a pair of conductive end rings extending axially from the ends of said rotor core to provide a squirrel cage winding; slidingly fitting a tubular sleeve into said center bore opening of said stack of laminations to mount said rotor core on said tubular sleeve; slidingly fitting a pair of annular rotor end supports over opposite ends of said sleeve and adjacent the ends of said rotor core, each of said rotor end supports being adapted to circumferentially enclose said pair of conductive end rings and axially support the of said stack of laminations; mounting a pair of clamping rings on opposite ends of said tubular sleeve and against said pair of annular rotor end supports; pressing said pair of clamping rings and said pair of rotor end supports against the ends of said rotor core whereby said stack of laminations is axially compressed; securing said pair of clamping rings in a fixed axial position on the ends of said tubular sleeve so that the axial compression of said stack of laminations is maintained by said pair of clamping rings; and shrink fitting said tubular sleeve to the shaft of said motor whereby said tubular sleeve is expanded radially outward by the shrink fitting therebetween so as to be clamped against said center bore opening of said rotor core and form a driving connection between said rotor core and said shaft.

Claim 5

A method for manufacture for assembling a squirrel cage rotor to the shaft of a dynamoelectric machine of the alternating current drive motor, the steps comprising: assembling a stock of laminations in axial alignment to form a rotor core having a center bore opening and a plurality of winding slots forming conductor bars in said winding slots and a pair of conductive end rings extending axially from the ends of said rotor core to provide a squirrel cage winding; slidably inserting a tubular shaft sleeve having externally threaded ends into said center bore opening to mount said rotor core on said tubular shaft sleeve, said sleeve including an inner diameter having a predetermined interference fit with the outer diameter of said shaft of said motor in the range of 0.011 to 0.014 inch; slidably mounting a pair of annular rotor end supports over opposite ends of said sleeve and adjacent the ends of said rotor core, each of said annular rotor end supports including an annular cavity having a cross-sectional configuration for receiving the inner and outer peripheries of said pair of conductive end rings; threading a pair of clamping rings on said threaded ends of said tubular shaft sleeve and against said pair of annular rotor end supports against the ends of said rotor core whereby said annular cavities receive said pair of end rings and said stack of laminations is provided with a predetermined axial compressive force across the ends thereof; terminating the threading of said pair of clamping rings so that said axial compressive force is maintained by said pair of clamping rings and said stack of laminations is maintained in a fixed axial position relative to said tubular shaft sleeve; and shrink fitting said tubular shaft sleeve to said shaft whereby said sleeve is expanded radially outward by said predetermined interference fit therebetween for radially clamping to said center bore opening of said rotor core in driving relationship with said shaft and developing predetermined radially compressive and tangential tensile prestresses in said stack of laminations and said pair of rotor end supports to reduce opposing alternating stresses developed in said stack of laminations by centrifugal forces when said shaft is rotated at high speeds.

Claim 6

A method for manufacture for assembling a squirrel cage rotor to the shaft of a dynamoelectric machine of the alternating current drive motor, the steps comprising: assembling a stock of laminations in axial alignment to form a rotor core having a center bore opening and a plurality of winding slots forming conductor bars in said winding slots and a pair of conductive end rings extending axially from the ends of said rotor core to provide a squirrel cage winding; slidably inserting a tubular shaft sleeve having externally threaded ends into said center bore opening to mount said rotor core on said tubular shaft sleeve, said sleeve including an inner diameter having a predetermined interference fit with the outer diameter of said shaft of said motor in the range of 0.011 to 0.014 inch; slidably mounting a pair of annular rotor end supports over opposite ends of said sleeve and adjacent the ends of said rotor core, each of said annular rotor end supports including an annular cavity having a cross-sectional configuration for receiving the inner and outer peripheries of said pair of conductive end rings; threading a pair of clamping rings on said threaded ends of said tubular shaft sleeve and against said pair of annular rotor end supports against the ends of said rotor core whereby said annular cavities receive said pair of end rings and said stack of laminations is provided with a predetermined axial compressive force across the ends thereof; terminating the threading of said pair of clamping rings so that said axial compressive force is maintained by said pair of clamping rings and said stack of laminations is maintained in a fixed axial position relative to said tubular shaft sleeve; and shrink fitting said tubular shaft sleeve to said shaft whereby said sleeve is expanded radially outward by said predetermined interference fit therebetween for radially clamping to said center bore opening of said rotor core in driving relationship with said shaft and developing predetermined radially compressive and tangential tensile prestresses in said stack of laminations and said pair of rotor end supports to reduce opposing alternating stresses developed in said stack of laminations by centrifugal forces when said shaft is rotated at high speeds.