Squirrel cage rotor with interference fit sleeve between shaft and core

Claim 2

A squirrel cage rotor for a dynamoelectric machine of the alternating current drive motor type, comprising: a rotatable shaft, a tubular shaft sleeve carried by said shaft including an inner diameter having a predetermined interference fit with said shaft, a laminated rotor core mounted on said sleeve including a series of winding slots and a center bore opening slidably receiving the outer diameter of said tubular shaft sleeve prior to assembly of the sleeve to said shaft, said tubular shaft sleeve being expanded radially outward against said bore opening by said interference fit thereby radially clamping said rotor core in driving relationship with said shaft, a squirrel cage winding including a plurality of conductor bars carried in said winding slots and a pair of conductive end rings interconnecting the ends of said conductor bars and extending axially from the ends of said rotor core, a pair of annular rotor end supports carried by said shaft sleeve at each end of said rotor core, means connected to said sleeve for applying axial forces to said end supports to clamp said rotor core between said end supports, said pair of annular rotor end supports including annulaR concave cavities conforming to the axially extending contours of said pair of conductive end rings and engaging the outer peripheries of said pair of conductive end rings for providing axial and radial support of said pair of conductive end rings, whereby said pair of conductive end rings are restrained from separating from the ends of said rotor core and said rotor core maintains a balanced condition during high speed operation.

Claim 3

A high speed squirrel cage rotor for a dynamoelectric machine of the alternating current drive motor type, comprising: a rotatable shaft, a tubular shaft sleeve carried by said shaft including an inner diameter having a predetermined interference fit with said shaft, a rotor core mounted on said tubular shaft sleeve including a stack of laminations made of a magnetic iron material and including a series of winding slots and a center bore opening slidably receiving the outer diameter of said tubular shaft sleeve prior to assembly of the sleeve to said shaft, said tubular shaft sleeve being expanded radially outward against said center bore opening by said interference fit for clamping said rotor core in driving relationship with said shaft thereby providing a radially compressive prestressed condition in said stack of laminations which is maintained at the maximum speeds of said shaft when opposing stresses are developed in the stack of laminations by centrifugal forces, a squirrel cage winding made of conductive material and including a plurality of conductors bars carried in said winding slots and a pair of conductive end rings integrally connected to the ends of said conductor bars and extending axially from the ends of said rotor core, a pair of annular rotor end supports carried by said tubular shaft sleeve at each end of said rotor core for maintaining said stator core in a fixed axial position, said pair of annular rotor end supports including annular concave cavities receiving said end rings so as to define annular lip portions engaging the outer peripheries of said pair of end rings and supporting the axial ends of said rotor core, said rotor end supports having a predetermined radially compressive prestressed condition and a predetermined cross sectional configuration whereby said lip portions control the radial deformation of said pair of end rings in a manner corresponding to radial deformation of said stack of laminations occurring with high speed operation of said shaft, and a pair of clamping members having internal threads engaging threads on said tubular sleeve for axially clamping said pair of annular rotor end supports to the ends of said rotor core and maintaining said stack of laminations in an axially compressed state.

Claim 4

A high speed squirrel cage rotor for a dynamoelectric machine of the alternating current drive motor type, comprising: a rotatable shaft, a tubular shaft sleeve carried by said shaft including an inner diameter having a predetermined interference fit with said shaft, a rotor core mounted on said tubular shaft sleeve including a stack of laminations made of a magnetic iron material and including a series of winding slots and a center bore opening slidably receiving the outer diameter of said tubular shaft sleeve prior to assembly of the sleeve to said shaft, said tubular shaft sleeve being expanded radially outward against said center bore opening by said interference fit for clamping said rotor core in driving relationship with said shaft thereby providing a radially compressive prestressed condition in said stack of laminations which is maintained at the maximum speeds of said shaft when opposing stresses are developed in the stack of laminations by centrifugal forces, a squirrel cage winding made of conductive material and including a plurality of conductors bars carried in said winding slots and a pair of conductive end rings integrally connected to the ends of said conductor bars and extending axially from the ends of said rotor core, a pair of annular rotor end supports carried by said tubular shaft sleeve at each end of said rotor core for maintaining said stator core in a fixed axial position, said pair of annular rotor end supports including annular concave cavities receiving said end rings so as to define annular lip portions engaging the outer peripheries of said pair of end rings and supporting the axial ends of said rotor core, said rotor end supports having a predetermined radially compressive prestressed condition and a predetermined cross sectional configuration whereby said lip portions control the radial deformation of said pair of end rings in a manner corresponding to radial deformation of said stack of laminations occurring with high speed operation of said shaft, and a pair of clamping members having internal threads engaging threads on said tubular sleeve for axially clamping said pair of annular rotor end supports to the ends of said rotor core and maintaining said stack of laminations in an axially compressed state.

Claim 5

A squirrel cage rotor for a dynamoelectric machine comprising: a rotor core formed of a plurality of laminations having a center bore defined by adjacent inner walls of said laminations, a tubular sleeve extending entirely through said center bore having an outer wall engaging the inner walls of said laminations, conductor means including conductive end rings carried by said rotor core, first and second end supports each having a first portion engaging end faces of said conductive end rings and a second portion located adjacent the outer periphery of said sleeve in alignment with an inner annular portion of said rotor core, means separate from said conductor means supporting said end supports such that said laminations are clamped between said end supports with said conductive rings disposed between said first portions of said end supports and with said inner annular portion of said rotor core disposed between said second portions of said end supports, and a rotatable shaft positioned within said sleeve having an outer wall engaging the inner wall of said sleeve, said shaft and sleeve having a predetermined interference fit such that said shaft and sleeve are tightly engaged and the outer wall of said sleeve tightly engages and applies a radial force to said inner walls of said laminations as said laminatioNs are held axially clamped by said end supports whereby an interference fit is provided between the outer wall of said sleeve and said inner walls of said laminations.

Claim 6

A squirrel cage rotor for a dynamoelectric machine comprising: a rotor core formed of a plurality of laminations having a center bore defined by adjacent inner walls of said laminations, a tubular sleeve extending entirely through said center bore having an outer wall engaging the inner walls of said laminations, conductor means including conductive end rings carried by said rotor core, first and second end supports each having a first portion engaging end faces of said conductive end rings and a second portion located adjacent the outer periphery of said sleeve in alignment with an inner annular portion of said rotor core, means separate from said conductor means supporting said end supports such that said laminations are clamped between said end supports with said conductive rings disposed between said first portions of said end supports and with said inner annular portion of said rotor core disposed between said second portions of said end supports, and a rotatable shaft positioned within said sleeve having an outer wall engaging the inner wall of said sleeve, said shaft and sleeve having a predetermined interference fit such that said shaft and sleeve are tightly engaged and the outer wall of said sleeve tightly engages and applies a radial force to said inner walls of said laminations as said laminatioNs are held axially clamped by said end supports whereby an interference fit is provided between the outer wall of said sleeve and said inner walls of said laminations.