Cartridge style front cover and coupling cavity sleeve for automotive supercharger

A method of assembling a supercharger, comprising:

• providing a main housing including an outer wall structure having an interior surface defining overlapping cylindrical chambers housing a pair of intermeshed rotors, the main housing further defining a first inner wall structure disposed within an internal cavity defined by the outer wall structure and radially inward from the interior surface, the internal cavity being in fluid communication with the overlapping cylindrical chambers;
• inserting at least one rotor shaft into the internal cavity;
• providing a front cover separate from and coupled to the outer wall structure of the main housing, the front cover having an inner portion received within the internal cavity and an outer portion external to the main housing;
• inserting an input shaft through the front cover, wherein the input shaft extends through an internal passageway defined by the front cover inner and outer portions;
• inserting the front cover inner portion into the internal cavity such that the outer portion remains outside of the main housing;
• coupling the input shaft to the at least one rotor shaft for common rotation therewith;
• and
• disposing a non-rotating coupling sleeve over the coupling between the input shaft and the at least one rotor shaft of the pair of intermeshed rotors and entirely within the internal cavity, the coupling sleeve having a first end fixedly coupled to the first inner wall structure of the main housing and a second end fixedly coupled to the front cover inner portion that is received within the first inner wall structure of the main housing;
• wherein the coupling sleeve, the first inner wall structure, and the front cover define an isolator cavity that separates the input shaft and the coupling between the input shaft and the at least one rotor shaft within the internal cavity from the pair of intermeshed rotors within the overlapping cylindrical chambers.