Die-cast rotor housing for rotary combustion engines

Claim 1

A generally annular die-cast rotor housing shell for rotary internal combustion engines of the trochoidal type having a longitudinal axis and parallel side faces normal to the axis, the shell having an inner wall with a trochoidal inner surface and an outer wall spaced apart radially from the inner wall and having a plurality of generally axially oriented coolant passages therethrough between the inner and outer walls open at each side face and spaced circumferentially around the shell for flow of liquid coolant therethrough across the width of the shell in the generally axial direction, wherein the improvement comprises: at least some of the coolant passges having rectilinear individual axes slanted from each side wall angularly to the inner trochoidal surface and meeting at an angle at a position radially closer to the shell axis at the mid-plane between the shell faces so that the the inner wall of the shell is thinner at the midportion than at the side faces, the coolant passages having slanted axes comprising a plurality of groups of associated passages, each group of associated passages being circumferentially disposed along an arcutate portion of the generally annular shell, the associated passages of each group having their individual axes parallel to each other and nonparallel to the individual axes of the passages of other groups.