Coupling joints to interconnect and transmit rotational torque between adjacent impeller bodies in a turbomachine

A turbomachine having a rotor structure comprising:

• a tie bolt;
• a plurality of impeller bodies stacked adjacent to one another on the tie bolt;
• a respective coupling joint defined by respective adjacent impeller bodies of the plurality of impeller bodies to couple to one another the respective adjacent impeller bodies, the respective coupling joint defined by:
• a pair of corresponding axially engaging faces extending between a radially outer diameter and a radially inner diameter, wherein the radially outer diameter of the pair of corresponding axially engaging faces comprises a radially outermost diameter of the respective coupling joint;
• and
• a pair of corresponding radially engaging faces, one of the faces of the pair of corresponding radially engaging faces defined by an axial projection from one of the adjacent impeller bodies and the other one of the faces of the pair of corresponding radially engaging faces defined by an axially extending bore in the other one of the adjacent impeller bodies, the axially extending bore configured to receive the axial projection;
• and
• a torque transmitting arrangement further defined by the respective adjacent impeller bodies of the plurality of impeller bodies, the torque transmitting arrangement interposed between the pair of corresponding axially engaging faces and the pair of corresponding radially engaging faces,
• wherein the pair of corresponding axially engaging faces and the pair of corresponding radially engaging faces form a coupling pilot fit between the respective adjacent impeller bodies'
• wherein the torque transmitting arrangement comprises a plurality of circumferentially elongated tabs projecting from one of the adjacent impeller bodies and a plurality of apertures each respectively configured to receive a respective elongated tab of the plurality of circumferentially elongated tabs.