Hydrokinetic torque converter for an automatic vehicle transmission

A hydrokinetic torque converter assembly for use with an engine in an automatic transmission in an automotive vehicle powertrain, the transmission having friction couplings with pressure-operated actuators, the converter assembly comprising:

• an impeller in a closed impeller housing;
• a turbine and a stator in the impeller housing, the turbine being connected drivably to a torque output turbine shaft;
• and
• a positive displacement pump having a pump drive member, the actuators being in controlled fluid pressure communication with the pump, the pump drive member having a central opening;
• the impeller including an impeller hub defined by an impeller sleeve shaft surrounding the turbine shaft;
• at least one internal flat in the central opening in the pump drive member and at least one external flat on the impeller sleeve shaft, the internal flat having a side surface in axial alignment with an end of the impeller sleeve shaft when the pump drive member surrounds the impeller sleeve shaft and the internal flat is out of registry with respect to the internal flat;
• the end of the impeller sleeve shaft being sloped from a first point on the impeller sleeve shaft end to a second point on the impeller sleeve shaft end, the second point being axially spaced relative to the first point;
• the side surface of the internal flat being engageable with the sloped end of the impeller sleeve shaft, whereby the internal flat moves relative to the impeller sleeve shaft toward engagement with the external flat as the impeller sleeve shaft enters the central opening of the pump drive member and whereby a driving connection is established between the impeller and the pump when the internal and external flats are in registry.