Lock-up torque converter with clutch piston engageable with converter cover

In a lock-up torque converter the combination of:

• an input member;
• a converter cover driven by said input member;
• a pump impeller secured to said converter cover and forming therewith a chamber;
• an output shaft;
• a turbine runner within said chamber connected to said output shaft;
• a clutch piston mounted within said chamber and drivingly connected to said turbine runner;
• said clutch piston being engageable with said converter cover to lock said turbine runner with said pump impeller and forming therewith a clutch chamber only when said clutch piston is in engagement with said converter cover;
• a converter housing surrounding said converter cover;
• a stationary sleeve fixed to said converter housing so as to surround part of said output shaft, said part of said output shaft having a uniform diameter;
• first, second and third plain non-perforate bushes disposed on said uniform diameter part of said output shaft at spaced intervals therealong for journalling it in said stationary sleeve member and defining between said output shaft and said stationary sleeve first and second closed annular chambers, said first chamber being defined between said first and second bushes and said second chamber being defines between said said second and third bushes, said first, second and third bushes having the same radial dimensions;
• said output shaft being formed with an elongate blind bore which fluidly communicates with said clutch chamber;
• said output shaft being also formed with a radial passage fluidly communicating said elongate bore with said second chamber;
• a lock-up valve;
• first passage means fluidly communicating said lock-up valve and said second chamber;
• second passage means for providing fluid communication with the inside of said pump impeller;
• and
• third passage means for providing fluid communication with the inside of said turbine runner, said third passage means including said first chamber and communicating with said second passage means for circulating fluid discharged from said turbine runner to said second passage means for reintroduction into said pump impeller.