Patent attributes
The present invention provides a lock-up clutch mechanism for a torque converter, comprising a lock-up piston and a front cover having an engagement surface capable of being engaged with the lock-up piston and in which a friction material is stuck to wither one of the lock-up piston and the front cover and in which engagement and disengagement are performed in accordance with a hydraulic pressure difference between the front cover and the lock-up piston and wherein the friction material includes a first flat friction surface disposed at an outer diameter side and a second tapered friction surface disposed at an inner diameter side and further wherein, when the lock-up piston and the front cover are slip-controlled, the first friction surface is engaged with uniform face pressure, and, when the lock-up piston and the front cover are substantially integrally joined with a great hydraulic pressure difference under slip control, maximum face pressure is generated at a border between the first friction surface and the second friction surface.
