Abstract: A torsional damper comprises first and second damper elements resiliently coupled by a spring arrangement, and a friction generating device. The friction generating device includes a plurality of friction blocks received in a plurality of windows, respectively, of the second damper element with play in the circumferential direction of the second damper element. The plurality of friction blocks are biased against a radially extending wall of the first damper element by a spring(s). For avoiding undesired interference engagement with the second damper element, the friction generating device includes a pair of axially opposed guide grooves for restricting radial mobility, with respect to an axis of rotation of the torsional damper, of the plurality of friction blocks.

Abstract: A torsional damper comprises damper elements which are resiliently coupled by a spring arrangement and a friction generating device. One of the damper elements has a radially extending wall. The friction generating device includes a plurality of friction blocks received by the other damper element with play in the circumferential direction, and a spring arranged to bias the plurality of friction blocks against the radially extending wall. In order to absorb the shock of engagement of each of the plurality of friction blocks with the other damper element, a cushion is provided.

Abstract: A clutch-slip control arrangement for a lock-up torque converter includes an orifice which is variable in opening in response to relative rotation or relative axial movement of a turbine hub and an output hub. In accordance with the present invention, a friction member is interposed between the turbine hub and the output hub for changing a performance characteristic of the orifice in such a manner that an orifice opening characteristic is different from an orifice closing characteristic.

Abstract: A clutch slip control device for a lock-up torque converter has a clutch slip control valve and an operating range detecting valve which are operative to control a lock-up control pressure in a lock-up control chamber based upon a torque pressure representative of a torque transmitted by a turbine runner and upon a governor pressure and a throttle pressure representative of a vehicle speed and an engine load.

Abstract: A slip control mechanism comprises a throttling path with a cross-sectional area variable according to the relative displacement of an output element of a torque converter and an output shaft. The throttling path is in communication via a fluid passage with a disengagement chamber opposing one side of a friction clutch. The other side of the friction clutch faces an engagement chamber. The disengagement chamber and the engagement chambers are so arranged as to control slippage of the friction clutch by pressure balance therebetween. The throttling path is formed in a specific geometry which assures moderate changes in the pressure balance between the disengagement chamber and engagement chamber in an intermediate throttling range. In the preferred construction, the throttling path is so constructed that the rate of change of the throttling cross-sectional area satisifes the inequalityd.sup.2 S/dx.sup.2 .gtoreq.

Abstract: A torque transmission through the hydrodynamic drive is directly measured by a torque sensor and a desired torque transmission is obtained for operating condition of a prime mover. The clutch slip of a lock-up clutch is adjusted toward a value where the measured torque transmission agrees with the desired torque transmission.

Abstract: In an automatic transmission for an automotive vehicle, an operating area covered by a high gear ratio is extended toward low vehicle speed side and the high gear ratio is released in response to the opening degree of the throttle and vehicle speed. The high gear ratio is released when the vehicle speed value is lower than a predetermined vehicle speed value and the opening degree of the throttle is larger than a predetermined opening degree.

Abstract: A torque converter having an engine-driven pump impeller fastened to an input shell and a fluid-driven turbine runner mounted on an output shaft is equipped with a fluid-operated lockup clutch for providing a direct mechanical drive between the input shell and the output shell. The lockup clutch is maintained in a slipping engagement condition in an intermediate speed range. This slipping engagement is controlled by a variable fluid passage whose opening size is determined by an axial position of the turbine runner relative to the output shaft. The turbine runner is rotatable and axially movable relative to the output shaft. The turbine runner and the output shaft have, respectively, flanges which rotates side by side. There are formed, between the flanges, a plurality of pockets which are circumferentially arranged. Each pocket has contoured surfaces, and confines a ball.

Abstract: A fuel cut-off control can prolong a period of time in which the engine speed is maintained at a range suitable for performing fuel cut-off and shorten a period of time in which the engine speed is in a fuel recovery range to minimize fuel consumption during engine deceleration. In a fuel cut-off control system in a fuel injection internal combustion engine with an automatic transmission, the fuel cut-off control system is responsive to a brake switch signal and an engine speed signal having a value above a fuel recovery threshold to decrease the value of a fuel cut-off threshold to again perform the fuel cut-off even in the normal fuel recovery range. Down shifting of a transmission gear is performed to increase engine speed to a level beyond the fuel cut-off threshold to prolong the fuel cut-off period.

Abstract: A lock-up control system is disclosed wherein the lock-up state of a torque converter is temporally released during gear shifting operation in an automatic transmission even if an automotive vehicle is operating in a predetermined lock-up range. A sensor generates an oil temperature compensation signal indicative of the temperature of oil used in the automatic transmission. The time duration of temporary release of the lock-up state is variable with variation in the oil temperature compensation signal.

Abstract: A lock-up control device in which a pulse train is generated which has a duration which increases as the vehicle speed decreases. A counter generates a period indicative signal indicative of a current period of the pulse train. A memory stores the period indicative signal for a preceding period. An adder generates an adder signal indicative of the addition of a preset value to the period indicative signal stored in the memory. A comparator compares the adder signal with the period indicative signal generated by the counter and generates a comparator signal when the former is larger than the latter. A flip-flop generates a flip-flop signal when the comparator signal occurs under the presence of a lock-up signal. An AND gate provides a lock-up release signal when said flip-flop signal occurs irrespective of the presence of the lock-up signal.