Abstract: In a toroidal continuously variable transmission (TCVT) control apparatus with a variator unit and a ratio control hydraulic system, an electronic TCVT control unit electronically feedback-controls a transmission ratio based on a deviation from a desired transmission ratio, and generates a normal-period command signal to be input to a step motor for compensating for the deviation. The control unit determines whether the deviation can be compensated for by electronically feedback-controlling the transmission ratio based on the deviation and generates an abnormal-period command signal to be input to the step motor to realize a step-motor displacement capable of shifting or diverging the transmission ratio to a speed-reduction side, while keeping a trunnion out of contact with a stopper in the direction of the trunnion axis, when the deviation cannot be compensated for by electronically feedback-controlling the transmission ratio based on the deviation.

Abstract: A toroidal continuously-variable transmission shift control apparatus includes a controlling section to control an actual transmission ratio toward a target transmission ratio by producing a control command in one of a forward traveling control mode for a forward vehicle traveling state, and a reverse traveling control mode; and a control modifying section arranged to select one of the forward traveling control mode and the reverse traveling control mode in accordance with a first parameter representing a driver's intention. The control modifying section is configured to detect a change of the vehicle traveling direction in accordance with a second parameter which is the actual transmission ratio, and to modify the shift control of the toroidal continuously-variable transmission so as to shift the actual transmission ratio to a speed decreasing side upon detection of the change of the vehicle traveling direction.

Abstract: Enhanced ratio control in a toroidal drive of a T-CVT is provided. A factor of proportionality is computed by which a trunnion axial displacement and a T-CVT ratio rate are related. A filter in the form of a characteristic equation is established. This filter includes a physical quantity indicative of the T-CVT ratio and a physical quantity indicated by an actuator command, as inputs, a quasi-state quantity, as a state quantity, and a transition coefficient for the quasi-state quantity. The transition coefficient includes an observer gain. The quasi-state quantity is computed using the filter. An estimated quantity of a system state quantity of the T-CVT is computed using the quasi-state quantity, the observer gain, and a trunnion angular position. The system state quantity includes at least the first physical quantity. The observer gain is corrected in response to the factor of proportionality to keep the transition coefficient unaltered.

Abstract: Operating range of feedback in CVT ratio control has been extended by use of stabilized values as an actual value of CVT ratio. The actual value of CVT ratio is derived from first and second pulse train signals provided by input and output speed sensors. Updating of rotational speed of the input member is repeated at intervals governed by the first pulse train. Updating of rotational speed of the output member is repeated at intervals governed by the second pulse train. Updating of an old value of a ratio between the latest value of the rotational speed of the input member and the latest value of the rotational speed of the output member to a new value thereof is repeated each time immediately after the rotational speeds of the input and output members have been updated since the latest updating of an old value of the ratio.

Abstract: The trunnion (23) of a vehicle toroidal continuously variable transmission is displaced by a step motor (52) via a control valve (56) and oil pressure servo cylinder (50) in order to vary a speed ratio of the transmission. A controller (80) calculates a target value (z*) of a control variable (z) based on an accelerator pedal depression amount (APS) and output disk rotation speed (&ohgr;co) (S5). Further, a time-variant coefficient (f) showing the relation between the trunnion displacement (y) and variation rate ({dot over (&phgr;)}) of the gyration angle (&phgr;) of the power roller, is calculated (S10). The error between the speed change response of the transmission and a target linear characteristic can be decreased by determining a command value (u) to the step motor (52) under a control gain determined based on a time differential ({dot over (f)}) of the coefficient (f) (S20).

Abstract: A system for enhanced ratio control in a continuously variable transmission (CVT) includes a ratio control element positionable by an actuator in response to an actuator command to establish various CVT ratios in the CVT. At least one sensor generates a train of pulses indicative of speed of rotation of a predetermined rotary member of the CVT. A measured CVT ratio generator derives information of an actual CVT ratio out of at least the train of pulses to give a measured value of CVT ratio. A filter processes the measured value of CVT ratio in a manner to refine the information of the actual CVT ratio to give an estimated value of CVT ratio. A command generator determines the actuator command such that the actuator command remains unaltered when a deviation of the estimated value of CVT ratio from a desired value of CVT ratio stays within a dead zone.

Abstract: In an infinitely variable transmission, a continuously variable transmission (2) outputs the rotation of an input shaft (1) at an arbitrary speed ratio, and a fixed speed ratio transmission (3) outputs the rotation of the input shaft (1) at a fixed speed ratio. A planetary gear set (5) varies the rotation direction and speed of the output shaft (6) according to the difference of the output rotation speed of the fixed speed ratio transmission (2) and the output rotation speed of the continuously variable transmission (2). A sensor (81) which detects the rotation speed of the input shaft (1) and a sensor (82) which detects the output rotation speed of the continuously variable transmission (2) are provided, and a microprocessor (80) precisely calculates the rotation direction and rotation speed of the output shaft (6) from these rotation speeds.

Abstract: The trunnion (23) of a vehicle toroidal continuously variable transmission is displaced by a step motor (52) via a control valve (56) and oil pressure servo cylinder (50) in order to vary a speed ratio of the transmission. A controller (80) calculates a target value (z*) of a control variable (z)based on an accelerator pedal depression amount (APS) and output disk rotation speed (&ohgr;c0) (S5). Further, a time-variant coefficient (f) showing the relation between the trunnion displacement (y) and variation rate (&phgr;) of the gyration angle (&phgr;) of the power roller, is calculated (S10). The error between the speed change response of the transmission and a target linear characteristic can be decreased by determining a command value (u) to the step motor (52) under a control gain determined based on a time differential (f) of the coefficient (f) (S20).

Abstract: Enhanced ratio control in a toroidal drive of a T-CVT is provided. A factor of proportionality is computed by which a trunnion axial displacement and a T-CVT ratio rate are related. A filter in the form of a characteristic equation is established. This filter includes a physical quantity indicative of the T-CVT ratio and a physical quantity indicated by an actuator command, as inputs, a quasi-state quantity, as a state quantity, and a transition coefficient for the quasi-state quantity. The transition coefficient includes an observer gain. The quasi-state quantity is computed using the filter. An estimated quantity of a system state quantity of the T-CVT is computed using the quasi-state quantity, the observer gain, and a trunnion angular position. The system state quantity includes at least the first physical quantity. The observer gain is corrected in response to the factor of proportionality to keep the transition coefficient unaltered.

Abstract: In an infinitely variable transmission, a continuously variable transmission (2) outputs the rotation of an input shaft (1) at an arbitrary speed ratio, and a fixed speed ratio transmission (3) outputs the rotation of the input shaft (1) at a fixed speed ratio. A planetary gear set (5) varies the rotation direction and speed of the output shaft (6) according to the difference of the output rotation speed of the fixed speed ratio transmission (2) and the output rotation speed of the continuously variable transmission (2). A sensor (81) which detects the rotation speed of the input shaft (1) and a sensor (82) which detects the output rotation speed of the continuously variable transmission (2) are provided, and a microprocessor (80) precisely calculates the rotation direction and rotation speed of the output shaft (6) from these rotation speeds.