Abstract: A gear ratio control unit is provided to set a target gear ratio on the basis of an operating condition of the vehicle. The gear ratio control unit controls a drive amount of a step motor such that an actual gear ratio converges with the target gear ratio, and when a deceleration of the vehicle exceeds a predetermined threshold, controls the gear ratio by controlling the drive amount of the step motor such that a predetermined gear ratio is maintained. The gear ratio control unit determines the predetermined threshold on the basis of the actual gear ratio upon detection of an operation of a brake.

Abstract: A control device for a vehicle continuously variable transmission comprises a shift control means for controlling either of or both the speed ratio at the continuously variable transmission mechanism and the gear position at the subtransmission mechanism so as to adjust an overall speed ratio to a final speed ratio and a torque capacity control means for controlling the torque capacity at a disengagement-side frictional engagement element in the subtransmission mechanism so as to sustain a torque capacity value substantially equal to zero in an inertia phase occurring during a process of adjusting the gear position at the subtransmission mechanism from the first gear position to the second gear position when a negative torque is input to the vehicle continuously variable transmission.

Abstract: A control device for a vehicle continuously variable transmission 4 includes: final speed ratio setting means for setting an overall speed ratio of the continuously variable transmission mechanism 20 and the subtransmission mechanism 30 to be reached on the basis of an operating condition of the vehicle as a final speed ratio; shift control means for controlling the continuously variable transmission mechanism 20 and the subtransmission mechanism 30 such that the overall speed ratio aligns with the final speed ratio at a predetermined transient response; stagnation determining means for determining whether or not a stagnation period in which the overall speed ratio stops varying will occur during an upshift; and reduction control means for shortening a time required to advance to an inertia phase from a start of a shift in the subtransmission mechanism 30 following a determination that the stagnation period will occur.

Abstract: A speed ratio of a continuously variable transmission mechanism 20 is increased when a speed ratio of a subtransmission mechanism 30 connected in series to the continuously variable transmission mechanism 20 is switched from a first speed to a second speed. When an excess rotation speed Nb obtained by subtracting a target rotation speed from an engine rotation speed Ne exceeds a determination value Nr1 during this shifting process, a rapid rotation increase in an internal combustion engine 1 is prevented by reducing a shift speed of the continuously variable transmission mechanism 20 (S105A).

Abstract: A subtransmission mechanism 30 comprises a Ravigneaux planetary gear mechanism 31, a Low brake 32 and a High clutch 33, shifts between a first speed gear position in which the Low brake 32 is engaged whereas the High clutch 33 is disengaged and a second speed gear position in which the Low brake 32 is disengaged and the High clutch 33 is engaged. A minute slip is caused at the Low brake 32 and then terminated by engaging the High clutch 33. A value representing the engaging state variation such as an engaging time period and/or an engaging speed of the High clutch 33 is learned and the pressure of oil supplied during the engaging operation of the High clutch 33 is corrected based upon the learned value, thereby assuring a smooth shift operation by compensating for any inconsistency in the torque transmission characteristics of the High clutch 33.

Abstract: A continuously variable transmission 4 for a vehicle includes a variator 20 that modifies a speed ratio continuously and a subtransmission mechanism 30 that is connected in series to the variator 20 and applies a first speed and a second speed, which is higher than the first speed, selectively. When the vehicle is running under a low load/high speed upshift condition having a lower load or a higher speed than a normal upshift condition, the subtransmission mechanism 30 is upshifted from the first speed to the second speed at a lower vehicle speed than under the normal upshift condition, and as a result, both rotation variation in an internal combustion engine 1 accompanying upshifting of the subtransmission mechanism 30 and an increase in a fuel consumption amount of the internal combustion engine 1 due to the shift operation in the continuously variable transmission 4 are suppressed.

Abstract: When a vehicle stops in a travel range, a transmission controller sets a subtransmission mechanism in a second speed interlocking condition in which a torque input into a continuously variable transmission is transmitted in a second gear position and both a frictional engagement element of a first gear position and a frictional engagement element of the second gear position are engaged, and when a predetermined condition is established while the vehicle is stationary, the transmission controller reduces an output shaft torque of the continuously variable transmission.

Abstract: A control device for a vehicle continuously variable transmission 4 comprises: inertia phase processing completing means for completing an instruction relating to inertia phase processing before an input rotation speed of the subtransmission mechanism 30 actually reaches an input rotation speed of the second gear position; and torque phase processing starting means for starting an instruction relating to torque phase processing, in which reception of an input torque of the subtransmission mechanism 30 is shifted from a disengagement side frictional engagement element to an engagement side frictional engagement element before the input rotation speed of the subtransmission mechanism 30 actually reaches the input rotation speed of the second gear position, after completing the instruction relating to the inertia phase processing.

Abstract: The transmission controller performs a non-coordinated shift, in which the gear position of the subtransmission mechanism is modified from the second gear position to the first gear position at a higher speed than when the gear position of the subtransmission mechanism is modified by a coordinated shift while permitting a deviation between the through speed ratio and the target through speed ratio, instead of the coordinated shift when it is determined that the second speed kick down shift is to be performed.

Abstract: A control device for a vehicle continuously variable transmission 4 comprises a shift control means for controlling either of or both the speed ratio at the continuously variable transmission mechanism 20 and the gear position at the subtransmission mechanism 30 so as to adjust an overall speed ratio to a final speed ratio and a torque capacity control means for controlling the torque capacity at a disengagement-side frictional engagement element in the subtransmission mechanism 30 so as to sustain a torque capacity value substantially equal to zero in an inertia phase occurring during a process of adjusting the gear position at the subtransmission mechanism 30 from the first gear position to the second gear position when a negative torque is input to the vehicle continuously variable transmission 4.

Abstract: A continuously variable transmission 4 for a vehicle includes a variator 20 that modifies a speed ratio continuously and a subtransmission mechanism 30 that is connected in series to the variator 20 and applies a first speed and a second speed, which is higher than the first speed, selectively. When the vehicle is running under a low load/high speed upshift condition having a lower load or a higher speed than a normal upshift condition, the subtransmission mechanism 30 is upshifted from the first speed to the second speed at a lower vehicle speed than under the normal upshift condition, and as a result, both rotation variation in an internal combustion engine 1 accompanying upshifting of the subtransmission mechanism 30 and an increase in a fuel consumption amount of the internal combustion engine 1 due to the shift operation in the continuously variable transmission 4 are suppressed.

Abstract: When a vehicle stops in a travel range, a transmission controller sets a subtransmission mechanism in a second speed interlocking condition in which a torque input into a continuously variable transmission is transmitted in a second gear position and both a frictional engagement element of a first gear position and a frictional engagement element of the second gear position are engaged, and when a predetermined condition is established while the vehicle is stationary, the transmission controller reduces an output shaft torque of the continuously variable transmission.

Abstract: A subtransmission mechanism 30 comprises a Ravigneaux planetary gear mechanism 31, a Low brake 32 and a High clutch 33, shifts between a first speed gear position in which the Low brake 32 is engaged whereas the High clutch 33 is disengaged and a second speed gear position in which the Low brake 32 is disengaged and the High clutch 33 is engaged. A minute slip is caused at the Low brake 32 and then terminated by engaging the High clutch 33. A value representing the engaging state variation such as an engaging time period and/or an engaging speed of the High clutch 33 is learned and the pressure of oil supplied during the engaging operation of the High clutch 33 is corrected based upon the learned value, thereby assuring a smooth shift operation by compensating for any inconsistency in the torque transmission characteristics of the High clutch 33.

Abstract: A control device for a vehicle continuously variable transmission 4 comprises: inertia phase processing completing means for completing an instruction relating to inertia phase processing before an input rotation speed of the subtransmission mechanism 30 actually reaches an input rotation speed of the second gear position; and torque phase processing starting means for starting an instruction relating to torque phase processing, in which reception of an input torque of the subtransmission mechanism 30 is shifted from a disengagement side frictional engagement element to an engagement side frictional engagement element before the input rotation speed of the subtransmission mechanism 30 actually reaches the input rotation speed of the second gear position, after completing the instruction relating to the inertia phase processing.

Abstract: A control device for a vehicle continuously variable transmission 4 includes: final speed ratio setting means for setting an overall speed ratio of the continuously variable transmission mechanism 20 and the subtransmission mechanism 30 to be reached on the basis of an operating condition of the vehicle as a final speed ratio; shift control means for controlling the continuously variable transmission mechanism 20 and the subtransmission mechanism 30 such that the overall speed ratio aligns with the final speed ratio at a predetermined transient response; stagnation determining means for determining whether or not a stagnation period in which the overall speed ratio stops varying will occur during an upshift; and reduction control means for shortening a time required to advance to an inertia phase from a start of a shift in the subtransmission mechanism 30 following a determination that the stagnation period will occur.

Abstract: A speed ratio of a continuously variable transmission mechanism 20 is increased when a speed ratio of a subtransmission mechanism 30 connected in series to the continuously variable transmission mechanism 20 is switched from a first speed to a second speed. When an excess rotation speed Nb obtained by subtracting a target rotation speed from an engine rotation speed Ne exceeds a determination value Nr1 during this shifting process, a rapid rotation increase in an internal combustion engine 1 is prevented by reducing a shift speed of the continuously variable transmission mechanism 20 (S105A).

Abstract: The transmission controller performs a non-coordinated shift, in which the gear position of the subtransmission mechanism is modified from the second gear position to the first gear position at a higher speed than when the gear position of the subtransmission mechanism is modified by a coordinated shift while permitting a deviation between the through speed ratio and the target through speed ratio, instead of the coordinated shift when it is determined that the second speed kick down shift is to be performed.

Abstract: A gear ratio control unit is provided to set a target gear ratio on the basis of an operating condition of the vehicle. The gear ratio control unit controls a drive amount of a step motor such that an actual gear ratio converges with the target gear ratio, and when a deceleration of the vehicle exceeds a predetermined threshold, controls the gear ratio by controlling the drive amount of the step motor such that a predetermined gear ratio is maintained. The gear ratio control unit determines the predetermined threshold on the basis of the actual gear ratio upon detection of an operation of a brake.