A calibration method for a slip control arrangement of a driveline including a continuously variable transmission is described herein. The driveline includes a clutch that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the clutch prevents the prime mover from stalling. A calibration method to link a valve command value and a torque allowed to pass through the clutch includes preventing the vehicle from moving and increasing the pressure applied in the clutch while noting the torque % value developed by the prime mover.

A control device for a lock-up clutch includes a control unit, an abnormality determination unit, a release control unit and a prohibition unit. The control unit is configured to control an engagement state of a lock-up clutch, and to perform a slip lock-up control by performing a feedback control of an engagement hydraulic pressure to be a first slip amount during coasting. The abnormality determination unit is configured to determine an abnormality when a state continues with a slip amount being equal to or greater than a second slip amount. The release control unit is configured to release the lock-up clutch when the abnormality is determined. The prohibition unit is configured to allow the control unit to raise the engagement hydraulic pressure by a prescribed pressure, and to prohibit determination by the abnormality determination unit, when the transmission ratio is downshifted during coasting while the slip lock-up control is performed.

A control device for a lock-up clutch includes a control unit, an abnormality determination unit, a release control unit and a prohibition unit. The control unit is configured to control an engagement state of a lock-up clutch, and to perform a slip lock-up control by performing a feedback control of an engagement hydraulic pressure to be a first slip amount during coasting. The abnormality determination unit is configured to determine an abnormality when a state continues with a slip amount being equal to or greater than a second slip amount. The release control unit is configured to release the lock-up clutch when the abnormality is determined. The prohibition unit is configured to allow the control unit to raise the engagement hydraulic pressure by a prescribed pressure, and to prohibit determination by the abnormality determination unit, when the transmission ratio is downshifted during coasting while the slip lock-up control is performed.

A shift control device for a vehicle includes: an engine; a shift mechanism disposed between the engine and driving wheels; a shift control section configured to control a transmission gear ratio of the shift mechanism; and a fuel cut control section configured to stop a fuel supply to the engine, at least when an accelerator pedal is in a release state, and when an engine speed is equal to or greater than a predetermined rotation speed, the shift control section being configured to perform a minimum rotation speed restriction control to control the transmission gear ratio of the shift mechanism so that the minimum rotation speed of the engine is equal to or greater than the predetermined rotation speed regardless of a vehicle front condition and an accelerator operation condition.

A work vehicle includes an engine, a drive wheel, a power transmission mechanism configured to transmit a driving power of the engine to the drive wheel, and a control unit configured to control the power transmission mechanism. The power transmission mechanism has a torque converter including a first clutch, and a second clutch coupled to the torque converter. The control unit controls an oil pressure supplied to the first clutch to a predetermined oil pressure when the second clutch is partially engaged.

A work vehicle includes an engine, a drive wheel, a power transmission mechanism configured to transmit a driving power of the engine to the drive wheel, and a control unit configured to control the power transmission mechanism. The power transmission mechanism has a torque converter including a first clutch, and a second clutch coupled to the torque converter. The control unit controls an oil pressure supplied to the first clutch to a predetermined oil pressure when the second clutch is partially engaged.

An automatic transmission assembly for mounting to a power-source includes a torque converter operatively connected to the power-source. The transmission assembly also includes a turbine shaft for receiving power-source torque from the torque converter. The transmission assembly additionally includes a torque transfer system, having a gear-train and a hydraulic pressure operated torque-transmitting device, for receiving the torque from the turbine shaft and selecting an input-to-output speed-ratio of the transmission. The transmission assembly also includes an output member for receiving torque from torque transfer system and outputting the torque to drive a load. The turbine shaft defines a first passage configured to supply hydraulic pressure to the torque-transmitting device and a second passage configured to vent to atmosphere. The turbine shaft additionally defines a third passage fluidly connecting the first passage to the second passage and thereby configured to bleed air from the torque-transmitting device.

An automatic transmission assembly for mounting to a power-source includes a torque converter operatively connected to the power-source. The transmission assembly also includes a turbine shaft for receiving power-source torque from the torque converter. The transmission assembly additionally includes a torque transfer system, having a gear-train and a hydraulic pressure operated torque-transmitting device, for receiving the torque from the turbine shaft and selecting an input-to-output speed-ratio of the transmission. The transmission assembly also includes an output member for receiving torque from torque transfer system and outputting the torque to drive a load. The turbine shaft defines a first passage configured to supply hydraulic pressure to the torque-transmitting device and a second passage configured to vent to atmosphere. The turbine shaft additionally defines a third passage fluidly connecting the first passage to the second passage and thereby configured to bleed air from the torque-transmitting device.

A torque converter includes a case and a bypass clutch having a plate rotationally fixed to the case and a friction disk having a friction material configured to engage with the plate to rotationally couple the friction disk to the plate when the bypass clutch is engaged. The friction disk includes a first circumferential connection surface having a plurality of alternating convex and concave arcuate segments. A drive plate includes a second circumferential connection surface having a plurality of alternating convex and concave arcuate segments. The first and second connection surfaces are in meshing engagement with the convex segments of the friction disk meshing with the concave segments of the drive plate and with the concave segments of the friction disk meshing with the convex segments of the drive plate.

A torque converter includes a case and a bypass clutch having a plate rotationally fixed to the case and a friction disk having a friction material configured to engage with the plate to rotationally couple the friction disk to the plate when the bypass clutch is engaged. The friction disk includes a first circumferential connection surface having a plurality of alternating convex and concave arcuate segments. A drive plate includes a second circumferential connection surface having a plurality of alternating convex and concave arcuate segments. The first and second connection surfaces are in meshing engagement with the convex segments of the friction disk meshing with the concave segments of the drive plate and with the concave segments of the friction disk meshing with the convex segments of the drive plate.