A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.

A powertrain for a vehicle is disclosed that includes an electromagnetic driving unit (10) and a transmission module (20) comprising a controllable clutch (21) the powertrain further includes a control system to control the electromagnetic driving unit and to control the clutch. The controller has a safety operational mode wherein it controls an engagement of the controllable clutch with a feedback loop in which a desired extent of engagement is positively correlated to a difference between an extent of slip as indicated by the slip indicator and a positive reference value for said extent of slip, wherein the slip indicator indicates the extent of slip with a sign that is the product of the sign of the difference between the rotational speed of the input shaft and a rotational speed of the output shaft and a desired driving torque sign.

An automatic transmission device for a vehicle driven by transmitting a torque of an engine to driving wheels includes a clutch provided in a torque transmission system extending from the engine to the driving wheels, a transmission located between the clutch and the driving wheels in the torque transmission system, and a transmission controller. The transmission controller is configured or programmed to perform a torque feedback-control to bring the clutch into a sliding state in response to issue of a shift command and feedback-control a transmission torque to a target torque, disengage the clutch after the torque feedback-control, change a shift stage of the transmission according to the shift command after disengaging the clutch, and engage the clutch after changing the shift stage.

A clutch torque estimating method for a transmission of a vehicle may include inputting model engine torque to a powertrain model by a controller; inputting target clutch torque of a first clutch and target clutch torque of a second clutch to the powertrain model by the controller; inputting shifting information related to the vehicle to the powertrain model by the controller; correcting the powertrain model in real time by feeding back an engine angular velocity error, a clutch angular velocity error of the first clutch, a clutch angular velocity error of the second clutch, a wheel angular velocity error to the powertrain model by the controller; and estimating clutch torque of the first clutch and clutch torque of the second clutch by determining the powertrain model by the controller.

A clutch torque estimating method for a transmission of a vehicle may include inputting model engine torque to a powertrain model by a controller; inputting target clutch torque of a first clutch and target clutch torque of a second clutch to the powertrain model by the controller; inputting shifting information related to the vehicle to the powertrain model by the controller; correcting the powertrain model in real time by feeding back an engine angular velocity error, a clutch angular velocity error of the first clutch, a clutch angular velocity error of the second clutch, a wheel angular velocity error to the powertrain model by the controller; and estimating clutch torque of the first clutch and clutch torque of the second clutch by determining the powertrain model by the controller.

A driving force transmission control apparatus includes: a driving force transmission device that includes an electromagnetic clutch mechanism configured to generate a frictional force between clutch plates by energization of an electromagnetic coil and transmits a driving force by actuating the electromagnetic clutch mechanism; and a control device that controls the driving force transmission device. The control device includes a storage unit storing a hysteresis value representing the difference between a current value required to transmit a predetermined torque when an energization current to the electromagnetic coil is gradually increased and a current value required to transmit the predetermined torque when the energization current is gradually reduced, a torque command value calculator that calculates a torque command value, and a current command value calculator that calculates a current command value representing a target value of a current to be supplied to the electromagnetic coil based on the torque command value and the hysteresis value.

A control device controls a driving force transmission device that presses a main clutch using an actuator that generates a pressing force according to a supply current. The control device includes a current command value setting unit that sets a current command value based on I-T characteristic information indicating the relationship between a current supplied to the actuator and a driving force transmitted, a correction duration setting unit that sets a correction duration based on a responsiveness related value related to the responsiveness of the main clutch when an increase in the driving force to be transmitted by the main clutch becomes greater than or equal to a threshold, a correction unit that increases and corrects the current command value for the set correction duration, and the current control unit that performs current feedback control such that a current corresponding to the current command value is supplied to the actuator.

A clutch apparatus includes a clutch hub, a clutch drum, a multi-plate clutch having inner clutch plates and outer clutch plates, a piston for pressing the multi-plate clutch, an electric motor, a moving mechanism for moving the piston in an axial direction in accordance with the amount of rotation of the electric motor, and a control unit for controlling the electric motor. When increasing a rotational force that is transmitted between the clutch hub and the clutch drum by increasing electric current that is supplied to the electric motor, the control unit moves the piston in the axial direction by temporarily supplying the electric motor with the electric current having a first current value that is greater than a second current value corresponding to a target rotational force that needs to be transmitted between the clutch hub and the clutch drum.

A method for controlling engagement of a power take-off (PTO) clutch of a work vehicle may generally include transmitting, by a computing device, a control signal associated with initiating engagement of the PTO clutch, determining a clutch slippage energy generated during engagement of the PTO clutch due to clutch slippage and, while the PTO clutch is getting engaged, calculating a clutch engagement time remaining until engagement of the PTO clutch is completed based on the clutch slippage energy and a maximum clutch engagement energy associated with the PTO clutch. In addition, the method may include determining a torque command for controlling engagement of the PTO clutch as a function of the remaining clutch engagement time and controlling the engagement of the PTO clutch based on the torque command.

A vehicle includes a transmission that performs a method of operating a clutch of a vehicle. The vehicle includes the clutch, an actuator device and a processor. The actuator device includes a piston movable to operate the clutch. The processor is configured to receive a pressure signal indicative of a selected fluid pressure for operating the clutch, determine a position for the piston in the actuator device from the pressure signal, and move the piston to the position to operate the clutch at the selected fluid pressure.