A milling machine includes a rotor drive transmission having a plurality of gears disposed between a prime mover and a cutting rotor. The rotor drive transmission is associated with a rotor transmission hydraulic circuit including a hydraulic gearshift actuator to engage the plurality of gears in one or more gear ratios and a gearshift directional control valve to direct hydraulic fluid to and from the hydraulic gearshift actuator. In occurrence of a fault condition, the rotor transmission hydraulic circuit includes a gearshift trapping valve to maintain hydraulic pressure in the hydraulic gear actuator and the engaged gear ratio of the rotor drive transmission.

The present invention addresses the problem of obtaining an electronic control device for a vehicular automatic transmission that suppresses sudden acceleration, sudden deceleration, and gear shift shock that occur when the transmission moves into a fail-safe mode due to the electronic control device stopping during a main CPU abnormality. An electronic control device 100 for a vehicular automatic transmission has: a main CPU 3 that performs gear shift control for the vehicular automatic transmission; and a sub-CPU 4 that detects abnormalities in the main CPU 3. When the sub-CPU 4 detects an abnormality in the main CPU 3 while the vehicle is traveling, the sub-CPU 4 stops the gear shift control executed by the main CPU 3. Next, when the control status of the vehicular automatic transmission is in a state of maintaining the gear position, the sub-PCU 4 continues the maintaining of the gear position; when the control status is in a state of changing the gear position, the sub-PCU 4 continues a gear shift operation for the gear position, and, instead of the main CPU 3, performs alternative control for maintaining the gear position after the gear position is changed. Subsequently, as a result of a stop in the traveling of the vehicle, the sub-PCU 4 finishes the alternative control and abnormally stops the electronic control of the automatic transmission.

A shift range control device includes: multiple controllers that communicate with each other and control driving of a motor. The multiple controllers share control information, and include a first controller and a second controller. When the control information of the first controller is different from the control information of the second controller, one of the first controller and the second controller is set as a continuation controller, and a different one of the first controller and the second controller is set as a stop controller. The stop controller stops the drive control. The continuation controller performs the drive control of the motor.

A power supply controller includes a driver having a circuit board and controlling an operation of an electric oil pump, a control unit controlling power supply to the driver, a board temperature sensor detecting a temperature of the circuit board; and an oil temperature sensor detecting a temperature of a working oil of a transmission as an oil temperature. The control unit executes energization prohibition control for prohibiting power supply to the driver when the temperature of the circuit board detected by the board temperature sensor exceeds a predetermined first threshold temperature, and executes cancellation determination for determining whether to cancel the energization prohibition control based on the oil temperature detected by the oil temperature sensor during execution of the energization prohibition control.

A hydraulic control apparatus including a first and second control valves switched to exert hydraulic pressure on a piston to press toward first position, a third and fourth control valves switched to exert hydraulic pressure on the piston to press toward second position and, a CPU. The CPU performs executing a first process controlling the control valves so that hydraulic pressure is exerted by switching of the first, second and third control valves or a second process controlling the control valves so that hydraulic pressure is exerted by switching of the second control valve and determining that the first control valve is failed when movement of the piston to the first position is not detected through the first process and determining that the third control valve is failed when movement of the piston to the first position is not detected through the second process.

In an apparatus for controlling an automatic transmission having gear engaging mechanisms installed to engage one of gears to establish n-th speed when supplied with hydraulic pressure discharged from an oil pump driven by a prime mover, an electromagnetic pressure-regulating valve installed to pressure-regulate the hydraulic pressure, an electromagnetic shift valve installed at a hydraulic passage to supply the hydraulic pressure to the gear engaging mechanisms, and a current supply circuit to supply current to the solenoid valve, cut-off of current supply to the solenoid valve from the current supply circuit is delayed by a predetermined time period, when the ignition switch is turned off.

Ground wires are shared between a drive-side pulley solenoid valve and a driven-side pulley solenoid valve. Therefore, when a disconnection or short circuit occurs in the shared portion, a drive-side pulley and a driven-side pulley show substantially the same behavior. As a result, changes in the speed ratio γcvt of a continuously variable transmission are suppressed and changes in vehicle behavior are also suppressed. Therefore, it is possible to suppress the degradation of drivability during the failure of the solenoid valves involved in power transmission.

A PWM control part rotationally drives a motor based on a PWM control value. A rotation speed control part controls a rotation speed of the motor. A rotation angle detection part detects a rotation angle of the motor. A reference position learning part controls the motor to rotate at a constant rotation speed until a detent plate stops at a limit position of a movable range and learns a reference position of the motor. A current detection circuit detects a current value corresponding to a driving current. A current limitation part limits a current supplied to the motor. A PWM control value limitation part controls the PMW control value to be equal to or smaller than a PWM limitation value, which is a predetermined value. A relation check part checks whether a relation between a current value detected by the current detection circuit and the PWM control value is inappropriate.

A control apparatus for a vehicular continuously variable transmission is provided. The control apparatus includes a pair of pulley pressure adjusting valves, a pair of electromagnetic valves, a source pressure adjusting valve and an electronic control unit. The electronic control unit is configured to control the source pressure adjusting valve in such a manner as to lower the source pressure at a time of a fail mode below the source pressure at a time of a non-fail mode, at the time of the fail mode, and control command signals to the pair of the electromagnetic valves such that the command signals temporarily decrease below command signals at the time of the non-fail mode, before cancelling the lowering of the source pressure in making a changeover from the fail mode to the non-fail mode.

A control device provided in a gear shifting device includes an electronic control unit. The electronic control unit determines whether an abnormality of the gear shifting device has occurred, performs a fail-safe process of switching the frictional engagement element corresponding to an abnormality to a disengaged state and fixing the gear shift ratio of the gear shifting device when it is determined that an abnormality has occurred, determines whether the abnormality has been relieved based on a behavior of an input signal at the time of operating a drive device of the frictional engagement element corresponding to an abnormality on condition that the frictional engagement element is maintained in the disengaged state after it is determined that the abnormality has occurred, and releases the fail-safe process when it is determined that the abnormality has been relieved.