WORK VEHICLE AND CONTROL METHOD FOR SAME

摘要

The target input shaft torque determination unit determines a target input shaft torque. The target output shaft torque determination unit determines a target output shaft torque so that a deceleration force for decelerating the vehicle is generated on the output shaft of the power transmission device in a state in which connection and disconnection states of the forward travel clutch and the reverse travel clutch are maintained at the state before the start of the shuttle action when the shuttle action is started. The torque-balance information is stored in a storage unit and defines a relationship between the target input shaft torque and the target output shaft torque to achieve a balance of the torques of a power transmission device. The command torque determination unit uses the torque-balance information to determine torque commands for the motor from the target input shaft torque and the target output shaft torque.

主权项

1. A work vehicle, comprising:
an engine; a hydraulic pump driven by the engine; a work implement driven by hydraulic fluid discharged from the hydraulic pump; a travel device driven by the engine; a power transmission device that transmits driving power from the engine to the travel device; a control unit for controlling the power transmission device; a travel direction detecting unit for detecting a travel direction of a vehicle; a forward/reverse travel operating member for selectively switching between a forward travel position and a reverse travel position, and switching between forward travel and reverse travel of the vehicle; and a forward/reverse travel position detecting unit for detecting a position of a forward/reverse travel operating member; the power transmission device including
an input shaft;an output shaft;a gear mechanism including a planetary gear mechanism to transmit rotation of the input shaft to the output shaft;a motor connected to a rotating element of the planetary gear mechanism; anda forward/reverse travel switch mechanism including a forward travel clutch and a reverse travel clutch, the forward travel clutch being connected and the reverse travel clutch being disconnected when the vehicle is traveling forward and the forward travel clutch being disconnected and the reverse travel clutch being connected when the vehicle is traveling in reverse;the power transmission device configured so that a rotation speed ratio of the output shaft with respect to the input shaft is changed by changing the rotation speed of the motor; the control unit including
a shuttle action evaluating unit for determining that the vehicle is in a shuttle action when a direction corresponding to a position of the forward/reverse travel operating member and a traveling direction of the vehicle differ;a target input shaft torque determination unit for determining a target input shaft torque which is a target value of a torque on the input shaft of the power transmission device;a target output shaft torque determination unit for determining a target output shaft torque which is a target value of a torque on the output shaft of the power transmission device, so that a deceleration force for decelerating the vehicle is generated on the output shaft of the power transmission device in a state in which the connection and disconnection states of the forward travel clutch and the reverse travel clutch are maintained at a state before the start of the shuttle action when the shuttle action is started;a storage unit for storing torque-balance information for defining a relationship between the target input shaft torque and the target output shaft torque so that a balance of the torques in the power transmission device is achieved; anda command torque determination unit using the torque-balance information to determine a command torque for the motor from the target input shaft torque and the target output shaft torque.