Work vehicle and method for controlling work vehicle

Abstract

A work vehicle includes a vehicular body, a work implement, a manipulation unit and a controller. The work implement has a boom pivotable with respect to the vehicular body, a dipper stick pivotable with respect to the boom, and a bucket pivotable with respect to the dipper stick. The manipulation unit is operated to output a manipulation command for the work implement. The controller controls the work implement in accordance with the manipulation command received from the manipulation unit. When in accordance with the manipulation command via the manipulation unit the bucket travels in a direction on the side of the back surface of the bucket with respect to the direction of the cutting edge of the bucket, the controller limits movement of the bucket in the direction in accordance with the manipulation command.

1 . A work vehicle comprising:
 a vehicular body;   a work implement having a boom pivotable with respect to the vehicular body, a dipper stick pivotable with respect to the boom, and a bucket pivotable with respect to the dipper stick;   a manipulation unit operated to output a manipulation command for the work implement; and   a controller that controls the work implement in response to the manipulation command received from the manipulation unit,   when in accordance with the manipulation command via the manipulation unit the bucket travels in a direction on a side of a back surface of the bucket with respect to a direction of a cutting edge of the bucket, the controller limiting movement of the bucket in the direction in accordance with the manipulation command.   
     
     
         2 . The work vehicle according to  claim 1 , wherein when in accordance with the manipulation command via the manipulation unit the bucket travels in the direction of the cutting edge of the bucket or a direction on a side of an open side of the bucket with respect to the direction of the cutting edge of the bucket, the controller moves the bucket in the direction in accordance with the manipulation command. 
     
     
         3 . The work vehicle according to  claim 1 , wherein when in accordance with the manipulation command via the manipulation unit the bucket travels in a direction within a range of a predetermined angle on a side of an open side of the bucket with respect to the direction of the cutting edge of the bucket, the controller limits movement of the bucket in the direction in accordance with the manipulation command. 
     
     
         4 . The work vehicle according to  claim 3 , wherein when in accordance with the manipulation command via the manipulation unit the bucket travels in a direction outside the range of the predetermined angle on the side of the open side of the bucket with respect to the direction of the cutting edge of the bucket, the controller moves the bucket in the direction in accordance with the manipulation command. 
     
     
         5 . The work vehicle according to  claim 1 , wherein limiting movement of the bucket in the direction in accordance with the manipulation command prohibits the bucket from moving in the direction. 
     
     
         6 . The work vehicle according to  claim 1 , wherein when in accordance with the manipulation command via the manipulation unit the bucket travels in the direction on the side of the back surface of the bucket with respect to the direction of the cutting edge of the bucket, the controller changes the direction in which the bucket travels to a predetermined direction on the side of the open side of the bucket, and the controller moves the bucket in the predetermined direction. 
     
     
         7 . The work vehicle according to  claim 1 , wherein
 the manipulation unit outputs at least one of a first manipulation command for the boom, a second manipulation command for the dipper stick, and a third manipulation command for the bucket, and   the controller prohibits movement of the boom when the bucket travels in the direction on the side of the back surface of the bucket with respect to the direction of the cutting edge of the bucket as the boom moves in response to the first manipulation command output from the manipulation unit,   the controller prohibits movement of the dipper stick when the bucket travels in the direction on the side of the back surface of the bucket with respect to the direction of the cutting edge of the bucket as the dipper stick moves in response to the second manipulation command output from the manipulation unit, and   the controller prohibits movement of the bucket when the bucket travels in the direction on the side of the back surface of the bucket with respect to the direction of the cutting edge of the bucket in response to the third manipulation command output from the manipulation unit.   
     
     
         8 . The work vehicle according to  claim 1 , wherein
 the controller determines whether the work implement performs an excavation work, and   when the controller determines that the work implement performs the excavation work, and the bucket travels in the direction on the side of the back surface of the bucket with respect to the direction of the cutting edge of the bucket in accordance with the manipulation command output from the manipulation unit, the controller limits movement of the bucket in the direction in accordance with the manipulation command.   
     
     
         9 . The work vehicle according to  claim 8 , wherein the controller determines whether the work implement performs an excavation work in accordance with a manipulation instruction of an operator. 
     
     
         10 . A method for controlling a work vehicle including a work implement having a boom pivotable with respect to a vehicular body, a dipper stick pivotable with respect to the boom, and a bucket pivotable with respect to the dipper stick, comprising:
 receiving a command for the work implement; and   controlling the work implement in accordance with the command,   the step of controlling the work implement including, when in accordance with the command the bucket travels in a direction on a side of a back surface of the bucket with respect to a direction of a cutting edge of the bucket, limiting movement of the bucket in the direction in accordance with the command.