Wheel Loader

Abstract

A wheel loader includes: an operating state detecting unit detecting an operating state; a target setting unit setting a relationship between a target position of a working equipment and a travel distance of the wheel loader for the operating state detected by the operating state detecting unit; a travel distance detecting unit detecting the travel distance of the wheel loader; and a working equipment controlling unit moving a boom and a bucket to the target position of the working equipment determined depending on the travel distance detected by the travel distance detecting unit.

1 . A wheel loader comprising:
 working equipment comprising a boom and a bucket attached to the boom;   an operating state detecting unit configured to detect an operating state of the wheel loader;   a target setting unit configured to set a relationship between a target position of the working equipment and a travel distance of the wheel loader for the operating state detected by the operating state detecting unit;   a travel distance detecting unit configured to detect the travel distance of the wheel loader; and   a working equipment controlling unit configured to move the boom and the bucket to the target position of the working equipment determined depending on the travel distance detected by the travel distance detecting unit.   
     
     
         2 . The wheel loader according to  claim 1 , wherein
 the operating state detecting unit comprises:
 a load determining unit configured to determine whether or not the bucket is loaded; and 
 a forward/reverse travel determining unit configured to determine whether the wheel loader travels forward or reverses, 
   when the load determining unit determines that the bucket is loaded and the forward/reverse travel determining unit determines that the wheel loader reverses, the operating state is detected to be a loaded reverse traveling state,   the target setting unit sets the relationship between the target position of the working equipment and the travel distance of the wheel loader for the loaded reverse traveling state, and   the working equipment controlling unit moves the boom and the bucket to the target position of the working equipment determined depending on the travel distance detected by the travel distance detecting unit when the operating state is the loaded reverse traveling state.   
     
     
         3 . The wheel loader according to  claim 1 , wherein
 the operating state detecting unit comprises:
 a load determining unit configured to determine whether or not the bucket is loaded; and 
 a forward/reverse travel determining unit configured to determine whether the wheel loader travels forward or reverses, 
   when the load determining unit determines that the bucket is loaded and the forward/reverse travel determining unit determines that the wheel loader travels forward, the operating state is detected to be a loaded forward traveling state,   the target setting unit sets the relationship between the target position of the working equipment and the travel distance of the wheel loader for the loaded forward traveling state, and   the working equipment controlling unit moves the boom and the bucket to the target position of the working equipment determined depending on the travel distance detected by the travel distance detecting unit when the operating state is the loaded forward traveling state.   
     
     
         4 . The wheel loader according to  claim 1 , wherein
 the operating state detecting unit comprises:
 a load determining unit configured to determine whether or not the bucket is loaded; and 
 a forward/reverse travel determining unit configured to determine whether the wheel loader travels forward or reverses, 
   when the load determining unit determines that the bucket is unloaded and the forward/reverse travel determining unit determines that the wheel loader reverses, the operating state is detected to be an unloaded reverse traveling state,   the target setting unit sets the relationship between the target position of the working equipment and the travel distance of the wheel loader for the unloaded reverse traveling state, and   the working equipment controlling unit moves the boom and the bucket to the target position of the working equipment determined depending on the travel distance detected by the travel distance detecting unit when the operating state is the unloaded reverse traveling state.   
     
     
         5 . The wheel loader according to  claim 2 , wherein the target setting unit: sets a boom angle in proportion to the travel distance to define a target position of the boom for the loaded reverse traveling state, the boom angle varying from a value at a start of a movement of the boom in the loaded reverse traveling state to a value at which the boom is to get horizontal when the travel distance of the wheel loader reaches a distance L1; and sets a bucket cylinder length where the bucket is maintained at a tilting position in accordance with the boom angle to define a target portion of the bucket for the loaded reverse traveling state. 
     
     
         6 . The wheel loader according to  claim 3 , wherein
 the target setting unit sets a distance L2 as a target travel distance for the loaded forward traveling state, a first interim distance less than the distance L2, and a second interim distance equal to or more than the first interim distance but less than the distance L2,   when the travel distance is less than the first interim distance, the target setting unit: sets a first boom angle at which the boom is to get horizontal to define a target position of the boom for the loaded forward traveling state; and sets a first bucket cylinder length where the bucket is maintained at a tilting position to define a target position of the bucket for the loaded forward traveling state,   when the travel distance is equal to or more than the first interim distance but less than the second interim distance, the target setting unit: sets a second boom angle in proportion to the travel distance to define the target position of the boom for the loaded forward traveling state, the second boom angle varying from a value at a time when the travel distance reaches the first interim distance to a value at which the boom is to reach a preset lifted positioner position when the travel distance reaches the second interim distance; and sets a second bucket cylinder length where the bucket is maintained at the tilting position in accordance with the second boom angle to define a target portion of the bucket for the loaded forward traveling state, and   when the travel distance is in a range from the second interim distance to the distance L2, the target setting unit: sets a third boom angle at which the boom is to reach the lifted positioner position to define the target position of the boom for the loaded forward traveling state; and sets a third bucket cylinder length where the bucket is maintained at the tilting position to define the target position of the bucket for the loaded forward traveling state.   
     
     
         7 . The wheel loader according to  claim 4 , wherein
 the target setting unit sets a distance L2 as a target travel distance for the unloaded reverse traveling state, a third interim distance less than the distance L2, and a fourth interim distance equal to or more than the third interim distance but less than the distance L2,   when the travel distance is less than the third interim distance, the target setting unit: sets a first boom angle at which the boom is to reach a preset lifted positioner position to define a target position of the boom for the unloaded reverse traveling state; and sets a first bucket cylinder length in proportion to the travel distance to define a target position of the bucket for the unloaded reverse traveling state, the first bucket cylinder length varying from a value at a start of a movement of the bucket in the unloaded reverse traveling state to a value where the bucket is to reach a preset initial position when the travel distance of the wheel loader reaches the third interim distance,   when the travel distance is equal to or more than the third interim distance but less than the fourth interim distance, the target setting unit: sets a second boom angel in proportion to the travel distance to define the target position of the boom for the unloaded reverse traveling state, the second boom angle varying from a value at a time when the travel distance reaches the third interim distance to a value at which the boom is to get horizontal when the travel distance reaches the fourth interim distance; and sets a second bucket cylinder length where the bucket is maintained at the preset initial position to define the target position of the bucket for the unloaded reverse traveling state, and   when the travel distance is in a range from the fourth interim distance to the distance L2, the target setting unit: sets a third boom angle in proportion to the travel distance to define the target position of the boom for the unloaded reverse traveling state, the third boom angle varying from a value at a time when the travel distance reaches the fourth interim distance to a value at which the boom is to reach a preset lowered positioner position when the travel distance reaches the distance L2; and sets a third bucket cylinder length where the bucket is maintained at the preset initial position to define the target position of the bucket for the unloaded reverse traveling state.   
     
     
         8 . The wheel loader according to  claim 1 , further comprising:
 a boom position detecting unit configured to detect a current position of the boom; and   a bucket position detecting unit configured to detect a current position of the bucket, wherein   the target setting unit calculates a current target position of each of the boom and the bucket from the current travel distance detected by the travel distance detecting unit,   the working equipment controlling unit calculates a deviation between the current target position of the boom and the current position of the boom detected by the boom position detecting unit and a deviation between the current target position of the bucket and the current position of the bucket detected by the bucket position detecting unit, and   each of the boom and the bucket is moved based on the deviations.   
     
     
         9 . The wheel loader according to  claim 1 , further comprising:
 a boom lever for operating the boom; and   a bucket lever for operating the bucket, wherein   the working equipment controlling unit adds displacement of the boom lever and the bucket lever by a manual operation to move the working equipment.   
     
     
         10 . The wheel loader according to  claim 1 , further comprising:
 a boom lever for operating the boom; and   a bucket lever for operating the bucket, wherein   the working equipment controlling unit stores a travel distance at a time when the working equipment reaches the target position when displacement of the boom lever and the bucket lever by a manual operation is added, and   the target setting unit corrects the travel distance of the wheel loader defined by the relationship between the position of the working equipment and the travel distance of the wheel loader with the travel distance stored when the working equipment reaches the target position.