Working vehicle

Abstract

A working vehicle includes a control valve unit with a service actuator control valve, a first drive unit, a travel unit, a lower body, an upper body, a cab, a plurality of work units and a plurality of hydraulic traveling motors, an operation unit, a quick hitch, an attachment, a trigger-switch, a plurality of solenoid valves and a plurality of pipelines, and a controller. The controller performs control that, in a case where the controller receives the trigger signal from the trigger-switch to release the lock of the quick hitch, the pressure oil in the plurality of pipelines is returned to the hydraulic oil tank by energizing the plurality of solenoid valves with the first drive unit stopped.

What is claimed is: 
     
         1 . A working vehicle comprising:
 a control valve unit with a service actuator control valve;   a first drive unit supplying hydraulic oil to a primary side of the control valve unit;   a travel unit;   a lower body provided with the travel unit;   an upper body slewably disposed on the lower body;   a second drive unit causing the upper body to slew;   a cab disposed in the upper body;   a plurality of work units and a plurality of hydraulic traveling motors driven by pressure oil from secondary side of the control valve unit;   an operation unit operated by an operator;   a quick hitch that is driven by the pressure oil to lock in a state of being attached to an arm of the working unit;   an attachment that comes to connect to the arm in response to the locking;   a trigger-switch for sending a trigger signal according to operation by the operator;   a plurality of solenoid valves of the service actuator control valve;   a plurality of pipelines connected to the service actuator control valve;   a hydraulic oil tank; and   a controller,   wherein the controller performs control that, in a case where the controller receives the trigger signal from the trigger-switch to release the lock of the quick hitch, the pressure oil in the plurality of pipelines is returned to the hydraulic oil tank by energizing the plurality of solenoid valves with the first drive unit stopped.   
     
     
         2 . The working vehicle according to  claim 1 ,
 wherein the controller performs control that the pressure oil is returned by alternately energizing the plurality of solenoid valves provided on both sides of a spool of the service actuator control valve.   
     
     
         3 . The working vehicle according to  claim 2 ,
 wherein the controller performs control that the first drive unit is operated and the lock of the quick hitch is released after a first term required for returning the pressure oil has elapsed.   
     
     
         4 . The working vehicle according to  claim 3 ,
 wherein the controller performs control that operation of a service actuator connected to the service actuator control valve is not received in a second term in which the trigger-switch is operated.   
     
     
         5 . The working vehicle according to  claim 1 ,
 wherein the trigger-switch includes a first button and a second button that are provided in the cab, and the trigger-switch sends the trigger signal in response to both the first button and the second button pressed.   
     
     
         6 . The working vehicle according to  claim 2 ,
 wherein the trigger-switch includes a first button and a second button that are provided in the cab, and the trigger-switch sends the trigger signal in response to both the first button and the second button pressed.   
     
     
         7 . The working vehicle according to  claim 3 ,
 wherein the trigger-switch includes a first button and a second button that are provided in the cab, and the trigger-switch sends the trigger signal in response to both the first button and the second button pressed.   
     
     
         8 . The working vehicle according to  claim 4 ,
 wherein the trigger-switch includes a first button and a second button that are provided in the cab, and the trigger-switch sends the trigger signal in response to both the first button and the second button pressed.