| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a four-wheel drive paving machine which exerts a pressure that can obtain a maximum driving force insofar as front wheels do not cause a skid, as a normal pressure of front-wheel driving hydraulic motors, and can augment the driving force of the front wheels only at a specific moment by setting an operating pressure of the front-wheel hydraulic motors to a pressure value higher than the normal pressure only for a very short time, depending on the situation. <P>SOLUTION: The wheel-type self-propelled paving machine is formed of a hydraulic pump 10 driven by an engine, and the hydraulic motors 16 capable of driving the front wheels and rear wheels by pressure oil discharged from the hydraulic pump 10, independently from each other. The paving machine is provided with: a changeover valve 33 which selects either one of relief valves, i.e., a first relief valve 31 for controlling the pressure oil to be supplied from the hydraulic pump 10 to the front-wheel driving hydraulic motors 16, to the preset normal pressure, and a second relief valve 32 for controlling the pressure oil to the pressure value higher than that of the first relief valve 31; and a pressure changeover switch 34. The changeover valve 33 is formed so as to select the second relief valve 32 only at a specific instance, and to set the pressure oil to be supplied to the front-wheel driving hydraulic motors 16 to the higher pressure value. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
