| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydraulic control structure of a farming tractor capable of securing oil amount required for an elevating control circuit of a rotary tilling device by effectively making the most of a flow dividing valve. <P>SOLUTION: In this structure, the elevating control circuit for elevating and controlling the rotary tilling device A and a control circuit for a power steering device are provided, the main flow dividing valve 34B is provided to preferentially control pressure oil, feed the pressure oil to the control circuit for the power steering device and feed excess flow to the elevating control circuit, and a bypass passage f is formed to connect an oil feeding passage a from a hydraulic pump P to the main flow dividing valve 34B to the elevating control circuit and detour the main flow dividing valve 34B. An auxiliary flow dividing valve 34A is provided in the bypass passage f. A control flow that the pressure oil from the hydraulic pump P is controlled by the auxiliary flow dividing valve 34A is preferentially supplied to the elevating control circuit. The excess flow is fed to the main flow dividing valve 34B side from a connecting portion with the bypass passage f in the oil feeding passage a. <P>COPYRIGHT: (C)2009,JPO&INPIT |
