Patent ID: 7578313

Claim:
A rotary pilot valve comprising: a pair of notch grooves formed in a peripheral face of a rotary valve; a tank port, a pump port, and an output port formed in an inner peripheral face of a body; a pair of variable throttles respectively formed on a side of the pump port and a side of the tank port of the pair of notch grooves; an operating lever for operating the rotary valve by rotation, wherein throttle open areas of the pair of variable throttles are formed in such shapes that the throttle open area of one of the variable throttles gradually increases while the throttle open area of the other gradually reduces according to a rotation angle of the rotary valve by the operating lever, wherein an intermediate throttle pressure between the pump port and the tank port and substantially proportional to the rotation angle of the rotary valve is output from the notch groove to the output port wherein the pair of notch grooves is formed in pressure balance positions in a diameter direction of the rotary valve, wherein the pair of notch grooves communicate with each other through a balance hole, wherein the variable throttles are formed at the notch groove for communicating between the pump port and the tank port, wherein the intermediate throttle pressure is output from the notch groove to the output port, wherein the two sets each including the tank port, the output port and the pump port respectively disposed in positions along normal and reverse rotating directions of the rotary valve around the tank port are formed, wherein the intermediate throttle pressure between the pump port and the tank port in one of the sets is output to the output port of a same set by normal and reverse rotations of the rotary valve by the operating lever, wherein two pairs of notch grooves are formed in positions separate from each other along a direction of a rotation axis of the rotary valve, and wherein the tank ports, the output ports, and the pump ports of the respective sets are disposed in positions corresponding to the respective pairs of notch grooves separate from each other.