Patent ID: 7770597

Claim:
A spool valve system, comprising: a valve main body with, from a first side to a second side, an input port to which an input pressure is supplied, an output port that outputs an output pressure, and a drain port that discharges the input pressure; and a spool that is structured to move freely relative to the valve main body, the spool including, from the first side to the second side, a first land, a groove that is formed adjacent to the first land, and a second land that is formed adjacent to the groove, wherein: the groove includes, from the first side to the second side, a first tapered portion that is formed from the first land to a neck portion, the neck portion, a second tapered portion that is formed from the neck portion to a third tapered portion, and the third tapered portion that is formed between the second tapered portion and the second land; an angle of the third tapered portion in relation to an axial center of the spool is smaller than an angle of the second tapered portion in relation to the axial center of the spool; the second tapered portion is formed such that, when an axial direction edge portion between the first land and the groove is positioned between an axial direction edge portion on a non-driving portion side of the input port and an axial direction edge portion on a driving portion side of the input port, a face of the output port that extends in a radial direction is positioned on a line that is an extension of the second tapered portion, and oil supplied by the input port is discharged from the output port; and the second land is formed such that, when a prescribed amount of the oil passes through a gap between an axial direction edge portion on a non-driving portion side of the drain port and an axial direction edge portion on a non-driving portion side of the second land and is sent to the drain port, the ratio of the flow through the input port and the drain port is controlled, and adjusted hydraulic pressure is output as output pressure from the output port.