抄録
Spherical poppet valves are used for pressure, flow and direction control in many oil hydraulic systems as they can be produced with low cost using marketed hard steel balls.
In this paper, a spherical poppet valve is used for pressure or flow control, and basic valve characteristics are experimentally studied under a relatively small valve opening condition. The flow rate characteristics, thrust force characteristics, cavitation condition and the effect of cavitation on valve characteristics are investigated using several kinds of typical formed valves with different shaped seats such as; sharp edged seat, spherical chamfered seat and conical chamfered seat. Observation of cavitation and measurement of pressure distribution in the valve are made with a half-cut model of the test apparatus. As a result, effects of the ratio of the spherical poppet diameter to the valve seat diameter, the length of the spherical chamfer on the seat, the difference of the shape of restriction orifice formed by the spherical poppet surface and the conical chamfered seat, are revealed.
