抄録
A logic valve is a controllable check valve consisting of a poppet, a sleeve and a return spring. This type of valve is mostly used as an on/off valve. Since the demands for proportional control of flow rate have been increased, these valves have been used for the proportional control. However, a seat valve is not suitable for flow control.In this paper, to make the logic valve controllable for flow, a new poppet structure is proposed.
The new poppet has been designed based on balance of forces by rearranging area ratio of the poppet. Determining areas so that unbalance force caused by supply pressure and pilot pressure is canceled by spring force, the valve lift can be proportionally controlled by the pilot pressure.
PWM control of the pilot pressure is also investigated. An attenuator is used to reduce pressure fluctuation caused by PWM drive of a pilot valve. Combination of the new type poppet and the attenuator is the PWM-controlled logic valve. Using the simulation model of the attenuator circuit, flow characteristics of the PWM-controlled logic valve can be calculated.
