Yuken Poppet Type Solenoid Controlled Pilot Operated Directional Control Valves
These valves are solenoid controlled pilot operated directional valves, which are made multi-functionable by granting individual poppet functions, such as directional control, flow control, and pressure control. They consist of a main valve with four poppets, a solenoid operated directional valve for the pilot line, and a pilot selector valve. These valves are used in large-scale hydraulic systems including press and compressing machines.
They have mounting faces of the same size as those of the conventional spool valves; however, they provide the following features.
(1) They have three functions in one body: directional control, flow control, and check valve for pilot operation (counterbalance valve). They reduce the number of valves in applications and installation space.
(2) Changeover response time is short as the valves are the poppet type. This characteristic eliminates valve overlap. Neither hydraulic leakage from the seat parts nor hydraulic locking is expected.
(3) By selecting proper orifice diameters for the pilot, open/close timing of the flow passage can be set freely. Therefore, together with the shockless type poppets, a smooth start/stop of the actuators can be achieved. Both the noise of the actuator operation switch and line vibration in hydraulic systems can also be minimized.
(4) Control of the pilot line offers independent open/ close operation of four poppets; the four-position four-way valve type is also available to create a differential circuit. By adopting a differential circuit, gaining high-speed feed by using a smaller volume pump is possible, and the electric power for the systems can be saved.
Figure 4.6 shows the poppet type solenoid controlled pilot operated directional valve (DSLHG-06), and Table 4.8 shows examples of the valve functions.
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