Hi all. Just wondering can anybody explain to me what a shockless valve does and how it works. I see them between the pilot control valves and valve chest on excavators but never understood them.
YouTube ram and how spool and valve works
I know how a ram and spool valve work this is more technical
A shockless valve is installed in the pilot circuit between the pilot valve and control valve essentially to reduce shock if you pull the pilot lever then release it suddenly. It prevents a high shock through the main hydraulic circuit. Basically when you release the pilot lever, instead of just dumping all the pilot pressure immediately and causing the spool in the control valve to close cauasing a shock in that particulate circuit, it basically bleeds off the pilot pressure causing the main spool to fully close more slowly.
Sounds like a plain old flow control valve, a simple restriction, maybe with a check so it only works in one direction. Needle valve would probably accomplish the same thing.
Good day Irish in Oz This may help the explanation comes from the Hitachi manual. Kind regards Uffex SHOCKLESS VALVE Beside the shockless valve, a check valve, pressure sensor (arm roll-in), pressure sensor (boom raise), and pressure sensor (swing) are provided in the shockless valve block. The shockless valve regulates the return oil from the control valve spool to the pilot valve, preventing abrupt and rapid movement of the respective control valve spools. The shockless valve regulates the secondary pilot pressure oil for the arm roll-in operation.