Help with removing jerks in hydraulic cylinder

[navz]

HI

I need help in removing jerks in operation of a double acting hydraulic cylinder. The cylinder has an ID of 80mm, stroke length of 620mm, and shaft diameter of 50mm. I am operating it using a 12 liter pump. I am operating the cylinder using a 4/3 solenoid operated direction valve with tandem neutral. I am able to operate the cylinder, however the cylinder jerks in the initial stages because of sudden acceleration or deacceleration when I move the direction control valve in either direction. What can I do to avoid these jerks, i.e., pressure should build up slowly.

Thanks for your help

 

[hydtools]

Cylinders start better with pressure changing from a high level to a lower level than with pressure starting at a low level. One way is to use a closed-center valve transition from your open-center neutral to cylinder operating position.

Ted

 

[navz]

Thanks for the quick reply. Are you suggesting I change the direction valve from tandem to all ports blocked neutral position? I am stuck with a fixed displacement pump as the motor I use to operate the pump is common with another function so I can’t use a variable displacement pump

 

[hydtools]

If you do that, add an accumulator and an unloader valve. The accumulator to maintain pressure between the unloader valve and closed-center directional valve. The onloader valve to unload, divert to tank, the pump output when the directional valve is centered.

Ted