Cylinder and Piston Clearance

We have a cylinder here that broke after a long time but it had .001 inch per side clearance.Now i would think the smaller you can make the clearance the better the cylinder would be as long as manufacturing can make it concentric and/or precise enough

Is this working as a pump or motor?

Tolernace for Hyd. pistons is usually determined by the required pressure and the seals used in the piston. see http://www.simrit.de/web/public/home - they have in their catalog a comprehensive overview of various dynamic sealing methods.

Just note that the barrel (the piston's cylinder) is a standard product that can be bought with predefined tolerance of usually H8 to H6. the rod (moving part) can be bought with tolerances of class f7 or g7.

Hope this helps.

The clearance depends upon the pressure at which the hydraulic cylinder will be subjected to.

If the pressure is very high then the pressure will be acting radially on the area of clearance. if the clearance is more naturally the seals will be subjected to this pressure and resulting force.

For energising seals type the clearance kept is 0.2 mm i.e if the bore of the cylinder is 250 mm then the dia of the piston will be 249.8 mm.

you can go on the site of Bushak and shamban who are the leaders of the seals manufacturers and known to everybody who deals with hydraulic cylinders and seals.

regards

hari

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