Selecting Annular Hydraulic Piston Seal

[gcarmich]

I am looking for the proper type of seal for an annular hydraulic piston that might be used in a bolt tensioner or concentric clutch slave cylinder? I have seen that some bolt tensioners use piston o-ring seals in the inner and outer walls and concentric slave cylinders use a seal underneath -possibly a symmetric double lipped type seal. I am more interested in the underneath type seal as it would be easier to design around and implement. Is there a specific name for this type of seal? Thank you, Gil

 

[TugboatEng]

Are you describing a "hydraulic nut"?

I don't see anything unique about this arrangement. Standard hydraulic piston seals or o-rings should apply up to 10k psi. I don't know much about seals for the 40k psi type.

 

[hydtools]

Do you have a sketch or picture of your word description?

Ted

 

[gcarmich]

I took a concentric slave cylinder apart and measured the seal. I recreated a CAD drawing of it (see image). It is a symmetrical seal with a grove on the bottom and flat on the top.

The seal flares out on the sides

I also found a cutaway view of a concentric slave cylinder and circled the piston seal location in red (see other image).

 

[hydtools]

That would be a symmetrical rod or piston seal. Sometimes called a u-cup seal. The attachment to the end of the concentric piston is probably a special feature.

Ted

 

[gcarmich]

Do the walls of the cylinder need to be honed or prepped in a certain way to ensure a good seal as the piston and seal move up and down in the cylinder?

 

[TugboatEng]

Yes, hydraulic cylinders are typically finished with a hone.

 

[gcarmich]

Is there an established method for honing the inner and out walls of a small ring cylinder? Getting a traditional honing tool into the narrow space between the walls would be difficult.