Basic hydraulic piston/rod seal design

[red92s]

Hi All,

While I've got a bit of experience incorporating standard o-rings and grooves into designs for low-pressure plumbing equipment, I've recently been thrust into a bit of fluid power stuff as well.

I'm struggling to find information about best practices for creating a robust and reliable piston-to-rod seal. It's easy to find gobs of information about gland-to-rod seals, and piston-to-cylinder applications, but not for the piston/rod interface. This is for a very basic hydraulic cylinder, with a target operating range of 2500-3000 psi. Historically, we've used a basic radial o-ring (no backups) to create this seal, but I'm not confidant that will work for the intended pressures. A face sealing o-ring on the top or bottom of the piston can get to a higher pressure capability, but I'm not sure how to approach sizing a face seal gland seeing pressure from both sides. Is there common seals made for these applications? Thanks as always.

 

[hydtools]

See the Parker O-ring guide. It is a static seal. Put backup rings on both sides of an o-ring for a rod-to-piston seal. Either the goove in the rod or the grove in the piston like a gland seal.

Ted

 

[red92s]

Thanks. I figured that was a viable/probable solution, I just didn't know if there was anything designed specifically for that type of application. The Parker hydraulic/pneumatic handbook is 400+ pages of seals, and that interface isn't even mentioned.

 

[hydtools]

Well, it is mentioned. It is a static male or female gland. Not specifically a piston-to-rod arrangement as are the dynamic glands for piston-to-cylinder and rod-to-cylinder seal glands. There are so many static gland possibilities that showing a specific case of piston-to-rod is not necessary.

Ted

 

[pob786]

Hi, There is also information on the James Walker "O Ring" site, with dimensions etc.
JP.