Hydraulic Cylinder Design 1

[kander]

All,

We are currently looking at designing a cylinder without the help from a cylinder manufacturer. The cylinder will be 3.3m long and have a capacity of around 10Te at about 200Bar. The cylinder will be trunnion mounted behind the end cap and clevis mounted at the rod end.

As you will imagine the design of the cylinder will driven more by buckling that rod / bore diameters.

Does anyone have an idea where I can get a spreadsheet, data sheet, or similar that I can design the cylinder myself taking into account all the parameters that a cylinder manufacturer would cater for?

 

[MikeHalloran]

Your cylinder may be quite a bit longer than its usable stroke. Consult your favorite cylinder mfgr's engineering data, specifically the section about selecting a 'stop tube'.



Mike Halloran
Pembroke Pines, FL, USA

 

[scastillo]

Just curious, why the decision to do it yourself rather than a dedicated cylinder manufacturer? They have all the engineering already worked out and components readily available.

 

[automatic2]

and the price is likely less than if you fab yourself. Only time it makes sense is when you have a custom requirement beyond thier shelve inventory.

As previously indicated, leaving some rod in the cylinder distributes the load, however you need to remember that cylinders as such are designed for linear loads and will not accept a great deal of sideloading, either on the rod or the mount configuration.

 

[CanuckMiner]

Check

http://www.nfpa.com

(National Fluid Power Association) and search for cylinder standards...

http://www.nfpa.com/Standards/Standards_StandardsLocator.asp?pid=355

Cheers,
CanuckMiner

 

[kander]

We don't intend to carry out the build of the cylinder ourselves, only the design. We are looking at getting it built in a middle east country and due to the communication barriers involved we can have a much better handle on the manufacture if we only supply drawings of what we want.

I am reluctant to lead cylinder manufacturers 'up the garden path' to supply a cylinder design that we no intentions of issuing a PO for.

 

[EdDanzer]

You should use column strength calculation to determine rod requirements rather than depend on copying someone’s design that may have unknown limitations. Hiring a cylinder manufacture to design the cylinder for your specific application may be less expensive than if your design has problems. As a specialty cylinder manufacture and cylinder repair company, there are many poor design choices made that can lead to high maintenance and repair costs. Saving $20.00 in seal component costs can reduce the service life by more than 50%. Design style can double the manufacture cost of a cylinder, yet not improve the function.

Good luck

 

[kander]

EdDanzer,

Point well made. Perhaps best I leave it to the people that know.

I would still be interesting in getting my hands on a spreadsheet, or similar, that the cylinder manufacturers use to determine rod / bore diameters. Specifically for buckling.

 

[EdDanzer]

For buckling calculations you must have design specific information to have any true value. You can do simple calculation to get close. If you ask for a quote you may get different bore / rod diameters depending on the manufactures assumptions.