Standard Cylinder Sizes 1

[PNachtwey]

I am looking for a table of standard cylinder sizes, bore and rod diameter for mm and inches.
I have found a table of ISO/metric cylinder sizes but it doesn't seem to cover cylinders with a bore over 200mm
The same goes for US/British units.
The ISO sizes do seem rather consistent with two options for ratios of the area. One option is the rod size area is about 70% of the cap size area. The second option is a rod size area of about 50% of the cap side area. I could simply just apply the same to the cylinders sizes in inches I know about like 2, 3.25, 4, 5, 6, and 8 but I know that presses use much bigger bore cylinders.

I am writing a program to compute cylinder sizes using the criteria I have written about in the H&P magazine.
The metric version is done but I had to extrapolate for bigger cylinder diameters.

It seems to me that once the cylinder bore are 6 inches or larger there is no standard and lots of options are available.
Much seems to be manufacturer dependent.

The problem I am trying to solve is that one can calculate the minimum cylinder diameters but reality is that one must chose the next size up that is available. I need a table of cylinder bores and rod diameters so I can find the next size up.



Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[akkamaan]

Cylinders, pistons and rods can't be more standard than the market of hydraulic seals. I would start with looking into a seal manufacturer like Trelleborg.

 

[RobertHasty]

Could you use manufacturer's datasheets below (but it's only up to 400 mm):

https://www.duplomatic.com/assets/SchedeTecniche/GB/71200.pdf

http://www.petr-hanz.com/ATOS/B241-ENG.pdf

http://www.utah-hydraulique.com/wp-content/uploads/2016/04/re17335_2016-01.pdf

It's only up to 400 mm...

 

[PNachtwey]

Robert, thanks. That allows me to confidently expand my table to 400mm.
What I am thinking about doing is rounding up calculated cylinder sizes to the next 25mm for sizes over 400mm.
I will do the same for cylinder sizes over 16 inches.
I will round up the rod diameters too when the cylinder diameters get to be that big.





Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[PNachtwey]

I have not found any data for cylinder sizes over 200mm except the one Bosch-Rexroth table. I have noticed that the Bosch-Rexroth rod sizes are not the same as the ISO sizes in all case. In addition, Bosch-Rexroth has extra sizes in between the ISO sizes and extend baore size to 400mm which is just short of 16 inches. Am I to assume that everything over 400mm is custom made?

Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[Stick.]

I just found a table from Eaton for cylinders going up to 20 inch bore:

https://eaton.partsolutions.biz/pdf/pct_1174013.pdf

, but I'm not sure how standard those sizes are. If I had to guess, I'd say that you're probably right that the larger sizes are going to be custom made, so above a certain size you may only be able to compute some minimum requirements for quoting purposes.

 

[RobertHasty]

Hi Peter,

I've just seen your post. My email sent the notification to spam.

It seems to me that you are right, that all these cylinders over 320 mm are custom made.

The standard which can be found in manufacturer's datasheets is ISO 6022, and I've found a link to the preview of that standard:

https://www.sis.se/api/document/preview/906963/

Page 6 mentions bore sizes in a range from 50 to 320 mm.

Best,
Robert

 

[PNachtwey]

The Bosch-Rexroth table of cylinder bores seems to cover a wider range than the ISO table of cylinder bores. However, the Bosch-Rexroth seems to use bigger rod sizes for the minimum rod size than the ISO cylinder bore tables. What I have noticed about the ISO table is that the standard size has a area ratio of 5/4 for the standard sizes. The Bosch-Rexroth table is closer to 5/3 because of the bigger rod but the Rexroth table is is less consistent in the ratios.

Question/opinions:
Which table to use?

When designing a press. the cylinder bores will often exceed those in the table. My cylinder sizing program calculates a cylinder bore size but it must be rounded up to some size that will be made. What increments should I use? 20mm, 1 inch, 2 inches?

Another option is to simply report the bore size that is necessary like 833mm and the let the user chose the next size up. I would also need to report the rod size and ask the user to round that up too. Then I can calculate the valve size.

I could simply ditch the whole table idea and force the user to pick the next higher bore diameter and lower rod size.


Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[hydtools]

I would ditch the table and let the user decide after you give them the calculate size. It would require the user to be more involved, which is a good thing.

Ted

 

[Stick.]

I agree with hydtools that getting rid of the table for large sizes makes sense. Those cylinders are likely going to cost enough that a little extra time spent to get it right won't hurt anything. It may be beneficial to allow the user to input the bore and rod sizes of cylinders they're considering to more easily check if they will still work or how far they deviate from the ideal cylinder. I'm mainly thinking of comparing cylinders with different bore and rod sizes where the area on the rod side isn't obvious.

 

[PNachtwey]

OK, I will let the user round up the cylinder bore and rod size. I will need to recheck the calculations to make sure it meets all my criteria. This will actually reduce code for the calculation part but add code for the user interface but its no big deal.

Thanks guys.


Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[TimSchrader2]

Hello

If you need a standard for the calculations, I have used references found in ABS standards as back up for calculations that need to be approved. For the end plates and other components. For any size cylinder. But these use alot larger safety factors then standard industrial customers making them more expensive.

 

[PNachtwey]

Tim, I am not designing cylinders. I am trying to make a program that will help people select the correct size cylinder, valve, accumulator and HPU for a given hydraulic servo control project.

Peter Nachtwey
Delta Computer Systems

http://www.deltamotion.com

http://forum.deltamotion.com/

 

[TimSchrader2]

Hello PN. I sort of thought so, but threw that out there anyways.

One factor that may be revalent in chosing cylinder size is wether it is a push pull or pull only cylnders. For longer strokes with a push cylinder the rod must be a larger diameter and have a certain spacer inside to limit loads on the bearings. And more importantly the euler buckling loads. There are rules of thumb for this. The larger rod can sometimes or even often drive the cylinder to the next diameter. Your probally already aware of this.