Crosshead Engine & Crosshead Slider Design
Crosshead Engine & Crosshead Slider Design
(OP)
I've been handed a design job that involves designing the cranktrain for a crosshead engine (think large ship engine type arrangement).
The one area of this where I have no previous experience is designing the crosshead & slide mechanism so I'm hoping that someone might be able to point me in the direction of some references that google hasn't found for me.
I'm interested in all design aspects of the cross slide, including contact pressure, sliding velocity limits/issues, running clearance, clearance adjustment mechanisms and lubrication. I'm assuming that a well designed cross head will run on an oil film (while its moving, the oil film may well collapse when everything changes direction at TDC & BDC), does anybody have any idea whether its necessary to inject the oil into the middle of the bearing/contact area or can you just spray it onto the slide rails and let the cross slide run over it?
We're also designing the crank train, the stroke and engine speed are already defined so the mean piston speed is out of my hands but we can influence the cross slide motion and thrust loads via conrod length.
Any experienced comments or suggested references will be greatly appreciated.
Thanks.
The one area of this where I have no previous experience is designing the crosshead & slide mechanism so I'm hoping that someone might be able to point me in the direction of some references that google hasn't found for me.
I'm interested in all design aspects of the cross slide, including contact pressure, sliding velocity limits/issues, running clearance, clearance adjustment mechanisms and lubrication. I'm assuming that a well designed cross head will run on an oil film (while its moving, the oil film may well collapse when everything changes direction at TDC & BDC), does anybody have any idea whether its necessary to inject the oil into the middle of the bearing/contact area or can you just spray it onto the slide rails and let the cross slide run over it?
We're also designing the crank train, the stroke and engine speed are already defined so the mean piston speed is out of my hands but we can influence the cross slide motion and thrust loads via conrod length.
Any experienced comments or suggested references will be greatly appreciated.
Thanks.





RE: Crosshead Engine & Crosshead Slider Design
http://www.lindsaybks.com/
Mike Halloran
Pembroke Pines, FL, USA
RE: Crosshead Engine & Crosshead Slider Design
http://www.youroldtimebookstore.com/product-p/4104...
Mike Halloran
Pembroke Pines, FL, USA
RE: Crosshead Engine & Crosshead Slider Design
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Crosshead Engine & Crosshead Slider Design
B.E.
You are judged not by what you know, but by what you can do.
RE: Crosshead Engine & Crosshead Slider Design
B.E.
You are judged not by what you know, but by what you can do.
RE: Crosshead Engine & Crosshead Slider Design
the only splash lube engine i have experience with is ajax.
RE: Crosshead Engine & Crosshead Slider Design
B.E.
You are judged not by what you know, but by what you can do.
RE: Crosshead Engine & Crosshead Slider Design
Mike, I've purchased a copy of the book you suggested and its fairly interesting but a little vague on design limits. The way the old timers laid out equations is very different to what is taught nowadays (well, relatively recently anyway).
Question for Greg Locock, why do you think it is risky to locate the oil supply in the high pressure area? Is this a concern that the hydrodynamic forces would stall the delivery flow or that you could get errosion opposite the feed point at TDC & BDC? I've recently seen some examples of bearings with shallow grooves around the oil supply point to help distribute the oil, I think these could help prevent both of these issues.
Thanks.
RE: Crosshead Engine & Crosshead Slider Design
That being said analysing bearing pressures is a known art, it just needs doing properly. Worst case scenario is you build a single cylinder engine and install pressure tappings at likely points around the circumference.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Crosshead Engine & Crosshead Slider Design
Mike Halloran
Pembroke Pines, FL, USA
RE: Crosshead Engine & Crosshead Slider Design
Some engines I've worked on have used telescoping tubes to the crosshead which also supply oil to a cooling circuit within the piston rod and piston crown. I believe other manufacturers use a swinging pipe arrangement.
I don't recall whether oil was sprayed or applied directly, but being as the slides are within the sump enclosure it shouldn't matter, so long as spraying is with large enough droplet sizes to avoid oil mist generation.