Swash No Buckle

A bit earlier I was asked to gather up some information about pump pressures with regard to the angle of the swash plate. Now not being an engineer, this term went straight over my head and so Hughie, the MD very kindly took some time to show me what this meant.

I had seen plenty of hydraulic system drives (the bit that that turns engine revs into hydraulic oil being pushed around the system) but had never known how one worked. I am pleased to say that now one more of the many wonders of hydraulic engineering has  been revealed to me, and very interesting it is too!

Basically a circle of cylinders and pistons connected to an angled plate spins. Both the cylinder block and the angled 'swash' plate spin at the same time so the swash plate pulls the pistons in and out as each cylinder/piston moves around the circle. The changeable angle of the plate determines how much the pistons actually move in and out for each revolution.

The pistons moving away from and out of the cylinder block are drawing hydraulic oil into those cylinder while the ones moving back into it are pushing the oil out, having brought it around to the other side, and so oil is forced to move continuously from one side to the other. Ingenious!

Seeing (and have a play with) the cut away working demonstration one above really helped me to understand what was going on. So now next time someone talks about the angle of the swash plate, I'll know what they mean.