Sat Jul 20, 2013
Found Gear Pump/Motor Parts Kits.
Gene - do you know more about the course on gear pumps from MIT? I should make friends with the professor.-MJ
Sat Jun 15, 2013
Concept: get two off-shelf gears and seals, build casing around it for Prototype 1 Open Source Hydraulic Gear Motor/Pump. Then derive fabrication procedures for larger scale versions, such as 100 cu in
We discussed some parameters, 14-28 GPM, 2000PSI, 50 HP input, 6:1 gearbox, 1 cubic inch displacement -26.5 ft lbs of torque at 2000psi with a 1 cubic inch/rev displacement motor, (displacement x pressure)/24pi Hyd motor speed is GPM= RPM x displacement /231 and typically gear pumps need at least 500 RPM to run properly.
Looking into gear design, the displacement is determined by the 2 gears center to center distance, gear width and gear OD. With this info you can use a calculator http://www.intlfpa.com/content_cal_gpmcalc.html and get the flow.
The actual flow from one side of the pump to the other does not go through the teeth but around the gear set. This is one critical tolerance, between the walls of the pump and the gears should be .00005, a gap, too big and lose volumetric efficiently, or too tight which generate heat.
An ideal could be a pump that has parts widely available due to patent running out, use gear set and repair kit for seals, machine to square steel blocks, sealed with oring and figure 8 wear plate to accept gears with .00005 tolerance and we should be able to use as a bi directional motor or as a pump.
After developing prototype, testing to include torque, leak, flow at pressures.
For a brief explanation of how gear pump works. http://web.mit.edu/2.972/www/report-gear_pump.html