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Small Hydraulic Pump and Motor

Small Hydraulic Pump and Motor

Small Hydraulic Pump and Motor


I am looking for a small hydralic pump and motor. The pump drives the motor by some direct oil lines between the two. The pump must around 3" in diameter and 3" long (a cylider, and the smaller the better). The motor may be 4" or 5" in diameter but only 2" long (a cylider as well, again smaller the better). The pump will rotate at low speeds, roughly 60 RPM to 300 RPM. The motor will run around 1RPM to 10RPM. The power being supplied to the pump will be around .5HP at best (probably around .2HP on average) The motor must deliver a high torque output. It is also needed that the pumps will have the drive shafts exiting both sides of the pumps so they maybe driven/drive from either side. Has anyone worked with or heard of pumps/motors these small with such low operating speeds? I have looked at many sites on the net and asked many suppliers and am still lost. Thanks to anyone who can help.


RE: Small Hydraulic Pump and Motor

Whups, my bad..

The Motor will run from 60RPM to 300RPM as well.

RE: Small Hydraulic Pump and Motor

confused.  if the pump runs from 60-300 rpm and themotor runs 60-300 rpm, you are not getting any increased torque from speed reduction.

Other than relocating the power, are not you simply connecting themelectric motor to the load?

RE: Small Hydraulic Pump and Motor

Sorry about the confusion. What I am trying to achive is basicly a small drivetrain. The pump will be powered by myself via a crank. I am going to control the speed of the motor for the output by a set of valves and a proportioning system. I would like to select settings for either high speed, or high torque, depending on the load needed for the output. If I need high torque obviously it will be at low RPM for the output motor,  for high speed output it will be low torque. This of this just like vehicle drivetrain, but all hydraulic instead of gears.

RE: Small Hydraulic Pump and Motor

Since the power is supplied by a hand crank then you will probably want a piston pump.  I don't think that gear pumps would be efficient enough.  I think that I would down grade the pump RPM to no more than 120, unless you are going to have a gear increase from crank to pump.  

What kind of a load are you going to be moving?  That will govern the pump and motor displacement.  And, of course, the physical size of the pump and motor.

Have you considered strictly mechanical linkages?  

From strictly volumetric considerations the pump motor displacement would be 60:10 or 1 unit for pump and 6 units for motor.  Other side of range would be 300:1.  I think that you should pick an operating condition so that some figures can be nailed down.

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