|
There will be contious friction losses from pumping the oil, but it could be done by mounting a tank of hydraulic oil well above the motor (to gravity flow the oil to the motor (which would be acting as a pump), and keep air out of the system), and plumbing the lines from the motor into the tank, so oil is always circulating. You would have a valve in the output line from the pump to the tank, and when braking is needed, the valve would be partially or totally closed to slow or stop the flow of oil, which would stop the wheel also. Potential problems: 1.) If there is much mass (weight) to the vehicle at all, there needs to be a pressure relief system, as sudden closing of the valve would build HIGH hydraulic pressures that would probably damage or break something. 2.) For braking in reverse, you would need a second valve, as the other line from the pump to the tank would now be the "pressure" line. 3.) This system would not be suitable for holding the vehicle on a slope, as the motor will "creep" as the oil slowly leaks past the gears or pistons in the motor. If you are talking about building a small lawn-type vehicle, have you considered using a hydrostatic drive from a garden tractor? Cub Cadet hydros often sell on ebay in the $10.00 to $100.00 range. However, there are some problems there, too, as you'd need an oil tank, and someway to seal the output shaft from the hydraulic motor. (Unless you used the whole transaxle.) Search on ebay for "cadet hydro" or "Sundstrand".
|
