Hydraulic drive, 2 wheel "mini bike" 1

MAragorn · Jan 24, 2007

Pardon me, this is WAY out of my field (HVAC design), but I have an interest in it.

Anybody familiar with the Rokon off road motorcycles? They are 2 wheel drive using (what appears to me) to be a pretty complex mechanical drive system.

It occurs to me that it would be much neater to use a hydraulic drive, separate motors for each wheel, driven in series, so that if one wheel is slipping, the Hp (?)/ torque (?) is available to the other wheel.

Looking at mini-bike design, they often use a "torque convertor", which seems to allow the speed of the bike to increase if the torque requirement drops.

I am trying to wrap my head around how this works with a variable speed gas engine driving through the "torque convertor" to a hydraulic pump.

Just so you get an idea of what I am thinking is a 5-8 hp motor with 25" VERY wide low pressure tires, resulting in a floatation type of situation that would be environmentally friendly to grass, etc.

Anybody have any thoughts?

thundair · Jan 24, 2007

I remember one of the Asian company's had a contest for their employs to come up with alternate forms of transportation and the winner was a hydraulic powered dirt bike.
I don't think it was a motorcycle company if it was then it was Honda.. This has got to be 15 years ago at least

You might find it with a patent search ...

http://freepatentsonline.com/4041922.html

I don't know anything but the people that do.

swall · Jan 25, 2007

I know a little about Rokons. I even rode one in Alaska in 2003.I believe the "torque converter" is similar to what is used in snowmobiles--basically a continuous variable transmission. It uses a v-belt and two pulleys. The pulley v spacing varies with engine rpm and this changes the ratio as the belt is free to move to a higher or lower point on the pulley faces.I think Rokon may also have a gearbox with a high and low range. Yes, a hydraulic drive might be a neat trick and you could add an accumulator or retarder to help with braking when descending steep hills.

MAragorn · Jan 25, 2007

swall

you are right about the torque convertor.

I have also considered powering this bike with a small diesel engine. Anybody know of a source for reasonably priced small diesel engines?

dgallup · Jan 25, 2007

I know Honda had a hydraulic drive trials bike years ago. It was rear drive only.

There was a lot of interest in 2 wheel drive racing off road motorcycles a few years ago. They were over-driving the rear wheel and letting the front free wheel in the forward direction. The idea was that it would behave like a rear drive in most situations but if the rear lost traction then power would transfer to the front. Like a lot of ideas, the extra weight, cost and complexity seems to have over powered the advantages.