Attaching wheels to wiper motors

You will find all kinds of connectors and U-joints through McMaster Carr

snipped-for-privacy@yahoo.com wrote:

I've done this in the past....

Plastic wheels (lawn mower sort of thing)- Press a nut into the bore of the wheel, then screw the nut and wheel onto the shaft. Works OK with light loads, but use thread lock or similar or the wheel & nut unscrews itself very easily.

With metal wheels - (caravan jockey wheels) I've welded a nut onto a large steel washer (carefully so as not to damage the threads) then weld the washer to the center of the wheel. This is very strong and reliable but the wheel can unscrew itself under heavy load. Another option is to not weld the nut to the washer but to use it to bolt the washer (and wheel) onto the shaft, this is only feasible if the wheel shaft is of sufficient diameter to get a long reach socket spanner in there.

For heavy loads, fasten a flat steel sprocket onto the shaft (you might want to taper the hole to suit the taper on the shaft) with a nut. and drive the wheel via a chain. That way you can carry a lot more weight on the wheel. bicycle chain can deliver a lot of power and is easy to get hold of, along with tools for splitting and joining it. I've used this technique in the past to drive wheels varying from 6inch jockey type wheels to 15 inch bicycle wheels.

If you have the facilities, it's relatively easy to replace the shaft with a longer one on a lot of wiper motors (well at least the ones Ive used here in the UK). If you remove the plate from the rear of the gear housing. The shaft and the nylon gear wheel are often held in place with a 'C' clip on the shaft under where the nut goes. Once the clip is off, a slight twist to disengage the worm gear should bring the shaft and gear out. Clamp the shaft in a vice and use a hacksaw to cut through the Nylon of the lump on the back of the gear wheel and the end of the shaft. Try not to damage the gears. With care you should be able to push out the shaft (it's splined so don't try to twist it. you will need to use your vice as a press) the resulting hole may need to be carefully reamed out to suit a piece of 'bright' bar the same size as the original shaft. Drill 2 or 3 3mm holes through the side of a large 'repair' washer then weld it onto the shaft. Slide the gear onto the shaft and drill through the holes in the washer and fit some nuts and bolts through to clamp the gear to the washer. I usually leave some shaft out through the back of the gear and drill a hole in the cover for it to come through (handy if you want an encoder on the back or two wheels driven from one motor. Put a strong(ish) compression spring onto the shaft before fitting the modified cover and it will serve to keep the gear in place without trying to fit a 'C' clip again. I've done this mod with a wheel at each end to replace the pedals and chain in a childs ride on toy. It gave about 3 years reliable service, being ridden by my child over uneven ground and often with a friend being pulled along in a traailer behind...

I don't claim to be an expert on this just my experiences to date. I have never had access to lathes and milling machines for this sort of thing, so a vice, hacksaw, small welder etc are all I've ever needed.

Hope this rambling helps :-)

Jon Sutton.