eSprite: Transmission-Motor Adapter & Coupling

After completing the design of the motor-to-transmission mounting plate, I sent it along to OSHCUT to have it manufactured. It came out great! This was the first time that I’ve contracted out to have a part like this made. Usually I’d whip out the angle grinder and the milling machine to make a simple part, but I decided against it because I have both limited time and the desire to possibly make more of these conversions in the future. With a pattern that has been successfully contracted out and created by someone else, I can be assured of easy future creation of the part. 

And here it is in place on the transmission!

The other part that I’ve been looking at during this time is the motor-to-transmission-driveshaft coupler. I decided to go with a simple clamping coupler over a flexible coupling for the reasons of cost and ease of manufacturing. I may find that in the future it is better for a flexible coupling with a rubber damper to be installed, but that is for another day. To prove out my design and construction abilities, it’s simple enough to go with a rigid coupling.

To pick up the splines of the driveshaft I cut out the central portion of the clutch plate I had removed during the engine ripout. After some grinding it was in hand with a bunch of score marks. I picked up the dimensions of the spline in case the next step destroyed the piece. In order to remove the defects (self-imposed..) and allow the spline piece to fit in the coupler, I would have to turn down the outside!

To cut the spline piece’s outer diameter to size I turned down a piece of sacrificial stock steel to 0.725” (the inner diameter of the spline) and slipped the spline piece over it. I used two nails as wedges to create a friction lock between the sacrificial steel to make it turn as a unit. I then turned down the outer diameter to 1.250”, drove out the wedges, and put the spline piece in the coupling for power transmission use! Fantastic!

Here are some additional views of the coupler and transmission plate all together. The two pieces (spline-coupler) are an interference fit of .002-.003″, so I had to cool down the spline to fit it in and then press!

Besides some other minor part removal (windshield wipers, clutch & brake pedals) I haven’t accomplished much since the last update.

I intend on wiring up the control boxes very soon still. I think I’ll have the time to do so between Christmas and New Years, but we’ll see!

Published by lombardiengineering

Always striving to be an all around great individual

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