Hello all,
I have yet to complete the internal arrangements for the ZB-1. I have turned back to working on the ZB-1/2. I really want to get this final end cap proto-typed, tested and certified by the end of the year. As a result I have spent a fair bit of time sanding and smoothing the end cap and the outer casing. However this was taken sideways by the decision that I took weeks ago to completely redo the shaft seal design.
Having a 4 mm shaft meant that I had to take a length of 6 mm stainless rod and machine a section of it down to the required 4 mm for the seal and the oil lite bush and then onto the brass coupling. The shaft starting off at 6 mm for the bore of the delryn plastic gears that I was using. Then it dawned on me, "why don't I just use a 6 mm seal and 6 mm oil lites?' This would be so much easier..DUH!!!!!!
This would mean next to no machining except a slight taking down of the shaft where it slips around the u cup seal. Why didn't I think of this earlier?
Old shaft, new shaft. Half the machining work, .more reliability and more surface area for a coupling to grip onto and just a more solid arrangement. Flat for brass outer coupling.
Drilling a 2.3mm hole in stainless is a pain. I have decided to use this shaft in all the end caps even the ZB-2 with the direct drive. This will streamline production.
The next step has been the redesign of the end "shaft support housing' at the very end. It did nothing. it was cosmetic and did nothing to hold the U cup seal in place and stop water coming in around the sides of the seal. So I took a long hard look at the designs that DM uses and decided to modify my own designs to press fit a 6mm U cup in place. What I found earlier in testing was that the old 4mm design was leaking as silicon was about the only thing holding the cup seal and place and stopping water from getting around the outside.
Seriously Crap set up.
So I got cracking with a material that I like using on the lathe, Delryn, also known as Acetal. This stuff turns down beaut and was ideal for getting the precise internal dimensions for making a housing that would press fit the 6mm U-cup, with an outer dia of 10 mm nice and snug.
So i have completely redesigned the internal parts of the seal minus the outside housing which was big enough to fit the adjusted parts. Now the silicon doesnt do the work of keeping the seal in place, the press fit outer support does. To make it even more cunning the inner support has a lip that fits in and under the outer support to give a little more sealing to boot!.. Nice...
More later.
David H
I have yet to complete the internal arrangements for the ZB-1. I have turned back to working on the ZB-1/2. I really want to get this final end cap proto-typed, tested and certified by the end of the year. As a result I have spent a fair bit of time sanding and smoothing the end cap and the outer casing. However this was taken sideways by the decision that I took weeks ago to completely redo the shaft seal design.
Having a 4 mm shaft meant that I had to take a length of 6 mm stainless rod and machine a section of it down to the required 4 mm for the seal and the oil lite bush and then onto the brass coupling. The shaft starting off at 6 mm for the bore of the delryn plastic gears that I was using. Then it dawned on me, "why don't I just use a 6 mm seal and 6 mm oil lites?' This would be so much easier..DUH!!!!!!
This would mean next to no machining except a slight taking down of the shaft where it slips around the u cup seal. Why didn't I think of this earlier?
Old shaft, new shaft. Half the machining work, .more reliability and more surface area for a coupling to grip onto and just a more solid arrangement. Flat for brass outer coupling.
Drilling a 2.3mm hole in stainless is a pain. I have decided to use this shaft in all the end caps even the ZB-2 with the direct drive. This will streamline production.
The next step has been the redesign of the end "shaft support housing' at the very end. It did nothing. it was cosmetic and did nothing to hold the U cup seal in place and stop water coming in around the sides of the seal. So I took a long hard look at the designs that DM uses and decided to modify my own designs to press fit a 6mm U cup in place. What I found earlier in testing was that the old 4mm design was leaking as silicon was about the only thing holding the cup seal and place and stopping water from getting around the outside.
Seriously Crap set up.
So I got cracking with a material that I like using on the lathe, Delryn, also known as Acetal. This stuff turns down beaut and was ideal for getting the precise internal dimensions for making a housing that would press fit the 6mm U-cup, with an outer dia of 10 mm nice and snug.
So i have completely redesigned the internal parts of the seal minus the outside housing which was big enough to fit the adjusted parts. Now the silicon doesnt do the work of keeping the seal in place, the press fit outer support does. To make it even more cunning the inner support has a lip that fits in and under the outer support to give a little more sealing to boot!.. Nice...
More later.
David H
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