Biggadike
Mechanical
- Mar 12, 2002
- 128
I'm struggling with this one..
I've got a sprung loaded pull lever (for a switch) the motion of which is governed by a pin in a slot profile. (This provides detents and self centring etc.) The environment is difficult (unsealed unit on landing gear of aircraft) and I'm having problems with galling on the 4mm dia pin - I can't use lubicants (attract dirt- washes off etc.) I need the pin to slide accross the angled slot surface under the load of the spring.
I've tried:
Phosphor bronze pin onto chemically polished stainless.
(Failed quite quickly)
Stainless steel pin onto chemically polished stainless - both suface treated with oil impregnation.
(Much better but failed at about 15k ops)
I need at least 40k ops - low temp performance (-55dgC to 80degC).
I don't want a little bearing in there as dirt and dust will cause problems.
I would love to use a machined plastic for the slot carrier but delrin will creep (constant load from spring) and glass filled will abrade the pin.
Any suggestions?
I've got a sprung loaded pull lever (for a switch) the motion of which is governed by a pin in a slot profile. (This provides detents and self centring etc.) The environment is difficult (unsealed unit on landing gear of aircraft) and I'm having problems with galling on the 4mm dia pin - I can't use lubicants (attract dirt- washes off etc.) I need the pin to slide accross the angled slot surface under the load of the spring.
I've tried:
Phosphor bronze pin onto chemically polished stainless.
(Failed quite quickly)
Stainless steel pin onto chemically polished stainless - both suface treated with oil impregnation.
(Much better but failed at about 15k ops)
I need at least 40k ops - low temp performance (-55dgC to 80degC).
I don't want a little bearing in there as dirt and dust will cause problems.
I would love to use a machined plastic for the slot carrier but delrin will creep (constant load from spring) and glass filled will abrade the pin.
Any suggestions?