I have this 37D motor Pololu - 131:1 Metal Gearmotor 37Dx57L mm 12V (Spur Pinion) I have the wheels and mounting hub for it for it. How could I make a hole in a plastic body that when I put the shaft of the motor through it, The plastic body would be water proofed.
Hi,
First off, I do not know of a way to seal a D-type output shaft, but if you can couple it with a regular round shaft, a shaft seal will work.
I am on a robotics team that has, in the past, waterproofed homemade motors using shaft seals.
A shaft seal is basically a o-ring that is attached to outer material that fits inside of a hole. Here is a shaft seal image: http://nutrixtractor.com/images/MotorShaftSeal.jpg . Usually the outside diameter is about 1/2in, with a variety of interior hole sizes.
To install these, you would bore a hole in you plastic that does not go all the way through, but is deep enough to accommodate the depth of the shaft seal. Then grease the motor shaft and shaft seal with silicon grease or similar sealant to increase waterproofing, and push in the shaft seal. This method of sealing will completely waterproof a motor shaft.
You can usually find shaft seals at most hobby shops, especially ones that sell model boats. Also, depending on how far away the motor is from what you are turning, you might consider adding a bearing to keep the shaft straight and inline with whatever you are doing.
njs552
I don't know if anything is perfect or permanent. You might try a [u]grommet[/u] (which you can get from an electronics/electrical supplier or hardware store) greased with waterproof grease, or you can look for a [u]Radial Shaft Seal[/u]. If the motor is submerged, I think it gets difficult because it there is any seepage at all, it can never dry-out. But they do make submersible well-motors, so is must be possible to make something that stays sealed for a few years.
Depends on the pressure differential - maybe a stuffing box.
I'd ask on a modelling forum.
hi.
Looking at the drawing you have 3.5 mm to seal with.
Get a 6mm ID 12.5mm OD 3.25mm O ring.
A rough drawing is attached.
Make the fixing plate from Delrin or Acetel.
Btw how water proof you looking for as in depth ??.
Besy of luck.
Regards Antony
Pololu motor.bmp (742 KB)
Use lots and lots of silicone.