Gear Types

[Lil' Lavery]

Any chance the rest of us can see the designs on those transmissions?


And yup, definately a spur gear.

[JoelP]

I read that you guys used 32 pitch gears. Why did you choose to use those over more common (as far as I know) 20 pitch gears? Advantages/Disadvantages?

[Joe_Widen]

How do you guys get those gears to stay put with out keys or set screws? I know you used hex stock on the final stage. I'm mainly asking about the gear on the Fischer Price.

[Travis Covington]

Originally Posted by Joe_Widen

How do you guys get those gears to stay put with out keys or set screws? I know you used hex stock on the final stage. I'm mainly asking about the gear on the Fischer Price.

Are you refering to the pinion or the driven gear? The pinion is mounted onto the CIM and AM planetary shafts using the supplied 2mm keyway with an internal spline retaining ring.

The driven gear is also a hex. The only other place we used a keyway within the gearbox was on the output shaft to retain the sprockets that go to the front and back wheels. There is no easy way to put a hex there, as much as I would have liked to.

As for 32 pitch vs 20 pitch, the 32 pitch at 3/8" face was far strong enough for the initial reduction off the motors and allowed for a more compact gearbox overall. The large 32 pitch gear is a 96 tooth, and the large 20 pitch dogged gear has 72 teeth. Both are relatively large, but allowed us to have only one intermediate shaft with no chain reduction.

[Dick Linn]

Travis, the gearbox picture you posted is a bit different than the original. Is this one a 2-motor version? Is there an additional red gearbox on this one?

I agree that the gears appear to be helical because of the moiré pattern. Look here and scroll down to the two photos. http://en.wikipedia.org/wiki/Nyquist...als_and_images

[Cory]

Originally Posted by Dick Linn

Travis, the gearbox picture you posted is a bit different than the original. Is this one a 2-motor version? Is there an additional red gearbox on this one?

I agree that the gears appear to be helical because of the moiré pattern. Look here and scroll down to the two photos. http://en.wikipedia.org/wiki/Nyquist...als_and_images

are you referring to the CAD image he posted?

If so, it's identical to the previous pictures, with the exception of color. the large gear on the intermediate shaft is blocking your view of the mounting holes for the second motor.

The AM planetary for the Fisher Price motor is not pictured, so that may be the source of confusion as well.

If you're referring to the actual picture in his earlier post, the FP is blocking most of the CIM. If you look closely, you can see the CIM under it.