Fisher price motor gear specs

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Posted by Nathan Kroll.

Student on team #68, Truck Town Terror, from Brandon High School and GM truck.

Posted on 7/12/2000 11:53 AM MST



Does anyone out there possibly have info. on the module, pitch, pressure angle or any other misc. information on the gear that is on the fisher price motors. This info. would be very helpful and greatly appreciated.
Thanks

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Posted by Amy .

Student on team #126, Gael Force, from Clinton High and NYPRO.

Posted on 7/12/2000 6:45 PM MST


In Reply to: Fisher price motor gear specs posted by Nathan Kroll on 7/12/2000 11:53 AM MST:



I've been drawing the Fisher-Price motor gears in Mechanical Desktop...I'm not certain, but I used 14.5 degrees as the pressure angle and it looks right on the screen...most gears are either 14.5 or 20 degrees.

Amy

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 7/13/2000 8:49 AM MST


In Reply to: Re: Fisher price motor gear specs posted by Amy on 7/12/2000 6:45 PM MST:



The gears are all standard, full depth, 20 degree pressure angle, English pitch gears.

The gears are slightly modified to help them with strength & mfg. issues, but it is my understanding that the modifications are not too signifcant (they will all run fine with standard steel gears).

A tip for getting the Diametral Pitch of full depth gears:

DP = (Number of teeth + 2) / (Outside Diameter of the Gear)

I have not looked at the gears in a while, but I recall that the pitches are 32 at the motor pinion and 20 at the output gear.

I suppose that the intermediat gears are 24 pitch as that is the only common English D.P. in between 20 and 32.

Good luck.

Joe J.

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Posted by Joe Johnson.   [PICTURE: SAME | NEW | HELP]


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.

Posted on 7/13/2000 10:05 AM MST


In Reply to: 20 Degree Pressure Angle posted by Joe Johnson on 7/13/2000 8:49 AM MST:



Oops!

The final output stage of the Fisher Price is 16 DP not 20 as I had recalled.

Knowing this, I suspect that the first stage is 32 pitch (the motor & its gear). The second stage I guess is probably 24 pitch and the 3rd stage is prabably 20 pitch, with the final stage being the 16 pitch gears.

Just my best guesses without having the gearbox in my hands.

Joe J.

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Posted by James Jones.

Engineer on team #267, The Demolition Squad, from North Broward & St Andrews and Motorola.

Posted on 7/13/2000 11:07 AM MST


In Reply to: 20 Degree Pressure Angle posted by Joe Johnson on 7/13/2000 8:49 AM MST:



The gearboxes for 267 were designed setting the gear center distances to line on line for pitch diameter. The drills and all the purchased gears worked fine with a tiny bit of backlash. The FP motors (used by themselves) however needed to have the center distances openned up I'd say .005 to .010. I never was able to figure if this was a manufacturing problem but this happened with 2 set of parts so I suspect not. Just something to be aware off. Next year I'll accept some additional lash and make the design a little less sensitive.