Can a pinion move axially on a crown gear? 2

[tdougher]

Is it possible for a pinion to move axially on a crown gear? I am looking for a constant input speed and variable output speed (even a small variation) by moving the pinion. What problems need to be considered? Would this work in high HP applications such as automobile drivetrains? Could someone recommend resources for further research?
Thank you,
tdougher

 

[sreid]

The speed of gear trains is fixed and set by the number of teeth on the gears. Axial movement of the pinion would only change the clearance.

 

[Heckler]

I'm assuming you are using a crown spline because of alignment issues? What is the delta elevation between both centerlines? Another issue would be to maximize tooth meshing. Give us some more detailed information.

http://www.omnigearandmachine.com/technical_information.htm

http://www.drgears.com/

 

[tdougher]

The crown gear is not required. My goal was to transmit a large load with gears only and vary the output speed slightly. The 'gears only' requirement is for a large load and to minimize the losses other variable speed devices incur. As sreid points out, the numbers of teeth fix the ratios. I thought a variation in clearance or point of contact between gears would slightly change the ratio. I don't have details since this is just an idea and apologize for my lack of knowledge in this area.

 

[Heckler]

If you're trying to transmit a large load you will want opitimize tooth contact othewise you will shear teeth. You can expect a mechanical efficiency of drive gears to be between 0.75-0.85. You might want to start doing some research on gear train design. Best of luck

 

[sreid]

One way to accomplish what you want to do is through differential gearing. This is probably easiest to undestand by picturing the rear axel of a rear drive automobile. Jack up one wheel so it is off the ground. This wheel will run at twice the RPM of the rear end "Crown wheel." Now attach the wheel that was on the ground to a variable speed motor connected through a large gear reducer. The RPM at the output shaft of the gear reducer will add or subtract RPM from the wheel that is off the ground.

 

[EnglishMuffin]

You might be able to do what you want by using a friction drive, and these can be designed for high horsepower applications, but this is probably not what you are looking for. There are also PIV drives with variable pitch chains, which have been used in automobiles.