(mechanical) Power transmission question (and seal advice)

[ramses]

I'm looking for a cost effective way to reduce the speed of a rotating shaft by a factor of 13.5. Shaft will be rotating at 7000 RPM tops, at constant torque.

General requirements:
synchronous power transmission.
~10 HP
multistage okay

from what i can see, I have a few options: spur gears, helical gears, timing belts, or possibly roller chains. Roller chains are generally limited to slower speeds, but are used in racing go karts with engines that redline at 7100 RPM. Would it be possible to use the sprockets and chain designed for a kart for this?

Also, how much torque do you think these gears can take? Do you think they can be used at 3000 RPM output (driving the carrier, 3000 RPM out the sun gear)

Thanks

[jrrdw]

What are you building and what weight/stresses will be involved? Never underestimate roller chain, tough stuff. As for that gear, again it depends on what you ask of it. It's made for electric bikes and alike so it will handle a fair amount of stress.

[Technician1002]

May I recommend a VFVV drive for the motor?

http://multyremotes.com/remote-control-ac-drive.htm

[ramses]

May I recommend a VFVV drive for the motor?

http://multyremotes.com/remote-control-ac-drive.htm

You could suggest it, but I'd advise against doing so. It may interest you that a computer engineer also suggested AC servos. He even offered me some huge 3 phase ones (that I had no possible way to drive)

This is for the valvetrain (etc.) of a a rather special engine. all operation will be fairly smooth, except the cogging of injector pumps and the like. That should be dampened by inertia fairly well.

I also believe the gears could take it, I just wanted a second opinion.

With regard to the roller chain, I was mostly concerned with the speed of the chain, rather than the load capacity. After all, larger ones are used on motorcycles, which can put out 20x the power I need.

[Technician1002]

If this is for a valve train for a special engine, wouldn't a timing chain be in order to provide synchronization of the engine and it's valve train? I presume you are needing variable valve timing. To do variable valve timing, a rotary hydraulic cylinder in the valve drive shaft can advance or retard the valve timing as needed and adjusted on the fly by hydraulics.

If this is for a classified prototype send me a PM. Other options include direct drive electric valves instead of cams, or electric cam advance instead of hydraulic.

In regards to chain drive and higher speeds, the Prius car is chain drive. What speeds do you need?

A chain on a sun gear at 3000 RPM should be no problem. Small gas engines run at 3600 RPM on a regular basis. This is the standard speed of small portable AC generators for 60 HZ output.

[ramses]

Rather than make a new topic, I'll just add to this one. I am now in need of a way to seal a "rectangular" portion of a cylinder with a matching rectangle. There is a port on the circumference of the outer sleeve that must be sealed except when it is aligned with a matching port on the inner cylinder. This needs to support a wide, high temperature range, high pressures, and high surface speeds (3000 RPM ideal).

I considered making it a tight fit and forcing oil, but that would likely leak into the ports. some kind of dynamic gasket seal would be ideal.

Thanks (again)