[jcolley]

Greetings,

I am looking to have some replacement gears made for an automotive component. The damage was identified just yesterday, so I have not yet drawn them up in CAD. I can provide these as samples or draw them up and attach here, but I am looking for a rough estimate for a batch of 10-20 pairs of these gears.

I am not sure if they are Nylon or Delrin, materials aren't me specialty.

I would like to have made the two gears (black and white) as well as the output shaft.

I realize this is little to go on, but hope to get a rough estimate.

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From someone who has beefed up their own r/c tranny to someone who wants to, I found the best was is to start with purchased components and modify them to suit your demands. I'm suggesting this to you and I have a 40,000 sq. ft. machine shop at my disposal.

[jcolley]

From someone who has beefed up their own r/c tranny to someone who wants to, I found the best was is to start with purchased components and modify them to suit your demands. I'm suggesting this to you and I have a 40,000 sq. ft. machine shop at my disposal.

If only it were that easy. My background as a kid was RC, but this is one of two throttle actuators manufactured by Siemens-VDO used to control 5 throttle bodies on a 507HP BMW S85 V-10 engine. These are a fairly common failure with less than 30,000 miles in some cases and replacement actuators are close to $900 with a good discount. Oh, and they usually fail in pairs.

Rather than watch guys continue to spend $2500 every 2-3 years, for a dealer to replace a poorly designed component, I'd rather try an alternative.

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Ahhhh please excuse my mistake. Without re-inventing the proverbial wheel, may I suggest you will get greater service life from a molded, glass-filled polymer than any machined plastic, especially with such small pitch diameters and load surfaces?

[jcolley]

No worries, Looking at the first pic, it does resemble an old RC-10 tranny...

Ideally, I would rather find a better alternative material as this one is clearly underdesigned. It would probably be fine for an engine used for racing as there is constant motion of the throttle bodies and that would spread the load across more of the teeth. But for the consumer application, where the engine is often hovering around 3000 RPM, the throttle butterflies are at a relatively fixed place, placing all of the load on 3-4 teeth. I suspect this is why the wear occurs only on those teeth.

Lubrication was minimal, but the cover for that gear casing has the electronics mounted to the inside of it, so metal on metal gear mesh would wreak havoc I believe. I even thought about brass input and output gears (the input is already brass) and a low friction, no lube, sacrificial gear in the middle.

[Finegrain]

Hello,

I would look at bronze for the small white gear, and a high-performance plastic for the large white and black sector gears. The damage to the small white gear is probably what precipitated the damage to the sector gear.

I cut gears regularly. I'd be happy to give you price quotes for these. In order to work up prices, I'd need to get a bunch of measurements off of the original gears, and have the actuator body on-hand, to verify center spacing in case the gears are not canonical involute.

Regards.

Mike Schetterer
Finegrain Metalworks
(425) 681-4732

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Too bad they did not design these to use miniature extra-light timing belts, eh??