gear surface contact and torque

[reggy]

I have seen it written a few times now that a wider main gear, which naturally provides more contact with it`s pinion gear, providing the pinion gear is as wide as the main, will produce more torque than a narrower set of gears of the same diameter.

I could never understand why.....and always thought that torque was dependent on the gear ratio.
Can anyone explain in reasonably simple terms, the reason for the extra torque with wider gears, if it is indeed true?:-?

[nigelr]

Dunno reggy, would come down to the relative number of teeth on the gears, wouldn't it?
Gawd, reminds me of the public service exam I did forty years ago...............

[reggy]

Dunno reggy, would come down to the relative number of teeth on the gears, wouldn't it?
Gawd, reminds me of the public service exam I did forty years ago...............

Yeah , sorry mate...we need one of those ginger beers.

[benno_r]

Mechanical Ginger Beer speaking here...

The only advantage to having wider teeth, would be to spread the forces generated during teeth meshing over a greater area. This lowers the pressure that are put on the gear, reducing wear. Or alternatively, you would be able to apply more torque to the gearing while keeping the same pressure on the teeth.

Most gears in fishing reels don't mesh across the full width of the tooth anyway, so making them wider is fairly pointless. Exceptions would be on higher end reels ie Stella, Saltiga and others.

(Note: my field is not power transmission, so feel free to correct me if I am wrong)

Cheers,
Ben

[reggy]

Mechanical Ginger Beer speaking here...

The only advantage to having wider teeth, would be to spread the forces generated during teeth meshing over a greater area. This lowers the pressure that are put on the gear, reducing wear. Or alternatively, you would be able to apply more torque to the gearing while keeping the same pressure on the teeth.

Most gears in fishing reels don't mesh across the full width of the tooth anyway, so making them wider is fairly pointless. Exceptions would be on higher end reels ie Stella, Saltiga and others.

(Note: my field is not power transmission, so feel free to correct me if I am wrong)

Cheers,
Ben
Thanks Ben
So wear on the gears is reduced, but it would not reduce the force needed to wind in a given weight, would it?

[Horse]

Thanks Ben
So wear on the gears is reduced, but it would not reduce the force needed to wind in a given weight, would it?
The way I see it the gear diameter. ratio and force applied are the variables in the torque. A wider face on the gear results in less pressure applied to each unit of area of the gears contact face if the gears were perfectly machined. In most cases wider gears mean a stronger and more wear resistant system

[benno_r]

Thanks Ben
So wear on the gears is reduced, but it would not reduce the force needed to wind in a given weight, would it?

No it wouldn't. Gears are simply a torque multiplying system. If you want to reduce the winding force, get a longer handle. For a constant torque value, as the length of the handle increases, the winding force decreases.

The down side to this, is if you really lean into it, you create extra torque which "may" overload the drive train.


The way I see it the gear diameter. ratio and force applied are the variables in the torque. A wider face on the gear results in less pressure applied to each unit of area of the gears contact face if the gears were perfectly machined. In most cases wider gears mean a stronger and more wear resistant system

This is the non-engineering answer to my first post - much more succinct!! haha

Cheers,
Ben

[reggy]

Thanks Ben!

[Brent_P]

If you want to reduce the winding force, get a longer handle.

Like Archimedes said "Give me a lever long enough and a fulcrum on which to mount it, and I shall move the world".

Reggy,

Alternatively, if you can't find a longer handle for your overhead, you could try only half-filling the spool with line ;D .

The radius of anything that rotates about it's axis can be thought of as a lever, including the radii of gears and reel spools. For jigging, I use a Daiwa Saltiga Lever Drag LD20HS, which has a retrieve ratio of 7.3:1. When people on charters ask me about the high gear ratio, they usually say something like "Bloody hell, that would be hard to wind". I say no, it's not, because the spool is tiny and the handle is long, and the handle length / spool radius ratio is much higher than on a larger overhead reel (no one wants to wind a foot-long handle, even on a large reel). Unfortunately, only the two-speed version of this reel (high 6.3:1 / low 3.1:1) is available in Australia, probably because of the misconception that a reel with a 7.3:1 retrieve ratio MUST be hard to wind under load (or too 'fast').

Talking about levers, you'd be surprised how many times I've heard and read people say something like "20kg of drag? That'd be easy. I can lift 20kg's easily!" Yes, of course, but try holding a six-foot-long pole at one end and attaching the 20kg weight to the other. It wouldn't be easy to lift. It's interesting how many people don't understand the basic principle of leverage, when it is as evident in everyday life as gravity.

Sorry if I got slightly off topic there...

Brent.

[reggy]

Hi Brent
Yes, one thing to be careful about with high gear ratios and long handles is the possibility of damaging the pinion gear. I guess that`s why they make 2 speed reels for heavy winding.
Actually I prefer to have a large diameter spool with a low gear ratio like my Jigging Masters.
This way I don`t worry about stressing my gear train.

[Brent_P]

Hi Brent
Yes, one thing to be careful about with high gear ratios and long handles is the possibility of damaging the pinion gear.

Hi Reggy,

Yeah, that was my main concern (along with the anti-reverse) when I bought the little Saltiga, but it has a stainless steel pinion and drive gear (like the Jigging Masters), so I hoped they'd hold up. I've used the reel for two jigging 'seasons' now and caught a lot of kingfish, and it still feels like new. I fish it at 8.5kg of drag, which is about the highest I can set it (at full) before the 'handle binding' makes the reel unfishable.

I am seriously considering buying a Jigging Master PE4, mainly because of the incredible amount of drag this little twin-drag reel can produce without handle-binding issues, but with my jigging style the relatively low gear ratio and small diameter spool would mean a lot of extra winding.

Cheers,
Brent.

[reggy]

I have a PE5 narrow...spool is 64mm diam. (not really a small spool) and 25mm wide....you would love it.