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Worm Reduction Gearbox

03/10/2016 1:53 AM

I have a 1:10 worm reduction gearbox running with 1450 rpm input speed. The output rpm is to be increased. I have exhausted options to increase teeth of output sprocket. Can I increase input rpm of this gearbox to 1800 rpm?

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Guru
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#1

Re: Worm Reduction Gearbox

03/10/2016 4:02 AM

In principle, increasing the number of teeth on the output gear reduces the output shaft speed.

<...increase input rpm of this gearbox to 1800 rpm...> It is not possible to say without knowing the gearbox in question, and this information has been withheld from the forum. However, the original equipment manufacturer can certainly advise and the matter is best resolved by discussion directly over the telephone.

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#2

Re: Worm Reduction Gearbox

03/10/2016 6:23 AM

Each time the worm turns around, the output gear advances 1 tooth. So if your reduction is 1:10, the output gear has 10 teeth.

If you had an 8 tooth output gear at 1450 rpm input, the output would be 1450/8 =181.25 rpm, which is close to the output if you use the 10 tooth gear at 1800 rpm (1800/10=180 rpm). If output speed does not need to be exact, it might be an easier option than changing the input speed.

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#3
In reply to #2

Re: Worm Reduction Gearbox

03/10/2016 6:49 AM

Let me restructure the question again

Motor rpm 1450

Motor is driving the gearbox through V-pulley 8 inch

Gear Box input V-Pulley 8 inch

Gear Box ratio 1:10

Gear Box output 38 teeth sprocket

Driven shaft 75 Teeth sprocket

Now I need marginally an increase in output. I have already exercised the option at Gearbox output by increasing the sprocket size.

Can I increase the input rpm of Gearbox from 1450 to say 1800?

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#4
In reply to #3

Re: Worm Reduction Gearbox

03/10/2016 7:14 AM

Yes you can. Most any standard worm gear reduction system is pretty for giving to moderate input speed changes.

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#5
In reply to #3

Re: Worm Reduction Gearbox

03/10/2016 7:45 AM

Changing the ratio of the pulleys make more sense to me than messing about with the gearbox.

Unless there's something else you haven't told us.

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#8
In reply to #3

Re: Worm Reduction Gearbox

03/10/2016 3:01 PM

Sprocket at out put 42 teeth the other one 67 it would be the simplest solution without changing the tribological conditions in the box which could affect its life expectancy.

To verify 1450*(75/38)*(42/67)=1794 error 0.33%

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#6
In reply to #2

Re: Worm Reduction Gearbox

03/10/2016 7:48 AM

It seems to me that the drive and worm are matched by their radii, they are a cut open nut and a bolt topologically so you can not easily change the number of teeth on the worm part without changing the disk.

Thus an increase/decrease in the motor speed is the method. As long as there is proper lubrication the increase in speed should be OK, Bear in mind the lubrication must be applied in a recurring way to the slow wheel as it is driven by the fast worm because dry interaction will soon lead to wear.

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#7

Re: Worm Reduction Gearbox

03/10/2016 12:52 PM

It depends on whether the input torque and horsepower to the gearbox remain sufficient to match the increased output.

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#9

Re: Worm Reduction Gearbox

03/10/2016 8:31 PM

Worm gear speed reducers are selected on the basis of gear ratio, speed, torque (or horsepower) and mounting requirements. Every gearbox has an input rating that it can receive in regards to both RPM and torque. They are generally designed around common Motor RPMs, such as 1750. If your unit in-question is rated at 1750 RPM... there is likely a Safety Factor that could absorb an additional 50 RPM - But your service factor will be impacted. Best to call the GB OEM to verify what the Service Factor impact will be (likely a reduced life-cycle) and if that impact is acceptable to you.

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#10

Re: Worm Reduction Gearbox

03/10/2016 11:37 PM

Put a 10 inch pulley on the motor. You currently have a 1:1 ratio giving a gearbox input speed of 1440. A 1.25:1 ratio will give an input speed of 1800.

Jim

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#11

Re: Worm Reduction Gearbox

03/11/2016 4:52 AM

Dear Mr. gvsrish,

We should NOT blindly decide to increase the ultimate output RPM .

The following are to be checked.

1. Service Factor of Gear Box..

2. Power demand due to increased speed should match with the capacity of the gear box.

3. Impact of the shaft and gear teeth on account of increased speed.

4. Cooling capability of the gear box.

5. Speed limits given by the Gear Box Manufacturer.

Pl.consult the equipment anufacturer.

DHAYANANDHAN.S

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#12

Re: Worm Reduction Gearbox

03/12/2016 2:18 AM

Dear All Gurus,

Thanks for all the valuable inputs. I am also looking for an economical solution. I look at swapping the pulleys could solve without additional investment. My only concern is whether the worm shaft is capable of taking higher input rpm!

The Driven shaft is rotating a pipe and hence has no jerk nor heavy starting torque necessary. Changing the 75 teeth sprocket could be a probable solution but these sprockets are quite expensive.

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Guru

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#13
In reply to #12

Re: Worm Reduction Gearbox

03/12/2016 2:25 AM

The advantage of the suggested solution is that the change occurs AFTER the gear box thus does NOT modify working conditions for it.

May be you look if you can replace sprockets by multi-V belts or other types which are a lot LESS expensive. It depends on the torque you should transmit.

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#14

Re: Worm Reduction Gearbox

03/30/2016 10:00 AM

You likely can increase the input speed, check with the manufacturer. One drawback is that you will likely not have any warranty on the unit.

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