worm and worm wheel


worm– thread is cutted on a cylindrical body. there are a lots of application of worm and worm wheel.

Worm wheel– normal spur gear but when it is connected to a worm then the gear is known as worm wheel.

worm and worm wheel animation
worm and worm wheel


  • Elevators/Lifts
  • Gates and conveyor belts
  • For the turning purpose (Differential)
  • To transfer force or motion or force between two perpendicular shafts
  • Used where large speed reduction is required in small space
  • Also used in musical instrument
  • Automatic steering system


Hello friends here in this blog we will see construction in working of Worm and Worm wheel with the velocity ratio formula now here I have a diagram.

velocity ratio of worm and worm wheel

worm in worm wheel it is also a kind of simple machine where we are lifting a heavy load by applying comparatively less effort.and there are a lots of application of worm and worm wheel. so this is the diagram here I will explain the construction part worm in worm wheel consist of a screw thread which is called as worm it is like a screw and then it is in mesh or in connection with a wheel which is called as worm wheel this worm wheel it looks like a gear now over this warm wheel we are having a load drum or we can say shaft to which the load is attached which we want to lift. r is the radius of the low drum next this worm is connected to the effort wheel which has a bigger diameter and at effort wheel we would be applying the effort now at the same and they have given one more diagram that instead of effort wheel we can even have the handle that is instead of having the wheel we would be having the handle now this was regarding the construction part now how it functions effort would be applied in the downward direction either we can pull this string down when the effort is applied effort wheel starts rotating when effort will rotates it will be rotating the worm and when the worm rotates it is in mesh with the worm wheel this worm wheel will be rotating and when the worm wheel rotates along with it the load drum would be rotating and the string would be wound up onto the load drum and hence the load is lifted so here as we see the input is the effort which we are applying output is the load which gets lifted and here is the velocity ratio formula for moment worm wheel it is given by R into T upon r where R it is the radius of effort V. T it is the number of teeth on the worm or you can say worm wheel number of teeth on worm wheel r it is the radius of load term now this is the effort wheel if we are having effort wheel then we are taking R suppose if we are replacing effort wheel with the help of a handle whose length is L so the formula is L into T by R where L is the length of handle capital T is the number of teeth on one wheel and small r is the radius of load term so I hope in this video you will might have understood worm and worm wheel in detail.

If you want to know about gear and their types click here.



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