gear ratio Definition and Topics - 14 Discussions

A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the gears engage.
Gear teeth are designed to ensure the pitch circles of engaging gears roll on each other without slipping, providing a smooth transmission of rotation from one gear to the next. Features of gears and gear trains include:

The ratio of the pitch circles of mating gears defines the speed ratio and the mechanical advantage of the gear set.
A planetary gear train provides high gear reduction in a compact package.
It is possible to design gear teeth for gears that are non-circular, yet still transmit torque smoothly.
The speed ratios of chain and belt drives are computed in the same way as gear ratios. See bicycle gearing.
The transmission of rotation between contacting toothed wheels can be traced back to the Antikythera mechanism of Greece and the south-pointing chariot of China. Illustrations by the Renaissance scientist Georgius Agricola show gear trains with cylindrical teeth. The implementation of the involute tooth yielded a standard gear design that provides a constant speed ratio.

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  1. E

    How do I select the right motor and gear ratio for a mid-drive e-Bike?

    Hey all! I am working on my first ebike build and posted a question about friction drives earlier. Now, I have decided to go with a Mid-drive. I made calculations and found out the torque and rpm required for the build. But I am having difficulty find the right motor and gear ratio. I am trying...
  2. Z

    Calculating gear ratio from the motor's graph for an EV?

    Dear community, For my electric vehicle project I want to select a gear ratio (single) of my gear box and send this information to the supplier. In order to calculate this ratio I thought of the following steps but am not sure and want some expert to recheck and answer my queries: 1. Calculate...
  3. K

    Help with torque and power required please

    I am looking to build a skateborad like device that i want to power with electric skateboard-like system. However I only want it to go 1.1m/s using 60mm wheels moving a 100kg load for 12 km. I am looking for help determining gear sizes, motor sizes and specs, really anything. I have seen so...
  4. J

    How to increase output speed

    For a project I am doing I need to increase out put speed to 515 rpm from 1rpm with no more than a 20% decrease in torque, I need help I have been trying a lot of things and can't figure it out.
  5. Gurfin321

    Automotive Electric Longboard Gear Ratio

    I would like to know what gear ratio i would need for my electric longboard. The goal is to run the longboard at 30 - 40 km/h at max power. Me and the longboards weight is approximately 65 kg. The brushless motor i am running has an rpm of approximately 18000 rpm (as it is an airplane engine)...
  6. B

    SolidWorks worm reducer analysis tutorial needed

    I've calculated my gear ratio to be 1:27 and the most suitable reducer for it would be a worm drive. I couldn't find any descriptive tutorials to do the mesh and perform constructional analysis of the gears on SolidWorks. Can you help me?
  7. E

    Gear ratios example question

    Hi, I don't get the right answer for this question. I don't see where I'm going wrong. I use this equation to get the engine rpm for each gear ratio: engine speed (rpm) = gear ratio X final drive ratio X vehicle speed X 60 / (2*pi*rolling radius) So for first gear I get an engine rpm of...
  8. T

    Optimization of windmill power with use of gears

    < Mentor Note -- thread moved to HH from the technical Engineering forums, so no HH Template is shown > Okay so I'm a freshman BE student and one of our first projects is designing a windmill that can produce a voltage of 5 for 2 seconds or longer. We are having trouble find the optimal gear...
  9. J

    Gear Ratios and Constant Power/Torque: find max velocity?

    I'm trying to determine how exactly gear ratio limits velocity. I know that a high torque configuration is generally regarded as low speed, but my calculations do not seem to support that. Basically, I've written a small problem where we have an input gear with constant torque and an output...
  10. F.Turner

    Reverted Gear train

    < Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > I have a design problem that has two predictions that I must make. The constants that I am given is the amount of teeth each gear has, the diameter of the gears, the input torque, speed in...
  11. Karan Dua

    Transmission System

    Hey guys, I am a bit confused while calculating top speed of the car using gear ratio, Torque, Power and Engine Speed(RPM). Can someone help me out with this? Specifications are given as follows: Maximum Torque : 19.2 N-m @ 3800 RPM Maximum Power : 10 Hp @ 2800 RPM Tire Specifications: 25x8...
  12. A

    Worm gear calculation

    Dear all, I am trying to build single axis solar tracker using worm gear, I need guide line for calculation of worm gear & stepper motor .he are some relation i taken, But i wanted whether its correct & need to explain with example efficiency= (output Power of Worm gear/ Input Power of...
  13. CJNight15

    Motor that can move possibly up to 4kg

    I'm designing a robot to compete against a friend who is also making a robot based on the Robot Sumo competitions. We decided on the dimensions of our bots and placed a 2kg limit on their weight. I'm having trouble determining what motor to use that will be able to move my own ~2kg robot around...
  14. Z

    What gears to use to reduce fan speed from fast moving motor

    hey, I am building a fan, but I need the fan blade to move relatively slow, slow enough to see each panel on the blade. I am expecting to use a gear system with a belt. What gears should I use to active this?