Gear Train Calculations Pdf

The speed ratio for a pair of meshing gears can be computed from ratio of the radii of the pitch circles and the ratio of the number of teeth on each gear. This shows that if the input gear rotates faster than the output gear, then the gear train amplifies the input torque. By compounding, a much smaller set of gears can be used to achieve a large number of ratios.

This article needs additional citations for verification. Pool pump troubleshooting Solved! The pitch of a gear G A can be computed from the number of teeth N A and the radius r A of its pitch circle. Neither, one, or the other.

Planetary gear ratio calculations

Again, exact accounting of teeth and revolutions can be applied with these machines. This is because the close-ratio transmission has less of a progression between gears. In such an example, the output of torque and rotational speed from the output driven gear depend on the ratio of the dimensions of the two gears.

The somewhat larger gear in the middle is called an idler gear. If we assume the gears are rigid and there are no losses in the engagement of the gear teeth, renault megane 3 service manual pdf then the principle of virtual work can be used to analyze the static equilibrium of the gear train. You can continue this process along a train of many gears to find a ratio for the whole train.

For this analysis, we consider a gear train that has one degree-of-freedom, which means the angular rotation of all the gears in the gear train are defined by the angle of the input gear. If the output gear of a gear train rotates more slowly than the input gear, then the gear train is called a speed reducer.

Illustrations by the Renaissance scientist Georgius Agricola show gear trains with cylindrical teeth. Two meshing gears transmit rotational motion. In the photo, assuming the smallest gear is connected to the motor, it is called the drive gear or input gear.

If the elevator is loaded to half capacity, the motor lifts no weight but then just accelerates the mass. In other words, the gear ratio, or speed ratio, is inversely proportional to the radius of the pitch circle and the number of teeth of the input gear. Prudens, I don't mean to brush you off, but have you looked at howstuffworks. Please help improve this article by adding citations to reliable sources.

Planetary gear ratio calculations

There is a third gear in the upper-right corner of the photo. The intermediate gear provides spacing but does not affect the gear ratio.

The total reduction is the product of the first stage of reduction and the second stage of reduction. Engineering Mechanical Engineering. Not only do larger gears occupy more space, the mass and rotational inertia moment of inertia of a gear is proportional to the square of its radius.

It was easy to calculate the resulting gear ratio when we knew which gears were involved but here we have the opposite problem. If the car had smaller tires, it would be like a lower gear. Instead of idler gears, a toothed belt or chain can be used to transmit torque over distance.

How do you calculate Gear Train Radios? Home contributions Gear Ratio Calculations. Articles that may contain original research from April All articles that may contain original research Articles needing additional references from April All articles needing additional references.

Gear teeth are distributed along the circumference of the pitch circle so the thickness t of each tooth and the space between neighboring teeth are the same. However, the addition of each intermediate gear reverses the direction of rotation of the final gear. 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.

Gear Ratio Calculations

If the Corvette had larger tires, it would travel farther with each revolution of the wheel, which would be like a higher gear. It is also possible to determine a car's speed from the engine speed by multiplying the circumference of the tire by the engine speed and dividing by the combined gear ratio.

The idler gear serves to make both the drive gear and the driven gear rotate in the same direction, but confers no mechanical advantage. Here is where it gets backwards with lay terminology, low gear like first gear has a high ratio and high gear overdrive has a low ratio. Normally, the gear setups for common thread pitches are covered in the documentation that comes with the lathe. Considering only these gears, the gear ratio between the idler and the input gear can be calculated as if the idler gear was the output gear. Belts can have teeth in them also and be coupled to gear-like pulleys.

Gear Train Ratio Calculation

Think of you and a row of friends in a movie theater. In simple gearing, as we saw, the ratio depends only on the driver and driven gear - any gears between these can't affect the overall ratio. This section possibly contains original research.