# Advice 1: How to determine gear ratio

One of the devices most commonly used today in a variety of mechanisms, is the gearbox. It is a development of the idea of the lever and serves to transmit torque between the rotating pulleys. The main parameter characterizing a specific gear, is the gear number. It can be defined by performing calculations based on information about the type and parameters of the speed reducer.
You will need
• - knowledge of the parameters of the gear reducer.
Instruction
1
Determine gear ratio, consisting of a single gear. In devices of this type the torque is transmitted from the drive shaft driven by engagement of teeth of the gear installed on them. Gear can be both cylindrical and conical - in this case, it doesn't matter. First determine the number of teeth of the gear drive shaft by a simple calculation. Then perform the same operation for the driven gear shaft. Divide the second value to the first. This will be the desired gear reduction ratio.
2
When calculating gear ratios, made on the basis of chain transmission, operate similarly to the first step. Count the number of teeth of the driving and driven sprockets, and then divide the second value to the first.
3
To estimate the gear ratios on a belt it is necessary to know the radii (or diameters) of its driving and driven pulleys. Please note that this must be the radii of the circles, through which passes the inner part of the belt during its contact with the pulleys. Therefore, if the pulley is made in the form of a roller with a groove to hold a belt, it is necessary to measure the radius or the diameter of its inner part. In this case, to calculate gear ratio by dividing the radius of the driven pulley on the radius host.
4
In gearboxes is based on worm gear leading pulley is always the one on which is located the worm, and the slave - where is the worm wheel. In one revolution of the worm wheel (gear) turns on the number of teeth equal to the number of threads of worm (in the simplest case is a unit). Therefore, the gear ratio of such a gear is calculated by simple division of the number of teeth of the worm wheel by the number of visits worm.
5
The gear ratio of the reducer is composed of gear, determine by successively multiplying the ratios of its individual steps.

# Advice 2 : How to find out gear ratio

The transfer number is one of the main characteristics of any gear mechanism for torque transmission. The transmission number is greater than one in the step-down gearx and less than one in boost, called multipliers.
You will need
• calculator;
• - locksmith set of keys;
• roulette;
• - tachometer.
Instruction
1
The type of transfer gears are classified as follows: cylindrical, conical, worm, planetary and combined. Transmission gear distinguish gear, hypoid gear, chain, belt, screw, wave transmission and friction. For any type of gear gear ratio number is equal to the ratio of frequencies of rotation (or angular velocity) drive shaft and slave.
2
For timing, belt, chain and worm gears gear ratio number can be determined by the type of the elements of the reducer.Open the lid of the gearbox in order to have access to its elements.
3
Gear peridotite the number of teeth of driven gear N and the number Q of the teeth of the driving gear. Divide N by Q. the resulting value ratio (in number) of the reducer gear.
4
Belt paratacamite diameters of the driving and driven pulley. The ratio of larger diameter (leading) to the smaller (slave) — transfer number of a reducer with a belt drive.
5
Chain peridotite the number of teeth of a leading (large) and idler (small) sprocket. Transfer number of a reducer with chain transmission is equal to the ratio of the number of teeth of large and small stars.
6
The worm will predicatability the number of visits to J on the worm and the number of teeth on the worm wheel. The ratio of G to J — transfer number of a reducer , worm gear.
7
The transfer number can be calculated by the speed of rotation of the driving and driven shaft. Measure using a tachometer rotational speed N of the drive shaft, which is driven by a power unit (motor). It is equal to the frequency of rotation of the motor shaft.
8
Measure the number of revolutions n of the driven shaft, which results in the movement of the working body.
9
Divide the frequency of rotation of drive shaft N for the rotational speed of the slave shaft n. The obtained number is the gear ratio of this gear.
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