What the difference between a driving gear and a driven gear
A gear train is a mechanical system formed by mounting gears on a frame so the teeth of the The speed ratios of chain and belt drives are computed in the same way as gear ratios. See bicycle . The "input gear" (also known as drive gear) transmits power to the "output gear" (also known as driven gear). The input gear. Gear Ratio expresses the relationship between a Driving Gear (the gear connected to the input power source, such as a motor) and a Driven Gear (the gear. This difference is proportional to the ratio between the lengths of the levers. Thus The Gear Reduction is calculated as Driven Gear Teeth / Driving Gear Teeth.
Assuming that gear is connected to the machine's output shaft, it is the output or driven gear. The input gear in this gear train has 13 teeth and the idler gear has 21 teeth.
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.
At this ratio, it means the drive gear must make 1. Essentially, the larger gear turns slower. The third gear in the picture has 42 teeth.
Gear train - Wikipedia
The idler gear serves to make both the drive gear and the driven gear rotate in the same direction, but confers no mechanical advantage. Belt drives[ edit ] Belts can have teeth in them also and be coupled to gear-like pulleys.
Special gears called sprockets can be coupled together with chains, as on bicycles and some motorcycles. Again, exact accounting of teeth and revolutions can be applied with these machines. Valve timing gears on a Ford Taunus V4 engine — the small gear is on the crankshaftthe larger gear is on the camshaft.
The crankshaft gear has 34 teeth, the camshaft gear has 68 teeth and runs at half the crankshaft RPM. The small gear in the lower left is on the balance shaft. For example, a belt with teeth, called the timing beltis used in some internal combustion engines to synchronize the movement of the camshaft with that of the crankshaftso that the valves open and close at the top of each cylinder at exactly the right time relative to the movement of each piston.
This equates to 4, RPM when used with the Note that due to the nature of the way the gears mesh, they will turn in opposite directions. Most applications are limited in space, and the more teeth you require the greater the diameter of the gear.
Adding in Gears Your first instinct may be to simply add a third gear, but as we will see that this has no effect on the output speed. Remember when two gears are in mesh: However, the addition of the second gear does ensure the input and output gears turn in the same direction. An Intermediary Gear Will Change the Direction of Rotation, but has no Effect on the Speed Compound Gears This is overcome by using what is known as a compound gear, where a single gear has two different sets of teeth: Using a compound gear, lets look at how our speed and teeth relationship is changed.
To explain, we will treat the compound gear as two separate gears B and C that are forced to the same speed. We now have two separate meshes: You can think of the output speed as the input speed times the product of transmitting teeth divided by the product of receiving teeth: