# Idler gear torque relationship

### Gear train - Wikipedia

Gears are used to change the torque, speed, and direction of rotation. The driving gear has 30 teeth, the idler gear has 90 teeth and the driven gear has 15 . I can understand each gear delivering the same torque because I can . So the proper balance equation is the force balance equation: FA = FB, . the other gears would become simple idlers because they would be "loose". Gear Ratio expresses the relationship between a Driving Gear (the gear that is LARGER than the Driven Gear you will increase Speed and decrease Torque: Gear and the Driven Gear that only transmit power are known as Idler Gears.

Does half of gear C's torque apply to H1 and half to gear E? And would M1 apply a force to M2 and vice versa? If M1 does not affect H2 and M2 does not affect H1, then what about if these gears are added: I think I'm having trouble tracing where forces are acting.

## Gear Torque Basics

It seems to me that the arrangement of the gears would be important in these cases, but I could be wrong. The important relationship to understand with gears is that at the contact point between 2 gears the forces acting on the tooth of each gear are the same and the linear velocities of each tooth are also the same. From there, you can find torque and angular velocity for each gear.

The problem with the gear set presented above is that they contain redundant gears, meaning that power transmission can take one path or another. When there is symmetry, you can divide the force equally between the paths.

- Gear train

For example, in this case: The other one is only there to "pull" on the first one such that it doesn't fall. But if there was a shaft welded to cylinder block, the second gear would be unnecessary. In real life, in such system, the power can be transmitted through one path only due to manufacturing tolerances; the other gears would become simple idlers because they would be "loose".

For this reason it is called an idler gear. The same gear ratio is obtained for a sequence of idler gears and hence an idler gear is used to provide the same direction to rotate the driver and driven gear. If the driver gear moves in the clockwise direction, then the driven gear also moves in the clockwise direction with the help of the idler gear. The somewhat larger gear in the middle is called an idler gear.

It is not connected directly to either the motor or the output shaft and only transmits power between the input and output gears. There is a third gear in the upper-right corner of the photo. Assuming that gear is connected to the machine's output shaft, it is the output or driven gear.

### 4 Easy Ways to Determine Gear Ratio (with Pictures)

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.

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.