riduttore 9 braccia


The gearbox is the main mechanical component of the kinematic chain of agricultural machines. It is normally driven by the tractor power take-off via the PTO shaft and the gearbox drives. The operating torque can also be transmitted to the gearbox by hydraulic motors or belt pulleys, in addition to chain gears.

Gearboxes always have one input shaft and at least one output shaft. If these shafts are positioned at 90° to each other, the gearbox is an ORTHOGONAL ANGLE gearbox or more commonly called a right-angle gearbox.

If the input and output shafts are placed parallel to each other, the gearbox is known as PARALLEL SHAFT gearbox.

Based on the gears and the number of teeth, the CMR Group range of gearboxes includes:

Increasers and Reducers

When the gearboxes have the two gears with different numbers of teeth.

The gearbox is a reducer when the driving gear, i.e. the one with the input shaft, has the fewer number of teeth (pinion), thus the output shaft rotates slower than the input shaft.

It is called an increaser when the input shaft is mounted on the gear with the larger number of teeth (crown), thus the output shaft rotates faster than the input shaft.

Right-angle gearboxes, distributors or rotational reverse gearboxes

When the gearboxes have gears with the same number of teeth.

The gearbox is known as right-angle when it only has two shafts (input and output),

whereas it is called a distributor when there are at least two output shafts.

It is called a rotational reverse gearbox and parallel offset in the versions with parallel shafts with two gearboxes.

Speed change

in addition to the main pair of gears and relevant shafts, the gearboxes may also have other gears with a different number of teeth. The gear shift of the main pair of gears with the secondary ones allows different speeds. The manual switch of the secondary gear pair with gears with different number of teeth allows modifications to the output rotation speed.

CMR GROUP is able to design and manufacture also agricultural machinery applications.