component in that conversion, it being the part that actually turns the wheels or moves the tracks. However, it often gets overlooked when it comes to care and maintenance, due in part to the fact that many operators who are not mechanics don’ t really know what it is, let alone where.
Where Is It Located?
While some can be standalone components, most are integrated into the axle housing of the machine. For example, they are in the hubs of the drive( rear) sprockets of an excavator, the front wheels of a skip loader and in the sprocket which gives a track loader the“ hump” in its track.
How Does It Work?
The most common final drives are enclosed boxes that contain two, three or more planetary gears that are turned by a much smaller sun gear and held in place by a stationary toothed ring gear. The planetary system gets its name from its analogy to orbiting planets circling around the sun. It is also known as an epicyclic gear system. By the time the power has reached the sun gear, it has already been stepped down considerably and at the same time the torque has exponentially increased. However, this last piece of the drivetrain puzzle gives that powertrain a tremendous amount of work-producing torque. The relatively tiny sun gear spins very rapidly as it turns the much larger planet gears, which in turn rotate the wheels or move the track. The more planet gears, the more driving power is delivered without overtaxing the drivetrain.
Signs of Failure
As with all components of all machines, final drives are subject to failure. What are some of the signs to look for? The most common indicators are heat, noise and leakage. If you throw some water on the exposed part of the final drive and it evaporates immediately, you have a problem with excessive heat. The motor itself may not be bad; it could
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