The ultimate drive motor of an excavator is a hydraulic motor with a planetary gear set that decelerates and multiplies the torque. We will discuss the planetary gear sets and their components as well as their working methods. In the following article we will provide some The ultimate transmission example from reality, and then discuss how to maintain the gearbox.

Low Speed, High Torque Motors.

Most of the hydraulic motors used for propel motors are low-speed, high-torque (LSHT) motors. Speed and torque are related by power:

Power = Speed x Torque

 That means if we want to increase torque for a given horsepower, we need to reduce speed:

Torque = Power / Speed

Hence the term “low-speed, high-torque.”  One way of reducing speed involves the use of planetary gears. They provide speed reduction which results in torque multiplication.  And they do this all in a compact package when compared to gear and pinion speed reducers, and that means they have excellent torque density.  Below you can see a planetary gear system from a final drive motor.

Planetary Gear Systems.

In the gear hub of the final reducer, there are generally two sets of planetary gears that rotate around the sun gear.

  They also mesh with the fixed gear ring. As shown in the figure above, the planetary gear set above is fixed together by a planetary carrier. As shown in the figure, all three gears are divided into equal distances from each other. In the center is where the sun gear meshes and provides input to the system.

How Final Drive Planetary Gears Work.

Let us briefly look at how the planetary gears in the excavator ultimate drive work. The input power causes the sun gear to rotate at high speed. The planetary gear meshes with the sun gear and the ring gear. They revolve around the sun gear as they roll around the ring gear. The result is low speed, high torque output rotation.

Maintaining the Planetary Gearbox.

On the main drive motor, the planetary gearbox needs to be lubricated with gear oil to reduce the friction of the gears. It is very important to check the gear oil level every 100 hours and change the gear oil once a year. If you don’t change out your gear oil,   Will cause the old gear oil to produce thick sludge, which will cause excessive wear of the planetary gear system and reduce the life of the ultimate transmission of the excavator.

 Another key aspect of maintaining planetary gearboxes is to repair all leaking seals immediately. If the seal ring oxidizes or degrades and expands and shrinks to the extent that the oil can leak, it means that dust may enter the gearbox. If you don’t want the gears to look like the hard chaos shown below, please replace the seal oil seal in time.

Conclusion.

The planetary gearbox is a key component of the ultimate transmission. If damaged, you will not be able to produce the torque needed to maintain the machine. Remember to check and replace the gear oil. Don’t ignore leaks. And don’t forget that sludge and grit are not needed in the gearbox.