Why do construction machinery often use hydraulic drive?

Hydraulic drive has the following advantages:
High power density: Hydraulic systems can transmit large power or torque in a small volume (motor or oil cylinder), which is often referred to as a high power density ratio. Therefore, using hydraulic drive in machinery can achieve high efficiency.

Good flexibility: The hydraulic system can perform long-distance transmission, and its output force, speed, and position parameters can be quickly and accurately controlled manually or automatically. Hydraulic transmission also has the characteristic of infinite speed regulation.

High reliability: Mechanical components are effectively reduced in terms of friction, impact, and wear due to the presence of hydraulic oil.

Good economy: Compared to electric motor drive, the design cost of hydraulic system is lower and maintenance is relatively simple at the same horsepower.

Because hydraulic power transmission has a higher density