The construction of construction machinery parts is mainly classified according to functional systems into structural components and transmission/actuation components. The core design principle is a combination of a load-bearing framework, articulated hydraulic drive systems, and modular connections. Although the construction of parts varies significantly among different types of equipment, such as excavators, loaders, and cranes, they generally follow the same engineering logic:
Structural Components
Examples include booms, arms, track frames, and chassis frames. These parts are typically manufactured as welded frame structures or box-section beams made from high-strength low-alloy steel (e.g., Q345/16Mn). The design emphasizes bending and torsional rigidity as well as fatigue resistance. Critical areas are often reinforced with stiffeners or cast-steel strengthening sections. Components are assembled through pin joints or bolted connections, allowing articulation or easy disassembly.
Working Device Components
Examples include buckets, bucket teeth, hydraulic cylinders, and breaker chisels. Buckets are fabricated from wear-resistant steel plates and equipped with replaceable bucket teeth, which can be quickly changed using bolts or locking pins. Hydraulic cylinders consist of a cylinder barrel, a piston rod (induction-hardened and chrome-plated), sealing systems, and cushioning mechanisms, and they transmit force through pivot points and linkage systems. Wear parts such as bucket teeth and tooth adapters are commonly manufactured from high-chromium cast iron or composite wear-resistant materials and are designed for modular, quick replacement.
Traveling and Slewing Components
Examples include track assemblies, track rollers, and slewing bearings. Track assemblies consist of modular track links connected by pins and bushings, with track shoes attached to the links. Track rollers and carrier rollers are typically constructed with heat-treated steel wheel bodies, rolling or sliding bearings, and double-seal systems. Slewing bearings are generally large-diameter single-row or double-row ball or roller turntable bearings with integrated gear rings on the inner or outer race. They are mounted between the upper and lower structures using high-strength bolts.
Connection and Transmission Components
Examples include quick couplers, linkage rods, and reduction gearboxes. These components commonly use pin-and-lug articulations or flange-bolted connections, with particular attention paid to clearance control and anti-loosening measures. Hydraulic piping systems typically consist of high-pressure hoses and cone-seal fittings, while electrical control components include sensor brackets and protective wiring harness sleeves.
