The four-wheel belt in the chassis parts of the excavator of Guangzhou Guoli Construction Machinery Co., Ltd. refers to: roller wheel, drive wheel, guide wheel and carrier roller. A belt refers to a track. The rollers, as the name suggests, play a supporting role and are located between the lower surface of the left / right beam of the chassis frame and the tracks. Guangzhou Guoli construction machinery according to the tonnage of the excavator is different, usually 5-10 on one side. The drive wheel plays the role of driving the track, fixed on the travel motor, and transmits the drive of the travel motor to the track through the gear structure, usually one on each travel motor. The idler acts as a guide track and is located opposite the drive wheel, usually two per excavator. The carrier roller plays the role of supporting the track, and according to the size of the excavator tonnage, there are usually 1-2 carrier sprockets on one side.