Talking about the four wheels in“Four wheels and one belt”

Basic introduction
The four wheels in “four wheels and one belt” refer to the drive wheels, guide wheels, roller and carrier wheels, and the belt refers to the crawler belt. They are directly related to the working performance and walking performance of excavators, and their weight and manufacturing cost account for a quarter of the manufacturing cost of excavators.
The four wheels in “four wheels and one belt” refer to the drive wheels, guide wheels, roller and carrier wheels, and the belt refers to the crawler belt.They are directly related to the working performance and walking performance of excavators, and their weight and manufacturing cost account for a quarter of the manufacturing cost of excavators.

crawler
Classification: there are two types: integral type and combined type. The integral crawler is a track shoe with meshing teeth, which tends to mesh with the drive wheels. The track shoe itself becomes the rolling track of wheels such as roller wheels. Features: easy to manufacture, but fast wear. At present, excavators are mostly used in combination, which is characterized by small pitch, good revolving performance and fast walking speed. Long service life.
The materials used for the track shoes are mostly rolled plates with light weight, high strength, simple structure and low price. There are single reinforcement, double reinforcement and three reinforcement. Most excavators now use three bars. It is characterized by small height of rib and high strength of track shoe. Smooth movement and low noise.
There are generally four connecting holes on the track shoe, and two mud cleaning holes in the middle, which are used to automatically remove clay. There are overlapping parts between two adjacent track shoes to prevent damage caused by stones.Excavators on wetlands can use triangular track shoes with triangular cross-section, which can compress the soft ground and improve the support capacity.

Sprocket
The power of the engine of the hydraulic excavator is transmitted to the crawler through the traveling motor and the drive wheel. It is required that the drive wheel and the track chain of the crawler mesh correctly, drive smoothly, and still mesh well when the track is extended due to wear of the pin sleeve.
The drive wheel is usually located at the rear of the excavator traveling device.
According to the structure, it can be divided into: integral type and split type
According to the pitch, it can be divided into: equal pitch, unequal pitch
Material: 50Mn, 45simn, and its hardness reaches hrc55-58

Track Roller
The function of the roller is to transmit the weight of the excavator to the ground. When the excavator runs on the uneven road, the roller will suffer from the impact force of the ground. Therefore, the roller bears a large load and has poor working conditions. It is often in the dust and sometimes soaked in mud. Therefore, it is required to have a good seal.
Materials: 35MN and 50Mn are mostly used. The wheel surface is quenched and the hardness reaches hrc48 and 57 to obtain good wear resistance.
Features: mostly supported by sliding bearings. And use floating oil seal to prevent dust. Generally, it is only necessary to add grease once in an overhaul period, which simplifies the usual maintenance of the excavator.

Idler
The guide wheel is used to guide the track to rotate correctly and prevent it from running off the track. Most excavators also function as roller. In this way, the contact area between the crawler and the ground can be increased and the ground specific pressure can be reduced. The wheel surface of the guide wheel is made into a smooth surface, with a retaining arm ring in the middle as a guide, and the ring surfaces on both sides support the rail chain.
The smaller the distance between the guide wheel and the nearest supporting wheel, the better the guidance. Material: 40, 50 steel, or 35MN, cast, Quenched and tempered, hardness hb230-270
Key points: in order to make the guide wheel play its role and prolong its service life, the radial runout of the wheel face to the central hole should be less than or equal to 3mm, and it should be correctly aligned during installation.

Carrier Roller
Its function is to support the crawler upward and make the shoes have certain tension.