1 Overview:
The four wheels in “four wheels and one belt” refer to: sprocket, idler, track roller and carrier roller. Belt refers to the track. They are directly related to the working performance and walking performance of the excavator, and its weight and manufacturing cost account for a quarter of the manufacturing cost of the excavator itself.
2.——TRACK GROUP:
The TRACK GROUP is to transmit the gravity of the excavator and the load of working and walking to the ground. Excavators can be divided into steel TRACK GROUP and rubber TRACK GROUP according to the material. The steel TRACK GROUP has good wear resistance, convenient maintenance and good economy, so it is widely used. Rubber TRACK GROUP is generally used on small hydraulic excavators to protect the road from damage.
The track shoes for steel track classification: there are two kinds of integral type and combined type. The integrated TRACK GROUP track shoes has meshing teeth, which tend to mesh with the sprocket, and the track shoe itself becomes the rolling track of wheels such as rollers. Its characteristics are: easy to manufacture, but fast wear.
Now the multi-purpose combination of excavators is characterized by small pitch, good revolving, and fast walking speed of excavators. Long service life, the material of the track shoe is mostly rolled plate which is light in weight, high in strength, simple in construction and cheap in price. Rolled sheets are available in Shuzhong materials such as single-bar, double-bar and triple-bar. Now excavators use three ribs. Its characteristics are that the height of the ribs is small, the strength of the track shoes is large, the movement is smooth, and the noise is small.
There are 4 connecting holes on the track plate, and there are two cleaning holes in the middle, which are used to automatically remove the clay. There are overlapping parts between the two adjacent track shoes, and the two adjacent track shoes are made into overlapping parts. Prevent excessive tension from being sandwiched between the tracks.
The excavator on the wetland can use the triangular TRACK GROUP shoe, and its cross section is triangular, which can be compacted on the soft ground and improve the supporting capacity.
3.——Sprocket:
The power of the hydraulic excavator engine is transmitted to the TRACK GROUP through the traveling motor and the driving wheel. It is required that the driving wheel and the chain rail of the TRACK GROUP are properly meshed, the transmission is smooth, and the TRACK GROUP can still be well meshed when the pin sleeve is worn and stretched. The phenomenon of “jumping teeth”. The sprockets of the track running gear are usually placed at the back. In this way, the length of the tensioning section of the track can be shortened, the power loss can be reduced, and the service life of the track can be improved.
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 and unequal pitch
Material: 50Mn 45SIMN, and make its hardness reach HRC55-58
4.——Idler:
The idler is used to guide the track to run correctly, which can prevent it from deviating and deviating from the track. Most of the hydraulic idlers also play the role of rollers, which can increase the contact area of the track to the ground and reduce the specific pressure. , The wheel surface of the idler is mostly made of smooth surface, and there is a shoulder ring in the middle for guiding. The torus on both sides can support the rail chain and play the role of a roller. The smaller the distance between the closest rollers, the better the idler performance
Material: mostly 40/50 steel or 35MN, cast, quenched and tempered, hardness HB230-270
Advantages: In order for the idler to function and prolong its life, the radial run out of the wheel facing the center hole should be less than or equal to 3MM, and it should be correctly centered during installation.
5. – Track roller:
The function of the rollers is to transmit the weight of the excavator to the ground. When the excavator is driving on uneven roads, the rollers will be impacted by the ground. Therefore, the rollers are subject to large loads and poor working conditions, often in dust. Sometimes it is also soaked in muddy water, so a good seal is required.
Material: Use more than 50mn to create. The wheel surface is quenched, and the hardness reaches HRC48~57 to obtain good wear resistance.
Features: most of them are supported by sliding bearings. And dustproof with floating oil seal.
Generally only need to add butter once during an overhaul period, which simplifies the usual maintenance work of the excavator.
6.—— Carrier roller
The function is to hold the TRACK GROUP up, so that the TRACK GROUP has a certain degree of tension.
Based on the above knowledge, we can roughly understand the basic knowledge of the four-wheeled area, and have a general understanding of the four-wheeled area.
As an excavator, the chassis walking device of the bulldozer accounts for a quarter of the manufacturing cost of the whole machine, which shows its importance.
For some domestic and international excavator brands and codes are as follows:
Domestic: Sany (SY) Liugong (CLG) Yuchai (YC) Xiamen Engineering (XG) Xugong (XE) Longgong (LG) China United (ZE) Sunward Intelligent (SWE)
Japan: Komatsu~(PC) Hitachi~(EX, UH, ZAX) Kobelco~(SK, K) Sumitomo~(SH) Kato~(HD) Kubota~(U, K, KH, KX) Ishikawa Island~ (IS , IHI) Takeuchi ~ (JB)
Korea: Doosan/Daewoo (DH, DX) Hyundai (R)
United States: Caterpillar (CAT) Case (CX)
Sweden: Volvo (VAVO, EC)
Germany: Atlas (ATLS)
and many more………
In Komatsu excavators: PC in excavators stands for TRACK GROUP hydraulic excavators, and D stands for TRACK GROUP bulldozers.
The number behind the PC indicates the working weight of the excavator, which is also the basis for distinguishing the size of the excavator. For example, PC60, PC130, and PC200 represent TRACK GROUP hydraulic excavators of 6T, 13T, and 20T levels, respectively. However, if PC200-2 appears, the last -2 here represents algebra, so we can understand it as the second generation product of Komatsu 200 TRACK GROUP hydraulic excavator with 20 tonnage.
Product knowledge to understand some, then the manufacturing process of the production process should also have a general understanding:
The technical process of the roller includes the following steps:
Wheel body: blanking → forging → car making → heat treatment → oil drilling → electric welding → finishing turning → to be assembled → pressing copper sleeve
Side cover: forging→roughing and finishing turning→milling→drilling mounting hole→chamfering→drilling hole→grinding→to be assembled
Center shaft: blanking→rough turning→heat treatment→milling machine→drilling hole-finishing→to be assembled
After all the above processes are completed, the final assembly process operation is carried out. The specific operations are as follows: three parts cleaning, polishing → assembly → pressure test → refueling → pressure test → grinding → painting → packaging → storage
The technological process of the carrier roller includes the following steps:
Wheel body: blanking → forging → rough turning → drilling oil hole → heat treatment → precision work → pressing copper sleeve → drilling rear cover mounting hole → electric welding → storage
Bracket: blanking→forging→rough and fine turning→milling machine→drilling mounting hole→chamfering→drilling hole
Front cover Rear cover: blanking → roughing and finishing turning → drilling → countersinking → changing teeth → oiling and storage
Support shaft: blanking → rough turning → oil drilling → heat treatment → fine grinding → storage
After all the above processes are completed, the final assembly process operation is carried out. The specific operations are as follows:
Cleaning and polishing → assembling → pressure testing → refueling → grinding → painting → packaging and storage
The process flow of the idler includes the following steps:
Wheel body: blanking → casting → rough and fine turning → milling machine → drilling mounting holes → chamfering → matching → storage
Bracket: blanking → rough turning → heat treatment → milling machine (some do not need milling) → fine grinding → matching
After completing the above two steps, proceed to the final assembly process operation. The specific operations are as follows: polishing→cleaning→wheel body pressing copper sleeve→assembly→pressure test→refueling→grinding→painting→packaging and storage
The technological process of the driving wheel is as follows:
Forging → heat treatment → rough and fine turning → drilling (installation holes) → chamfering → grinding → repairing → painting → packaging and storage
The chain process operation is as follows:
Blanking → double-sided milling → drilling → chamfering → inner square hole milling
Post time: Apr-30-2022
