Excavator, also known as excavating machinery, also known as excavator, is an earth-moving machine that uses a bucket to excavate materials above or below the bearing surface and load it into a transport vehicle or unload it to a stockyard. The materials excavated by the excavator are mainly soil, coal, silt, and pre-loose soil and rocks. From the perspective of the development of construction machinery in recent years, the development of excavators is relatively fast, and excavators have become one of the most important construction machinery in engineering construction. The three most important parameters of an excavator: operating weight (mass), engine power and bucket capacity.
Operating weight is one of the three important parameters of an excavator (engine power, bucket capacity, operating weight)
The operating weight determines the level of the excavator and the upper limit of the excavator's digging force.
Digging force≦m; working weight
m: Adhesion coefficient between the ground and the track
If the digging force exceeds this limit, in the case of a backhoe, the excavator will slip and be pulled forward, which is very dangerous. In the case of a forward shovel, the excavator will slip backward.
For the digging force, the digging force is mainly divided into the forearm digging force and the bucket digging force.
The action point of the two digging forces is the root of the bucket (the lip of the bucket), but the power is different. The digging force of the forearm comes from the forearm cylinder; and the digging force of the bucket comes from the bucket cylinder.
Bucket digging force
Bucket digging force
The specific ground pressure determines the ground conditions that the excavator is suitable for working.
Ground pressure refers to the pressure generated by the weight of the machine on the ground, expressed by the following formula:
Ground pressure = working weight ÷ total area in contact with the ground
·It is very important to install suitable track shoes on the machine. For crawler excavators, the criteria for selecting the crawler is: whenever possible, try to use the narrowest crawler shoe.
Common track types: toothed track shoes,
Flat track shoe
Flat track shoe
For crawler excavators, the walking time accounts for about one-tenth of the entire working time.
Generally speaking, two speeds can meet the walking performance of excavators.
Traction force refers to the force generated when the excavator is walking, and it mainly depends on the walking motor of the excavator.
These two walking performance parameters indicate the maneuverability and walking ability of the excavator. It can be reflected in the samples of various manufacturers.
Climbing ability refers to the ability to climb, descend, or stop on a solid, level slope.
Two representation methods: angle, percentage
Lifting capacity refers to the smaller one of the rated stable lifting capacity or the rated hydraulic lifting capacity.
Rated stable lifting capacity: 75% of tipping load
Rated hydraulic lifting capacity: 87% hydraulic lifting capacity
Rotation speed refers to the average maximum speed that the excavator can achieve in a stable rotation when there is no load.
This means that the defined slewing speed does not refer to the slewing speed when starting or braking; that is, it is not the slewing speed for acceleration or deceleration. For general excavation work, when this kind of excavator works in the range of 0° to 180°, the slewing motor accelerates or decelerates, and when it turns to the range of 270° to 360°, the slewing speed is stable.
Therefore, in actual excavation work, the rotation speed defined above is impractical. In other words, the actual turning performance required is acceleration/deceleration that can be expressed by turning torque.
Gross horsepower refers to the output power measured on the engine flywheel without power consumption accessories, such as silencers, fans, alternators, and air filters.
Effective power (net horsepower) refers to the output power measured on the engine flywheel with all power-consuming accessories such as muffler, fan, alternator and air cleaner.
The main source of excavator noise is the engine.
Two kinds of noise: noise measurement at the ear of the operator, noise measurement around the machine