Common excavator structures include power plant, working device, rotary mechanism, control mechanism, transmission mechanism, walking mechanism and auxiliary facilities.

The transmission mechanism transmits the power of the engine to the hydraulic motor, hydraulic cylinder and other executive components through the hydraulic pump to promote the action of the working device, so as to complete various operations.

Walking device

The walking device is the chassis, including the track frame and the walking system, which is mainly composed of the track frame, the walking motor + reducer and its pipeline, the driving wheel, the guide wheel, the sprocket wheel, the weight support wheel, the track, and the tension buffer device. Its function is to support the weight of the excavator, and convert the power transmitted by the driving wheel into traction force to realize the walking of the whole machine.

The frame assembly (that is, the track walking frame assembly) is an integral welding part, using an X-shaped structure, and its main advantage is that it has a high carrying capacity. The frame assembly is welded in three parts: the left longitudinal beam (that is, the left track frame), the main frame (that is, the middle frame), and the right longitudinal beam (that is, the right track frame). The weight of the frame assembly is 2 tons.

The central rotary joint is a hydraulic component connecting the rotary platform and the chassis oil circuit, which ensures that the traveling motor can normally distribute oil after the rotary platform is rotated at any Angle. The current rotary joint is 5-way [4].

Working device

The working device is the main part of the hydraulic excavator, the current SY series excavator is configured with a backhoe working device, it is mainly used to dig the soil below the stop surface, but it can also dig the soil below the maximum cutting height, in addition to digging, ditching, loading can also carry out simple site leveling work. The excavation operation is suitable for excavating grade Ⅰ~Ⅳ soil, and above grade Ⅴ, hydraulic hammer or blasting means are required.

The backhoe working device is composed of boom, bucket rod, bucket, rocker rod, connecting rod and hydraulic pipeline of working device including boom cylinder, bucket rod cylinder and bucket cylinder.

Power transmission route table

1. Walking power transmission route: diesel engine - coupling - hydraulic pump (mechanical energy into hydraulic energy) - distribution valve - central rotary joint - walking motor (hydraulic energy into mechanical energy) - reducer box - driving wheel - rail chain track - to achieve walking

2. Rotary transmission route: diesel engine - coupling - hydraulic pump (mechanical energy into hydraulic energy) - distribution valve - rotary motor (hydraulic energy into mechanical energy) - gearbox - rotary support - to achieve rotary

3. Transmission route of boom movement: diesel engine - coupling - hydraulic pump (mechanical energy into hydraulic energy) - distribution valve - boom cylinder (hydraulic energy into mechanical energy) - to achieve boom movement

4. Bucket rod movement transmission route: diesel engine - coupling - hydraulic pump (mechanical energy into hydraulic energy) - distribution valve - bucket rod cylinder (hydraulic energy into mechanical energy) - to achieve bucket rod movement

5. Bucket movement transmission route: diesel engine - coupling - hydraulic pump (mechanical energy into hydraulic energy) - distribution valve - bucket cylinder (hydraulic energy into mechanical energy) - to achieve bucket movement

Structure and function of power system

· Air intake system -- mesh cover → hose → air filter → hose → supercharger → hose → intercooler → hose → engine

· Exhaust system -- supercharger → expansion joint → muffler → exhaust pipe

· Cooling system -- water tank → hose → thermostat → water pump → diesel engine → hose → water tank

· Throttle control system -- stepper motor → reducer → worm gear drive → throttle cable → diesel throttle - high idle speed, low idle speed limit switch

· Fuel system --

Feeding system: fuel tank → hose → hand oil pump → coarse filter → fine filter → diesel engine

Oil return system: diesel engine → hose → fuel tank (the amount of oil return is relatively large, use it for partial cooling)