Common excavator structures include power units, working devices, slewing mechanisms, control mechanisms, transmission mechanisms, walking mechanisms, and auxiliary facilities.
The transmission mechanism transmits the power of the engine to the hydraulic motor, hydraulic cylinder and other actuating components through a hydraulic pump, pushing the working device to move and complete various operations.
Walking device
The walking device, also known as the chassis, includes a track frame and a walking system. It mainly consists of a track frame, a walking motor+reducer and its pipelines, driving wheels, guide wheels, idler wheels, support wheels, tracks, and tension buffer devices. Its function is to support the weight of the excavator and convert the power transmitted by the driving wheels into traction force, achieving the walking of the whole machine.
The frame assembly (i.e. track walking frame assembly) is an integral welded component with an X-shaped structure, which has the main advantage of high load-bearing capacity. The frame assembly is welded together from three parts: the left longitudinal beam (i.e. left track frame), the main frame (i.e. middle frame), and the right longitudinal beam (i.e. right track frame). The weight of the frame assembly is 2 tons.
The central rotary joint is a hydraulic component that connects the rotary platform and the chassis oil circuit. It ensures that the walking motor can still supply oil normally after the rotary platform rotates at any angle. The current rotary joint is 5-way.
Working device
The working device is the main component of hydraulic excavators. Currently, the SY series excavators are equipped with a backhoe working device, which is mainly used to excavate soil below the stopping surface, but can also excavate soil below the maximum cutting height. In addition to digging pits, digging trenches, and loading, it can also perform simple leveling work on the site. Excavation operations are suitable for excavating soil of grades I-IV, with hydraulic hammers or blasting methods required for grades V and above.
The backhoe working device consists of the boom, arm, bucket, rocker, connecting rod, and hydraulic pipelines including the boom cylinder, arm cylinder, and bucket cylinder.
Power transmission route table
1. Power transmission route for walking: diesel engine - coupling - hydraulic pump (converting mechanical energy into hydraulic energy) - distribution valve - central rotary joint - walking motor (converting hydraulic energy into mechanical energy) - gearbox - driving wheel - rail chain track - realizing walking
2. Transmission route of rotary motion: diesel engine - coupling - hydraulic pump (converting mechanical energy into hydraulic energy) - distribution valve - rotary motor (converting hydraulic energy into mechanical energy) - gearbox - rotary bearing - realizing rotary motion
3. Transmission route for boom motion: diesel engine - coupling - hydraulic pump (converting mechanical energy into hydraulic energy) - distribution valve - boom cylinder (converting hydraulic energy into mechanical energy) - realizing boom motion
4. Transmission route of stick motion: diesel engine - coupling - hydraulic pump (converting mechanical energy into hydraulic energy) - distribution valve - stick cylinder (converting hydraulic energy into mechanical energy) - realizing stick motion
5. Transmission route for bucket movement: diesel engine - coupling - hydraulic pump (converting mechanical energy into hydraulic energy) - distribution valve - bucket cylinder (converting hydraulic energy into mechanical energy) - realizing bucket movement
Composition and function of power system
- Air intake system - mesh cover → rubber hose → air filter → rubber hose → supercharger → rubber hose → intercooler → rubber hose → engine
- Exhaust system - turbocharger → expansion joint → muffler → exhaust pipe
- Cooling System - Water Tank → Rubber Hose → Thermostat → Water Pump → Diesel Engine → Rubber Hose → Water Tank
- Throttle control system - stepper motor → reducer → worm gear transmission → throttle cable → diesel engine throttle - high idle, low idle limit switch
- Fuel system--
- Oil inlet system: fuel tank → hose → manual oil pump → coarse filter → fine filter → diesel engine
- Return oil system: diesel engine → hose → fuel tank (with a relatively large return oil volume, it is used for partial cooling)
