What is an excavator used for?

1. The work of excavator

An excavator is a working machine used to dig up soil. It uses the teeth of the shovel to cut the soil and put it into the bucket. After filling the bucket with soil, it lifts the shovel bucket and turns back to the unloading point to unload the soil. Then the turntable turns around and the shovel drops down to the digging surface. And then proceed to the next dig. Dig round and unload - to return to a working loop called a excavator.

Excavator is a kind of multi-purpose earth and stone laying machine, the main purpose is to dig and load the earth and stone, and it can also be used for leveling the earth, repairing the slope, lifting, breaking, removing, ditching and other work. So it can be widely used in the construction of roads, railways and other roads, the construction of Bridges and beams, the construction of cities, the port of airports and the construction of water. The excavator also has the function of pushing machine, loading machine, lifting machine, etc., and can replace these mechanical work.

2. The composition of the excavator

The design of excavator is quite humanized, usually the excavator is divided into upper and lower parts, we call the car part, the car part; The car is quite a human torso, it has a heart - the engine, someone's waist like the function - rotation, there is an arm like the work - work installation: big arm, two arms and digging bucket. And get off the car equivalent to human legs, mainly responsible for walking and turning the function of the whole machine.

The overall structure of the excavator includes power device, transmission system, control mechanism, rotating device, walking device, work installation, electrical equipment and auxiliary equipment

(1) Upper body part The upper body part is the main part of the hydraulic excavator, which is the installation platform of the main devices such as the power device, the hydraulic transmission system, the reversing mechanism, the working device, the cab and the auxiliary equipment. It is also a platform for generating power, transferring hydraulic force, and operating working devices to produce efficiency.

The upper body part is composed of an upper platform, a cab and an operating mechanism. The platform is installed with an engine, hydraulic pump, control valve, rotary mechanism, hydraulic oil tank, fuel tank, control oil circuit, electrical components, counterweight, working device and so on.

(2) Lower body part The lower body part is the supporting part and walking device of the whole machine of the hydraulic excavator, which bears all the weight of the machine and the reaction force of the working device, and can make the excavator travel a short distance.

The walking device of the hydraulic excavator is driven by hydraulic pressure. The driving device mainly includes hydraulic motor, reducer and driving wheel, and each track has its own hydraulic motor and reducer. Because the two hydraulic motors can be operated independently, so the left and right tracks of the machine can move forward or backward simultaneously, and can also realize turning through a track brake, and can also be driven by two tracks in the opposite direction to achieve in-situ steering. The operation is very simple, convenient and flexible.

The lower body part is divided into two categories according to the characteristics of structural design: track type and tire type. Taking the track type as an example, the main components are the central rotary joint, rotary support, X frame, track frame, tensioning device, walking motor, reducer, four wheels and one belt (support wheel, sprocket, drive wheel, guide wheel, track).

3. Three basic theoretical systems of excavators

The biggest feature of hydraulic excavator is the theory of hydraulic transmission. The hydraulic transmission system of the excavator is to transfer the power output of the diesel engine to the working device, the rotating device and the walking mechanism through the hydraulic system. Hydraulic excavator is mainly composed of three theoretical bases of mechanical principle, hydraulic principle and electrical principle as a whole, which is called the practical application of machine, electricity and hydraulic integration.

The main movements of the hydraulic excavator are the whole machine walking, the turntable turning, the boom lifting, the bucket rod retracting, the bucket rotating, etc. According to the above work requirements, the assembly that organically connects the hydraulic components with pipelines is called the hydraulic system of the hydraulic excavator. The function of the hydraulic system is to convert the mechanical energy of the engine to oil as the medium, use the hydraulic pump to transform into hydraulic energy, transfer to the hydraulic cylinder hydraulic motor and so on into mechanical energy, and then drive a variety of actuators to achieve a variety of movements. The hydraulic system of hydraulic excavator is commonly used in quantitative system, sub-power variable system and total power variable system. The total power variable system is the most commonly used hydraulic system for hydraulic excavator at present, and constant power variable double pumps are usually selected. The type of hydraulic pump is different, and the constant power regulating mechanism used is not the same.

1) The dynamic force system makes the diesel oil generator more than the mechanical process, especially the machinery with large tonnage and large power rate is based on the diesel oil machine. The basic structure of steam and oil generator is composed of two mechanisms and five systems, namely, crank linkage mechanism, gas distribution mechanism, fuel supply system, lubrication system, cooling system, ignition system and starting system. And diesel oil engine due to the use of different fuel, mixture formation and ignition methods are different, its basic structure is composed of two institutions, four systems, there is no oil converter, distributor, spark plug, and another oil injection pump and injector. Some diesel engines also add exhaust gas hole wheel supercharger.

(2) Hydraulic system

Hydraulic system is one of the main characteristics of the excavator, and it is also the important part of the hydraulic transmission system. The hydraulic system is usually composed of four component parts, and the liquid body (hydraulic oil) is the transmission medium to form a system whole body. The four component parts are: dynamic force element, execution element, control element and auxiliary element.

I. Dynamic force element. The mechanical energy is transformed into the hydraulic energy of the liquid element. For example, the hydraulic pump in the hydraulic system of the excavator plays this role. It provides hydraulic pressure for the hydraulic system.

II. Row element. The hydraulic energy of the liquid body is transformed into the hydraulic pressure element of the mechanical energy. The hydraulic cylinder installed in the excavator plays this role. Common in the hydraulic system is the hydraulic cylinder for linear reciprocating movement, or the hydraulic motor for rotary movement.

III. Control element parts. The element of controlling or adjusting the pressure force, flow volume and flow direction of the hydraulic system. Excavator control

The relief valve, reversing valve and balancing valve in the mechanism belong to such components. The hydraulic control valve in the hydraulic system is the control and adjustment element.

IV. auxiliary components. The above three parts are divided into other components. The oil tank and the oil absorption filter in the hydraulic pressure system of the excavator belong to this class of components. The oil tank, oil pipe, pipe connector, pressure gauge, filter and cooler in the hydraulic system

All are auxiliary components, which also play an important role in the normal operation of the assurance system

V. liquid pressure oil. In the hydraulic transmission installation, mineral oil is usually used as a working medium, which can not only transmit energy, but also lubricate the mechanism and parts of the hydraulic device. The pressure, flow rate and temperature of the liquid in the hydraulic system change in a wide range, the quality of the oil directly affects the work of the hydraulic system, because the study of the nature of the working liquid and the choice of the working liquid body are ten points of importance

(3) Electric gas control system Excavator electric gas control system is the general name of electric gas equipment and electrical control system. Its base is divided into two categories, one is the electric gas equipment, the main power source, starting machine, ignition system, only table, lamp lighting and signal equipment: The second is the electrical control system, the main sensor, the electric control unit, the executive structure of three parts.

1) Electrical and gas equipment. Electrical and gas equipment consists of electric source system, electrical equipment (starting system, ignition system, lighting installation, signal installation, auxiliary appliances), electrical monitoring device (all kinds of only meters, warning lights) and protection device (junction box, switch, safety device, connector, guide wire) Etc. Group

The power source system is composed of a storage pool, a generator, a controller and a working condition indicator (charging indicator).

As the main power source of the excavator in normal operation, the generator is responsible for supplying power to the electric devices except the starter, and charging the storage pool. The storage pool is used as the second power source of the excavator, the main power supply, and when the generator does not produce power or the power supply is insufficient, it is used as the auxiliary power supply. The output voltage of the generator is the same section. For adjustment, to keep the supply voltage constant. Working condition indicates that the installation is used to indicate the working condition of the power source system, the generator is usually generating power, the storage pool is in the charging state or discharge state, and the working voltage of the controller is normal.

2) the current control system. Excavator electrical control system is a high degree automatic, integrated control system with the computer as the center, and with the continuous increase of excavator power and gradually improve. The electronic control system includes two parts: hard

parts and soft parts, and the soft parts are divided by the machine itself

The hardware structure of the electronic control system of the excavator is generally composed of three parts; Signal input assembly, electronic control unit (ECU) and actuator,

I. signal input device. The main equipment of the signal input device is the sensor, and the sensor converts the physical parameters of the device into electrical signals (digital or analog) to monitor the operation of the device and environmental conditions. And these signals are transmitted to the electronic control unit. In other words, the sensor uses various electrical signals to reflect a virtual "mock-up device" that is identical to the actual device into the control system. The sensors can be thought of as the nerves of the control system.

II. Electronic control unit. The electronic control unit (ECU) receives and processes various information sent by the sensor, and analyzes this information,

To understand the condition of the device. Using a pre-determined control strategy, determine how to control the device in its current state and then translate this decision into one or more instructions for transmission to the actuator. The electronic control unit contains a microprocessor, and stores in the memory the program or control software prepared in advance by the designer. The electronic control unit can be thought of as the brain of the control system

III. Actuators. The actuator receives various instructions from the electronic control unit, and through its own design, the electrical signal is transformed into the action of the actuator (which can be the action of the electrical component, or a certain mechanical movement). The action of these components will change the operating conditions of the installation and determine the operation and output of the device. The solenoid valve is a form of the actuator.

The basic working process of the electronic control of the excavator: when the excavator is running, the sensors constantly detect the working condition information of the excavator, and transmit the information to the ECU through the input interface in real time. After receiving the information, the ECU makes corresponding decisions and processing according to the control program preprogrammed in the inner part, and outputs the control signal to the corresponding actuator through its output interface. After receiving the program signal, the actuator executes the corresponding action to achieve a certain predetermined function.

4. The software of excavator electronic control system

In the excavator electronic control system, in addition to the hardware equipment, it must also be equipped with certain software. The software includes system software and application software. System software is generally used less, and is only needed for special devices such as electronic maps. Such software is generally general-purpose. Such as DOS, Windbus operating system application software should be prepared by the excavator manufacturer according to the use of occasions and hardware.

Application software is a program compiled for the realization of control functions. Its core is the control program. The application software is mainly written according to the controlled object and control requirements, so it must be prepared by the excavator electronic control system designer.

In the excavator electronic control system, the control objects are not the same, so not only the hardware configuration of the control system itself is different, but also the system application software is different, but the control application software must meet the basic requirements of real-time, pertinence, flexibility, versatility and reliability.