What Is Mobile Hydraulic Technology?
Mobile hydraulic technology is a hydraulic technology used in mobile equipment. It uses liquid (usually hydraulic oil) to transfer energy in a closed system to drive mechanical parts to complete various tasks.
1. Basic Principle
Pascal's Law
The basic principle of mobile hydraulic technology is based on Pascal's Law: the pressure applied to a stationary liquid can be evenly transmitted to all parts of the liquid. For example, in a hydraulic system consisting of a small piston and a large piston, when a small force is applied to the small piston, the pressure generated by this force is transmitted to the large piston through the hydraulic oil. According to Pascal's Law, the pressure is equal throughout the liquid. Since the area of the large piston is larger than that of the small piston, a much larger force will be generated on the large piston than the force applied on the small piston, thereby achieving force amplification.
The formula is expressed as P=F/A (where P is pressure, F is force, and A is area). In a hydraulic system, P1 = P2, F1/A1=F2/A2, can be designed according to the needs of pistons of different areas to achieve force amplification or reduction.
Energy Conversion
Mobile hydraulic systems mainly involve the mutual conversion of mechanical energy and hydraulic energy. When the hydraulic pump works, it converts mechanical energy (usually provided by the engine or motor) into hydraulic energy by pressurizing the hydraulic oil and making it flow in the system. Then, the hydraulic energy is converted back into mechanical energy in the actuators such as hydraulic cylinders or hydraulic motors to drive the load to move. For example, in the working device of the excavator, the engine drives the hydraulic pump, which pressurizes the hydraulic oil and delivers it to each hydraulic cylinder. The hydraulic cylinder converts the hydraulic energy into mechanical energy, pushes the stick, boom, and other parts to move, and realizes the excavation action.
2. Main Components
Power Element
The hydraulic pump is the power element of the mobile hydraulic system. Its function is to convert mechanical energy into hydraulic energy. Common hydraulic pumps include gear pumps, vane pumps, and plunger pumps.
The gear pump has a simple structure and reliable operation. It is mainly composed of a pair of meshing gears. When the gear rotates, the volume between the teeth changes continuously, realizing the process of oil suction and oil pressure. It is generally used in low-pressure, small, and medium-flow hydraulic systems, such as some small agricultural machinery or simple industrial equipment.
Vane pumps are divided into single-acting vane pumps and double-acting vane pumps. Double-acting vane pumps have the advantages of uniform flow and small-pressure pulsation and are widely used in medium-pressure hydraulic systems, such as machine tools, construction machinery, and other equipment.
The plunger pump achieves oil suction and oil pressure through the reciprocating motion of the plunger in the cylinder. It has the characteristics of high pressure, high efficiency, and convenient flow regulation. It is often used in high-pressure, large-flow hydraulic systems, such as large construction machinery and mining machinery.
Actuator
Hydraulic cylinders and hydraulic motors are actuators of mobile hydraulic systems, which convert hydraulic energy into mechanical energy. Hydraulic cylinders are mainly used to achieve linear motion, such as bucket lifting of loaders and lifting of dump truck compartments. It consists of cylinder barrels, pistons, piston rods, and other components. When hydraulic oil enters one chamber of the hydraulic cylinder, it pushes the piston and piston rod to move, thereby achieving linear displacement.
The hydraulic motor is used to achieve rotational motion. For example, in the mixing drum drive of a concrete mixer truck, the hydraulic motor converts hydraulic energy into rotational mechanical energy to drive the mixing drum to rotate. According to different structures, hydraulic motors can be divided into gear type, vane type, and plunger-type. Different types of hydraulic motors are suitable for different working requirements and load characteristics.
Control Elements
Hydraulic valves are elements that control the pressure, flow, and direction of hydraulic oil in hydraulic systems. Pressure control valves are used to control the pressure in hydraulic systems. For example, overflow valves can limit the maximum pressure of the system to prevent system overload; pressure-reducing valves can reduce the pressure in the system to the required working pressure.
Flow control valves are used to adjust the flow of hydraulic oil. For example, throttle valves can control the flow by changing the flow cross-sectional area, thereby controlling the movement speed of the actuator. Direction control valves are used to control the flow direction of hydraulic oil. For example, electromagnetic reversing valves can change the position of the valve core through electromagnetic force, thereby changing the flow direction of hydraulic oil, so that the actuator can achieve forward and reverse or stop actions.
Auxiliary Elements
Includes oil tanks, oil pipes, pipe joints, filters, etc. The oil tank is used to store hydraulic oil, and it also plays a role in heat dissipation and precipitation of impurities. Oil pipes and pipe joints are used to connect various components in the hydraulic system to ensure that the hydraulic oil can flow smoothly in the system. The filter is used to filter impurities in the hydraulic oil to prevent impurities from entering the hydraulic pump, hydraulic valve, and actuator to ensure the normal operation of the system.
3. Application Fields
Engineering Machinery Field
It is widely used in excavators, loaders, bulldozers, cranes, and other equipment. Taking the excavator as an example, the movements of its boom, dipper, and bucket are all driven by mobile hydraulic systems. The equipment uses the powerful power and precise control capabilities of the hydraulic system to efficiently complete tasks such as excavation, loading, and handling at complex construction sites.
Agricultural Machinery Field
For example, the suspension system of tractors, the lifting and conveying devices of the header of combine harvesters, etc. all use mobile hydraulic technology. In agricultural machinery, mobile hydraulic systems can flexibly adjust the position and movement of mechanical parts according to the height of crops, the texture of soil, etc., to improve agricultural production efficiency.
Transportation Field
Including the lifting device of the carriage of dump trucks, the lifting mechanism of truck cranes, and the working devices of some special vehicles. For example, dump trucks use hydraulic systems to quickly and stably lift the carriage to unload goods, greatly improving transportation efficiency.
Aerospace Field
Mobile hydraulic technology is also used in the aircraft's landing gear retraction system, flap and slat drive system, and other parts. These systems require high reliability and precision, and mobile hydraulic technology can meet their working requirements in complex flight environments.