The hydraulic system of self loading mixer truck is generally divided into two categories: open system and closed system. The low-end brands in the current market mainly focus on open system, while the high-end brands mainly focus on the propulsion port closed system; The propulsion port closed system has a compact structure and high reliability. The following two structures are explained in detail for easy identification:
Double gear pump+cycloidal gear motor
Two constant displacement gear pumps. At low speed, the hydraulic pump supplies oil to the hydraulic motor; At high speed, the oil pump supplies oil to the hydraulic motor at the same time. The oil discharge of the hydraulic pump is different, mainly depending on the speed of high speed and low speed oil supply. The reversing valve controls the positive and reverse rotation of the mixing drum, and the overflow valve 7 plays an overload protection role. The overflow valve and one-way valve play the role of anti impact oil supplement protection.
Adjusting the speed through the throttle of the engine consumes a lot of energy and is not economical. Large oil tank is required and the structure is huge; The hydraulic oil is easy to mix with air, with large vibration and noise, poor reliability and short service life.
Axial piston variable displacement pump+constant displacement motor
Principle: The servo hydraulic cylinder controls the direction and inclination of the swashplate of the piston variable displacement pump to adjust the direction and displacement of the piston pump 3. High pressure relief valve can prevent system overload and play a protective role. The opening pressure of the two high-pressure relief valves can be adjusted according to the load of the oil circuit on both sides of the hydraulic motor to meet the requirements of different working conditions.
The rotary speed and steering direction are adjusted through the swashplate of the plunger variable displacement pump. The structure is compact, the tank volume is small, the heat dissipation requirements are high, the work is stable, the reliability is high, and the service life is long.
The explanation of the hydraulic system of the mixer is usually divided into two categories. It is recommended that you carefully check the hydraulic system in normal use to prevent problems from affecting the safety and quality of work. More relevant information can be found on our website https://www.zishangliaojiaobanji.cn Consult and understand!