The first domestically produced positive flow hydraulic excavator was successfully developed

Recently, the first domestically produced positive flow system hydraulic excavator was successfully tested in the Sany Kunshan Industrial Park and will soon be mass-produced. This marks the entry of the Sany excavator into the positive flow system from the negative flow system, which also marks the first level of China's excavator production level entering the world.

The development of the positive flow excavator began in early 2006. From the initial market research and project to the technical design, from the construction drawing design to the installation and commissioning of the whole machine, the excavator research institute has invested in the most elite research and development. In the prototype test phase, the company's leaders adhered to the spirit of excellence, and put forward high requirements for the test plan and the technical indicators of the whole machine. After several trials and improvements, the positive flow excavator has both internal quality and appearance. It has reached the international level.

The excavator is a high-power earth-rock machine. The core technology of the excavator is mainly focused on power dynamic matching and effective use, in order to realize the unification of excavator power and economy. Among them, the real-time matching of the flow rate of the hydraulic system is one of the main core technologies of the hydraulic excavator.

At present, mainstream international excavators generally adopt negative flow hydraulic systems. Negative flow systems can achieve dynamic matching of hydraulic system flow, but have shortcomings such as long response time, large flow fluctuations, and poor operability. In recent years, with the advancement of technology in the field of hydraulic control, it has become possible to achieve positive flow control of the hydraulic system of the excavator. The Trin Excavator Research Institute actively adopts the latest international technological achievements. After more than half a year of technical research, it has finally developed the first positive-flow system hydraulic excavator in China. After several tests and improvements, the current working efficiency of the machine is lower than that of the negative-flow excavator. It has increased by about 8%, the energy consumption has dropped by about 10%, the operation comfort and the smoothness of the movement have been greatly improved, and the working performance is comparable to that of the world's top excavators. The cost of the machine is basically the same as that of the negative flow excavator, which has a high cost performance.

The machine adopts imported diesel engine, which meets Euro II emission standard; the hydraulic system adopts positive flow system, which is characterized in that the displacement of the main pump is proportional to the signal pressure output by the pilot operating handle. The main controller judges the flow demand of the actuator and its changing trend according to the pilot pressure signal and its changing trend, and adjusts the displacement of the main pump accordingly, so that the flow supply of the system can dynamically follow the flow demand of the actuator, and realize the system. The real-time matching of traffic reaches “required and required”. The system has a small loss of bit flow in the relative negative flow system, and the reliability of the relative load sensitive system is high.

The machine adopts a new controller to carry out new electric-hydraulic control of the whole machine, through engine throttle position feedback, engine speed monitoring, power limit adjustment and other electronic control means (ESS control) and main pump positive flow control, linear travel proportional control, rotary Hydraulic control means (HSS control) such as priority proportional control and bucket confluence proportional control, which can match the engine power with the hydraulic pump power in real time, improve the productivity of the operation, reduce the fuel consumption, and realize the computer dynamic following control of the external output power demand of the host output power ( CDCS), which achieves the optimal control of the excavator-external load operating system, is the perfect combination of excavator power and economy.

The machine has three power modes, four operating modes, fault self-diagnosis function, GPS global positioning function and GPRS data transmission system, remote monitoring and fault diagnosis function, built-in training system and excavator auxiliary maintenance system and safety alarm system.