Under the influence of the concepts of energy conservation and emission reduction and green environmental protection, more and more people begin to pay attention to the problem of automobile exhaust emission. As an air compressor, the turbocharger achieves the goal of increasing air intake by compressing the surrounding air. At the same time, turbochargers with the four advantages of improving engine power, improving engine emissions, providing plateau compensation, improving fuel economy and reducing fuel consumption are more and more widely used in more brands and types of vehicles due to their good performance, which has played a significant role in improving the lack of natural suction of traditional engines, It can increase the output power by 30% without changing the exhaust volume of the engine, which can actively promote energy conservation and emission reduction.
The structure of turbocharger is mainly composed of compressor and turbine. Specifically, the compressor is composed of diffuser, single-stage centrifugal compressor and compressor casing; The turbine consists of three parts: turbine, turbine shell and single-stage radial flow. In the internal structure, there are internal support rotor and full floating floating floating bearing located in the middle of the impeller. The axial force of the rotor mainly depends on the end face of the thrust ball bearing. In appearance, the turbine end and the compressor end are equipped with sealing ring devices. In addition, the compressor end in the turbocharger is separately equipped with oil baffle, which is mainly used to prevent the leakage of lubricating oil. The specific composition diagram is shown in Figure 1 and the internal structure diagram is shown in Figure 2.
The casting process of turbocharger pressure shell mainly includes mold selection, mold preheating, pouring and cooling forming. It is worth noting that in the preheating stage of the mold, the mold temperature machine should be used to stably provide enough heat for the selected mold, so as to control the temperature of the mold at about 300 ℃; When pouring the pressure shell, when pouring the metal liquid into the mold cavity, heat transfer occurs repeatedly with the mold cavity, which has reached the state of stable heat balance between the metal liquid and the mold cavity. In the process of core making, it is necessary to check whether the heating pipeline is connected properly, whether the temperature measuring thermocouple is connected properly, whether the air valve has air leakage and whether the pipeline is damaged; Avoid abnormal phenomena.
The melting of cast turbocharger aluminum alloy mainly includes five specific operation stages: proportioning of cast aluminum alloy melting, feeding of cast aluminum alloy, melting of cast aluminum alloy, refining and modification of cast aluminum alloy, and composition analysis of cast aluminum alloy. In the process of melting process, attention should be paid to the secondary pollution of melt. In order to ensure the quality of melt, it is necessary to first dry the furnace charge, refining agent, refining agent and all operation tools involved in the process in advance; Second, in order to avoid iron infiltration, the furnace charge shall ensure that sand, soil and other harmful substances are removed, and the iron tools used in the manufacturing process shall be coated as much as possible; Third, the smelting temperature, pouring temperature and pouring time should be strictly controlled in the smelting process to avoid the occurrence of too high temperature rise of molten aluminum and too long holding time. In addition, in order to improve the quality of metallurgy, pure aluminum or corresponding alloy can be used to wash the furnace before charging.