Titanium alloy metal injection molding automotive piston MIM parts

Titanium alloy metal injection molding automotive piston MIM parts

Piston structure

The entire piston can be mainly divided into three parts: piston crown, piston head and piston skirt.

The main function of the piston is to withstand the combustion pressure in the cylinder and transmit this force to the crankshaft through the piston pin and connecting rod. In addition, the piston, together with the cylinder head and cylinder wall, form a combustion chamber.

The piston top is an integral part of the combustion chamber, so it is often made into different shapes. Most gasoline engine piston tops are flat or concave in order to make the combustion chamber compact, with a small heat dissipation area and a simple manufacturing process. Raised top pistons are commonly used in two-stroke gasoline engines. The piston top of a diesel engine is often made into various pits.

The piston head is the part above the piston pin seat. A piston ring is installed on the piston head to prevent high-temperature and high-pressure gas from escaping into the crankcase and prevent oil from escaping into the combustion chamber. Most of the heat absorbed by the top of the piston also passes through the piston head. is transmitted to the cylinder and then transmitted away through the cooling medium.

The piston head is machined with several annular grooves for installing piston rings. The number of piston rings depends on the sealing requirements, which is related to the engine speed and cylinder pressure. The number of rings of high-speed engines is less than that of low-speed engines, and the number of rings of gasoline engines is less than that of diesel engines. Generally, gasoline engines use 2 air rings and 1 oil ring; diesel engines use 3 air rings and 1 oil ring; low-speed diesel engines use 3 to 4 air rings. In order to reduce friction loss, the height of the ring belt should be reduced as much as possible, and the number of rings should be reduced while ensuring sealing.

Everything below the piston ring groove is called the piston skirt. Its function is to guide the piston to reciprocate in the cylinder and withstand side pressure. When the engine is working, the piston will bend and deform due to the gas pressure in the cylinder. After the piston is heated, the piston pin expands more than other parts because there is a lot of metal. In addition, the piston will also produce extrusion deformation under the action of lateral pressure. The comprehensive result of the above deformation makes the piston skirt section become an ellipse with the long axis perpendicular to the direction of the piston pin. In addition, because the temperature and mass distribution of the piston along the axis are uneven, the thermal expansion of each section is larger at the top and smaller at the bottom.

Qinhuangdao Zhongwei Precision Mechanical Parts Co., Ltd. mainly uses metal (or non-metal) powder near net forming and injection molding processes to engage in the research and development, production, sales and value-added services of new materials and their products. Through the continuous improvement of new material technology and processing technology Innovation, development and reserve to lead the upgrading of traditional industries, import substitution and the development of emerging fields. The company's main business application fields are divided into powder metallurgy press forming process application fields, powder injection molding and liquid metal process application fields and soft magnetic composite material application fields. Among them, the powder metallurgy injection molding process application fields are: fuel vehicles, new energy vehicles, high-efficiency vehicles Energy-saving home appliances, power tools, etc.; powder injection molding and liquid metal process application fields are: automobiles, consumer electronics, communications, bathroom, etc.; soft magnetic composite material application fields are: new energy vehicles, photovoltaics, power supplies, filters, communications, motors wait.