There are mainly two kinds of ball pin structures: one is the combination of ball pin and integral ball seat, and the other is the combination of hemispherical ball pin and spherical member. In the past, coil springs were mostly used to preload and compensate wear, but now synthetic resin ball seats with elasticity and lubrication are widely used, which not only reduces the cost, but also improves the handling stability. In addition, the material and shape of the dust cover and the type of grease are greatly improved, the grease nozzle is cancelled, and the maintenance free structure is realized.

The ball joint pin is mainly composed of end cover, ball pin, ball seat and dust cover

End caps are mostly steel plate stamping parts, which are mainly made of carbon steel, and some are also made of aluminum alloy or nodular cast iron.

The machining accuracy of the ball pin surface is high. Alloy steel with good hardenability is mostly used. The surface of the ball pin matched with the metal ball needs surface hardening treatment such as high-frequency quenching to improve the wear resistance. At present, the ball pin is mostly matched with the non-metallic ball socket, so only the ball pin needs to be quenched and tempered. The selection of ball pin diameter shall be comprehensively considered according to tensile strength, durability and other factors.

The ball socket is made of case hardened steel, powder metallurgy, nylon, polyacetal resin, polyurethane and polyester elastomer. Because the material and shape of the ball socket have a great impact on the wear and fatigue life, the material is immersed in molybdenum disulfide or oil to improve the wear resistance. Reinforcing ribs or composite materials can also be added on the ball seat.

The tightness of the dust cover has a great influence on the wear and fatigue life of the ball pin. The materials are polyurethane or neoprene with high temperature resistance, oil resistance and aging resistance. In addition, the deformation during its movement shall be considered in the design to prevent dust from entering the ball joint pin from the mating surface after deformation. At the same time, the matching accuracy between the dust cover and related parts also has a great impact on the tightness and service life.