This invention belongs to the field of
crankshaft technology, and specifically relates to a
crankshaft, its manufacturing method, and its applications. The
crankshaft of this invention includes a crankshaft body and a composite layer disposed on the surface of the crankshaft body; the composite layer includes a nitrided layer, a
phosphate layer, and a lubricating layer arranged sequentially from the inside out. The nitrided layer improves the fatigue strength and
wear resistance of the crankshaft. The
phosphate layer formed on the nitrided layer serves as a base layer, providing a good adhesion foundation for the lubricating layer and improving the bonding between the
phosphate layer and the lubricating layer, i.e., improving the bonding between the lubricating layer and the crankshaft body, allowing the lubricating layer to better perform its function of reducing friction and wear. When the crankshaft-bearing friction pair enters the
boundary lubrication state, the lubricating layer is consumed first, forming a
solid lubrication transfer film on the
bearing surface. This avoids direct contact between the crankshaft's nitrided layer and the bearing, while also achieving a friction-reducing and lubricating effect, thus improving the wear of the crankshaft-bearing friction pair.