Patent ID: 7481197

Claim:
A lubrication device of four-stroke engines, which is applicable to a four-stroke engine that has a cylinder, a crank case, a rocker arm room and a cam room connected to the rocker arm room, the crank case having a crankshaft that is divided into a crankshaft first section, a connection part and a crankshaft second section, the cylinder having a piston connecting rod connected to the connection part, the lubrication device comprising: a lubricant tank connected to a bottom of the crank case for containing lubricant; a stirring chamber allocated beneath the crank case and partially located inside the lubricant tank, the stirring chamber having at least one oil hole in communication with the lubricant tank; an oil stirring rod allocated at one end of the piston connecting rod and received in the stirring chamber for stirring lubricant to oil mists; an oil supply path having a pipeline connected to the rocker arm room and the crank case, and an oil supply channel allocated inside the crankshaft first section and correspondingly connected to the pipeline and interior of the crank case, the oil supply channel being open when the crankshaft first section rotates to a first rotation angle, so as to supply the oil mists through the rocker arm room to the cam room; and an oil recycling path including an oil recycling channel allocated inside the crankshaft second section and correspondingly connected to the interiors of the cam room and the crank case, the oil recycling channel being open when the crankshaft second section rotates to a second rotation angle different from the first rotation angle, so as to re-absorb the oil mists into the crank case.