Patent ID: 8302737

Claim:
A main-shaft lubrication device comprising: a plurality of bearings supporting a main shaft; a plurality of lubricant oil supply pipes corresponding in number to the plurality of bearings, each lubricant oil supply pipe supplying lubricant oil to a corresponding one of the plurality of bearings; a plurality of supply means corresponding in number to the plurality of bearings, each of the plurality of supply means being operatively associated with a corresponding one of the plurality of lubricant oil supply pipes for variably supplying lubricant oil to one of the plurality of bearings; a plurality of lubricant oil collection pipes corresponding in number to the plurality of bearings, each lubricant oil collection pipe being in fluid communication with and collecting lubricant oil from a corresponding one of the plurality of bearings; a plurality of collection means corresponding in number to the plurality of bearings, each of the collection means being in fluid communication with a corresponding one of the plurality of lubricant oil collection pipes for drawing the lubricant oil from each of the plurality of bearings into the corresponding one of the lubricant oil collection pipes at constant suction force; a plurality of measurement means corresponding in number to the plurality of bearings, each of the measurement means being operatively associated with a corresponding one of the plurality of lubricant oil collection pipes for measuring the amount per unit time of lubricant oil collected by the collection means from the corresponding one of the plurality of bearings and providing a measurement value thereof; and control means for calculating amounts of lubricant oil to be supplied for each bearing based on the amount per unit time of lubricant oil provided by each of the plurality of measurement means and a predetermined amount of lubricant oil supply per collected amount, and controlling each of the plurality of supply means to supply the calculated amount of lubricant oil to each of the plurality of bearings.