A method of and device for enabling automatic and timely feeding of lubricant to mechanisms of a machine driven by a motor. An amount of increase in driving electric current for the mold-clamping servomotor (12) in the course of change from an appropriate lubrication state to an inappropriate one in the mold-clamping mechanism (10) of an injection molding machine is predetermined for every combination of the kind of an injection molding machine, conditions for injection molding, and kind of grease. Then, while executing a normal injection molding cycle in an appropriate lubrication state, a standard value of current to drive the motor is determined on the basis of motor driving normal current in a specific position to which a movable platen (14) having performed current measurement for the above-said predetermination is displaced and an increase in motor driving current so that the standard value and the specific position to which the movable platen is displaced are stored in the memory of a numerical control device (50). The control device, in response to grease feeding time judging instruction, drives a grease pump (40) when a detected motor current in the specific displaced position of the movable platen exceeds the standard value. Grease from the grease pump is distributed to each of a plurality of parts of the mold clamper in quantity as required through a distributor (43).

The present invention provides a control method of an automatic lubrication system of a variable-pitch bearing used for a wind turbine generator system (WTGS). The method comprises the following steps: calculating a current friction factor of the variable-pitch bearing using a current friction moment of the variable-pitch bearing of WTGS; determining a demand of lubrication grease according to the operation power of WTGS and the current friction factor of the variable-pitch bearing, wherein the friction factor of the variable-pitch bearing to be obtained is taken as an objective; customizing a lubrication control strategy according to the demand of lubrication grease, wherein a predetermined energy production of WTGS is taken as an objective; calculating lubrication target regions according to an average wind speed and a power of an wind turbine, the lubrication target regions being operation regions of the tooth surfaces of the variable-pitch bearing; meanwhile, calculating an angle difference between grease discharge points of a lubrication pinion and the lubrication target regions; moving the angle difference by an actuator of a variable-pitch system under the control of the main controller of the WTGS, and carrying out automatic lubrication according to the control strategy. The present invention has the advantage that good lubrication is realized for the variable-pitch bearing and variable-pitch tooth surfaces.