A plate mechanism of a pattern wheel knitting machine is provided with an improved lubricating system. The lubricating system has a groove formed on the contact surface between the plate and the gear of the machine for receiving balls therein. A flat liner ring is placed between the gear and the plate interior to the groove. The lubricating system is used, as the motor of the knitting machine starts the gear to rotate on the plate, to stabilize the gear, alleviate wear on the contact surfaces, and prolong the life of the knitting machine.