Oil injection lubrication With the further increase of the operating speed, the resistance of the FAG machine tool spindle bearing with symmetrical section to the lubricating oil increases continuously. If a larger amount of circulating oil is planned, during the high-speed operation of the bearing, the lubricating oil is injected into the gap between the cage and the bearing ring. The oil splash loss of oil injection lubrication is small. Normal oil quantity can be determined by speed parameters and bearing size. In this case, please consult the engineering service department of Qingdao Ruijing Electromechanical Equipment Co., Ltd. The accumulation of oil in front of the bearing is prevented by a little oil spray that can freely enter the bearing. The correct front and rear dimensions of the oil outlet ensure that the oil is not consumed in the bearing and that the oil can flow freely out of the bearing. Pressure Loss and Injection Velocity Oil-injection lubrication enables high-speed operation, proven lubricants are CLP or HLP compliant, viscosities ranging from u003d 46 mm2/s to 68 mm2/s or 100 mm2/s, in order to achieve viscosities ratio u003d 2. The curves give oil quantity and injection velocity as a function of pressure drop, nozzle diameter and operating viscosity, see Figure 4. These data are obtained through testing. The flow rate of lubricating oil through rapidly rotating bearings decreases with increasing rotational speed. Increasing the injection speed can increase the oil flow rate, 30 m/s is the recommended upper limit. Nozzle length L u003d 8.3 mmV u003d Oil volume flow (oil volume) p u003d Pressure drop v u003d Injection velocity D u003d Nozzle diameter Working viscosity u003d 7.75 mm2/s Working viscosity u003d 15.5 mm2/s Figure 4 Pressure loss and injection velocity 00018021. Design considerations NMB rolling bearings must be lubricated immediately after the machine is started. For circulating oil lubrication, the oil pump starts to supply oil before the bearing starts. For safety reasons, it is better to design an additional oil tank for the circulating oil lubrication system. Even if the oil pump is broken, the oil can be supplied through the oil tank. At low temperatures, the circulating oil volume can be at the minimum allowable value. This is maintained until the original value is restored after the tank heats up. Design of circulating oil lubrication system (oil pump drive, oil return system). If large oil volumes are used for lubrication, the outlet design must prevent oil accumulation, which usually occurs at high speeds and results in large energy losses. The diameter of the oil outlet pipe depends on the oil viscosity and the drop angle of the oil discharge pipe. If several NTN bearings are used in combination, the corresponding oil quantity must be determined for each individual bearing. Attention must be paid to the lubrication of radial cylindrical roller bearings, please refer to Super Precision Bearings Catalogue SP 1. In most cases, radial cylindrical roller bearings are fully lubricated by the amount of oil in the upper bearing.