This kind of bearing with retainer is not prepared in advance and then assembling, but in bearing joint and separate rolling body evenly mix of ultra-high molecular weight polyethylene with grease, after filling the bearing internal space, then heated to form cage. In this kind of cage grease firmly fixed by resin material, for the past due to leakage of grease bearing life is reduced, and the problems of pollution on environment nearby grease, this surely is the ideal bearing products. As NTN company exclusive development of products, according to the oil filling quantity comes in two forms: one is the type of trace oil, it contains is necessary for bearing lubrication grease the minimum; Another is in great measure oil supply type, cage materials (PE mixture with grease) bearing internal space filling full. Both trace oil supply type and quantity of oil supply more type, its characteristic is common: (1) the leakage of the grease rarely for grease is along with the increase in factors such as bearing heating, centrifugal force maintains a precipitate and gradually to the rotation surface supply, therefore, the leakage of the grease. Compared with general grease lubrication method, which can effectively prevent pollution to the environment. (2) the lubrication good performance even violent vibration or large centrifugal force, acting on the bearing grease is difficult to leak, won't make emulsified grease flowing out with water intrusion, so is superior than the general grease lubrication characteristics. (3) bearing way of rotational torque small traces of oil bearing almost no grease of shearing resistance, bearing the rotational torque is small. (4) the seal retainer against foreign invasion object (moisture, dust, etc.) have certain resistance, but in it as a seal or not sufficient, especially for those who are particularly high sealing performance requirements, or to adopt contact rubber seal (such as deep groove ball bearings, bearing units) or other form of sealing structure.