The periodicity of motor disassembly maintenance in railway vehicles is currently determined by the durability of the sealed grease they contain. The lifetime of this grease is the shortest of all the motor's bearing parts and materials, and therefore needs to be made longer. To this end, therefore, the authors discussed the shape of the grease pocket, and concluded that the efficiency of lubrication depends on the shape of the pocket and the relative position between pockets and the bearing, which should be appropriately modified. In this report, the authors first introduce examples of the improved grease pocket shape together with the results of laboratory testing on the base-oil behavior, then show the results of laboratory tests using full-scale grease pocket models with conventional and modified shapes to compare the service lives and determine the effects of improvement.