Abstract: A hydrodynamic bearing device incorporates a relatively rotatable shaft 1 and a sleeve 2 internally sealed with the shaft 1. A groove for generating dynamic pressure is formed on an external circumferential surface of the shaft 1 or on internal circumferential surface of the sleeve 2. A circumferential groove 1a is formed at one end of the shaft 1 external to the bearing. An annular sealing plate 3 is secured to the sleeve 2 and interegagging with the shaft 1 external to the bearing and the circumferential groove 1a. A labyrinth is formed between the inner-diametric domain of the sealing plate 3. An annular recessed domain 2c is defined by internal circumferential surface of the sleeve 2 and the sealing plate 3 at a position substantially opposite the circumferential groove 1a. An oil-pooling space 4 thereby formed by the shaft 1, the circumferential groove 1a, the sleeve 2, the sealing plate 3, and the annular recessed domain 2c.

Abstract: An oil seal comprises a seal body, a lip, and a plurality of ribs provided on a bevel facing a space without oil when the inner circumference of the lip is utilized. The plurality of ribs are included an angle with respect to the rotational direction of a shaft. Rear ribs with respect to the rotatational direction are set longer than the front ribs. Effecive oil recovery is enabled by the rib structure from the front ribs to the rear ribs.

Abstract: The present invention provides a grease composition comprising a lubricating oil and a thickener, characterized in that the thickener is a diurea compound prepared by reacting a diisocyanate compound with cyclohexylamine and monoalkylphenylamine wherein the alkyl portion has 8 to 16 carbon atoms.

Abstract: A sealed type rolling bearing includes an another race, an inner race, a plurality of rolling elements, at least one retainer therefor, and at least one seal plate. The bearing is sealed with grease seal, and grease in the bearing is prevented from flowing at a high rate by means of an annular projection extending radially inwardly from the retainer defining a small gap defined between the projection of the retainer and the inner race.

Abstract: An improved tapered roller bearing in which a shoulder at a small diameter end side of an inner race has been eliminated. A shoulder portion for maintaining a state of engagement between an inner race and a cage for holding tapered rollers at circumferentially equally spaced positions after assembling, is formed at an outer peripheral portion of a large diameter side of the inner race. Furthermore, projections for engagement with the shoulder portion are formed in positions not hindering the assembling of the tapered rollers at the large diameter side of the cage.

Abstract: A rust preventive oil comprising a base oil having a viscosity of from 10 to 20 centistokes at 40.degree. C. which consists of from 70 to 80 percent by weight of low viscosity mineral oil and from 10 to 20 percent by weight of high viscosity mineral oil and additives such as barium sulphonate, wax or ester thereof, amine, higher alcohol, antioxidant and non-corrosive extreme pressure additive is beneficially suited for the high precision low frictional touque tapered roller bearing.