Abstract: In an electric power steering apparatus, an intermediate member of a shaft coupling connecting an assisting electric motor and a speed reduction mechanism together includes a cylindrical intermediate boss portion, a plurality of arm portions extending radially from the intermediate boss portion, and engagement spaces each defined by a pair of the adjacent arm portions. Furthermore, the intermediate member includes a center portion, a first cover portion, and a second cover portion. The center portion slightly protrudes toward the engagement space side with respect to the first cover portion and the second cover portion.

Abstract: In an electric power steering apparatus, an intermediate member of a shaft coupling connecting an assisting electric motor and a speed reduction mechanism together includes a cylindrical intermediate boss portion, a plurality of arm portions extending radially from the intermediate boss portion, and engagement spaces each defined by a pair of the adjacent arm portions. Furthermore, the intermediate member includes a center portion, a first cover portion, and a second cover portion. The center portion slightly protrudes toward the engagement space side with respect to the first cover portion and the second cover portion.

Abstract: A telescopic shaft (5) has an inner shaft (12) and a tubular outer shaft (13) that are fitted to each other so as to be relatively movable in an axial direction (X1) and to be able to transmit torque between each other. A row of a plurality of rolling bodies (14) is interposed between corresponding axial grooves (15, 16) of the inner shaft (12) and the outer shaft (13). A retaining member (17) moving together with the rolling bodies (14) while retaining the rolling bodies (14) has a facing portion (33) facing an end surface (121) of the inner shaft (12). As the telescopic shaft (5) telescopes in and out, the facing portion (33) comes into contact with the end surface (121) of the inner shaft (12), and this limits the movement of the rolling bodies (14) in the axial direction (X1).

Abstract: A universal joint yoke includes: a cylindrical portion for fixing a shaft; a slit that is formed in the cylindrical portion and that extends from one end of the cylindrical portion in an axial direction of the cylindrical portion, which is a first direction; a reinforcement flange that extends from the other end of the cylindrical portion radially outward with respect to the cylindrical portion; and a pair of arms that extend from the reinforcement flange on a side opposite to a side on which the cylindrical portion is provided and that are swingably coupled to another yoke via a coupling shaft.

Abstract: A lubricant composition contains poly-?-olefin oil having a kinematic viscosity of 1500 to 13000 mm 2/s (40° C.) as a base oil and from 45 to 50% by weight of a thickener composed of polytetrafluoroethylene. The lubricant composition may be used for lubricating an expandable shaft having a pair of shaft members filled with the lubricant composition to prevent stick-slip from occurring when a high surface pressure is applied thereto, thereby allowing consistent maintenance of good lubricating performance. Such an expandable shaft may be incorporated advantageously into a steering system as an intermediate shaft into an area between a steering shaft and a rack-and-pinion mechanism.

Abstract: A telescopic shaft (5) has an inner shaft (12) and a tubular outer shaft (13) that are fitted to each other so as to be relatively movable in an axial direction (X1) and to be able to transmit torque between each other. A row of a plurality of rolling bodies (14) is interposed between corresponding axial grooves (15, 16) of the inner shaft (12) and the outer shaft (13). A retaining member (17) moving together with the rolling bodies (14) while retaining the rolling bodies (14) has a facing portion (33) facing an end surface (121) of the inner shaft (12). As the telescopic shaft (5) telescopes in and out, the facing portion (33) comes into contact with the end surface (121) of the inner shaft (12), and this limits the movement of the rolling bodies (14) in the axial direction (X1).

Abstract: A universal joint yoke includes: a cylindrical portion for fixing a shaft; a slit that is formed in the cylindrical portion and that extends from one end of the cylindrical portion in an axial direction of the cylindrical portion, which is a first direction; a reinforcement flange that extends from the other end of the cylindrical portion radially outward with respect to the cylindrical portion; and a pair of arms that extend from the reinforcement flange on a side opposite to a side on which the cylindrical portion is provided and that are swingably coupled to another yoke via a coupling shaft.

Abstract: A lubricant composition contains a base oil having a kinematic viscosity of 1500 to 13000 mm2/s (40° C.) and polytetrafluoroethylene serving as a thickener, and is used for lubricating an expandable shaft to prevent stick-slip from occurring when a high surface pressure is applied thereto, thereby allowing to maintain a good lubricating performance consistently. The expandable shaft 5 has a pair of shaft members 51 and 52 filled with the lubricant composition. In a steering system 1, the expandable shaft 5 is incorporated as an intermediate shaft into an area between a steering shaft 3 and a rack-and-pinion mechanism A.