Abstract: Provided is a power transmission device including a housing and a ball screw device including a nut housed in the housing. The device includes a screw shaft passing through the nut, and balls disposed between the nut and the screw shaft. The device also includes a first bearing and a second bearing that are disposed to be adjacent to each other in a center axis direction parallel with a center axis of the nut between the housing and the nut; and a preload applying member constituted of an elastic body and configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing respectively include outer rings that are fitted to the housing and separated from each other in the center axis direction, and the first bearing and the second bearing are disposed to be a face-to-face combination.

Abstract: A power transmission device including a housing and a ball screw device including a nut, a screw shaft, and a plurality of balls. The device includes a pulley device including a driving pulley configured to be driven by receiving power transmitted from a power source, a driven pulley fixed to the nut, and a belt wound around outer peripheral surfaces of the driving pulley and the driven pulley. The device also includes a first bearing and a second bearing disposed between the housing and the nut in a center axis direction parallel with a center axis of the nut; and a preload applying member configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing are respectively disposed on both sides of the driven pulley to be a face-to-face combination, and each of the first bearing and the second bearing includes an outer ring engaged with the housing.

Abstract: It is an object of the present invention to provide a thrust ball bearing which has a large load capacity, can realize thinned wall, and can further withstand a radial load. A pair of raceways (21, 22) include double rows of raceway grooves (23A, 23B) provided along a radial direction on surfaces facing each other. The retainer (40) includes claw-shaped protrusions (42) that protrude from peripheral edges of openings of pockets (41) in a convex manner and are arranged to face each other only in a circumferential direction of the retainer. A maximum width W of the claw-shaped protrusions (42) in the radial direction is smaller than a maximum width L of the raceway grooves (23) in the radial direction.

Abstract: An outer ring (2) is provided with a stationary ring-side flange (2a) along a circumferential direction. The stationary ring-side flange (2a) is provided with a plurality of mounting holes (2b) which is arranged at unequal intervals and which is used to fasten the outer ring (2) to a knuckle (N) through knuckle bolts (Bt). The stationary ring-side flange (2a) includes first flange part (30) located in a region in which a distance between adjacent mounting holes (2b) is larger and second flange part (40) located in a region in which a distance between adjacent mounting holes (2b) is smaller. A radial thickness of the first flange part (30) is a greater than a radial thickness of the second flange part (40).

Abstract: An outer ring (2) is provided with a stationary ring-side flange (2a) along a circumferential direction. The stationary ring-side flange (2a) is provided with a plurality of mounting holes (2b) which is arranged at unequal intervals and which is used to fasten the outer ring (2) to a knuckle (N) through knuckle bolts (Bt). The stationary ring-side flange (2a) includes first flange part (30) located in a region in which a distance between adjacent mounting holes (2b) is larger and second flange part (40) located in a region in which a distance between adjacent mounting holes (2b) is smaller. A radial thickness of the first flange part (30) is a greater than a radial thickness of the second flange part (40).

Abstract: A structure which ensures a movement of a seal lip disposed in a seal lip is realized by preventing foreign matters from permeating a seal internal space between a slinger and a seal ring. A labyrinth seal is disposed between an outer peripheral edge of a rotary side annular portion configuring the slinger and an inner peripheral surface of a stationary side cylindrical portion of a metal insert configuring the seal ring. In addition, a thickened portion is formed in a portion of an elastic member configuring the seal ring over an entire periphery. An auxiliary seal lip whose rigidity is lower than that of respective seal lips is disposed in the thickened portion over the entire periphery. The auxiliary seal lip prevents the foreign matters from adhering to the seal lip, and prevents the movement of the seal lip from being hindered.

Abstract: A structure which can ensure a movement of a seal lip 22a disposed in a seal lip 17a is realized by preventing foreign matters from permeating a seal internal space 26a between a slinger 16 and a seal ring 17a which configure a combination seal ring 12a. A labyrinth seal 27a is disposed between an outer peripheral edge of a rotary side annular portion 19 configuring the slinger 16 and an inner peripheral surface of a stationary side cylindrical portion 23 of a metal insert 20 configuring the seal ring 17a. In addition, a thickened portion 29 is formed in a portion of an elastic member 21 a configuring the seal ring 17a over an entire periphery. An auxiliary seal lip 32 whose rigidity is lower than that of respective seal lips 22a to 22c is disposed in the thickened portion 29 over the entire periphery. The auxiliary seal lip 32 prevents the foreign matters from adhering to the seal lip 22a, and prevents the movement of the seal lip 22a from being hindered.

Abstract: A construction is adopted in which an annular spacer 27 is held between first and second inner races 2a, 2b. An internal clearance in a double-row bearing unit is measured in a middle step of assembling work of a wheel supporting bearing assembly, and in the event that a resultant measured value does not become a proper value, an axial dimension of the spacer 27 is adjusted, so that the internal clearance becomes the proper value. Thereafter, the assembling work is made to continue until the assembling work is completed. A problem which is to be solved by the invention is solved in the way described above.

Abstract: A radial roller bearing has: an outer ring; an inner ring; and, a cylindrical roller interposed between the outer ring and the inner ring, the outer and inner rings respectively including flange portions formed in the end portions thereof so as to be opposed to the end face of the cylindrical roller, wherein, in the end face of the cylindrical roller, there is formed a circular-ring-shaped contact portion of the roller end having centers of curvature continuously existing on a circle which lies on a plane parallel to the end face of the cylindrical roller and also the center of the circle is on the rotation axis of the cylindrical roller.

Abstract: A radial roller bearing has: an outer ring; an inner ring; and, a cylindrical roller interposed between the outer ring and the inner ring, the outer and inner rings respectively including flange portions formed in the end portions thereof so as to be opposed to the end face of the cylindrical roller, wherein, in the end face of the cylindrical roller, there is formed a circular-ring-shaped contact portion of the roller end having centers of curvature continuously existing on a circle which lies on a plane parallel to the end face of the cylindrical roller and also the center of the circle is on the rotation axis of the cylindrical roller.

Abstract: A radial roller bearing has: an outer ring; an inner ring; and, a cylindrical roller interposed between the outer ring and the inner ring, the outer and inner rings respectively including flange portions formed in the end portions thereof so as to be opposed to the end face of the cylindrical roller, wherein, in the end face of the cylindrical roller, there is formed a circular-ring-shaped contact portion of the roller end having centers of curvature continuously existing on a circle which lies on a plane parallel to the end face of the cylindrical roller and also the center of the circle is on the rotation axis of the cylindrical roller.

Abstract: A radial roller bearing has: an outer ring; an inner ring; and, a cylindrical roller interposed between the outer ring and the inner ring, the outer and inner rings respectively including flange portions formed in the end portions thereof so as to be opposed to the end face of the cylindrical roller, wherein, in the end face of the cylindrical roller, there is formed a circular-ring-shaped contact portion of the roller end having centers of curvature continuously existing on a circle which lies on a plane parallel to the end face of the cylindrical roller and also the center of the circle is on the rotation axis of the cylindrical roller.