Abstract: A ball screw device includes a screw shaft; a nut having a second helical groove; and a plurality of balls. When the screw shaft is rotated about an axis of the screw shaft while being subjected to the external force, the balls are displaced from positions under no load condition toward one side in an axial direction. A second helical groove of the nut includes a stopping member configured to prevent the balls from falling off from the second helical groove. A plurality of coil springs are arranged in series along the second helical groove. An angle in a circumferential direction occupied by each of the coil springs about the axis is 180 degrees or less when the coil springs are disposed in the second helical groove.

Abstract: A ball screw device includes a screw shaft; a nut having a second helical groove; and a plurality of balls. When the screw shaft is rotated about an axis of the screw shaft while being subjected to the external force, the balls are displaced from positions under no load condition toward one side in an axial direction. A second helical groove of the nut includes a stopping member configured to prevent the balls from falling off from the second helical groove. A plurality of coil springs are arranged in series along the second helical groove. An angle in a circumferential direction occupied by each of the coil springs about the axis is 180 degrees or less when the coil springs are disposed in the second helical groove.

Abstract: The rolling bearing includes an inner ring, and an outer ring which is arranged in a concave part which is formed in a fixing member so as not to rotate in a state preloaded in an axial direction toward the inner ring by way of a rolling element, with the fixing member at a bottom surface of the concave part. Moreover, a vibration isolating part formed of a laminated body including a pair of metal layers and a resin layer which is thinner than these metal layers and interposed between them is press clamped to be disposed between an end surface of the outer ring at a preloaded side in the axial direction and the bottom surface of the concave part, in such a manner that a direction of lamination may coincide with the axial direction.

Abstract: A tapered roller bearing is designed to have a roller loading ratio in the range of 0.7 to 0.92 and a ratio of roller length to roller diameter in the range of 1.1 to 1.7 whereby oil agitation loss and rolling viscous resistance are reduced for achieving the reduction of running torque. Crownings are provided which are designed to have an outer-ring crowning parameter (=RCO/LRO) in the range of 30 to 150 and an inner-ring crowning parameter (=RCI/LRI) in the range of 50 to 260, provided that RCO denotes the radius of an outer ring crowning, LRO denotes the raceway length of an outer ring, RCI denotes the radius of an inner ring crowning and LRI denotes the raceway length of an inner ring. Thus, the rolling viscous resistance is reduced for achieving the reduction of running torque.

Abstract: The rolling bearing includes an inner ring, and an outer ring which is arranged in a concave part which is formed in a fixing member so as not to rotate in a state preloaded in an axial direction toward the inner ring by way of a rolling element, with the fixing member at a bottom surface of the concave part. Moreover, a vibration isolating part formed of a laminated body including a pair of metal layers and a resin layer which is thinner than these metal layers and interposed between them is press clamped to be disposed between an end surface of the outer ring at a preloaded side in the axial direction and the bottom surface of the concave part, in such a manner that a direction of lamination may coincide with the axial direction.

Abstract: An end faced on an outer side in a radial direction of a small diameter annular portion of a retainer is disposed on an inner side in a radial direction of a pitch conical face of a taper roller and an end face on an inner side in a radial direction of a large diameter annular portion is disposed on an outer side in the radial direction of the pitch conical face. Further, a portion of the small diameter annular portion opposed to a small diameter end face of the taper roller is disposed on the inner side in the radial direction of the pitch conical face and a portion of the large diameter annular portion opposed to a large diameter end face of the taper roller is disposed on the outer side in the radial direction of the pitch conical face.

Abstract: The present invention relates to a bearing device for supporting a pinion shaft so as to freely rotate with respect to a case. The bearing device comprises a first tilt-contact rolling bearing provided on the connecting-flange-side outer peripheral surface of the pinion shaft and a second tilt-contact rolling bearing formed from an angular ball bearing provided on the pinion-gear-side outer peripheral surface of the pinion shaft, wherein lines of action of the first and second tilt-contact rolling bearings intersect with one another on an outer diameter side, the connecting-flange-side end portion of the first tilt-contact rolling bearing and the pinion-gear-side end portion of the second tilt-contact rolling bearing are respectively sealed with seal members, a sealed space between the seal members is infilled with grease, and the connecting flange is fastened in the pinion-gear direction to thereby preload the first and second tilt-contact rolling bearings.

Abstract: A tapered roller bearing includes: an outer race including an outer raceway surface; an inner race including an inner raceway surface and a larger collar surface which is a concave curved surface; and tapered rollers provided between the outer and inner races, each of the tapered rollers including a tapered surface and a larger end surface which is a convex curved surface communicating with the tapered surface and corresponds to the larger collar surface.

Abstract: A tapered roller bearing is designed to have a roller loading ratio in the range of 0.7 to 0.92 and a ratio of roller length to roller diameter in the range of 1.1 to 1.7 whereby oil agitation loss and rolling viscous resistance are reduced for achieving the reduction of running torque. Crownings are provided which are designed to have an outer-ring crowning parameter (=RCO/LRO) in the range of 30 to 150 and an inner-ring crowning parameter (=RCI/LRI) in the range of 50 to 260, provided that RCO denotes the radius of an outer ring crowning, LRO denotes the raceway length of an outer ring, RCI denotes the radius of an inner ring crowning and LRI denotes the raceway length of an inner ring. Thus, the rolling viscous resistance is reduced for achieving the reduction of running torque.

Abstract: A tapered roller bearing device has an inner ring 1, an outer ring 2, tapered rollers 3, a retainer 5 and a shield plate 6. The inner ring 1 has a flange portion 1a brought in contact with minor diameter end surfaces of the tapered rollers 3. The shield plate 6 is placed brought in contact with an end surface of the flange portion 1a of the inner ring 1. The shield plate 6 has a protrusion 9 that protrudes radially outwardly of the flange portion 1a. The protrusion 9 is placed in a place having an interval from the retainer 5 in an axial direction of the inner ring 1.

Abstract: An end faced on an outer side in a radial direction of a small diameter annular portion of a retainer is disposed on an inner side in a radial direction of a pitch conical face of a taper roller and an end face on an inner side in a radial direction of a large diameter annular portion is disposed on an outer side in the radial direction of the pitch conical face. Further, a portion of the small diameter annular portion opposed to a small diameter end face of the taper roller is disposed on the inner side in the radial direction of the pitch conical face and a portion of the large diameter annular portion opposed to a large diameter end face of the taper roller is disposed on the outer side in the radial direction of the pitch conical face.

Abstract: A tapered roller bearing includes: an outer race including an outer raceway surface; an inner race including an inner raceway surface and a larger collar surface which is a concave curved surface; and tapered rollers provided between the outer and inner races, each of the tapered rollers including a tapered surface and a larger end surface which is a convex curved surface communicating with the tapered surface and corresponds to the larger collar surface.

Abstract: The present invention relates to a bearing device for supporting a pinion shaft so as to freely rotate with respect to a case. The bearing device comprises a first tilt-contact rolling bearing provided on the connecting-flange-side outer peripheral surface of the pinion shaft and a second tilt-contact rolling bearing formed from an angular ball bearing provided on the pinion-gear-side outer peripheral surface of the pinion shaft, wherein lines of action of the first and second tilt-contact rolling bearings intersect with one another on an outer diameter side, the connecting-flange-side end portion of the first tilt-contact rolling bearing and the pinion-gear-side end portion of the second tilt-contact rolling bearing are respectively sealed with seal members, a sealed space between the seal members is infilled with grease, and the connecting flange is fastened in the pinion-gear direction to thereby preload the first and second tilt-contact rolling bearings.

Abstract: Bearing parts are formed of damping steel containing 0.2 to 0.6 wt. % C, 5.0 to 15.0 wt. % Cr, 0.2 to 1.3 wt. % Si, 0.05 to 0.20 wt. % N, and comprising Fe and inevitable impurities as the remaining. The damping steel may be hardened in an ordinary manner to have a surface hardness, in terms of Rockwell C hardness of at least 57.

Abstract: A joint structure of an annular member and a shaft member softer than the former is produced by(a) providing a shaft member with an oil spreading over its circumference, the shaft member having a plurality of discrete grooves, on its circumference in an inclined angular configuration about the axis of the shaft member, and(b) press fitting the annular member to the bore of the annular member with an interference such that the inner periphery of the annular member bore meshingly expands into the grooves. Press fitting proceeds under resilient deformation of the inner periphery of the annular member in the boundary friction state. A continuous oil film remains on the mating surfaces while securing firm joint.