Abstract: A centerless grinding processing in which a sliding contact surface (10) is subjected to grinding by pressing a grindstone against the sliding contact surface (10) of an inner ring (3) while rotating the inner ring (3) relative to the grindstone in a prescribed direction, and then, in the centerless grinding process, a finishing step in which grinding lines in a direction intersecting grinding lines formed on the sliding contact surface (10) are formed on the sliding contact surface (10) and/or processing for improving the surface roughness of the sliding contact surface (10) is performed is performed.

Abstract: A bearing unit for a wheel hub assembly for motor vehicles, having a first raceway which is a radially outer and axially outer raceway and a second raceway which is a radially outer and axially inner raceway, a third raceway which is a radially inner and axially outer raceway and a fourth raceway which is a radially inner and axially inner raceway; an axially outer row and an axially inner row of rolling bodied, interposed, respectively, between the first raceway and the third raceway and between the second raceway and the fourth raceway; at least one raceway is provided with a first raceway portion and a second raceway portion, the raceway portions being tangential to the rolling body of the row of rolling bodies at two different contact angles the first contact angle of the first raceway being smaller than the second contact angle of the second raceway portion.

Abstract: A rolling bearing includes: an inner ring; an outer ring; a plurality of balls provided between an inner ring raceway and an outer ring raceway; and an annular cage in which the balls are held at intervals in the circumferential direction of the cage. The cage includes an annular body, a plurality of first cage prongs, and a plurality of second cage prongs. A radially outer part of each of the first cage prongs includes a recessed portion. The recessed portion is constituted by a region surrounded by a first side wall surface, a second side wall surface, a bottom wall surface, and a third side wall surface.

Abstract: A dental handpiece and method of turbine support therein, comprises a turbine wheel having a rotor shaft rotatably supported by a housing via ball bearings, and configured to rotationally drive a clamping chuck, at least one of the ball bearings including, an inner ring arranged on the rotor shaft, the inner ring having a raceway, an outer ring, having an outer raceway movably supported by the housing, and balls arranged between and guided by the inner and outer raceways. The raceway of the inner ring, in cross section, has a concave shape with a curvature corresponding to a radius of the balls. Optionally, the raceway of the outer ring in cross section, has, in a central area, a first curvature with a first radius and, adjoining the central area, a second curvature with a second radius, the first radius being smaller than the second. Optionally, the raceway of the outer ring has a substantially parabolic profile.

Abstract: A double-row four-point contact ball bearing 100 according to the present invention includes an outer ring 102, an inner ring 104, and balls 106 and 108 that are arranged in two rows between the outer ring 102 and the inner ring 104 and each have four contact points. Inner side contact angles ? of the balls 106 and 108 arranged in the two rows are set such that lines of action L1 and L2 that extend respectively connecting center points of the balls 106 and 108 and contact points of the balls do not cross each other in the outer ring 102.

Abstract: The invention relates to universal machine parts, and more particularly to a curved groove ball bearing without a retainer, which can solve the problems in the prior at such as high pendulating frequency and small amplitude. For the bearing, an inner ring and an outer ring are respectively provided with a first curved groove and a second curved groove, where “peaks” and “valleys” of the first curved groove are respectively the same as those of the second curved groove in number. The second curved groove is filled with steel balls, and a retainer for fixing the relative positions of the steel balls is removed, increasing the amplitude and reducing the pendulating frequency.

Abstract: An angular contact ball bearing includes an outer ring having an outer diameter D and a first rolling surface and an inner ring having an inner diameter d and a second rolling surface, and no more than one row of balls between the first rolling surface and the second rolling surface, each of the balls having a diameter Dw. The diameter Dw of the balls, the outer diameter D of the outer ring, and the inner diameter d of the inner ring satisfy the relationship: D w > 0.7 * ( D - d ) 2 .

Abstract: A submersible pump includes a bearing arrangement and a rotor shaft. The bearing arrangement includes a bearing cover, a bearing flange, and one or more bearing elements, each bearing element having an inner bearing ring, an outer bearing ring and a roller element. The rotor shaft is rotatably supported in the one or more bearing element about an axis of rotation extending in a longitudinal axial direction so that the inner bearing ring is configured to rotate along with the rotor shaft in an operating state. The bearing element is arranged at the bearing flange such that the bearing cover tensions each outer bearing ring in a longitudinal axial direction and such that a peripheral gap having a predefined axial width is formed in a radial direction between the outer bearing ring and the bearing cover and between the outer bearing ring and the bearing flange.

Abstract: An angular contact ball bearing includes an outer ring having an outer diameter D and a first rolling surface and an inner ring having an inner diameter d and a second rolling surface, and no more than one row of balls between the first rolling surface and the second rolling surface, each of the balls having a diameter Dw. The diameter Dw of the balls, the outer diameter D of the outer ring, and the inner diameter d of the inner ring satisfy the relationship: 2 ? D w D - d > 0.7 .

Abstract: There is provided a method for processing a raceway groove configured to circumferentially form a to-be-processed side raceway groove on a surface to be processed of a workpiece, the to-be-processed side raceway groove is configured to be brought into rolling contact with a rolling element, and the surface to be processed is a cylindrical circumferential surface. The method for processing a raceway groove includes: arranging a processing rolling element rotatably between the to-be-processed side raceway groove and a tool side circumferential surface which is opposed to the surface to be processed and which is a cylindrical circumferential surface of a machining tool; rotating the machining tool relatively with respect to the workpiece; and performing a burnishing process on the to-be-processed side raceway groove.

Abstract: A ball bearing not allowing locations where the surface pressure becomes locally higher at a race at the time of a high load and thereby keeping cracking from occurring and in turn realizing a longer lifespan is provided. A pair of races (12, 14) and at least one rolling element (16) movably clamped between the pair of races move are provided. A cross-sectional profile line (14a) of a part of each of the pair of races contacting the rolling element has the smallest radius of curvature at a position (P) sticking out the most in the first direction (D1) over which the pair of races face. The cross-sectional profile line becomes larger in radius of curvature the further from the position (P) in a second direction (D2) vertical to the first direction (D1) in the cross-section. The cross-sectional profile line is comprised of a single function.

Abstract: The invention comprises methods and systems for moving gaming machines. Preferably, the positions of two or more movable gaming machines are controlled, such as to synchronously control their movement.

Abstract: A bearing constructed in accordance to one example of the present disclosure includes at least one inner bearing ring, at least one outer bearing ring, at least one rolling element and a direct metal deposition (DMD) raceway architecture. The DMD raceway architecture is disposed between the at least one inner and outer bearing rings. The DMD raceway architecture includes an inner DMD structure that defines an inner raceway and an outer DMD structure that defines an outer raceway. The inner and outer raceways are configured to support the at least one rolling element.

Abstract: A wheel bearing apparatus for rotatably supporting a wheel includes an inner member having two rows of raceway grooves on its outer circumference, an outer member having two rows of raceway grooves on its inner circumference, and rolling elements interposed between the raceway grooves of the inner and outer members. The raceway grooves of the inner and outer members are formed by hardened steel cutting. In relation to at least the raceway groove on the outboard side out of the raceway grooves of the inner member, h/d exceeds 0.50 where h is the depth of the groove and d is the diameter of the rolling elements. This provides a wheel bearing apparatus being compact and capable of withstanding a high applied load without inviting an increase in the size of the bearing.

Abstract: A wheel bearing apparatus has a double row angular contact ball bearing. A height of a shoulder of a shoulder portion (18) of an outer member (12) with respect to a ball diameter of a double ball (14) row is set in a range of 0.35 to 0.50 mm. A corner (19) of the shoulder portion (18) has a relief surface (19a) and a chamfered portion (19b). The relief surface is on a straight line that is on a tangent line of an outer raceway surface (12a). The chamfered portion (19b) is round in a circular arc with a predetermined radius of curvature r. The corner (19) is formed simultaneously by a formed grinding wheel forming the double row outer raceway surface (12a). The corner is formed smoothly continuous from each outer raceway surface (12a). A length in the radial direction of the relief surface (19a) is set greater than or equal to 0.2 mm.

Abstract: A bearing for providing rotation of at least one intermediate part relative to a first part and a second part includes a first bearing race formed in the first part, the first bearing race having a raceway corresponding to a first diameter, and a second bearing race and a third bearing race formed in the at least one intermediate part, the second bearing race and third bearing race having a raceway corresponding to a second diameter, wherein the first diameter is different from the second diameter. Further, a fourth bearing race is formed in the second part, the fourth bearing race having a raceway corresponding to the first diameter. A first plurality of roller elements are arranged between the first raceway and the second raceway, and a second plurality of roller elements are arranged between the third raceway and the fourth raceway.

Abstract: A rotary electric machine includes a stator core; a rotor that includes a laminated core, core holders, and cooling fans; a frame that includes a tubular unit that encloses the stator core and the rotor, and a first bracket and a second bracket that extend in a direction of a rotor shaft and supports the rotor shaft; and cartridges that are detachably attached to the first bracket and the second bracket and rotatably supports the rotor shaft, wherein groove-like or hole-like holding portions, which hold end portions of bearing attaching and detaching jigs inserted through the first bracket and the second bracket, are provided in the cooling fans.

Abstract: A ball bearing having first and second races and, disposed in a gap between the two races, a row of balls of radius RK that roll along facing tracks of the two races, wherein centers of the balls move on a circular path surrounded by a torus circumscribing all the balls of the row and having the toroidal radius RK, a toroidal angle coordinate ?, and a poloidal angle coordinate ?, wherein each track has with each ball two nearly punctiform contact areas P1, P2; P3 P4 at respective contact angles ?P1, ?P2; ?P3 and ?P4, wherein the cross section of the track in the region of the contact points P1 . . . P4 has a finite transverse radius of curvature RL1 . . . RL4, with RLv>RK, and wherein in the vicinity of a contact point P1 . . . P4 the transverse radius of curvature (RL) is a continuous and differentiable function of the poloidal angle coordinate ?: RL=RL(?) that increases outward from the respective contact point P1 . . . P4 in both poloidal directions: RL(?)?RL(?Pv).

Abstract: A method of manufacturing a bearing ring of a rolling bearing includes a process of forming a bearing ring material in which a raceway groove is formed, a process of performing form rolling so as to form surface textures in axially opposite end portions of the raceway groove, a heat treatment process, a grinding process, and a super-finishing process.

Abstract: In a bearing for vertical axis windmill configured to rotatably support a vertical axis of a vertical axis windmill, the bearing includes a ball (7), a diameter of the ball and a curvature of a rolling groove of the bearing are set to satisfy a predetermined starting torque and a load rating. For example, the curvature of the rolling groove of the bearing is 54% or more and 100% or less, and the diameter of the ball has a ratio of 20% or less with respect to a vertical shaft (2).

Abstract: A bearing includes an inner ring, an outer ring, and a plurality of rolling elements. In the bearing, each of an inner ring raceway surface and an outer ring raceway surface has a contact area that comes into contact with the rolling elements, and a non-contact area that is formed adjacent to an outer side of an end portion of the contact area and does not come into contact with the rolling elements. A lubricant retaining portion having a recessed portion and a large number of non-uniform projections and depressions is formed at the non-contact area of at least one of the inner ring raceway surface and the outer ring raceway surface.

Abstract: A rotation support device for a pinion shaft is configured such that, together with being able to sufficiently maintain axial rigidity of a rolling bearing on the side opposite from the pinion gear side, it is able to sufficiently reduce the dynamic torque during operation and the starting torque at the start of operation. Together with using a single-row angular contact ball bearing as the rolling bearing on the side opposite from the pinion gear side, the ratio of the radius of curvature Ro of the outer raceway and the diameter Bd of the balls (Ro/Bd) is regulated within the range 0.52<Ro/Bd?0.56, and the contact angle ? is regulated within the range of 35° to 40°.

Abstract: An asymmetric wheel hub assembly with two rows of rolling elements of different pitch diameters has a central axis of rotation and inner raceway and outer raceways for each row of elements, the associated inner and outer raceways being axially displaced in accordance with a respective angle of contact and along a respective load line such that the assembly is capable of accommodating combined loading. The raceways of each row of rolling elements have osculation ratios which are defined by the ratio between the radius of curvature of the raceways and the outside diameters of the rolling elements of the associated row of rolling elements. The angle of contact and the osculation ratios of a first one of the two rows of the rolling elements is different than the angle of contact and osculation ratios of a second one of the two rows of the rolling elements.

Abstract: A wheel hub assembly with two rows of rolling elements has a central axis of rotation and inner raceway and outer raceways for each row of elements, the associated inner and outer raceways being axially displaced in accordance with a respective angle of contact and along a respective load line such that the assembly is capable of accommodating combined loading. The raceways of each row of rolling elements have osculation ratios which are defined by the ratio between the radius of curvature of the raceways and the outside diameters of the rolling elements of the associated row of rolling elements. The osculation ratios of a first one of the two rows of the rolling elements are different than the osculation ratios of a second one of the two rows of the rolling elements.

Abstract: A vehicle wheel bearing apparatus has an outer member, an inner member, and double row balls contained between the outer and inner raceway surfaces and adapted to be applied a predetermined contact angle. Each inner raceway surface is formed by a first circular arc section, with a first radius of curvature (r), that extends from a position near a contact point contacting the ball at an initial contact angle (?) to the raceway bottom. The second circular arc section, with a second radius of curvature (r1) smaller than the radius of curvature r, extends from an inflection point that the ball contacts at a contact angle (?1) to the radially outer side. The (r) and (r1) are set as 1.05 d<2 r?1.10 d and 1.01 d<2 r1?1.05 d (“d” is a diameter of the ball). ?? is in a range of 2° to 8° when the inflection point of the radii of curvatures r, r1 is positioned at ?1=?+?? (?=30-45°).

Abstract: A wheel hub assembly with two rows of rolling elements has a central axis of rotation and inner raceway and outer raceways for each row of elements, the associated inner and outer raceways being axially displaced in accordance with a respective angle of contact and along a respective load line such that the assembly is capable of accommodating combined loading. The raceways of each row of rolling elements have osculation ratios which are defined by the ratio between the radius of curvature of the raceways and the outside diameters of the rolling elements of the associated row of rolling elements. The angle of contact and the osculation ratios of a first one of the two rows of the rolling elements are different than the angle of contact and osculation ratios of a second one of the two rows of the rolling elements.

Abstract: A rotation urging mechanism includes an outer member which includes an outer raceway surface on an inner periphery thereof and is rotatable about a first axis, an inner member which includes, on an outer periphery thereof, an inner raceway surface disposed on a radially inner side of the outer raceway surface and is rotatable about the first axis, and a ball disposed rollably between the outer raceway surface and the inner raceway surface. One of the outer and inner raceway surfaces is formed about a second axis which is inclined with respect to the first axis, and the other raceway surface is formed about a third axis which is inclined with respect to the second axis and is disposed so as to cross the one raceway surface. The ball is disposed at a portion of intersection between the outer and inner raceway surfaces.

Abstract: A tandem set of angular contact ball bearings each having an inner ring, an outer ring and balls therebetween, wherein each bearing contains balls that are spaced from each other by slug ball separators. A rotary wing aircraft rotor head assembly includes a rotor head member, a plurality of spindles attached to the head member at equal interval around the center of the head member, and a stack of ball bearings mounted on each spindle. Each bearing has an inner ring, an outer ring, and a plurality of balls between the inner ring and the outer ring, and slug ball separators between adjacent balls, and there is a mounting collar on the ball bearings.

Abstract: A retainer made of a synthetic resin for use in a deep groove ball bearing is proposed of which the lubricity has been improved. The retainer includes a cylindrical first split retainer member (41) having a first axial side, and a cylindrical second split retainer member (42) having a second axial side coupled to the first axial side of the first split retainer member (41). Circumferentially spaced apart first and second cutouts (45 and 50) are formed in the first axial side of the first split retainer member (41) and the second axial side of the second split retainer member (42), respectively, which define respective pockets for receiving balls with the split retainers (41 and 42) coupled together.

Abstract: A rolling bearing slewing connection comprising two race rings arranged concentrically in each other, between which race rings rolling elements roll on associated raceways, one of the race rings having a flexible configuration wherein, as viewed in a longitudinal section, the flexible race ring has a weakened configuration, so that a radial, elastic deformation that is so large that the rolling elements are pre-stressed in the loaded state in the entire peripheral region is possible.

Abstract: Provided are a retainer capable of achieving torque reduction, a deep-groove ball bearing with the retainer, and a sealed bearing capable of preventing intrusion of foreign matter into the bearing and capable of sufficient seal torque reduction. The retainer is formed by combination of two annular retaining plates (27A, 27B) each including semispherical swelling portions (26) arranged at predetermined intervals along a circumferential direction. The semispherical swelling portions (26, 26) face each other and form pockets (30) for retaining balls (16). Each of the pockets (30) has ball-facing surfaces each including a ball non-contact portion (31), and a contact area in each of the pockets (30) with respect to each of the balls (16) is reduced by from 15% to 30% in comparison with a contact area with respect to each of the balls (16) without provision of the ball non-contact portion (31).

Abstract: The difference between a revolution period of larger diameter-side balls and a revolution period of smaller diameter-side balls is smaller as compared with a conventional bearing. The relation, (??10)??<?, is established, where ?(°) represents a contact angle of the larger diameter-side ball, and ?(°) represents a contact angle of the smaller diameter-side ball.

Abstract: A vehicle wheel bearing apparatus has an outer member formed, on its inner circumference, with double row outer raceway surfaces. An inner member is formed on its outer circumference surface, with double row inner raceway surfaces arranged opposite to the double row outer raceway surfaces. Double ball groups are freely rollably contained between the outer raceway surfaces and inner raceway surfaces, respectively, of the outer member and the inner member. It is formed as a double row angular contact ball bearing of back-to-back duplex type where a predetermined contacting angle is applied to each ball. A pitch circle diameter of the outer-side ball group is larger than a pitch circle diameter of the inner-side ball group. The outer-side groove diameter of curvature ratios are smaller than inner-side groove diameter of curvature ratios.

Abstract: The radial antifriction bearing has an outer bearing ring, an inner bearing ring and roller bodies, which are arranged between the bearing rings, are held at uniform distances from one another in the peripheral direction by a bearing cage. The roller bodies are discs that each have two parallelly arranged lateral surfaces which are symmetrically flattened from a spherical basic shape. In order to prevent edge stresses between the discs and the raceways, at least the raceway in the inner bearing ring, on its outer edge areas, transition into a logarithmically decreasing profile.

Abstract: The invention relates to a bearing for a wind turbine comprising bearing rings with raceways, and at least one row of bearing balls or rollers positioned between said raceways. At least one of said raceways comprises one or more indentation areas in relation to a standard shape of the raceways. The invention also relates to a wind turbine and methods for manufacturing a bearing.

Abstract: A rotation urging mechanism includes: an outer member which has an outer raceway surface on its inner periphery and is rotatable about a first axis; an inner member which has on its outer periphery an inner raceway surface disposed in face-to-face relation to a radially inner side of the outer raceway surface over an entire circumference thereof and is rotatable about the first axis; and a plurality of balls disposed rollably between the outer raceway surface and the inner raceway surface. The outer raceway surface is formed about a second axis which is inclined with respect to the first axis, and the inner raceway surface is formed about a third axis which is inclined with respect to the first axis.

Abstract: The invention relates to a bearing for a wind turbine comprising bearing rings with raceways, and at least one row of bearing balls or rollers positioned between said raceways. At least one of said raceways comprises one or more indentation areas in relation to a standard shape of the raceways. The invention also relates to a wind turbine and methods for manufacturing a bearing.

Abstract: A rotation support device for a compressor pulley, wherein a three-point contact radial ball bearing (14b) is used as a rolling bearing for supporting a driven pulley, the cross sectional shape of an inner ring raceway track (19b) coming into contact, at one point, with the rolling contact surface of each ball (17a) is formed in a composite arc by smoothly and continuously connecting arcs with different radii of curvature R1 and R2 to each other, and the radius of curvature R1 on a center side in the width direction is made smaller and the radii of curvature R2 on the both end sides in the width direction are made larger (R1<R2) whereby the durability of the rolling bearing for supporting the driven pulley can be assured while reducing the size of the rolling bearing.

Abstract: A roughness of an outer ring raceway surface 14 formed on an inner peripheral surface of an outer ring 13 is made larger than a roughness of inner ring raceway surfaces 12a, 12b of an inner ring 11. Also, an average roughness Ra of the outer ring raceway surface 14 is set within 0.1 ?m?Ra?0.5 ?m in an axial direction and a circumferential direction in ranges of b1/(B/2)?0.9, b2/ (B/2)?0.9 and in a measured length of 0.1 mm to 1.0 mm where B is a width of the outer ring 13 and b1, b2 are a distance from both end surfaces of the outer ring 13 in the axial direction respectively. A roughness parameter S of the outer ring raceway surface is set within 0<S?20 ?m.

Abstract: A vacuum pump includes a high-speed rotor, and an anti-friction bearing for rotatably supporting the rotor and including an inner ring, an outer ring, a rolling body, and a cage for the rolling body both the rolling body and the cage being located in an intermediate space defined by the outer and inner rings, with the cage having a threaded groove in a section of its surface adjacent to the inner ring for insuring a continuous feeding of a lubricant to the bearing.

Abstract: A bearing includes an inner race having a rotational axis and an outer race sharing the rotational axis of the inner race. Rolling bearing members are constrained between the inner race and the outer race. A retention lip is provided which is adapted to maintain a peripheral opening of a constant gauge distance between and prevent relative axial movement of the inner race and the outer race. The gauge distance of the peripheral opening is adapted to allow free passage of the rolling bearing members, upon wear on the rolling bearing members reaches a predetermined level. The bearing provides a pass or fail indication, by falling apart when the rolling bearing members have exceeded the predetermined level of wear.

Abstract: In a rolling bearing structured such that a plurality of rolling elements are respectively held between inner and outer rings by a retainer, grease is sealed in by a seal, a rotary body with the outer ring fitted therewith and a shaft with the inner ring fitted therewith can be connected together by a clutch mechanism and, when the rotary body and shaft are connected together by the clutch mechanism, the rolling bearing can be used on receiving a rotation load while the relative rotation between the inner and outer rings is zero, an initial radial clearance between the inner and outer rings is set such that a bearing effective clearance when the present rolling bearing is incorporated into between the rotary body and shaft can provide a positive value.

Abstract: A ball bearing stack which includes more than one bearing arranged in face to face relation and sharing a common rotational axis. Each bearing has an inner ring and a concentric outer ring. The inner ring defines an inner race. The outer ring defines an outer race. A plurality of ball bearings are captured within an annular space defined between the inner race and the outer race. Each of the more than one bearing has a ball bearing contact surface on the outer race which is radiused from face to face about a common centre point positioned on the common rotational axis.

Abstract: An innovative parabolic profiled rolling grooves for linear guide way is disclosed. Cross sectional profile of at least one of the ray-way and the slider grooves is configurated into a parabolic curve so as to avoid the balls to comprehensively contact the grooves and seriously increase the frictional loss. With the rolling grooves constructed as such, the mechanical durability and the loading ability can be definitely improved.

Abstract: A hub bearing assembly comprising a hub having a radially outwardly directed flange at one axial end for mounting the wheel of a vehicle, an outer ring having axially spaced raceways and a plurality of rolling elements arranged in two rows in the annular space between the outer ring and the hub, the diameter of the pitch circle of the outboard row of rolling elements adjacent said flange being greater than the diameter of the pitch circle of the rolling elements in the inboard row.

Abstract: An outer ring 3a is formed so as to have a large thickness and the pitch circle diameters Dp of balls 6 are shifted to the inside diameter side of the present ball bearing. The radiuses of curvature Ro, Ri of the section shapes of an outer ring raceway 2a and an inner ring raceway 4a are increased with respect to the diameter Db of the balls 6. At the same time, the diameter Db of the balls 6 and the thickness of an inner ring 5a are not set excessively small to thereby be able not only to prevent Brinell impressions from being formed in the outer ring raceway 2a but also to prevent the inner ring 5a from being damaged or cracked.

Abstract: A play-free rotary mounting for a drive roll held on stop surfaces in the axial direction on a cylindrical body, wherein V-shaped annular grooves with an opening angle V are provided at least in one of the end faces of the drive roll and the stop surface located opposite them on the body, V-shaped bearing shells with at approximately identical opening angles and approximately identical leg length are inserted into the annular grooves, the vertex diameters of the annular grooves differ from the vertex diameters of the bearing shells. Balls with a diameter matched to the opening width of the bearing shells are inserted into the bearing shells. At least one of the stop surfaces can be adjusted in the axial direction in order to clamp the drive roll in. Instead of different vertex diameters, different opening angles can also be provided for the annular grooves and opening angles for the bearing shells.

Abstract: A non-permeable pipe connector structure, the design of which effectively prevents external material (such as vapor and miscellaneous substances, etc.) intrusion. To obstruct the intrusion of external matter into the pipe connector, a ball bearing holder is disposed at the pipe connector, enabling even greater ball bearing durability and, furthermore, free rotation. A protective flange is disposed as the bottom surface of the ball bearing holder such that when the coupling nipple and the connector base are fastened together, the protective flange effectively blocks external matter, thereby precluding entry to avert subsequent damage to the bearings. Furthermore, a rubber sealing ring sleeved onto the annular groove prevents vaporous or acid and alkaline substance intrusion into the bearings, and has safe defensive effectiveness.

Abstract: A rolling bearing has the radius of curvature of the raceway on an inner ring and an outer ring is from not smaller than 50.1% to not greater than 51.9% of the diameter of the balls, and at least one of the compositions of the bearing is obtained by forming an alloy steel having a carbon (C) content of from not smaller than 0.50% to not greater than 0.90%, a chromium (Cr) content of from not smaller than 3.0% to not greater than 15.0%, a manganese (Mn) content of from not smaller than 0.10% to not greater than 2.0%, a silicon (Si) content of from not smaller than 0.10% to not greater than 2.0%, a molybdenum (Mo) content of zero or not greater than 2.0% by weight, and a vanadium (V) content of zero or not greater than 2.0%, by weight.

Abstract: A power roller bearing of a toroidal-type continuously variable transmission unit that is used for a transmission of an automobile or the like comprises a power roller, an outer race, balls, a retainer, etc. Annular raceway grooves are formed individually on the respective opposite end faces of the outer race and the power roller. Treated-surface layers for enhancing the endurance of the power roller bearing are formed individually on the respective surfaces of the raceway grooves. The treated-surface layers include super-finished surfaces with the surface roughness of 0.05 Rad or less, formed individually on the raceway grooves, and low-friction layers formed individually on the super-finished surfaces. Alternatively, the treated-surface layers include residual compression stress layers formed on the respective surface layer portions of the raceway grooves by shot-preening.