Abstract: The designing of an annular integral type is established by forming a cage of a resin material that satisfies the condition (a) that the ratio of its linear expansion coefficient to that of bearing steel is not more than 2 or the condition (b) that its water absorption percentage is not more than 0.5%, or both conditions (a) and (b), thereby preventing the occurrence of abnormal sounds by stabilizing the behavior of a segment type cage for an ultrathin-walled rolling bearing.

Abstract: The radius of curvature r1, r2 of the cross-sectional shape of an inner ring raceway 11d is made smaller at a central portion 19 and larger at end portions 20. A contact ellipse at the end portions is made small by increasing the radius of curvature r2 of the end portions 20 to thereby secure an allowable moment load. In contrast with this, an angular gap is reduced by reducing the radius of curvature r1 of the central portion 19.

Abstract: The present invention provides a roller bearing in which a plurality of rollers is interposed between an inner ring member and an outer ring member, and a flange having a guide surface for guiding an end surface of the roller in a sliding contact manner is provided at an end portion of at least one of the inner ring member and outer ring member in an axial direction. Three-dimensional surface roughness of the end surface of the roller is defined to a value which satisfies conditional expressions of Sa≦0.1 &mgr;m and 0.15 &mgr;m≦Svk≦0.30 &mgr;m, where Sa is arithmetical average roughness based on rough curve and Svk is reduced valley depth based on the rough curve.

Abstract: An assembly method of a preload-adjustable rolling bearing unit comprising the steps of providing a shaft having a first inner raceway, an inner ring being press fitted onto the shaft and having a second inner raceway, such that a pitch of both raceways is set greater than a pitch required to give a predetermined preload, providing an outer ring having outer raceways, providing a plurality of balls to be fitted between the outer raceways of the outer ring, and the first and second inner raceways, positioning the balls equidistant apart in the circumferential direction, and vibrating the rolling bearing unit by means of piezo electric elements while moving the inner ring in the axial direction, measuring the resonant frequency of the rolling bearing unit with a vibration sensor to control the preload whereby the inner ring is pressed onto a shaft while vibrating with only a small amount of energy without scratching the raceway and rolling surfaces.

Abstract: A radial ball bearing 14 of the three point contact type or four point contact type is used for the rolling bearing for a compressor pulley. The offset amount &dgr;, that is the axial distance between the center &agr; of the radial load applied to the follower pulley 4 from the endless belt 11, and the center &bgr; of the radial ball bearing 14 is 40% or less of the diameter of the pitch circle. In addition, the radial clearance of the radial ball bearing 14 is 0.2% or less of the diameter of the pitch circle. With this construction, the durability of the rolling bearing to support the follower pulley 4 is secured while made compact.

Abstract: An electric drive unit for windshield wipers of a motor vehicle, including a drive motor having an armature accommodated in a substantially cup-shaped pole housing, a substantially cup-shaped gearbox, secured on a face end to the pole housing, for receiving gear elements that convert the rotation of an armature shaft of the armature, supported on one end in the pole housing and on the other end in the gearbox. The armature shaft, adjacent to a bottom of the pole housing, is supported in a cylinder bearing mounted with a press-fit, whose outer diameter is greater than or equal to three times a length of the cylinder bearing.

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: An assembly method of a preload-adjustable rolling bearing unit comprising the steps of providing a shaft having a first inner raceway, an inner ring being press fitted onto the shaft and having a second inner raceway, such that a pitch of both raceways is set greater than a pitch required to give a predetermined preload, providing an outer ring having outer raceways, providing a plurality of balls to be fitted between the outer raceways of the outer ring, and the first and second inner raceways, positioning the balls equidistant apart in the circumferential direction, and vibrating the rolling bearing unit by means of piezo electric elements while moving the inner ring in the axial direction, measuring the resonant frequency of the rolling bearing unit with a vibration sensor to control the preload whereby the inner ring is pressed onto a shaft while vibrating with only a small amount of energy without scratching the raceway and rolling surfaces.

Abstract: A tapered roller bearing comprises: an outer race 12 having a raceway surface 21; an inner race 11 having a raceway surface 20; and a plurality of rolling elements 15 located between the raceway surfaces and formed by third generatrices having a fixed radius of curvature R3 such that the rolling contact surface is convex in the axial direction; and where the center section 20a, 21a of the raceway surfaces 20, 21 is formed by first generatrices having a fixed radius of curvature R1 in an axially concave-shape, and the opposite ends 20b, 21b in the axial direction adjacent to the center section 20a, 21a are formed by second generatrices having a fixed radius of curvature R2 such that they separate from the rolling contact surface of the rolling element 15; and where the radius of curvature R3 of the third generatrices surface satisfies Equation [1] below. R3=s×R1 wherein 0.65≦s≦0.95  Eq. [1].

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: The frequencies generated based on the undulations existing on the inner and outer ring raceways 8, 10 and on the rolling surface of the balls 11, 11 are out of coincidence with the rotational frequency itself of the rotation member supported by the rolling bearing, and with a frequency component which is a multiple of the rotational frequency, or kinds of frequencies generated due to the undulations are out of coincidence with each other in the natural frequency domain of a rotation system which is a rotation supporting portion having the rolling bearing incorporated therein, whereby without using a special grease, the self-excited frequency of the rolling bodies hardly grows to abnormal vibration, and a rolling bearing having sufficient durability and causing no abnormal vibration and noise even if used at low temperature is realized.

Abstract: The present invention provides a roller bearing in which a plurality of rollers is interposed between an inner ring member and an outer ring member, and a flange having a guide surface for guiding an end surface of the roller in a sliding contact manner is provided at an end portion of at least one of the inner ring member and outer ring member in an axial direction. Three-dimensional surface roughness of the end surface of the roller is defined to a value which satisfies conditional expressions of Sa≦0.1 &mgr;m and 0.15 &mgr;m≦Svk≦0.30 &mgr;m, where Sa is arithmetical average roughness based on rough curve and Svk is reduced valley depth based on the rough curve.

Abstract: The frequencies generated based on the undulations existing on the inner and outer ring raceways 8, 10 and on the rolling surface of the balls 11, 11 are out of coincidence with the rotational frequency itself of the rotation member supported by the rolling bearing, and with a frequency component which is a multiple of the rotational frequency, or kinds of frequencies generated due to the undulations are out of coincidence with each other in the natural frequency domain of a rotation system which is a rotation supporting portion having the rolling bearing incorporated therein, whereby without using a special grease, the self-excited frequency of the rolling bodies hardly grows to abnormal vibration, and a rolling bearing having sufficient durability and causing no abnormal vibration and noise even if used at low temperature is realized.

Abstract: An anti-friction bearing device comprising an outer ring (11) provided with an outer surface and a bore on which a toroidal bearing inner race (14) is formed, an inner ring(15) which is provided with a bore and a cylindrical outer surface on which a toroidal bearing outer race (18) is formed, a row of balls (19) which are disposed between the two bearing races, and a cage which can maintain a regular circumferential spacing between the balls. The ratio between the radial thickness of the outer ring, when taken between the bottom of the bearing inner race and the outer surface of the outer ring and the diameter of the balls ranges from 0.4 to 0.7. The ratio between the radial thickness of the outer ring, when taken between the bottom of the bearing inner race and the radial thickness of the inner ring when taken between the bottom of the outer bearing race and the bore of the inner ring ranges from 1.1 to 1.6.

Abstract: A motor comprises a rotor, a stator, and a shaft wherein one of the stator and the rotor is provided with a housing, a rolling bearing is provided between the housing and the shaft and having an inner race and outer race, the inner race is fixed to the shaft through adhesion between the outer peripheral surface of the shaft and the inner peripheral surface of the inner race, the outer race is fixed to the housing through press-fitting, and the outer peripheral surface of the shaft is formed with knurled grooves, where the number (P) of the knurled grooves in the circumferential direction and the number (Z) of the rolling members in the rolling bearing are in the relations of P≢n Z and P≢nZ±1 where n is a positive integer.

Abstract: The large-end-face roughness &sgr;1 of the tapered roller is set to be not less than 0.04 &mgr;mRa, consequently the assembling torque becomes generally constant and smaller in fluctuation over a range that the cone-back rib face roughness &sgr;2 is 0.03-0.23 &mgr;mRa. Also, the composite roughness &sgr;=(&sgr;12+&sgr;22)½ is set to be not more than 0.17 &mgr;mRa, consequently the preload retention rate on the regression curve can be made 90%. Further, the radius of curvature ratio R1/R2 resulting from dividing the convex radius of curvature R1 of the large end face of the tapered roller by the concave radius of curvature R2 of the cone-back rib face of the inner ring is set to be not more than 0.35, consequently the rotating torque becomes smaller in variation and also smaller in fluctuations over a range that the composite roughness &sgr; is 0.05-0.22 &mgr;mRa.

Abstract: A retainer for a roller bearing includes a pair of annular portions and a plurality of columns 23 provided between the annular portions. A plurality of pockets are defined by the annular portion and the column each for receiving a roller. An indented relief is provided on the corners of the plurality of pockets and the circumferential average width d (mm) of the column at the area where the indented relief is provided, the axial thickness t (mm) of the annular portion at the area where the indented relief is provided, the radius r (mm) of curvature of the indented relief, the average diameter Da (mm) of the roller and the pitch circle diameter dm (mm) of the bearing satisfy a relationship: 0.07×dm+20≦(2/d+4/t+1/r)×Da≦0.07×dm+50.

Abstract: A deep groove ball bearing has an inner ring, an outer ring and a plurality of balls located between the inner ring and the outer ring. A profile deformation quantity of a raceway groove of the inner ring and a profile deformation quantity of the outer ring are limited to values at which the maximum surface pressure values of them are each 1.6 GPa or smaller.

Abstract: An antifriction bearing includes a plurality of rolling elements each having a lateral surface possessing a conical shape, with the rolling elements being positioned between a conical raceway and a cylindrical raceway to roll along the conical raceway and the cylindrical raceway. The lateral surface of each rolling element forms an angle with a center axis of the rolling element that is 3° at maximum, and the lateral surface of each rolling element has a convex curvature that is superimposed on the conical shape. The bearing can also include a first bearing ring having a running surface constituting one of the conical and cylindrical raceways. An antifriction bearing arrangement incorporating such an antifriction bearing is also provided with a stop element having a stop face contacting the end face of each of the rolling elements.

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: The radius of curvature r1, r2 of the cross-sectional shape of an inner ring raceway lid is made smaller at a central portion 19 and larger at end portions 20. A contact ellipse at the end portions is made small by increasing the radius of curvature r2 of the end portions 20 to thereby secure an allowable moment load. In contrast with this, an angular gap is reduced by reducing the radius of curvature r1 of the central portion 19.

Abstract: A ball bearing comprising an inner ring having an outer peripheral surface formed with an inner ring raceway thereon, an outer ring having an inner peripheral surface formed with an outer ring raceway thereon, a cage made of synthetic resin and rotatably disposed relative to the inner ring and outer ring and having a plurality of pockets formed therein, and a plurality of balls held in the pockets, respectively, to be rotatably disposed between the inner ring raceway and outer ring raceway, wherein in the state before the cage is disposed between the inner ring and the outer ring, and where the balls held in the pockets are displaced toward the radially inside of the cage until the rolling contact surface of the balls comes in contact with the inner surface of the respective pockets to produce a circumscribed circle with a diameter with respect to the balls, the diameter of the circumscribed circle is smaller than the inner diameter of the outer ring raceway by an amount in the range 10 &mgr;m to 60 &mgr;m.

Abstract: A tapered roller bearing comprises inner and outer and outer rings having raceways, a large flange surface and a small flange surface, tapered rollers between the raceways and each having large and small end faces at the ends, and a retainer for the tapered rollers. The average roughness of the large end faces and the large flange surface is 0.14 &mgr;m Ra or less. The radius of curvature of the large end faces is 75 to 85% of the roller reference radius, and the central angle of the contact positions between the tapered rollers and the large flange surface is {fraction (1/15)} to {fraction (1/10)} of the roller angle. The center of the contact surface between the tapered rollers and the raceways is offset toward the large end faces from the center of the rolling surfaces of the tapered rollers by 10% or less of the effective length of the tapered rollers.

Abstract: The arrangement is such that the ratio of the diameter of balls 3 in the ultrathin-walled ball bearing to the pitch circle diameter PCD is not more than 0.03, and that the balls 3 are arranged in a single row and in two-point contact with the raceway surfaces 1a and 2a of the outer and inner members 1 and 2. The inner member 2 is composed of first and second raceway rim members 21 and 22 opposed to each other with an axial clearance S defined therebetween, and the internal clearances of the bearing are made negative by adjusting the width of the axial clearance S.

Abstract: A cylindrical roller bearing wherein the end surface of the rollers comes in contact with the guiding surface of the rib of the inner race with a contact ellipse therebetween, and at least one of the end surface and the guiding surface has a curved, convex surface, and provided that a second principal curvature plane passes through the center axis of the inner race and the center of the contact ellipse, that a first principal curvature plane perpendicularly crosses both the second principal curvature plane and the contact ellipse and extends through the center of the contact ellipse, that the cross sections of the end surface appearing in the first and second principal curvature planes have the principal radii (Rr2 and Rr1) of curvature, respectively, and that the cross sections of the guiding surface appearing in the first and second principal curvature planes have the proximal radii (Rf2 and Rf1) of curvature, respectively, the relationship between these principal radii of curvature is such that (1/Rf1)&min

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 tapered roller bearing that is well-suited for supporting a pinion in an automotive differential has a cone and a cup provided with opposed raceways that are crowned. The cone also has a thrust rib provided with a rib face at the large end of its raceway. In addition, the bearing has tapered rollers, each having a tapered side face that is crowned and a large end that is spherical. The rollers contact the raceways along their crowned side faces and the rib face along their spherical end faces. The roller length to large end diameter is less than 1.5. The crowning on the raceway, together with the crowning of the roller side face provide total end relief ranging between 700 &mgr;in. and 1500 &mgr;in. per inch. The centers of contact between the side faces and raceways are offset toward the rib face. The height of the rib face amounts to 30%-45% of the diameter of the large ends of the rollers. The radius of the spherical large end face for a roller exceeds 90% of the roller apex length.

Abstract: A tapered roller bearing and an automotive gear shaft support device can ensure a long endurance life even in the state in which debris is mixed. On the surfaces of an outer ring, inner ring, and tapered rollers formed from carburized bearing steel having an oxygen content of 9 ppm or less, carbo-nitrided layers having a carbon content of 0.80 wt % or over, a Rockwell hardness HRC of 58 or over, and a residual austenite content of 25-35 vol % are formed to increase mechanical properties and fatigue characteristics of the parts and to stably maintain the carbo-nitrided layers on the surfaces of the parts to a quality having suitable toughness, thereby markedly improving the endurance life of the tapered roller bearing in a state in which debris is mixed.

Abstract: A ball bearing in which the heat value in an inner ring is decreased and the heat value in an outer ring is brought closer to the heat value in the inner ring by making the radius of curvature for the inner ring groove larger, and defining the radius of curvature for the outer ring groove as 50.5% to 53.0% of the ball diameter. The arrangement of the present invention suppresses the heat value in the entire ball bearing and extends the bearing life at a reduced cost without using a large flow rate lubrication method or a preloading method such as constant preloading. In addition, a decrease in heat generation, seizing resistance and wear resistance can be attained further by optimizing a relation between the raceway groove and the ball diameter, by optimizing the number of balls, by controlling the ingredient composition for the material of the bearing ring, and by forming a hard deposition film on the surface of the raceway groove.

Abstract: An anti-frictional bearing which is reduced in its asynchronous rotational run out so that the cumbersome analyzing operation of the raceway surface and selecting operation of inner and/or outer races are not required. The bearing will contribute for the high packaging density and high speed operation of the hard disk device. An anti-frictional bearing including an inner raceway is formed on an outer peripheral surface of an inner race 1, an outer raceway 2a formed on an inner peripheral surface of an outer race 2, and a plurality of rotating bodies 3 interposed between the raceways and retained by retainers 4 in a predetermined distance with each other, wherein an out of roundness of a raceway surface 1a, 2a of at least one of said inner and outer races 1, 2 is equal to or less than 0.05 &mgr;m.

Abstract: In the ball bearing, the ratio of the radius of curvature of an inner race raceway 4 to the outside diameter of balls 8, 8 is set in the range of 0.51 to 0.54. Also, the ratio of the radius of curvature of an outer race raceway 6 to the outside diameter of balls 8, 8 is set in the range of 0.54 to 0.56. Further, an interior geometric clearance c is set at 13 &mgr;m or less. Thanks to these specifications, the balls 8, 8 can be prevented from running up onto the edge of the outer race raceway 6.

Abstract: An ultrathin walled rolling bearing in which the noise level is reduced and thus the sound characteristics are improved is provided. The rolling bearing is composed of an outer member having in its inner periphery a raceway surface, an inner member having in its outer periphery a raceway surface, a plurality of rolling elements interposed between the raceway surfaces of the outer and inner members, and a cage for circumferentially equi-spacing the rolling elements. In this bearing, the ratio of the diameter DB of the rolling element to the pitch circle diameter PCD of the bearing is equal to or less than 0.03. In addition, the ratio L/M falls within a range of 0.8 to 0.95 in which L is the radial thickness of the cage and M is the radius difference between the inner peripheral surface of the outer member and the outer peripheral surface of the inner member.

Abstract: An amount of undulation by which the inner surface 11 of a large-diameter-side flange portion 8 formed in an inner ring 5 is undulated is defined as an axial deflection &dgr;. And, the composite roughness of a contact portion between the inner surface 11 and the head portion 10 of a tapered roller 6 is expressed as &sgr;. A tapered roller bearing 1 is structured in such a manner that &dgr;≦8 &mgr;m and &sgr;≦0.22 &mgr;mRMS, or, &dgr;≦12 &mgr;m and &sgr;≦0.18 &mgr;, or, &dgr;≦16 &mgr;m and &sgr;≦0.13 &mgr;mRMS can be satisfied.

Abstract: A deep groove ball bearing has an inner ring, an outer ring and a plurality of balls located between the inner ring and the outer ring. A profile deformation quantity of a raceway groove of the inner ring and a profile deformation quantity of the outer ring are limited to values at which the maximum surface pressure values of them are each 1.6 GPa or smaller.

Abstract: A tapered roller bearing and an automotive gear shaft support device can ensure a long endurance life even in the state in which debris is mixed. On the surfaces of an outer ring, inner ring, and tapered rollers formed from carburized bearing steel having an oxygen content of 9 ppm or less, carbo-nitrided layers having a carbon content of 0.80 wt % or over, a Rockwell hardness HRC of 58 or over, and a residual austenite content of 25-35 vol % are formed to increase mechanical properties and fatigue characteristics of the parts and to stably maintain the carbo-nitrided layers on the surfaces of the parts to a quality having suitable toughness, thereby markedly improving the endurance life of the tapered roller bearing in a state in which debris is mixed.

Abstract: In the ball bearing, the ratio of the radius of curvature of an inner race raceway 4 to the outside diameter of balls 8, 8 is set in the range of 0.51 to 0.54. Also, the ratio of the radius of curvature of an outer race raceway 6 to the outside diameter of balls 8, 8 is set in the range of 0.54 to 0.56. Further, an interior geometric clearance c is set at 13 &mgr;m or less. Thanks to these specifications, the balls 8, 8 can be prevented from running up onto the edge of the outer race raceway 6.

Abstract: A dynamic pressure bearing apparatus comprises a rotary shaft, a sintered oil retaining bearing rotatably supporting the rotary shaft, the sintered oil retaining bearing having an interior surface defining an internal surface configuration for generating dynamic pressure to thereby form a dynamic pressure bearing between the rotary shaft and the sintered oil retaining bearing. The internal surface of the sintered oil retaining bearing comprises in a peripheral direction thereof, a minimum-gap section, a large-gap section and a separation groove section. The minimum-gap section has the minimum gap between the rotary shaft and the internal surface of the sintered oil retaining bearing.

Abstract: A retainerless angular contact antifriction bearing apparatus including an inner race member having a spheroidal inner race surface, an outer race member including a pair of convex outer race surfaces opposing the inner race surface, and a plurality of rollers arranged in axially oppositely inclined rows. Each roller includes a concave longitudinal profile having a radius of curvature greater than the radius of curvature of each of the spheroidal inner race surface and the associated convex outer race surface. The radial internal clearance between the roller and the race surfaces is no more than 0.002 inches.

Abstract: When a crowning is subjected to a roller or on a rolling surface using a combination of two arcs, a crowning profile is specified in such a manner that each crowning quantity at two points where distances x in a bus extending direction from the center line of the roller are respectively situated at positions of 0.425 and 0.5 times an effective contact length Le, are respectively present between the value of a well-known logarithmic crowning when a bearing load P is 0.4 times a basic load rating C and the value of the logarithmic crowning when the bearing load P is 0.6 times the basic load rating C.

Abstract: An amount of undulation by which the inner surface 11 of a large-diameter-side flange portion 8 formed in an inner ring 5 is undulated is defined as an axial deflection 8. And, the composite roughness of a contact portion between the inner surface 11 and the head portion 10 of a tapered roller 6 is expressed as &sgr;. A tapered roller bearing 1 is structured in such a manner that &dgr;≦8 &mgr;m and &sgr;≦0.22 &mgr;mRMS, or, &dgr;≦12 &mgr;m and &sgr;≦0.18 &mgr;, or, &dgr;≦16 &mgr;m and &sgr;≦0.13 &mgr;mRMS can be satisfied.

Abstract: In the roller bearing, between an outer ring (1) and an inner ring (2), there are interposed a plurality of tapered rollers (3) in a freely rollable manner. A flange portion (4) is formed in the side portion of the inner ring (2). The undercut allowance ratios of a contact ellipse formed due to mutual contact between the flange portion (4) and the end face of the roller (3) is set in the range of −0.6≦(h−b−c)/b≦2, where a grinding undercut dimension on the flange portion (4) is expressed as c, a contact point height between the flange portion (4) and the end face of the roller (3) is expressed as h, and the minor radius of a contact ellipse formed due to contact between the flange portion (4) and the end face of the roller (3) is expressed as b.

Abstract: An anti-frictional bearing which is reduced in its asynchronous rotational run out so that the cumbersome analyzing operation of the raceway surface and selecting operation of inner and/or outer races are not required. The bearing will contribute for the high packaging density and high speed operation of the hard disk device. An anti-frictional bearing including an inner race way 1a formed on an outer peripheral surface of an inner race 1, an outer raceway 2a formed on an inner peripheral surface of an outer race 2, and a plurality of rotating bodies 3 interposed between the raceways and retained by retainers 4 in a predetermined distance with each other, wherein an out of roundness of a raceway surface 1a, 2a of at least one of said inner and outer races 1, 2 is equal to or less than 0.05 &mgr;m.

Abstract: A tapered roller bearing and an automotive gear shaft support device which can ensure a long endurance life even in the state in which debris is mixed. On the surfaces of an outer ring, inner ring, and tapered rollers formed from carburized bearing steel having an oxygen content of 9 ppm or less, carbo-nitrided layers having a carbon content of 0.80 wt % or over, a Rockwell hardness HRC of 58 or over, and a residual austenite content of 25-35 vol % are formed to increase mechanical properties and fatigue characteristics of the parts and to stably maintain the carbo-nitrided layers on the surfaces of the parts to a quality having suitable toughness, thereby markedly improving the endurance life of the tapered roller bearing in a state in which debris mixed.

Abstract: A bearing is provided which can be sufficiently processed by a usual NC grinding machine, and attain a life period that is substantially equal to that of a bearing having a theoretical crowning shape which is derived from the elastic contact theory, even when the bearing is used in a portion to which a heavy load or a high torque load is applied. As means for realizing such a bearing, a generating line of a rolling surface of a roller or a raceway surface of an inner or outer race is divided into a plurality of zones, and the shape of the generating line is approximated to a special curve shape which is theoretically derived, by a plurality of circular arcs which are contacted with each other on the border line between the corresponding zones. Therefore, it is possible to obtain a roller bearing which can be practically used, and which can attain a life period that is substantially equal to that of a bearing having an ideal crowning shape.

Abstract: A tapered roller bearing and an automotive gear shaft support device can ensure a long endurance life even in the state in which debris is mixed. On the surfaces of an outer ring, inner ring, and tapered rollers formed from carburized bearing steel having an oxygen content of 9 ppm or less, carbo-nitrided layers having a carbon content of 0.80 wt % or over, a Rockwell hardness HRC of 58 or over, and a residual austenite content of 25-35 vol % are formed to increase mechanical properties and fatigue characteristics of the parts and to stably maintain the carbo-nitrided layers on the surfaces of the parts to a quality having suitable toughness, thereby markedly improving the endurance life of the tapered roller bearing in a state in which debris is mixed.

Abstract: A roller bearing with roller elements constructed as rollers (4) or balls arranged between an inner race (3) and an outer race (5), and with a thick-walled outer ring (6) if provided. The inner surface of the outer ring forms the outer race (5) and the outer surface is provided for direct rolling on a cylindrical matching roller path, and has a crowned contour (7) curved in longitudinal section. In accordance with the invention, the spherical crowned contour (7) of the outer ring (6) is formed from several arcs that pass smooth into one another whereby the radius of curvature of a central arc and the radius of curvature of an outer arc have in a ratio from 2 to 1 up to 5 to 1 in relation to one another.

Abstract: There is provided a roller bearing in which contact stress between a roller and a raceway is uniformized by optimizing a configuration of a clearance between the roller and the raceway. A configuration of an outer circumferential surface (8) of a tapered roller (6) of a tapered roller bearing (1) is defined so that a clearance of Y(x)=kYp(x), which results from multiplying an equation Yp(x) for uniformizing contact stress between infinite-width plate and tapered roller by a positive number k=1.5-10, is formed between the raceway surface (4, 5) and the outer circumferential surface (8) of the tapered roller (6). The tapered roller (6) relaxes concentration of contact stresses, improving the durability.

Abstract: A tapered roller bearing has inner and outer races and tapered rollers organized in at least two rows, with the rollers of the one row being generally aligned with the rollers in the other row. The large ends of the rollers are presented toward each other so that the forces which urge the rollers of either row up their tapered raceways are resisted by the rollers of the other row. The end faces of the aligned rollers in the two rows contact each other or else contact rollers of an intervening row. The geometry of the rollers and the raceways along which they roll are such that, when one race rotates relative to the other race, pure rolling contact exists between the side faces of the rollers and the raceways and pure rolling contact also exists at the end faces of the rollers. Moreover, the lines of contact for the aligned rollers of any set are synchronized and the rollers are stable.

Abstract: In the double row ball bearing, a plurality of balls are incorporated into a space between a first inner race raceway of an inner race and a first outer race raceway of an outer race, a plurality of balls are incorporated into a space between a second inner race raceway of the inner race and a second outer race raceway of the outer race, there is formed a counterbore portion at least in the outer race raceway of a pair of one-row side inner and outer race raceways, and the balls are incorporated in a maximum manner into a space between the pair of inner and outer race raceways which are so arranged as to include the outer race with the counterbore portion formed therein, to thereby make it possible to provide a double row ball bearing in which the rated load of one-row side raceway thereof can be selected up to its maximum with respect to the outside diameter dimension of an outer race thereof, and an excellent fatigue life can be attained.

Abstract: A roller bearing with symmetric barrel shaped rollers comprising an inner race (13), an outer race (14) and rollers (11), each of which rollers have at least one rounded end, and being of the bearing type where rollers and race tracks have longitudinal section profiles with substantially the same radius of curvature, whereby the rollers during normal operating conditions are axially moveable between the race tracks without hindrance from axial confinements at the race tracks for allowing relative misalignment and axial displaceability of the race tracks, wherein the end drop zone has a length (d1) which is lower than 5% of the length (1a) of the roller, and which commences where the bend of the curvature of the roller in axial direction exceeds the normal curvature of the roller by 0.1°, and where the end drop of the roller is otherwise determined by the following relations, r/1a≧0.35 for &ggr; values up to 0.7°, and r/1a is ≧0.2 for &ggr; values between 0.7° and 1.4°.