Ntn Corporation

Michio Hori

Takashi Yamamoto

Kazumasa Seko

Yasuyuki Inoue

Chikara Ohki

Kazuhiro Yagita

Hideto Torisawa

Hiroshi Yuki

Tomoya Sakaguchi

Tatsuya Omoto

Eiichi Nakamizo

Masaki Nakanishi

Hideshi Nishiwaki

Naoya Hasegawa

Junichi Hattori

Kouichi Okugami

Yoshinori Muramatsu

Yasuyuki Tsuji

Weida Yan

Nurumu Kuwahara

Provided is a double-row self-aligning roller bearing including: an inner ring; an outer ring having a spherical raceway surface; and rollers arranged in two rows and interposed between the inner ring and the outer ring, wherein a ratio of a contact angle &#x3b8;in one row to a contact angle &#x3b8;in the other row falls within a range of 0.25&#x2264;&#x3b8;&#x2264;0.5, and a ratio of distance Bin a bearing width direction from an end face of the bearing on a side of the one of the rows to an intersection of two lines of action defining the contact angles of the two rows, relative to a distance Bin the bearing width direction from an end face of the bearing on a side of the other of the rows to the intersection falls within a range of 0.5&#x2264;B/B&#x2264;0.6.

Double-row self-aligning roller bearing

The double-row self-aligning roller bearing includes an outer ring having a spherical raceway surface, and each of rollers in two rows has an outer peripheral surface whose cross-sectional shape corresponds to the raceway surface of the outer ring. The rollers in the two rows have different lengths from each other, and the length of the longer rollers is equal to or greater than 36% of a bearing width. A ratio of a contact angle of the shorter rollers relative to a contact angle of the longer rollers is within a range of 1:4 to 1:2. The contact angle of the shorter rollers has a range of 3&#xb0; to 5&#xb0;, and the contact angle of the longer rollers has a range of 11&#xb0; to 14&#xb0;.

A double-row self-aligning roller bearing has rollers interposed, in two rows aligned in a bearing width direction, between an inner ring and an outer ring. The outer ring has a spherical raceway surface. Each of the rollers has an outer circumferential surface having a cross-sectional shape that matches the raceway surface of the outer ring. Either or both of shapes and contact angles of the rollers are different from each other. An attachment hole to which a protrusion prevention jig is attachable is provided in an end surface of at least either one of the inner ring and the outer ring. The protrusion prevention jig prevents protrusion of the end surface of the inner ring in the bearing width direction with respect to the end surface of the outer ring.

Double-row self-aligning roller bearing and protrusion prevention jig

A rolling bearing includes an inner ring, an outer ring, and rolling elements interposed between the inner ring and the outer ring. A surface layer portion, beneath a raceway surface (), of a base material of a raceway ring () which is the inner ring or the outer ring, is a wear-resistant layer () which has a higher hardness than a residual portion (), beneath the surface layer portion, of the base material, and includes a minute-recess-and-projection surface. An oxide film () is provided which has such a film thickness (t) as to fill recesses of the minute-recess-and-projection surface of the wear-resistant layer (), and includes recesses and projections existing along the minute-recess-and-projection surface, and the oxide film () coats the surface of the wear-resistant layer (). The oxide film () is made from a material more fragile than the wear-resistant layer () of the base material.

Rolling bearing, and abrasion resistance treatment method for bearing raceway surface

There is prepared a formed body constituted of steel and having an outer circumferential surface having an annular groove having a bottom surface to serve as a raceway surface of the bearing ring. In the step of forming a heated region, the formed body is induction heated to form a heated region including the bottom surface of the groove and heated to a temperature of at least an Apoint. In the cooling step, the whole of the heated region is simultaneously cooled to a temperature of not more than an Mpoint. The step of retaining the formed body in a state in which heating is stopped is performed after the step of forming a heated region before the step of cooling. In the step of retaining, dispersion in temperature in the heated region in the circumferential direction is suppressed to not more than 20&#xb0; C.

Method for producing bearing ring, double row tapered roller bearing, and method for producing double row tapered roller bearing

A double-row self-aligning roller bearing has rollers interposed, in two rows aligned in a bearing width direction, between an inner ring and an outer ring. The outer ring has a spherical raceway surface. Each of the rollers has an outer circumferential surface having a cross-sectional shape that matches the raceway surface of the outer ring. The rollers have lengths equal to each other and maximum diameters equal to each other, and have different distances from centers of the roller lengths to positions at which the maximum diameters are obtained.

A double-row self-aligning roller bearing, which is suitable for receiving an axial load and a radial load, and loads having different magnitudes acting on rollers in two rows, and achieves sufficient load capacity for the rollers that receive axial load within the constraint of dimensional standards, is provided. The double-row self-aligning roller bearing includes inner and outer rings; and rollers in two rows arranged in a bearing width direction interposed between the inner and outer rings and having lengths different from each other. The roller has an outer peripheral surface of a cross-sectional shape along a raceway surface of the outer ring having a spherical shape. Length of the longer rollers is equal to or greater than 39% of the bearing width. A ratio of contact angle of the shorter rollers and contact angle of the longer rollers is within a range of 1:4 to 1:2.

A double row tapered roller bearing includes: an outer ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and having an annular shape; and rollers. The inner ring has an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface. The rollers are tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and are also in contact with the outer ring. At outer circumferential surface of the inner ring, a region adjacent to the groove includes a hardened region extending from the inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region.

Double row tapered roller bearing, bearing ring, and method for producing double row tapered roller bearing

The method for calculating rotational torque between inner and outer rings of a four point contact ball bearing assembly includes an individual torque calculation step for calculating the rotational torque for each of rolling elements and a total sum calculation step for determining the rotational torque. In the individual torque calculation step, data on a contact condition representative of the extent of approximation to the two point contact state or four point contact state is used. For the contact condition data, the four point contact ratio C, which is the ratio of surface pressure of one of respective maximum contact pressures Pand Pbetween two partial raceways in an inner ring or outer ring, which one is higher than the other of the maximum contact pressures Pand P, relative to a surface pressure of the other of the maximum contact pressures, is used.

Torque calculation method, calculation device, and calculation program for four-point contact ball bearing

A slewing bearing assembly effective to suppress additional expenses such as a mold cost and to resolve the problem associated with insufficient strength brought about by voids and, also, a rotation section support apparatus for a wind powered turbine are provided. The slewing bearing assembly includes inner and outer rings having raceway grooves, and a plurality of balls interposed between the raceway grooves, and a spacer interposed between the neighboring balls. This slewing bearing assembly is a four point contact ball bearing, in which respective sectional shapes of the raceway grooves are so shaped as to represent shapes in which each balls contacts inner surfaces of the raceway grooves in the inner and outer rings at four points. The spacer is made of a resinous material having a melt viscosity within the range of 1000 to 2000 Pa&#xb7;s at a temperature of 270&#xb0; C.

Slewing bearing and rotating section support device for wind turbine

Tapered rollers are retained between outer and inner rings by a retainer to be circumferentially spaced apart from each other. The inner ring has a raceway on its outer surface and includes small and large-diameter flanges at the small- and large-diameter ends of the raceway, respectively. The retainer includes two annular portions and crossbars extending between the annular portions. Its radially inner surface is located radially inwardly of the pitch cone of the tapered rollers to increase the thickness of the crossbars and the axial thickness of the small-diameter annular portion. The conical surface defined by the outer surfaces of the crossbars has an inclination angle that is greater than the central angle of the bearing to increase the volume of the crossbars. The rigidity of the retainer is thus increased.

Tapered roller bearing

A transmission component is incorporated into a transmission in which an input shaft, an output shaft, or a gear is rotatably supported by a rolling bearing. The component has a nitriding layer at a surface layer and an austenite grain with a grain size number falling within a range exceeding 10. This provides a transmission component having an increased anti-crack strength, enhanced dimensional stability, and a long fatigue life. A method of manufacturing such a transmission component and a tapered roller bearing are also provided.

Transmission component, method of manufacturing the same, and tapered roller bearing

The object is to reduce the contact surface pressure between the balls and the retainer of a thrust ball bearing at slide contact positions, thereby suppressing the wear of the retainer. By increasing the depth of drawing of inner and outer portions embracing the balls received in pockets of the retainer, when the balls roll on the raceways of the outer ring and the inner ring, the balls and the retainer are adapted to slidably contact each other at three portions, i.e. the peripheral edge of each pocket, and the outer portion and the inner portion of the retainer. Thus, it is possible to reduce the contact surface pressure at the respective slide contact positions compared to the prior art. Thus, it is possible to suppress the wear of the retainer.

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Kuwana, Japan

Michio Hori