Ntn Corporation

Takashi Ueno

Yasuhiro Kanbori

Chikara Ohki

Takashi Tsujimoto

Tomoki Matsushita

Tatsuya Omoto

Daisuke Sato

Yasutaka Kusumi

Kyouhei Kageyama

Shougo Shimizu

A tapered roller bearing includes an outer ring, an inner ring, a plurality of tapered rollers, and a holder. A nitrogen concentration in a surface layer portion under a contact surface is 0.3 mass % or more. The holder includes a small annular portion, a large annular portion, and a plurality of column portions. A pocket has a trapezoidal shape in which a portion housing a small diameter side of the tapered roller is located on a reduced width side while a portion housing a large diameter side of the tapered roller is located on an increased width side. Each of the column portions on the reduced width side of the pocket is provided with a cutout.

Tapered roller bearing

A retainer includes two annular retaining plates combined with each other, and each having semispherical bulging portions arranged at predetermined intervals along a circumferential direction of the retainer. The semispherical bulging portions, which face each other, form a pocket having a ring-like shape, for retaining a ball. The pocket includes a ball non-contact portion formed in a ball facing surface of the pocket at a center portion in a pocket axial direction, the ball non-contact portion being defined by a recess extending in a pocket circumferential direction. The following relationship is set: A/(B+C)=0.70 to 0.90, where 'A' represents a pocket circumferential length of the ball non-contact portion, 'B' represents a diameter of the ball, and &#x201c;C&#x201d; represents a gap formed between the ball and the ball facing surface of the pocket.

Retainer and ball bearing

An outer ring, an inner ring, and a ball, each of which is a bearing part, are made of a quench-hardened steel containing not less than 0.90 mass % and not more than 1.05 mass % of carbon, not less than 0.15 mass % and not more than 0.35 mass % of silicon, not less than 0.01 mass % and not more than 0.50 mass % of manganese, and not less than 1.30 mass % and not more than 1.65 mass % of chromium with the rest consisting of an impurity. A contact surface thereof with another part has a nitrogen concentration of not less than 0.25 mass %. A remaining austenite amount in the contact surface is not less than 6 volume % and not more than 12 volume %.

Bearing part, rolling bearing, and methods of manufacturing them

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 () having a first axial side, and a cylindrical second split retainer member () having a second axial side coupled to the first axial side of the first split retainer member (). Circumferentially spaced apart first and second cutouts (and) are formed in the first axial side of the first split retainer member () and the second axial side of the second split retainer member (), respectively, which define respective pockets for receiving balls with the split retainers (and) coupled together. A coupling arrangement (X) is provided between the first and second split retainer members (and) which is adapted to engage the split retainer members (and) when the split retainer members (and) are coupled together, thereby keeping the split retainer members (and) axially inseparable from each other. With the retainer mounted in a deep groove ball bearing, when the outer race () and the inner race () rotate relative to each other, since the first and second split retainer members (and) rotate at different peripheral speeds due to a difference in diameter therebetween, pumping action is produced in the bearing, which causes a forced flow of lubricating oil in the bearing.

Retainer made of synthetic resin for use in a deep groove ball bearing; deep groove ball bearing; and gear support device

A retainer for a tapered roller includes a first side having a first radius and a second side having a second radius, wherein the first radius is smaller than the second radius, a first ring portion at the first side of the retainer, a second ring portion at the second side of the retainer, and a plurality of brace portions arranged between the first ring portion and the second ring portion. The retainer is made of a resin material and is configured to retain tapered rollers in pockets formed between the brace portions. A hook portion is formed at the second side of the retainer, and is engaged with an inner race on a second side having a larger radius than a first side thereof. An outer diameter of each pocket on the first side of the retainer is larger than an inner diameter of the hook portion.

Retainer for tapered roller bearing, method for manufacturing retainer, and tapered roller bearing

A tapered roller bearing includes a retainer with a protrusion that is axially brought into engagement with a flange of the inner race. The inner race has a flange for guiding the tapered rollers only at the large-diameter end of the raceway. The retainer has on the large-diameter side thereof a protrusion radially inwardly extending and axially engaging the flange of the inner race. The flange of the inner race is formed with a circumferentially continuous cutout groove having a smoothly curved concave surface through which the radially outer surface and the outer end surface of the flange are connected to each other. The protrusion of the retainer has its inner side at its radially inner end portion in engagement with the cutout groove, allowing size reduction and load bearing capacity increase for the tapered roller bearing, while preventing stress concentration on the flange of the inner race.

A tapered roller bearing includes an outer ring, an inner ring, a tapered roller interposed between the outer ring and the inner ring, and a cage holding the tapered roller. The tapered roller bearing is for being used in an idler portion of an automobile transmission that switches between an idle state in which the outer ring rotates freely in relation to the inner ring and a shift state in which the outer ring rotates synchronously with the inner ring. In one embodiment, the tapered roller bearing has a ratio of roller dynamic load rating Cr to static load rating Cor of Cor/Cr&#x2267;1.4. In an alternative embodiment, MoSprocessing is performed on a surface of the tapered roller and the tapered roller bearing has a ratio of roller dynamic load rating Cr to static load rating Cor of Cor/Cr&#x2267;1.3.

A taper roller bearing includes an inner race, an outer race, taper rollers arranged so as to be rollable between the inner and outer races, and a retainer for retaining the taper rollers, in which a flange portion is provided only on the radially larger side of the inner race. The retainer includes a radially-larger-side annular portion including a hook portion. The hook portion effects hooking so that the flange portion of the inner race is maintained in an assembled state. In a neutral state, the hook portion is kept out of contact with the flange portion. A guide surface portion for guiding the inner race to be incorporated is provided on a radially inner end portion of an outer surface of the hook portion.

Taper roller bearing

In a tapered roller bearing, the roller coefficient &#x3b3; is greater than 0.94. At least one member of an inner ring, an outer ring, and the tapered rollers includes a nitrogen-rich layer, and the grain size number of austenite crystal grains in the nitrogen-rich layer is greater than 10. A cage of the tapered roller bearing includes a small annular portion continuous on a small end face side of the tapered rollers, a large annular portion continuous on a large end face side of the tapered rollers, and a plurality of bars that connect the small and large annular portions. The cage has trapezoidal pockets between adjacent ones of the bars. Each of the bars has cut-away portions on the narrow side of the pockets.

A tapered roller bearing includes a retainer formed with a plurality of trapezoidal pockets. Each pocket includes cutouts formed in the crossbars defining each pocket near the narrow end thereof. A tapered roller is received in each pocket with its small-diameter end facing the narrow end of the pocket. Lubricating oil flowing into the bearing space defined radially inwardly of the retainer can quickly flows through the cutouts into the bearing space defined radially outwardly of the retainer at the narrow end of each pocket. Thus, it is possible to reduce the amount of lubricating oil flowing along the raceway of the inner ring to the large-diameter flange, and thus reduce the amount of lubricating oil remaining in the bearing, thereby reducing the torque loss due to rotational resistance of the bearing resulting from lubricating oil remaining in the bearing.

Growing community of inventors

Iwata, Japan

Takashi Ueno