Ntn Corporation

Yasuhiro Kanbori

Takashi Tsujimoto

Takashi Ueno

Tomoki Matsushita

Yuuji Okamoto

Jiro Mochizuki

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.

Tapered roller bearing

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 tapered roller bearing is capable of suppressing the occurrence of fretting without shortening its fatigue life. The tapered roller bearing includes an outer race, an inner race, a plurality of taper rollers interposed between the outer race and the inner race, and a retainer for retaining the tapered rollers. The tapered roller bearing is used in an idler portion of an automobile transmission, which is interchanged between an idle state in which the outer race idles with respect to the inner race and a shift state in which the outer race and the inner race are rotated synchronously with each other. A ratio of &#x3b1;/&#x3b2;&#x2267;4.9 is established on a premise that an outer-race raceway surface angle is 2&#x3b1; and a roller angle is &#x3b2;.

A tapered roller bearing comprises an inner ring having a conical surface-like raceway surface in it outer periphery and formed with a cone back face rib and a cone front face rib on the opposite sides of the raceway, an outer ring having a conical surface-like raceway in its inner periphery, a plurality of tapered rollers interposed between the raceways of the inner and outer rings, and a cage for holding the tapered rollers in predetermined circumferential intervals, wherein the ratio R/Rof the radius of curvature R of the large end face () of the tapered roller () to the distance Rfrom the apex of cone of the tapered roller () to the cone back face rib surface () of the inner ring () is set at 0.75 to 0.87, and the end face deflection of the large end face () of the tapered roller () is 3 &#x3bc;m or less.

Growing community of inventors

Iwata, Japan

Yasuhiro Kanbori