Tapered roller bearing

Abstract

A tapered roller bearing ( 1 ) is includes an outer ring ( 2 ) having an outer ring raceway surface ( 2 a ) on the inner peripheral surface thereof, an inner ring ( 3 ) having an inner ring raceway surface ( 3 a ) on the outer peripheral surface thereof, and a plurality of tapered rollers ( 4 ) arranged in a rollable manner between the outer ring raceway surface ( 2 a ) and the inner ring raceway surface ( 3 a ). A large flange ( 3 b ) is formed on an end portion of the inner ring ( 3 ) on a large-diameter side of the inner ring, and the inner ring raceway surface ( 3 a ) continuously extends to the end face ( 3 c ) of the inner ring ( 3 ) on a small-diameter side of the inner ring. The contact angle (α) is 35° to 55°. In this manner, the tapered roller bearing having high moment rigidity and long life can be provided.

1 . A tapered roller bearing comprising:
 an outer ring having an outer ring raceway surface on an inner peripheral surface thereof;   an inner ring having an inner ring raceway surface on an outer peripheral surface thereof; and   a plurality of tapered rollers arranged in a rollable manner between the outer ring raceway surface and the inner ring raceway surface,   wherein the inner ring comprises a large-diameter side and a small-diameter side, a flange being formed only on an end portion of the inner ring on the large-diameter side of the inner ring, and   wherein a contact angle α of the tapered roller bearing is 35° to 55°.   
     
     
         2 . The tapered roller bearing according to  claim 1 ,
 wherein the inner ring raceway surface continuously extends to an end face of the inner ring on the small-diameter side of the inner ring.   
     
     
         3 . The tapered roller bearing according to  claim 1 , wherein a ratio between a height (D 1 −d)/2 of the inner ring on the flange side and a radial cross-section thickness H of the tapered roller bearing is set such that 0.7<(D 1 −d)/2H<0.9, wherein d is an inner diameter of the tapered roller bearing and D 1  is an outer diameter of the inner ring. 
     
     
         4 . The tapered roller bearing according to  claim 1 , wherein a ratio between a roller length Lw and a width B of the inner ring is set such that 0.8<Lw/B<1.2. 
     
     
         5 . The tapered roller bearing according to  claim 1 , wherein a ratio between a radial cross-section thickness H of the tapered roller bearing and an inner diameter d of the tapered roller bearing is set such that 0.05<H/d<0.15. 
     
     
         6 . The tapered roller bearing according to  claim 1 , wherein a ratio between a diameter Dw 1  of each tapered roller on a large-diameter side of each tapered roller and a radial cross-section thickness H of the tapered roller bearing is set such that 0.3<Dw 1 /H<0.6. 
     
     
         7 . The tapered roller bearing according to  claim 1 , further comprising a resin cage, the cage comprising a large-diameter ring portion, a small-diameter ring portion, the large-diameter ring portion and the small-diameter ring portion being spaced from each other in an axial direction, and a plurality of pillar portions connecting the large-diameter ring portion and the small-diameter ring portion to each other, thereby forming a plurality of pockets to accommodate and to retain the plurality of tapered rollers,
 wherein at least one of an inner peripheral surface of the large-diameter ring portion and an outer peripheral surface of the small-diameter ring portion is formed with an annular notch such that a thickness of the ring portion is smaller than a thickness of each pillar portion.   
     
     
         8 . The tapered roller bearing according to  claim 7 , wherein the annular notch is formed on the inner peripheral surface of the large-diameter ring portion, and
 wherein the flange is arranged to extend into the annular notch.   
     
     
         9 . The tapered roller bearing according to  claim 1 , further comprising a resin cage, the cage comprising a large-diameter ring portion, a small-diameter ring portion, the large-diameter ring portion and the small-diameter ring portion being spaced from each other in an axial direction, and a plurality of pillar portions connecting the large-diameter ring portion and the small-diameter ring portion to each other, thereby forming a plurality of pockets to accommodate and to retain the plurality of tapered rollers,
 wherein the pillar portions are formed such that:   in at least a part of a radially inner side of each pocket, an overlap width is 0.1 mm to 0.7 mm so that an opening width of each pocket on the radially inner side is smaller than a diameter of each tapered roller on a large-diameter side of each tapered roller, and   in at least a part of a radially outer side of each pocket, an overlap width is 0.1 mm to 0.6 mm so that an opening width of each pocket on the radially outer side is smaller than a diameter of each tapered roller on a small-diameter side of each tapered roller.   
     
     
         10 . The tapered roller bearing according to  claim 1 , further comprising a resin cage, the cage comprising a large-diameter ring portion, a small-diameter ring portion, the large-diameter ring portion and the small-diameter ring portion being spaced from each other in an axial direction, and a plurality of pillar portions connecting the large-diameter ring portion and the small-diameter ring portion to each other, thereby forming a plurality of pockets to accommodate and to retain the plurality of tapered rollers,
 wherein an inclination angle of the cage is equal to or greater than 32°  30 ′ but smaller than 55°.   
     
     
         11 . The tapered roller bearing according  claim 1 , wherein the flange has a recessed portion at a location facing the cage. 
     
     
         12 . The tapered roller bearing according to  claim 11 , wherein the recessed portion is formed between a flange surface of the flange that contacts a larger end face of each tapered roller, and a radially outer surface of the flange having a diameter larger than a diameter of the flange surface of the flange at a radially outermost point on the flange surface, and is formed by a curved surface, a stepped surface, or a combination of the curved surface and the stepped surface. 
     
     
         13 . The tapered roller bearing according to  claim 11 , wherein the recessed portion is formed axially inward of a virtual plane, the virtual plane being perpendicular to a rotation axis of the tapered roller bearing and including an edge line at which the recessed portion and the radially outer surface of the flange meet each other. 
     
     
         14 . The tapered roller bearing according to  claim 13 , wherein the generatrix shape of the recessed portion is formed by the single arc, a curvature radius r of which being r≧(D 1 −D 2 )/2, wherein D 1  is the diameter of the radially outer surface of the flange and D 2  is the diameter of the flange surface of the flange at the radially outermost point. 
     
     
         15 . The tapered roller bearing according to  claim 1 , wherein the contact angle α is 45°.