Ntn Corporation

Manabu Hoshino

Tohru Nakagawa

Wasaburo Suganuma

Teruaki Fujio

Masazumi Kobayashi

Minoru Ishijima

Shuji Mochinaga

Katsuhiro Suzuki

Kazuhiro Muramatsu

Tomoaki Kaneko

Hiroshi Teduka

Junichi Izumino

Hiroshi Tone

A driving-wheel bearing device includes an outer race having double-row outer raceway surfaces formed on an inner periphery thereof, a hub wheel and an inner race having a wheel attachment flange at one end thereof and double-row inner raceway surfaces on an outer periphery thereof, and double-row rolling elements interposed between the outer raceway surfaces of the outer race and the inner raceway surfaces of the hub wheel and the inner race, the hub wheel having a shaft hole into which a stem section extending from an outer joint member of a constant velocity universal joint is spline-fitted by being press-fitted, in which a plate having a molybdenum coating layer or a fluorine-resin coating layer formed thereon and having a plate thickness ranging from 0.5 mm to 2 mm is interposed between opposite surfaces of a shoulder portion of the outer joint member and an crimped portion of the hub wheel.

Bearing device for driving wheel

A fixed type constant velocity universal joint is capable of reducing the size and weight of a cage while keeping the strength of the cage, and is also capable of improving the high angle strength and the durability. An offset angle &#x3b8;of the cage, which is defined by lines that connect a center curvature of an inner spherical surface and a center curvature of an outer spherical surface of the cage and centers of torque transmission balls, and a line that connects the centers of the torque transmission balls and a joint center in a state where a joint operating angle is 0&#xb0;, is set in a range of 2.7&#xb0;&#x2266;&#x3b8;&#x3c;5.7&#xb0;.

Fixed type constant velocity universal joint

A fixed type constant velocity universal joint is capable of, without involving decreases in load capacity of an inner joint member (inner member) and in spherical area, increasing rigidity of a cage and stabilizing durability. The cage has four pockets including a pair of long pockets with large circumferential intervals and a pair of short pockets with small circumferential intervals. The pair of long pockets can be shifted by 180 degrees along a circumferential direction, and the pair of short pockets can be shifted by 180 degrees along the circumferential direction. The long pockets and the short pockets are arranged alternately to each other along the circumferential direction. Two balls are accommodated in each of the long pockets, while one ball is accommodated in each of the short pockets. A cutout portion is provided to an inner end portion of at least one of the track grooves of the inner member.

Internal dimensions for fixed-type constant velocity universal joints are defined to optimize the geometry of the components of the joints and to readily achieve a larger operating angle of the joints. In the joint, the track grooves of an outer ring and an inner ring are tapered by an angle not exceeding 12&#xb0;. The ratio (f/PCR) of the cage offset amount f to PCR is greater than 0 and smaller than or equal to 0.12. The ratio (Do/d) of the cage outer diameter (Do) to the ball diameter (d), the ratio (t/d) of the cage wall thickness (t) to the ball diameter (d), and the ratio (w/d) of the cage width (w) to the ball diameter (d) are such that 3.9&#x2266;Do/d&#x2266;4.1, 0.31&#x2266;t/d&#x2266;0.34, and 1.8&#x2266;w/d&#x2266;2.0, respectively. The end of the spherical outer surface of the cage adjacent to the open end is axially extended, and the end of the spherical inner surface of the cage adjacent to the open end is tapered so that the tapered surface has an increasing diameter toward the end of the spherical outer surface adjacent to the open end. Part of the spherical outer surface of the cage is cut on the open end side of pockets, and the outer diameter of the cage across the two opposing planer cut faces is smaller than the spigot diameter of the outer ring.

Fixed-type constant-velocity universal joint

A fixed constant velocity universal joint of a structure, which easily allows incorporation of an inner ring into a cage without impairing a function of the joint, is provided. The fixed constant velocity universal joint has an outer ring having in an inner spherical surface thereof a plurality of track grooves arranged at equal circumferential intervals and extending axially toward an open end, an inner ring having in an outer spherical surface thereof a plurality of axially extending track grooves paired with the track grooves of the outer ring and arranged at equal circumferential intervals, a plurality of balls interposed between the track grooves of the outer ring and the track grooves of the inner ring, for transmitting torque, and a cage interposed between the inner spherical surface of the outer ring and the outer spherical surface of the inner ring, for holding the balls, in which an outer ring open end side of the outer spherical surface of the inner ring is cut off, with a boundary portion between a cutoff portion thereby obtained and the outer spherical surface being rounded.

Fixed constant velocity universal joint

A fixed constant velocity universal joint is made compact, has little decrease in load capacity even when the fixed constant velocity universal joint is made compact and is at an operating angle, and has improved high angle strength and durability through lessening instances in which a ball runs over a track at a high angle. In the fixed constant velocity universal joint, a cage includes four pockets, the pockets including a pair of long pockets of which a circumferential direction spacing is wide and a pair of short pockets of which the circumferential direction spacing is narrow. The pair of long pockets are shifted by 180 degrees along a circumferential direction and the pair of short pockets are shifted by 180 degrees along the circumferential direction. As a result, the long pockets and the short pockets are alternately disposed along the circumferential direction. A long pocket houses two balls. A short pocket houses one ball. Two ball housing sections connected by a slit are formed in the long pocket by projections that project towards a long pocket inner side being provided on opposing long sides of the long pocket.

Fixed constant-velocity universal joint

A fixed constant velocity universal joint is made compact, has little decrease in load capacity even at an operating angle, and can improve high angle strength and durability through lessening instances in which a ball runs over a track at a high angle. A cage includes four pockets, a pair of long pockets of which a circumferential direction spacing is wide and a pair of short pockets of which the circumferential direction spacing is narrow. The long pockets are shifted by 180 degrees along a circumferential direction and the short pockets are shifted by 180 degrees along the circumferential direction. The long pockets and the short pockets are alternately disposed along the circumferential direction. A long pocket houses two balls. A short pocket houses one ball. An offset amount in the cage is made large to be almost the same as an offset amount of track grooves. Track grooves on a joint inner side are deepened and cage thickness on an opening side is increased.

The constant velocity universal joint includes a plurality of vehicle body attachment flanges provided apart from each other in the outer circumferential direction of the joint outer ring and partly protruding in the radial direction. The joint outer ring has a flower outer circumferential shape corresponding to the inner circumferential shape, and the vehicle body attachment flanges are provided at outer recesses positioned between the track grooves of the joint outer ring. In this joint, the number of the balls is six, and the pitches of the ball tracks are random, unequal and not less than 55.

Sliding type constant velocity universal joint

The constant velocity universal joint includes a plurality of vehicle body attachment flanges provided apart from each other in the outer circumferential direction of the joint outer ring and partly protruding in the radial direction. The joint outer ring has a flower outer circumferential shape corresponding to the inner circumferential shape, and the vehicle body attachment flanges are provided at outer recesses positioned between the track grooves of the joint outer ring. In this joint, the number of the balls is six, and the pitches of the ball tracks are random, unequal and not less than 55 degree.

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Iwata, Japan

Manabu Hoshino