Ntn Corporation

Wasaburo Suganuma

Tohru Nakagawa

Manabu Hoshino

Teruaki Fujio

Hiroshi Tone

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 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.

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Iwata, Japan

Wasaburo Suganuma