Universal joint
In a universal joint in which each of shaft portions 1 a of a cross shaft 1 is rotatably supported by: a shell cup 2 which is fitted into a fitting hole 10 x disposed in a fork end portion 10 a of a yoke; and a plurality of needle rollers 3 arranged on an inner circumference 2 y of the bearing cup 2, an annular sealing member 4 for hermetically sealing the opening of the cup 2 is fitted and fixed to a shaft portion outer circumferential face 1 x of the cross shaft 1 via a metal annular member 5. According to the configuration, it is possible to prevent the sealing member 4 from dropping out due to the increase in the internal pressure in attaching the shell cup 2 or the knocking-up by the rollers 3 in operation. A circumferential groove 10 y is formed in an inner circumferential face of the fitting hole 10 x of the yoke, and a retaining ring 7 is disposed in the circumferential groove 10 y. As compared with a conventional method in which the caulking is used for preventing the bearing cup from dropping out, therefore, the positioning of the shell cup 2 in the axial direction is easily performed. In addition, the retaining ring 7 can be easily attached and detached, so that the maintenance for the bearing portion of the universal joint, the exchange of components, and the like can be easily performed in a short period of time.
1 . A universal joint in which each of shaft portions of a cross shaft is rotatably supported by: a bearing cup which is formed into a bottomed cylindrical shape by pressing a plate, and which is fitted into a fitting hole disposed in a fork end portion of a yoke; and a plurality of needle rollers arranged on an inner circumference of said bearing cup, characterized in that
an annular sealing member a lip portion of which is in slide contact with an inner circumferential face of said bearing cup is disposed on an outer circumference of said shaft portion of said cross shaft.
2 . A universal joint according to claim 1 , wherein said lip portion of said sealing member is formed in an inclined shape toward an opening end side of said bearing cup from a root of said lip portion.
3 . A universal joint according to claim 1 or 2 , wherein said sealing member is fitted to said shaft portion via a metal annular member.
4 . A universal joint in which each of shaft portions of a cross shaft is rotatably supported by: a bearing cup which is formed into a bottomed cylindrical shape by pressing a plate, and which is fitted into a fitting hole disposed in a fork end portion of a yoke; and a plurality of needle rollers arranged on an inner circumference of said bearing cup, characterized in that
a circumferential groove is formed in an inner circumference of said fitting hole of said yoke, and a retaining ring for preventing said bearing cup from dropping out in an axial direction of said bearing cup is disposed in said circumferential groove.
5 . A universal joint according to claim 4 , wherein said bearing cup is formed so that a chamfered size in a radial direction of an outer bottom portion of said cup is 4% or less with respect to an outer diameter of said cup.