| 摘要 |
PURPOSE:To increase rigidity of a shaft with increased number of projecting parts by combining an outer cylinder having U-shaped grooves of a same depth between three, equally spaced projecting ridges and a spline shaft having six, equally spaced projecting parts. CONSTITUTION:Three equally spaced projecting ridges 1a's are formed in the axial direction on the inner periphery of an outer cylinder 1, orbit grooves 1b's loaded by balls 3's are formed on both sides of the projecting ridges 1a's, and U-shaped grooves 1c's between the projecting ridges 1a's are formed to have an approximately same depth. A retainer 4 is fixed on the inner surface of the outer cylinder 1 to form return windows for balls 3's symmetrically on both sides of the center line of the U-shaped grooves 1c's, with orbit windows having a width slightly smaller than the ball diameter arranged in the axial direction at orbit grooves. A spline shaft 2 has six projecting parts 2a's to form orbit grooves between parts contacting the balls 3's. Thus, shape of the outer cylinder is simplified, production cost is lowered with higher accuracy, shaft rigidity is increased with increased number of projecting parts, and the overall height of the bearing cross section can be made smaller.
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