JPS6439385A - Formation of dynamic pressure generating groove of dynamic-pressure fluid bearing - Google Patents

Abstract

PURPOSE:To form the title dynamic pressure generating groove which is not deformed when printed by reducing the entire length of the ink transfer part of a printing matrix, and providing a specified auxiliary non-ink transfer part. CONSTITUTION:Plural dynamic pressure generating grooves 3 are formed in the circumferential direction at regular intervals on the dynamic pressure generating part 2 having prescribed width in the axial direction on the outer periphery of a shaft 20. The entire length La of the ink transfer part 9 of the printing matrix 21 used therefor is made slightly smaller than the circumference (denoted by L2) of the generating part 2, and the rectangular auxiliary non-ink transfer part 22 is provided at the center of the transfer part 9 in the longitudinal direction over the entire width of the transfer part 9. The width (a) of the non-ink transfer part 22 in the lengthwise direction of the matrix 21 is equal to the numerical difference between the lengths L2 and La. When the generating part 2 of the shaft 20 is printed by using the matrix 21, a non- printed part 23 extending to a joint A between the print starting and ending positions Ps and Pe is inevitably formed over the entire width of the generating part 2 even if there are some errors in the length La and L2. Accordingly, the joint A is not shifted, and the need for the adjustment of the printed shape can be eliminated.