| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a dynamic pressure generating groove easily with a numerically controlled lathe by forming this dynamic pressure generating groove with an inclined groove part obliquely extending at the specified angle with the circumferential direction, and a circumferential groove part extending in the circumferential direction from one end of the inclined groove part. SOLUTION: A dynamic pressure generating groove 13 has a pair of first and second inclined groove parts 13a and 13b with almost symmetrical groove form, and it is also provided with a central part circumferential groove 13c where these paired inclined groove parts 13a and 13b are joined together. In this circumferential groove 13c, these first and second inclined groove parts 13a and 13b, extending as far as the specified length in the circumference, and obliquely extend to a groove center line X. These first and second inclined groove parts 13a and 13b make into the specified angleθwith the circumferential direction, and their ends at the downstream side in the rotational direction C of each turning shaft of these inclined groove parts 13a and 13b are joined together via the circumferential groove part 13c and interconnected with each other. With this constitution, this dynamic pressure generating groove 13 is easily formable by a numerically controlled lathe.
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