| 摘要 |
PROBLEM TO BE SOLVED: To provide a power transmission device capable of positively preventing rusting of each ball without tightly sealing a periphery of each ball. SOLUTION: A rustproofing coat 14a is formed on a surface of each ball 14, rust is prevented even moisture adheres to each ball 14, and deterioration of a power cutoff function due to rusting of each ball 14 can be positively prevented. Since rusting of each ball 14 can be prevented without tightly sealing the periphery of each ball 14, high grade dimensional accuracy and another component for sealing are not necessary, and a manufacturing cost can be reduced. Since a lubricant coat 14b is formed on a surface of the rustproofing coat 14a of each ball 14, even when a high contact pressure is applied to each ball 14 and its contacting component for a long time, a coefficient of friction in a contact surface of each ball 14 does not rise by an aging effect, and torque to cutoff power can be maintained at set torque. COPYRIGHT: (C)2005,JPO&NCIPI
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