| 摘要 |
PURPOSE:To make rotation smooth in the case of being used under the magnetic field environment by forming inner and outer bearing rings of steel, and forming rolling elements between both bearing rings of ceramics. CONSTITUTION:When a first joint member 3 is rotated by drive mechanism, attracting force acts between the permanent magnets 8A, 8B of the magnet ring 7 of the first joint member 3 and the permanent magnets 19A, 19B of the magnet ring 18 of a second joint member 15, and the second joint member 15 is rotated by the same quantity in the same direction as the first joint member 3. Since both inner and outer rings 11, 12 and 22, 23 of ball bearings 9, 21 are formed of steel, and the balls 13, 24 of the ball bearings 9, 21 are formed of ceramics, the increase and fluctuation of torque under the influence of the magnetic field can be suppressed. Also, since the magnetic flux is concentrated on the groove 14 of the outer ring 12 and the groove 25 of the inner ring 22, abrasive powder generated from both inner and outer rings 11, 12 and 22, 23 made of steel is collected into the grooves 14, 25 by the attracting force. The abrasive powder is thereby prevented from biting into a raceway track so as to make rotation smooth. |
