| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable speed control device preventing a variable speed actuator from being large by homogenizing a play reducing elastic force of a variable speed link mechanism over the whole variable speed zone. SOLUTION: A motor 9 is rotationally driven to a place corresponding to a target variable speed ratio, and rotates the variable speed link 14 in a corresponding direction through a pin 13 around a pin 19. In response to the rotation, a spool 8 of a variable speed control valve 7 produces variable speed by output pressure control corresponding to a stroke direction. A progressing state of variable speed is fed-back to the variable speed link 14 through a feed-back link 18 by cam action of a pin 20 and a slit 21a as rotation of a cam plate 21. As the variable speed advances, the spool 8 is returned to an original neutral position. In order to prevent looseness of the variable speed link mechanism, a play reducing spring 24 is stretched between the pin 20 and the cam plate 21, and the pin 20 is pressed to an inner peripheral surface of the slit 21a of the cam plate 21. A length of a play reducing spring 24 is invariably maintained with a locking portion (pin 15) of the play reducing spring 24 for the cam plate 21 as a curvature center of an inner peripheral surface of the slit 21a.
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