| 摘要 |
PURPOSE:To always keep maximum acceleration of an actuator constant, by increasing a maximum set speed, limiting an operating speed of a displacement variable mechanism of a variable displacement oil hydraulic pump, correspondingly to a decrease of speed of a prime mover as a power supply source of said pump. CONSTITUTION:Since at maximum speed value of a prime mover 8, output ratio of a speed detector 9 is 1, a divider 1 outputs a value i.e. maximum set speed from a maximum set speed generator circuit 10 divided by 1, that is, a value of the maximum set speed as it is to an arithmetic unit 6. Accordingly, operating speed of a displacement variable mechanism 3 of a variable displacement oil hydraulic pump 1 is limited to not more then the maximum set speed. On the other hand, if the speed of the prime mover 8 is decreased to, for instance, 1/2 times the maximum value, the divider 11 divides the maximum set speed with 0.5 to double the maximum set speed. In consequence, a limited value of operating speed of said mechanism 3 increases inversely proportionally to speed, and maximum acceleration of an actuator 2 becomes the same value as the speed of the prime mover. |
