Patent ID: 7856951
Filing Date: 2010-12-28
Classification: F01P

Abstract:
1. A hydraulically driven cooling fan control apparatus, comprising: a hydraulic pump that is driven by an engine; a hydraulic motor that is driven by hydraulic oil ejected from the hydraulic pump, and rotates in a forward rotational direction or a reverse rotational direction in accordance with a direction of the supplied hydraulic oil; capacity adjusting means for adjusting a capacity of the hydraulic pump or the hydraulic motor; a hydraulically driven cooling fan that is driven by the hydraulic motor; a switching valve that has a forward rotation position and a reverse rotation position, and upon being switched to the forward rotation position, supplies the hydraulic oil ejected from the hydraulic pump in a direction corresponding to the forward rotational direction of the hydraulic motor, and upon being switched to the reverse rotation position, supplies the hydraulic oil ejected from the hydraulic pump in a direction corresponding to the reverse rotational direction of the hydraulic motor; a reversing switch that is operated to reverse a switch position of the switching valve, and outputs a reversal processing commencement instruction signal; and control means for, in response to input of the reversal processing commencement instruction signal, and under a condition that a rotational speed of the engine has decreased to not more than a stipulated rotational speed, controlling the capacity adjusting means, so as to reduce the capacity of the hydraulic pump or the hydraulic motor, and thus reduce a rotational speed of the hydraulically driven cooling fan, and then reversing the switch position of the switching valve.