| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a dump truck in which horsepower consumed by an engine-driven hydraulic pump is reduced during braking-off to improve its fuel efficiency. <P>SOLUTION: The dump truck includes an oil-cooled center brake 11, a first hydraulic pump 51 for supplying cooling oil to the center brake 11, a second hydraulic pump 52 for supplying cooling oil in addition to the cooling oil from the first hydraulic pump 51 to the brake 11, a hydraulic motor 54 for driving the second hydraulic pump 52, a third hydraulic pump 53 for supplying operating oil to the hydraulic motor 54, a selector valve 55 for bypassing the operating oil to the hydraulic motor 54, and a control device 57 for controlling bypass flow rate at the selector valve 55. The capacity of the first hydraulic pump 51 corresponds to the flow rate of the cooling oil required for lubricating a transmission 6, the capacity of the second hydraulic pump 52 corresponds to the flow rate to cover the cooling oil from the first hydraulic pump 51 during brake-off, and the capacity of the third hydraulic pump 53 is smaller than the capacity of the second hydraulic pump 52. <P>COPYRIGHT: (C)2013,JPO&INPIT |
