| 摘要 |
This invention consists of two or more fixed displacement hydraulic pump/motors mounted on a common input shaft hydraulically connected to two or more fixed hydraulic pump/motors mounted on a common output shaft. The relative displacements of the pump/motors are chosen such that by selectively activating the individual pump/motors, the transmission ratio can be changed in the case when the input devices and acting as pumps driving the output devices as motors (conversely when driving the vehicle in reverse). Further, a hydraulic accumulator and reservoir are attached in a manner that allows the pressurized fluid to augment the flow produce by the input pumps in order to increase the transmission ratio. Similarly, the transmission ratio can also be reduced by causing the input pumps to pump fluid into the accumulator at the same time they are pumping fluid through the output motors. The transmission also contains a single speed all mechanical by-pass for use when cruising and an input reduction gear to increase the torque and power capacity of the transmission. A further feature of the transmission is a valve arrangement that allows the transmission to generate a continuously variable braking torque when the transmission is used to supply braking force to the vehicle. In addition, the transmission includes a selectable, one-way clutch that connects the input directly to the output. When engaged, this clutch provides an all mechanical by-pass to the hydraulic transmission for use when cruising in order to improve the efficiency.
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