Abstract: Improvements to a hydro-mechanical transmission based on fixed displacement pump/motors rather than variable displacement pump/motors are disclosed. These include rpm-changing gears on the input and the output pump/motors which allow the pump/motors to be operated at their maximum rated rpm and facilitate compact packaging. A novel selectable clutch configuration is part of the packaging arrangement. The addition of a two-speed all mechanical transmission on the output extends the useful range of a mechanical bypass of the hydraulic transmission intended for cruising.

Abstract: This invention consists of the addition of a novel clutch arrangement which facilitates speed changing gears on both the output and input of the transmission and provides for a compact packaging configuration for a plurality of hydraulic pump/motors. The use of a small accumulator without a valve and a related reservoir absorbs the pressure shocks from rapidly opening and closing the valves that that select or de-select the pump/motors. It is also disclosed that two adjacent pump/motors on the same shaft can be constructed such that they share an input or output port thereby reducing the size of the combination. The transmission can perform the retarder function by placing a flow retarding valve in the re-circulating path in one or more of the pump/motors.

Abstract: A vehicle transmission consisting of two or more fixed displacement hydraulic pumps mounted on a common shaft (input) which provide the fluid to drive one or more fixed displacement hydraulic motors on a second common shaft (output) and a means of selectively activating and deactivating the pumps and motors to change the rotational speed of the second shaft with respect to the first shaft. The two shafts are connected by a selectable one way clutch to allow the hydraulic elements to be bypassed under certain operating conditions. Variations include the use of a reduction gear driving the input shaft and a two or more speed mechanical transmission on the output shaft. A hydraulic reservoir and accumulator are provided for energy storage and to accomplish instantaneous torque control. When used to provide hydraulic regenerative braking, the roles of pumps and motors are reversed.

Abstract: 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.

Abstract: This invention describes two types of mechanical clutches; a selectable one-way clutch and a two-way or dog clutch. Both clutches are constructed with sprags mounted on an axis that is tilted with respect to the axis of the shafts being connected by the clutches. Both engagement faces of the clutch are conical and parallel such that the clutches can be disengaged by withdrawing one of the clutch plates along the line of the shafts being connected. Sprags produce a one-way clutch. In the dog clutch, alternate sprags are mounted opposite to its neighbor, so the clutch is prevented from slipping in either direction.

Abstract: 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.