A device is described for transmitting mechanical power that allows variable output-speed to input-speed ratios. Gear sets such as epicyclic gear sets have components that rotate about a common axis selectively at the same rotational speed and at different relative rotational speeds as determined by at least one of fluid flow and fluid pressure. One or more inlet ports and fluid passageways introduce a working fluid into one or more volume spaces between the components. The internal pressure and flow of the working fluid through the device is controlled to provide substantially infinite variability of the output-speed to input-speed ratios for applications where, for example, an engine provides the mechanical power for propelling a vehicle.

A slip control method and arrangement for a driveline including a continuously variable transmission is described herein. The driveline includes a hydraulic slip arrangement that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the hydraulic slip arrangement prevents the prime mover from stalling.

The SIVRT disclosed includes a unique, ordered geartrain; it allows a large-continuous range of input:output velocity ratios (forward or reverse). This range is controlled by fluid-coupled gearsets which direct the power flow to the output shaft. The SIVRT requires no torque converter or friction clutches and has been designed for fully-loaded work machines which must operate reliably at creep speeds for extended periods with 1-3 stop-reverse-stop-forward operations every minute of the workshift. The clutchless variformer system disclosed herein provides a robust, heavy-duty, continuously-variable mechanical transmission especially designed and scaled for applications in vehicles and working machines which operate at creep speeds with frequently stop-start-reverse activity.

Disclosed is a method for operating a drive train having a drive shaft (2), a prime mover (4) connected to an electrical grid (12), and a differential gearing (3) having a total of three input and output elements, an output element being connected to the drive shaft (2), one input element to the prime mover (4) and a second input element to a differential drive (5). A work machine (1) is connected to the drive shaft (2) and a portion of the performance of the work machine (1) is dissipated by a choke (22) or diverted by a valve, a flap or a bypass (32).

A hydrostatic clutch system for dually charging the accumulators while speeding up and slowing down. The hydrostatic clutch system includes a hydraulic pump having a pump housing with openings therein; a manifold/end cover; and a fluid circuit assembly in operable communication with the hydraulic pump. The hydrostatic clutch system may be used with at least one transmission or gear set in operable communication with the hydrostatic clutch. The hydrostatic clutch system may be used to create a variable speed from a fixed input speed. The hydrostatic clutch system may also be used as a hybrid system by changing the pump into a motor for launch and for powering the vehicle with the engine disconnected using accumulated hydraulic pressure. The hydrostatic clutch system captures the resistance of the weight of the vehicle in order to make power while the vehicle is accelerating.

A slip control method and arrangement for a driveline including a continuously variable transmission is described herein. The driveline includes a hydraulic slip arrangement that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the hydraulic slip arrangement prevents the prime mover from stalling.