A vehicle comprises a hydromechanical automatic gearbox, an automatic gear shift unit (12) connected to a pressure fluid feeding pump (15). The gearbox comprises an input shaft (4) extending from an engine, gearing (23) extending to each gear step, wherein the gearing (23) is mounted on the input shaft (4) and is as a central gear (2), located on the input shaft (4), meshing with gear wheels (3) of different gear steps having different diameters mounted on the input shaft (4) of a single hydraulic torque converter (5) comprising a pump (6) and a turbine (8) located accordingly on the input (4) and output (7) shafts thereof forming a flow path of pressure fluid, each of the hydraulic torque converter (5) is electronically and hydraulically linked to the gear shift unit (12) of the vehicle.

The variable speed transmission uses multiple fluid couplings to provide a sturdy, durable variable output ratio transmission by using hydraulic fluid to vary the output. Each fluid coupling has an independent output shaft driven by the respective fluid coupling turbine. Output shafts drive alternate gears (i.e., first and third at a first fluid coupling and second and fourth at a second fluid coupling). This configuration alternates gear shifts between the fluid couplings allowing the next gear up or down to be engaged before disengaging the current gear, for uninterrupted gear changes in both up and down shifting. A fifth gear would be driven by a gear connected to the fluid coupling input shafts. Gears could be engaged with hydraulic clutches or syncromesh gears. This combined with variable slip fluid couplings allows for better torque and control.

The variable speed transmission uses multiple fluid couplings to provide a sturdy, durable variable output ratio transmission by using hydraulic fluid to vary the output. Each fluid coupling has an independent output shaft driven by the respective fluid coupling turbine. Output shafts drive alternate gears (i.e., first and third at a first fluid coupling and second and fourth at a second fluid coupling). This configuration alternates gear shifts between the fluid couplings allowing the next gear up or down to be engaged before disengaging the current gear, for uninterrupted gear changes in both up and down shifting. A fifth gear would be driven by a gear connected to the fluid coupling input shafts. Gears could be engaged with hydraulic clutches or syncromesh gears. This combined with variable slip fluid couplings allows for better torque and control.

A hydraulic mechanical transmission includes a first hydraulic unit having a first shaft and a second hydraulic unit having a second shaft. The second hydraulic unit is connected in hydraulic fluid communication with the first hydraulic unit by high and low pressure lines. At least one of the first and second hydraulic units has variable displacement. A mechanical torque transfer arrangement transfers torque between the first shaft and the rotatable component of the second hydraulic unit. One of the first and second hydraulic units operates as a hydraulic pump and the other of the first and second hydraulic units operates as a hydraulic motor.

A hydraulic mechanical transmission includes a first hydraulic unit having a first shaft and a second hydraulic unit having a second shaft. The second hydraulic unit is connected in hydraulic fluid communication with the first hydraulic unit by high and low pressure lines. At least one of the first and second hydraulic units has variable displacement. A mechanical torque transfer arrangement transfers torque between the first shaft and the rotatable component of the second hydraulic unit. One of the first and second hydraulic units operates as a hydraulic pump and the other of the first and second hydraulic units operates as a hydraulic motor.

The invention relates to a hydrodynamic transmission gear-box that contains two pump wheels, which are round flat disks, on the front peripheral part of which installed firmly are radially directed blades. The first wheel is rigidly connected to the input shaft. The second and subsequent pump wheels, each with a diameter greater than the previous one, are mounted with their own hubs onto the hubs of the preceding pump wheels with the possibility of free rotation on them. On the back side of each disk, a device is installed to block it with the next pump wheel, and the last pump wheel—with the turbine wheel. The turbine wheel is mounted on the input shaft and in the crankcase of the drive device on bearings and is connected to vehicle's reverse mechanism and running gear. Reduction in weight and size, increase of service life and performance improvement are achieved.

A hydraulic mechanical transmission includes a first hydraulic unit having a first shaft and a second hydraulic unit having a second shaft. The second hydraulic unit is connected in hydraulic fluid communication with the first hydraulic unit by high and low pressure lines. A valve having a variable orifice is positioned along the high and low pressure lines, and at least one of the first and second hydraulic units has a variable displacement. A mechanical torque transfer arrangement transfers torque between the first shaft of the first hydraulic unit and a rotatable component of the second hydraulic unit. In use, one of the first and second hydraulic units operates as a hydraulic pump and the other of the first and second hydraulic units operates as a hydraulic motor.

A hydraulic mechanical transmission includes a first hydraulic unit having a first shaft and a second hydraulic unit having a second shaft. The second hydraulic unit is connected in hydraulic fluid communication with the first hydraulic unit by high and low pressure lines. A valve having a variable orifice is positioned along the high and low pressure lines, and at least one of the first and second hydraulic units has a variable displacement. A mechanical torque transfer arrangement transfers torque between the first shaft of the first hydraulic unit and a rotatable component of the second hydraulic unit. In use, one of the first and second hydraulic units operates as a hydraulic pump and the other of the first and second hydraulic units operates as a hydraulic motor.

A vehicle comprises a hydromechanical automatic gearbox, an automatic gear shift unit (12) connected to a pressure fluid feeding pump (15). The gearbox comprises an input shaft (4) extending from an engine, gearing (23) extending to each gear step, wherein the gearing (23) is mounted on the input shaft (4) and is as a central gear (2), located on the input shaft (4), meshing with gear wheels (3) of different gear steps having different diameters mounted on the input shaft (4) of a single hydraulic torque converter (5) comprising a pump (6) and a turbine (8) located accordingly on the input (4) and output (7) shafts thereof forming a flow path of pressure fluid, each of the hydraulic torque converter (5) is electronically and hydraulically linked to the gear shift unit (12) of the vehicle.

A hydraulic mechanical transmission includes a first hydraulic unit having a first shaft and a second hydraulic unit having a second shaft. The second hydraulic unit is connected in hydraulic fluid communication with the first hydraulic unit by high and low pressure lines. At least one of the first and second hydraulic units has variable displacement. A mechanical torque transfer arrangement transfers torque between the first shaft and the rotatable component of the second hydraulic unit. One of the first and second hydraulic units operates as a hydraulic pump and the other of the first and second hydraulic units operates as a hydraulic motor.