A road milling machine includes a machine frame, at least three travelling devices, a milling drum, and at least one hydraulic drive system. The hydraulic drive system includes at least one hydraulic pump, at least one hydraulic fixed displacement motor for driving at least one driven travelling device, and one each hydraulic variable displacement motor for driving the remaining travelling devices. A first gearbox is arranged between the fixed displacement hydraulic motor and its associated travelling device. One each second gearbox is arranged between each of the hydraulic variable displacement motors and their associated travelling devices. The transmission ratio of the first gearbox is lower than the transmission ratios of the second gearboxes and/or the displacement volume of the fixed displacement motor is smaller than the maximum displacement volume of the variable displacement motors.

A power split and power convergence combined hydro-mechanical hybrid transmission device includes an input member, a power split mechanism, a mechanical transmission mechanism, a power convergence mechanism, an output member, a hydraulic transmission mechanism, a clutch assembly, and a brake assembly. The input member is connected to the power split mechanism, the power convergence mechanism is connected to the output member, and the clutch assembly connects an output end of the power split mechanism to an input end of the mechanical transmission mechanism and an input end of the hydraulic transmission mechanism and connects an input end of the power convergence mechanism to an output end of the mechanical transmission mechanism and an output end of the hydraulic transmission mechanism. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input member and the output member.

A power split and power convergence combined hydro-mechanical hybrid transmission device includes an input member, a power split mechanism, a mechanical transmission mechanism, a power convergence mechanism, an output member, a hydraulic transmission mechanism, a clutch assembly, and a brake assembly. The input member is connected to the power split mechanism, the power convergence mechanism is connected to the output member, and the clutch assembly connects an output end of the power split mechanism to an input end of the mechanical transmission mechanism and an input end of the hydraulic transmission mechanism and connects an input end of the power convergence mechanism to an output end of the mechanical transmission mechanism and an output end of the hydraulic transmission mechanism. The clutch assembly and the brake assembly provide a continuous transmission ratio between the input member and the output member.

A pump assembly for a motor vehicle, comprising at least one mechanical drive, at least one electric drive, and at least one planetary gearbox, wherein the mechanical drive and the electric drive are coupled to one another via the planetary gearbox, the electric drive comprising a rotor shaft that is designed as a hollow shaft, wherein the rotor shaft is mounted at one side on a housing of the pump assembly via a ball bearing and at the other side in a gear stage of the planetary gearbox.

A pump assembly for a motor vehicle, comprising at least one mechanical drive, at least one electric drive, and at least one planetary gearbox, wherein the mechanical drive and the electric drive are coupled to one another via the planetary gearbox, the electric drive comprising a rotor shaft that is designed as a hollow shaft, wherein the rotor shaft is mounted at one side on a housing of the pump assembly via a ball bearing and at the other side in a gear stage of the planetary gearbox.

In a transmission structure according to this invention, speed change ratios of input side first and second transmission mechanisms are set so that the rotational speed of a planetary second element is the same when an HST output is set to a second HST speed in either a first transmission state or a second transmission state, and the rotational speed of a planetary first element is the same when the HST output is set to the second HST speed in either the second transmission state or the first transmission state. The speed change ratios of an output side first and second transmission mechanisms are set so that the rotational speed developed in a speed change output shaft when the HST output is set to the second HST speed is the same in either the first or second transmission states.

In a transmission structure according to this invention, speed change ratios of input side first and second transmission mechanisms are set so that the rotational speed of a planetary second element is the same when an HST output is set to a second HST speed in either a first transmission state or a second transmission state, and the rotational speed of a planetary first element is the same when the HST output is set to the second HST speed in either the second transmission state or the first transmission state. The speed change ratios of an output side first and second transmission mechanisms are set so that the rotational speed developed in a speed change output shaft when the HST output is set to the second HST speed is the same in either the first or second transmission states.

Methods and systems for a hydromechanical transmission in a vehicle are provided herein. In one example, the transmission system includes a hydrostatic assembly with a hydraulic pump in fluidic communication with a hydraulic motor. The transmission system further includes a controller configured to selectively transition between a torque control mode and a speed control mode of the hydrostatic assembly while the vehicle is on a slope.

Methods and systems for a hydromechanical transmission are provided herein. In one example, a vehicle system is provided that includes a hydromechanical transmission with a power-take off (PTO) that is designed to rotationally couple to an implement. The vehicle system further includes an engine coupled to the hydromechanical transmission and a power-management control unit configured to, during a drive or coast condition, cause the power-management control unit to: determine a net available power for the hydromechanical transmission and manage a power flow between the hydromechanical transmission, a drive axle, and the implement based on the net available power.

Methods and systems for a hydromechanical transmission are provided herein. In one example, a vehicle system is provided that includes a hydromechanical transmission with a power-take off (PTO) that is designed to rotationally couple to an implement. The vehicle system further includes an engine coupled to the hydromechanical transmission and a power-management control unit configured to, during a drive or coast condition, cause the power-management control unit to: determine a net available power for the hydromechanical transmission and manage a power flow between the hydromechanical transmission, a drive axle, and the implement based on the net available power.