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.

An automobile or other wheeled vehicle includes various hydraulic components, including a hydraulic gearbox, transmission, clutch, and brake energy recovery system. Such hydraulic components supplement or replace traditional mechanical components of the automobile or other wheeled vehicle to improve the overall operational efficiency thereof.

A work machine control system includes an operational input portion that accepts an input operation to change a position of acceptance, maintains the position of acceptance when there is no input operation accepted, and provides an operation command in accordance with change in position of acceptance, an operational force providing portion that provides a plurality of operational forces in correspondence with an amount of change of the position of acceptance, a transmission portion that changes a speed of rotation provided from a drive source to transmit resultant rotation to a drive wheel, and a controller that controls the transmission portion based on a travel speed of the drive wheel in accordance with the operation command.

A multi-pump driven single-motor hydro-mechanical hybrid transmission device includes an input shaft, a planetary gear split mechanism, a hydraulic transmission system, a planetary gear convergence mechanism, and an output shaft. The input shaft is connected to the hydraulic transmission system and the planetary gear convergence mechanism through the planetary gear split mechanism. The hydraulic transmission system and the planetary gear convergence mechanism are both connected to the output shaft. The hydraulic transmission system includes a multi-pump driving mechanism, a fixed displacement motor mechanism, and a hydraulic transmission output mechanism. The multi-pump driving mechanism is connected to the fixed displacement motor mechanism. The fixed displacement motor mechanism is connected to the planetary gear convergence mechanism and is connected to the output shaft through the hydraulic transmission output mechanism.

A multi-pump driven single-motor hydro-mechanical hybrid transmission device includes an input shaft, a planetary gear split mechanism, a hydraulic transmission system, a planetary gear convergence mechanism, and an output shaft. The input shaft is connected to the hydraulic transmission system and the planetary gear convergence mechanism through the planetary gear split mechanism. The hydraulic transmission system and the planetary gear convergence mechanism are both connected to the output shaft. The hydraulic transmission system includes a multi-pump driving mechanism, a fixed displacement motor mechanism, and a hydraulic transmission output mechanism. The multi-pump driving mechanism is connected to the fixed displacement motor mechanism. The fixed displacement motor mechanism is connected to the planetary gear convergence mechanism and is connected to the output shaft through the hydraulic transmission output mechanism.

In a self-propelled construction machine (1), in particular road milling machine, comprising a machine frame (8), at least three travelling devices (12, 16), at least one working device, in particular a milling drum (6), for working the ground pavement (3), at least one hydraulic drive system (70) for driving at least two travelling devices (12, 16), wherein the hydraulic drive system (70) comprises at least one hydraulic pump (78), wherein the hydraulic drive system (70) comprises at least one hydraulic fixed displacement motor (74) for driving at least one driven travelling device, and one each hydraulic variable displacement motor (72) for driving the remaining driven travelling devices that are not driven by a fixed displacement motor (74), wherein a first gearbox (90) is arranged between the fixed displacement motor (74) and the associated travelling device, and wherein one each second gearbox (92) is arranged between the remaining driven travelling devices and the respective hydraulic variable displacement motors (72),

it is provided for the following features to be achieved: the transmission ratio of the first gearbox between the fixed displacement motor (74) and the associated travelling device is lower than the respective transmission ratios of the second gearboxes (92), which are each arranged between the respective hydraulic variable displacement motors (72) and the respective travelling device, and/or the displacement volume of the fixed displacement motor (74) is smaller than the maximum displacement volume of the variable displacement motors (72).

An automobile or other wheeled vehicle includes various hydraulic components, including a hydraulic gearbox, transmission, clutch, and brake energy recovery system. Such hydraulic components supplement or replace traditional mechanical components of the automobile or other wheeled vehicle to improve the overall operational efficiency thereof.

Various vehicle systems capable of different operation modes are disclosed. According to one example, the system can include at least one input shaft, at least one output shaft, a plurality of hydraulic devices, and one or more accessories. The plurality of hydraulic devices can be configured to be operable as vane pumps in a retracted vane mode of operation and can be configured to be operable as a hydraulic couplings to couple the at least one input shaft with the at least one output shaft in a vane extended mode of operation. The plurality of hydraulic devices can be simultaneously operable as the hydraulic couplings and the vane pumps. The one or more accessories can be in fluid communication with the plurality of hydraulic devices and can be configured to receive a hydraulic fluid pumped from one or more the plurality of hydraulic devices when operating as the vane pumps.

A transmission including a hydraulic unit (advancing clutch, backing clutch, constant velocity clutch, acceleration clutch, and PTO clutch) which operates with a working fluid; and a housing (transmission housing) which accommodates or supports the hydraulic unit 321, 322, 341, 342, 351). The housing structures a passage for guiding a working fluid to the hydraulic unit. In the housing, an oil chamber is formed on an attachment seating surface of the hydraulic pump, and the oil chamber is plugged by the hydraulic pump.

A method of drivingly engaging a first motor of a dual motor drive unit with an output shaft driven by a second motor of the dual motor drive unit includes actuating a clutching device for drivingly engaging the first motor with the output shaft. Next, a rotational speed of the first motor is synchronized with a rotational speed of the output shaft. When the rotational speed of the first motor and the rotational speed of the output shaft are synchronized, an output torque of the first motor is reduced. When the clutching device drivingly engages the first motor with the output shaft, the output torque of the first motor is increased. The invention further relates to a dual motor drive unit for carrying out the method.