A system, for providing a rotary power to an implement of a machine, includes a first motor control valve associated with a first motor of the machine and a second motor control valve associated with a second motor of the machine. The first motor control valve is configured to be actuated at a first shift point to shift the first motor such that the first motor and the second motor switch between a first implement drive speed and a second implement drive speed. The second motor control valve is configured to be actuated at a second shift point to shift the second motor such that the first motor and the second motor switch between the second implement drive speed and a third implement drive speed. The first and second shift points are based on loading of the implement during operation. In addition, the first and second shift points are different.

A work vehicle includes a power source, a travel device, a power transmission device, and a control device. The power transmission device includes a hydrostatic continuously variable transmission having a relief valve capable of setting a relief pressure, and is configured to transmit power of the power source to the travel device. The control device includes a relief pressure setting unit configured to set the relief pressure of the relief valve in accordance with a target output value of the travel device.

Provided is a loading vehicle in which a control characteristic of traction force can be easily and finely set and changed while a configuration of a hydraulic circuit is simple. An HST traveling driven wheel loader includes an electronically controlled HST pump and HST motor, including a solenoid proportional pressure reducing valve to control displacement volume of the HST pump based on a control signal output from a controller. The controller stores characteristic tables indicating a correlation between discharge pressure of a loading hydraulic pump or an operation state of an engine and a maximum discharge pressure of the HST pump, and when the vehicle speed corresponds to work requiring traction force, outputs a control signal to the solenoid proportional pressure reducing valve so as to obtain the maximum discharge pressure Pm of the HST pump that corresponds to one of the characteristic tables.

A work vehicle includes an engine, a traveling pump driven by the engine, a hydraulic circuit connected to the traveling pump, a traveling motor connected to the traveling pump via the hydraulic circuit, a rotational speed sensor configured to output a signal indicative of engine speed a hydraulic pressure sensor configured to output a signal indicative of hydraulic pressure of the hydraulic circuit, a controller. The controller receives the signals from the rotational speed sensor and the hydraulic pressure sensor. The controller determines whether the engine is in an over-rotation state based on engine speed. The controller determines an upper limit value of a displacement of the traveling pump based on hydraulic pressure of the hydraulic circuit. The controller limits the displacement of the traveling pump to the upper limit value or less upon determining that the engine is in the over-rotation state.

A work vehicle includes an engine, a traveling pump driven by the engine, a hydraulic circuit connected to the traveling pump, a traveling motor connected to the traveling pump via the hydraulic circuit, a rotational speed sensor configured to output a signal indicative of engine speed a hydraulic pressure sensor configured to output a signal indicative of hydraulic pressure of the hydraulic circuit, a controller. The controller receives the signals from the rotational speed sensor and the hydraulic pressure sensor. The controller determines whether the engine is in an over-rotation state based on engine speed. The controller determines an upper limit value of a displacement of the traveling pump based on hydraulic pressure of the hydraulic circuit. The controller limits the displacement of the traveling pump to the upper limit value or less upon determining that the engine is in the over-rotation state.

A hydrostatic traction drive for a mobile working machine includes a first hydraulic machine coupled to a drive machine, a second hydraulic machine arranged with the first hydraulic machine in a hydraulic circuit and coupled to an output, and an electronic control device. A characteristic diagram of a setpoint driving behavior of the mobile working machine is stored in the electronic control device and is parameterized at least in accordance with at least one driving request.

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 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.

Provided is a loading vehicle in which a control characteristic of traction force can be easily and finely set and changed while a configuration of a hydraulic circuit is simple. An HST traveling driven wheel loader includes an electronically controlled HST pump and HST motor, including a solenoid proportional pressure reducing valve to control displacement volume of the HST pump based on a control signal output from a controller. The controller stores characteristic tables indicating a correlation between discharge pressure of a loading hydraulic pump or an operation state of an engine and a maximum discharge pressure of the HST pump, and when the vehicle speed corresponds to work requiring traction force, outputs a control signal to the solenoid proportional pressure reducing valve so as to obtain the maximum discharge pressure Pm of the HST pump that corresponds to one of the characteristic tables.

Provided is a loading work vehicle capable of improving work efficiency even when working on a slippery road surface. An HST-traveling-drive wheel loader 1 comprises a step-on amount detection sensor 610, a discharge pressure detection sensor 75, a mode switch device 60, and a controller 5. The controller 5 is configured to: determine whether a limit mode is selected by the mode switch device 60; specify an operation state of the wheel loader 1 when determining that the limit mode is selected; limit maximum traction force to a first set value which is set based on a static friction coefficient μ and vehicle weight when specifying that a bucket 23 is pushed into a natural ground 100; and increase the maximum traction force from the first set value when specifying that excavation of the natural ground 100 is started.