A mixer drum driving apparatus includes an auxiliary fluid pressure pump that is provided independently of a fluid pressure pump and is capable of supplying a working fluid to a fluid pressure motor so as to cause a mixer drum to perform agitation rotation, a plurality of motors configured to drive the auxiliary fluid pressure pump to rotate, and a control unit that controls rotation of the mixer drum. When an engine is stopped during the agitation rotation of the mixer drum, the control unit drives the auxiliary fluid pressure pump to rotate by operating the plurality of motors selectively in accordance with a load of the mixer drum.

A hydraulic control system for control of a hydraulic motor. The hydraulic control system comprises a fluid distribution assembly having a tank, a pump to pump fluid from the tank and a directional valve for distributing pressurised fluid from the pump and to return fluid to the tank; a valve assembly fluidly connected to the directional valve, the valve assembly having a first overcenter valve and a pressure reducing valve wherein a first main line connects the directional valve to the first overcenter valve and wherein a shuttle line connects the pressure reducing valve to the first main line; a hydraulic motor fluidly connected to the valve assembly wherein the first main line connects the hydraulic motor to the first overcenter valve; and a brake assembly fluidly connected to the pressure reducing valve, wherein a drain line connects the pressure reducing valve to the hydraulic motor.

The present invention relates to a system for assisting the driving of a vehicle comprising at least one hydraulic machine forming a pump (19), at least one hydraulic machine forming an engine (130, 140) and an open hydraulic circuit (100) extending through a tank (13) and comprising a suction duct (11) extending from the tank (13) to an inlet of the pump (19), a supply duct (15) extending from the outlet of the pump (19) to the inlet of the engine (130, 140) and a return duct (122) extending from the outlet of the engines (130, 140) to the tank (13), characterised in that at least one of the engines (130, 140) is an engine that can disengage the clutch, and in that the system comprises an element forming a restriction (180) and creating a loss of charge over the return duct and a means (190, 192) adapted for connecting to the engine casing, the part of the return duct (122) located upstream of the element forming a restriction (180) and for applying to the engine casing, from the return duct (122), a pressure lower than the pressure of this return duct.

The present invention relates to a system for assisting the driving of a vehicle comprising at least one hydraulic machine forming a pump (19), at least one hydraulic machine forming an engine (130, 140) and an open hydraulic circuit (100) extending through a tank (13) and comprising a suction duct (11) extending from the tank (13) to an inlet of the pump (19), a supply duct (15) extending from the outlet of the pump (19) to the inlet of the engine (130, 140) and a return duct (122) extending from the outlet of the engines (130, 140) to the tank (13), characterised in that at least one of the engines (130, 140) is an engine that can disengage the clutch, and in that the system comprises an element forming a restriction (180) and creating a loss of charge over the return duct and a means (190, 192) adapted for connecting to the engine casing, the part of the return duct (122) located upstream of the element forming a restriction (180) and for applying to the engine casing, from the return duct (122), a pressure lower than the pressure of this return duct.

A working machine includes a traveling device to change a traveling speed in accordance with a flow rate of an operation fluid, a traveling operation device to change the flow rate of the operation fluid to be supplied to the traveling device, and a switching operation portion to change, at multiple steps, a supply amount of the operation fluid to be supplied to the traveling device, the supply amount corresponding to an operation extent of the traveling operation device.

A wheeled work vehicle includes: a transmission transmitting the rotational power of a traveling hydraulic motor to wheels; a traveling control valve having an interruption position that interrupts supply of hydraulic fluid from a hydraulic pump to the traveling hydraulic motor; a shift changeover valve that shifts the speed stage of the transmission by the position of the shift changeover valve being selectively switched; and a controller that controls the traveling control valve and the shift changeover valve. The controller switches the traveling control valve to the interruption position, then switches the position of the shift changeover valve such that the speed stage of the transmission is shifted to the low speed stage, and switches the traveling control valve from the interruption position to an original position side before the switching in a case where the controller shifts the transmission from the high speed stage to the low speed stage.

A mobile work machine has a drive unit for driving at least one drive element and/or a working element. The drive unit is hydromechanical drive unit with at least one internal combustion engine and hydraulic energy transmission unit with at least one hydraulic pump and a hydraulic motor. In normal operation, the motor shaft of the internal combustion engine rotates at a normal speed (n_0). Conversely, in a limit temperature operation in which a sensed actual operating temperature of the internal combustion engine or another part of the drive unit is higher than or equal to a target limit temperature (T_limit), an electrical control unit and/or electronic control unit controls the internal combustion engine in such a way that the motor shaft of the internal combustion engine rotates at a first speed (n_target) that is higher than the normal speed (n_0) of the motor shaft in normal operation.

A wheeled work vehicle includes: a transmission transmitting the rotational power of a traveling hydraulic motor to wheels; a traveling control valve having an interruption position that interrupts supply of hydraulic fluid from a hydraulic pump to the traveling hydraulic motor; a shift changeover valve that shifts the speed stage of the transmission by the position of the shift changeover valve being selectively switched; and a controller that controls the traveling control valve and the shift changeover valve. The controller switches the traveling control valve to the interruption position, then switches the position of the shift changeover valve such that the speed stage of the transmission is shifted to the low speed stage, and switches the traveling control valve from the interruption position to an original position side before the switching in a case where the controller shifts the transmission from the high speed stage to the low speed stage.

A hydrostatic assembly includes a pressure medium with a variable viscosity and a control device through which at least one process variable or state variable of the hydrostatic assembly is open-loop or closed-loop controlled as a function of the viscosity. The hydrostatic assembly further includes a temperature sensing device configured to sense a temperature of the pressure medium.

A counter balance valve (71L) is located between a directional control valve (23) and a hydraulic motor (32L) and provided on the way of a pair of supply/discharge lines (25A, 25B). The counter balance valve (71L) allows a spool (72L) to be displaced axially based on a pressure difference between the supply/discharge lines (25A, 25B). The counter balance valve (71L) includes a communicating passage (73L) for communicating the supply/discharge lines (25A, 25B) when the displacement of the spool (72L) exceeds a predetermined amount (X.sub.CM), based on a pressure difference between the supply/discharge lines (25A, 25B). The communicating passage (73L) is provided in the spool (72L) of the counter balance valve (71L).