A hydrostatic traction drive includes a hydraulic pump for supplying pressure medium to a hydraulic motor of the traction drive. The hydraulic pump has an actuation cylinder with at least one cylinder space and a swept volume which can be adjusted thereby. At least one electrically actuable pressure valve is provided, by means of which an actuation pressure which has an adjusting effect can be applied to the cylinder space. In addition, the traction drive has a device by means of which a pressure of the hydraulic pump can be limited by influencing the actuation pressure.

A hydrostatic traction drive includes a hydraulic pump for supplying pressure medium to a hydraulic motor of the traction drive. The hydraulic pump has an actuation cylinder with at least one cylinder space and a swept volume which can be adjusted thereby. At least one electrically actuable pressure valve is provided, by means of which an actuation pressure which has an adjusting effect can be applied to the cylinder space. In addition, the traction drive has a device by means of which a pressure of the hydraulic pump can be limited by influencing the actuation pressure.

The invention relates to a hydraulic assistance device comprising: a hydraulic machine (30) capable of driving a wheel (W) of the craft; a variable displacement pump (10) comprising a double-acting actuator (12) defining two control chambers (12a, 12b) for hydraulically controlling the capacity of said pump (10); two supply lines (40a, 40b) that connect the hydraulic machine (30) and the variable displacement pump (30) in order to form a closed circuit, characterised in that the device further comprises: two control lines (80a, 80b), each being respectively drawn from one of the two supply lines (40a, 40b) and being configured to respectively supply one of the two control chambers (12a, 12b); two electrically calibratable pressure limiters (90a, 90b) respectively disposed on the two control lines (80a, 80b).

The invention relates to a hydraulic assistance device comprising: a hydraulic machine (30) capable of driving a wheel (W) of the craft; a variable displacement pump (10) comprising a double-acting actuator (12) defining two control chambers (12a, 12b) for hydraulically controlling the capacity of said pump (10); two supply lines (40a, 40b) that connect the hydraulic machine (30) and the variable displacement pump (30) in order to form a closed circuit, characterised in that the device further comprises: two control lines (80a, 80b), each being respectively drawn from one of the two supply lines (40a, 40b) and being configured to respectively supply one of the two control chambers (12a, 12b); two electrically calibratable pressure limiters (90a, 90b) respectively disposed on the two control lines (80a, 80b).

A work vehicle collective switch apparatus includes: a switch operation unit including a plurality of switches; a network side signal output unit that outputs a switch state signal to an in-vehicle network side connected to the collective switch apparatus; a drive signal output unit that outputs a drive signal to a direct-coupled device connected to the collective switch apparatus, and a control unit that outputs a command signal corresponding to switch operation on a basis of switch assignment information that assigns in advance as to whether the drive signal is to be output from the drive signal output unit or the switch state signal is to be output from the network side signal output unit in accordance with switch operation of any of the plurality of switches.

A series hydraulic hybrid driveline for a vehicle, having a hydraulic circuit with a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit, the first hydraulic displacement unit having a variable hydraulic displacement and the first hydraulic displacement unit being drivingly engaged with an internal combustion engine. A hydraulic accumulator assembly selectively fluidly connected to the hydraulic circuit, the hydraulic accumulator assembly having a high pressure hydraulic accumulator and a low pressure hydraulic accumulator. And a hydraulic actuator adapted to control the hydraulic displacement of the first hydraulic displacement unit, the hydraulic actuator being in fluid communication with the hydraulic accumulator assembly and/or with the hydraulic circuit. A method of shutting down an engine of a series hydraulic hybrid driveline and of re-starting the engine of a series hydraulic hybrid driveline using energy stored in a hydraulic accumulator assembly is also described.

A series hydraulic hybrid driveline for a vehicle, having a hydraulic circuit with a first hydraulic displacement unit in fluid communication with a second hydraulic displacement unit, the first hydraulic displacement unit having a variable hydraulic displacement and the first hydraulic displacement unit being drivingly engaged with an internal combustion engine. A hydraulic accumulator assembly selectively fluidly connected to the hydraulic circuit, the hydraulic accumulator assembly having a high pressure hydraulic accumulator and a low pressure hydraulic accumulator. And a hydraulic actuator adapted to control the hydraulic displacement of the first hydraulic displacement unit, the hydraulic actuator being in fluid communication with the hydraulic accumulator assembly and/or with the hydraulic circuit. A method of shutting down an engine of a series hydraulic hybrid driveline and of re-starting the engine of a series hydraulic hybrid driveline using energy stored in a hydraulic accumulator assembly is also described.

A work machine includes an engine, a pilot pump to be driven by the engine to supply a pilot fluid, an operation pump to receive a first pilot fluid to change an output power in accordance with the first pilot fluid, a pilot fluid tube provided between the pilot pump and the operation pump, an operation valve connected to the pilot fluid tube to output the first pilot fluid, the first pilot fluid being a part of the pilot fluid supplied from the pilot fluid, a temperature sensor to measure a temperature of at least one of an operation fluid including the pilot fluid, a cooling water, an engine oil, and an outside air, and a pressure controller to control a first pilot pressure of the pilot fluid outputted from the operation valve when a temperature measured by the temperature sensor is equal to or higher than a first temperature.

A work machine includes an engine, a pilot pump to be driven by the engine to supply a pilot fluid, an operation pump to receive a first pilot fluid to change an output power in accordance with the first pilot fluid, a pilot fluid tube provided between the pilot pump and the operation pump, an operation valve connected to the pilot fluid tube to output the first pilot fluid, the first pilot fluid being a part of the pilot fluid supplied from the pilot fluid, a temperature sensor to measure a temperature of at least one of an operation fluid including the pilot fluid, a cooling water, an engine oil, and an outside air, and a pressure controller to control a first pilot pressure of the pilot fluid outputted from the operation valve when a temperature measured by the temperature sensor is equal to or higher than a first temperature.

A drive, which permits a lowering in the feed pressure provided by the feed pump and, at the same time, effects a supply to the displacement unit of the drive which meets the demand with regard to pressure and delivery volume. This is achieved in that the displacement unit (5) is supplied with hydraulic energy by an electro-hydraulic supply unit (6) wherein the supply unit (6) comprises a hydraulic reservoir (9) and a non-return valve (18) and is connected to the feed pressure limiting valve (12), which is implemented as an electrically adjustable pressure limiting valve, wherein the hydraulic reservoir (9) is also connected to an electro-hydraulic pressure sensor (10), which outputs the electric signal thereof to an electric auxiliary controller (11), and wherein the electric auxiliary controller (11) drives the feed pressure limiting valve (12). These hydraulic drives are used for example, in self-propelled working machines.