In one or more embodiments, a system for predicting health of a hydraulic pump comprises a reservoir tank temperature sensor to measure a temperature of a reservoir tank. The system further comprises a hydraulic pump temperature sensor to measure a temperature of the hydraulic pump. Also, the system comprises a differential pressure sensor to measure a differential pressure across a filter associated with the hydraulic pump. Further, the system comprises a processor(s) to determine a differential temperature by subtracting the temperature of the reservoir tank from the temperature of the hydraulic pump, to compare the differential temperature to a differential temperature threshold, to compare the differential pressure to a differential pressure threshold, and to generate an alert signal indicating failure of the hydraulic pump, when the processor(s) determines that the differential temperature exceeds the differential temperature threshold and the differential pressure exceeds the differential pressure threshold.

A hydraulic drain system for a working machine including a hydrostatic pump, a tank, a cooler, a first conduit, and a second conduit. The hydrostatic pump is configured to be driven by a prime mover. The tank is configured to store fluid drained from the hydrostatic pump. The cooler is positioned upstream of the tank. The first conduit couples the hydrostatic pump to the cooler. The second conduit directly couples the hydrostatic pump to the tank.

The invention relates to a pressure oil filter system for a hydraulic transmission, in particular for a motor vehicle transmission, comprising at least one oil pump which can be actuated as required and which has a pressure side and a suction side, a pressure line to a consumer and at least a first oil filter which is arranged at the pressure side of the oil pump in the pressure line, wherein means for damping pressure surges during intermittent operation of the oil pump are provided in the pressure line upstream of the first oil filter in the flow direction of the oil.

An example valve includes: a plurality of ports comprising: (i) a first port, (ii) a second port configured to be fluidly coupled to a reservoir, and (iii) a third port configured to be fluidly coupled to a source of fluid; a spool slidably accommodated in a sleeve; an annular chamber formed between the spool and the sleeve, wherein the annular chamber is fluidly coupled to the first port, and wherein a first flow area is formed between the spool and the sleeve to fluidly couple the annular chamber to the second port via the first flow area; and a solenoid coil, wherein when the solenoid coil is energized, a solenoid force the spool, thereby causing the spool to move, forming a second flow area between the spool and the sleeve to fluidly couple the third port to the annular chamber via the second flow area.

A servohydraulic drive includes a hydrostatic displacement machine, an electric machine that is mechanically speed-coupled with the displacement machine, a hydraulic cylinder that is fluidically connected to the displacement machine via first and second working lines, a hydraulic accumulator, and a supply unit. The displacement machine has a stroke that is adjustable via a hydraulic adjustment device. The cylinder is configured to be activated by reversal of the fluid flow through the displacement machine in opposite directions. The accumulator is preset to a low pressure and is fluidically connected via a valve assembly in each case to the lower pressure working line. The supply unit is configured to supply the adjustment device with pressurized fluid under the necessary pressure for the adjustment regardless of the present pressure in the working lines such that the displacement machine is configured for an active and load pressure-independent adjustment of its stroke volume.

A liquid-pressure driving system includes: a pump connected to an actuator through two pressure liquid passages; pressurizing mechanisms interposed on the passages and applying pressure to the operating oil returning from the actuator; a low pressure selector valve connected to parts of the passages and introducing to a cooling passage the operating liquid having lower pressure between the operating liquids flowing through the two pressure liquid passages; a restrictor mechanism interposed on the cooling passage; a cooler apparatus interposed on the cooling passage downstream of the restrictor mechanism, the cooler apparatus cooling the operating liquid flowing through the cooling passage; and a pressure liquid returning mechanism connected to parts of the two pressure liquid passages, each of the parts being at one side of the corresponding pressurizing mechanism close to the pump, the pressure liquid returning mechanism returning the cooled operating liquid to the two pressure liquid passages.

A hydraulic motor apparatus includes a motor housing engaged to an end cap having a first porting system and an adapter connected to an external surface of the end cap and having a second porting system. A filter may be attached to the adapter and connected to the second porting system and a pressure reducing valve in the adapter is connected to the second porting system. The assembly may also include a controller operatively connected to the pressure reducing valve and system sensors measuring parameters affected by the output of the hydraulic motor apparatus, whereby the pressure reducing valve is operatively controlled by the controller in response to input from the system sensors.

A hydraulic drive unit includes: a pump; a pair of supply-discharge lines; a valve block; a sealed tank; a suction line that leads hydraulic oil in the sealed tank to the pump; a connecting line that connects an air vent port of the pump to the suction line; and a gas-liquid separator that separates air and the hydraulic oil flowing through the connecting line from each other. The pump is disposed upward of the valve block and the sealed tank in a vertical direction.

An example valve includes: a plurality of ports comprising: (i) a first port, (ii) a second port configured to be fluidly coupled to a reservoir, and (iii) a third port configured to be fluidly coupled to a source of fluid; a spool slidably accommodated in a sleeve; an annular chamber formed between the spool and the sleeve, wherein the annular chamber is fluidly coupled to the first port, and wherein a first flow area is formed between the spool and the sleeve to fluidly couple the annular chamber to the second port via the first flow area; and a solenoid coil, wherein when the solenoid coil is energized, a solenoid force the spool, thereby causing the spool to move, forming a second flow area between the spool and the sleeve to fluidly couple the third port to the annular chamber via the second flow area.

A control device for at least one hydraulic working section (A, B), which can be connected to a pressure supply source (P) and a return flow (T) via a hydraulic supply circuit and to a control valve (34) supplied with a pilot pressure. The device includes an emergency shutdown system (32) having a pilot solenoid valve (16) and an additional valve (14). Both the hydraulic energy flow from the pressure supply source (P) to at least one of the respective working sections (A, B) and the pilot pressure supply to the control valve (34) can be suppressed by the pilot solenoid valve (16) via the additional valve (14).