A transfer pump configured to move a hydraulic fluid in a hydraulic fluid management system of a hydraulic system of a vehicle including a transmission. In one embodiment, the transfer pump moves the fluid from a differential case to a hydraulic reservoir coupled to the transmission. The transfer pump is a positive displacement pump including an unloading device, such as a sealing plate, that is resiliently biased against the pump during a normal operation but is moved away from the pump upon the application of a pilot pressure. The result is an open chamber for the pump gears to turn without developing pressure, to thereby reduce parasitic losses.

A hydrostatic transmission which utilizes a combination of a multiple planetary gear pump and a multiple planetary gear motor encased within one compact unit sealed so as to direct passage of hydraulic fluid between the combination thereof. The hydrostatic transmission comprises a power component provided with a plurality of planetary gears that can provide power to at least one load delivered by at least one of the plurality of planetary gears. The power component is configured with an integrated oil-switching mechanism that controls the rotational speed delivered to the load. The hydrostatic transmission is provided in one compact, sealed casing suitable for use in vehicles, having an output shaft optionally mechanically connected directly to the wheels of a vehicle drive. The inventive hydrostatic transmission operates without the need for lengthy pressure hoses and related connectors and fittings for cycling hydraulic fluid along needed flow paths.

The invention relates to a downhole tool for use in a petroleum well. The downhole tool (100) comprises a first part (110) comprising a driving unit (8), and second part (120) comprising a driven unit (9), wherein the drive unit (8) is configured for driving the driven unit (9). The downhole tool (100) comprises a coupling unit (1) having an input side (S1) coupled with the driving unit (8) and an output side (S2) coupled with the driven unit (9), wherein the driving unit (8) is configured for driving the driving unit (9) via the coupling unit (1) comprising a torque limiting coupling having a first operational mode, the coupling unit (1) transfers all torque from the input side (S1) to the output side (S2), the coupling unit (1) further having a second operational mode, wherein the coupling unit (1) slips such that less torque is transferred form the input side (S1) to the output side (S2), wherein the second operational mode is automatically activated when the torque load on the input side exceeds a predefined level, and wherein the first operational mode is automatically activated when the torque load on the input side reduces to a level below a further predefined level. The coupling unit (1) comprises a displacement pump (2), wherein the displacement pump (2) is activated by opening of a pressure-limitation valve (4), for facilitating slipping of the coupling unit (1) when the coupling unit (1) is switching to the second operational mode, and wherein the displacement pump (2) is deactivated by closing of the pressure-limitation valve (4), for locking the coupling unit (1) when the coupling unit (1) is switching to the first operational mode.

The invention relates to a downhole tool for use in a petroleum well. The downhole tool (100) comprises a first part (110) comprising a driving unit (8), and second part (120) comprising a driven unit (9), wherein the drive unit (8) is configured for driving the driven unit (9). The downhole tool (100) comprises a coupling unit (1) having an input side (S1) coupled with the driving unit (8) and an output side (S2) coupled with the driven unit (9), wherein the driving unit (8) is configured for driving the driving unit (9) via the coupling unit (1) comprising a torque limiting coupling having a first operational mode, the coupling unit (1) transfers all torque from the input side (S1) to the output side (S2), the coupling unit (1) further having a second operational mode, wherein the coupling unit (1) slips such that less torque is transferred form the input side (S1) to the output side (S2), wherein the second operational mode is automatically activated when the torque load on the input side exceeds a predefined level, and wherein the first operational mode is automatically activated when the torque load on the input side reduces to a level below a further predefined level. The coupling unit (1) comprises a displacement pump (2), wherein the displacement pump (2) is activated by opening of a pressure-limitation valve (4), for facilitating slipping of the coupling unit (1) when the coupling unit (1) is switching to the second operational mode, and wherein the displacement pump (2) is deactivated by closing of the pressure-limitation valve (4), for locking the coupling unit (1) when the coupling unit (1) is switching to the first operational mode.

A hydrostatic transmission which utilizes a combination of a multiple planetary gear pump and a multiple planetary gear motor encased within one compact unit sealed so as to direct passage of hydraulic fluid between the combination thereof. The hydrostatic transmission comprises a power component provided with a plurality of planetary gears that can provide power to at least one load delivered by at least one of the plurality of planetary gears. The power component is configured with an integrated oil-switching mechanism that controls the rotational speed delivered to the load. The hydrostatic transmission is provided in one compact, sealed casing suitable for use in vehicles, having an output shaft optionally mechanically connected directly to the wheels of a vehicle drive. The inventive hydrostatic transmission operates without the need for lengthy pressure hoses and related connectors and fittings for cycling hydraulic fluid along needed flow paths.

A method and system are provided for controlling the operating temperature of a torque converter during torque converter stall conditions. The torque converter has a pump rotatably driven by an internal combustion engine and a rotatable turbine fluidly coupled to the pump. The system first determines whether the torque converter is currently in a torque converter stall condition, and, if so, determines a slip speed as a difference in rotational speeds between the pump and the turbine, determines an engine output torque limit as a function of the slip speed and a desired slip speed, and controls the operating temperature of the torque converter by limiting output torque produced by the engine based on the engine output torque limit.

A method and system are provided for controlling the operating temperature of a torque converter during torque converter stall conditions. The torque converter has a pump rotatably driven by an internal combustion engine and a rotatable turbine fluidly coupled to the pump. The system first determines whether the torque converter is currently in a torque converter stall condition, and, if so, determines a slip speed as a difference in rotational speeds between the pump and the turbine, determines an engine output torque limit as a function of the slip speed and a desired slip speed, and controls the operating temperature of the torque converter by limiting output torque produced by the engine based on the engine output torque limit.