A method for monitoring a fluid system for lubricating a mechanical system. The fluid system comprises a spraying circuit connected to a main fluid circuit and to a back-up fluid circuit. The back-up fluid circuit comprises a back-up check valve closed in a nominal operating mode. The method comprises a monitoring phase comprising the generation of a first alert in the presence of the detection of a malfunction making the main fluid circuit inoperative and the back-up check valve in an open state and the generation of a second alert different from the first alert in the presence a malfunction and the back-up check valve in a closed state.

A drive device has a superimposed transmission, an input shaft connected a main drive machine, one or more auxiliary drives, a hydrodynamic retarder for braking the auxiliary drive, and an output shaft to be connected to a working machine. The superimposed transmission has a planetary transmission, with the input shaft connected to a ring gear and the output shaft connected to a sun gear. The retarder is incorporated into a lubricating oil system of the drive device in parallel. A feed line branches from the lubricating oil system and leads to the retarder. A return line leads from the retarder and opens into the lubricating oil system. A valve enables the feed line to be released in the event of a rapid disconnection or energy supply failure of one of the drives, and thus the retarder can be filled with oil.

An automatic transmission has an oil pump driven by a travelling driving source. An air vent structure that expels air bubbles contained in automatic transmission fluid during pump operation has an air vent hole whose one end communicates with an outlet port of the oil pump and whose other end opens toward the oil pan. An air vent tube is connected to an opening end of the air vent hole. The air vent tube is extended up to a strainer lower side gap area located between a strainer and the oil pan, and a tube opening end of the air vent tube is placed in oil of the automatic transmission fluid.

An intermediate wall is provided with a return oil hole through which oil discharged from a friction engagement device returns toward an oil reservoir. A chain drive is disposed adjacent to the intermediate wall. The chain drive transmits a driving force from an input member and/or a rotary electric machine to an oil pump. There is provided an oil guide through which oil flowing through the return oil hole is guided to a region other than a chain placement region inside a case. The chain placement region is a region where a chain of the chain drive is placed.

A hydraulic arrangement for a vehicle transmission includes a hydraulic system path leading to a hydraulic system circuit with a system pressure, a hydraulic lubrication path leading to a hydraulic lubrication circuit with a lubrication pressure, and a branching point connected to an output side of the system and lubrication paths. A variable displacement pump or a pump combination includes at least two fixed displacement pumps hydraulically connected to an input side of the branching point, and a variable displacement pump or at least one fixed displacement pump are hydraulically connected to the output side of the branching point and integrated into the hydraulic system path.

A hydraulic gerotor pump for an automatic transmission may comprise a housing and a gear set rotatably disposed within the housing. The gear set may comprise an inner gear and an outer gear having radially opposed intermeshing teeth that together define a plurality of circumferentially disposed variable volume pumping chambers therebetween. The housing may be made of a first aluminum-based material, and the inner gear and the outer gear of the gear set may be made of a second aluminum-based material. The linear coefficient of thermal expansion of the first aluminum-based material may be substantially the same as that of the second aluminum-based material.

A hydraulic gearbox actuator with a hydraulic pump which has a pump body wherein a rotor is arranged, wherein a drive motor is provided with which the rotor can be driven in opposite directions, wherein two working chambers which are separated from each other are formed in the pump body, the working chambers each having two openings, of which at least three openings are connected to a respective pressure supply circuit, the one side of which is connected to a reservoir and the other side of which is connected to one of three pressure outlets of the gearbox actuator.

An electric oil pump system allows the cooling of an electric oil pump (EOP) and an oil pump controller (OPU) to be performed efficiently in the vehicle equipped with the electric oil pump. An electric oil pump of the system includes a pumping part that is operated by power of a motor to suction and direct pressurized oil. An oil pump controller operates the electric oil pump. A water-cooled cooling apparatus cools the oil pump controller using coolant and an oil-cooled cooling apparatus cools the electric oil pump using oil. The coolant of the water-cooled cooling apparatus and the oil of the oil-cooled cooling apparatus pass through a heat exchanger and as the coolant and oil pass therethrough, heat exchange is achieved.

An apparatus includes a heat exchanger, a power transmission mechanism, a lubricating oil passage that is located downstream of the heat exchanger and guides lubricating oil to the power transmission mechanism, and a drain oil passage that is located downstream of the heat exchanger and drains the lubricating oil.

A mechanical system comprising a sump and at least one component to be lubricated or cooled arranged in the sump, the mechanical system comprising a lubricating fluid system provided with a lubricating fluid and a tank arranged in the sump. The tank is a leaking tank and is situated above said at least one component to be lubricated or cooled, the lubricating fluid flowing out of the tank by force of gravity, so as to reach said at least one component to be lubricated or cooled. The lubricating fluid system has at least one lift flow generator connected by at least one filling line to the tank and to at least one suction point present in a bottom of the sump. The lift flow generator fills the tank with the lubricating fluid present in said bottom at least during a starting phase.