Hydraulically actuated continuously variable transmission for a vehicular drive line provided with an internal combustion engine
AssigneeRobert Bosch GmbH
InventorFrancis Maria Antonius VAN DER SLUIS
Life of this patent
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Abstract
A hydraulically actuated continuously variable transmission (1) is provided with a hydraulic system (TH) for the control of the torque transmissible by the transmission (1) as well as the speed ratio provided by the transmission (1). The hydraulic system (TH) is provided with a mechanically driven hydraulic pump (PM) and with an electrically driven hydraulic pump (PE) for generating a pressurised flow of hydraulic medium for the actuation of the transmission. The electrically driven pump (PE) can be switched either downstream of or in parallel with the mechanically driven pump (PM).
Claims13
Continuously variable transmission (1) for transmitting a drive power between an engine (IC) and a load (L) at a variable transmission ratio, in particular in a drive line of a vehicle, provided with a hydraulic system (TH) for the control of a hydraulic pressure in at least two parts of the hydraulic system (TH), being an actuation pressure (Pact) in a main actuation line (20) en an auxiliary pressure in a distribution line (11), with a first pump (PM) that is mechanically driven, in particular by the engine (IC), for pumping hydraulic fluid from a reservoir (10) to the distribution line (11), with a second pump (PE) that is electrically driven for pumping hydraulic fluid from an inlet (39) thereof to the main actuation line (20) and with a switch valve (36) for selectively providing a hydraulic connection between the inlet (39) of the electrically driven pump (PE) and either the distribution channel (11) or the reservoir (10), wherein the hydraulic system (TH) comprises connecting means (36) that effect a hydraulic connection (37) between the main actuation line (11) and the distribution line (11), if the inlet (39) of the electrically driven pump (PE) is connected to the reservoir (10), and that do not effect such hydraulic connection (37), if the inlet (39) of the electrically driven pump (PE) is connected to the distribution line (11).
Dependencies are inferred from the claim text.