Hydromechanical transmission and warm-up method
AssigneeDana Italia S.R.L.
InventorsGiacomo Faggiani, Mario Gelmini
Life of this patent
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Abstract
Methods and systems for a hydromechanical transmission are provided. In one example, the method includes responsive to rotation of a portion of a mechanical assembly induced by cranking of an engine, blocking an output shaft of the hydromechanical transmission via joint engagement of a forward drive clutch and a reverse drive clutch. The method further includes pressurizing a hydrostatic assembly while the forward drive clutch and the reverse drive clutch remain jointly engaged, where the mechanical assembly is coupled in parallel with the hydrostatic assembly.
Claims15
A hydromechanical variable transmission (HVT) comprising:
- a hydrostatic unit coupled in parallel with a mechanical branch;
- wherein the mechanical branch includes a first planetary gear set that is coupled to a forward drive clutch and a reverse drive clutch;
- a parking brake mechanism coupled to an output shaft;
- and
- a controller that comprises:
- instructions that when executed, during cranking of an engine coupled to the mechanical branch, cause the controller to:
- synchronously engage the forward drive clutch and the reverse drive clutch;
- and
- increase a pressure differential in the hydrostatic unit via adjustment of a displacement of a hydraulic pump in the hydrostatic unit;
- and
- instructions that when executed, subsequent to the synchronous engagement of the forward drive clutch and the reverse drive clutch, cause the controller to:
- disengage the parking brake mechanism.
A method for operation of a hydromechanical variable transmission (HVT), comprising:
- synchronously engaging a forward drive clutch and a reverse drive clutch;
- increasing a pressure differential in a hydrostatic unit via adjustment of a displacement of a hydraulic pump in the hydrostatic unit;
- and
- subsequent to the synchronous engagement of the forward drive clutch and the reverse drive clutch, disengaging a parking brake mechanism coupled to an output shaft;
- wherein the HVT includes:
- the hydrostatic unit coupled in parallel with a mechanical branch;
- wherein the mechanical branch includes a planetary gear set that is coupled to the forward drive clutch and the reverse drive clutch;
- and
- wherein the forward drive clutch and the reverse drive clutch are coaxially arranged.
A transmission system, comprising:
- a first planetary gear set;
- a hydrostatic assembly coupled in parallel with the first planetary gear set;
- a forward drive clutch and a reverse drive clutch coupled to the first planetary gear set and an output shaft;
- a parking brake mechanism coupled to the output shaft;
- and
- a controller comprising:
- instructions that when executed, while the first planetary gear set is receiving rotational input from a motive power source, cause the controller to:
- block the output shaft of the transmission system via joint engagement of the forward drive clutch and the reverse drive clutch;
- and
- pressurize the hydrostatic assembly while the forward drive clutch and the reverse drive clutch remain jointly engaged;
- and
- instructions that when executed, prior to the joint engagement of the forward drive clutch and the reverse drive clutch, cause the controller to:
- engage the parking brake mechanism;
- and
- instructions that when executed, subsequent to the joint engagement of the forward drive clutch and the reverse drive clutch, cause the controller to:
- disengage the parking brake mechanism.
Dependencies are inferred from the claim text.