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US 5,730,678 AGranted
Multi-range, hydromechanical transmission for motor vehicles
OwnerRobert Francis Larkininventor
Life of this patent
Estimating the term…
Abstract
A hydromechanical transmission receives split power inputs from a vehicle engine, one split input driving a hydrostatic power unit and the other split input driving a mechanical power input. The infinitely variable hydrostatic power output is combined in the mechanical power unit with multiple ratios of its split input power to achieve multiple ratios of hydromechanical output power for smoothly propelling a vehicle from rest through multiple transmission ranges to maximum speed, with synchronous shifting between ranges.
Claims23
A vehicular multi-range hydromechanical transmission comprising, in combination:
- a transmission controller for receiving operator speed commands;
- a hydrostatic power unit having a first mechanical input for driving connection to a prime mover and a unidirectional hydrostatic output, the hydrostatic power unit operatively connected for control by the transmission controller to provide an infinitely variable transmission ratio between a speed of the first mechanical input and a speed of the hydrostatic output over a continuous range of 1:0 to 1:1;
- and
- a mechanical power unit having a second mechanical input for driving connection to the prime mover and a transmission output for connection to a load, the mechanical power unit including:
- a first planetary gear set having a first gear element connected to the second mechanical input at a first gear ratio, and second and third gear elements;
- a combining gear mechanism including second and third interconnected planetary gear sets having a fourth gear element connected to the third gear element of the first planetary get set, a fifth gear element connected to the hydrostatic output, a sixth gear element connectable to the second mechanical input at a second gear ratio, and a seventh gear element connected as the transmission output;
- and
- range shifting means actuated by the transmission controller in response to the operator input speed command for braking and/or clutching selected gear elements of the first, second, and third planetary get sets to produce an infinitely variable output speed at the transmission output within each of at least one reverse range and at least first, second, and third forward ranges.
5 more elements
A vehicular multi-range hydromechanical transmission, comprising, in combination:
- a transmission controller for receiving operator input commands;
- a hydrostatic power unit having a first input shaft for connection to a vehicle engine and a first output shaft, the hydrostatic transmission operatively connected to the transmission controller for producing an infinitely variable transmission ratio between a speed of the first input shaft and a speed of a hydrostatic output on the first output shaft over a continuous range of 1:0 to 1:1;
- and
- a mechanical power unit having a second input shaft for driving connection to the prime mover and a second output shaft for connection to deliver output power to at least one vehicle driving wheel, the mechanical power unit including:
- a first planetary gear set having a first gear element connected to the second input shaft at a first gear ratio, and second and third gear elements;
- a second planetary gear set having a fourth gear element connected to the second gear element of the first planetary gear set, and fifth and sixth gear elements;
- a combining gear mechanism including third and fourth planetary gear sets having a seventh gear element connected to receive the hydrostatic output on the first output shaft, an eighth gear element connected to the fifth gear element of the second planetary gear set, a ninth gear element connected to the second output shaft, a tenth gear element connectable to the second and third gear elements of the first planetary gear set at a second gear ratio, an eleventh gear element connected in common with the ninth gear element and the second output shaft, and a twelfth gear element connected in common with the eight gear element and the fifth gear element of the second planetary gear set;
- and
- range-shifting means actuated by the transmission controller in response to operator input commands for braking and/or clutching selected first to twelfth gear elements of the first to fourth planetary gear sets to produce infinitely variable output speeds on the second output shaft in each of a plurality of forward speed ranges and each of a corresponding plurality of reverse speed ranges, the corresponding pluralities of forward and reverse speed ranges being separated by a transmission neutral.
6 more elements
Dependencies are inferred from the claim text.