Hydromechanical transmissions having one-way devices to bridge efficiency discontinuities
First Claim
1. In a multirange hydromechanical transmission wherein shifting is accomplished by the release of gear element engaging means controlling one propulsion gear range and by the application of gear element engaging means controlling another gear range and wherein there is a discontinuity of output power and efficiency at the shift point between propulsion ranges with an excess of power in the lower range and less power in the higher range which is insufficient with respect to critical loads, the improvement comprising incorporation of a one-way element to provide self releasing gear reaction to bridge said discontinuity when running in the higher range under those critical loads.
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Accused Products
Abstract
An improved multirange synchronous shifting hydromechanical transmission wherein an overrunning clutch in parallel with the friction clutch of the lower gear range of two adjacent ranges is used to permit bridging the discontinuity in efficiency curves of the two ranges at the shift point to sustain operation under a load condition falling between the two efficiency curves and to prevent "hunting" during shifts between the two ranges.
31 Citations
19 Claims
- 1. In a multirange hydromechanical transmission wherein shifting is accomplished by the release of gear element engaging means controlling one propulsion gear range and by the application of gear element engaging means controlling another gear range and wherein there is a discontinuity of output power and efficiency at the shift point between propulsion ranges with an excess of power in the lower range and less power in the higher range which is insufficient with respect to critical loads, the improvement comprising incorporation of a one-way element to provide self releasing gear reaction to bridge said discontinuity when running in the higher range under those critical loads.
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8. In a multirange hydromechanical transmission including a hydrostatic component, at least one mechanical gear train component, a mixing and output drive train component, clutch means for alternately fixing and releasing elements of said components with respect to other moving or stationary elements to cause said components to be used in distinct combinations to constitute gear ranges, and means for operating said clutch means for fixing and releasing to cause said transmission to shift from one range to another, wherein two successive gear ranges employ said hydrostatic component under different hydraulic operating pressures and wherein, during operation at or near a shift point between said ranges in which said hydraulic operating pressure for the higher range is higher, a critical load can cause said hydrostatic component to operate in a less efficient mode in the higher range than the mode in which it operates in the lower range;
- the improvement comprising incorporation of a one-way device to limit operation of said hydrostatic component to operate in the more efficient mode.
- View Dependent Claims (9, 10, 11)
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12. In a synchronous shifting multirange hydromechanical transmission including
an input power train, an infinitely variable hydrostatic drive component driven by said input power train, at least one mechanical drive component driven by said input power train, an output power train including at least one power output connected to said drive components for receipt of power from each or combinations of said drive components, and clutch means for selectively fixing to and releasing elements of said components from other elements of said transmission whereby selective actuations of said clutch means to permit different combinations of said components to drive said output power train to cause said transmission to operate in a plurality of distinct ranges of different drive ratios, and wherein there is a discontinuity of output efficiency between two successive said ranges each utilizing the hydrostatic drive component with the higher speed range having the lesser efficiency, the improvement comprising a one-way device operatively connected to an element which is operative during transmission operation in said higher range to prevent said hydrostatic component from assuming a mode of operation in said higher range which is less efficient than its role in the lower range to bridge said discontinuity.
Specification