Measuring and testing – Simulating operating condition – Marine
Patent
1992-06-01
1994-09-20
Raevis, Robert
Measuring and testing
Simulating operating condition
Marine
G01M 1500
Patent
active
053478576
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates generally to an apparatus and method for detecting and measuring the phase difference between two rotatable shafts, and more particularly, to an apparatus and method for controllably detecting and measuring the dynamic phase difference between a driving and driven rotatable shaft.
2. Background Art
It is frequently necessary to couple driving and driven members of a machine assembly to one another. The coupling element in such situations is generally flexible in order to account for slight misalignment between shafts. An exemplary instance of such a machine is a stationary reciprocating engine coupled to a torque converter, transmission, electric generator or the like. In such cases, the technique of utilizing a flexible coupler to connect the two rotating shafts provides efficient transmission of mechanical power while compensating for axial movement and angular misalignment of the shafts.
In such an arrangement, engine misfire, governor instability, or other disturbances can cause an increase in the dynamic deflection of the flexible coupler. These oscillations or torsionals between the engine and the externally mounted inertia of the load can cause failure of the flexible coupler when the amplitude of the oscillation becomes great enough.
While it is desirable to minimize the torsionals affecting the operation of a machine having driving and driven members, some oscillations cannot be eliminated. Things such as engine misfires, engine loading, torque reversals, engine start-up, etc. are bound to occur. Therefore, in order to prevent failure of the flexible coupler, it is desirable to sense an oscillating condition before the amplitude of the oscillations becomes great enough to cause failure. Once sensed, action can be taken to stop the engine or otherwise reduce the possibility that failure will occur.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, an apparatus associated with driving and driven members of a machine assembly is provided. Each member has an associated rotatable shaft, the shafts being interconnected by a coupling element. The rotational phase differences between the driving and driven rotatable shafts are detected and measured. These phase differences are compared with a reference phase difference and an error signal is produced in response to the measured phase difference exceeding the reference level.
In a second aspect of the present invention, a method for detecting phase differences is provided. An apparatus associated with driving and driven members of a machine assembly, each member having an associated rotatable shaft connected to another shaft by a coupling element, is provided. The method includes the steps of detecting and measuring rotational phase differences between the driving and driven shafts, comparing the measured phase differences with a reference phase difference level, and producing an error signal in response to the measured phase difference exceeding the reference level.
The present invention provides a phase detection apparatus and method that is both simple and accurate and that can determine and react to a phase difference that might be destructive to the coupling member.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, reference may be made to the accompanying drawings, in which:
FIG. 1 is a diagrammatic view of an engine having a gear toothed flywheel member attached by a flexible coupling to a load;
FIG. 2 is a graphical representation of the phase shift occurring between the engine shaft and the load shaft of an arrangement such as found in FIG. 1;
FIG. 3 is a block diagram embodiment of the present invention;
FIG. 4 is a graphical representation of the output of transducers associated with an embodiment of the present invention; and
FIGS. 5 through 7 are functional flowcharts of computer software used with an embodiment of the present inventio
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Earleson Walter E.
Mirhakimi Siamak
Ohlson Eric W.
Caterpillar Inc.
Raevis Robert
Wilbur R. Carl
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