Independent displacement opposing pump/motors and method of operation
First Claim
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1. A hydraulic machine comprising:
- a first variable displacement hydraulic motor having a first displacement capacity and a first output to which the first motor is configured to apply a varying degree of torque according to a degree of displacement of the first motor;
a second variable displacement hydraulic motor having a second displacement capacity, and a second output to which the second motor is configured to apply a varying degree of torque according to a degree of displacement of the second motor;
an output shaft to which the outputs of the first and second motors are rigidly coupled at respective ends thereof such that the first and second outputs rotate at a common rate; and
a displacement control unit configured to control displacement of the first and second motors such that;
while the sum of the displacements of the first and second motors is below a first value, the machine operates in a first mode, in which the displacement of the first motor is substantially equal to the sum, and the displacement of the second motor is substantially equal to zero,if the sum of the displacements increases from below the first value to beyond the first value, without exceeding a second value, greater than the first value, the machine continues to operate in the first mode,if the sum of the displacements increases to beyond the second value, the machine operates in a second mode, andonce having increased beyond the second value, the machine does not return to operation in the first mode until the sum of the displacements drops below the first value.
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Abstract
A hydraulic machine includes first and second opposing motors. Displacement of the first and second motors is controlled such that while the sum of the displacements of the first and second motors is below a threshold, the displacement of the first motor is substantially equal to the sum, and the displacement of the second motor is substantially equal to zero. While the sum of the displacements is above the threshold, the displacement of the first motor may be substantially equal to the displacement of the second motor, either as a displacement percentage or as a displacement volume. The first motor may be equal in capacity, or smaller than the second motor.
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Citations
43 Claims
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1. A hydraulic machine comprising:
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a first variable displacement hydraulic motor having a first displacement capacity and a first output to which the first motor is configured to apply a varying degree of torque according to a degree of displacement of the first motor; a second variable displacement hydraulic motor having a second displacement capacity, and a second output to which the second motor is configured to apply a varying degree of torque according to a degree of displacement of the second motor; an output shaft to which the outputs of the first and second motors are rigidly coupled at respective ends thereof such that the first and second outputs rotate at a common rate; and a displacement control unit configured to control displacement of the first and second motors such that; while the sum of the displacements of the first and second motors is below a first value, the machine operates in a first mode, in which the displacement of the first motor is substantially equal to the sum, and the displacement of the second motor is substantially equal to zero, if the sum of the displacements increases from below the first value to beyond the first value, without exceeding a second value, greater than the first value, the machine continues to operate in the first mode, if the sum of the displacements increases to beyond the second value, the machine operates in a second mode, and once having increased beyond the second value, the machine does not return to operation in the first mode until the sum of the displacements drops below the first value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A hybrid vehicle system comprising:
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a drive machine having first and second opposing and rotationally coupled motors; and a control unit configured to independently control output torque of the first and second motors according to an operating range in which a total output torque of the machine falls, such that the first and second motors transition from a first mode of operation to a second mode of operation as the total output torque of the machine rises past a first threshold, and transition from the second mode of operation to the first mode of operation as the total output torque of the machine drops below a second threshold that is lower than the first threshold. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method comprising:
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varying an output torque of a first motor of a machine and maintaining a second motor of the machine, rotationally coupled to the first motor, at an output torque substantially equal to zero while a total output torque of the machine is within a first range; varying the output torque of the first motor of the machine and maintaining the second motor of the machine at an output torque substantially equal to zero while the total output torque of the machine is within a second range, greater than the first range, if the total output torque of the machine increases from the first range to the second range; varying the output torque of the second motor while the total output torque of the machine is within a third range, greater than the second range; and varying the output torque of the second motor while the total output torque of the machine is within the second range if the total output torque of the machine decreases from the third range to the second range. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. A hydraulic machine comprising:
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a first variable displacement hydraulic motor having a first displacement capacity and a first output to which the first motor is configured to apply a varying degree of torque according to a degree of displacement of the first motor; a second variable displacement hydraulic motor having a second displacement capacity, and a second output to which the second motor is configured to apply a varying degree of torque according to a degree of displacement of the second motor; an output shaft to which the outputs of the first and second motors are rigidly coupled at respective ends thereof such that the first and second outputs rotate at a common rate; and a displacement control unit configured to control displacement of the first and second motors such that while the sum of the displacements of the first and second motors is below a threshold value, the displacement of the first motor is substantially equal to the sum, and the displacement of the second motor is substantially equal to zero, and while the sum of the displacements of the first and second motors is above the threshold value, a displacement percentage of the first motor is substantially equal to a displacement percentage of the second motor.
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36. A hybrid vehicle system comprising:
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a drive machine having a first motor and a second motor, outputs of the first and second motors being rotationally coupled; and a control unit configured to independently control output torque of the first and second motors according to an operating range in which a total output torque of the machine falls, such that the output torque of the first motor is substantially equal to the total output torque of the machine and the output torque of the second motor is substantially equal to zero while the total output torque lies in a first range of operation, and the output torque percentage of the first motor is substantially equal to an output torque percentage of the second motor while the total output torque lies in a second range of operation. - View Dependent Claims (37)
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38. A method comprising:
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in a machine having a first motor with an output rotationally coupled to an output of the machine and a second motor with an output rotationally coupled to the output of the machine, varying an output torque of the first motor of the machine and maintaining the second motor of the machine at an output torque substantially equal to zero while a total output torque of the machine is within a first range; and varying output torque percentages of the first and second motors substantially equally while the total output torque of the machine is within a second range. - View Dependent Claims (39)
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40. A hybrid vehicle system comprising:
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a drive machine having first and second rotationally coupled motors; and a control unit configured to independently control output torque of the first and second motors according to an operating range in which a total output torque of the machine falls, such that; the first and second motors transition from a first mode of operation, in which the output torque of the first motor is substantially equal to the total output torque of the machine and the output torque of the second motor to be substantially equal to zero, to a second mode of operation, in which the output torque of the first motor is substantially equal to the output torque of the second motor, as the total output torque of the machine rises past a first threshold, and the first and second motors transition from the second mode of operation to the first mode of operation as the total output torque of the machine drops below a second threshold. - View Dependent Claims (41, 42, 43)
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Specification