| 摘要 |
PROBLEM TO BE SOLVED: To provide an input torque control circuit for a variable displacement pump, for performing constant torque control by which a sudden change of the discharge amount of a pump can be prevented while effectively making use of engine output. SOLUTION: An input torque control circuit A' of a variable displacement pump is provided with a first constant torque control means S1 for performing constant torque control of a first pump 4 by discharge pressure of the first pump 4 and discharge pressure of a second pump 6, and a second constant torque control means S2 for performing constant torque control of the second pump 6 by only discharge pressure of the second pump 6, the first constant torque control means S1 holds discharge pressure of the second pump 6 in starting of constant torque control when constant torque control is started by the second constant torque control means S2, and constant torque control of the first pump 4 is performed by the held pressure and discharge pressure of the first pump 4. |
