MACHINE TOOL AND MOTOR PUMP UNIT

PROBLEM TO BE SOLVED: To provide a motor pump unit capable of achieving a maximum compact shape of the motor pump unit, improving energy efficiency of an entire system, and ensuring high trouble resistance of a functional component.SOLUTION: In the machine tool having a functional component hydraulically operated, a pressure pipe path provided by a motor pump unit is divided into a high-pressure section and a low-pressure section by a pressure reduction valve, and an accumulator 8 and a pressure switch 7 are connected to the high-pressure section. The pressure reduction valve is a 3-port valve of a seat valve design, connected to a return pipe path 11 at the second outlet 16 of the pressure reduction valve. The pressure switch is set to an upper limit switch-off threshold value roughly corresponding to a pressure level in the high-pressure section and a lower limit switch-on threshold value at least corresponding to 1.5 times of a pressure level in the low-pressure section. The accumulator is subjected to pretension corresponding to the pressure level in the low-pressure section, and has an oil capacity to mainly operate the functional component from the accumulator.