Hydraulic excavator

摘要

In a hydraulic excavator, a hydraulic cylinder drives a boom via a hydraulic fluid discharged from a first hydraulic pump. A first hydraulic circuit connects the first hydraulic pump and the hydraulic cylinder and forms a closed circuit therebetween. A hydraulic motor rotates a revolving upper unit with hydraulic fluid discharged from a second hydraulic pump. A second hydraulic circuit independent from the first hydraulic circuit connects the second hydraulic pump and the hydraulic motor. A motor hydraulic pressure reduction unit reduces the driving hydraulic pressure of the hydraulic motor when a predetermined condition is satisfied. The predetermined condition is a condition in which an operation of the boom operating member to raise the boom and an operation of the rotation operating member to rotate the revolving upper unit are conducted together and an operation amount of the boom operating member is equal to or greater than a predetermined threshold.

主权项

1. A hydraulic excavator comprising:
an undercarriage; a revolving upper unit disposed on the undercarriage, the revolving upper unit being configured to rotate with respect to the undercarriage; a working implement including a boom pivotably attached to the revolving upper unit; a first hydraulic pump configured to discharge hydraulic fluid; a hydraulic cylinder configured to drive the boom with hydraulic fluid discharged from the first hydraulic pump; a first hydraulic circuit connecting the first hydraulic pump and the hydraulic cylinder, the first hydraulic circuit forming a closed circuit between the first hydraulic pump and the hydraulic cylinder; a second hydraulic pump configured to discharge hydraulic fluid; a hydraulic motor configured to rotate the revolving upper unit with hydraulic fluid discharged from the second hydraulic pump; a second hydraulic circuit provided independently of the first hydraulic circuit, the second hydraulic circuit connecting the second hydraulic pump and the hydraulic motor; a boom operating member configured to operate the boom; a rotation operating member configured to operate a rotation of the revolving upper unit; and a motor hydraulic pressure reduction unit configured to reduce a driving hydraulic pressure of the hydraulic motor when a predetermined condition is satisfied, the predetermined condition being a condition in which
an operation of the boom operating member to raise the boom and an operation of the rotation operating member to rotate the revolving upper unit are conducted together andan operation amount of the boom operating member is equal to or greater than a predetermined threshold.