CONSTRUCTION MACHINE

摘要

A construction machine is provided which is capable of warming up without an additional hydraulic device. A hydraulic excavator includes a cooling oil line connected to an arm control valve for leading hydraulic oil discharged from the arm control valve to a tank through an oil cooler when the arm control valve is shifted to an extension position, and a non-cooling oil line connected to the arm control valve for leading hydraulic fluid discharged from the arm control valve to the tank running away from the oil cooler when the arm control valve is shifted to a neutral position. The arm control valve includes a guide passage provided at the neutral position for leading hydraulic fluid discharged from a hydraulic pump to the non-cooling oil line.

主权项

1. A construction machine, comprising:
a hydraulic pump for discharging hydraulic fluid; a hydraulic actuator to be operated by hydraulic fluid discharged from the hydraulic pump; a tank for receiving hydraulic fluid discharged from the hydraulic actuator; a control valve shiftable between a permitting position to permit supply of hydraulic fluid from the hydraulic pump to the hydraulic actuator and discharge of hydraulic fluid from the hydraulic actuator to the tank and a restricting position to restrict the supply and the discharge of hydraulic fluid; a cooling oil line including an oil cooler for cooling hydraulic fluid, and being connected to the control valve for leading hydraulic oil discharged from the control valve to the tank through the oil cooler when the control valve is shifted to the permitting position; and a non-cooling oil line connected to the control valve for leading hydraulic oil discharged from the control valve to the tank running away from the oil cooler when the control valve is shifted to the restricting position, wherein the control valve includes a guide passage provided at the restricting position for allowing hydraulic oil discharged from the hydraulic pump to flow to the non-cooling oil line.