Doosan Infracore Co., Ltd.

Ki Hwan Hong

Byung Il Kang

Keun Chul Song

Sang Beom Kim

Chung Rae Lee

Dae Gyun Choi

Hee Seog Kong

The present disclosure relates to a closed circuit hydraulic system for a construction machine including a plurality of actuators and a plurality of hydraulic pumps selectively supplying working oil to the plurality of actuators bidirectionally and the closed circuit hydraulic system includes: a charge line selectively connected with a low-pressure side hydraulic line which returns to the hydraulic pump from the actuator among hydraulic lines connecting the hydraulic pumps and the actuators; a charge pump supplying a supplement flow to the charge line; and a variable relief valve selectively changing a normal mode to limit a pressure of the charge line to a predetermined pressure or less and a boost mode to limit the pressure of the charge line to a pressure lower than the pressure of the charge line in the normal mode.

Closed-circuit hydraulic system for construction machine

A pilot signal block assembly includes at least two base blocks arranged to be spaced apart from each other in a first direction and having a plurality of receiving holes configured to move a spool therein in one direction, a plurality of cartridge blocks arranged on a surface of the base block to be spaced apart from each other in a second direction, each of the cartridge blocks including a signal passage which is in fluid communication with the corresponding receiving hole to supply a pilot oil to the corresponding receiving hole, and a plurality of electro proportional pressure reducing valves installed in the cartridge blocks respectively and controlling an opening rate of the signal passage in proportional to an electric control signal.

Pilot signal block assembly for construction machinery and control valve assembly having the same

The present disclosure relates to a hybrid excavator boom actuating system and to a method for controlling the same. The boom actuating system comprises: an electric motor serving as a motor or a generator; an ultra capacitor for storing electricity generated by the electric motor; a hydraulic pump motor driven by the electric motor to supply hydraulic fluid to a boom; a boom control valve which has a closed circuit for selectively connecting or disconnecting an outlet line and an inlet line of the hydraulic pump motor to or from a head or a rod side of the boom; a main pump driven by the engine to supply hydraulic fluid to a bucket, a travel motor or an arm; a motor bypass valve connected to the outlet line and the inlet line to interconnect the outlet line and the inlet line or disconnect the outlet line from the inlet line; and a controller for controlling the electric motor, the hydraulic pump motor, the boom control valve and the motor bypass valve.

Hybrid excavator boom actuating system and method for controlling same

The present invention relates to a sliding bearing including a lubricating oil storing unit storing lubricating oil on the surface thereof and the sliding bearing of the present invention is provided so that the volume of the lubricating oil storing unit occupies 5 to 30 volume % of the entire volume of the sliding bearing.

Growing community of inventors

Incheon, South Korea

Ki Hwan Hong