Kyb Corporation

Kayaba Industry Company, Ltd.

Shunsuke Fukuda

Nobuyoshi Yoshida

Keiichi Matsuzaki

Ryo Fukushima

A valve device includes: a main spool including supply passages and a supply-side land portion; and a valve block including an outflow passage, in which the supply passage allows a supply port to communicate with the outflow passage in a process of the main spool moving from a neutral position toward one stroke end in an axial direction, and the supply passage allows a supply port to communicate with the outflow passage in a process of the main spool moving from the neutral position toward the other stroke end in the axial direction, and the supply passage allows the supply port to communicate with the outflow passage in the process of the main spool moving toward the one stroke end and allows the supply port to communicate with the outflow passage in the process of the main spool moving toward the other stroke end.

Valve device

A fluid pressure control device includes a first switching valve provided on a downstream of a first travel control valve in the first main passage and having an open position and a priority position, a second switching valve provided on a downstream of a second travel control valve in the second main passage and having an open position and a priority position, and a merging passage connecting a downstream of the first switching valve and a downstream of the second switching valve. In a state where first work control valves and second work control valves are not operated and the first travel control valve is operated, the first switching valve is at a priority position, and in a state where the first work control valves and the second work control valves are not operated and the second travel control valves is operated, the second switching valve is at a priority position.

Fluid pressure control device

A fluid pressure control device for a construction machine includes a first circuit system connected to the first pump; a second circuit system connected to the second pump; a switching valve having a normal position, a straight traveling position and a merging position where the working fluid of the branch section is merged into the second neutral passage; and an open/close mechanism configured to open/close the first neutral passage. In a case where at least one of the control valves, on which merging is required, on the downstream of the second traveling control valve is switched to a position other than the neutral position, by closing the first neutral passage by the open/close mechanism and switching the switching valve to the merging position, the working fluid of the first pump is merged into the working fluid of the second pump.

Fluid pressure control device for construction machine

A control system for a hybrid construction machine includes first and second main pumps, first and second supply passages, first and second circuit systems, a hydraulic motor, a motor generator, an assist pump, a joint passage connected to the assist pump and branching off, first and second logic valves, and a switching valve. The switching valve switches between a state where the assist pump is connected to the second supply passage and a state where the second main pump is connected to the hydraulic motor. A bypass passage branches off from the other branch passage at the downstream of the switching valve. The bypass passage is connected to the second supply passage on the downstream side of the second logic valve.

Control system for a hybrid construction machine

A hybrid construction machine includes first and second main pumps, first and second supply passages, first and second circuit systems, a hydraulic motor, a motor generator, an assist pump, a joint passage connected to the assist pump and branched off, first and second logic valves, a switching valve disposed in the other branch passage and switchable to a state where the assist pump is connected to the second supply passage on the upstream side of the second logic valve and a state where the second main pump is connected to the hydraulic motor, and a check valve. A poppet diameter of the first logic valve is smaller than that of the second logic valve.

Hybrid construction machine

A circuit pressure control unit includes a relief valve and a variable throttle valve. The relief valve is connected to a connecting passage communicating with an actuator upstream. The variable throttle valve is disposed upstream of the relief valve and is configured to change an opening degree thereof according to a control signal from a controller.

Growing community of inventors

Kanagawa, Japan

Shunsuke Fukuda