Kyb Corporation

Kayaba Industry Company, Ltd.

Canon Kabushiki Kaisha

Nobuyoshi Yoshida

Masaki Ojima

Yoshihiro Mitsui

Satoru Inami

Yuichiro Hirata

Kodai Hayashi

Masahito Kato

Shinya Yamamoto

Tadashi Dojo

Shunsuke Fukuda

Ikuo Inagaki

Takeshi Terao

Toshiyuki Kitani

Atsushi Fujii

Yoshikazu Ogaya

A valve device includes a relief valve configured to be opened when a pressure in a fluid pressure circuit reaches a predetermined pressure and to relieve a working fluid, a tank passage connected to a tank, a main relief passage connecting the relief valve and the tank passage, and a sub relief passage branching from the main relief passage and connected to the tank passage separately from the main relief passage.

Valve device

A cap with electromagnetic proportional valve, includes a pilot cap mounted on a valve housing and defining a pilot chamber, and an electromagnetic proportional valve mounted on the pilot cap and adapted to control a pressure of a working fluid supplied to the pilot chamber. The pilot cap includes a supply port into which a working fluid of a fluid pressure supply source is supplied, a discharge port from which the working fluid is discharged to the tank, a primary pressure passage which leads the working fluid at a primary pressure to the electromagnetic proportional valve from the supply port, a secondary pressure passage which leads the working fluid whose pressure is reduced to a secondary pressure by the electromagnetic proportional valve to the pilot chamber, and a drain passage which leads the working fluid discharged from the electromagnetic proportional valve to the discharge port.

Cap with electromagnetic proportional valve

A working machine control system includes a split flow type fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port, and a lower pressure selection circuit configured to select and communicate with a working fluid of lower pressure among a working fluid on the downstream of a first operation valve of a first neutral passage in a first circuit system to which a working fluid discharged from the first discharge port is supplied, and a working fluid on the downstream of a second operation valve of a second neutral passage in a second circuit system to which a working fluid discharged from the second discharge port is supplied. The fluid pressure pump is adjusted in such a manner that the lower the pressure of the working fluid selected by the lower pressure selection circuit is, the more a discharge flow rate is increased.

Working machine control system and lower pressure selection circuit

A working machine control system includes: a split-flow fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port; a communication switching valve configured to allow, when one of a first operation valve and a second operation valve is switched, the first discharge port or the second discharge port for one of the first operation valve and the second operation valve that is not switched to communicate with a first neutral passage or a second neutral passage for the other of the first operation valve and the second operation valve that is switched; and a discharge flow rate adjusting device configured to adjust the fluid pressure pump so as to reduce a discharge flow rate of the fluid pressure pump in a case where a switch signal is inputted from any one of the first operation valve and the second operation valve.

Working machine control system

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 working machine control system includes: a split-flow fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port; a communication switching valve configured to be switched by a switch signal when any one of a first operation valve and a second operation valve is switched so as to allow a first neutral passage and a second neutral passage to communicate with each other; a neutral cut valve configured to be switched by the switch signal so as to block communication between a tank and one of the first neutral passage and the second neutral passage for the first operation valve or the second operation valve that is not switched; and a discharge flow rate adjusting device configured to adjust the fluid pressure pump so as to reduce a discharge flow rate thereof when the switch signal is inputted from any one of the first operation valve and the second operation valve.

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.

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Tokyo, Japan

Nobuyoshi Yoshida