Komatsu Corporation

Yuusuke Miyamoto

Yuichi Hishinuma

Toyomi Kataoka

Keita Nagaoka

A hydraulic circuit includes: a direction switching valve, which is in a state where a bottom oil path is connected to a first tank oil path and where a bypass oil path is connected to a second tank oil path when a pump oil path is connected to a rod oil path and when the rod oil path is connected to the bypass oil path when the pump oil path is connected to the bottom oil path, and a pilot operation control valve which allows flows of oil in both directions between the direction switching valve and the bottom oil path when the pump oil path is connected to the rod oil path and allows only a flow of oil from the direction switching valve to the bottom oil path when the pump oil path is connected to the bottom oil path by the direction switching valve.

Hydraulic circuit

A valve device switching between an open position and a close position, the open position allowing passage of oil through a gap between two ports in a spool bore from a small-diameter portion of a spool via a notch formed in a large-diameter portion of the spool, the close position blocking passage of oil through the gap between the two ports by the large-diameter portion, wherein the notch of the large-diameter portion has an inner bottom face at a portion located on a center side of the spool and is open to an outer peripheral space of the small-diameter portion and an outer peripheral surface of the large-diameter portion, and is formed such that an opening width of an opening at the outer peripheral surface is larger than a width of the inner bottom face.

Growing community of inventors

Tokyo, Japan

Yuusuke Miyamoto