Abstract: A fluid control device provided with a plurality of switching valves and a plurality of relief valves. A sub-relief passage communicating with a tank when the switching valves are in any state other than neutral is branched from a parallel passage for guiding a high-pressure hydraulic fluid to the switching valves. A sub-relief valve is provided within the sub-relief passage, and a check valve that minimizes the flow of hydraulic fluid toward a hydraulic pressure supply source is provided between switching valves and the point of branching of the sub-relief passage in the parallel passage.

Abstract: A fluid control device provided with a plurality of switching valves and a plurality of relief valves. A sub-relief passage communicating with a tank when the switching valves are in any state other than neutral is branched from a parallel passage for guiding a high-pressure hydraulic fluid to the switching valves.

Abstract: A pressure control valve includes a main valve unit provided with a main valve element and a valve housing body having a main valve seat capable of seating the main valve element and having a pilot chamber for slidably housing the main valve element. A pilot valve unit is provided with a pilot valve element and a pilot valve seat member has a pilot valve seat capable of seating the pilot valve element and separating the pilot valve element from the pilot valve seat and opening when a pressure in the pilot chamber exceeds a predetermined pressure. The pressure control valve is configured with recessed (concaved) parts that form hydraulic fluid channels between the pilot valve seat member and the pilot valve element when the pilot valve unit is in an open-valve-state at three or more locations so as to be separated by equal angles. Each recess has the same shape.

Abstract: A pressure control valve capable of preventing or suppressing the occurrence of the flaw that a pilot valve element which receives hydraulic pressure from a hydraulic fluid vibrates and hits a pilot valve seat member producing strange noise when the pilot valve element is in an opening state without resulting in an increase in number of components and assembling man-hours, the pressure control valve is provided with a main valve part containing a main valve element and a valve housing that includes a main valve seat on which the main valve element is able to be seated and a pilot chamber in which the main valve element is put in a slidable manner, and a pilot valve part containing a pilot valve element and a pilot valve seat member that includes a pilot valve seat on which the pilot valve element is able to be seated, the pilot valve element moving apart from the pilot valve seat to open when pressure in the pilot chamber exceeds a predetermined pressure.

Abstract: A pressure control valve capable of preventing or suppressing the occurrence of the flaw that a pilot valve element which receives hydraulic pressure from a hydraulic fluid vibrates and hits a pilot valve seat member producing strange noise when the pilot valve element is in an opening state without resulting in an increase in number of components and assembling man-hours, the pressure control valve is provided with a main valve part containing a main valve element and a valve housing that includes a main valve seat on which the main valve element is able to be seated and a pilot chamber in which the main valve element is put in a slidable manner, and a pilot valve part containing a pilot valve element and a pilot valve seat member that includes a pilot valve seat on which the pilot valve element is able to be seated, the pilot valve element moving apart from the pilot valve seat to open when pressure in the pilot chamber exceeds a predetermined pressure.

Abstract: A pressure control valve includes a main valve unit provided with a main valve element and a valve housing body having a main valve seat capable of seating the main valve element and having a pilot chamber for slidably housing the main valve element. A pilot valve unit is provided with a pilot valve element and a pilot valve seat member has a pilot valve seat capable of seating the pilot valve element and separating the pilot valve element from the pilot valve seat and opening when a pressure in the pilot chamber exceeds a predetermined pressure. The pressure control valve is configured with recessed (concaved) parts that form hydraulic fluid channels between the pilot valve seat member and the pilot valve element when the pilot valve unit is in an open-valve-state at three or more locations so as to be separated by equal angles. Each recess has the same shape.

Abstract: In a pressure compensation type flow rate control valve, overshoot of a flow rate when an upstream pressure is abruptly increased is suppressed. A first variable orifice 11 is provided on the side of an inflow opening and a second variable orifice 15 is provided on the side of an outflow opening. As the spool 3 is displaced from its initial position by a pressure of fluid entering when the upstream fluid pressure is increased, the opening of the first variable orifice 11 is gradually reduced, and the opening of the second variable orifice 15 is gradually increased. Since the second variable orifice 15 on the side of the outflow opening is previously reduced, even if the upstream pressure is abruptly increased, fluid more than a predetermined amount does not flow out toward the downstream.

Abstract: In a pressure compensation type flow rate control valve, overshoot of a flow rate when an upstream pressure is abruptly increased is suppressed. A first variable orifice 11 is provided on the side of an inflow opening and a second variable orifice 15 is provided on the side of an outflow opening. As the spool 3 is displaced from its initial position by a pressure of fluid entering when the upstream fluid pressure is increased, the opening of the first variable orifice 11 is gradually reduced, and the opening of the second variable orifice 15 is gradually increased. Since the second variable orifice 15 on the side of the outflow opening is previously reduced, even if the upstream pressure is abruptly increased, fluid more than a predetermined amount does not flow out toward the downstream.

Abstract: In a flow control valve, a spool is fitted into a cylindrical body including an input port and an output port. A spring is disposed between the spool and a flow rate setting plug at an end of the cylindrical body. A flow bypass communicating with the input port and the output port is provided on an outer peripheral portion of the cylindrical body. When a quantity of a fluid flowing through the flow control valve is reduced, the fluid flowing through the flow bypass compensates the reduction thereof. Accordingly, it is possible to maintain a constant flow rate.

Abstract: In a flow control valve, a spool is fitted into a cylindrical body including an input port and an output port. A spring is disposed between the spool and a flow rate setting plug at an end of the cylindrical body. A flow by-path communicating with the input port and the output port is provided on an outer peripheral portion of the cylindrical body. When a quantity of a fluid flowing through the flow control valve is reduced, the fluid flowing through the flow by-path compensates the reduction thereof. Accordingly, it is possible to maintain a constant flow rate.