Kawasaki Jukogyo Kabushiki Kaisha

Mitsubishi Denki Kabushiki Kaisha

Toyoaki Sagawa

Kazuto Fujiyama

Yoshio Togashi

Tokihiko Umeda

Toshiyuki Yoshida

Koji Sakashita

Kimihiko Murase

Makoto Sonoda

The present invention intends to improve a hydraulic control unit and prevent the occurrence of hunting as well as to reduce the size of the hydraulic control unit. The hydraulic control unit is used in a several-directional-control-valves-assembled-type hydraulic control system 1 having a load sensing function. The hydraulic control unit has a PLS port. The PLS port is supplied with a maximum load pressure in the hydraulic control system. The compensator of the hydraulic control unit includes a metering orifice imparted with a function equivalent to a check valve. The compensator is imparted with the function of a shuttle valve (directional control valve), and by allowing the shuttle valve to operate independently of the compensator the pressure PLS is adjusted constantly.

Hydraulic controller

Joystick control actuator

In order to obtain great damper effects with a comparatively simple structure and fully control a hunting phenomenon, a pilot valve comprises push rods attached to a valve body, spools attached to spools holes of the valve body, spring bearing members provided in spring chambers of the valve body, first spring members provided between the valve body and the spring bearing members, second spring members provided between the spring bearing members and the spools, and an operation level for pressing the push rods. A fluid chamber is provided on an outside of one of ends of each of the spool holes. The fluid chamber communicates with a drain passage through a throttle passage having a throttle portion.

Pilot valve

A bridge apparatus which judges whether a destination address of a frame relayed to a trunk line LAN is registered in other bridge apparatus or not using a control apparatus provided therein, relays the frame with a proper destination address in accordance with the result of the judgment, and allows the relaying to be carried out securely even if an address of a destination terminal has not been registered in the bridge apparatus.

Bridge apparatus

A relief valve to be disposed in a hydraulic circuit, for example an absolute circuit, such as in an industrial construction machine, comprises a casing of substantially cylindrical structure having one end and another end, the casing including a casing body, a pressure regulating plug and a lid member. The relief valve further comprises a valve seat fitted into one end of the casing and provided with an inflow hole through which a pressurized fluid is flown, a plunger disposed in the casing and having one flanged end slidably engaged with an inner surface of the one end of the casing, the plunger having a central through hole, a stepped piston member disposed in the casing to be slidable therein and having an outwardly stepped one end and a spring member disposed between another end of the stepped piston member and the flanged one end of the plunger. A fluid chamber is defined between another end of the casing and the one end of the stepped piston member. A damping chamber is defined between the stepped portion of the stepped piston member and the stepped portion formed to the casing. The fluid chamber and the damping chamber is communicated with each other through a communication passage. The through hole of the plunger having a throttle portion having a predetermined length and the other end of the stepped piston member having an outer diameter substantially equal to an inner diameter of the inflow hole of the valve seat.

Relief valve

The present invention relates to relief valves, and is drawn to a relief valve that alleviates the rise in the relief pressure, by the compression of a main spring via a moving spring receiving member, due to the introduction of hydraulic pressure at the supply side into a fluid chamber at the rear of a movable spring member. Moreover, an adjustment spring to urge the moving body and to assist the main spring is provided within a fluid chamber, and the urging force of this adjustment spring can be adjusted by the operation of a changing member provided externally of the valve. Thus, the set pressure of the relief valve can be easily and readily changed, and also a fine adjustment of the set pressure can be effected.

A swash-plate type piston pump motor has a housing assembly comprising: an end plate for rotatably supporting a cylinder rotor against thrust loads in its axial direction and also rotatably supporting the upper end of an output shaft; a cylinder side peripheral wall encompassing the cylinder rotor; an inner peripheral wall which is joined contiguously to the cylinder side peripheral wall and extends downward toward the lower end of the output shaft. The inner peripheral wall encloses and supports a swash plate in an inclined state. A downwardly extending outer peripheral wall is also joined contiguously to the cylinder side peripheral wall and is flared outward toward the lower end of the output shaft, an annular space being formed between the inner and outer peripheral walls. The maximum flare angle of the outer peripheral wall relative to the axial direction of the output shaft is 30 degrees. The outer peripheral wall has at its open flare extremity a motor mounting flange. The rigidity of the outer peripheral wall is thereby increased, and generation of vibrations and noise therefrom is effectively prevented. The outer peripheral wall also functions as a shield to contain and suppress noise generated at the outer surface of the inner peripheral wall.

Growing community of inventors

Kobe, Japan

Toyoaki Sagawa