Hitachi, Ltd.

Hitachi Construction Machinery Co., Ltd.

Hitachi Construction Machinery

Ken Ichiryu

Ichiro Nakamura

Haruo Watanabe

Morio Tamura

Masayuki Shigeta

Kazuyoshi Hatano

Yasuharu Gotoh

Kiyoshi Tanaka

Yoshimichi Akasaka

Eiji Kometani

Masami Ochiai

Masaki Miura

Takashi Kanai

Tadahiko Nogami

Yoshito Tanaka

Nobuyuki Tobita

Mitsuaki Takenoshita

Nobuyoshi Hidao

Toyotsugu Masuda

Haruo Kinoshita

Hisanobu Kanamaru

Toshiyuki Kajiwara

Takashi Yamaguchi

Tsuyoshi Ogasawara

Nobuhiko Ichiki

Hisayoshi Hashimoto

Kouji Harada

Fujio Sato

Tadashi Shibata

Hideyo Kato

Shigemichi Matsuka

Naohiko Iwata

Hiroshi Yumino

Masatoshi Kuwayama

Katsumasa Matsuura

Masami Nemoto

Yasuo Kido

Yuusaku Nozawa

Fujio Satou

Yukio Murakami

A guide roller assembly for use in a guide roller mechanism of a crawler type vehicle, including a support shaft fixedly provided on a truck frame and a guide roller rotatably mounted on the support shaft through bearings. The guide roller has an integral unitary body structure of a stepped cylindrical shape having a radially bulged portion formed integrally by plastic deformation in an axially intermediate portion between cylindrical end portions of a smaller diameter, and having a uniform wall thickness over the entire length of the guide roller. The guide roller is improved in strength and can realize a substantial cut in production cost.

Guide roller assembly for crawler type vehicles and method for forming

A seal structure in which a hole (5) is defined by a metal base member (4) as a partition member for partitioning the regions on the opposite sides thereof to a gas tight or liquid tight state and a member passes through the hole (5) and extends therefrom. The member passing through the hole (5) may be an electric conductor (2), a pipe member for flowing gas or liquid, a heat pipe for flowing a heat medium, an optical fiber for transferring an optical signal, or the like, and the structure is arranged such that the member passing through the hole is disposed through a synthetic resin seal member (3) and the hole (5) is sealed based on the confinement effected by the plastic deforming action of the base member (4) and the deforming action of the seal member (3) effected by making use of the elastic plasticity thereof, whereby the structure exhibits an excellent pressure resistive performance and can effectively seal the hole (5).

Seal structure for member-passing-through hole bored in metal partition

A sliding member is sulphonitride by heating at 480.degree.-600.degree. C. in the presence of both 10-500 ppm of a hydrogen sulfide gas and a 20-70 vol % ammonia gas, or by a method which comprises performing a primary heat treatment on the sliding member at 450.degree.-540.degree. C. in the presence of 50-200 ppm of a hydrogen sulfide gas and a 10-70 vol % ammonia gas, then ceasing the supply of the ammonia gas, slowly reducing the temperature to a level of 200.degree.-350.degree. C., and performing a secondary heat treatment at that temperature level. By the either method, the sliding member having a FeS.sub.2 on its topmost surface can be obtained.

Method of gas sulphonitriding

A sliding member having a layer of FeS.sub.2 on its surface is formed by sulphonitriding the member by heatint it at 480.degree. C.-600.degree. C. in the presence of both 10-500 ppm of a hydrogen sulfide gas and 20-70 vol % ammonia gas. An alternate heating method involves performing a primary heat treatment on the sliding member at 450.degree.-540.degree. C. in the presence of 50-200 ppm of a hydrogen sulfite gas and a 10-70 vol % ammonia gas, then ceasing the supply of the ammonia gas, slowly reducing the temperature to between 200.degree.-350.degree. C., and performing a secondary heat treatment at that temperature level.

Sliding member, and method and apparatus for producing the same by gas

Pressure sensor

A solenoid operated valve apparatus in which a solenoid device includes an inner yoke, a plunger guide disposed in the opposed relationship with the inner yoke, a plunger movably accommodated in s space formed between the inner yoke and the plunger guide, a bobbin frame disposed to surround the inner yoke and said plunger guide, a coil wound around the bobbin frame, and an outer yoke disposed to surround the coil. The bobbin frame is made of a polymeric material, and is adhered to the inner yoke and the plunger guide in a unitary structure.

Solenoid operated valve apparatus

A flow control valve apparatus includes a housing including a main fluid passage having an inlet port and an outlet port; a main valve disposed between the inlet port and the outlet port for allowing or shutting off communication between the inlet port and the outlet port; a backpressure chamber formed between an inner wall of the housing and a rear portion of a valve member of the main valve, the backpressure chamber communicating with the inlet port through an orifice; an auxiliary passage for placing the backpressure chamber in communication with the outlet port; and a pivot valve for actuating the main valve by controlling the opening and closing of the auxiliary passage and varying the fluid pressure in the backpressure chamber. A differential pressure generating means is disposed in the main fluid passage for generating differential pressures that correspond to the flow rate in the main fluid passage. The differential generating means includes a displacement member disposed for movement in the direction in which a fluid flows in the main fluid passage and spring means for urging the displacement member in the direction opposite to the direction in which the fluid flows, and the displacement member cooperates with a wall surface of the main fluid passage to define a fluid passage having an opening area which increases in accordance with an increase in the stroke of travel of the displacement member.

Flow control valve apparatus

A thrust hydrostatic bearing device for use in an axial piston machine includes a bearing sleeve fitted into a housing cover for rotatably supporting a drive shaft through a bearing and having a plurality of hydrostatic pads. The hydrostatic pads are disposed at locations which are symmetrical with respect to an axis lying in a cross-section taken perpendicular to the drive shaft, and these pads increase the performance and durability of the thrust hydrostatic bearing device for use in an axial piston machine.

Thrust hydrostatic bearing device for use in axial piston machine

A rotary valve in which a valve disc provided disposed in a casing is rotated by a driving device, including a disc-shaped rotor provided in a portion of the valve disc and with a plurality of fan-shaped windings arranged in the circumferential direction, magnets provided in such a manner that the polarities thereof are alternately varied in the circumferential direction and a yoke disposed with a predetermined gap from the magnets. The said rotor is disposed between the magnets and the yoke and constitutes a magnetic circuit for rotating the valve disc directly by an electromagnetic power generated in the magnetic circuit.

Rotary valve

A direct-acting servo valve wherein a spool is directly driven by a force motor including a coiled first bobbin located in a first magnetic circuit composed of a first yoke and a first magnet mounted on the yoke includes a second magnetic circuit composed of a second yoke and a second magnet located at one end of the spool, and a third magnetic circuit composed of third magnets and a magnetic member located at the other end of the spool. The second magnetic circuit serves as means for detecting the velocity of the spool, and the third magnetic circuit serves as means for detecting the displacement of the spool.

Direct-acting servo valve

Disclosed is a hydraulic elevator in which the load and/or the oil temperature are detected under the running condition of a cage of the hydraulic elevator and a proper value of the deceleration delay time corresponding to this running condition is obtained to thereby control the flow of pressure-oil on the basis of the proper value of the deceleration delay time. Various values of the deceleration delay time are stored in advance in the form of table with respect to various values of load and oil temperature.

Hydraulic elevator

An apparatus for detecting leakage of fluid comprises a bridge circuit composed of a heat generating resistance element connected in one arm and installed at a location where leakage of fluid may possibly occur and other resistor elements inserted in other arms, respectively, an input power supply source connected to the input of the bridge circuit and a differential amplifier connected to the output of the bridge circuit for amplifying an unbalance voltage produced by the bridge circuit, wherein the resistor elements inserted in the other arms of the bridge circuit are so dimensioned that the heat generating resistance element is maintained in a heat generating state.

Fluid leakage detecting apparatus

A servo pump for use in a hydraulic system. The servo pump is constituted by a variable displacement type hydraulic pump adapted to be driven by a high-speed motor and to hydraulically drive an actuator. The motor and the pump are housed in a common casing. The motor shaft and the pump shaft are integrated to form a common rotary shaft which is supported rotatably at both its ends by end bearings and at its intermediate portion by an intermediate bearing.

Servo pump for hydraulic systems

A fluid leakage detecting element comprises a heat generating resistive member and a temperature compensating resistive member disposed on a substrate. Each of the resistive members is prepared in the form of a paste of a metal which has a high temperature coefficient and a high thermal conductivity and whose melting point is higher than the baking temperature of the substrate. These resistive members are printed in thick film form on the substrate which is sufficiently electrical insulating and has a high thermal conductivity.

Fluid leakage detecting element

A servovalve apparatus comprising a servovalve and a force motor operatively connected to a valve element of the servovalve for driving the valve element. The force motor includes an annular magnet, and first and second members cooperating with each other to define therebetween an annular gap concentric with the annular magnet. A cylindrical coil operatively connected to the valve element is disposed in the annular gap in concentric relation therewith and is reciprocated within the annular gap in response to the electric current passing through the coil. First and second cylindrical resilient members thermally connect one and the other axial ends of the cylindrical coil to first and second stoppers, respectively, to transmit the Joule heat generated by the coil to the first and second stoppers.

Servovalve apparatus

Growing community of inventors

Ibaraki, Japan

Ken Ichiryu