Ricoh Company, Ltd.

Kawasaki Jukogyo Kabushiki Kaisha

Kabushiki Kaisha Kawasaki Precision Machinery

Masahiro Matsuo

Hirohisa Abe

Hiroaki Nakanishi

Kunio Matsudaira

Minoru Fukuda

Tomonari Katoh

Shohichi Nitta

Ritsuko Nomura

Shinya Shimizu

Yuko Funakubo

Noboru Ito

Shoichi Nitta

Hiroaki Fujiwara

Makoto Ito

Ryo Yamamoto

Yasunori Hatanaka

Hirokazu Nasu

Yoichi Sakai

Mitsuo Yoshimoto

A relief valve includes: a housing; a plunger movable to each of a closed position and an open position; a differential pressure chamber; a spring member; a piston; and a damping chamber. The plunger includes a first damping passage penetrating the plunger and bringing an area outside the plunger and a through passage into communication. The piston includes a second damping passage penetrating the piston and bringing an area inside the piston and the damping chamber into communication. A communication space connected to each of the first damping passage and the second damping passage is formed between the plunger and the piston.

Relief valve

Provided is a swing-back preventing apparatus capable of preventing a hydraulic actuator in a stop state from operating by undesired load. The swing-back preventing apparatus includes a housing, a piston, and a pair of biasing members. First and second spaces are formed between the piston and the housing, and the piston includes a pair of communication passages that are communicable with first and second spaces. When the piston is located at a first offset position, the first space is blocked from a first port. When the piston separates from the first offset position, the first space is connected to the first port. When the piston is located at a second offset position, the second space is blocked from a second port. When the piston separates from the second offset position, the second space is connected to the second port. When the piston is located at a position on the first offset position side of a neutral position, a first communication passage is connected to the first space. When the piston is located in a range from the neutral position to the second offset position, the first communication passage is blocked from the first space. When the piston is located at a position on the second offset position side of the neutral position, a second communication passage is connected to the second space. When the piston is located in a range from the neutral position to the first offset position, the second communication passage is blocked from the second space.

Swing-back preventing apparatus

In a hydraulic driving system, a plurality of loading-line driving devices adjust a flow rate of an operating liquid flowing from a loading-line pump to a loading-line actuator, and a steering-line driving device adjusts a flow rate of the operating liquid flowing from the steering-line pump to the steering actuator. When one of a plurality of loading-line actuators is driving, a switching valve device connects a loading-side passage and a steering-side passage. When any of the plurality of loading-line actuators is not driving, the switching valve device disconnects the loading-side passage and the steering-side passage.

Hydraulic driving system

A pressure compensation unit includes: a control valve controlling hydraulic fluid supply and discharge to and from an actuator, the control valve including a pump port, a pair of relay and supply/discharge ports, and a tank port; a pressure compensation valve connected to the relay ports by an upstream and downstream-side relay lines, the pressure compensation valve moving in accordance with a pressure difference between upstream-side relay line and signal pressure; a load pressure detection line branching from the downstream-side relay line; a relief line connected to the downstream-side relay line and having a relief valve; and a switching valve leading: a maximum load pressure to the pressure compensation valve as the signal pressure when the hydraulic fluid does not flow through the relief line; and a pump pressure to the pressure compensation valve as the signal pressure when the hydraulic fluid flows through the relief line.

Pressure compensation unit

A relief valve configured such that a plunger configured to be pushed forward by an elastic member to block communication between an inflow opening and an outflow opening moves rearward by an increase in pressure of the inflow opening against an elastic force of the elastic member to cause the inflow opening and the outflow opening to communicate with each other; and a piston configured to push a rear end of the elastic member forward moves forward by the increase in the pressure of the inflow opening to compress the elastic member, the elastic member includes a first elastic member and a second elastic member arranged in series, and the second elastic member has a smaller elastic constant than the first elastic member.

Provided is a configuration in which: a spool driven by an electromagnetic proportional solenoid is urged by a spool-returning spring configured to exert urging force in an opposite direction to a driving direction of the electromagnetic proportional solenoid; a mechanical stopper is disposed at the stroke end of the spool; current dither causes a control current to micro-vibrate, the control current driving the electromagnetic proportional solenoid; and the mechanical stopper includes a stopper-urging spring configured to allow the spool to vibrate owing to the current dither even when the spool is in contact with the mechanical stopper. A proportional solenoid control valve with this configuration is capable of reducing hysteresis at the stroke end of the spool by means of the current dither, and controlling the spool in a stable manner over the entire control range including the stroke end of the spool.

Proportional solenoid control valve

A solenoid includes: a movable core configured to move in a first space of a main body case in an axial direction to apply a biasing force to a spool; a fixed magnetic pole portion configured to attract the movable core in the axial direction; an adjusting spring configured to apply the biasing force to the movable core; a biasing force adjusting member provided at an opening end portion of a rear case and configured to adjust an axial position thereof to adjust the biasing force; and a degassing plug provided at an opening end portion of the adjusting member and including a degassing passage that allows a second space to communicate with an outside by changing relative positions of the adjusting member and the degassing plug. A sealing portion configured to open or close communication between degassing passages is provided between the adjusting member and the degassing plug.

Oil immersed solenoid

A pressure compensated electromagnetic proportional directional flow control valve of the present invention integrally includes: an electromagnetic proportional directional flow control valve configured to be driven by a solenoid; and a pressure compensated valve configured to carry out pressure compensation of a flow rate controlled by the electromagnetic proportional directional flow control valve. A pressure compensation spool moves so as to balance forces of a spring, a first pressure chamber, and a second pressure chamber. With this, the pressure compensation for maintaining a constant pressure difference between an upstream side and a downstream side of a first variable aperture can be carried out, and a surplus liquid of a liquid flowing from a liquid-pressure supply port to a derivation port can flow out from a branch port to outside.

Pressure compensated electromagnetic proportional directional flow control valve

A holding control valve of the present invention is configured such that: a spool is configured to perform strokes by a piston configured to operate by introduction of pilot pressure and have a larger diameter than the spool; the piston is divided into a pilot piston configured to receive the pilot pressure and a relief operation piston disposed adjacent to the spool to receive pressure of relief oil discharged when a relief valve operates; and the relief oil is introduced to between the pilot piston and the relief operation piston.

Holding control valve

The present invention is related to a composite flash memory device comprises a plural sector flash memory array which is divided to plural sector that is a minimum erasing unit of the flash memory device, a flash memory array storing control commands which control a total system of the composite flash memory device and/or the only composite flash memory device in and sharing I/O line of the plural sector flash memory array, the read operation of the flash memory array is enable when the plural sector flash memory array is gained access.

Memory configuration of a composite memory device

A power supply apparatus includes a DC-to-DC converter performing a voltage conversion converting a voltage of a source power supplied from a direct current power source to a first predetermined voltage lower than the voltage of the source power and a voltage regulator carrying out a voltage regulation for regulating the first predetermined voltage of the source power output from the DC-to-DC converter to at least a second predetermined voltage lower than the first predetermined voltage.

Method and apparatus for power supply capable of effectively reducing a power consumption

A step-up/down DC-DC converter is disclosed that includes: a step-up/down part generating an output voltage by stepping up or down an input voltage; and a control part generating an error signal indicating an error between a voltage value obtained by dividing the output voltage and a predetermined reference voltage, and causing the step-up/down part to perform a step-up or step-down operation based on the comparison between the error signal and first and second triangle wave signals. The control part includes a first circuit generating the first triangle wave signal for step-down control and a second circuit generating the second triangle wave signal for step-up control. The first circuit generates a clock signal synchronized with the first triangle wave signal, and outputs the clock signal to the second circuit. The second circuit generates the second triangle wave signal synchronized with the first triangle wave signal based on the input clock signal.

Step-up/down DC-DC converter

A switching regulator including two switching elements and a control switching part. The two switching elements perform a switching operation according to a control signal to control an output voltage. One of the two switching elements is larger in ON-resistance and smaller in control electrode capacitance than the other. The control switching part performs PFM control over the one of the two switching elements to output a first predetermined voltage in a first operation mode, performs PWM control over the two switching elements to output a second predetermined voltage higher than the first predetermined voltage in a second operation mode, and switches the first operation mode to the second operation mode by performing the PFM control, changing the first predetermined voltage to the second predetermined voltage, and switching the PFM control to the PWM control after a first predetermined time elapses since start of increase in the output voltage.

Growing community of inventors

Akashi, Japan

Masahiro Matsuo