Hitachi Metals, Ltd.

Osamu Shimoe

Shin Nakajima

Rihito Kagawa

Masahiro Mita

Yasunori Abe

Kiyotaka Yamauchi

Kyohei Aimuta

Yukimasa Shonowaki

Kenichi Kanai

Hiroyuki Aoyama

Hitoshi Harata

Hiromitsu Itabashi

Noriyoshi Hirao

Hiroyuki Mima

Sadaji Tashiro

Kazuhiko Osumi

Yuuzo Maruyama

Each of the oscillation frequency of a first oscillation circuit performing oscillation in a state of including a coil and a capacitor and the oscillation frequency of a second oscillation circuit performing oscillation in a state of including a coil and a capacitor different from the coil and the capacitor of the first oscillation circuit is measured. Then, the difference of the measured oscillation frequencies is calculated and then the calculated difference is converted into a magnetic permeability or a dielectric permittivity. One sensor selectively detects a change in the magnetic permeability or a change in the dielectric permittivity of a subject material.

Magnetic permeability sensor and magnetic permeability detecting method, dielectric permittivity sensor and dielectric permittivity detecting method, and magnetic permeability and dielectric permittivity sensor and magnetic permeability and dielectric permittivity detecting method

An apparatus for detecting a rotation angle using a magnet rotor comprising a magnet having 2N poles, wherein N is a natural number, and a sensor device for detecting the direction of a magnetic flux from the magnet rotor, at least one of two output voltages obtained in radial and rotational directions by the sensor device being multiplied by a correction coefficient, and the rotation angle being calculated from the two corrected output voltages to increase the detection accuracy of the rotation angle.

Rotation-angle-detecting apparatus, rotating machine and rotation-angle-detecting method

A rotation-angle-detecting apparatus comprising a magnet rotor having 4 or more magnetic poles on the surface, and sensor device for detecting magnetic flux from the magnet rotor, and an electronic circuit for outputting a signal representing the rotation angle of the magnet rotor using pluralities of signals obtained from the sensor device, the sensor device having pluralities of spin-valve, giant-magnetoresistive devices for outputting two or more different phase signals from a rotating magnetic field near the rotating magnet, each spin-valve, giant-magnetoresistive device having a pinned layer and a free layer, the magnetization direction of the pinned layer being fixed, and the magnetization direction of the free layer rotating depending on a magnetic field direction, pluralities of the spin-valve, giant-magnetoresistive devices comprising a first spin-valve, giant-magnetoresistive device having a reference magnetic-field-sensing direction, and a second spin-valve, giant-magnetoresistive device having a magnetic-field-sensing direction different from that of the first spin-valve, giant-magnetoresistive device.

Rotation-angle-detecting apparatus, rotating machine, and rotation-angle-detecting method

To provide a thin and small area azimuth meter. A plane coil and at least two groups of thin film magneto resistive elements are arranged. Each of the groups of thin film magneto resistive elements constitutes an MR bridge and detects and outputs two perpendicular components of the earth magnetism, and bearing information is obtained based on the output values.

Azimuth meter

To provide a bearing sensor having a thin plane coil for applying a biasing magnetic field and at least one magneto resistive element pair (a first magneto resistive thin plate and a second magneto resistive thin plate) crossing opposed conductor sides of the coil. The plane coil has at least one pair of opposed conductor sides (a first side and a second side). The first magneto resistive thin plate and the first side cross one another at an angle more than 30 degrees and less than 90 degrees. The second magneto resistive thin plate and the second side cross one another at an angle more than 30 degrees and less than 90 degrees. While biasing magnetic fields in opposite directions are applied to the magneto resistive thin plates, respectively, intermediate potentials of the magneto resistive element pair are measured to determine bearings based on the difference between the intermediate potentials.

Bearing sensor having magneto resistive elements

A surge current-suppressing circuit for an accelerator comprising a magnetic device inserted between a high-voltage DC power supply and an ion source for suppressing surge current generated when electric charge stored in a stray capacitance existing between the high-voltage DC power supply and the load is released at the time of short-circuiting of the load. The magnetic device comprises a magnetic core constituted by interlaminar-insulated thin ribbons of an iron-base amorphous or fine crystalline soft magnetic alloy. The iron-base fine crystalline soft magnetic alloy has the composition represented by the general formula:

Surge current-suppressing circuit and magnetic device therein

A magnetic sensor has first, second, third and fourth magneto-resistance effect elements disposed in a direction of a magnetizing pitch (1) of a magnetic recording medium serving to supply a magnetic signal, with first and second magneto-resistance effect elements disposed spacedly from each other at an interval corresponding to an electrical angle of .theta., the third and fourth magneto-resistance effect elements disposed spacedly from each other at an interval corresponding to an electrical angle of (360.degree.-.theta.), and the intervals between the center line of the first and second magneto-resistance effect elements and between the line of the third and fourth magneto-resistance effect elements being set to n.lambda.. The four magneto-resistance effect elements are connected to one another in series in the order of the first, second, fourth and third magneto-resistance effect elements with both ends of the serially-connected magneto-resistance effect elements being provided with a power source terminal, and an output terminal being provided at a conjunctive point of the second and fourth magneto-resistance effect elements. .theta. is set to a range of 30.degree..ltoreq..theta..ltoreq.90.degree., based on .lambda.=360 to thereby enable an output wave form of the magnetic sensor to have a large or sharp gradient in the vicinity of a comparing level.

Magnetic sensor having spaced magneto-resistance elements

A first high-voltage pulse generating circuit comprises a magnetic pulse compression circuit having a main saturable reactor provided with a reset circuit, the reset circuit being provided with a second saturable reactor for providing pulse voltage or current for setting a magnetic flux density of the main saturable reactor at a gate initiation point to a predetermined constant level. A second high-voltage pulse generating circuit comprises a magnetic pulse compression circuit having a main saturable reactor, a preset circuit for magnetizing the main saturable reactor to a saturation region thereof, and a set circuit for setting a magnetic flux density of the main saturable reactor at a gate initiation point to a predetermined constant level.

High-voltage pulse generating circuit, and discharge-excited laser and

A high-voltage pulse generating circuit comprising a magnetic pulse compression circuit having a saturable reactor, and a variable inductor provided on the input side of the saturable reactor for controlling a pulse width of voltage pulse to be applied to the saturable reactor. This circuit may be used in discharge-excited lasers such as excimer lasers and accelerators such as linear induction accelerators.

A DC-DC converter having a transformer having a primary winding and a secondary winding; means for supplying DC input voltage to the primary winding; at least one switching element connected between the DC input voltage supplying means and the primary winding; rectifying means; at least one saturable reactor having a first winding and a second winding, the first winding being connected between one end of the secondary winding which is positive while the switching element is in a turn-on state and the rectifying means; and reset control circuit means connected to the second winding of the saturable reactor for supplying reset voltage thereto in response to output voltage of the rectifying means. The first and second windings have such polarities that the reset voltage can reset the saturable reactor during a turn-off period of the switching element. This DC-DC converter enjoys less temperature rise in the saturable reactor and a lower level of noise generation.

DC-DC converter with saturable reactor reset circuit

A toner level sensor for detecting the presence or absence or the level of residual amount of the toner of an electronic copier or the like. In order to secure stable operation regardless of changes of external environmental conditions such as temperature and humidity, a pair of transformers are provided with primary coils and secondary coils respectively wound on magnetic cores having a magnetic gap. When a magnetic member is present in the vicinity of a magnetic gap, the phases of the outputs of the secondary coils are opposite to each other, so that the differential output of the secondary coils is phase detected to determine the presence or absence of the residual toner amount or the level of residual amount.

Growing community of inventors

Kumagaya, Japan

Osamu Shimoe