Matsushita Electric Industrial Co., Ltd.

Masayuki Wakamiya

Hiroyuki Hase

Rihito Shoji

Ichiro Yamashita

Shinya Tokuono

Nobuyoshi Takeuchi

Munehiro Tabata

Kiyoshi Kojima

Yukihiko Ise

Hiroshi Ueda

Harufumi Senno

Shizuo Furuyama

Tetsuji Fukada

Kikuo Kainou

Omura Hideaki

Hideaki Omura

Kazuhiro Ohyama

Yukio Horita

A magnetic circuit unit for a loud-speaker is provided, in which an adhesion step can be reduced or omitted, magnetic properties can be improved through enhancement of magnetic efficiency, and a durable anti-corrosive treatment can be performed at low price, so that higher performance and lower cost of the loud-speaker can be attained. A method of manufacturing the same is also provided. A top plate has a conical, columnar, truncated conical, or partially spherical hollow part formed on one side whose inner surface is integrated with an anisotropic Nd--Fe--B system magnet under a forming pressure of 100 to 200 kgf/cm.sup.2 through Joule heating by passing a current under compression. The forming die is cooled to a temperature below 100.degree. C. while maintaining the pressure, and the compact is then taken out from the forming die. This integrated compact is adhered to an outer yoke, and a looped yoke and a loop anisotropic Nd--Fe--B system magnet are also adhered thereon to fabricate a magnetic circuit unit. Subsequently, this magnet circuit unit is dipped in acrylic resin emulsion, and a coating of 7 to 15 .mu.m thick is formed by using a rotary coating device.

Magnetic circuit unit for loud-speaker and method of manufacturing the

A metal halide lamp is employed, as a light source, in an optical device such as, for example, an illuminator or an image display. The optical device includes a discharge tube filled with mercury, at least one rare gas, and at least one metal halide, and a pair of electrodes spaced from each other and enclosed in the discharge tube. The optical device also includes an electric circuit, electrically connected to the pair of electrodes, for starting the discharge tube by applying thereto a higher voltage than a voltage to be applied at a steady state to thereby cause an arc discharge in the discharge tube. When the lamp is turned off, power supply thereto from the electric circuit is temporarily interrupted, and when the lamp cools after a first time interval has elapsed subsequent to the interruption of the power supply, a starting voltage is applied to the lamp via the pair of electrodes for a second time interval to cause redischarge. Thereafter, the power supply to the lamp is interrupted after the second time interval has elapsed, to thereby turn off the lamp.

Optical device with metal halide discharge lamp having enhanced starting

In a metal halide lamp container 1 sealed with mercury and rare gas, GdX.sub.3, LuX.sub.3, and CsX where halogen is iodine, bromine, or their mixture are sealed in a total weight of 1 mg/cc or more, with the weight of CsX defined within a range of 15% or more to 50% or less of the total halides, and the weight ratio of GdX.sub.3 and LuX.sub.3 is set in a range of 0.1.ltoreq.GdX.sub.3 /LuX.sub.3 .ltoreq.10. In addition to GdX.sub.3, LuX.sub.3, and CsX, at least one of thallium halide and dysprosium halide is added. Or DyX.sub.3, LuX.sub.3, NdX.sub.3, and CsX where halogen is iodine, bromine or their mixture are sealed in the specified total weight, with the weight ratio of CsX defined in the above range.

Long life metal halide lamp and an illumination optical apparatus and

A torque sensor of the type utilizing magnetostriction of either a shaft made of a magnetostrictive magnetic alloy, or a magnetostrictive magnetic alloy layer formed on an outer peripheral surface of a shaft is disclosed, in which coils are disposed around the shaft for detecting a magnetic property of the magnetostrictive magnetic alloy, a tubular magnetic yoke made of a magnetic alloy having a soft magnetic property and disposed around the coils for excluding the influence of a disturbance magnetic field and completing a closed magnetic circuit, and a hollow cylindrical container disposed around the magnetic yoke. The torque sensor thus constructed has a high measuring accuracy and an excellent thermal stability.

Torque sensor

A non-contact detecting type torque sensor having an enlarged measurable torque range is disclosed, in which a tubular torque transmission member having a mounting portion formed on its inner peripheral surface is fixedly mounted on a shaft, a tubular joining member fitted over the torque transmission member is welded at its opposite ends, a surface magnetic layer having a magnetostrictive properties is formed on an outer peripheral surface of the joining member, and coils are disposed around the surface magnetic layer. With this construction, the magnetic permeability of the surface magnetic layer varies with a torque transmitted from the shaft. A change in magnetic permeability is detected in terms of a change in self-inductance of the coils. The welded ends of the joining member are disposed outside the mounting portion of the torque transmitting member in a longitudinal direction of the shaft, so that the measurable torque range of the torque sensor can be enlarged.

Non-contact detecting type torque sensor

In a bridge circuit of a pressure sensor, resistances are connected in series to the impedances of a pressure detection coil and of a dummy coil for differential provided for deforming and non-deforming parts, and the values of the resistances are smaller than the impedances of the coils. The inductance and the internal resistance of the coils are measured under zero pressure and under the highest rating pressure. The resistance connected to the pressure detector coil is determined so that the sensor output sensitivity, represented as a difference of the sensor outputs under zero pressure and under the highest rating pressure, at the highest temperature agrees with that at the lowest temperature. The resistance connected to the dummy coil is determined so that the sensor output, represented as a difference of the sensor outputs under zero pressure, at the highest temperature agrees with that at the lowest temperature.

Pressure sensor including bridge circuit for detecting permeability of a

A multifunctional torque sensor comprises a torque transmission shaft, a rectangle-shaped or parallelogram-shaped magnetic material strip bonded on the surface of the torque transmission shaft so that opposite sides of the rectangle or parallelogram face each other with a gap interposed therebetween, a first coil concentrically wound around the magnetic material strip, amagnetic core disposed outside of the magnetic material strip in no contact therewith through a space, and a second coil wound around the magnetic material strip. A change in magnetic characteristic caused by a stress transmitted from the torque transmission shaft to the magnetic material strip is detected by the first coil, thereby detecting a torque. The rotation of the shaft is detected through the detection of the gap by the second coil upon rotation of the shaft. A power can be operationally determined from the detected torque and rotation.

Multifunctional torque sensor

A pressure sensor in which a magnetostriction effect of an amorphous magnetic alloy is utilized. It is an object of the invention to suppress the thermal sensitivity change of the pressure sensor and to improve the lineality and the hysteresis of sensor output. The pressure sensor comprises a cylindrical columnar hollow body with a pressure introducing opening, a deforming part of which body is distorted by a pressure introduced from the pressure introducing opening, the deforming part being a peripheral wall of the body, and a thin film made of an amorphous magnetic alloy having a magnetostriction property which is fitted around and bonded to the deforming part, wherein the film, which is curved to have a cylindrical shape and annealed before it is provided around the cylindrical columnar deforming part, has a curvature different from a curvature of the cylindrical columnar deforming part.

Pressure sensor utilizing magnetostriction effect

A pressure sensor has a recess formed in outer surfaces of a deforming part and a non-deforming part such that a pair of steps are formed at opposite ends of the recess. The deforming part is strained by a pressure whereas the non-deforming part is not strained by the pressure. An amorphous magnetic alloy film is received in and affixed relative to the recess, and extends between the pair of steps. The depth of the recess is larger than the thickness of the film. A pair of permeability detector elements are mounted respectively on the deforming part and the non-deforming part so as to detect a change in permeability of the film.

Pressure sensor utilizing a magnetostriction effect

A vibration/acceleration sensor is provided which includes a basic sensor unit fixed to a casing adapted to be mounted on a body the vibrations of which are to be detected. The sensor unit is surrounded by a resinous material having a low heat transfer coefficient. The sensor unit includes a vibration detecting unit including a piezoelectric bending vibrator, thin plates each formed of, for example, a resinous material having a low heat transfer coefficient, provided respectively on the upper and lower surfaces of the vibration detecting unit, and a signal processing circuit formed on the upper thin plate.

Vibration/acceleration sensor

A pressure sensor having the structure wherein an amorphous magnetic alloy member or members are secured to both of a deforming part which is distorted by a pressure and a non-deforming part which is not distorted by a pressure and elements for detecting the change of a permeability of the amorphous magnetic alloy are respectively disposed at each of the amorphous magnetic alloy members, can measure the magnitude of an applied pressure with high accuracy while suppressing a drift of the output accompanied with the change of a temperature.

Pressure sensor

A torque sensor comprising strips of an amorphous magnetic alloy fixed to the surface of a rotary shaft so as to utilize a inverse magnetostrictive effect of the amorphous magnetic alloy is operated in a state in which a predetermined amount of internal compressive strain is previously produced in the strips, so that the torque sensor can operate without any temperature-dependent change in its sensitivity and without occurrence of a hysteresis of its output.

The long-term measurement stability of a magnetostrictive effect strain or stress sensor that uses an amorphous magnetic alloy excited by a magnetic field is improved by generating a magnetic field from an electric current formed from a superposed alternating current waveform and a recurring rectangular current waveform that has a larger amplitude at its start-up and which converges to a smaller amplitude after a predetermined time period or an electric current formed from a superposed direct current component and an alternating current component having constant amplitude and a frequency that varies in a recurring manner between a high frequency and a lower frequency.

Method of operating an amorphous-magnetic-alloy sensor

A stress-sensitive sensor comprising a means for generating magnetic flux, a thin sheet of an amorphous magnetic alloy which is located in the magnetic flux and which is physically deformed in response to an external force to be measured, and a means for detecting the physical deformation as a variation of the magnetic flux which depends on the external force. The amorphous magnetic alloy consists essentially of Fe.sub.a Cr.sub.b Si.sub.c B.sub.d, in which a is a value of from 69 to 81.5 atomic percent, b is a value of from 2.5 to 6 atomic percent, c is a value of from 10 to 15 atomic percent, and d is a value from 6 to 10 atomic percent provided that a+b+c+d=100. The sensor is particularly suitable for oil pressure or torque detection.

Stress-sensitive sensors utilizing amorphous magnetic alloys

A torque sensor includes a cylindrical body disposed concentrically around a shaft and having its opposite ends secured to the surface of the shaft through elastic bodies, a layer of soft magnetic alloy having a magnetostriction property and secured to the surface of the cylindrical body, and a coil disposed concentrically around the layer with an air gap between it and the layer. The torque sensor is constructed such that a strain produced on the surface of the cylindrical body by a torque is converted into a change of a relative permeability of the soft magnetic alloy due to a reverse magnetostriction effect which is detected as a change of inductance of the coil. When the shaft thermally expands or deflects, the elastic bodies act to permit only a torque to be transmitted to the cylindrical body, so that a uniform output is provided without the influence of a thermal strain and deflection of the shaft.

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Suita, Japan

Masayuki Wakamiya