Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Hiroshi Satoh

Yoshihiko Utsui

Hideo Ikeda

Chiyo Hamamura

Masahiko Hasegawa

Katsuhiko Honda

Shunichi Wada

Noriyuki Inoue

Kiyoshi Hayashi

Masahiro Tado

Kuraki Kitazaki

Takashi Taniguchi

A magnetostriction type stress detector including a passive member to which an external force is applied, which passive member is formed of a magnetic material; a magnetic shielding member provided around the passive member, which magnetic shielding member is formed with a plurality of slits; and a detection coil provided around the magnetic shielding member for detecting a change in magnetic permeability due to a stress in the passive member to be generated by the external force, through the slits of the magnetic shielding member.

Method of manufacturing magnetostriction stress detectors

Magnetostriction type stress detector

A strain sensing apparatus includes a pair of magnetic layers disposed on a shaft to which an external force is applied to cause strain in it. The magnetic layers have magnetic permeabilities which change in opposite directions in response to the strain in the shaft. A sensing coil is disposed to face the magnetic layers with a spacing disposed between the coil and the magnetic layers. An exciting AC voltage is applied across the sensing coil. A change in self-inductance of the coil caused by the permeability changes of the magnetic layers due to the shaft strain is derived as an electrical signal representative of the magnitude of the shaft strain.

Strain sensing apparatus

In a strain measuring device employing a magnetic permeability detector means to detect an amount of strain in a passive member as changes of magnetic permeability in a magnetostrictive layer, a magnetic shielding layer is formed on the surface of the passive member, and the magnetostrictive layer is formed thereon so as to lessen the adverse effects of the passive member caused by the magnetic characteristics of the passive member in strain measurement, that is, to reduce measurement errors. Alternatively, a magnetostrictive layer is formed on the surface of the passive member, or a magnetic shielding layer is partially formed on the surface of the passive member of a soft magnetic material with high permeability, so as to lessen the influence of the passive member caused by thermal stresses of the passive member in strain measurement, that is, to reduce measurement errors. Further, there is provided a strain measuring device which facilitates formation of the magnetostrictive layer.

Strain measuring device employing magnetostriction and having a magnetic

A strain detector wherein the efficiency of a detecting coil is improved to improve the sensitivity of the strain detector. The strain detector comprises a magnetic layer made of a soft magnetic material having a high permeability and fixedly mounted on an outer periphery of a driven shaft strain of which is to be detected, and a detecting coil disposed around the magnetic layer with a gap left therebetween for detecting a variation of the permeability arising from strain of the magnetic layer caused by an external force applied to the driven shaft. The strain detector further comprises a metal layer made of a non-magnetic material having a high electric conductivity and disposed in the gap between the magnetic layer and the detecting coil. Or else, the detecting coil has a pair of coil portions connected to each other by way of an intermediate portion thereof, and an electric current flows in the same direction through the coil portions.

Strain detector

A strain detector wherein external and internal magnetic fields are magnetically separated from each other to eliminate an influence of such disturbance magnetic field to assure accurate and stabilized detection of strain in a drive shaft. The detector comprises a magnetic layer made of a soft magnetic material having a high permeability and suitable magnetostriction fixedly mounted on an outer periphery of a driven shaft, a pair of bearings or bearing stands made of a soft magnetic material having a high permeability for supporting the driven shaft for rotation thereon, a detecting coil disposed around the magnetic layer for detecting a variation of the permeability of the magnetic layer arising from strain of the magnetic layer caused by an external force applied to the driven shaft, and a shield disposed on an outer periphery of the detecting coil and magnetically connected at the axial opposite end portions thereof to the bearings or bearing stands.

A shock absorber control apparatus which performs a fuzzy inference by use of a predetermined fuzzy rule regarding comfortable ride, steering stability and grounding efficiency corresponding to a detected running condition of a vehicle, thereby setting an optimum damping force. A shock absorber control apparatus which fetches a plurality of specified frequency components from a vertical acceleration signal of a vehicle body so as to perform a fuzzy inference by use of a fuzzy rule corresponding to a quantity of each frequency component, thereby setting an optimum damping force.

Shock absorber control apparatus

In a strain measuring device employing a magnetic permeability detector means to detect an amount of strain in a passive member as changes of magnetic permeability in a magnetostrictive layer, a magnetic shielding layer is formed on the surface of the passive member, and the magnetostrictive layer is formed thereon so as to lessen the adverse effects of the passive member caused by the magnetic characteristics of the passive member in strain measurement, that is, to reduce measurement errors. Alternatively, a magnetostrictive layer is formed on the surface of the passive member, or a magnetic shielding layer is partially forrmed on the surface of the passive member of soft magnetic material with high permeability, so as to lessen the influence of the passive member caused by thermal stresses of the passive member in strain measurement, that is, to reduce measurement errors. Further, there is provided a strain measuring device which facilitates formation of the magnetostrictive layer.

A strain detector which has a driven shaft for receiving a stress; a high magnetostrictive rate magnetic layer made of one of Co--B, Co--P, Co--Ni--B, Ni--Fe--P, and Co--Ni--P formed by electroless plating on the outer periphery of the driven shaft; and a detecting coil disposed through a gap on the periphery of the magnetic layer for detecting a variation in the permeability by a strain responsive to the stress of the magnetic layer, a method for manufacturing the strain detector which has the steps of forming a high magnetostrictive plating layer made of one of Co--B, Co--P, Co--Ni--B, Ni--Fe--P and Co--Ni--P by electroless plating on the periphery of the driven shaft; and selectively removing the plating layer to obtain a magnetic layer made of a plurality of magnetic pieces aligned in parallel at a predetermined angle with respect to the central axis of the driven shaft. Thus, the strain detector has high accuracy, high sensitivity and high reliability, and the method for manufacturing the strain detector can inexpensively manufacture the strain detector in good mass productivity.

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Hyogo, Japan

Hiroshi Satoh