Abstract: A magnetically responsive member is disposed on a rotating member along the circumference of the rotating member in such a manner that the magnetically responsive member rotates together with the rotating member, and the magnetically responsive member is formed in a line-shaped pattern varying cyclically in a rotational axis direction. A stator is disposed around the rotating member in a contactless manner, and the stator includes a primary coil wound around the rotating member, and a secondary coil forming a loop pattern of a plurality of cycles along the circumference of the rotating member. As the primary coil is AC-energized, an induced AC output signal corresponding to relative positions between the line-shaped pattern of the rotating member and the loop pattern of the secondary coil, which depend on a rotational position of the rotating member, is output from the secondary coil.

Abstract: A device has a construction capable of promoting miniaturization, and comprises: a coil; a magnetism-responsive member disposed so as to be displaced relative to the coil according to a position of a detection object; and a self-oscillation circuit that incorporates the coil therein as an oscillation element so that an oscillation frequency varies with an inductance variation of the coil responsive to an displacement of the magnetism-responsive member relative to the coil. An arithmetic section generates a measured value responsive to oscillation frequency based on an oscillation output of the self-oscillation circuit, calculates velocity data by differentiating successive measured values, and calculates displacement data by integrating the velocity data.

Abstract: In a position detection device of a type that omits a secondary coil, various inconveniences arising from the use of a voltage-dividing resistance (fixed resistor) are eliminated. At least two pairs of coils are provided. A magnetism-responsive member are placed so as to effect relative displacement in relation to the coils, the relative position of the member in relation to the coils varies with a position of a detection object, and impedance of each coil is varied with the relative position. The impedance changes of two coils constituting each one of coil pairs present characteristics of mutually opposite phase characteristics. For each coil pair, the two coils constituting the pair are connected in series with each other, and from a connection point thereof, a voltage-divided output voltage according to the impedance of the two coils is taken out as a detection output signal for the pair.

Abstract: A coil section includes a primary coil which is magnetically excitable by an AC signal, and secondary coils which are provided so as to generate an inductive output in response to excitation of the primary coil. A self-oscillation circuit, including an inductance element and a capacitor, has incorporated therein the primary coil as the inductance element for self-oscillation. A target section is provided in such a manner that its relative position to the coil section varies according to a position of a target of detection, and the target section includes a magnetically responsive member disposed so that inductance of the secondary coils is varied according to the relative position. Amplitude levels of the output signals of the secondary coils are extracted, and position data of the position of the target of detection is obtained on the basis of these amplitude levels.

Abstract: A detection coil incorporated in a self-oscillation circuit, which includes the coil and a capacitor and is set to a high frequency band (e.g., around 1 MHz or higher). A target section has a relative position to the coil section that varies in response to displacement of a detection object and includes a magnetism-responsive member constructed to cause inductance of the coil to vary with the relative position. A rectifier circuit extracts an amplitude level of an oscillation output signal of the self-oscillation circuit and outputs the extracted level as detected position data. For example, a plurality of self-oscillation circuits are provided. Alternatively, a single self-oscillation circuit forms a plurality of series circuits by, for each coil pair, connecting in series the two coils of the coil pair, and connecting the series circuits in parallel as an inductor element for self-oscillation.

Abstract: An excitation AC signal biased by a predetermined DC voltage is applied to a coil to allow a DC voltage component in a coil output signal to contain failure information about disconnection, partial disconnection, or the like of the coil. The DC voltage component contained in the coil output signal is detected, and the detected DC voltage is provided as an offset voltage for a failure diagnosis. Further, to check a peak level of the excitation AC voltage, a DC voltage corresponding to the peak level may be contained in the offset voltage. A differential amplifier circuit for obtaining a difference between a coil detection output AC voltage component and a reference AC voltage component outputs an obtained differential signal offset by the offset voltage. Accordingly, the differential signal containing the offset voltage as the failure information is transmitted to a circuit for torque measurement as a torque detection signal via a single output line.

Abstract: Flow rate control valve includes: a target probe formed of a magnetically-responsive substance and mounted to one end of a spool; a sensor housing mounted to the one end of the sleeve and having a cylinder section defining an inner space to permit entry therein of the target probe; and first and second coils provided around the cylinder section and axially spaced from each other by a predetermined distance. The probe is constructed so that magnetic response of the coils gradually varies in one direction in response to a linear position of the target probe. The first coil responds to the target probe, while the second coil does not respond to the target probe. Impedance of the first coil varies with a linear position of the probe (31), and the linear position of the probe is detected through differential synthesis performed between outputs of the first and second coils.

Abstract: An excitation AC signal biased by a predetermined DC voltage is applied to a coil to allow a DC voltage component in a coil output signal to contain failure information about disconnection, partial disconnection, or the like of the coil. The DC voltage component contained in the coil output signal is detected, and the detected DC voltage is provided as an offset voltage for a failure diagnosis. Further, to check a peak level of the excitation AC voltage, a DC voltage corresponding to the peak level may be contained in the offset voltage. A differential amplifier circuit for obtaining a difference between a coil detection output AC voltage component and a reference AC voltage component outputs an obtained differential signal offset by the offset voltage. Accordingly, the differential signal containing the offset voltage as the failure information is transmitted to a circuit for torque measurement as a torque detection signal via a single output line.

Abstract: A plurality of layers of flat coils are stacked and connected in series with each other to form a single coil pole, and the coil pole is energized by an A.C. signal. Magnetism-responsive member, provided to be opposed to the coil pole in a non-contact manner, is displaced relative to the coil pole, so that correspondency, to the coil section, of the magnetism-responsive member varies in response to variation in the relative position and thus impedance variation occurs in the coil pole. Position detection signal is provided on the basis of an output signal, responsive to the impedance variation, taken out from the coil pole.

Abstract: A first sensor detects a rotational position of a first shaft in a noncontact fashion and generates a first output signal by phase-shifting a reference A.C. signal in accordance with the detected rotational position of the first shaft. A second sensor detects a rotational position of a second shaft in a noncontact fashion and generates a second output signal by phase-shifting the reference A.C. signal in accordance with the detected rotational position of the second shaft. First and second timing signals corresponding to phase shift amounts of the first and second output signals are output via respective output lines. Relative rotational position detection data, representing a rotational difference or amount of torsion between the two shafts, appears in a time difference between the first and second timing signals. A PWM signal, having a pulse width corresponding to a time difference between the first and second timing signals, may be output.

Abstract: A plurality of layers of flat coils are stacked and connected in series with each other to form a single coil pole, and the coil pole is energized by an A.C. signal. Magnetism-responsive member, provided to be opposed to the coil pole in a non-contact manner, is displaced relative to the coil pole, so that correspondency, to the coil section, of the magnetism-responsive member varies in response to variation in the relative position and thus impedance variation occurs in the coil pole. Position detection signal is provided on the basis of an output signal, responsive to the impedance variation, taken out from the coil pole.

Abstract: A first sensor detects a rotational position of a first shaft in a noncontact fashion and generates a first output signal by phase-shifting a reference A.C. signal in accordance with the detected rotational position of the first shaft. A second sensor detects a rotational position of a second shaft in a noncontact fashion and generates a second output signal by phase-shifting the reference A.C. signal in accordance with the detected rotational position of the second shaft. First and second timing signals corresponding to phase shift amounts of the first and second output signals are output via respective output lines. Relative rotational position detection data, representing a rotational difference or amount of torsion between the two shafts, appears in a time difference between the first and second timing signals. A PWM signal, having a pulse width corresponding to a time difference between the first and second timing signals, may be output.

Abstract: First and second shafts (1, 2) are interconnected via a torsion bar (3) for torsional (or rotational) movement relative to each other, and first and second magnetic body sections (10, 20) are provided to rotate in interlocked relation to the rotation of the first and second shafts, respectively. The first and second magnetic body sections form at least two ring-shaped variable magnetic coupling sections opposed to each other via a gap, magnetic coupling in each of the boundary sections varies in response to variation of a relative rotational position between the first and second shafts, and variation of the magnetic coupling differs in phase between the boundary sections. Coil section (30) includes magnetic-coupling detecting coils (L1-L4) provided in corresponding relation to the boundary sections.

Abstract: First and second shafts (1, 2) are interconnected via a torsion bar (3) for torsional (or rotational) movement relative to each other, and first and second magnetic body sections (10, 20) are provided to rotate in interlocked relation to the rotation of the first and second shafts, respectively. The first and second magnetic body sections form at least two ring-shaped variable magnetic coupling sections opposed to each other via a gap, magnetic coupling in each of the boundary sections varies in response to variation of a relative rotational position between the first and second shafts, and variation of the magnetic coupling differs in phase between the boundary sections. Coil section (30) includes magnetic-coupling detecting coils (L1-L4) provided in corresponding relation to the boundary sections.

Abstract: An outer cylindrical section is rotatable with a first shaft. Magnetic shielding portions are formed of a magnetic shielding or antimagnetic substance and arranged on a surface of a nonmagnetic and nonconductive cylindrical base. The magnetic shielding portions are spaced apart from each other by a predetermined interval in a circumferential direction of the cylindrical base so that non-magnetically-shielding portions are formed between the magnetic shielding portions. A plurality of coils are provided on a periphery of the outer cylindrical section and excitable by a predetermined A.C. signal. An inner cylindrical section is inserted in the outer cylindrical section and rotatable with a second shaft. The inner cylindrical section includes magnetic portions each provided to present a different characteristic with respect to an arrangement of the plurality of coils.

Abstract: An outer cylindrical section is rotatable with a first shaft. Magnetic shielding portions are formed of a magnetic shielding or antimagnetic substance and arranged on a surface of a nonmagnetic and nonconductive cylindrical base. The magnetic shielding portions are spaced apart from each other by a predetermined interval in a circumferential direction of the cylindrical base so that non-magnetically-shielding portions are formed between the magnetic shielding portions. A plurality of coils are provided on a periphery of the outer cylindrical section and excitable by a predetermined A.C. signal. An inner cylindrical section is inserted in the outer cylindrical section and rotatable with a second shaft. The inner cylindrical section includes magnetic portions each provided to present a different characteristic with respect to an arrangement of the plurality of coils.

Abstract: The present invention provides a bending machine that enables an angle measuring instrument to be compactly built into a mold for accurate processing. The present invention also provides an operation method besed on learning control which achieves accurate bending with this bending machine taking spring back into consideration. A bending machine carries out bending using lineraly extending an upper die 4 and a lower die 2, the upper die 4 having a built-in angle measuring instrument 9. The angle measuring instrument 9 is composed of a corner contacting member 12 with links and an inductive linear position detector 13 for measuring displacement of the corner contacting member 12. In operation for learning, the position of and a load on the upper die 4 and a bend angle are measured during a bending process and a bend angle after spring back is subsequently measured.

Abstract: Within a body, a sensor member, which has one end supported in a cantilever fashion adjacent a predetermined end of the body and has the other end extending into a space of the body, includes a coil section having a plurality of coil segments that are excitable in a same phase by a predetermined A.C. signal and sequentially arranged along a direction of linear movement of a movable member. The movable member has an inner space to permit entry of the sensor member into the movable member. Inner peripheral wall of the movable member defining the inner space includes a magnetism-responsive substance containing a magnetic or electrically-conductive material.