Other

Amiteq Co., Ltd.

Atsutoshi Goto

Eaton Corporation

Kazuya Sakamoto

Hiroshi Sakamoto

Yasuhiro Yuasa

Nobuyuki Akatsu

Shuichi Tanaka

Akio Yamamoto

Daisuke Goto

Wataru Ichikawa

Shunitsu Ito

Eiichi Hirai

Shigeru Muraoka

Shoji Tozawa

Masakuni Tanaka

Shuiti Tanaka

Hiroshi Sakamato

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.

Position detection device

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.

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. The circuit for torque measurement provides the torque detection data based on the transmitted differential signal and at the same time extracts the offset voltage to use it for the failure diagnosis.

Torque sensor

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.

Position sensor having stacked flat coils

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.

Relative rotational position detection apparatus

First and second shafts () are interconnected via a torsion bar () for torsional (or rotational) movement relative to each other, and first and second magnetic body sections () 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 () includes magnetic-coupling detecting coils (L-L) provided in corresponding relation to the boundary sections. Each of the first and second magnetic body sections is of a cylindrical shape and has a plurality of magnetic teeth formed at unequal pitches along the circumferential direction thereof, and the magnetic teeth differ in axial length among tooth groups corresponding to the boundary sections.

Relative rotational position detection apparatus having magnetic coupling boundary sections that form varying magnetic couplings

Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(&#x3c9;t&#xb1;d+&#x3b8;), sin((&#x3c9;t&#xb1;d&#x2212;&#x3b8;)) are electrically synthesized which have electric phase angles (&#x3b8;) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. '&#xb1;d' here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (&#xb1;d) appear in the same direction, while the phase differences (&#x3b8;) corresponding to the position are shifted in opposite, positive and negative, directions. Thus, by measuring the respective phase shift amounts (&#xb1;d+&#x3b8;, &#xb1;d&#x2212;&#x3b8;) and performing appropriate operation, it is allowed to cancel out or extract the error (&#xb1;d) so that an accurate phase difference (&#x3b8;) can be detected. Position detection data indicative of the detected phase difference (&#x3b8;) is converted into a pulse-width-modulated signal and transmitted in the pulse-width-modulated form.

Phase difference detection device and method for a position detector

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. Degree of overlap between the non-magnetically-shielding portions of the outer cylindrical section and the magnetic portions of the inner cylindrical section varies in response to a variation in the relative rotational position between the first shaft and the second shaft, and each of the coils presents impedance corresponding to the degree of overlap.

Relative-rotational-position detection apparatus

In a control unit for use with a power steering apparatus, there are provided and integrated into a single body, a main operating fluid feed device for supplying the hydraulic cylinder with an amount of oil corresponding to the amount of rotation of the steering wheel H, an auxiliary operating fluid feed device for supplying a correcting oil for adjusting drive of said hydraulic cylinder according to control signal, and a steering wheel angle sensor disposed around the rotating shaft of the steering wheel connected to said main operating fluid feed device, to detect steering wheel angle corresponding to the rotating position of said steering wheel.

Control unit for power steering apparatus and steering-wheel-angle correcting system

Single coil to be excited by a predetermined A.C. signal is provided, with no secondary coil being provided. Magnetism-responsive member is movable relative to the coil so that a self-inductance of the coil progressively increases or decreases in response to displacement of an object to be detected within a predetermined range and a voltage of the coil corresponding to the self-inductance is produced. Predetermined reference voltage is generated and subjected to analog operations with the coil output voltage, to thereby generate first and second A.C. outputs having, as amplitude coefficients, first and second cyclic amplitude functions correlated to the position to be detected. The position is detected on the basis of the phase component of the amplitude coefficient functions. Combination of two coils and one reference voltage may be employed.

Self-induction-type position detector device for detecting object position

An outer cylinder having patterns of open windows of first to fourth channels is formed of a magnetic-shielding or antimagnetic substance. An inner cylinder is inserted in the outer cylinder, is formed of a magnetic substance and has patterns of nonmagnetic windows of the first to fourth channels. First to fourth coils excitable by A.C. are provided for the first to fourth channels. For each of the channels, the pattern of the open window in the outer cylinder and the pattern of the nonmagnetic window in the inner cylinder are arranged to overlap with each other. Arrangement of the windows in the channels is set such that: degree of overlap between the pattern of the open window and the pattern of the nonmagnetic window in each of the channels varies in accordance with a variation in a relative rotational position to be detected; a variation in the degree of overlap in the second channel presents a differential characteristic relative to a variation in the degree of overlap in the first channel; a variation in the degree of overlap in the fourth channel presents a differential characteristic relative to a variation in the degree of overlap in the third channel; and variations in the third and fourth channels present a predetermined difference from variations in the first and second channels.

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 and a lower die , the upper die having a built-in angle measuring instrument . The angle measuring instrument is composed of a corner contacting member with links and an inductive linear position detector for measuring displacement of the corner contacting member . In operation for learning, the position of and a load on the upper die and a bend angle are measured during a bending process and a bend angle after spring back is subsequently measured. Based on the interrelationship between the measured values, a next correction value is obtained for an adjustable position of the bending machine which controls the bend angle.

Bending machine and its operation method

The present invention is directed to a position detection method and apparatus whereby a first A.C. output signal having an electric phase angle shifted in a positive direction in accordance with a position-to-be-detected is produced along with a second A.C. output signal having an electric phase angle shifted in a negative direction. First and second detection data are then generated by detecting respective phase differences of the first and second A.C. output signals from a predetermined reference phase. The first and second predicted values are provided on the bases of at least two successive samples of the first and second detection data, respectively. The first and second predicted values are then modified to provide a standard predicted value for correcting any nonlinear error resulting from the Doppler effect. Using this standard predicted value, predictive interpolation is performed on the first and second detection data sequentially with the passage of time to provide first and second interpolated data.

Position detection data generating method and apparatus based on phase shift principle

Single coil to be excited by a predetermined A.C. signal is provided, with no secondary coil being provided. Magnetism-responsive member is movable relative to the coil so that a self-inductance of the coil progressively increases or decreases in response to displacement of an object to be detected within a predetermined range and a voltage of the coil corresponding to the self-inductance is produced. Predetermined reference voltage is generated and subjected to analog operations with the coil output voltage, to thereby generate first and second A.C. outputs having, as amplitude coefficients, first and second cyclic amplitude functions correlated to the position to be detected. The position is detected on the basis of the phase component of the amplitude coefficient functions. Combination of two coils and one reference voltage may be employed. Further, a plurality of coil segments excitable by a same-phase signal are placed in series along the direction of displacement of the object so that a progressive increase or decrease occurs sequentially in the self-inductance of the coil segments as the magnetism-responsive member moves relative to the coil segments, and the voltage corresponding to the self-inductance is taken out from each of the coil segments. Performing analog arithmetic operations on combinations of the coil voltages produces first and second A.C. outputs having, as amplitude coefficients, first and second cyclic amplitude functions correlated to the position to be detected.

Two A.C. output signals amplitude-modulated in accordance with two function values (sine and cosine) differing from each other in correspondence to a position-to-be-detected are received from a position sensor such as a resolver. By performing an addition or subtraction between a signal derived by shifting the electric phase of one of the received A.C. output signals by a predetermined angle, and the other received signal, two electric A.C. signals (sin(&ohgr;t&plusmn;d&plus;&thgr;), sin(&ohgr;t&plusmn;d&minus;&thgr;)) are electrically synthesized which have electric phase angles (&thgr;) corresponding to the position-to-be-detected and are phase-shifted in opposite directions. &ldquo;&plusmn;d&rdquo; here represents phase variation error caused by factors, other than the position-to-be-detected, such as temperature change. In the synthesized two signals, the phase variation errors (&plusmn;d) appear in the same direction, while the phase differences (&thgr;) corresponding to the position are shifted in opposite, positive and negative, directions. Thus, by measuring the respective phase shift amounts (&plusmn;d&plus;&thgr;, &plusmn;d&minus;&thgr;) and performing appropriate operation, it is allowed to cancel out or extract the error (&plusmn;d) so that an accurate phase difference (&thgr;) can be detected. Position detection data indicative of the detected phase difference (&thgr;) is converted into a pulse-width-modulated signal and transmitted in the pulse-width-modulated form.

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Fuchu, Japan

Atsutoshi Goto