Okuma Corporation

Okuma Machinery Works Ltd.

Yasukazu Hayashi

Shinji Shibata

Noriyuki Fukui

Atsushi Ieki

Katsuyoshi Kitagawa

Taishi Shimada

Keiji Matsui

Yasunori Kawakami

Hiroaki Matsuura

Koji Kitagawa

Hisashi Kamabuchi

A sensor substrate includes a multi-layered substrate and a plurality of coils formed on the substrate, an upper-side coil includes a first sub coil including a plurality of conductor patterns connected in series with each other in the substrate, and a second sub coil including a plurality of conductor patterns connected in series with each other in the substrate, and in any of the even number of layers, the conductor pattern belonging to the first sub coil and the conductor pattern belonging to the second sub coil are aligned alternately in a planar direction, and one end of the first sub coil is connected to one terminal of a short land, while one end of the second sub coil is connected to the other terminal of the short land separated from the one terminal in the planar direction.

Sensor substrate for electromagnetic-induction type position sensor and method of manufacturing sensor substrate

A window function calculator applies a Hann window function to Vd (n) to obtain a numeric value Vw (n). For twenty successive numeric values Vw(n) for every twenty numeric values (N=20), each of the Fourier calculators to executes Fourier calculation. Further, the SRSS calculators to calculate square root of sum of squares of SIM and COS components of respective orders of the results of Fourier calculation as numeric values A2, A3, A4, A5. A subtractor calculates a numeric value Ci=A3&#x2212;A5, while a subtractor calculates a numeric value Si=A4&#x2212;A2. A Frequency calculator calculates a numeric value Fi=(m+1+2*A TAN 2 (Ci, Si)/&#x3c0;)/(NT), which indicates the frequency identified. An amplitude calculator doubles the square root of the sum of squares of the numeric values Ci and Si, and calculates a numeric value Ai that indicates the amplitude of the frequency identified.

Frequency identifying device

An insulation deterioration detection device which is mounted in an inverter device including a plurality of switching elements includes: a frequency component extractor which extracts the same frequency component as a frequency of the three-phase alternating current power from the current detection signal of an electric motor winding wire connected to the switching element; and an insulation deterioration detection controller which performs a first switching operation for turning on the switching element and turning off the other switching elements and stores in a first storage device the frequency component extracted by the frequency component extractor during an execution period of the first switching operation, in which it is determined whether insulation deterioration of the electric motor occurs at least based on a value stored in the first storage device.

Insulation deterioration detection device for electric motor

A multi-turn detector is configured to detect an amount of multiple turns of an input shaft using a plurality of resolvers. Each resolver includes a rotor portion and a stator portion. The rotor portion has a rotor core composed of a magnetic flux modulating component. The rotor portion rotates in accordance with rotation of the input shaft at a reduction gear ratio that is different from that of a rotor portion of another resolver. The stator portion has an excitation winding that excites an ac magnetic flux in a direction of an axis of rotation of the rotor portion and two detection windings that output ac signals that are obtained by performing amplitude modulation in accordance with a rotation angle of the rotor portion. The excitation windings and the detection windings of the plurality of resolvers are formed by conductor traces in a common multi-layer printed circuit board.

Multi-turn detector

There is provided a speed monitoring device which can use a low resolution position sensor and provide a high speed response without false detection. The speed monitoring device stores, in a memory unit, a permitted margin PM, a comparison distance VC which is a maximum movement distance permitted for a moving element within one cycle period, and positional data P(t&#x2212;nT) (n is a natural number equal to or less than M) of the moving element obtained from the present time t to M cycles ago. During speed determination, whether |P(t)&#x2212;P(t&#x2212;nT)|&#x3e;VC*n+PM holds true is determined for every integer n from 1 to M. When the inequality holds true, it is determined that the speed exceeds the speed limit.

Speed monitoring device

To provide a linear encoder including a scale unit and a slider that slides along the scale unit, wherein the slider includes a slider enclosure including a slider holding unit, a detection head holding unit mounted inside a scale enclosure of the scale unit, and a pillar extending between the outside and inside of the scale enclosure to connect these two holding units, and a part of the pillar closer to the detection head holding unit and a part of the detection head holding unit closer to the pillar are bored by a thickness larger than a thickness of the pillar.

Linear encoder

An optical encoder, comprising a plurality of light receiving elements 1-12, receiving light that has passed through or been reflected by a scale having a lattice of pitch P, and outputting four-phase signals that have been respectively offset in phase by an integer number of times 90&#xb0; (1/4P). 12 light receiving elements being are in the lateral direction (scale longitudinal direction) with gaps between them of P/60 or 2P/60, four arbitrary light receiving elements arranged next to each other in a row all output signals of different phases, and light receiving elements respectively outputting signals of same phase have three lateral widths of 7OP/60, 13P/60 or 20P/60.

Optical encoder

A position detector includes detection coils for outputting two sinusoidal signals that have phases shifted from each other by 90 degrees; subtractors for eliminating offset components included in output signals DCA and DSC output from the detection coils; an interpolation calculator for converting the two signals DCA and DSC in which the offset components have been eliminated into position information IP; a radius calculator for calculating a root-sum-square of the two signals DC and DS output from the detection coils; correlation calculators for respectively multiplying a fluctuation component RDA of an output from the radius calculator by the signals DCA and DSC in which the offset components have been eliminated; low-pass filters (LPFs) for extracting DC components of output values output from the correlation calculators; and an outputter for outputting offset components including offset displacement fractions based on output values COMDC and SOMDC output from the LPFs.

Position detector

A multi-turn angle sensor includes rotors, each of which rotates in a different manner with respect to an input shaft, and a common stator portion. The rotors and pole teeth disposed around the rotors form each of resolvers. At least two of the resolvers are arranged on a single plane vertical to the rotation central axis of each of the rotors. The common stator portionsurrounding each of the rotors is formed by laminating electromagnetic steel sheets, each of which has an identical shape including a plurality of sets of pole teeth corresponding to each of the rotors. A single length of unspliced electrical wire is wound around each of the pole tooth sets. This facilitates automation of assembly.

Multi-turn angle sensor

Two position sensors provide, as outputs, two signals that vary sinusoidally at a pitch of wavelength &#x3bb; with respect to a displacement of a target and have phases shifted from each other by 90&#xb0;. A memory unit has stored therein offset values for the two signals, and two subtractors eliminate the offset values from the two signals, respectively. The two signals after offset elimination are converted into position data in an interpolation calculator. A radius calculator calculates a radius value of the two signals after offset elimination. An FFT calculates offset values based on the position data and the radius values, and the calculated offset values are used to update the values stored in the memory unit. An amplitude ratio correction value and a phase difference correction value for the two signals are updated similarly. By performing elimination of the components that degrade interpolation accuracy at every rotational position, interpolation accuracy is improved.

In order to cope with many rotor diameters using a single type of stator portion, two stator portions, each having a built-in signal processing circuit for detecting absolute positions independently, are disposed in opposition at positions which differ from each other with respect to a rotational center of a rotor portion. When one of the stator portions receives a request command RX from an external device, it transmits a detected serial communication signal. The other stator portion receives the transmitted serial communication signal, determines a position detection abnormality, and notifies the abnormality to the external device when a difference between the received absolute position and the absolute position detected by the other stator portion exceeds a deviation previously set for 180 degrees.

Abnormality detection apparatus for rotary type absolute encoder

A printed circuit board on which are laid out detection windings and an excitation magnetic flux detection winding formed of conductor patterns is disposed so as to be spaced a predetermined gap quantity from a binary cyclic random number sequence code plate which is rotatably disposed. A U-shaped exciting core on which an excitation winding is wound is disposed on the back surface side of the printed circuit board. The detection windings detect and output, as voltage values, reluctance changes as which excitation magnetic fluxes generated from the excitation winding fluctuate between this excitation winding and the concave/convex portion of the binary cyclic random number sequence code plate. Reduction of precision due to interferences between the excitation magnetic fluxes for detecting an absolute code and other excitation magnetic flux is thereby prevented.

Absolute encoder

A scale section is made of a magnetic material. A repeated pattern is recorded at a uniform pitch on the surface of the scale section. A sensor section is provided independently from the scale section. The sensor section is provided with a magnetic position sensor that reads the pattern, on a surface close to the surface of the scale section. Further, the sensor section is provided with a magnetic tilt sensor that detects a tilt between the surface of the scale section and the surface of the sensor section on which the position sensor is located. The magnetic position detector in which the scale section and the sensor section are separated from each other can be efficiently fixed to a detection target using the tilt sensor.

Position detector with tilt sensor

An absolute position detector for accurately reading a code recorded on an absolute track is provided. Output signals from sensors that read a code recorded on an absolute track are input into a binarization processor. A compensator provided within the binarization processor functions to correct and determine the value of a read target bit based on an output signal from a read sensor which is the sensor located closest to the center of the one-bit width of the read target bit, and an output signal from a compensation sensor, which is a sensor separated from the read sensor by a distance within the range from &#x3bb;/2 to 3&#xb7;&#x3bb;/2.

Absolute position detector

A counter within a rotary encoder outputs 8-bit count data CT for counting up at a period equal to or faster than the transmission period of positional data. When the rotary encoder receives a communication frame for positional data request command STX at a receiving circuit from a servo control apparatus, a sensor control computer feeds a positional detected information including a destination address data DA indicating the servo control apparatus, a source address data SA, 40-bit positional detected data PS, 8-bit status data STS, and count data CT to a transmitting circuit. The transmitting circuit adds a 16-bit cyclic code CRC allowing the detection of an error in the input data to the end of the input positional detected information, converts it to serial data as serial signal SRX, and transmits it to the servo control apparatus.

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Aichi, Japan

Yasukazu Hayashi