Patents Assigned to Okuma Corporation
  • Patent number: 11125608
    Abstract: 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?A5, while a subtractor calculates a numeric value Si=A4?A2. A Frequency calculator calculates a numeric value Fi=(m+1+2*A TAN 2 (Ci, Si)/?)/(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.
    Type: Grant
    Filed: June 17, 2020
    Date of Patent: September 21, 2021
    Assignee: OKUMA CORPORATION
    Inventor: Yasukazu Hayashi
  • Patent number: 11079734
    Abstract: Respective amounts of movement of feed axes corresponding to first and second position controllers are determined, and if a value obtained by dividing a smaller amount of movement by a larger amount of movement, in the two amounts of movement, falls within a prescribed reference range, a position controller for the feed axis with the smaller amount of movement selects a detected motor position as a position feedback value and a position controller for the other feed axis selects a detected object position as a position feedback value.
    Type: Grant
    Filed: March 14, 2019
    Date of Patent: August 3, 2021
    Assignee: OKUMA CORPORATION
    Inventor: Noriyuki Fukui
  • Patent number: 11073561
    Abstract: 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.
    Type: Grant
    Filed: March 11, 2019
    Date of Patent: July 27, 2021
    Assignee: OKUMA CORPORATION
    Inventor: Yasukazu Hayashi
  • Patent number: 11048235
    Abstract: In a controller of a machine tool having a converter that converts an AC power supply to DC and a plurality of inverters that drive a feed axis and a spindle, a power outage preparation mode is judged when an AC power supply voltage becomes lower than a predetermined value, and power outage is judged when the power outage preparation mode continues for a time period exceeding a predetermined time period or when a DC voltage which is output from the converter becomes lower than VAL1. During the power outage preparation mode, a threshold VAL2 of a low voltage alarm provided at each inverter is changed to a value lower than VAL1. In addition, when the power outage is judged, a stopping operation or a retracting operation of the feed axis is executed.
    Type: Grant
    Filed: December 3, 2019
    Date of Patent: June 29, 2021
    Assignee: OKUMA CORPORATION
    Inventor: Motozumi Yura
  • Publication number: 20210190632
    Abstract: A feed axis diagnostic device for a machine tool is provided. The machine tool machines a workpiece while driving a moving body with feed axes along a guide surface of a rolling guide mechanism. The feed axis diagnostic device includes a feed axis diagnostic unit configured to detect an abnormality in the rolling guide mechanism in the machine tool. The feed axis diagnostic unit is configured to acquire a feed speed during non-machining and a load applied to the feed axes at the feed speed. The abnormality is detected based on an approximate function calculated from relationships between a plurality of the feed speeds and a plurality of the loads acquired under a plurality of different feed speed conditions in a predetermined period.
    Type: Application
    Filed: November 16, 2020
    Publication date: June 24, 2021
    Applicant: OKUMA CORPORATION
    Inventor: Takumi HONGO
  • Patent number: 11038409
    Abstract: A rotor of a synchronous motor includes a rotor core that includes magnet insertion holes and a plurality of slits formed on an outer peripheral side of the magnet insertion holes, and permanent magnets embedded in the magnet insertion holes. Magnetic-path forming slits are formed at intervals in a direction along a side of the permanent magnet. Magnetic paths are formed between the magnetic-path forming slits and at portions on the outside of the magnetic-path forming slits on the outermost side. An adjusting slit is formed between a predetermined magnetic-path forming slit and the permanent magnet such that a difference between quantities of magnetic flux passing through the magnetic paths adjacent to each other for widths in a direction intersecting an orientation of a magnetic pole of the permanent magnet is small.
    Type: Grant
    Filed: July 10, 2019
    Date of Patent: June 15, 2021
    Assignee: OKUMA CORPORATION
    Inventors: Tatsuya Shizu, Takanori Yokochi
  • Patent number: 11027417
    Abstract: A machine tool includes a workpiece spindle that retains a workpiece or a tool, a spindle motor that rotates the workpiece spindle, an in-machine robot that is provided inside the machine tool and that is an articulated robot having one or more joints, and a plurality of gears that connect or disconnect a root joint which is placed, among the one or more joints, closest to a base end, and the spindle motor to or from each other.
    Type: Grant
    Filed: February 28, 2018
    Date of Patent: June 8, 2021
    Assignee: OKUMA CORPORATION
    Inventor: Shoichi Morimura
  • Patent number: 11027390
    Abstract: A machine tool system includes a machine tool having a processing chamber covered by a cover and a door for covering or uncovering an opening formed on the cover; a stocker for being removably mounted on the machine tool to thereby define a storage space outside the processing chamber; and a robot having a movement range spanning the storage space and the processing chamber when the stocker is mounted on the machine tool. In the machine tool mentioned above, the stocker includes a safety fence that defines, in cooperation with the outer surface of the machine tool, a protective space when the stocker is mounted on the machine tool. The protective space is a space for accommodating the storage space.
    Type: Grant
    Filed: February 26, 2019
    Date of Patent: June 8, 2021
    Assignee: OKUMA CORPORATION
    Inventors: Hiroyuki Sugiura, Yosuke Ichigi
  • Publication number: 20210154791
    Abstract: An error measurement method for a machine tool measures an error in a machine tool that includes two or more translational axes, a table, and a spindle head. The error measurement method includes installing a masterwork having a plurality of targets on the table and detecting a position of each of the targets using a sensor mounted to the spindle head to acquire a measured value regarding the position of each of the targets and to acquire an error value regarding the position of each of the targets using each of the acquired measured values and a preliminarily acquired calibration value regarding the position of each of the targets. The error measurement method further includes calculating at least one disturbance index value indicative of a degree of disturbance in the measurement for each of the targets, and determining whether the disturbance index value exceeds a preliminarily set threshold.
    Type: Application
    Filed: October 26, 2020
    Publication date: May 27, 2021
    Applicant: OKUMA CORPORATION
    Inventors: Takuya KOJIMA, Tetsuya MATSUSHITA
  • Patent number: 11007656
    Abstract: A robot unit includes a robot main body that is an arm-type robot including multiple links connected to one another via at least one joint, and one or more protective housings that cover and protect at least a portion of a circumferential surface of one or more of the multiple links. One or more fastening portions that attach and detach the protective housing are provided on a circumferential surface of the one or more of the multiple links.
    Type: Grant
    Filed: September 16, 2019
    Date of Patent: May 18, 2021
    Assignee: OKUMA CORPORATION
    Inventor: Shoichi Morimura
  • Publication number: 20210140853
    Abstract: An abnormality diagnostic method for a feed axis device that diagnoses an abnormality of the feed axis device including a screw shaft and a nut, the feed axis device being incorporated in mechanical equipment, the abnormality diagnostic method includes controlling an operation of the feed axis device such that the screw shaft operates in a predetermined operating pattern, detecting a physical quantity signal generated from the feed axis device, and performing an abnormality diagnosis for the feed axis device based on the physical quantity signal detected by the detecting in accordance with a predetermined abnormality diagnosis algorithm. The performing includes performing a frequency analysis on the physical quantity signal to extract respective frequencies corresponding to a plurality of operating positions in the operating pattern and performing the abnormality diagnosis based on change of the frequencies corresponding to the respective operating positions.
    Type: Application
    Filed: October 2, 2020
    Publication date: May 13, 2021
    Applicant: OKUMA CORPORATION
    Inventors: Mariko ITO, Takumi HONGO
  • Publication number: 20210131783
    Abstract: A position measurement method includes, acquiring a sensing position of a distal end of a reference tool, measuring and acquiring a position of a machined surface, The method further includes measuring a position of a reference block disposed on a side of the tool sensor and calculating a relative position of the reference block to the sensing position from the sensing position and the position of the reference block, mounting the position measurement sensor to the main spindle and measuring a position of the reference block, calculating a length direction correction value of the position measurement sensor from the position of the reference block measured in the mounting of the position measurement sensor and the relative position, and measuring the object by the position measurement sensor and correcting a measurement position of the object.
    Type: Application
    Filed: October 22, 2020
    Publication date: May 6, 2021
    Applicant: OKUMA CORPORATION
    Inventor: Reiji KANBE
  • Publication number: 20210131789
    Abstract: A correction value measurement method includes, measuring a position of a reference sphere, calculating a relative position of the reference sphere with respect to a sensing position from the position of the reference sphere, a length of the position measurement sensor, and a length of the reference tool. The method further includes acquiring a reference tool position as a distal end position of the reference tool using, calculating a length direction correction value of the position measurement sensor from the reference tool position, the position of the reference sphere, the relative position, and a length of the reference tool, and measuring the position of the reference sphere to calculate a radial direction correction value of the position measurement sensor.
    Type: Application
    Filed: October 2, 2020
    Publication date: May 6, 2021
    Applicant: OKUMA CORPORATION
    Inventor: Reiji KANBE
  • Publication number: 20210132590
    Abstract: An error compensation method includes outputting at least one of a plurality of calibration-master conditions including a type of a calibration master that includes targets, obtaining measurement values of positions of the targets by detecting the positions of the plurality of targets under the calibration-master condition using a sensor mounted to the main spindle, and calculating an error value using the measurement value and a calibration value of the position of the target. The error compensation method further includes approximating a relation between the measurement values and the error values by a curve and a straight line, calculating a compensation parameter of a positioning error of a translational axis based on an approximate curve in a partial range of a stroke of the translational axis, and calculating the compensation parameter of the positioning error based on an approximate straight line in another range of the stroke of the translational axis.
    Type: Application
    Filed: October 22, 2020
    Publication date: May 6, 2021
    Applicant: OKUMA CORPORATION
    Inventors: Takuya KOJIMA, Tetsuya MATSUSHITA, Yasunori KONDO
  • Publication number: 20210132101
    Abstract: A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a variation value setting unit, a drawing unit, a first display unit, and a settable range calculating unit. The settable range calculating unit is configured to calculate a settable range of a variation amplitude and a variation cycle based on a calculation formula. The calculation formula includes the variation cycle, a difference between a first rotation speed and a second rotation speed at mutually different timings among the rotation speeds varied relative to a reference rotation speed, an inertia of a rotating body, a rated output of a motor that drives a main spindle, and a usage proportion to the rated output of the motor.
    Type: Application
    Filed: October 2, 2020
    Publication date: May 6, 2021
    Applicant: OKUMA CORPORATION
    Inventors: Shunsuke FUJIMAKI, Akihide HAMAGUCHI
  • Publication number: 20210132102
    Abstract: A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a drawing unit, a variation position display unit, and a reduction effect index display unit. The drawing unit is configured to display a variation diagram that illustrates a relationship between a variation amplitude and a variation cycle of the rotation speed. The reduction effect index display unit is configured to display a reduction effect index on the variation diagram. The reduction effect index represents a reduction effect of chatter vibration. The reduction effect index is calculated based on a speed ratio that is a ratio of a rotation speed of one rotation before to a rotation speed at an identical rotation position of the main spindle at any given timing.
    Type: Application
    Filed: October 2, 2020
    Publication date: May 6, 2021
    Applicant: OKUMA CORPORATION
    Inventors: Shunsuke FUJIMAKI, Akihide HAMAGUCHI
  • Publication number: 20210101241
    Abstract: A main spindle monitoring device determines an abnormality of a main spindle in a machine tool. The main spindle monitoring device includes a main spindle operation monitoring unit and a feed axis operation monitoring unit. The main spindle operation monitoring unit monitors a change of an operation condition of the main spindle based on a main spindle load. The feed axis operation monitoring unit monitors a change of an operation condition of a feed axis based on a feed axis load. The abnormality of the main spindle is determined when the main spindle operation monitoring unit detects the change of the operation condition of the main spindle and the feed axis operation monitoring unit does not detect the change of the operation condition of the feed axis in a state where a constant rotation speed is commanded to the main spindle while the feed axis is driving.
    Type: Application
    Filed: September 15, 2020
    Publication date: April 8, 2021
    Applicant: OKUMA CORPORATION
    Inventor: Takumi HONGO
  • Publication number: 20210088319
    Abstract: A tool cutting edge measuring device that is mounted on a horizontal lathe and multitasking machine includes contact type sensors and an arm. The sensors are configured to measure cutting edge positions of tools in a machining chamber and the arm is movable between an advance position and a retracted position. The arm advances into the machining chamber at the advance position and retracts from the machining chamber at the retracted position. The arm has distal ends provided with two branching units branched into the X-axis direction and the Z-axis direction at the advance position and the sensors are mounted to the respective branching units.
    Type: Application
    Filed: September 11, 2020
    Publication date: March 25, 2021
    Applicant: OKUMA CORPORATION
    Inventor: Shinya NARUSE
  • Publication number: 20210078124
    Abstract: Provided is an automated pallet changer in machine tool which enable miniaturization and cost reduction. A drive unit in the automatic pallet changer includes a planetary reduction gear. The planetary reduction gear has a first output shaft and a second output shaft in which, by fixing one of the first and second output shaft, the other functions as an output shaft for driving. The first output shaft is used to pivot the pivoting frame, and the second output shaft is used to move the carry-in/out arm back and forth.
    Type: Application
    Filed: September 11, 2020
    Publication date: March 18, 2021
    Applicant: OKUMA CORPORATION
    Inventor: Makoto Yoshida
  • Patent number: 10915088
    Abstract: An operating state display device displays an operating state of a feed axis in a machine tool including the feed axis. The feed axis linearly moves a moving body via a ball screw with a servomotor. The operating state display device includes a passage number count unit, a use frequency calculation unit, and a display unit. The passage number count unit preliminarily divides an operating range of an axis operation of the feed axis into a predetermined number of sections and counts passage numbers of the moving body in the respective sections. The use frequency calculation unit calculates frequencies of use in respective classified types of the axis operation in each of the sections based on the counted passage numbers. The display unit displays the calculated frequencies of use in the respective classified types on a monitor in a predetermined aspect.
    Type: Grant
    Filed: October 24, 2018
    Date of Patent: February 9, 2021
    Assignee: Okuma Corporation
    Inventor: Takumi Hongo