Patents Assigned to Okuma Corporation
  • Patent number: 10310494
    Abstract: A diagnostic result display method in a diagnostic device calculates a diagnostic result by a determination of a predetermined state and a certainty factor of the determination. The diagnostic result display method includes setting preset predetermined colors to predetermined states, setting a preset area of a geometric shape according to certainty factors, and displaying the area of the geometric shape in at least one of the predetermined colors.
    Type: Grant
    Filed: September 12, 2017
    Date of Patent: June 4, 2019
    Assignee: Okuma Corporation
    Inventors: Takumi Hongo, Hitoshi Sumi
  • Patent number: 10307877
    Abstract: A machine tool that machines a workpiece by a tool includes a workpiece spindle device that holds the workpiece in a rotatable manner with a predefined workpiece rotational axis Rw as a center, one or more in-machine robots, and a connecting mechanism that attaches the one or more robots on the machine tool so that the one or more robots move independently from the workpiece, with the workpiece rotational axis Rw serving as a center.
    Type: Grant
    Filed: April 28, 2017
    Date of Patent: June 4, 2019
    Assignee: OKUMA CORPORATION
    Inventor: Shoichi Morimura
  • Publication number: 20190163164
    Abstract: An abnormality diagnostic method executes causing the feed axis to perform an axis operation in a predetermined diagnosis condition to obtain servo information according to a control of the servomotor, performing a frequency analysis on the obtained servo information, obtaining a damage frequency generated while the feed axis whose bearing is damaged performs the axis operation, from a result of the frequency analysis, and comparing the obtained damage frequency with a predetermined threshold to determine a presence/absence of an abnormality. In the determining, before the damage frequency is compared with the threshold, a determination whether a vibration frequency of the bearing interferes with a vibration frequency generated while a rolling element passes through a nut of the ball screw or not is performed, and the comparison is performed by setting the respective thresholds that are different in a case of the interference and a case of no interference.
    Type: Application
    Filed: October 24, 2018
    Publication date: May 30, 2019
    Applicant: OKUMA CORPORATION
    Inventor: Takumi HONGO
  • Patent number: 10302511
    Abstract: A method for determining a cogging torque may include applying a substantially constant rotation torque to an output shaft of a motor without electrically energizing the motor; detecting, an angle of rotation of the output shaft of the motor at each of a plurality of angles of rotation; calculating an angular acceleration of the motor at each of the plurality of angles of rotation by second order differentiating the angle of rotation; calculating a measured torque value at each of the plurality of angles of rotation by multiplying the angular acceleration by a moment of inertia of a rotor in the motor; obtaining a measured torque waveform of the measured torque value at each of the plurality of angles of rotation as a function of the plurality of angles of rotation; and calculating a cogging torque waveform based on a frequency of the measured torque waveform.
    Type: Grant
    Filed: December 9, 2015
    Date of Patent: May 28, 2019
    Assignee: OKUMA CORPORATION
    Inventor: Tatsuya Shizu
  • Publication number: 20190146454
    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: Application
    Filed: October 24, 2018
    Publication date: May 16, 2019
    Applicant: OKUMA CORPORATION
    Inventor: Takumi Hongo
  • Patent number: 10265818
    Abstract: In a machine tool, when machining is in a steady zone, a rotation phase of a main spindle at the time of measurement in the N-th sampling is calculated, and the calculated rotation phase and the measurement value are recorded in a recording section so as to be associated with each other. The measurement and calculation of the rotation phase of the main spindle at the time of each measurement are continued for plural times of rotations of the main spindle, and thus the measurement values are obtained at various rotation phases, whereby change in drive force during one rotation of the main spindle is finally calculated.
    Type: Grant
    Filed: August 9, 2017
    Date of Patent: April 23, 2019
    Assignee: Okuma Corporation
    Inventor: Takaaki Tanaka
  • Patent number: 10245697
    Abstract: A method for controlling a temperature adjustment system of a machine tool is provided. With the method, a temperature rise value ?Tk of a main spindle device after stopping of rotation of a main spindle is obtained by using a reference temperature measured by a machine body temperature sensor mounted in a portion other than the main spindle device of a machine tool to calculate an estimated temperature yk. Therefore, as compared to a conventional method based only on a temperature of a cooling medium, supply of the cooling medium by a cooling device can be stopped or an operation of the cooling device can be switched from a first mode to a second mode without deteriorating machining accuracy in the main spindle device, thereby efficiently reducing power consumption.
    Type: Grant
    Filed: October 13, 2015
    Date of Patent: April 2, 2019
    Assignee: Okuma Corporation
    Inventors: Eisuke Sogabe, Seiei Yamamoto
  • Publication number: 20190084112
    Abstract: A numerical control device for a machine tool controls a machine tool having a main spindle for attaching a tool, a table holding a workpiece and a jig, three translational axes, and one or more rotation axis. The numerical control device includes an axis-dependent deformation error estimation unit, an input unit, a gravitational deformation estimation unit, a correction value calculation unit, and an addition unit. The correction value calculation unit calculates a correction value of the translational axes and/or the rotation axis with respect to an error of a position and/or a posture of the tool with respect to the workpiece, based on an estimated value of an axis-dependent deformation error, an estimated value of a gravitational deformation error, and command values. The addition unit adds the correction values to the command values.
    Type: Application
    Filed: August 27, 2018
    Publication date: March 21, 2019
    Applicant: OKUMA CORPORATION
    Inventors: Takuya KOJIMA, Tetsuya MATSUSHITA
  • Publication number: 20190079489
    Abstract: A machining simulation apparatus performs a machining simulation in a machine tool by controlling a relative position between a tool model and a material model to perform a machining of the material model with the tool model. The machining simulation is performed with an input of at least one of a position command and a position detection value. The position command and the position detection value are obtained from the machine tool as log data corresponding to a time. A result of the machining simulation is displayed.
    Type: Application
    Filed: August 27, 2018
    Publication date: March 14, 2019
    Applicant: OKUMA CORPORATION
    Inventors: Keishi NATSUHARA, Daichi TATEBE, Katsunori KUNIMITSU
  • Patent number: 10228677
    Abstract: A vibration information display device includes a monitor, a vibration information acquisition unit, an operating information acquisition unit, a storage unit, and a display control unit. The monitor displays information on the chatter vibrations. The vibration information acquisition unit acquires vibration information when the chatter vibrations are detected. The operating information acquisition unit acquires operating information of the machine tool when the chatter vibrations are detected. The storage unit stores the acquired vibration information and operating information. The display control unit displays the vibration information and the operating information stored in the storage unit on the monitor. Alternatively, the display control unit displays the vibration information stored in the storage unit on the monitor together with trajectory information of a blade edge of the tool included in the operating information.
    Type: Grant
    Filed: April 13, 2016
    Date of Patent: March 12, 2019
    Assignee: Okuma Corporation
    Inventor: Tomoharu Ando
  • Patent number: 10209107
    Abstract: A geometric error identification method of multi-axis machine tool includes a measuring step of indexing a position of a target ball mounted on one of a main spindle and a table into a plurality of angles around an rotation axis, and measuring the position of the target ball at respective indexed positions by using a touch probe mounted on the other one of the main spindle and the table, a geometric error calculation step of calculating a geometric error from the measured position of the target ball, an ellipse-expression calculation step of calculating an ellipse approximate expression by an arc trajectory measured by operating the rotation axis, and an error correcting step of calculating and correcting a scaling error of translation axes from the calculated ellipse approximate expression.
    Type: Grant
    Filed: October 27, 2014
    Date of Patent: February 19, 2019
    Assignee: Okuma Corporation
    Inventor: Tadahiro Oki
  • Patent number: 10180164
    Abstract: A resolver for a rotation position detection device comprises a rotor portion having a resin gear having a hole formed at a center portion thereof through which a stationary shaft passes, and a rotor core connected to the resin gear; and a stator portion having the stationary shaft, an excitation wiring and a detection wiring, a back core, and a resin housing, wherein the excitation wiring and the detection wiring are arranged around the stationary shaft at a constant distance from the stationary shaft in a diameter direction, the back core is adjacent to or in contact with the stationary shaft, and the resin gear has a shape whose central portion projects in the shaft direction so as to be in contact with the back core.
    Type: Grant
    Filed: September 9, 2016
    Date of Patent: January 15, 2019
    Assignee: OKUMA CORPORATION
    Inventors: Shinji Shibata, Yasunori Kawakami
  • Publication number: 20190003924
    Abstract: It is an object to perform an abnormality diagnosis for a feed axis without additionally adding a sensor or the like. A frequency characteristic of a feed axis and a damage frequency that occurs when the feed axis that has been damaged performs an axis operation are obtained, a frequency where a gain is maximized in the obtained frequency characteristic is calculated, and a feed velocity where the frequency matches the damage frequency is calculated. An axis operation is performed on the feed axis with the calculated feed velocity, and a frequency analysis is performed on servo information regarding a control of a servo motor during the axis operation. Then, the presence and absence of a peak of the damage frequency is confirmed from a result of the frequency analysis, and when the peak is present, it is determined that it is abnormal.
    Type: Application
    Filed: July 19, 2017
    Publication date: January 3, 2019
    Applicant: OKUMA CORPORATION
    Inventor: Takumi HONGO
  • Publication number: 20190001453
    Abstract: A machine tool includes a shielding cover, a door, and an automatic tool changer. The shielding cover covers a machining space of a main spindle. The door opens and closes an opening disposed in the shielding cover. The automatic tool changer automatically exchanges a tool to be mounted to the main spindle. The automatic tool changer exchanges the tool to be mounted to the main spindle by turning an arm in a plane perpendicular to the main spindle so as to cause the arm to enter into and exit from the machining space. The arm is configured to grip and release the tool. The turning of the arm is synchronized with the opening and closing movement of the door.
    Type: Application
    Filed: April 27, 2018
    Publication date: January 3, 2019
    Applicant: OKUMA CORPORATION
    Inventor: Masanori ISHIKAWA
  • Patent number: 10145419
    Abstract: Provided is a bearing lubrication structure for a rotation unit having a bearing that is of a grease lubrication type in which the bearing is provided at both sides thereof with a seal structure, wherein the grease lubrication performance is improved. The bearing is provided on both sides thereof with fixed-side seal portions, and rotating side seal portions that are opposed thereto, respectively. The fixed-side seal portion is provided with a shield. The distance from the inner periphery of the shield to the axis of the rotary shaft varies depending on the location of a point on the inner periphery. The shield, which is one of the two shields, and the shield, which is the other one, are arranged so as not to have plane symmetry.
    Type: Grant
    Filed: June 28, 2017
    Date of Patent: December 4, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Shoichi Morimura
  • Patent number: 10137547
    Abstract: A main spindle device for a machine tool includes a main spindle, a cushioning member, and an arithmetic unit. The cushioning member is disposed on a position where a vibration displacement of a rotator exists. The arithmetic unit uses data of a tool to be used to analyze a vibration mode in a free vibration of the rotator based on a support rigidity of a bearing, masses of respective parts of the rotator including the tool, an attenuation coefficient, and an equation of motion derived from rigidity and inertia by a rotation. An outer diameter of a sleeve positioned outside the bearing is changed such that a position of an antinode of the vibration or a position on which a vibration displacement exists in the vibration mode matches a position of the cushioning member inside the main spindle to change a preload on the bearing.
    Type: Grant
    Filed: June 22, 2017
    Date of Patent: November 27, 2018
    Assignee: Okuma Corporation
    Inventors: Issei Koike, Naoki Kawada
  • Patent number: 10135382
    Abstract: A motor control device calculates a velocity difference based on a velocity command and a velocity detection value of a motor and an excitation current common phase voltage difference based on an excitation current command value and an excitation current detection value, and judges that demagnetization occurs when the following conditions are all met: the excitation current common phase voltage difference exceeds a voltage threshold; the velocity difference exceeds a velocity threshold; and acceleration is being performed.
    Type: Grant
    Filed: December 22, 2016
    Date of Patent: November 20, 2018
    Assignee: OKUMA CORPORATION
    Inventors: Tomohiro Shibata, Yoshimaro Hanaki
  • Patent number: 10092988
    Abstract: A tool pot includes a resin-made pot body and a metallic reinforcing member embedded in the pot body by insert molding. The reinforcing member is provided with a reinforcing plate embedded in a portion including a horizontal pin insertion portion in the pot body. The reinforcing plate is provided with a lightening hole so as to avoid the horizontal pin insertion portion.
    Type: Grant
    Filed: October 30, 2015
    Date of Patent: October 9, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Naoki Kawada
  • Patent number: 10088828
    Abstract: A numerical control device with a function to prevent a problem caused by a rapid stop of a processing operation due to a motor overheating during processing. A temperature comparator obtains a load ratio T/Tmax or Tw/Tmax which is a ratio of the motor temperature T or predicted temperature Tw to a maximum allowable temperature Tmax stored in a storage device. When the load ratio T/Tmax or Tw/Tmax is over a threshold Tp stored in a storage, the device is placed in an alarm mode to shutdown the power supply to the motor after the processing program is executed to the end of a sequence block or the end of the processing program.
    Type: Grant
    Filed: October 21, 2015
    Date of Patent: October 2, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Yoichi Kawai
  • Patent number: 10081088
    Abstract: A main spindle failure detection device for a machine tool includes a rotation speed detection unit, a reach time estimation unit, and a determining unit. The reach time estimation unit is configured to estimate a reach time in which the rotation speed of the main spindle reaches a predetermined rotation speed threshold using a non-linear model based on a rotation speed of the main spindle detected at a start of an inertia operation and a rotation speed of the main spindle detected after an elapse of preset measurement time from the start of the inertia operation. The determining unit is configured to compare the reach time estimated by the reach time estimation unit with a preset reach time in which the rotation speed reaches the rotation speed threshold, so as to determine a failure in the main spindle based on a result of the comparison.
    Type: Grant
    Filed: September 16, 2016
    Date of Patent: September 25, 2018
    Assignee: Okuma Corporation
    Inventors: Seiei Yamamoto, Naoki Kawada