Patents Assigned to Okuma Corporation
  • Publication number: 20180120827
    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: Application
    Filed: September 12, 2017
    Publication date: May 3, 2018
    Applicant: Okuma Corporation
    Inventors: Takumi HONGO, Hitoshi SUMI
  • Publication number: 20180111238
    Abstract: A machine tool includes a base, a table, a main spindle, and a trunnion unit. The table is installed on the base. A tool is mounted to the main spindle. The main spindle is caused to approach a workpiece on the table along an up-down direction. The trunnion unit is configured to rotatably hold the table on which the workpiece is placed using a rotation axis along a front-rear direction as a center. The trunnion unit is disposed movable in a right-left direction.
    Type: Application
    Filed: September 12, 2017
    Publication date: April 26, 2018
    Applicant: Okuma Corporation
    Inventor: Koji Tsuchida
  • Patent number: 9952582
    Abstract: Maximum values of actual machining allowances of a workpiece in respective cutting flutes are averaged by control amounts of respective cutting flutes calculated by an arithmetic unit. The arithmetic unit converts the calculated control amounts into an amount in each axis direction and subtracts the value from a feed axis command value in an NC program stored in a storage unit. Then, a numeral value control unit performs machining by controlling respective feed axes based on the subtracted feed axis command value.
    Type: Grant
    Filed: September 1, 2015
    Date of Patent: April 24, 2018
    Assignee: Okuma Corporation
    Inventor: Hiroshi Inagaki
  • Patent number: 9952249
    Abstract: A torque command value and an acceleration detection value are accumulated when a driven portion is subjected to acceleration/deceleration driving, and, from a ratio between the two, inertia of a movable portion is calculated. By executing the acceleration/deceleration driving about a position where influence of gravity torque is zero, the influence of the gravity torque included in the torque command value before and after the center position is offset, whereby inertia can be estimated correctly even with a machine structure in which the influence of gravity differs depending on the position of the motor.
    Type: Grant
    Filed: April 25, 2014
    Date of Patent: April 24, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Masashi Miyaji
  • Patent number: 9933333
    Abstract: A bearing diagnostic device senses a failure in a bearing of a machine tool including a rotation shaft device. The bearing diagnostic device includes a rotation counting unit, a temperature measuring unit, a frictional torque calculating unit, a rolling speed calculating unit, a bearing characteristic calculating unit, a storage unit, and a determination unit. The frictional torque calculating unit is configured to calculate a frictional torque of the rotation shaft device. The rolling speed calculating unit is configured to calculate a rolling speed of the bearing from the count of rotations. The bearing characteristic calculating unit is configured to calculate a bearing characteristic from the frictional torque and the rolling speed. The determination unit is configured to compare the bearing characteristic calculated by the bearing characteristic calculating unit with a reference bearing characteristic stored in the storage unit to determine a presence of a failure.
    Type: Grant
    Filed: July 14, 2016
    Date of Patent: April 3, 2018
    Assignee: Okuma Corporation
    Inventors: Naoki Kawada, Issei Koike
  • Patent number: 9932979
    Abstract: An oil pressure control device for supplying oil pressure by rotating a hydraulic pump, by means of a motor, comprises an oil pressure sensor; a speed instruction operation unit for outputting a speed instruction value, based on a difference between an oil pressure determination value from the oil pressure sensor and an oil pressure instruction value; a torque instruction value operation unit for calculating a torque instruction value, based on a difference between a speed determination value and the speed instruction value; and a current control unit for controlling a current of the motor, based on the torque instruction value, and adds the load variation compensation speed outputted from the load variation compensation unit and the speed instruction value.
    Type: Grant
    Filed: November 14, 2014
    Date of Patent: April 3, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Tomohiro Shibata
  • Publication number: 20180071876
    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: Application
    Filed: August 9, 2017
    Publication date: March 15, 2018
    Applicant: Okuma Corporation
    Inventor: Takaaki TANAKA
  • Patent number: 9910422
    Abstract: An error identification method of a machine tool includes an initial position measurement step of indexing a main spindle head rotation axis to an initial angle to measure an initial position of a measured jig, a table reference angle calculation step of calculating a reference angle of the table, a reference position measurement step of indexing the table rotation axis to the reference angle and indexing the main spindle head rotation axis to the initial angle, a relative position measurement step of respectively indexing the table rotation axis and the main spindle head rotation axis to a plurality of predetermined angles, an arc approximation step of approximating the plurality of measured position values into an arc, and an error calculation step of calculating an error of a center position of the rotation axis, a tilt error of the rotation axis, or a tilt error of the translational axis.
    Type: Grant
    Filed: February 1, 2016
    Date of Patent: March 6, 2018
    Assignee: Okuma Corporation
    Inventor: Tetsuya Matsushita
  • Patent number: 9906184
    Abstract: A temperature detection element that detects a temperature of a detector is provided in a detector that detects a rotational position and/or a rotational speed of a rotor of a motor. An estimated value of a change of a wiring temperature is calculated based on a current supplied to the wiring of the motor. An estimated value of a change of the detector temperature is calculated based on the estimated value of the change of the wiring temperature. A difference between the detector temperature detected by the temperature detection element and the estimated value of the change of the detector temperature is set as an environmental temperature. The environmental temperature is added to the estimated value of the change of the wiring temperature, to estimate an absolute value of the wiring temperature. The wiring temperature is monitored based on the estimated absolute value of the wiring temperature.
    Type: Grant
    Filed: December 2, 2015
    Date of Patent: February 27, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Takahiko Yato
  • Patent number: 9906356
    Abstract: In a system including a master station, slave stations, and a loop communication path for connecting the master and slave stations, the master station measures for each of the slave stations a transmission lag time from transmission of a communication frame in a forward direction through a loop communication channel in the master station to reception of the communication frame returned in a backward direction from the slave station, and calculates timer correction times for the slave stations based on both the transmission lag times measured for the slave stations and delay time information representing delay times caused by communication frame processing in the slave stations. Each of the slave stations includes a transmission/reception switch which switches a communication frame transmitting/receiving direction between the forward and backward directions in the loop communication channel, to allow timer synchronization in the loop communication path formed by the single communication channel.
    Type: Grant
    Filed: December 8, 2016
    Date of Patent: February 27, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Tomohiro Shibata
  • Publication number: 20180043492
    Abstract: A bearing diagnostic device includes an identification unit and an obtaining unit. The identification unit is configured such that a feature quantity, an operation condition of a main spindle at a measurement of the feature quantity, and specification data of the bearing used for the main spindle are preliminarily configured as inputs. The identification unit is configured such that a normal state and an abnormal state are preliminarily configured as outputs. The identification unit is configured to create an identification model through machine learning. The obtaining unit is configured to obtain the feature quantity, the operation condition at the measurement of the feature quantity, and the specification data of the bearing used for the main spindle.
    Type: Application
    Filed: July 7, 2017
    Publication date: February 15, 2018
    Applicant: Okuma Corporation
    Inventor: Tomoharu ANDO
  • Publication number: 20180029185
    Abstract: An information measuring device includes a sensor that obtains information on a phenomenon periodically occurring on an apparatus while being synchronized with the steady repetition of an operation and a control device. The control device associates the obtained information with an operation phase in the operation so as to generate change in the phenomenon in one cycle based on the information obtained during the operation of several times. Meanwhile, an operation cycle where the operation is repeated in the apparatus, a sampling cycle, and a duration where the operation is steadily repeated in the apparatus are included in measurement parameters. The control device calculates an optimum measurement parameter from a relation between the measurement parameters on at least one of the measurement parameters and changes the measurement parameter as a target to the optimum measurement parameter.
    Type: Application
    Filed: July 20, 2017
    Publication date: February 1, 2018
    Applicant: Okuma Corporation
    Inventor: Takaaki TANAKA
  • Patent number: 9878414
    Abstract: A cutting fluid tank includes: a fluid ejection apparatus configured to eject fluid toward cutting fluid containing chips and to be capable of varying at least one of a direction and a position of ejection with time in an interior of a tank body configured to store the cutting fluid containing the chips flowed from a work portion of a machine tool. The fluid ejection apparatus includes an ejection head having an ejection port rotatable about an axis of rotation. The ejection port is at a twisted position with respect to the axis of rotation, and the ejection head is rotated by a reaction force of the fluid ejected from the ejection port. Part of the cutting fluid stored in the cutting fluid tank is used as the fluid to be ejected from the ejection port.
    Type: Grant
    Filed: December 21, 2015
    Date of Patent: January 30, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Shoichi Morimura
  • Publication number: 20180021904
    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: Application
    Filed: June 22, 2017
    Publication date: January 25, 2018
    Applicant: Okuma Corporation
    Inventors: Issei KOIKE, Naoki Kawada
  • Patent number: 9873173
    Abstract: A cutting fluid tank includes a variable flow restricting device configured to restrict a flow of cutting fluid containing chips into an interior of a tank body configured to store the cutting fluid containing the chips flowed from a work portion of a machine tool. The variable flow restricting device includes variable partitioning members which constitute at least part of a partitioning that partitions a flow channel of the cutting fluid containing the chips. The variable partitioning member is pivotably and the flow channel varies in association with the pivotal motion of the variable partitioning member.
    Type: Grant
    Filed: December 21, 2015
    Date of Patent: January 23, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Shoichi Morimura
  • Patent number: 9876448
    Abstract: A tandem control method is applied to a position control apparatus. The tandem control method controls one object to be controlled by individually driving a first driving shaft and a second driving shaft. A speed difference between the first driving shaft and the object to be controlled is amplified and added to a torque command value of the first driving shaft. A speed difference between the second driving shaft and the object to be controlled is amplified and added to a torque command value of the second driving shaft.
    Type: Grant
    Filed: August 19, 2015
    Date of Patent: January 23, 2018
    Assignee: OKUMA CORPORATION
    Inventor: Satoshi Eguchi
  • Patent number: 9839982
    Abstract: A main spindle load monitoring device indicates a main spindle load in a machine tool that includes a tool with a plurality of edges on a main spindle and performs a process of a workpiece while the tool rotates with the main spindle. The main spindle load monitoring device includes a main spindle load detecting unit configured to detect a load on the main spindle, a main spindle load conversion unit, and a display control unit. The main spindle load conversion unit is configured to convert a time course of the main spindle load detected by the main spindle load detecting unit into a change of the main spindle load with respect to a main spindle rotation angle. The display control unit is configured to indicate a value of the main spindle load converted by the main spindle load conversion unit on a display screen in a polar coordinates system.
    Type: Grant
    Filed: June 15, 2016
    Date of Patent: December 12, 2017
    Assignee: Okuma Corporation
    Inventor: Tomoharu Ando
  • Patent number: 9829500
    Abstract: 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?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)?P(t?nT)|>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.
    Type: Grant
    Filed: October 16, 2012
    Date of Patent: November 28, 2017
    Assignee: OKUMA Corporation
    Inventor: Yasukazu Hayashi
  • Patent number: 9804584
    Abstract: A disturbance suppressing system is incorporated in a servo control apparatus. In the disturbance suppressing system, a component e introduced in an output of a target plant due to a disturbance estimate error is amplified in a disturbance suppressing controller having a frequency characteristic corresponding to a magnitude of a plant error, which is a difference in transfer characteristics between the target plant and the plant model, and the amplified component e is fed back to a control input.
    Type: Grant
    Filed: September 1, 2015
    Date of Patent: October 31, 2017
    Assignee: OKUMA CORPORATION
    Inventor: Satoshi Eguchi
  • Publication number: 20170297160
    Abstract: An error identification method includes a tool sensor position acquisition stage, a reference block position acquisition stage, a relative position calculation stage, a reference tool position acquisition stage, a position measurement sensor measurement stage, a length compensation value calculation stage, a diameter compensation value acquisition stage, a position measurement stage, a position compensation stage, and a geometric error identification stage. The diameter compensation value acquisition stage acquires a radial direction compensation value of the position measurement sensor with the measured jig. The position measurement stage indexes the rotation axis to a plurality of any given angles and measures respective positions of the measured jig. The position compensation stage compensates the position measurement value at the position measurement stage using the length direction compensation value and the radial direction compensation value.
    Type: Application
    Filed: April 11, 2017
    Publication date: October 19, 2017
    Applicant: Okuma Corporation
    Inventors: Tetsuya MATSUSHITA, Reiji KANBE