Patents Assigned to Okúma Corporation
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Patent number: 10760994Abstract: 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: GrantFiled: July 19, 2017Date of Patent: September 1, 2020Assignee: Okuma CorporationInventor: Takumi Hongo
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Patent number: 10737333Abstract: A machine tool includes: a turret configured to hold a tool through a clamp mechanism; a workpiece main spindle device configured to rotatably hold a workpiece; a switching unit configured to change a clamp state of the clamp mechanism by using rotation torque of the workpiece main spindle device; and an in-machine robot configured to move the switching unit. The clamp mechanism includes a torque input hole to which rotation torque is applied to change the clamp state. The switching unit includes an input shaft coupled with the workpiece main spindle device, an output shaft coupled with the torque input hole of the clamp mechanism and configured to output torque to the torque input hole, and a transmission mechanism configured to transfer, to the output shaft, the rotation torque of the workpiece main spindle device input through the input shaft.Type: GrantFiled: January 23, 2019Date of Patent: August 11, 2020Assignee: OKUMA CORPORATIONInventors: Tomoki Hayashi, Shoichi Morimura
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Patent number: 10725465Abstract: A state diagnostic device collects a usage state and diagnostic data of components, and selects, from the collected diagnostic data, at least one of diagnostic data obtained in a state where the usage state of the components is a truly normal state and diagnostic data obtained in a state where the usage state of the components is a truly abnormal state. The selected diagnostic data is defined as master data. A diagnosis result obtained by diagnosing the master data based on a current diagnostic model is compared with a diagnosis result obtained by diagnosing the master data based on a new diagnostic model, and whether the current diagnostic model is consistent with the new diagnostic model is determined. When the consistency is satisfied, the diagnostic model is updated from the current diagnostic model to the new diagnostic model.Type: GrantFiled: February 21, 2018Date of Patent: July 28, 2020Assignee: Okuma CorporationInventors: Takahiro Tamakoshi, Hiroshi Ueno, Tomoharu Ando
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Publication number: 20200230764Abstract: A method includes four steps, (1) setting an initial tool temperature, (2) estimating a temperature of a tool or a position measurement sensor based on the initial tool temperature and a temperature of a spindle, (3) estimating an amount of thermal displacement of the tool or the position measurement sensor with a preliminarily set tool thermal displacement estimation formula based on the estimated temperature, and (4) moving a feed shaft of the machine tool based on the estimated amount of thermal displacement to perform a correction. In the second step, the temperature of the spindle is measured, then a tool-mounted portion temperature of the spindle from the measured temperature is estimated. Further, the temperature of the tool or the position measurement sensor is estimated with the tool-mounted portion temperature, the initial tool temperature of the tool or the position measurement sensor, and the preliminarily set tool temperature estimation formula.Type: ApplicationFiled: December 24, 2019Publication date: July 23, 2020Applicant: OKUMA CORPORATIONInventor: Yuji MIZOGUCHI
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Patent number: 10702962Abstract: A swarf handling apparatus installed in a machining tool that performs machining operation accompanied with production of stringy swarf includes a swarf catching device. The swarf catching device includes a holder unit that holds the stringy swarf when the stringy swarf makes contact with the holder unit. The swarf catching device causes the holder unit to be floated in a region around a machining point in such a manner that the position of the holder unit is varied relative to the machining point, for catching the stringy swarf in the holder unit.Type: GrantFiled: April 27, 2018Date of Patent: July 7, 2020Assignee: OKUMA CORPORATIONInventor: Hiroyuki Sugiura
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Patent number: 10688612Abstract: A machine tool is provided which can execute various works while suppressing increase in cost or size. The machine tool includes a tool spindle device which is a movable member which can move with respect to a mounting surface of the machine tool, and one or more serial-manipulator-type robots attached on the tool spindle device, which can move with the tool spindle device, and which have two or more degrees of freedom, and the robot includes two or more end effectors provided at positions different from each other with one or more joints therebetween.Type: GrantFiled: May 12, 2017Date of Patent: June 23, 2020Assignee: OKUMA CORPORATIONInventor: Shoichi Morimura
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Patent number: 10663942Abstract: A position control apparatus includes an inversion detector which detects an inversion of a position command and generates an inversion detection signal, a deflection characteristic storage unit which stores a deflection characteristic representing an amount of deflection with respect to a torque command, and an inversion correction calculator which calculates an inversion correction amount. The inversion correction calculator stores a torque command immediately before the inversion, and calculates the inversion correction amount from a difference between an amount of deflection immediately before inversion in which the stored torque command is checked with the deflection characteristic, and an amount of deflection after the inversion in which a value obtained by inverting a sign of the stored torque command is checked with the deflection characteristic. A value obtained by adding the inversion correction amount to the position command value is used for position error calculation.Type: GrantFiled: July 26, 2018Date of Patent: May 26, 2020Assignee: OKUMA CORPORATIONInventors: Hisashi Kondou, Tomohiro Shibata, Yuji Uchida, Takeshi Sakai
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Patent number: 10649014Abstract: A method measures a frequency characteristic at a feed axis control unit configured to drive a motor in accordance with a velocity command value to control a velocity or a position of a movable portion of a driven body. The velocity command value includes a velocity reference value from a host device or a velocity command calculator and a sweep signal swept in order to measure the frequency characteristic. The method includes moving the feed axis in one direction by commanding the velocity reference value where a moving velocity of the feed axis is constant, exciting by providing a sine wave having an amplitude less than a magnitude of the velocity reference value to the sweep signal, and measuring the frequency characteristic of a feed axis drive system including the motor.Type: GrantFiled: February 23, 2017Date of Patent: May 12, 2020Assignee: Okuma CorporationInventors: Masashi Miyaji, Takashi Norihisa
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Patent number: 10632611Abstract: The machine tool includes a tool post linearly movable along a direction parallel to an X axis and a direction parallel to a Z axis, a workpiece spindle which retains a workpiece in a condition rotatable about an axis parallel to the Z axis, and an in-machine robot which is installed in a machining chamber and has joints. The joints of the in-machine robot include a base joint rotatable about an axis parallel to the Z axis, and three parallel joints rotatable about an axis orthogonal to the axis of rotation of the base joint, the parallel joints being located on a distal end side of the base joint and successively arranged from the base joint. The axis of rotation of the base joint is displaced from that of the workpiece spindle.Type: GrantFiled: December 3, 2018Date of Patent: April 28, 2020Assignee: OKUMA CORPORATIONInventor: Shoichi Morimura
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Patent number: 10603752Abstract: A machine tool that cuts a workpiece by a rotary tool includes a tool spindle device that holds the rotary tool in a manner to allow self-rotation with a predefined tool rotational axis Rt as a center, one or more in-machine robots, and a connecting mechanism that attaches the in-machine robot on the tool spindle device so that the in-machine robot moves independently from the rotary tool at a periphery of the tool spindle device with the tool rotational axis Rt as a center.Type: GrantFiled: April 28, 2017Date of Patent: March 31, 2020Assignee: OKUMA CORPORATIONInventor: Shoichi Morimura
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Patent number: 10594242Abstract: A controller for a motor determines a voltage limit circle based on a velocity of the motor, a DC bus voltage of an inverter, calculates a q axis current limit value based on the voltage limit circle and a predetermined current limit circle, determines, as a q axis current command value, a value obtained through a limit process which is applied using the q axis current limit value to a q axis current value calculated in accordance with a torque command value, and determines a corresponding d axis current value based on the q axis current command value.Type: GrantFiled: January 30, 2019Date of Patent: March 17, 2020Assignee: OKUMA CORPORATIONInventor: Satoshi Eguchi
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Patent number: 10585416Abstract: 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: GrantFiled: October 24, 2018Date of Patent: March 10, 2020Assignee: Okuma CorporationInventor: Takumi Hongo
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Patent number: 10578723Abstract: In a position detector for converting, into position information, two signals shifted in phase by 90 degrees from each other, a phase correction value calculator for calculating a phase correction value for correcting a phase difference between the two signals calculates a phase change value representing a change in the phase correction value, to find a next phase correction value based on the phase change value and a present phase correction value. A virtual change value calculator calculates, based on second-order components obtained by Fourier analysis of a radius value, a virtual phase change value representing another change in the phase correction value obtained when changes in offset and amplitude ratio are ignored, and a virtual amplitude change value representing a change rate in an amplitude ratio correction value obtained when a change in the phase difference is ignored.Type: GrantFiled: June 13, 2017Date of Patent: March 3, 2020Assignee: OKUMA CORPORATIONInventor: Katsutoshi Iwazawa
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Patent number: 10545033Abstract: 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.Type: GrantFiled: May 19, 2016Date of Patent: January 28, 2020Assignee: OKUMA CORPORATIONInventors: Yasukazu Hayashi, Koji Kitagawa, Yasunori Kawakami, Hiroaki Matsuura
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Patent number: 10513001Abstract: 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: GrantFiled: July 7, 2017Date of Patent: December 24, 2019Assignee: Okuma CorporationInventor: Tomoharu Ando
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Patent number: 10496072Abstract: A temperature of a portion of which the temperature is difficult to directly measure is accurately estimated in a simple method. In S1, information about a coolant discharging/stopping state is obtained. As the information about the coolant discharging/stopping state, a flag is used such that the flag represents 1 for the discharging state and the flag represents 0 for the stopping state. Next, in S2, temperature data is obtained from temperature sensors provided in components of a machine tool, a machining space, and a coolant tank. Next, in S3, lag process is performed for the coolant discharging/stopping state flag, and coefficients for measured temperatures of the coolant and the structure are calculated. Next, in S4, the measured temperatures are multiplied by the coefficients, and an estimated temperature of a portion to which the temperature sensor is not attached is calculated.Type: GrantFiled: November 3, 2017Date of Patent: December 3, 2019Assignee: Okuma CorporationInventor: Yuji Mizoguchi
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Patent number: 10468924Abstract: A rotor for a flux-barrier-type reluctance motor having a plurality of poles formed in a circumferential direction includes a plurality of slits provided for each pole, a permanent magnet partially inserted into the slits in such a manner that magnetic poles of the permanent magnet are directed substantially orthogonal to the slit, a slit for a movable element disposed radially inside the permanent magnet disposed at an innermost position in a radial direction, and a movable element made of a magnetic material and inserted into the cavity, the movable element being capable of moving in the slit for the movable element in the circumferential direction. A radially inner side of the innermost slit into which the permanent magnet is inserted and radially outer and inner sides of both the slit for the movable element and the movable element are in a concentric circular-arc shape.Type: GrantFiled: May 4, 2017Date of Patent: November 5, 2019Assignee: OKUMA CORPORATIONInventor: Takanori Yokochi
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Publication number: 20190301975Abstract: A method for diagnosing an abnormality of rolling bearing includes: measuring a vibration of a rotator; performing a frequency analysis on the vibration to calculate a magnitude of a vibration at each frequency; calculating a characteristic frequency as a frequency of a vibration from a specification of the rolling bearing and a rotation speed of the rotator at a vibration measurement in the measuring; calculating a vibration value from which an effect of the rotation speed is removed by dividing a magnitude of a vibration at the characteristic frequency by a value including a base and an exponent, the base being a predetermined physical quantity in a proportional relation with an angular velocity of the rotator at the vibration measurement in the measuring, the exponent being a positive number; calculating an evaluation index based on the vibration value; and determining an existence of an abnormality based on the evaluation index.Type: ApplicationFiled: March 25, 2019Publication date: October 3, 2019Applicant: OKUMA CORPORATIONInventors: Hiraku SUGIURA, Issei KOIKE
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Patent number: 10409267Abstract: A main spindle controller of a machine tool varies a rotation speed of a main spindle that grips a workpiece to a varied maximum speed higher than a reference rotation speed set value as a set value of a reference rotation speed by a variation width set value as a set value of a variation width or a varied minimum speed lower than the reference rotation speed set value by the variation width set value in units of the tool path. At the same time, the main spindle controller refers to speed condition information that indicates a condition of the preliminarily stored reference rotation speed and variation width assuming that a chatter vibration is to be reduced, and when at least one of the reference rotation speed set value and the variation width set value does not satisfy the condition of the speed condition information.Type: GrantFiled: October 21, 2016Date of Patent: September 10, 2019Assignee: Okuma CorporationInventor: Kohei Nishimura
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Patent number: 10391559Abstract: A machine tool includes a workpiece spindle device which rotates a workpiece, a tool post which can move a tool in a first axis direction (X-axis direction) which is a radial direction of the workpiece and a second axis direction (Z-axis direction) which is an axial direction of the workpiece, and an articulated robot including a plurality of arms, a plurality of joints, and end effectors. The plurality of joints connect the plurality of arms in a rotatable manner around an axis parallel to a third axis (Y-axis) orthogonal to the first axis and the second axis, and the end effectors move in a plane parallel to a movement plane of the tool.Type: GrantFiled: May 24, 2017Date of Patent: August 27, 2019Assignee: OKUMA CORPORATIONInventor: Shoichi Morimura