Patents Assigned to Okuma Corporation
  • Patent number: 8899889
    Abstract: A table unit for a machine tool includes a tilting table provided on a base and configured to be swingably indexable around a horizontal axis, a rotary table provided on the tilting table and configured to be rotatably indexable around a vertical axis orthogonal to the horizontal axis, and at least one motor disposed in the tilting table and configured to be driven to rotate the rotary table. An axis of a motor shaft of the motor is arranged in a plane formed by the horizontal axis and the vertical axis.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: December 2, 2014
    Assignee: Okuma Corporation
    Inventor: Makoto Yoshida
  • Publication number: 20140320057
    Abstract: A position controller sets a variable friction compensation value which varies in accordance with a change in sliding characteristics by providing a variable friction compensation value calculation unit that includes a sliding torque normalization calculation unit that normalizes a sliding torque at a predefined speed; a compensation value amplifying ratio calculation unit that calculates a compensation value amplifying ratio based on the sliding torque at the normalized speed; and multipliers.
    Type: Application
    Filed: April 24, 2014
    Publication date: October 30, 2014
    Applicant: OKUMA Corporation
    Inventors: Masahiro Maeda, Satoshi Eguchi
  • Publication number: 20140318246
    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: Application
    Filed: April 25, 2014
    Publication date: October 30, 2014
    Applicant: OKUMA Corporation
    Inventor: Masashi Miyaji
  • Publication number: 20140318019
    Abstract: A door mechanism of a machining center includes a wide door panel, narrow door panels, a pair of upper and lower slide rails with a U-shaped section into which the wide door panel and the narrow door panels are to be fitted, three motors that serve as drive units for independently driving the wide door panel and the narrow door panels. The wide door panel and the narrow door panels are arranged in line so as to be slidable in the width direction such that an opening portion is opened and closed, and the opening width has a length suitable for the length of the largest workpiece on one pallet.
    Type: Application
    Filed: March 19, 2014
    Publication date: October 30, 2014
    Applicant: Okuma Corporation
    Inventors: Tomofumi TSUCHIDA, Makoto TOMITA
  • Publication number: 20140312548
    Abstract: A machine tool includes a slide table supported by an upper portion of a main body of the machine tool so as to be horizontally slidable, a rotary table provided on the slide table so as to be rotationally indexable about a vertical axis extending in the direction that is orthogonal to the direction of horizontal slide movement of the slide table, and a motor provided in the slide table to rotate the rotary table. A housing space is formed in the main body to house a lower portion of the slide table. At least a part of the motor provided in the slide table is placed in the housing space.
    Type: Application
    Filed: March 11, 2014
    Publication date: October 23, 2014
    Applicant: Okuma Corporation
    Inventor: Makoto YOSHIDA
  • Publication number: 20140309766
    Abstract: A numeric controller is provided with a three-dimensional model storage which stores a three-dimensional model of at least one of a workpiece and a jig; a three-dimensional measuring unit which integrally measures shapes of the workpiece and the jig fixed to the machine tool; and a shape processor generating an integrally measured model based on the measured data, in which the workpiece and the jig being integrally recognized, measured by the three-dimensional measuring unit, and further generating, regarding at least one of the workpiece and the jig, an individually measured model in which the workpiece or the jig is individually measured based on the generated integrally measured model and the three-dimensional model of the workpiece or the jig.
    Type: Application
    Filed: April 15, 2014
    Publication date: October 16, 2014
    Applicant: OKUMA Corporation
    Inventors: Katsunori Kunimitsu, Masayuki Sugie
  • Publication number: 20140306644
    Abstract: An electric motor control device for performing tandem control for driving one movable component includes, for each electric motor, a position controller, a speed controller, and a current controller. Further, each electric motor also has a preload controller for adding a preload torque to a torque command Tm calculated by the speed controller, and to a torque command Ts calculated by the speed controller. The preload controller calculates a minimum necessary preload torque for eliminating backlash in accordance with a position of the movable component.
    Type: Application
    Filed: April 11, 2014
    Publication date: October 16, 2014
    Applicant: OKUMA Corporation
    Inventors: Takeshi Sakai, Akiyoshi Satake
  • Patent number: 8862429
    Abstract: At least a rotation speed of a rotary shaft and a vibration acceleration in a frequency domain are stored as an operating history, and the operating history is stored not only when the rotation speed of the rotary shaft varies, but also when a maximum value of the vibration acceleration in the frequency domain exceeds a predetermined threshold. Therefore, variation in the rotation speed of the rotary shaft and the chatter vibration occurrence state can be stored in association with each other. Hence, an operator can learn the rotation speed of the rotary shaft and the chatter vibration occurrence state in association with each other. As a result, chatter vibration can be suppressed easily and effectively.
    Type: Grant
    Filed: September 26, 2011
    Date of Patent: October 14, 2014
    Assignee: Okuma Corporation
    Inventors: Tomoharu Ando, Hiroshi Ueno
  • Patent number: 8836195
    Abstract: A motor is provided. When m is half of a number of slots of one phase and n is a divisor of m, the overall parallel winding of a total number of parallels p is equally divided n-fold into partial parallel windings Ni, having a number of parallels p/n, each partial parallel winding Ni comprises m sub-coils, the m sub-coils including n types of m/n sub-coils having a number of turns tj, at least one of the sub-coils differing in number of turns from the other sub-coils, and, for each pair of the slots in the stator, one sub-coil of each partial parallel winding Ni is wound around the pair of slots, and n sub-coils wound around the pair of the slots include every one of the n types of the sub-coils of the numbers of tj.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: September 16, 2014
    Assignee: Okuma Corporation
    Inventor: Takanori Yokochi
  • Patent number: 8823367
    Abstract: In a rotation angle detection apparatus, a signal detected by a magnetoresistive element is digitalized before being subjected to subtraction of the optimum correction parameter therefrom in a subtractor, the optimum correction parameter being stored in advance in a memory. Note that during the initial transmission at the time of activation, the data size ā€œnā€ of a detection target obtained by a CPU from a control device is transferred to the memory, so that the optimum correction parameter for the data size of the detection target is selected. With the above, the detection unit can relatively readily cope with a request for enlargement or the like of a through hole size made by a machine side, and detection accuracy is not deteriorated and an error in absolute position processing is reduced when the curvature of the detection target is changed.
    Type: Grant
    Filed: June 22, 2011
    Date of Patent: September 2, 2014
    Assignee: Okuma Corporation
    Inventor: Noriyuki Fukui
  • Patent number: 8801345
    Abstract: A tool main spindle, whose cutting angle can be changed, is translated by an X-axis moving mechanism portion on an X-axis provided in a plane perpendicular to an axis of a work; and is translated on a Y-axis by a Y-axis moving mechanism portion. Cutting of the work is performed by setting the cutting angle of the tool main spindle to an angle of the cutting tool at which the work has large dynamic rigidity, and causing an axis of a cutting tool to cross the work axis, and cutting the work with the cutting tool toward the axis of the work by cooperatively operating the X-axis moving mechanism portion and the Y-axis moving mechanism portion.
    Type: Grant
    Filed: June 11, 2009
    Date of Patent: August 12, 2014
    Assignee: Okuma Corporation
    Inventor: Kiyoshi Yoshino
  • Patent number: 8800159
    Abstract: When calculating a compensation value for a geometric error, a first index representing an order of connection of drive axes in a machine and a second index representing an order of connection of the drive axes including the geometric error are obtained. Then, a first vector is obtained by performing a matrix operation of a reference vector according to information on the connection in the first index, and a second vector is obtained by performing the matrix operation of the reference vector according to information on the connection in the second index. Thereafter, a difference between the first vector and the second vector is obtained as the compensation value.
    Type: Grant
    Filed: April 13, 2012
    Date of Patent: August 12, 2014
    Assignee: Okuma Corporation
    Inventor: Tetsuya Matsushita
  • Publication number: 20140217952
    Abstract: A position control apparatus is configured to perform full-closed control for controlling the position of a driven member. The position control apparatus includes a vibration period and amplitude detector that detects a vibration period and a vibration amplitude included in a difference value between the position command value and the driven member position detection value. The position control apparatus also includes a constant vibration detector that outputs, as a vibration period of the constant vibration, a vibration period obtained while the driven member is not in an acceleration/deceleration state and the vibration period and the vibration amplitude detected by the vibration period and amplitude detector are equal to or greater than a vibration period threshold value and a vibration amplitude threshold value, respectively. The position control apparatus also includes a control parameter changer that changes the control parameter based on the vibration period output from the constant vibration detector.
    Type: Application
    Filed: February 7, 2014
    Publication date: August 7, 2014
    Applicant: OKUMA Corporation
    Inventor: Masashi Miyaji
  • Publication number: 20140216218
    Abstract: A tool-main-spindle, whose cutting angle can be changed, is translated by an X-axis moving mechanism portion on an X-axis provided in a plane perpendicular to an axis of a work, and is translated on a Y-axis by a Y-axis moving mechanism portion. Cutting of the work is performed by setting the cutting angle of the tool-main-spindle to an angle of the cutting tool at which the work has large dynamic rigidity, and causing an axis of a cutting tool to cross the work axis, and cutting the work with the cutting tool toward the axis of the work by cooperatively operating the X-axis moving mechanism portion and the Y-axis moving mechanism portion.
    Type: Application
    Filed: April 9, 2014
    Publication date: August 7, 2014
    Applicant: Okuma Corporation
    Inventor: Kiyoshi YOSHINO
  • Publication number: 20140210297
    Abstract: A plurality of coils C1 to Cm that constitutes a whole winding L of each phase is divided into g coil groups G1 to Gg for each phase. Each coil group is, for example, constituted by coils C1 to C4 wound around four polar teeth continuously disposed. The number of turns of respective end coils C1 to C4 of the coil group is less than the number of turns of central coils C2 and C3. Further, the whole winding L includes n partial windings N1 to Nn, in which a coil Cj (j is an integer in the range from 1 to m) is constituted by n sub coils S(1,j) to S(n,j) that are formed by the n partial windings. It is feasible to set a non-integer value as an effective number of turns of a coil when the number of turns of each sub coil is appropriately selected.
    Type: Application
    Filed: January 29, 2014
    Publication date: July 31, 2014
    Applicant: OKUMA Corporation
    Inventor: Tatsuya Shizu
  • Patent number: 8790054
    Abstract: A spindle attachment includes a device body having an attachment surface detachably attached to an end face of a spindle head. Fixed and movable teeth move the body in a direction of an axial line of the spindle to engage the spindle head and the body so as to freely restrict or release rotation of the body with respect to the spindle head. A coil spring urges the body so that the attachment surface is pressed onto the end face of the spindle head with the fixed and movable teeth ready for engagement. A pressure cylinder causes fluid pressure to act on the attachment surface against the spring force to release engagement between the fixed and movable teeth. A key and a key groove transmit rotation of the spindle to the body with the fluid pressure of the cylinder acting on the attachment surface of the device body.
    Type: Grant
    Filed: August 4, 2010
    Date of Patent: July 29, 2014
    Assignee: Okuma Corporation
    Inventor: Wataru Hongou
  • Publication number: 20140126845
    Abstract: A main spindle device of a machine tool includes a plurality of bearings that rotatably support a main spindle of the machine tool, and that are placed inside a housing with a pressure receiving member interposed between the bearings and the housing. The pressure receiving member is capable of moving in a direction perpendicular to an axial direction of the main spindle. A pressure chamber, which a pressure medium pressing the pressure receiving member toward the bearings in the perpendicular direction is supplied to, is formed in the housing. A plurality of the pressure chambers are independently formed in the housing so as to correspond to the bearings, respectively. The main spindle device further includes a plurality of adjustment units provided independently so as to correspond the pressure chambers, respectively, and each capable of independently adjusting a pressure of the pressure medium for a corresponding one of the pressure chambers.
    Type: Application
    Filed: October 23, 2013
    Publication date: May 8, 2014
    Applicant: Okuma Corporation
    Inventor: Issei KOIKE
  • Publication number: 20140121817
    Abstract: A machine tool includes a number-of-same-rotation-speed-cutting-passes computing section that decides the number of same rotation speed cutting passes. The number-of-same-rotation-speed-cutting-passes computing section determines the cutting mode of a threading process based on a set machining program etc., and automatically decides an optimal number of same rotation speed cutting passes according to the cutting mode. Thus, even unskilled operators can easily suppress chatter vibrations, and can easily use the machine tool.
    Type: Application
    Filed: October 11, 2013
    Publication date: May 1, 2014
    Applicants: National University Corp. Nagoya University, OKUMA CORPORATION
    Inventors: Kohei NISHIMURA, Kiyoshi YOSHINO, Shigeki UENO, Eiji SHAMOTO
  • Publication number: 20140121816
    Abstract: A machine tool includes a first-pass rotation speed computing section. The first-pass rotation speed computing section automatically decides whether the main spindle rotation speed in the first pass should be a high rotation speed or a low rotation speed so that cutting in the last tool pass is performed at the high rotation speed. Thus, cutting of the last tool pass at the low rotation speed can be reliably prevented.
    Type: Application
    Filed: October 11, 2013
    Publication date: May 1, 2014
    Applicant: Okuma Corporation
    Inventor: Kohei NISHIMURA
  • Publication number: 20140114462
    Abstract: A chatter vibration suppressing method includes acquiring a moment of inertia of a rotating body, recording a value indicating the acquired moment of inertia into a machining program, and calculating a variable amplitude and a variable period when a rotation speed of the rotating body is varied in order to suppress chatter vibration from the value indicating the moment of inertia recorded in the machining program and the maximum input power of a motor for rotating the rotating body.
    Type: Application
    Filed: October 18, 2013
    Publication date: April 24, 2014
    Applicant: OKUMA Corporation
    Inventors: Kiyoshi Yoshino, Yuto Mizukami, Takayuki Kato, Noriyoshi Ito, Nobuki Nishidera