| Okuma Corporation Patent applications |
| Patent application number | Title | Published |
|---|
| 20120133311 | MOTOR MAGNETIC POLE POSITION CORRECTION METHOD - A motor magnetic pole position correction method includes preventing a movement of a movable element of a direct drive motor by mechanical brake (step S | 05-31-2012 |
| 20120109360 | MACHINE TOOL - In a machine tool which includes a rotary shaft configured to allow a tool or a workpiece to be attached thereto, a driving unit for causing the rotary shaft to rotate is regulated to change a rotation speed of the rotary shaft in such a manner that the rotation speed oscillates with a given amplitude and a given period with respect to a given mean rotation speed, so that chatter vibrations can be suppressed. A parameter display control unit configured to cause a display device to display parameter information related to predetermined parameters for changing at least one of the mean rotation speed, the amplitude and the period is provided so that the parameters can be changed based upon the parameter information displayed in the display device. | 05-03-2012 |
| 20120101624 | METHOD AND APPARATUS FOR SUPPRESSING VIBRATION - A vibration suppressing method and a vibration suppressing device are disclosed. After detection of chatter vibration using at least one vibration detecting device, a stable rotation speed for suppressing the chatter vibration is calculated using a stable rotation speed calculating device. A determination device then compares a detection value detected by the vibration detecting device, a predetermined setting value, and/or a current value that is calculated based on at least one of the detection value and the setting value, to a predetermined determination reference value that is previously set. Thereafter, the determination device determines whether or not the stable rotation speed is adopted in accordance with the comparison result, and changes rotation speed of the rotary shaft to the stable rotation speed if the stable rotation speed is adopted. | 04-26-2012 |
| 20120097411 | METHOD FOR MONITORING ROTARY SHAFT ROTATION SPEED FLUCTUATION IN MACHINE TOOL, MONITOR APPARATUS, AND MACHINE TOOL - In suppressing chatter vibration of a rotary shaft in a machine tool by fluctuating rotation speed of the rotary shaft, easy setting of a fluctuation parameter is realized. In a monitor apparatus of the machine tool, a graph showing a fluctuation amplitude of the rotation speed is displayed. On this graph, a current fluctuation position (first point) is indicated by a black circle marker, and also, a power limit line L of a motor fluctuation period is depicted based on a predetermined equation. In an area not exceeding the power limit line L, a new fluctuation position (second point) having a larger fluctuation amplitude and a shorter fluctuation period than the current fluctuation position is calculated and indicated with an arrow A guiding this new point from the current fluctuation position. | 04-26-2012 |
| 20120095724 | OPERATING HISTORY MANAGEMENT METHOD AND OPERATING HISTORY MANAGEMENT APPARATUS - 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. | 04-19-2012 |
| 20120093603 | VIBRATION SUPPRESSING METHOD AND VIBRATION SUPPRESSING DEVICE FOR USE IN MACHINE TOOL - In a machine tool having a rotary shaft for use in rotating a tool or a workpiece, a plurality of stable rotation speeds at which the chatter vibrations are expected to be suppressed, and at least one switching rotation speed across which a dynamic characteristic of a rotary shaft system changes are stored. The plurality of stable rotation speeds may be determined from chatter vibrations detected using a vibration detection unit. Optimum rotation speed that is a rotation speed to which a rotation speed of the rotary shaft is changeable without crossing the switching rotation speed is selected from the plurality of stable rotation speeds, and the rotation speed of the rotary shaft is changed to the optimum rotation speed. Thus, chatter vibrations generated during rotation of the rotary shaft can be suppressed effectively. | 04-19-2012 |
| 20120093598 | MONITORING METHOD AND MONITORING APPARATUS FOR MACHINE TOOL, AND MACHINE TOOL - The monitoring apparatus includes vibration sensors that detect vibration accompanying machining, a rotation detector and a rotation detection section that detect rotation of a main spindle, and a stability limit and vibration distribution calculation section that creates, on the basis of vibration information obtained from the vibration sensors and a rotation speed of the main spindle detected by the rotation detector and rotation detection section, both a stability limit diagram illustrating a relationship between the rotation speed and a stability limit of the machining and a vibration distribution diagram illustrating a relationship between the rotation speed and the vibration, and displays the created diagrams on a monitor in a vertical arrangement. | 04-19-2012 |
| 20120065766 | VIBRATION SUPPRESSING DEVICE - A vibration suppressing device includes a memory unit storing a stable rotation speed calculated by an arithmetical unit in association with a rotation speed range that includes the stable rotation speed, in which, when a command rotation speed that is a rotation speed of a rotary shaft is inputted in starting machining operation by rotation of the rotary shaft and, the arithmetical unit determines whether the command rotation speed is included in the rotation speed range or not, reads out the stable rotation speed when the command rotation speed is included in the rotation speed range and outputs the stable rotation speed to an NC device instead of the command rotation speed, and starts the machining operation at the stable rotation speed. | 03-15-2012 |
| 20110316530 | ROTATION ANGLE DETECTION APPARATUS - 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 “n” 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. | 12-29-2011 |
| 20110281658 | ROTARY SHAFT DEVICE - In a rotary joint for a rotary shaft device, ring-shaped inner seals and outer seals are projectingly arranged, and concentric with faces of a front joint disk and a rear joint disk opposing with each other respectively. A ring-shaped inner space communicates with forward communication holes, and a ring-shaped outer space communicates with backward communication holes. The inner and outer space are adjacently arranged concentrically between the inner seals and the outer seals. The forward communication holes and the backward communication holes in the reciprocating flow passages and the front joint disk are arranged at an equal distance in the peripheral direction of the opposing faces. | 11-17-2011 |
| 20110280679 | COOLING STRUCTURE FOR MACHINE TOOL MAIN SPINDLE - A coolant supply section that supplies coolant to a main spindle and a coolant recovery section that recovers the coolant from the main spindle are formed in a housing. A coolant flow path that allows the coolant to flow from the coolant supply section to the coolant recovery section is formed in the main spindle. The coolant flow path in the main spindle includes a coolant receiving portion that receives the coolant supplied from the coolant supply section, and a plurality of hole-shaped flow paths formed to extend in the axial direction of the main spindle from the coolant receiving portion. The coolant receiving portion includes an annular groove that is recessed in the outer circumference of the main spindle. The hole-shaped flow paths are formed to extend generally straight toward the coolant recovery section and with an inclination to the radially outer side of the main spindle. | 11-17-2011 |
| 20110218666 | METHOD OF CONTROLLING THREAD CUTTING - The present invention provides a simple method of reducing an incomplete thread portion comprising the steps of: (a) transferring a tool in the direction of the X-axis to position the tool at the point where thread cutting is to be started; (b) transferring the tool in the direction of the Z-axis in synchronization with the rotation of the main spindle to cut threads in work; (c) performing a pullout operation by deceleration in the direction of the Z-axis and acceleration in the direction of the X-axis during a predetermined acceleration/deceleration time Ta so as to retract the tool in the direction of the X-axis; and (d) withdrawing the tool in the direction of the Z-axis to return the tool to the reference point of the thread cutting cycle. In the step (c) of the pullout operation, a command is issued concurrently with the start of the acceleration/deceleration time so as to realize a pullout speed Ve in the direction of the X-axis that exceeds an allowable maximum speed Vmax to increase the acceleration in the direction of the X-axis. The speed command directing the tool to move in the direction of the X-axis is maintained at the value of zero from the elapse of command time Te until the acceleration/deceleration time Ta expires so as to maintain the actual speed of the tool in the direction of the X-axis at or below the allowable maximum speed Vmax. | 09-08-2011 |
| 20110188958 | CUTTING METHOD - There is provided a cutting method for cutting a work by rotating a rotary tool with a circular cutting edge around an axis while a cutting fluid is supplied thereto. Cutting is performed by means of the rotary tool which is rotated in the same rotational direction as an outflow direction of chips, and the rotary tool is rotated at a rotational speed of the rotary tool at which a circumferential speed of the cutting edge is higher than an outflow speed of the chips. Thus, the area of direct solid contact between the rotary tool and the chips is reduced with the aid of a dynamic pressure effect, and the abrasion of the rotary tool is suppressed. | 08-04-2011 |
| 20110163221 | METHOD FOR CONTROLLING DEFLECTION IN STRUCTURAL MEMBER - A method for controlling deflection caused in a structural member when a force is applied to the structural member is described. The method includes a step of generating rotation torque in the structural member in such a direction as to cancel out the force applied to the structural member. The rotation torque is generated by a motor and a load inertia applying device such as a disc connected to the rotor. A stator of the motor is connected to the structural member and the load inertia applying device applies load inertia to a rotor of the motor. | 07-07-2011 |
| 20110156699 | MULTI-TURN ANGLE SENSOR - A multi-turn angle sensor includes rotors | 06-30-2011 |
| 20110135415 | VIBRATION SUPPRESSING DEVICE - In a vibration suppressing device provided in a machine tool having a rotary shaft for use in rotating a tool or a workpiece, for suppressing chatter vibrations generated during rotation of the rotary shaft, an arithmetical unit performs an analysis on a vibration of the rotary shaft detected by a detector (vibrations sensors) whenever the vibration is detected and a computation based on a result of the analysis. An operator, while checking results of the analysis and/or the computation displayed in real time in a display unit, manipulates a manipulation element to enter a command to change a rotation speed of the rotary shaft into a rotation speed control unit (NC unit) which controls the rotation speed according to the command entered by the operator through the manipulation element. | 06-09-2011 |
| 20110079121 | MACHINE TOOL AND BORING METHOD - In a machine tool ( | 04-07-2011 |
| 20110056343 | MACHINE TOOL - In a machine tool, a support member to which a headstock is mounted movably in an upward-downward direction is movable so as to change a position thereof in a horizontal direction relative to that of a bed. A guide member is provided on the bed and configured to guide the support member. An engageable portion at which the support member is supported by the guide member is located in the support member at a level within a range of upward-downward movement of the headstock along the support member. | 03-10-2011 |
| 20110040523 | METHOD AND PROGRAM FOR IDENTIFYING ERRORS - A method for identifying geometric errors with respect to at least two translational axes and at least one rotational axis of a machine using a control device is disclosed. The method comprises the steps of: measuring positions of a jig in three-dimensional space using a position measurement sensor, wherein a measurement is carried out when the jig being indexed around the rotational axis by a plurality of angles is located at the positions; approximating a plurality of measured values of the positions measured in the measuring step to a circular arc; and calculating an error in regard to a center position of the rotational axis and/or a tilt error in the rotational axis, and tilt errors in the translational axes, based on the circular arc resulting from the approximating step. | 02-17-2011 |
| 20110015050 | TOOL MAGAZINE - A tool magazine includes: a rotary shaft; and a plurality of tool gripping members radially extending around the rotary shaft. The tool magazine is configured to transfer tools between the tool gripping members and a tool attachment portion of a machine tool. The plurality of tool gripping members are arranged such that two tool gripping members are at least partially adjacent to each other and disposed in different heights in a direction of the rotary shaft, so that a tool is transferred between one of the two tool gripping members and the tool attachment portion without interference of the tool attachment portion against a tool gripped by the other one of the adjacent tool gripping member. | 01-20-2011 |
| 20100225180 | LINEAR MOTOR - There had been a problem that the installation area of a linear motor becomes large when a plurality of linear motors are arranged in parallel in the travel direction of a mover. | 09-09-2010 |
| 20100109594 | POSITION CONTROL APPARATUS FOR NUMERICALLY CONTROLLED MACHINE - In a position control apparatus that drives a feed-axis with a servomotor of a machine tool, the machine tool maybe quickly accelerated or decelerated in a state where a machine structural member that supports and fixes a structural member including a driving system has a lower rigidity, or in a state where an element having a lower rigidity is present beyond a load position where the detection by a linear scale is performed. In such cases, a generated deflection may induce a displacement in a mechanical system. A relative locus error may be generated between a workpiece to be processed and a front end portion of the tool. Further, a mechanism rigidity generally changes according to a machine posture. The generated deflection amount changes in magnitude. The present embodiment estimates and compensates a displacement amount of the front end portion of the tool that may be caused by the deflection of the mechanical system. Moreover, in calculating an estimation amount, the present embodiment can change a parameter corresponding to the mechanism rigidity based on the machine posture. Thus, the front end of the tool can move accurately along a desired locus relative to the workpiece to be processed. | 05-06-2010 |
| 20100104388 | VIBRATION SUPPRESSING METHOD AND VIBRATION SUPPRESSING DEVICE FOR MACHINE TOOL - A vibration suppressing method and a vibration suppressing device are disclosed. After a tool is attached to a main spindle, a modal parameter of the tool or a workpiece is computed. Thereafter, a relation between chatter frequency and phase difference is calculated as an approximation formula based on the obtained modal parameter and machining conditions. If chatter vibration occurs after initiation of the machining, a chatter frequency corresponding to a target phase difference is obtained using the approximation formula, and based on the obtained chatter frequency, the number of tool flutes and the main spindle rotation speed, the optimum rotation speed is calculated. The rotation speed of the main spindle is then changed in accordance with the obtained optimum rotation speed. | 04-29-2010 |
| 20100101383 | COMBINATION MACHINING LATHE - In a combination machining lathe, a workpiece holding device holds a workpiece in a manner that permits the workpiece to rotate around an axis parallel to a direction of a horizontal Z axis. A tool post holds a tool that comprises a holder and a bit. The tool held by the tool post is indexed to a position in which the longitudinal axis of the holder is parallel to an X axis direction. The bit of the tool held by the tool post is angled such that a longitudinal axis of the bit is disposed in a position tilted away from the X axis direction closer to a horizontal axis in a plane containing the X axis and the Y axis. A turning operation is performed while the tool and/or the workpiece are moved relative to each other in a direction of the longitudinal axis of the bit. | 04-29-2010 |
| 20100087948 | COLLISION PREVENTING DEVICE INCORPORATED IN NUMERICAL CONTROL APPARATUS - A collision preventing device includes an acceleration/deceleration simulating unit | 04-08-2010 |
| 20100039059 | MOTOR CONTROLLER - A motor controller is provided which has a function to prevent the falling of a shaft when the power supply to a motor is turned on. | 02-18-2010 |
| 20100010662 | VIBRATION SUPPRESSING METHOD AND DEVICE - A stable rotation speed is acquired by finely changing a rotation speed of a rotary shaft | 01-14-2010 |
| 20100005936 | CUTTING METHOD AND CUTTING APPARATUS - 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. | 01-14-2010 |
| 20090302796 | POSITION CONTROL APPARATUS - A position control apparatus includes a reverse displacement calculation unit configured to calculate a reverse displacement that represents an amount of movement made from a preceding reverse point to a current reverse point by an axis that performs a reversing motion; a reversing-time segmenting number calculation unit configured to compare the reverse displacement to a predetermined value, and, when the reverse displacement is less than the predetermined value, increase a value of a reversing-time segmenting number, which is a coefficient indicating a number of segments per unit time during a reversing motion, and, when the reverse displacement is greater than or equal to the predetermined value, decrease the value of the reversing-time segmenting number; and a quadrant inversion compensation unit configured to automatically adjust a quadrant inversion compensation amount according to the reversing-time segmenting number and perform the quadrant inversion compensation based on the automatically adjusted compensation amount. | 12-10-2009 |
| 20090240482 | MACHINING SIMULATION APPARATUS - A machining simulation apparatus ( | 09-24-2009 |
| 20090218893 | LINEAR MOTOR MOUNTING STRUCTURE - The present invention provides a magnetic attractive force-offsetting linear motor which prevents motor thrust from varying due to changes in the position on a stator, thus enabling improvement of the motor thrust and of the accuracy of the machine tool and the quality of a processed surface. A magnetic attractive force offsetting linear motor has a base | 09-03-2009 |
| 20090209398 | MACHINE TOOL - A machine tool includes a headstock provided with a main spindle and movable in a direction different from a direction of axis of the main spindle, a tool post mounted on the headstock so as to be movable in the direction of axis of the main spindle, and a tool change unit configured to change a tool attached to the main spindle with another tool after an extremity of the main spindle has been moved to a predetermined tool change position. In this machine tool, when an extremity of the tool post is positioned in the tool change position by the movement of the headstock and also by the movement of the tool post, the tool change unit performs change of a tool attached to the tool post with another tool by the same tool change operation as that for the main spindle. | 08-20-2009 |
| 20090199685 | TAILSTOCK CONTROL DEVICE - A tailstock control device supports an object to be machined by driving and controlling a servo motor which drives a driving system of a tailstock having a spring member in forward and backward directions, to cause a tailstock center connected to the tailstock to contact a center hole of the object to be machined. The tailstock control device comprises a limit torque value calculating unit which calculates, as a limit torque value (Tm), a drive torque value of the servo motor necessary for supporting the object to be machined, and a servo control unit which drives and controls the servo motor to attempt to move the tailstock at a tailstock movement velocity (Vs) which is set in advance, until an output torque value (Tr) of the servo motor reaches the limit torque value (Tm). The limit torque value (Tm) is calculated by subtracting, from the support thrust (Fa) necessary for supporting the object to be machined, an excessive thrust Fs which is calculated based on the tailstock movement velocity (Vs). | 08-13-2009 |
| 20090171594 | MACHINE DIAGNOSING METHOD AND DEVICE THEREFOR - A machine diagnosing device | 07-02-2009 |
| 20090112376 | POSITION CONTROLLING DEVICE - A structure is provided in which a thrust feed forward structure for operating a structure to be driven without vibration and a control structure which simultaneously compensates for positional deviation caused by the thrust feed forward structure and positional deviation caused by a base displacement are included in a position controlling device ( | 04-30-2009 |
| 20090112356 | NUMERICAL CONTROL APPARATUS WITH MANUAL SHIFT OPERATION FUNCTIONALITY - A numerical control apparatus provides for manual shift operation involving feed shafts of a machine tool in terms of a work coordinate system easily and readily understood by an operator. The numerical control apparatus includes a manual shift amount input unit for receiving an amount of manual shift involving linear feed shafts as operator-input data in terms of a work coordinate system defined on the work revolved or rotated by a rotary feed shaft. The numerical control apparatus further includes a manual shift amount cumulative storage for cumulatively storing the received amount of manual shift in terms of a work coordinate system. Also included is a cumulative shift amount coordinate converter for converting the cumulative amount of shift from the work coordinate system data to data in terms of machine coordinate system defined on the machine tool. The apparatus's manual shift amount superimposing unit then superimposes the converted cumulative amount of shift on a controlled variable commanded in a machining program to generate the result to servo drivers. | 04-30-2009 |
| 20090110499 | METHOD FOR SUPPRESSING VIBRATION AND DEVICE THEREFOR - The vibration suppressing device includes vibration sensors, a FFT calculating unit, a store device, a calculating unit, and a NC device. The vibration sensors detect a time-domain vibrational acceleration of a rotary shaft during rotating. The FFT calculating unit calculates a frequency of chatter vibration and a frequency-domain vibrational acceleration in the frequency of chatter vibration on the basis of the detected time-domain vibrational acceleration. The store device stores the frequency-domain vibrational acceleration, the frequency of chatter vibration and the like as machining information. When the calculated maximum frequency-domain acceleration exceeds a predetermined threshold value, the calculating unit stores the maximum acceleration, the frequency of chatter vibration, and the like as current machining information in the store device, and calculates an optimal rotation speed of the rotary shaft, by which the chatter vibration can be suppressed, based on the current machining information and previous machining information stored in the store device. The NC device rotates the rotary shaft at the optimal rotation speed. | 04-30-2009 |
| 20090082900 | NUMERICAL CONTROLLER OF MACHINE TOOL - A numerical controller having a function-generating unit which executes function generation for shaft movement according to a machining program is provided, the numerical controller further comprising a unit which stores shape data of the movable unit and shape data of an interfering structure; a retracting direction determining unit which determines a retracting direction; an interference checking position calculating unit which successively calculates, as an interference checking position, a position in which a desired distance is added to the current position of the movable unit according to the determined retracting direction; an interference confirming unit which confirms presence or absence of interference between the shape data of the movable unit and the shape data of the interfering structure by virtually moving the shape data of the movable unit; and a power outage detecting unit which sends a power outage signal to a DC power supply unit and the function-generating unit during power outage, wherein the function-generating unit executes function generation according to a result of the interference confirming unit. | 03-26-2009 |
| 20090069927 | VIBRATION SUPPRESSING DEVICE FOR MACHINE TOOL - A calculating member carries out Fourier analysis of a vibrational acceleration to calculate a maximum acceleration and frequency thereof. The calculating member then compares the maximum acceleration with a threshold value, and when the acceleration exceeds the threshold value, the calculating member calculates a k-value and phase information, and stores each calculated value. When retrying is selected, the calculating member determines a type of a current chatter vibration from the phase information, determines the existence of a chatter vibration which is different from the determined chatter vibration, and calculates each new phase information according to the determined chatter vibration and an existence of a different chatter vibration which had been generated before generation of the current vibration. The calculating member then calculates a k1-value from new phase information, calculates the optimum rotation speed by using the k1-value, and changes the rotation speed to the optimum rotation speed. | 03-12-2009 |
| 20090026997 | CONTROL APPARATUS FOR RELUCTANCE TYPE SYNCHRONOUS MOTOR - A control apparatus for a motor (in | 01-29-2009 |
| 20090000907 | PALLET EXCHANGER - A pallet exchanger capable of providing a sufficient operation space on an operator's access side, for example, in front of a machining space, without increasing the size of the exchanger is provided. | 01-01-2009 |
| 20090000441 | CUTTING METHOD - An object is to provide a cutting method capable of efficiently removing cutting chips around a cutting point with a little electric power, and cutting a work with high accuracy. | 01-01-2009 |
| 20080289923 | VIBRATION SUPPRESSING DEVICE AND VIBRATION SUPPRESSING METHOD FOR MACHINE TOOL - A vibration suppressing device and a vibration suppressing method that are capable of obtaining an accurate optimum rotation speed and shortening a time period from generation of chatter vibration to calculation of the optimum rotation speed are provided. The vibration suppressing device | 11-27-2008 |
| 20080267749 | PALLET TRANSFER SYSTEM - A pallet transfer system capable of smoothly transferring a pallet between a machine tool and a pallet conveying device is provided. | 10-30-2008 |
| 20080249653 | NUMERICAL CONTROL UNIT - A numerical control apparatus with a single block function is provided including a start button ( | 10-09-2008 |
| 20080231266 | ABSOLUTE ENCODER - A printed circuit board on which are laid out detection windings and an excitation magnetic flux detection winding formed of conductor patterns is disposed so as to be spaced a predetermined gap quantity from a binary cyclic random number sequence code plate which is rotatably disposed. A U-shaped exciting core on which an excitation winding is wound is disposed on the back surface side of the printed circuit board. The detection windings detect and output, as voltage values, reluctance changes as which excitation magnetic fluxes generated from the excitation winding fluctuate between this excitation winding and the concave/convex portion of the binary cyclic random number sequence code plate. Reduction of precision due to interferences between the excitation magnetic fluxes for detecting an absolute code and other excitation magnetic flux is thereby prevented. | 09-25-2008 |
| 20080231265 | POSITION DETECTOR WITH TILT SENSOR - A scale section is made of a magnetic material. A repeated pattern is recorded at a uniform pitch on the surface of the scale section. A sensor section is provided independently from the scale section. The sensor section is provided with a magnetic position sensor that reads the pattern, on a surface close to the surface of the scale section. Further, the sensor section is provided with a magnetic tilt sensor that detects a tilt between the surface of the scale section and the surface of the sensor section on which the position sensor is located. The magnetic position detector in which the scale section and the sensor section are separated from each other can be efficiently fixed to a detection target using the tilt sensor. | 09-25-2008 |
| 20080228423 | POSITION DETECTOR - Two position sensors provide, as outputs, two signals that vary sinusoidally at a pitch of wavelength λ with respect to a displacement of a target and have phases shifted from each other by 90°. A memory unit has stored therein offset values for the two signals, and two subtractors eliminate the offset values from the two signals, respectively. The two signals after offset elimination are converted into position data in an interpolation calculator. A radius calculator calculates a radius value of the two signals after offset elimination. An FFT calculates offset values based on the position data and the radius values, and the calculated offset values are used to update the values stored in the memory unit. An amplitude ratio correction value and a phase difference correction value for the two signals are updated similarly. By performing elimination of the components that degrade interpolation accuracy at every rotational position, interpolation accuracy is improved. | 09-18-2008 |
| 20080224693 | ABNORMALITY DETECTION APPARATUS FOR ROTARY TYPE ABSOLUTE ENCODER - In order to cope with many rotor diameters using a single type of stator portion, two stator portions, each having a built-in signal processing circuit for detecting absolute positions independently, are disposed in opposition at positions which differ from each other with respect to a rotational center of a rotor portion. When one of the stator portions receives a request command RX from an external device, it transmits a detected serial communication signal. The other stator portion receives the transmitted serial communication signal, determines a position detection abnormality, and notifies the abnormality to the external device when a difference between the received absolute position and the absolute position detected by the other stator portion exceeds a deviation previously set for 180 degrees. | 09-18-2008 |
| 20080222834 | WIPER | 09-18-2008 |
| 20080215178 | METHOD FOR ESTIMATING THERMAL DISPLACEMENT IN MACHINE TOOL - After a thermal displacement correcting program has started, a temperature is measured with a temperature sensor in S | 09-04-2008 |
| 20080203959 | SERVO MOTOR CONTROLLER - A controller includes a rotating direction detecting unit | 08-28-2008 |
| 20080202297 | TURRET TOOL REST AND MACHINE TOOL - A turret tool rest | 08-28-2008 |
