Abstract: A synchronous motor 100 includes a rotor 20 having a permanent magnet 26 on the surface of or inside the rotor, a stator 10 made of a soft magnetic material and having tooth members T1 to T18 and slots S1 to S18, and element coils 11, 12 wound around each of the tooth members T1 to T18 as concentrated windings and arranged in multiple layers along the extending direction of the tooth members T1 to T18. The element coils 11, 12 are provided three coils each for each phase in a circumferential direction to form rotating direction windings 101 to 206 for each phase. For each phase, the rotating direction windings 101 to 206 are displaced from each other by one slot in the rotating direction between adjacent layers. As a result, torque ripples are reduced in motors using concentrated windings.

Abstract: In an absolute position detector, a relative error calculation circuit calculates, at times indicated by a clock signal C1, a relative error E between an output ?2 from an absolute position detection sensor and a position output ?1 from a high-resolution position detection sensor. An abnormality judgment unit judges whether the relative error E exceeds a preset abnormality judgment value. A clock switching unit outputs, as the clock signal, a high-speed clock CH having a period shorter than a noise generation period when the relative error E is judged as exceeding the preset abnormality judgment value, and outputs a slow-speed clock CL in other cases. A counter measures, based on the clock signal C1, a duration in which the abnormality detection signal AF is maintained HI, and outputs an alarm when the duration exceeds the noise generation period.

Abstract: Determination of chatter vibration is done for a plurality of peak values that appears when frequency-domain vibrational acceleration is obtained through fast Fourier analysis on time-domain vibrational acceleration. In machining at a low rotation speed and machining using a tool with small flute number in particular, a type of chatter vibration that has occurred can be accurately determined, and “natural vibration type forced chatter vibration” occurring due to friction between a tool and a workpiece and an impact force caused by machining can also be determined.

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.

Abstract: Coils are formed into a coil group for a single phase by serially connecting a plurality of coils so that the resulting magnetic flux distribution is a sine wave distribution. The coil group for a single phase is constituted by a plurality of coil sets, formed from two coils that are wound around two adjacent magnetic pole teeth, connected in series. Each coil set includes coils of the two magnetic pole teeth constituting that coil set wound in opposite directions to each other looking from the inside of the stator. An electrical wire extending from an end winding of each coil is turned back so as to run in a direction opposite to an electrical wire connection to a start winding of that coil, and is connected to either a start winding of the next coil or a connection terminal.

Abstract: The amount of lubricant oil supplied to a bearing is optimized. A main-shaft lubrication device includes a supply device for variably supplying lubricant oil to bearings which support a main shaft, a collection device for collecting, from the bearings, the lubricant oil supplied from the supply device, a measurement device for measuring the amount of lubricant oil collected by the collection device, and a control device for controlling the amount of lubricant oil to be supplied from the supply device.

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.

Abstract: When generation of a chatter vibration is detected, a parameter calculation device calculates a first frequency range and a second frequency range. A determination validity is calculated in consideration of a rotation speed detection resolution and a frequency resolution, and based on a ratio of a frequency range of rotational-period forced chatter vibration to a frequency range of regenerative chatter vibration. It is determined based on the determination validity whether the generated chatter vibration is regenerative chatter vibration, rotational-period forced chatter vibration, or flute-passage-period forced chatter vibration.

Abstract: The present invention provides a method of computing a correction value for the machine tool having two or more translational axes and one or more rotational axes for correcting error in a position and an orientation of the tool with respect to a workpiece due to the geometric error. The method includes a rotational axis correction value computing step (S3) for computing a correction value for the rotational axis by use of a geometric parameter representing the geometric error, and a translational axis correction value computing step (S4) for computing a correction value for the translational axis by use of a command value for each of the rotational axes, a command value for each of the translational axes, and the geometric parameter.

Abstract: The present invention provides a method and the like that are capable of calculating a correction value for a rotational axis and make it possible to correct an error in position or position and posture of a tool, which results from a geometric error, correct an error in posture of the tool, and also enhance the accuracy in machining by preventing a translational axis from operating in an infinitesimal manner due to a correction command. In a machine tool having two or more translational axes and one or more rotational axes, a correction value for each of the translational axes is calculated using a command position of each of the rotational axes, a coordinate value of a correction reference point as one point designated in advance in a command position space of each of the translational axes, and a geometric parameter representing the geometrical error.

Abstract: 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 includes: vibration sensors for detecting time-domain vibrational accelerations of a rotary shaft in rotation; and a control device for calculating a chatter frequency and a frequency-domain vibrational acceleration of the rotary shaft at the chatter frequency on the basis of the time-domain vibrational accelerations detected by the vibration sensors, and when the calculated frequency-domain vibrational acceleration exceeds a predetermined threshold value, calculating an optimum rotation speed on the basis of a predetermined parameter, and rotating the rotary shaft at the calculated optimum rotation speed.

Abstract: A spiral groove flow passage with a clockwise spiral direction and a spiral groove flow passage with a counterclockwise spiral direction are provided inside a spindle. When the spindle is accelerated to rotate in the forward rotation direction, a pressure in the direction of causing a reverse flow of a coolant is applied to the left-hand spiral groove flow passage by the axial-flow pumping action, but a pressure in the forward direction is applied to the right-hand spiral groove flow passage by the same axial-flow pumping action to cancel out the pressure causing the reverse flow described above.

Abstract: A numerical control apparatus includes a program analyzing unit 19 that extracts a command rotational speed of a rotary shaft from a machining program, an optimum rotational speed recording unit 16 that stores a plurality of optimum rotational speeds that are suitable to suppress chattering vibrations, and a command rotational speed substitutability determination unit 17. The command rotational speed substitutability determination unit obtains a substitute rotational speed range that represents a range of a substitutable optimum rotational speed based on the command rotational speed extracted from the machining program, and selects an optimum rotational speed from among the plurality of optimum rotational speeds stored in the optimum rotational speed recording unit, which falls within the substitute rotational speed range, as a command rotational speed to be actually used in processing.

Abstract: To provide a method to carry out complicated surface machining such as graining or the like without decreasing machining accuracy and machining efficiency. In a machine tool including a main spindle head capable of relatively moving in three perpendicular directions with respect to a workpiece and an additional spindle being provided at the main spindle head and capable of moving in a Z spindle direction, while the main spindle head relatively moves with respect to a working surface S of the workpiece along a smoothly curved surface R which is smoothed so as to be restricted within the movement distance in the moving direction of the additional spindle, the additional spindle moves by a difference between the working surface S and the smoothly curved surface R, and makes a tool T to machine the working surface S.

Abstract: A position control apparatus calculates a position detection value by adding an output of a first-order delay circuit 17 that receives a difference between a driven member position detection value Pl and a motor position detection value Pm to the motor position detection value Pm, and uses the obtained position detection value as a position feedback value. An aging corrector 30 suppresses low frequency vibrations by controlling a time constant Tp of the first-order delay circuit 17 in such a way as to increase the time constant when a vibratory state of the driven member is detected.

Abstract: 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.

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.

Abstract: A thermal displacement correcting apparatus includes a correction amount estimating device and a parameter automatic selecting device that, in a machine tool having two different sets of specifications that differ due to the presence/absence of a scale and different methods of measuring the lengths of a bed and a table, estimate a thermal displacement correction amount of the machine tool of each set of specifications. The two devices store a collection of parameters for an estimated thermal displacement calculation corresponding to each of the bed, the scale, the table, and a workpiece, as a database, and select the parameters belonging to the set of specifications from the database based on machine information according to each set of specifications, calculate estimated thermal displacements of the bed, the table, and the workpiece, or also the scale, according to the selected parameters, and combine the estimated thermal displacements.

Abstract: 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.

Abstract: A motor magnetic pole position correction method includes preventing a movement of a movable element of a direct drive motor by mechanical brake (step S9), generating a command that designates a position spaced or separated from the present position (step S10), detecting a torque command value of the direct drive motor (step S12), determining a magnetic pole position correction value based on a comparison between the detected torque command value and a predetermined threshold value (steps S14 and S16), storing the determined magnetic pole position correction value in a memory (step S18), and performing motor control using an electrical angle offset value obtained based on the magnetic pole position correction value stored in the memory.