WO2010095668A1 - Machine tool and machining method - Google Patents

Machine tool and machining method Download PDF

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Publication number
WO2010095668A1
WO2010095668A1 PCT/JP2010/052381 JP2010052381W WO2010095668A1 WO 2010095668 A1 WO2010095668 A1 WO 2010095668A1 JP 2010052381 W JP2010052381 W JP 2010052381W WO 2010095668 A1 WO2010095668 A1 WO 2010095668A1
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WO
WIPO (PCT)
Prior art keywords
feedback gain
speed feedback
angle
speed
workpiece
Prior art date
Application number
PCT/JP2010/052381
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French (fr)
Japanese (ja)
Inventor
淳司 井上
博文 鹿毛
Original Assignee
三菱重工業株式会社
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Filing date
Publication date
Application filed by 三菱重工業株式会社 filed Critical 三菱重工業株式会社
Publication of WO2010095668A1 publication Critical patent/WO2010095668A1/en

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/19—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
    • G05B19/21—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device
    • G05B19/23—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device for point-to-point control
    • G05B19/231—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device for point-to-point control the positional error is used to control continuously the servomotor according to its magnitude
    • G05B19/232—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path using an incremental digital measuring device for point-to-point control the positional error is used to control continuously the servomotor according to its magnitude with speed feedback only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23F—MAKING GEARS OR TOOTHED RACKS
    • B23F23/00—Accessories or equipment combined with or arranged in, or specially designed to form part of, gear-cutting machines
    • B23F23/12—Other devices, e.g. tool holders; Checking devices for controlling workpieces in machines for manufacturing gear teeth
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/42—Servomotor, servo controller kind till VSS
    • G05B2219/42077—Position, speed or current, combined with vibration feedback

Definitions

  • the present invention relates to a machine tool and a machining method, and more particularly to a machine tool and a machining method used when machining gears.
  • FIG. 1 shows a known machine tool.
  • the machine tool 101 includes a machine tool main body 102 and a machine tool control device 103.
  • the machine tool main body 102 includes a table 105, a cutter 106, a motor 107, a worm gear 108, and an encoder 109.
  • the table 105 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction.
  • the table 105 has a support surface that is perpendicular to the rotation axis thereof, and supports the workpiece 110 that contacts the support surface.
  • the workpiece 110 is generally formed in a disc shape.
  • the cutter 106 is a hob, and is rotated by being controlled by a numerical control device (not shown) to cut the edge of the workpiece 110 and form teeth on the edge of the workpiece 110 to form the workpiece 110 into a gear.
  • the motor 107 includes a shaft that is rotatably supported, and rotates the shaft based on an operation amount output from the machine tool control device 103.
  • the worm gear 108 transmits the rotational power of the shaft of the motor 107 to the table 105 to rotate the table 105.
  • the encoder 109 measures the rotational speed of the shaft of the motor 107 and outputs the rotational speed to the machine tool control device 103.
  • the machine tool control device 103 includes a target value calculation unit 114, an integrator 115, and a control device 117.
  • the target value calculation unit 114 collects numerical control data for processing the workpiece 110 into a gear and the operation of the cutter 106, and calculates a target angle based on the numerical control data and the operation.
  • the integrator 115 calculates the angle of the table 105 by integrating the rotational speed of the shaft of the motor 107 measured by the encoder 109.
  • the control device 117 includes an angle difference calculation unit 121, an angle feedback gain multiplication unit 122, a rotation speed difference calculation unit 123, a speed feedback gain multiplication unit 124, a proportional control unit 125, an integration control unit 126, and an addition unit 127. .
  • the angle difference calculation unit 121 calculates the angle difference by subtracting the angle of the table 105 calculated by the integrator 115 from the target angle calculated by the target value calculation unit 114.
  • the angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount.
  • the rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 107 measured by the encoder 109 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122.
  • the speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain.
  • the proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain.
  • the integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated.
  • the adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
  • the worker places the workpiece 110 on the table 105 and inputs numerical control data for processing the workpiece 110 into a gear into a numerical control device (not shown).
  • the numerical control device outputs the numerical control data to the machine tool control device 103, and rotates the cutter 106 based on the numerical control data.
  • the target value calculation unit 114 of the machine tool control device 103 calculates a target angle based on the numerical control data.
  • the integrator 115 of the machine tool control device 103 calculates the angle of the table 105 based on the rotational speed of the shaft of the motor 107 measured by the encoder 109.
  • the angle difference calculation unit 121 of the control device 117 calculates the angle difference by subtracting the angle of the table 105 calculated by the integrator 115 from the target angle calculated by the target value calculation unit 114.
  • the angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount.
  • the rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 107 measured by the encoder 109 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122.
  • the speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain.
  • the proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain.
  • the integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated.
  • the adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
  • the motor 107 rotates the shaft based on the operation amount calculated by the adding unit 127.
  • the worm gear 108 transmits the rotational power of the shaft of the motor 107 to the table 105 to rotate the table 105.
  • the machine tool 101 forms the workpiece 110 into a gear by the cutter 106 cutting the edge of the workpiece 110 and forming teeth on the edge of the workpiece 110 as indicated by the numerical control data.
  • FIG. 2 shows another known machine tool.
  • the machine tool 131 includes a machine tool main body 132 and a machine tool control device 133.
  • the machine tool main body 132 includes a table 135, a cutter 136, a direct drive motor 137, and a rotary encoder 138.
  • the table 135 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction.
  • the table 135 has a support surface that is perpendicular to the rotation axis thereof, and supports the work 139 that contacts the support surface.
  • the work 139 is formed in a generally disc shape.
  • the cutter 136 is controlled by a numerical control device (not shown) to rotate, thereby cutting the edge of the work 139 and forming teeth on the edge of the work 139 to form the work 139 into a gear.
  • the direct drive motor 137 includes a direct drive motor rotor 141 and a direct drive motor stator 142.
  • the direct drive motor rotor 141 is fixed to the table 135.
  • the direct drive motor stator 142 is fixed to the base.
  • the direct drive motor 137 rotates the table 135 based on the operation amount output from the machine tool control device 133.
  • the rotary encoder 138 measures the angle of the table 135 and outputs the angle to
  • the machine tool control device 133 includes a target value calculation unit 114, a differentiator 145, and a control device 117.
  • the target value calculation unit 114 calculates a target angle based on the numerical control data in order to process the workpiece 139 into a gear.
  • the differentiator 145 calculates the rotational speed of the table 135 by differentiating the angle of the table 135 measured by the rotary encoder 138.
  • the control device 117 includes an angle difference calculation unit 121, an angle feedback gain multiplication unit 122, a rotation speed difference calculation unit 123, a speed feedback gain multiplication unit 124, a proportional control unit 125, an integration control unit 126, and an addition unit 127. .
  • the angle difference calculation unit 121 calculates the angle difference by subtracting the angle of the table 135 measured by the rotary encoder 138 from the target angle calculated by the target value calculation unit 114.
  • the angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount.
  • the rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the table 135 calculated by the differentiator 145 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122.
  • the speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain.
  • the proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain.
  • the integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated.
  • the adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
  • the machining method according to the present invention is executed using the machine tool 131.
  • the operator places the work 139 on the table 135 and inputs numerical control data for processing the work 139 into a gear into a numerical control device (not shown).
  • the numerical control device outputs the numerical control data to the machine tool control device 133, and rotates the cutter 136 based on the numerical control data.
  • the target value calculation unit 114 of the machine tool control device 133 calculates a target angle based on the numerical control data.
  • the differentiator 145 of the machine tool control device 133 calculates the rotation speed of the table 135 based on the rotation angle of the table 135 measured by the rotary encoder 138.
  • the angle difference calculation unit 121 of the control device 117 calculates the angle difference by subtracting the angle of the table 135 calculated by the differentiator 145 from the target angle calculated by the target value calculation unit 114.
  • the angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount.
  • the rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the table 135 calculated by the differentiator 145 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122.
  • the speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain.
  • the proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain.
  • the integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated.
  • the adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
  • the direct drive motor 137 rotates the table 135 based on the operation amount calculated by the adding unit 127. With such an operation, the machine tool 131 forms the workpiece 139 into a gear by the cutter 136 cutting the edge of the workpiece 139 and forming teeth on the edge of the workpiece 139 as indicated by the numerical control data.
  • Such machine tools can secure the rigidity in the table rotation direction against an external force acting on the workpiece by adjusting the constant of the feedback control system, for example, by increasing the gain of the speed feedback.
  • the gain is set high, a vibration phenomenon caused by the control system occurs.
  • machine tools such as these set constants so that vibration phenomena caused by the control system do not occur when machining all target workpieces, and all control constants are fixed at the time of shipment. Yes.
  • a machine tool is desired to ensure the rigidity in the rotational direction of the table against an external force acting on the workpiece and to prevent an oscillation phenomenon.
  • Japanese Patent No. 2996943 discloses a gear machining apparatus that increases machining efficiency by accurately detecting the completion of machining of a gear to be machined and ending the machining.
  • the gear machining apparatus includes a motor for driving a cutter gear and a gear to be machined, an encoder for detecting rotation of each of the motors, PLL control means for controlling the motors to rotate in synchronization with each other, a cutter
  • the PLL control unit includes a shift unit that sequentially shifts the rotational phases of the two motors according to a processing amount of the gear to be processed by the gear, and a unit that detects vibration in the processing unit. It is a jitter amount detecting means for detecting a phase fluctuation state of an input pulse from the encoder with respect to a command reference pulse given to each of the motors.
  • Japanese Patent Application Laid-Open No. 07-88746 discloses in-process abnormalities during cutting (for example, increased wear or damage to the cutting edge of the tool) by detecting the machine with a simple device and with simple modifications.
  • a cutting abnormality detection and emergency return method is disclosed in a gear processing machine, which measures the damage of the tool and machine and prevents the defect of the workpiece.
  • the cutting abnormality detection and emergency return method in the gear processing machine is a gear processing machine that performs cutting while rotating a tool and a gear material to be processed at a constant rotation ratio. And a magnetoelectric or photoelectric detector, and by measuring fluctuations in the rotational frequency of the tool drive shaft, it is compared with the rotational frequency during normal cutting to detect abnormalities in the cutting state.
  • An object of the present invention is to provide a machine tool and a machining method that ensure rigidity in the rotation direction of a table against an external force acting on a workpiece and prevent an oscillation phenomenon.
  • a machine tool includes a speed feedback gain automatic setting device that automatically updates a speed feedback gain, a sensor that measures a sensor value related to rotation of a table that supports a workpiece, and the angle of the table matches a target angle.
  • a control device that feedback-controls a motor that rotates the table based on the sensor value based on the speed feedback gain.
  • Such a machine tool has a variable speed feedback gain, and when the appropriate value is substituted for the speed feedback gain, it ensures the rigidity in the rotational direction of the table against the external force acting on the workpiece. In addition, the oscillation phenomenon can be prevented.
  • the speed feedback gain automatic setting device includes a vibration measuring unit that calculates the degree of vibration based on the sensor value, and a speed feedback gain calculating unit that calculates the speed feedback gain based on the degree of vibration. It is preferable.
  • the speed feedback gain is preferably increased when the degree of vibration is greater than a predetermined threshold.
  • the sensor preferably includes a rotary encoder that measures the angle of the table. At this time, the sensor value indicates the angle of the table.
  • the machine tool according to the present invention further includes a target value calculation unit that calculates a target angle based on numerical control data for forming a gear on the workpiece. That is, such a machine tool is suitable for a gear processing machine that creates gears.
  • the speed feedback gain automatic setting device refers to a workpiece material type collection unit that collects the material type of the workpiece, and a table that associates a plurality of material types with a plurality of speed feedback gains, and determines the speed feedback gain from the plurality of speed feedback gains. And a speed feedback gain calculating unit that calculates the speed feedback gain corresponding to the material type.
  • the workpiece material type collection unit extracts the material type from the data for processing the workpiece.
  • the machining method includes a step of automatically updating a speed feedback gain, a step of measuring a sensor value related to rotation of a table supporting a workpiece, and a speed of the table so that the angle of the table matches a target angle. Feedback control of a motor for rotating the table based on the feedback gain based on the sensor value.
  • the speed feedback gain is variable, and when an appropriate value is substituted for the speed feedback gain, the rigidity in the rotational direction of the table is secured against the external force acting on the workpiece. In addition, the oscillation phenomenon can be prevented.
  • the processing method according to the present invention further includes a step of calculating the degree of vibration based on the sensor value and a step of calculating the speed feedback gain based on the degree of vibration.
  • the speed feedback gain is preferably increased when the degree of vibration is greater than a predetermined threshold.
  • the sensor preferably includes a rotary encoder that measures the angle of the table. At this time, the sensor value indicates the angle of the table.
  • the machining method according to the present invention further includes a step of calculating the target angle based on numerical control data for forming a gear on the workpiece. That is, such a machine tool is suitable for a gear processing machine that creates gears.
  • the machining method according to the present invention refers to a step of collecting the material type of the workpiece and a table associating a plurality of material types and a plurality of speed feedback gains, and corresponding to the material type out of the plurality of speed feedback gains.
  • the method further comprises a step of calculating a speed feedback gain.
  • the machining method according to the present invention preferably further includes a step of extracting the material type from data for machining the workpiece.
  • the machine tool and the machining method according to the present invention can ensure the rigidity in the rotation direction of the table against an external force acting on the workpiece and can prevent an oscillation phenomenon.
  • FIG. 1 is a block diagram showing a known machine tool.
  • FIG. 2 is a block diagram showing another known machine tool.
  • FIG. 3 is a block diagram showing an embodiment of a machine tool according to the present invention.
  • FIG. 4 is a graph showing changes in rigidity (compliance) when the table rotates when feedback controlling the motor using various speed feedback gains.
  • FIG. 5 is a block diagram showing another embodiment of the machine tool according to the present invention.
  • FIG. 6 is a block diagram showing another embodiment of the machine tool according to the present invention.
  • the machine tool 1 includes a machine tool body 2 and a machine tool control device 3 as shown in FIG.
  • the machine tool main body 2 includes a table 5, a cutter 6, a motor 7, a worm gear 8, a rotary encoder 9, and an encoder 10.
  • the table 5 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction.
  • the table 5 has a support surface that is perpendicular to the rotation axis thereof, and supports the workpiece 11 that contacts the support surface.
  • the workpiece 11 is generally formed in a disc shape.
  • the cutter 6 is controlled and rotated by a numerical control device (not shown) to cut the edge of the workpiece 11 and form teeth on the edge of the workpiece 11 to form the workpiece 11 into a gear.
  • the motor 7 includes a shaft that is rotatably supported, and rotates the shaft based on an operation amount output from the machine tool control device 3.
  • the worm gear 8 transmits the rotational power of the shaft of the motor 7 to the table 5 and rotates the table 5.
  • the rotary encoder 9 measures the angle of the table 5 and outputs the angle to the machine tool control device 3.
  • the encoder 10 measures the rotational speed of the shaft of the motor 7 and outputs the rotational speed to the machine tool
  • the machine tool control device 3 includes a target value calculation unit 14, an integrator 15, a speed feedback gain setting device 16, and a control device 17.
  • the target value calculation unit 14 collects numerical control data for processing the workpiece 11 into a gear and the operation of the cutter 6 and calculates a target angle based on the numerical control data and the operation.
  • the integrator 15 calculates the angle of the table 5 by integrating the rotational speed of the shaft of the motor 7 measured by the encoder 10.
  • the speed feedback gain setting device 16 updates the speed feedback gain based on the angle of the table 5 measured by the rotary encoder 9. That is, the speed feedback gain setting device 16 includes a vibration measuring unit 28 and a speed feedback gain calculating unit 29.
  • the vibration measuring unit 28 calculates the degree of vibration of the table 5 based on the angle of the table 5 measured by the rotary encoder 9.
  • the speed feedback gain calculation unit 29 calculates a speed feedback gain based on the degree of vibration calculated by the vibration measurement unit 28.
  • the speed feedback gain calculation unit 29 includes a storage device that records a threshold value and a plurality of speed feedback gains.
  • the speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among the plurality of speed feedback gains.
  • the speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold.
  • Output speed feedback gain That is, the speed feedback gain setting device 16 outputs only one of the plurality of speed feedback gains, and the speed feedback gain output by the speed feedback gain setting device 16 has an upper limit value and a lower limit value. .
  • the speed feedback gain calculation unit 29 further selects a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value. When not included, it is determined as abnormal and the machine tool body 2 is stopped.
  • the control device 17 uses the target angle calculated by the target value calculation unit 14, the angle of the table 5 calculated by the integrator 15, the rotational speed of the shaft of the motor 7 measured by the encoder 10, and the speed feedback gain setting device 16. Based on the set speed feedback gain, the motor 7 is feedback-controlled so that the angle of the table 5 matches the target angle calculated by the target value calculation unit 14.
  • control device 17 includes an angle difference calculation unit 21, an angle feedback gain multiplication unit 22, a rotation speed difference calculation unit 23, a speed feedback gain multiplication unit 24, a proportional control unit 25, an integration control unit 26, and an addition unit 27. ing.
  • the angle difference calculation unit 21 calculates the angle difference by subtracting the angle of the table 5 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14.
  • the angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant.
  • the rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 7 measured by the encoder 10 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22.
  • the speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16.
  • the proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain.
  • the integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated.
  • the adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26. The amount of operation matches the amount of operation output by the control device 17.
  • the embodiment of the machining method according to the present invention is executed using the machine tool 1.
  • the worker places the workpiece 11 on the table 5 and inputs numerical control data for processing the workpiece 11 into a gear into a numerical control device (not shown).
  • the numerical control device outputs the numerical control data to the machine tool control device 3, and rotates the cutter 6 based on the numerical control data.
  • the target value calculation unit 14 of the machine tool control device 3 collects the numerical control data and the operation of the cutter 6 and calculates a target angle based on the numerical control data and the operation.
  • the integrator 15 of the machine tool control device 3 calculates the angle of the table 5 based on the rotational speed of the shaft of the motor 7 measured by the encoder 10.
  • the vibration measuring unit 28 of the speed feedback gain setting device 16 calculates the degree of vibration of the table 5 based on the angle of the table 5 measured by the rotary encoder 9.
  • the speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among a plurality of speed feedback gains recorded in advance in the storage device.
  • the speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold. Output speed feedback gain.
  • the angle difference calculation unit 21 of the control device 17 calculates the angle difference by subtracting the angle of the table 5 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14.
  • the angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant.
  • the rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 7 measured by the encoder 10 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22.
  • the speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16.
  • the proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain.
  • the integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated.
  • the adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
  • the motor 7 rotates the shaft based on the operation amount calculated by the adding unit 27.
  • the worm gear 8 transmits the rotational power of the shaft of the motor 7 to the table 5 and rotates the table 5. With this operation, the machine tool 1 forms the workpiece 11 into a gear by the cutter 6 cutting the edge of the workpiece 11 and forming teeth on the edge of the workpiece 11 as shown in the numerical control data.
  • the speed feedback gain calculation unit 29 has a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output, and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value.
  • the machine tool control device 3 can prevent the table drive system from causing an oscillation phenomenon and becoming uncontrollable.
  • FIG. 4 shows a change in rigidity (compliance) when the table 5 rotates when the motor 7 is feedback-controlled using a plurality of speed feedback gains.
  • the change 31 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain indicating a certain value.
  • the change 32 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 31 is indicated.
  • the change 33 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 32 is indicated.
  • the change 34 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 33 is indicated.
  • the change 35 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 34 is indicated.
  • Changes 31 to 35 indicate that the velocity feedback gain used for feedback control changes with respect to the frequency of the disturbance when the value is a certain value.
  • the changes 31 to 35 further indicate that the rigidity when the table 5 rotates when the speed feedback gain is increased, and that the rotation of the table 5 is less affected by disturbance. .
  • the machine tool 1 can automatically adjust the control constant (speed feedback gain) until the vibration of the workpiece 11 generated during gear machining falls within the threshold value by executing such an operation. For this reason, the machine tool 1 can ensure the rigidity of the rotation direction of the table 5 with respect to the external force acting on the workpiece 11, and can prevent an oscillation phenomenon caused by the control system.
  • the vibration measurement unit 28 can be replaced with another vibration measurement unit that calculates the degree of vibration of the table 5 based on the angle of the table 5 calculated by the integrator 15.
  • Such a machine tool can ensure the rigidity in the rotation direction of the table 5 with respect to the external force acting on the workpiece 11 as well as the machine tool 1 in the above-described embodiment, and is caused by the control system. Oscillation phenomenon can be prevented.
  • Such a machine tool can further omit the rotary encoder 9 and can be manufactured at a lower cost.
  • the speed feedback gain calculation unit 29 can be replaced with another speed feedback gain calculation unit that calculates a speed feedback gain corresponding to the degree of vibration calculated by the vibration measurement unit 28.
  • Such a machine tool can ensure the rigidity in the rotation direction of the table 5 with respect to the external force acting on the workpiece 11 as well as the machine tool 1 in the above-described embodiment, and is caused by the control system. Oscillation phenomenon can be prevented.
  • FIG. 5 shows another embodiment of the machine tool according to the present invention.
  • the machine tool 41 includes a machine tool main body 42 and a machine tool control device 43.
  • the machine tool main body 42 includes a table 45, a cutter 46, a direct drive motor 47, and a rotary encoder 48.
  • the table 45 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction.
  • the table 45 has a support surface that is perpendicular to the rotation axis thereof, and supports a work 49 that contacts the support surface.
  • the work 49 is formed in a generally disc shape.
  • the cutter 46 is formed of a hob-type grindstone, and is rotated by being controlled by a numerical control device (not shown) to cut the edge of the workpiece 49, and by forming teeth on the edge of the workpiece 49, the workpiece 49 is turned into a gear.
  • the direct drive motor 47 includes a direct drive motor rotor 51 and a direct drive motor stator 52.
  • the direct drive motor rotor 51 is fixed to the table 45.
  • the direct drive motor stator 52 is fixed to the base.
  • the direct drive motor 47 rotates the table 45 based on the operation amount output from the machine tool control device 43.
  • the rotary encoder 48 measures the angle of the table 45 and outputs the angle to the machine tool control device 43.
  • the machine tool control device 43 includes a target value calculation unit 14, a differentiator 55, a speed feedback gain setting device 16, and a control device 17.
  • the target value calculation unit 14 collects numerical control data for processing the workpiece 49 into a gear and the operation of the cutter 46, and calculates a target angle based on the numerical control data and the operation.
  • the differentiator 55 calculates the rotational speed of the table 45 by differentiating the angle of the table 45 measured by the rotary encoder 48.
  • the speed feedback gain setting device 16 includes a vibration measuring unit 28 and a speed feedback gain calculating unit 29.
  • the vibration measuring unit 28 calculates the degree of vibration of the table 45 based on the angle of the table 45 measured by the rotary encoder 48.
  • the speed feedback gain calculation unit 29 includes a storage device that records a threshold value and a plurality of speed feedback gains.
  • the speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among the plurality of speed feedback gains.
  • the speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold.
  • Output speed feedback gain That is, the speed feedback gain setting device 16 outputs only one of the plurality of speed feedback gains, and the speed feedback gain output by the speed feedback gain setting device 16 has an upper limit value and a lower limit value. .
  • the speed feedback gain calculation unit 29 further selects a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value. When not included, it is determined as abnormal and the machine tool main body 42 is stopped.
  • the control device 17 includes an angle difference calculation unit 21, an angle feedback gain multiplication unit 22, a rotational speed difference calculation unit 23, a speed feedback gain multiplication unit 24, a proportional control unit 25, an integration control unit 26, and an addition unit 27. .
  • the angle difference calculation unit 21 calculates the angle difference by subtracting the angle of the table 45 measured by the rotary encoder 48 from the target angle calculated by the target value calculation unit 14.
  • the angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant.
  • the rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the table 45 calculated by the differentiator 55 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22.
  • the speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16.
  • the proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain.
  • the integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated.
  • the adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
  • the embodiment of the machining method according to the present invention is executed using the machine tool 41.
  • the worker places the workpiece 49 on the table 45, and inputs numerical control data for processing the workpiece 49 into a gear into a numerical controller (not shown).
  • the numerical control device outputs the numerical control data to the machine tool control device 43, and rotates the cutter 46 based on the numerical control data.
  • the target value calculation unit 14 of the machine tool control device 43 calculates a target angle based on the numerical control data.
  • the differentiator 55 of the machine tool control device 43 calculates the rotation speed of the table 45 based on the rotation angle of the table 45 measured by the rotary encoder 48.
  • the vibration measuring unit 28 of the speed feedback gain setting device 16 calculates the degree of vibration of the table 45 based on the angle of the table 45 measured by the rotary encoder 48.
  • the speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among a plurality of speed feedback gains recorded in advance in the storage device.
  • the speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold. Output speed feedback gain.
  • the angle difference calculation unit 21 of the control device 17 calculates the angle difference by subtracting the angle of the table 45 calculated by the differentiator 55 from the target angle calculated by the target value calculation unit 14.
  • the angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant.
  • the rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the table 45 calculated by the differentiator 55 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22.
  • the speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16.
  • the proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain.
  • the integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated.
  • the adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
  • the direct drive motor 47 rotates the table 45 based on the operation amount calculated by the adding unit 27. With this operation, the machine tool 41 forms the workpiece 49 into a gear by the cutter 46 cutting the edge of the workpiece 49 and forming teeth on the edge of the workpiece 49 as shown in the numerical control data.
  • the speed feedback gain calculation unit 29 has a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output, and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value.
  • the machine tool control device 43 can prevent the table drive system from causing an oscillation phenomenon and becoming uncontrollable.
  • such a machine tool 41 performs such an operation, and in the same manner as the machine tool 1 in the above-described embodiment, provides the rigidity in the rotation direction of the table 45 with respect to the external force acting on the workpiece 49.
  • the oscillation phenomenon caused by the control system can be prevented. That is, such a processing method can also be applied to control of the direct drive motor 47 that is directly connected to the table 45 and rotates the table 45.
  • FIG. 6 shows still another embodiment of the machine tool according to the present invention.
  • the machine tool 61 includes a machine tool main body 62 and a machine tool control device 63.
  • the machine tool main body 62 includes a table 65, a cutter 66, a motor 67, a worm gear 68, and an encoder 69.
  • the table 65 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction.
  • the table 65 has a support surface that is perpendicular to the rotation axis thereof, and supports the work 70 that contacts the support surface.
  • the workpiece 70 is generally formed in a disc shape.
  • the cutter 66 is controlled and rotated by a numerical control device (not shown) to cut the edge of the work 70 and form teeth on the edge of the work 70 to form the work 70 into a gear.
  • the motor 67 includes a shaft that is rotatably supported, and rotates the shaft based on an operation amount output from the machine tool control device 63.
  • the worm gear 68 transmits the rotational power of the shaft of the motor 67 to the table 65 to rotate the table 65.
  • the encoder 69 measures the rotational speed of the shaft of the motor 67 and outputs the rotational speed to the machine tool control device 63.
  • the machine tool control device 63 includes a target value calculation unit 14, an integrator 15, a speed feedback gain setting device 71, and a control device 17.
  • the target value calculation unit 14 collects numerical control data for processing the workpiece 70 into a gear and the operation of the cutter 66, and calculates a target angle based on the numerical control data and the operation.
  • the integrator 15 calculates the angle of the table 65 by integrating the rotational speed of the shaft of the motor 67 measured by the encoder 69.
  • the speed feedback gain setting device 71 calculates a speed feedback gain based on the numerical control data. That is, the speed feedback gain setting device 71 includes a workpiece material type collection unit 72 and a speed feedback gain calculation unit 73.
  • the workpiece material type collecting unit 72 analyzes the numerical control data and extracts the material type of the workpiece 70 from the numerical control data.
  • the speed feedback gain calculation unit 73 includes a storage device that records a table associating the material type set and the speed feedback gain set. That is, an arbitrary element in the grade set corresponds to one element in the speed feedback gain set. Each element of the material type set indicates the material type of the material applied to the workpiece 70. Each element of the speed feedback gain set indicates the value of the speed feedback gain used in the control device 17.
  • the speed feedback gain calculation unit 73 refers to the table and calculates a speed feedback gain corresponding to the material type extracted by the workpiece material type collection unit 72 from the speed feedback gain set.
  • the control device 17 includes an angle difference calculation unit 21, an angle feedback gain multiplication unit 22, a rotational speed difference calculation unit 23, a speed feedback gain multiplication unit 24, a proportional control unit 25, an integration control unit 26, and an addition unit 27. .
  • the angle difference calculation unit 21 calculates the angle difference by subtracting the angle of the table 65 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14.
  • the angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant.
  • the rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 67 measured by the encoder 69 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22.
  • the speed feedback gain multiplication unit 24 multiplies the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain calculated by the speed feedback gain calculation unit 73 to calculate the speed operation amount.
  • the proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain.
  • the integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated.
  • the adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
  • the embodiment of the machining method according to the present invention is executed using the machine tool 61.
  • the operator places the work 70 on the table 65, and inputs numerical control data for processing the work 70 into a gear into a numerical control device (not shown).
  • the numerical control device outputs the numerical control data to the machine tool control device 63, and rotates the cutter 66 based on the numerical control data.
  • the target value calculation unit 14 of the machine tool control device 63 collects the numerical control data and the operation of the cutter 66 and calculates a target angle based on the numerical control data and the operation of the cutter 66.
  • the integrator 15 of the machine tool control device 63 calculates the angle of the table 65 based on the rotational speed of the shaft of the motor 67 measured by the encoder 69.
  • the workpiece material type collection unit 72 of the speed feedback gain setting device 71 calculates the material type of the material of the workpiece 70 based on the numerical control data.
  • the speed feedback gain calculation unit 73 refers to a table associating the material type set with the speed feedback gain set, and the material extracted from the speed feedback gain set by the work material type collection unit 72 is referred to by the speed feedback gain calculation unit 73. The speed feedback gain corresponding to the seed is calculated.
  • the angle difference calculation unit 21 of the control device 17 calculates the angle difference by subtracting the angle of the table 65 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14.
  • the angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant.
  • the rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 67 measured by the encoder 69 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22.
  • the speed feedback gain multiplication unit 24 calculates the speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 71.
  • the proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain.
  • the integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated.
  • the adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
  • the motor 67 rotates the shaft based on the operation amount calculated by the adding unit 27.
  • the worm gear 68 transmits the rotational power of the shaft of the motor 67 to the table 65 to rotate the table 65.
  • the machine tool 61 forms the workpiece 70 into a gear by the cutter 66 cutting the edge of the workpiece 70 and forming teeth on the edge of the workpiece 70 as shown in the numerical control data.
  • the rigidity in the rotational direction of the table 65 with respect to the external force acting on the work 70 varies depending on the machinability and grindability of the work 70.
  • the machinability and grindability are specific to the material type of the material forming the workpiece 70.
  • the machine tool 61 can set the speed feedback gain more appropriately by appropriately creating the table recorded by the speed feedback gain calculator 73.
  • the speed feedback gain is appropriately set in this way, the machine tool 61 can ensure the rigidity in the rotational direction of the table 65 with respect to the external force acting on the workpiece 70, and oscillation caused by the control system The phenomenon can be prevented.
  • the workpiece material type collecting unit 72 can be replaced with another workpiece material type collecting unit that collects the material type input via the input device included in the machine tool control device 63 from the input device.
  • the speed feedback gain can be set more appropriately in the same manner as the machine tool 61 in the above-described embodiment, and the rigidity in the rotation direction of the table 65 with respect to the external force acting on the workpiece 70 can be increased. The oscillation phenomenon caused by the control system can be prevented.
  • the speed feedback gain setting device 71 initially calculates the speed feedback gain based on the material type of the workpiece 70, and thereafter, based on the vibration of the table 65, as in the above-described embodiment. A speed feedback gain can also be calculated. Also in the calculation of the speed feedback gain, the oscillation phenomenon can be prevented in the same manner as in the above-described embodiment.

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Abstract

A machine tool is equipped with an automatic speed feedback gain setter which updates the speed feedback gain automatically, a sensor which measures the rotational speed of a motor which rotates a table supporting a work, and a controller performing feedback control of the motor based on the rotational speed thereof so that the angle of the table coincides with a target angle based on the speed feedback gain. The machine tool has a variable speed feedback gain and when a proper value is substituted in the speed feedback gain, rigidity in the rotational direction of the table is ensured against the external force acting on the work and oscillation phenomenon can be prevented.

Description

工作機械および加工方法Machine tool and processing method
　本発明は、工作機械および加工方法に関し、特に、歯車を加工するときに利用される工作機械および加工方法に関する。 The present invention relates to a machine tool and a machining method, and more particularly to a machine tool and a machining method used when machining gears.
　ホブを利用して歯車を形成する工作機械が知られている。ホブ加工では、ホブカッタと同期してワークを回転させることで、ワークの全周に歯車が形成される。すなわち、ホブカッタとワークとを駆動する両駆動装置とも、目標値に対し変位と速度をフィードバックすることで、目標値に追従させている。 Machine tools that form gears using hobbs are known. In hobbing, a gear is formed on the entire circumference of the workpiece by rotating the workpiece in synchronization with the hob cutter. That is, both the drive devices for driving the hob cutter and the workpiece are made to follow the target value by feeding back the displacement and speed to the target value.
　図１は、公知の工作機械を示している。その工作機械１０１は、工作機械本体１０２と工作機械制御装置１０３とを備えている。工作機械本体１０２は、テーブル１０５とカッター１０６とモータ１０７とウォームギア１０８とエンコーダ１０９とを備えている。 FIG. 1 shows a known machine tool. The machine tool 101 includes a machine tool main body 102 and a machine tool control device 103. The machine tool main body 102 includes a table 105, a cutter 106, a motor 107, a worm gear 108, and an encoder 109.
　テーブル１０５は、鉛直方向に平行である回転軸を中心に回転可能に土台に支持されている。テーブル１０５は、その回転軸に垂直である支持面を有し、その支持面に接触するワーク１１０を支持する。ワーク１１０は、概ね円盤状に形成されている。カッター１０６は、ホブであり、図示されていない数値制御装置により制御されて回転することによりワーク１１０の縁を切削し、ワーク１１０の縁に歯を形成することによりワーク１１０を歯車に形成する。モータ１０７は、回転可能に支持されるシャフトを備え、工作機械制御装置１０３から出力される操作量に基づいてそのシャフトを回転させる。ウォームギア１０８は、モータ１０７のシャフトの回転動力をテーブル１０５に伝達し、テーブル１０５を回転させる。エンコーダ１０９は、モータ１０７のシャフトの回転速度を計測し、その回転速度を工作機械制御装置１０３に出力する。 The table 105 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction. The table 105 has a support surface that is perpendicular to the rotation axis thereof, and supports the workpiece 110 that contacts the support surface. The workpiece 110 is generally formed in a disc shape. The cutter 106 is a hob, and is rotated by being controlled by a numerical control device (not shown) to cut the edge of the workpiece 110 and form teeth on the edge of the workpiece 110 to form the workpiece 110 into a gear. The motor 107 includes a shaft that is rotatably supported, and rotates the shaft based on an operation amount output from the machine tool control device 103. The worm gear 108 transmits the rotational power of the shaft of the motor 107 to the table 105 to rotate the table 105. The encoder 109 measures the rotational speed of the shaft of the motor 107 and outputs the rotational speed to the machine tool control device 103.
　工作機械制御装置１０３は、目標値算出部１１４と積分器１１５と制御装置１１７とを備えている。目標値算出部１１４は、ワーク１１０を歯車に加工するための数値制御データとカッター１０６の動作とを収集し、その数値制御データと動作とに基づいて目標角度を算出する。積分器１１５は、エンコーダ１０９により計測されるモータ１０７のシャフトの回転速度を積分することにより、テーブル１０５の角度を算出する。 The machine tool control device 103 includes a target value calculation unit 114, an integrator 115, and a control device 117. The target value calculation unit 114 collects numerical control data for processing the workpiece 110 into a gear and the operation of the cutter 106, and calculates a target angle based on the numerical control data and the operation. The integrator 115 calculates the angle of the table 105 by integrating the rotational speed of the shaft of the motor 107 measured by the encoder 109.
　制御装置１１７は、角度差分算出部１２１と角度フィードバックゲイン乗算部１２２と回転速度差分算出部１２３と速度フィードバックゲイン乗算部１２４と比例制御部１２５と積分制御部１２６と加算部１２７とを備えている。 The control device 117 includes an angle difference calculation unit 121, an angle feedback gain multiplication unit 122, a rotation speed difference calculation unit 123, a speed feedback gain multiplication unit 124, a proportional control unit 125, an integration control unit 126, and an addition unit 127. .
　角度差分算出部１２１は、目標値算出部１１４により算出された目標角度から積分器１１５により算出されたテーブル１０５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部１２２は、角度差分算出部１２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部１２３は、角度フィードバックゲイン乗算部１２２により算出された回転速度量からエンコーダ１０９により計測されるモータ１０７のシャフトの回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部１２４は、回転速度差分算出部１２３により算出された回転速度差分に定数である速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部１２５は、速度フィードバックゲイン乗算部１２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部１２６は、速度フィードバックゲイン乗算部１２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部１２７は、比例制御部１２５により算出された比例操作量に積分制御部１２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 121 calculates the angle difference by subtracting the angle of the table 105 calculated by the integrator 115 from the target angle calculated by the target value calculation unit 114. The angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount. The rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 107 measured by the encoder 109 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122. The speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain. The proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain. The integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated. The adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
　作業者は、まず、ワーク１１０をテーブル１０５に設置し、図示されていない数値制御装置にワーク１１０を歯車に加工するための数値制御データを入力する。その数値制御装置は、その数値制御データを工作機械制御装置１０３に出力し、その数値制御データに基づいてカッター１０６を回転させる。工作機械制御装置１０３の目標値算出部１１４は、数値制御データに基づいて目標角度を算出する。工作機械制御装置１０３の積分器１１５は、エンコーダ１０９により計測されるモータ１０７のシャフトの回転速度に基づいてテーブル１０５の角度を算出する。 First, the worker places the workpiece 110 on the table 105 and inputs numerical control data for processing the workpiece 110 into a gear into a numerical control device (not shown). The numerical control device outputs the numerical control data to the machine tool control device 103, and rotates the cutter 106 based on the numerical control data. The target value calculation unit 114 of the machine tool control device 103 calculates a target angle based on the numerical control data. The integrator 115 of the machine tool control device 103 calculates the angle of the table 105 based on the rotational speed of the shaft of the motor 107 measured by the encoder 109.
　制御装置１１７の角度差分算出部１２１は、目標値算出部１１４により算出された目標角度から積分器１１５により算出されたテーブル１０５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部１２２は、角度差分算出部１２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部１２３は、角度フィードバックゲイン乗算部１２２により算出された回転速度量からエンコーダ１０９により計測されるモータ１０７のシャフトの回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部１２４は、回転速度差分算出部１２３により算出された回転速度差分に定数である速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部１２５は、速度フィードバックゲイン乗算部１２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部１２６は、速度フィードバックゲイン乗算部１２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部１２７は、比例制御部１２５により算出された比例操作量に積分制御部１２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 121 of the control device 117 calculates the angle difference by subtracting the angle of the table 105 calculated by the integrator 115 from the target angle calculated by the target value calculation unit 114. The angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount. The rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 107 measured by the encoder 109 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122. The speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain. The proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain. The integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated. The adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
　モータ１０７は、加算部１２７により算出された操作量に基づいてシャフトを回転させる。ウォームギア１０８は、モータ１０７のシャフトの回転動力をテーブル１０５に伝達し、テーブル１０５を回転させる。工作機械１０１は、このような動作により、その数値制御データに示されるようにカッター１０６がワーク１１０の縁を切削し、ワーク１１０の縁に歯を形成することによりワーク１１０を歯車に形成する。 The motor 107 rotates the shaft based on the operation amount calculated by the adding unit 127. The worm gear 108 transmits the rotational power of the shaft of the motor 107 to the table 105 to rotate the table 105. With such an operation, the machine tool 101 forms the workpiece 110 into a gear by the cutter 106 cutting the edge of the workpiece 110 and forming teeth on the edge of the workpiece 110 as indicated by the numerical control data.
　図２は、公知の他の工作機械を示している。その工作機械１３１は、工作機械本体１３２と工作機械制御装置１３３とを備えている。工作機械本体１３２は、テーブル１３５とカッター１３６とダイレクトドライブモータ１３７とロータリーエンコーダ１３８とを備えている。 FIG. 2 shows another known machine tool. The machine tool 131 includes a machine tool main body 132 and a machine tool control device 133. The machine tool main body 132 includes a table 135, a cutter 136, a direct drive motor 137, and a rotary encoder 138.
　テーブル１３５は、鉛直方向に平行である回転軸を中心に回転可能に土台に支持されている。テーブル１３５は、その回転軸に垂直である支持面を有し、その支持面に接触するワーク１３９を支持する。ワーク１３９は、概ね円盤状に形成されている。カッター１３６は、図示されていない数値制御装置により制御されて回転することによりワーク１３９の縁を切削し、ワーク１３９の縁に歯を形成することによりワーク１３９を歯車に形成する。ダイレクトドライブモータ１３７は、ダイレクトドライブモータロータ１４１とダイレクトドライブモータステータ１４２とを備えている。ダイレクトドライブモータロータ１４１は、テーブル１３５に固定されている。ダイレクトドライブモータステータ１４２は、その土台に固定されている。ダイレクトドライブモータ１３７は、工作機械制御装置１３３から出力される操作量に基づいてテーブル１３５を回転させる。ロータリーエンコーダ１３８は、テーブル１３５の角度を計測し、その角度を工作機械制御装置１３３に出力する。 The table 135 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction. The table 135 has a support surface that is perpendicular to the rotation axis thereof, and supports the work 139 that contacts the support surface. The work 139 is formed in a generally disc shape. The cutter 136 is controlled by a numerical control device (not shown) to rotate, thereby cutting the edge of the work 139 and forming teeth on the edge of the work 139 to form the work 139 into a gear. The direct drive motor 137 includes a direct drive motor rotor 141 and a direct drive motor stator 142. The direct drive motor rotor 141 is fixed to the table 135. The direct drive motor stator 142 is fixed to the base. The direct drive motor 137 rotates the table 135 based on the operation amount output from the machine tool control device 133. The rotary encoder 138 measures the angle of the table 135 and outputs the angle to the machine tool control device 133.
　工作機械制御装置１３３は、目標値算出部１１４と微分器１４５と制御装置１１７とを備えている。目標値算出部１１４は、ワーク１３９を歯車に加工するために、数値制御データに基づいて目標角度を算出する。微分器１４５は、ロータリーエンコーダ１３８により計測されるテーブル１３５の角度を微分することにより、テーブル１３５の回転速度を算出する。 The machine tool control device 133 includes a target value calculation unit 114, a differentiator 145, and a control device 117. The target value calculation unit 114 calculates a target angle based on the numerical control data in order to process the workpiece 139 into a gear. The differentiator 145 calculates the rotational speed of the table 135 by differentiating the angle of the table 135 measured by the rotary encoder 138.
　制御装置１１７は、角度差分算出部１２１と角度フィードバックゲイン乗算部１２２と回転速度差分算出部１２３と速度フィードバックゲイン乗算部１２４と比例制御部１２５と積分制御部１２６と加算部１２７とを備えている。 The control device 117 includes an angle difference calculation unit 121, an angle feedback gain multiplication unit 122, a rotation speed difference calculation unit 123, a speed feedback gain multiplication unit 124, a proportional control unit 125, an integration control unit 126, and an addition unit 127. .
　角度差分算出部１２１は、目標値算出部１１４により算出された目標角度からロータリーエンコーダ１３８により計測されるテーブル１３５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部１２２は、角度差分算出部１２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部１２３は、角度フィードバックゲイン乗算部１２２により算出された回転速度量から微分器１４５により算出されたテーブル１３５の回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部１２４は、回転速度差分算出部１２３により算出された回転速度差分に定数である速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部１２５は、速度フィードバックゲイン乗算部１２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部１２６は、速度フィードバックゲイン乗算部１２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部１２７は、比例制御部１２５により算出された比例操作量に積分制御部１２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 121 calculates the angle difference by subtracting the angle of the table 135 measured by the rotary encoder 138 from the target angle calculated by the target value calculation unit 114. The angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount. The rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the table 135 calculated by the differentiator 145 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122. The speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain. The proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain. The integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated. The adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
　本発明による加工方法は、工作機械１３１を用いて実行される。作業者は、まず、ワーク１３９をテーブル１３５に設置し、図示されていない数値制御装置にワーク１３９を歯車に加工するための数値制御データを入力する。その数値制御装置は、その数値制御データを工作機械制御装置１３３に出力し、その数値制御データに基づいてカッター１３６を回転させる。工作機械制御装置１３３の目標値算出部１１４は、数値制御データに基づいて目標角度を算出する。工作機械制御装置１３３の微分器１４５は、ロータリーエンコーダ１３８により計測されたテーブル１３５の回転角度に基づいてテーブル１３５の回転速度を算出する。 The machining method according to the present invention is executed using the machine tool 131. First, the operator places the work 139 on the table 135 and inputs numerical control data for processing the work 139 into a gear into a numerical control device (not shown). The numerical control device outputs the numerical control data to the machine tool control device 133, and rotates the cutter 136 based on the numerical control data. The target value calculation unit 114 of the machine tool control device 133 calculates a target angle based on the numerical control data. The differentiator 145 of the machine tool control device 133 calculates the rotation speed of the table 135 based on the rotation angle of the table 135 measured by the rotary encoder 138.
　制御装置１１７の角度差分算出部１２１は、目標値算出部１１４により算出された目標角度から微分器１４５により算出されたテーブル１３５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部１２２は、角度差分算出部１２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部１２３は、角度フィードバックゲイン乗算部１２２により算出された回転速度量から微分器１４５により算出されるテーブル１３５の回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部１２４は、回転速度差分算出部１２３により算出された回転速度差分に定数である速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部１２５は、速度フィードバックゲイン乗算部１２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部１２６は、速度フィードバックゲイン乗算部１２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部１２７は、比例制御部１２５により算出された比例操作量に積分制御部１２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 121 of the control device 117 calculates the angle difference by subtracting the angle of the table 135 calculated by the differentiator 145 from the target angle calculated by the target value calculation unit 114. The angle feedback gain multiplication unit 122 multiplies the angle difference calculated by the angle difference calculation unit 121 by a constant angle feedback gain to calculate the rotation speed amount. The rotation speed difference calculation unit 123 calculates the rotation speed difference by subtracting the rotation speed of the table 135 calculated by the differentiator 145 from the rotation speed amount calculated by the angle feedback gain multiplication unit 122. The speed feedback gain multiplication unit 124 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 123 by a constant speed feedback gain. The proportional control unit 125 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 124 by a constant proportional feedback gain. The integral control unit 126 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 124, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the integral operation amount. Is calculated. The adding unit 127 calculates an operation amount by multiplying the proportional operation amount calculated by the proportional control unit 125 by the integral operation amount calculated by the integration control unit 126.
　ダイレクトドライブモータ１３７は、加算部１２７により算出された操作量に基づいてテーブル１３５を回転させる。工作機械１３１は、このような動作により、その数値制御データに示されるようにカッター１３６がワーク１３９の縁を切削し、ワーク１３９の縁に歯を形成することによりワーク１３９を歯車に形成する。 The direct drive motor 137 rotates the table 135 based on the operation amount calculated by the adding unit 127. With such an operation, the machine tool 131 forms the workpiece 139 into a gear by the cutter 136 cutting the edge of the workpiece 139 and forming teeth on the edge of the workpiece 139 as indicated by the numerical control data.
　これらのような工作機械は、フィードバック制御系の定数を調整することで、たとえば、速度フィードバックのゲインを高くすることでワークに作用する外力に対するテーブル回転方向の剛性が確保することができる。しかし、ゲインを高く設定すると、制御系を起因とする振動現象が発生する。このため、これらのような工作機械は、対象とする全てのワークを加工する際に制御系を起因とする振動現象が発生しないように定数をセットし、全ての制御定数は出荷時に固定されている。工作機械は、ワークに作用する外力に対してテーブルの回転方向の剛性を確保し、かつ、発振現象を防止することが望まれている。 Such machine tools can secure the rigidity in the table rotation direction against an external force acting on the workpiece by adjusting the constant of the feedback control system, for example, by increasing the gain of the speed feedback. However, when the gain is set high, a vibration phenomenon caused by the control system occurs. For this reason, machine tools such as these set constants so that vibration phenomena caused by the control system do not occur when machining all target workpieces, and all control constants are fixed at the time of shipment. Yes. A machine tool is desired to ensure the rigidity in the rotational direction of the table against an external force acting on the workpiece and to prevent an oscillation phenomenon.
　特許第２９６９６４３号公報には、被加工歯車の加工完了時点を的確に検出して加工を終了することにより、加工能率を高めた歯車加工装置が開示されている。その歯車加工装置は、カッター歯車と被加工歯車をそれぞれ駆動するモータと、前記それぞれのモータの回転を検出するエンコーダと、これらモータをそれぞれ同期して回転するように制御するＰＬＬ制御手段と、カッター歯車による被加工歯車に対する加工量に応じて前記両モータの回転位相を逐次シフトさせるシフト手段と、加工部における振動を検出する手段とを備え、前記振動を検出する手段は、前記ＰＬＬ制御手段において前記それぞれのモータに与える指令基準パルスに対する前記エンコーダからの入力パルスの位相振れ状態を検出するジッタ量検出手段であることを特徴とする。 Japanese Patent No. 2996943 discloses a gear machining apparatus that increases machining efficiency by accurately detecting the completion of machining of a gear to be machined and ending the machining. The gear machining apparatus includes a motor for driving a cutter gear and a gear to be machined, an encoder for detecting rotation of each of the motors, PLL control means for controlling the motors to rotate in synchronization with each other, a cutter The PLL control unit includes a shift unit that sequentially shifts the rotational phases of the two motors according to a processing amount of the gear to be processed by the gear, and a unit that detects vibration in the processing unit. It is a jitter amount detecting means for detecting a phase fluctuation state of an input pulse from the encoder with respect to a command reference pulse given to each of the motors.
　特開平０７－８８７４６号公報には、簡易な装置で既存の機械に対しても簡単な改造で、検出を行うことにより切削中の異常（例えば工具切り刃摩耗の増加や破損など）をインプロセスで計測し、工具や機械の損傷と加工物の不良を防止する歯車加工機械における切削異常検出と非常戻し方法が開示されている。その歯車加工機械における切削異常検出と非常戻し方法は、工具と被加工歯車材を一定の回転比率で回転させながら切削加工を行う歯車加工機において、前記工具の駆動軸に回転周波数検出用の歯車と磁電式あるいは光電式検出器を設け、前記工具駆動軸の回転周波数変動を測定することにより、正常切削時の回転周波数と比較判定し切削状態の異常を検出することを特徴とする。 Japanese Patent Application Laid-Open No. 07-88746 discloses in-process abnormalities during cutting (for example, increased wear or damage to the cutting edge of the tool) by detecting the machine with a simple device and with simple modifications. A cutting abnormality detection and emergency return method is disclosed in a gear processing machine, which measures the damage of the tool and machine and prevents the defect of the workpiece. The cutting abnormality detection and emergency return method in the gear processing machine is a gear processing machine that performs cutting while rotating a tool and a gear material to be processed at a constant rotation ratio. And a magnetoelectric or photoelectric detector, and by measuring fluctuations in the rotational frequency of the tool drive shaft, it is compared with the rotational frequency during normal cutting to detect abnormalities in the cutting state.
特許第２９６９６４３号公報Japanese Patent No. 2969643 特開平０７－８８７４６号公報JP 07-88746 A
　本発明の課題は、ワークに作用する外力に対してテーブルの回転方向の剛性を確保し、かつ、発振現象を防止する工作機械および加工方法を提供することにある。 SUMMARY OF THE INVENTION An object of the present invention is to provide a machine tool and a machining method that ensure rigidity in the rotation direction of a table against an external force acting on a workpiece and prevent an oscillation phenomenon.
　本発明による工作機械は、速度フィードバックゲインを自動的に更新する速度フィードバックゲイン自動設定装置と、ワークを支持するテーブルの回転に関するセンサ値を計測するセンサと、そのテーブルの角度が目標角度に一致するように、その速度フィードバックゲインに基づいて、そのテーブルを回転させるモータをそのセンサ値に基づいてフィードバック制御する制御装置とを備えている。このような工作機械は、その速度フィードバックゲインが可変であり、その速度フィードバックゲインに適正な値が代入されたときに、そのワークに作用する外力に対してそのテーブルの回転方向の剛性を確保し、かつ、発振現象を防止することができる。 A machine tool according to the present invention includes a speed feedback gain automatic setting device that automatically updates a speed feedback gain, a sensor that measures a sensor value related to rotation of a table that supports a workpiece, and the angle of the table matches a target angle. As described above, a control device that feedback-controls a motor that rotates the table based on the sensor value based on the speed feedback gain. Such a machine tool has a variable speed feedback gain, and when the appropriate value is substituted for the speed feedback gain, it ensures the rigidity in the rotational direction of the table against the external force acting on the workpiece. In addition, the oscillation phenomenon can be prevented.
　その速度フィードバックゲイン自動設定装置は、そのセンサ値に基づいて振動の程度を算出する振動計測部と、その振動の程度に基づいてその速度フィードバックゲインを算出する速度フィードバックゲイン算出部とを備えていることが好ましい。 The speed feedback gain automatic setting device includes a vibration measuring unit that calculates the degree of vibration based on the sensor value, and a speed feedback gain calculating unit that calculates the speed feedback gain based on the degree of vibration. It is preferable.
　その速度フィードバックゲインは、その振動の程度が所定の閾値より大きいときに増加することが好ましい。 The speed feedback gain is preferably increased when the degree of vibration is greater than a predetermined threshold.
　そのセンサは、そのテーブルの角度を計測するロータリーエンコーダを含んでいることが好ましい。このとき、センサ値は、そのテーブルの角度を示している。 The sensor preferably includes a rotary encoder that measures the angle of the table. At this time, the sensor value indicates the angle of the table.
　本発明による工作機械は、そのワークに歯車に形成するための数値制御データに基づいてその目標角度を算出する目標値算出部をさらに備えている。すなわち、このような工作機械は、歯車を作成する歯車加工機に好適である。 The machine tool according to the present invention further includes a target value calculation unit that calculates a target angle based on numerical control data for forming a gear on the workpiece. That is, such a machine tool is suitable for a gear processing machine that creates gears.
　その速度フィードバックゲイン自動設定装置は、そのワークの材種を収集するワーク材種収集部と、複数材種と複数速度フィードバックゲインとを対応付けるテーブルを参照して、その複数速度フィードバックゲインのうちからその材種に対応するその速度フィードバックゲインを算出する速度フィードバックゲイン算出部とをさらに備えている。 The speed feedback gain automatic setting device refers to a workpiece material type collection unit that collects the material type of the workpiece, and a table that associates a plurality of material types with a plurality of speed feedback gains, and determines the speed feedback gain from the plurality of speed feedback gains. And a speed feedback gain calculating unit that calculates the speed feedback gain corresponding to the material type.
　そのワーク材種収集部は、そのワークを加工するためのデータからその材種を抽出する。 The workpiece material type collection unit extracts the material type from the data for processing the workpiece.
　本発明による加工方法は、速度フィードバックゲインを自動的に更新するステップと、ワークを支持するテーブルの回転に関するセンサ値を計測するステップと、そのテーブルの角度が目標角度に一致するように、その速度フィードバックゲインに基づいて、そのテーブルを回転させるモータをセンサ値に基づいてフィードバック制御するステップとを備えている。このような加工方法は、その速度フィードバックゲインが可変であり、その速度フィードバックゲインに適正な値が代入されたときに、そのワークに作用する外力に対してそのテーブルの回転方向の剛性を確保し、かつ、発振現象を防止することができる。 The machining method according to the present invention includes a step of automatically updating a speed feedback gain, a step of measuring a sensor value related to rotation of a table supporting a workpiece, and a speed of the table so that the angle of the table matches a target angle. Feedback control of a motor for rotating the table based on the feedback gain based on the sensor value. In such a machining method, the speed feedback gain is variable, and when an appropriate value is substituted for the speed feedback gain, the rigidity in the rotational direction of the table is secured against the external force acting on the workpiece. In addition, the oscillation phenomenon can be prevented.
　本発明による加工方法は、そのセンサ値に基づいて振動の程度を算出するステップと、その振動の程度に基づいてその速度フィードバックゲインを算出するステップとをさらに備えていることが好ましい。 Preferably, the processing method according to the present invention further includes a step of calculating the degree of vibration based on the sensor value and a step of calculating the speed feedback gain based on the degree of vibration.
　その速度フィードバックゲインは、その振動の程度が所定の閾値より大きいときに増加することが好ましい。 The speed feedback gain is preferably increased when the degree of vibration is greater than a predetermined threshold.
　そのセンサは、そのテーブルの角度を計測するロータリーエンコーダを含んでいることが好ましい。このとき、そのセンサ値は、そのテーブルの角度を示している。 The sensor preferably includes a rotary encoder that measures the angle of the table. At this time, the sensor value indicates the angle of the table.
　本発明による加工方法は、そのワークに歯車に形成するための数値制御データに基づいてその目標角度を算出するステップをさらに備えている。すなわち、このような工作機械は、歯車を作成する歯車加工機に好適である。 The machining method according to the present invention further includes a step of calculating the target angle based on numerical control data for forming a gear on the workpiece. That is, such a machine tool is suitable for a gear processing machine that creates gears.
　本発明による加工方法は、そのワークの材種を収集するステップと、複数材種と複数速度フィードバックゲインとを対応付けるテーブルを参照して、その複数速度フィードバックゲインのうちからその材種に対応するその速度フィードバックゲインを算出するステップとをさらに備えていることが好ましい。 The machining method according to the present invention refers to a step of collecting the material type of the workpiece and a table associating a plurality of material types and a plurality of speed feedback gains, and corresponding to the material type out of the plurality of speed feedback gains. Preferably, the method further comprises a step of calculating a speed feedback gain.
　本発明による加工方法は、そのワークを加工するためのデータからその材種を抽出するステップをさらに備えていることが好ましい。 The machining method according to the present invention preferably further includes a step of extracting the material type from data for machining the workpiece.
　本発明による工作機械および加工方法は、ワークに作用する外力に対してテーブルの回転方向の剛性を確保し、かつ、発振現象を防止することができる。 The machine tool and the machining method according to the present invention can ensure the rigidity in the rotation direction of the table against an external force acting on the workpiece and can prevent an oscillation phenomenon.
図１は、公知の工作機械を示すブロック図である。FIG. 1 is a block diagram showing a known machine tool. 図２は、公知の他の工作機械を示すブロック図である。FIG. 2 is a block diagram showing another known machine tool. 図３は、本発明による工作機械の実施の形態を示すブロック図である。FIG. 3 is a block diagram showing an embodiment of a machine tool according to the present invention. 図４は、様々な速度フィードバックゲインを用いてモータをフィードバック制御するときにテーブルが回転するときの剛性（コンプライアンス）の変化を示すグラフである。FIG. 4 is a graph showing changes in rigidity (compliance) when the table rotates when feedback controlling the motor using various speed feedback gains. 図５は、本発明による工作機械の実施の他の形態を示すブロック図である。FIG. 5 is a block diagram showing another embodiment of the machine tool according to the present invention. 図６は、本発明による工作機械の実施の他の形態を示すブロック図である。FIG. 6 is a block diagram showing another embodiment of the machine tool according to the present invention.
　図面を参照して、本発明による工作機械の実施の形態を記載する。その工作機械１は、図３に示されているように、工作機械本体２と工作機械制御装置３とを備えている。工作機械本体２は、テーブル５とカッター６とモータ７とウォームギア８とロータリーエンコーダ９とエンコーダ１０とを備えている。 Embodiments of a machine tool according to the present invention will be described with reference to the drawings. The machine tool 1 includes a machine tool body 2 and a machine tool control device 3 as shown in FIG. The machine tool main body 2 includes a table 5, a cutter 6, a motor 7, a worm gear 8, a rotary encoder 9, and an encoder 10.
　テーブル５は、鉛直方向に平行である回転軸を中心に回転可能に土台に支持されている。テーブル５は、その回転軸に垂直である支持面を有し、その支持面に接触するワーク１１を支持する。ワーク１１は、概ね円盤状に形成されている。カッター６は、図示されていない数値制御装置により制御されて回転することによりワーク１１の縁を切削し、ワーク１１の縁に歯を形成することによりワーク１１を歯車に形成する。モータ７は、回転可能に支持されるシャフトを備え、工作機械制御装置３から出力される操作量に基づいてそのシャフトを回転させる。ウォームギア８は、モータ７のシャフトの回転動力をテーブル５に伝達し、テーブル５を回転させる。ロータリーエンコーダ９は、テーブル５の角度を計測し、その角度を工作機械制御装置３に出力する。エンコーダ１０は、モータ７のシャフトの回転速度を計測し、その回転速度を工作機械制御装置３に出力する。 The table 5 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction. The table 5 has a support surface that is perpendicular to the rotation axis thereof, and supports the workpiece 11 that contacts the support surface. The workpiece 11 is generally formed in a disc shape. The cutter 6 is controlled and rotated by a numerical control device (not shown) to cut the edge of the workpiece 11 and form teeth on the edge of the workpiece 11 to form the workpiece 11 into a gear. The motor 7 includes a shaft that is rotatably supported, and rotates the shaft based on an operation amount output from the machine tool control device 3. The worm gear 8 transmits the rotational power of the shaft of the motor 7 to the table 5 and rotates the table 5. The rotary encoder 9 measures the angle of the table 5 and outputs the angle to the machine tool control device 3. The encoder 10 measures the rotational speed of the shaft of the motor 7 and outputs the rotational speed to the machine tool control device 3.
　工作機械制御装置３は、目標値算出部１４と積分器１５と速度フィードバックゲイン設定装置１６と制御装置１７とを備えている。目標値算出部１４は、ワーク１１を歯車に加工するための数値制御データとカッター６の動作とを収集し、その数値制御データと動作とに基づいて目標角度を算出する。積分器１５は、エンコーダ１０により計測されるモータ７のシャフトの回転速度を積分することにより、テーブル５の角度を算出する。 The machine tool control device 3 includes a target value calculation unit 14, an integrator 15, a speed feedback gain setting device 16, and a control device 17. The target value calculation unit 14 collects numerical control data for processing the workpiece 11 into a gear and the operation of the cutter 6 and calculates a target angle based on the numerical control data and the operation. The integrator 15 calculates the angle of the table 5 by integrating the rotational speed of the shaft of the motor 7 measured by the encoder 10.
　速度フィードバックゲイン設定装置１６は、ロータリーエンコーダ９により計測されるテーブル５の角度に基づいて速度フィードバックゲインを更新する。すなわち、速度フィードバックゲイン設定装置１６は、振動計測部２８と速度フィードバックゲイン算出部２９とを備えている。振動計測部２８は、ロータリーエンコーダ９により計測されるテーブル５の角度に基づいて、テーブル５の振動の程度を算出する。速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度に基づいて速度フィードバックゲインを算出する。 The speed feedback gain setting device 16 updates the speed feedback gain based on the angle of the table 5 measured by the rotary encoder 9. That is, the speed feedback gain setting device 16 includes a vibration measuring unit 28 and a speed feedback gain calculating unit 29. The vibration measuring unit 28 calculates the degree of vibration of the table 5 based on the angle of the table 5 measured by the rotary encoder 9. The speed feedback gain calculation unit 29 calculates a speed feedback gain based on the degree of vibration calculated by the vibration measurement unit 28.
　速度フィードバックゲイン算出部２９は、詳細には、閾値と複数の速度フィードバックゲインとを記録する記憶装置を備えている。速度フィードバックゲイン算出部２９は、初期的には、その複数の速度フィードバックゲインのうちの最小の速度フィードバックゲインを出力する。速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度がその閾値を越えたときに、その複数の速度フィードバックゲインのうちの現在出力している速度フィードバックゲインより１段階だけ大きい速度フィードバックゲインを出力する。すなわち、速度フィードバックゲイン設定装置１６は、その複数の速度フィードバックゲインのいずれかのみを出力し、速度フィードバックゲイン設定装置１６により出力される速度フィードバックゲインは、上限値と下限値とを有している。速度フィードバックゲイン算出部２９は、さらに、振動計測部２８により算出される振動の程度がその閾値を越え、かつ、その複数の速度フィードバックゲインが現在出力している速度フィードバックゲインより大きい速度フィードバックゲインを含んでいないときに、異常と判断して、工作機械本体２を停止させる。 Specifically, the speed feedback gain calculation unit 29 includes a storage device that records a threshold value and a plurality of speed feedback gains. The speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among the plurality of speed feedback gains. The speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold. Output speed feedback gain. That is, the speed feedback gain setting device 16 outputs only one of the plurality of speed feedback gains, and the speed feedback gain output by the speed feedback gain setting device 16 has an upper limit value and a lower limit value. . The speed feedback gain calculation unit 29 further selects a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value. When not included, it is determined as abnormal and the machine tool body 2 is stopped.
　制御装置１７は、目標値算出部１４により算出された目標角度と積分器１５により算出されたテーブル５の角度とエンコーダ１０により計測されるモータ７のシャフトの回転速度と速度フィードバックゲイン設定装置１６により設定される速度フィードバックゲインとに基づいて、テーブル５の角度が目標値算出部１４により算出された目標角度に一致するように、モータ７をフィードバック制御する。 The control device 17 uses the target angle calculated by the target value calculation unit 14, the angle of the table 5 calculated by the integrator 15, the rotational speed of the shaft of the motor 7 measured by the encoder 10, and the speed feedback gain setting device 16. Based on the set speed feedback gain, the motor 7 is feedback-controlled so that the angle of the table 5 matches the target angle calculated by the target value calculation unit 14.
　すなわち、制御装置１７は、角度差分算出部２１と角度フィードバックゲイン乗算部２２と回転速度差分算出部２３と速度フィードバックゲイン乗算部２４と比例制御部２５と積分制御部２６と加算部２７とを備えている。 That is, the control device 17 includes an angle difference calculation unit 21, an angle feedback gain multiplication unit 22, a rotation speed difference calculation unit 23, a speed feedback gain multiplication unit 24, a proportional control unit 25, an integration control unit 26, and an addition unit 27. ing.
　角度差分算出部２１は、目標値算出部１４により算出された目標角度から積分器１５により算出されたテーブル５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部２２は、角度差分算出部２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部２３は、角度フィードバックゲイン乗算部２２により算出された回転速度量からエンコーダ１０により計測されるモータ７のシャフトの回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部２４は、回転速度差分算出部２３により算出された回転速度差分に速度フィードバックゲイン設定装置１６により設定される速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部２５は、速度フィードバックゲイン乗算部２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部２６は、速度フィードバックゲイン乗算部２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部２７は、比例制御部２５により算出された比例操作量に積分制御部２６により算出された積分操作量を乗算することにより操作量を算出する。その操作量は、制御装置１７により出力される操作量に一致している。 The angle difference calculation unit 21 calculates the angle difference by subtracting the angle of the table 5 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14. The angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant. The rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 7 measured by the encoder 10 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22. The speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16. The proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain. The integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated. The adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26. The amount of operation matches the amount of operation output by the control device 17.
　本発明による加工方法の実施の形態は、工作機械１を用いて実行される。作業者は、まず、ワーク１１をテーブル５に設置し、図示されていない数値制御装置にワーク１１を歯車に加工するための数値制御データを入力する。その数値制御装置は、その数値制御データを工作機械制御装置３に出力し、その数値制御データに基づいてカッター６を回転させる。工作機械制御装置３の目標値算出部１４は、その数値制御データとカッター６の動作とを収集し、その数値制御データと動作とに基づいて目標角度を算出する。工作機械制御装置３の積分器１５は、エンコーダ１０により計測されるモータ７のシャフトの回転速度に基づいてテーブル５の角度を算出する。 The embodiment of the machining method according to the present invention is executed using the machine tool 1. First, the worker places the workpiece 11 on the table 5 and inputs numerical control data for processing the workpiece 11 into a gear into a numerical control device (not shown). The numerical control device outputs the numerical control data to the machine tool control device 3, and rotates the cutter 6 based on the numerical control data. The target value calculation unit 14 of the machine tool control device 3 collects the numerical control data and the operation of the cutter 6 and calculates a target angle based on the numerical control data and the operation. The integrator 15 of the machine tool control device 3 calculates the angle of the table 5 based on the rotational speed of the shaft of the motor 7 measured by the encoder 10.
　速度フィードバックゲイン設定装置１６の振動計測部２８は、ロータリーエンコーダ９により計測されるテーブル５の角度に基づいてテーブル５の振動の程度を算出する。速度フィードバックゲイン算出部２９は、記憶装置に予め記録されている複数の速度フィードバックゲインのうちの最小の速度フィードバックゲインを初期的に出力する。速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度がその閾値を越えたときに、その複数の速度フィードバックゲインのうちの現在出力している速度フィードバックゲインより１段階だけ大きい速度フィードバックゲインを出力する。 The vibration measuring unit 28 of the speed feedback gain setting device 16 calculates the degree of vibration of the table 5 based on the angle of the table 5 measured by the rotary encoder 9. The speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among a plurality of speed feedback gains recorded in advance in the storage device. The speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold. Output speed feedback gain.
　制御装置１７の角度差分算出部２１は、目標値算出部１４により算出された目標角度から積分器１５により算出されたテーブル５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部２２は、角度差分算出部２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部２３は、角度フィードバックゲイン乗算部２２により算出された回転速度量からエンコーダ１０により計測されるモータ７のシャフトの回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部２４は、回転速度差分算出部２３により算出された回転速度差分に速度フィードバックゲイン設定装置１６により設定される速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部２５は、速度フィードバックゲイン乗算部２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部２６は、速度フィードバックゲイン乗算部２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部２７は、比例制御部２５により算出された比例操作量に積分制御部２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 21 of the control device 17 calculates the angle difference by subtracting the angle of the table 5 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14. The angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant. The rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 7 measured by the encoder 10 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22. The speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16. The proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain. The integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated. The adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
　モータ７は、加算部２７により算出された操作量に基づいてシャフトを回転させる。ウォームギア８は、モータ７のシャフトの回転動力をテーブル５に伝達し、テーブル５を回転させる。工作機械１は、このような動作により、その数値制御データに示されるようにカッター６がワーク１１の縁を切削し、ワーク１１の縁に歯を形成することによりワーク１１を歯車に形成する。 The motor 7 rotates the shaft based on the operation amount calculated by the adding unit 27. The worm gear 8 transmits the rotational power of the shaft of the motor 7 to the table 5 and rotates the table 5. With this operation, the machine tool 1 forms the workpiece 11 into a gear by the cutter 6 cutting the edge of the workpiece 11 and forming teeth on the edge of the workpiece 11 as shown in the numerical control data.
　さらに、速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度がその閾値を越え、かつ、その複数の速度フィードバックゲインが現在出力している速度フィードバックゲインより大きい速度フィードバックゲインを含んでいないときに、異常と判断して、カッター６の回転とテーブル５の回転とを停止させる。このような停止によれば、工作機械制御装置３は、テーブル駆動系が発振現象を起こし制御不能に陥ることを防止することができる。 Furthermore, the speed feedback gain calculation unit 29 has a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output, and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value. When not included, it is determined as abnormal, and the rotation of the cutter 6 and the rotation of the table 5 are stopped. According to such a stop, the machine tool control device 3 can prevent the table drive system from causing an oscillation phenomenon and becoming uncontrollable.
　図４は、複数の速度フィードバックゲインを用いてモータ７をフィードバック制御するときにテーブル５が回転するときの剛性（コンプライアンス）の変化を示している。その変化３１は、ある値を示す速度フィードバックゲインを用いてモータ７をフィードバック制御するときのテーブル５の回転に関する剛性を示している。その変化３２は、変化３１の剛性を示すときの速度フィードバックゲインより大きい速度フィードバックゲインを用いてモータ７をフィードバック制御するときのテーブル５の回転に関する剛性を示している。その変化３３は、変化３２の剛性を示すときの速度フィードバックゲインより大きい速度フィードバックゲインを用いてモータ７をフィードバック制御するときのテーブル５の回転に関する剛性を示している。その変化３４は、変化３３の剛性を示すときの速度フィードバックゲインより大きい速度フィードバックゲインを用いてモータ７をフィードバック制御するときのテーブル５の回転に関する剛性を示している。その変化３５は、変化３４の剛性を示すときの速度フィードバックゲインより大きい速度フィードバックゲインを用いてモータ７をフィードバック制御するときのテーブル５の回転に関する剛性を示している。 FIG. 4 shows a change in rigidity (compliance) when the table 5 rotates when the motor 7 is feedback-controlled using a plurality of speed feedback gains. The change 31 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain indicating a certain value. The change 32 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 31 is indicated. The change 33 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 32 is indicated. The change 34 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 33 is indicated. The change 35 indicates the rigidity related to the rotation of the table 5 when the motor 7 is feedback-controlled using a speed feedback gain larger than the speed feedback gain when the rigidity of the change 34 is indicated.
　変化３１～変化３５は、フィードバック制御に用いられる速度フィードバックゲインがある値であるときに、外乱の周波数に対して変化することを示している。変化３１～変化３５は、さらに、速度フィードバックゲインを大きくしたときにテーブル５が回転するときの剛性が大きくなることを示し、テーブル５の回転が外乱に対して影響されにくくなることを示している。 Changes 31 to 35 indicate that the velocity feedback gain used for feedback control changes with respect to the frequency of the disturbance when the value is a certain value. The changes 31 to 35 further indicate that the rigidity when the table 5 rotates when the speed feedback gain is increased, and that the rotation of the table 5 is less affected by disturbance. .
　すなわち、工作機械１は、このような動作を実行することにより、歯車加工中に発生するワーク１１の振動が閾値内に収まるまで、制御定数（速度フィードバックゲイン）を自動調整することができる。このため、工作機械１は、ワーク１１に作用する外力に対するテーブル５の回転方向の剛性を確保することができ、かつ、制御系を起因とする発振現象を防止することができる。 That is, the machine tool 1 can automatically adjust the control constant (speed feedback gain) until the vibration of the workpiece 11 generated during gear machining falls within the threshold value by executing such an operation. For this reason, the machine tool 1 can ensure the rigidity of the rotation direction of the table 5 with respect to the external force acting on the workpiece 11, and can prevent an oscillation phenomenon caused by the control system.
　なお、振動計測部２８は、積分器１５により算出されるテーブル５の角度に基づいてテーブル５の振動の程度を算出する他の振動計測部に置換されることができる。このような工作機械は、既述の実施の形態における工作機械１と同様にして、ワーク１１に作用する外力に対するテーブル５の回転方向の剛性を確保することができ、かつ、制御系を起因とする発振現象を防止することができる。このような工作機械は、さらに、ロータリーエンコーダ９を省略することができ、より安価に作製されることができる。 The vibration measurement unit 28 can be replaced with another vibration measurement unit that calculates the degree of vibration of the table 5 based on the angle of the table 5 calculated by the integrator 15. Such a machine tool can ensure the rigidity in the rotation direction of the table 5 with respect to the external force acting on the workpiece 11 as well as the machine tool 1 in the above-described embodiment, and is caused by the control system. Oscillation phenomenon can be prevented. Such a machine tool can further omit the rotary encoder 9 and can be manufactured at a lower cost.
　なお、速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度に対応する速度フィードバックゲインを算出する他の速度フィードバックゲイン算出部に置換されることもできる。このような工作機械は、既述の実施の形態における工作機械１と同様にして、ワーク１１に作用する外力に対するテーブル５の回転方向の剛性を確保することができ、かつ、制御系を起因とする発振現象を防止することができる。 The speed feedback gain calculation unit 29 can be replaced with another speed feedback gain calculation unit that calculates a speed feedback gain corresponding to the degree of vibration calculated by the vibration measurement unit 28. Such a machine tool can ensure the rigidity in the rotation direction of the table 5 with respect to the external force acting on the workpiece 11 as well as the machine tool 1 in the above-described embodiment, and is caused by the control system. Oscillation phenomenon can be prevented.
　図５は、本発明による工作機械の実施の他の形態を示している。その工作機械４１は、工作機械本体４２と工作機械制御装置４３とを備えている。工作機械本体４２は、テーブル４５とカッター４６とダイレクトドライブモータ４７とロータリーエンコーダ４８とを備えている。 FIG. 5 shows another embodiment of the machine tool according to the present invention. The machine tool 41 includes a machine tool main body 42 and a machine tool control device 43. The machine tool main body 42 includes a table 45, a cutter 46, a direct drive motor 47, and a rotary encoder 48.
　テーブル４５は、鉛直方向に平行である回転軸を中心に回転可能に土台に支持されている。テーブル４５は、その回転軸に垂直である支持面を有し、その支持面に接触するワーク４９を支持する。ワーク４９は、概ね円盤状に形成されている。カッター４６は、ホブ型砥石から形成され、図示されていない数値制御装置により制御されて回転することによりワーク４９の縁を切削し、ワーク４９の縁に歯を形成することによりワーク４９を歯車に形成する。ダイレクトドライブモータ４７は、ダイレクトドライブモータロータ５１とダイレクトドライブモータステータ５２とを備えている。ダイレクトドライブモータロータ５１は、テーブル４５に固定されている。ダイレクトドライブモータステータ５２は、その土台に固定されている。ダイレクトドライブモータ４７は、工作機械制御装置４３から出力される操作量に基づいてテーブル４５を回転させる。ロータリーエンコーダ４８は、テーブル４５の角度を計測し、その角度を工作機械制御装置４３に出力する。 The table 45 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction. The table 45 has a support surface that is perpendicular to the rotation axis thereof, and supports a work 49 that contacts the support surface. The work 49 is formed in a generally disc shape. The cutter 46 is formed of a hob-type grindstone, and is rotated by being controlled by a numerical control device (not shown) to cut the edge of the workpiece 49, and by forming teeth on the edge of the workpiece 49, the workpiece 49 is turned into a gear. Form. The direct drive motor 47 includes a direct drive motor rotor 51 and a direct drive motor stator 52. The direct drive motor rotor 51 is fixed to the table 45. The direct drive motor stator 52 is fixed to the base. The direct drive motor 47 rotates the table 45 based on the operation amount output from the machine tool control device 43. The rotary encoder 48 measures the angle of the table 45 and outputs the angle to the machine tool control device 43.
　工作機械制御装置４３は、目標値算出部１４と微分器５５と速度フィードバックゲイン設定装置１６と制御装置１７とを備えている。目標値算出部１４は、ワーク４９を歯車に加工するための数値制御データとカッター４６の動作とを収集し、その数値制御データと動作とに基づいて目標角度を算出する。微分器５５は、ロータリーエンコーダ４８により計測されるテーブル４５の角度を微分することにより、テーブル４５の回転速度を算出する。 The machine tool control device 43 includes a target value calculation unit 14, a differentiator 55, a speed feedback gain setting device 16, and a control device 17. The target value calculation unit 14 collects numerical control data for processing the workpiece 49 into a gear and the operation of the cutter 46, and calculates a target angle based on the numerical control data and the operation. The differentiator 55 calculates the rotational speed of the table 45 by differentiating the angle of the table 45 measured by the rotary encoder 48.
　速度フィードバックゲイン設定装置１６は、振動計測部２８と速度フィードバックゲイン算出部２９とを備えている。振動計測部２８は、ロータリーエンコーダ４８により計測されるテーブル４５の角度に基づいて、テーブル４５の振動の程度を算出する。 The speed feedback gain setting device 16 includes a vibration measuring unit 28 and a speed feedback gain calculating unit 29. The vibration measuring unit 28 calculates the degree of vibration of the table 45 based on the angle of the table 45 measured by the rotary encoder 48.
　速度フィードバックゲイン算出部２９は、閾値と複数の速度フィードバックゲインとを記録する記憶装置を備えている。速度フィードバックゲイン算出部２９は、初期的には、その複数の速度フィードバックゲインのうちの最小の速度フィードバックゲインを出力する。速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度がその閾値を越えたときに、その複数の速度フィードバックゲインのうちの現在出力している速度フィードバックゲインより１段階だけ大きい速度フィードバックゲインを出力する。すなわち、速度フィードバックゲイン設定装置１６は、その複数の速度フィードバックゲインのいずれかのみを出力し、速度フィードバックゲイン設定装置１６により出力される速度フィードバックゲインは、上限値と下限値とを有している。速度フィードバックゲイン算出部２９は、さらに、振動計測部２８により算出される振動の程度がその閾値を越え、かつ、その複数の速度フィードバックゲインが現在出力している速度フィードバックゲインより大きい速度フィードバックゲインを含んでいないときに、異常と判断して、工作機械本体４２を停止させる。 The speed feedback gain calculation unit 29 includes a storage device that records a threshold value and a plurality of speed feedback gains. The speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among the plurality of speed feedback gains. The speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold. Output speed feedback gain. That is, the speed feedback gain setting device 16 outputs only one of the plurality of speed feedback gains, and the speed feedback gain output by the speed feedback gain setting device 16 has an upper limit value and a lower limit value. . The speed feedback gain calculation unit 29 further selects a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value. When not included, it is determined as abnormal and the machine tool main body 42 is stopped.
　制御装置１７は、角度差分算出部２１と角度フィードバックゲイン乗算部２２と回転速度差分算出部２３と速度フィードバックゲイン乗算部２４と比例制御部２５と積分制御部２６と加算部２７とを備えている。 The control device 17 includes an angle difference calculation unit 21, an angle feedback gain multiplication unit 22, a rotational speed difference calculation unit 23, a speed feedback gain multiplication unit 24, a proportional control unit 25, an integration control unit 26, and an addition unit 27. .
　角度差分算出部２１は、目標値算出部１４により算出された目標角度からロータリーエンコーダ４８により計測されるテーブル４５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部２２は、角度差分算出部２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部２３は、角度フィードバックゲイン乗算部２２により算出された回転速度量から微分器５５により算出されたテーブル４５の回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部２４は、回転速度差分算出部２３により算出された回転速度差分に速度フィードバックゲイン設定装置１６により設定される速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部２５は、速度フィードバックゲイン乗算部２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部２６は、速度フィードバックゲイン乗算部２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部２７は、比例制御部２５により算出された比例操作量に積分制御部２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 21 calculates the angle difference by subtracting the angle of the table 45 measured by the rotary encoder 48 from the target angle calculated by the target value calculation unit 14. The angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant. The rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the table 45 calculated by the differentiator 55 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22. The speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16. The proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain. The integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated. The adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
　本発明による加工方法の実施の形態は、工作機械４１を用いて実行される。作業者は、まず、ワーク４９をテーブル４５に設置し、図示されていない数値制御装置にワーク４９を歯車に加工するための数値制御データを入力する。その数値制御装置は、その数値制御データを工作機械制御装置４３に出力し、その数値制御データに基づいてカッター４６を回転させる。工作機械制御装置４３の目標値算出部１４は、数値制御データに基づいて目標角度を算出する。工作機械制御装置４３の微分器５５は、ロータリーエンコーダ４８により計測されたテーブル４５の回転角度に基づいてテーブル４５の回転速度を算出する。 The embodiment of the machining method according to the present invention is executed using the machine tool 41. First, the worker places the workpiece 49 on the table 45, and inputs numerical control data for processing the workpiece 49 into a gear into a numerical controller (not shown). The numerical control device outputs the numerical control data to the machine tool control device 43, and rotates the cutter 46 based on the numerical control data. The target value calculation unit 14 of the machine tool control device 43 calculates a target angle based on the numerical control data. The differentiator 55 of the machine tool control device 43 calculates the rotation speed of the table 45 based on the rotation angle of the table 45 measured by the rotary encoder 48.
　速度フィードバックゲイン設定装置１６の振動計測部２８は、ロータリーエンコーダ４８により計測されるテーブル４５の角度に基づいてテーブル４５の振動の程度を算出する。速度フィードバックゲイン算出部２９は、記憶装置に予め記録されている複数の速度フィードバックゲインのうちの最小の速度フィードバックゲインを初期的に出力する。速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度がその閾値を越えたときに、その複数の速度フィードバックゲインのうちの現在出力している速度フィードバックゲインより１段階だけ大きい速度フィードバックゲインを出力する。 The vibration measuring unit 28 of the speed feedback gain setting device 16 calculates the degree of vibration of the table 45 based on the angle of the table 45 measured by the rotary encoder 48. The speed feedback gain calculation unit 29 initially outputs the minimum speed feedback gain among a plurality of speed feedback gains recorded in advance in the storage device. The speed feedback gain calculating unit 29 is larger by one step than the currently output speed feedback gain among the plurality of speed feedback gains when the degree of vibration calculated by the vibration measuring unit 28 exceeds the threshold. Output speed feedback gain.
　制御装置１７の角度差分算出部２１は、目標値算出部１４により算出された目標角度から微分器５５により算出されたテーブル４５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部２２は、角度差分算出部２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部２３は、角度フィードバックゲイン乗算部２２により算出された回転速度量から微分器５５により算出されるテーブル４５の回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部２４は、回転速度差分算出部２３により算出された回転速度差分に速度フィードバックゲイン設定装置１６により設定される速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部２５は、速度フィードバックゲイン乗算部２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部２６は、速度フィードバックゲイン乗算部２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部２７は、比例制御部２５により算出された比例操作量に積分制御部２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 21 of the control device 17 calculates the angle difference by subtracting the angle of the table 45 calculated by the differentiator 55 from the target angle calculated by the target value calculation unit 14. The angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant. The rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the table 45 calculated by the differentiator 55 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22. The speed feedback gain multiplication unit 24 calculates a speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 16. The proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain. The integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated. The adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
　ダイレクトドライブモータ４７は、加算部２７により算出された操作量に基づいてテーブル４５を回転させる。工作機械４１は、このような動作により、その数値制御データに示されるようにカッター４６がワーク４９の縁を切削し、ワーク４９の縁に歯を形成することによりワーク４９を歯車に形成する。 The direct drive motor 47 rotates the table 45 based on the operation amount calculated by the adding unit 27. With this operation, the machine tool 41 forms the workpiece 49 into a gear by the cutter 46 cutting the edge of the workpiece 49 and forming teeth on the edge of the workpiece 49 as shown in the numerical control data.
　さらに、速度フィードバックゲイン算出部２９は、振動計測部２８により算出される振動の程度がその閾値を越え、かつ、その複数の速度フィードバックゲインが現在出力している速度フィードバックゲインより大きい速度フィードバックゲインを含んでいないときに、異常と判断して、カッター４６の回転とテーブル４５の回転とを停止させる。このような停止によれば、工作機械制御装置４３は、テーブル駆動系が発振現象を起こし制御不能に陥ることを防止することができる。 Furthermore, the speed feedback gain calculation unit 29 has a speed feedback gain that is greater than the speed feedback gain that the plurality of speed feedback gains are currently output, and the degree of vibration calculated by the vibration measurement unit 28 exceeds the threshold value. When not included, it is determined as abnormal, and the rotation of the cutter 46 and the rotation of the table 45 are stopped. According to such a stop, the machine tool control device 43 can prevent the table drive system from causing an oscillation phenomenon and becoming uncontrollable.
　すなわち、このような工作機械４１は、このような動作を実行することにより、既述の実施の形態における工作機械１と同様にして、ワーク４９に作用する外力に対するテーブル４５の回転方向の剛性を確保することができ、かつ、制御系を起因とする発振現象を防止することができる。すなわち、このような加工方法は、テーブル４５に直結してテーブル４５を回転させるダイレクトドライブモータ４７の制御にも適用されることができる。 That is, such a machine tool 41 performs such an operation, and in the same manner as the machine tool 1 in the above-described embodiment, provides the rigidity in the rotation direction of the table 45 with respect to the external force acting on the workpiece 49. The oscillation phenomenon caused by the control system can be prevented. That is, such a processing method can also be applied to control of the direct drive motor 47 that is directly connected to the table 45 and rotates the table 45.
　図６は、本発明による工作機械の実施のさらに他の形態を示している。その工作機械６１は、工作機械本体６２と工作機械制御装置６３とを備えている。工作機械本体６２は、テーブル６５とカッター６６とモータ６７とウォームギア６８とエンコーダ６９とを備えている。 FIG. 6 shows still another embodiment of the machine tool according to the present invention. The machine tool 61 includes a machine tool main body 62 and a machine tool control device 63. The machine tool main body 62 includes a table 65, a cutter 66, a motor 67, a worm gear 68, and an encoder 69.
　テーブル６５は、鉛直方向に平行である回転軸を中心に回転可能に土台に支持されている。テーブル６５は、その回転軸に垂直である支持面を有し、その支持面に接触するワーク７０を支持する。ワーク７０は、概ね円盤状に形成されている。カッター６６は、図示されていない数値制御装置により制御されて回転することによりワーク７０の縁を切削し、ワーク７０の縁に歯を形成することによりワーク７０を歯車に形成する。モータ６７は、回転可能に支持されるシャフトを備え、工作機械制御装置６３から出力される操作量に基づいてそのシャフトを回転させる。ウォームギア６８は、モータ６７のシャフトの回転動力をテーブル６５に伝達し、テーブル６５を回転させる。エンコーダ６９は、モータ６７のシャフトの回転速度を計測し、その回転速度を工作機械制御装置６３に出力する。 The table 65 is supported by a base so as to be rotatable about a rotation axis parallel to the vertical direction. The table 65 has a support surface that is perpendicular to the rotation axis thereof, and supports the work 70 that contacts the support surface. The workpiece 70 is generally formed in a disc shape. The cutter 66 is controlled and rotated by a numerical control device (not shown) to cut the edge of the work 70 and form teeth on the edge of the work 70 to form the work 70 into a gear. The motor 67 includes a shaft that is rotatably supported, and rotates the shaft based on an operation amount output from the machine tool control device 63. The worm gear 68 transmits the rotational power of the shaft of the motor 67 to the table 65 to rotate the table 65. The encoder 69 measures the rotational speed of the shaft of the motor 67 and outputs the rotational speed to the machine tool control device 63.
　工作機械制御装置６３は、目標値算出部１４と積分器１５と速度フィードバックゲイン設定装置７１と制御装置１７とを備えている。目標値算出部１４は、ワーク７０を歯車に加工するための数値制御データとカッター６６の動作とを収集し、その数値制御データと動作とに基づいて目標角度を算出する。積分器１５は、エンコーダ６９により計測されるモータ６７のシャフトの回転速度を積分することにより、テーブル６５の角度を算出する。 The machine tool control device 63 includes a target value calculation unit 14, an integrator 15, a speed feedback gain setting device 71, and a control device 17. The target value calculation unit 14 collects numerical control data for processing the workpiece 70 into a gear and the operation of the cutter 66, and calculates a target angle based on the numerical control data and the operation. The integrator 15 calculates the angle of the table 65 by integrating the rotational speed of the shaft of the motor 67 measured by the encoder 69.
　速度フィードバックゲイン設定装置７１は、その数値制御データに基づいて速度フィードバックゲインを算出する。すなわち、速度フィードバックゲイン設定装置７１は、ワーク材種収集部７２と速度フィードバックゲイン算出部７３とを備えている。ワーク材種収集部７２は、その数値制御データを解析して、その数値制御データからワーク７０の材種を抽出する。 The speed feedback gain setting device 71 calculates a speed feedback gain based on the numerical control data. That is, the speed feedback gain setting device 71 includes a workpiece material type collection unit 72 and a speed feedback gain calculation unit 73. The workpiece material type collecting unit 72 analyzes the numerical control data and extracts the material type of the workpiece 70 from the numerical control data.
　速度フィードバックゲイン算出部７３は、材種集合と速度フィードバックゲイン集合とを対応付けるテーブルを記録する記憶装置を備えている。すなわち、その材種集合のうちの任意の要素は、その速度フィードバックゲイン集合のうちの１つの要素に対応している。その材種集合の要素は、それぞれ、ワーク７０に適用される材料の材種を示している。その速度フィードバックゲイン集合の要素は、それぞれ、制御装置１７で用いられる速度フィードバックゲインの値を示している。速度フィードバックゲイン算出部７３は、そのテーブルを参照して、その速度フィードバックゲイン集合からワーク材種収集部７２により抽出される材種に対応する速度フィードバックゲインを算出する。 The speed feedback gain calculation unit 73 includes a storage device that records a table associating the material type set and the speed feedback gain set. That is, an arbitrary element in the grade set corresponds to one element in the speed feedback gain set. Each element of the material type set indicates the material type of the material applied to the workpiece 70. Each element of the speed feedback gain set indicates the value of the speed feedback gain used in the control device 17. The speed feedback gain calculation unit 73 refers to the table and calculates a speed feedback gain corresponding to the material type extracted by the workpiece material type collection unit 72 from the speed feedback gain set.
　制御装置１７は、角度差分算出部２１と角度フィードバックゲイン乗算部２２と回転速度差分算出部２３と速度フィードバックゲイン乗算部２４と比例制御部２５と積分制御部２６と加算部２７とを備えている。 The control device 17 includes an angle difference calculation unit 21, an angle feedback gain multiplication unit 22, a rotational speed difference calculation unit 23, a speed feedback gain multiplication unit 24, a proportional control unit 25, an integration control unit 26, and an addition unit 27. .
　角度差分算出部２１は、目標値算出部１４により算出された目標角度から積分器１５により算出されたテーブル６５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部２２は、角度差分算出部２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部２３は、角度フィードバックゲイン乗算部２２により算出された回転速度量からエンコーダ６９により計測されるモータ６７のシャフトの回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部２４は、回転速度差分算出部２３により算出された回転速度差分に速度フィードバックゲイン算出部７３により算出される速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部２５は、速度フィードバックゲイン乗算部２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部２６は、速度フィードバックゲイン乗算部２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部２７は、比例制御部２５により算出された比例操作量に積分制御部２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 21 calculates the angle difference by subtracting the angle of the table 65 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14. The angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant. The rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 67 measured by the encoder 69 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22. The speed feedback gain multiplication unit 24 multiplies the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain calculated by the speed feedback gain calculation unit 73 to calculate the speed operation amount. The proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain. The integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated. The adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
　本発明による加工方法の実施の形態は、工作機械６１を用いて実行される。作業者は、まず、ワーク７０をテーブル６５に設置し、図示されていない数値制御装置にワーク７０を歯車に加工するための数値制御データを入力する。その数値制御装置は、その数値制御データを工作機械制御装置６３に出力し、その数値制御データに基づいてカッター６６を回転させる。工作機械制御装置６３の目標値算出部１４は、その数値制御データとカッター６６の動作とを収集し、その数値制御データとカッター６６の動作とに基づいて目標角度を算出する。工作機械制御装置６３の積分器１５は、エンコーダ６９により計測されるモータ６７のシャフトの回転速度に基づいてテーブル６５の角度を算出する。 The embodiment of the machining method according to the present invention is executed using the machine tool 61. First, the operator places the work 70 on the table 65, and inputs numerical control data for processing the work 70 into a gear into a numerical control device (not shown). The numerical control device outputs the numerical control data to the machine tool control device 63, and rotates the cutter 66 based on the numerical control data. The target value calculation unit 14 of the machine tool control device 63 collects the numerical control data and the operation of the cutter 66 and calculates a target angle based on the numerical control data and the operation of the cutter 66. The integrator 15 of the machine tool control device 63 calculates the angle of the table 65 based on the rotational speed of the shaft of the motor 67 measured by the encoder 69.
　速度フィードバックゲイン設定装置７１のワーク材種収集部７２は、その数値制御データに基づいてワーク７０の材料の材種を算出する。速度フィードバックゲイン算出部７３は、速度フィードバックゲイン算出部７３は、材種集合と速度フィードバックゲイン集合とを対応付けるテーブルを参照して、その速度フィードバックゲイン集合からワーク材種収集部７２により抽出される材種に対応する速度フィードバックゲインを算出する。 The workpiece material type collection unit 72 of the speed feedback gain setting device 71 calculates the material type of the material of the workpiece 70 based on the numerical control data. The speed feedback gain calculation unit 73 refers to a table associating the material type set with the speed feedback gain set, and the material extracted from the speed feedback gain set by the work material type collection unit 72 is referred to by the speed feedback gain calculation unit 73. The speed feedback gain corresponding to the seed is calculated.
　制御装置１７の角度差分算出部２１は、目標値算出部１４により算出された目標角度から積分器１５により算出されたテーブル６５の角度を減算することにより角度差分を算出する。角度フィードバックゲイン乗算部２２は、角度差分算出部２１により算出された角度差分に定数である角度フィードバックゲインを乗算して回転速度量を算出する。回転速度差分算出部２３は、角度フィードバックゲイン乗算部２２により算出された回転速度量からエンコーダ６９により計測されるモータ６７のシャフトの回転速度を減算することにより回転速度差分を算出する。速度フィードバックゲイン乗算部２４は、回転速度差分算出部２３により算出された回転速度差分に速度フィードバックゲイン設定装置７１により設定される速度フィードバックゲインを乗算することにより速度操作量を算出する。比例制御部２５は、速度フィードバックゲイン乗算部２４により算出された速度操作量に定数である比例フィードバックゲインを乗算して比例操作量を算出する。積分制御部２６は、速度フィードバックゲイン乗算部２４により算出された速度操作量を積分することにより積分制御量を算出し、その積分制御量に定数である積分フィードバックゲインを乗算することにより積分操作量を算出する。加算部２７は、比例制御部２５により算出された比例操作量に積分制御部２６により算出された積分操作量を乗算することにより操作量を算出する。 The angle difference calculation unit 21 of the control device 17 calculates the angle difference by subtracting the angle of the table 65 calculated by the integrator 15 from the target angle calculated by the target value calculation unit 14. The angle feedback gain multiplication unit 22 calculates the rotation speed amount by multiplying the angle difference calculated by the angle difference calculation unit 21 by an angle feedback gain that is a constant. The rotation speed difference calculation unit 23 calculates the rotation speed difference by subtracting the rotation speed of the shaft of the motor 67 measured by the encoder 69 from the rotation speed amount calculated by the angle feedback gain multiplication unit 22. The speed feedback gain multiplication unit 24 calculates the speed operation amount by multiplying the rotation speed difference calculated by the rotation speed difference calculation unit 23 by the speed feedback gain set by the speed feedback gain setting device 71. The proportional control unit 25 calculates a proportional operation amount by multiplying the speed operation amount calculated by the speed feedback gain multiplication unit 24 by a constant proportional feedback gain. The integration control unit 26 calculates an integral control amount by integrating the speed operation amount calculated by the speed feedback gain multiplication unit 24, and multiplies the integral control amount by an integral feedback gain that is a constant, thereby integrating the operation amount. Is calculated. The adding unit 27 calculates the operation amount by multiplying the proportional operation amount calculated by the proportional control unit 25 by the integral operation amount calculated by the integration control unit 26.
　モータ６７は、加算部２７により算出された操作量に基づいてシャフトを回転させる。ウォームギア６８は、モータ６７のシャフトの回転動力をテーブル６５に伝達し、テーブル６５を回転させる。工作機械６１は、このような動作により、その数値制御データに示されるようにカッター６６がワーク７０の縁を切削し、ワーク７０の縁に歯を形成することによりワーク７０を歯車に形成する。 The motor 67 rotates the shaft based on the operation amount calculated by the adding unit 27. The worm gear 68 transmits the rotational power of the shaft of the motor 67 to the table 65 to rotate the table 65. With such an operation, the machine tool 61 forms the workpiece 70 into a gear by the cutter 66 cutting the edge of the workpiece 70 and forming teeth on the edge of the workpiece 70 as shown in the numerical control data.
　ワーク７０に作用する外力に対するテーブル６５の回転方向の剛性は、ワーク７０の切削性・研削性により変化する。その切削性・研削性は、ワーク７０を形成する材料の材種に固有である。このため、工作機械６１は、速度フィードバックゲイン算出部７３により記録されるテーブルを適切に作成することにより、速度フィードバックゲインをより適切に設定することができる。工作機械６１は、このように速度フィードバックゲインが適切に設定されたときに、ワーク７０に作用する外力に対するテーブル６５の回転方向の剛性を確保することができ、かつ、制御系を起因とする発振現象を防止することができる。 The rigidity in the rotational direction of the table 65 with respect to the external force acting on the work 70 varies depending on the machinability and grindability of the work 70. The machinability and grindability are specific to the material type of the material forming the workpiece 70. For this reason, the machine tool 61 can set the speed feedback gain more appropriately by appropriately creating the table recorded by the speed feedback gain calculator 73. When the speed feedback gain is appropriately set in this way, the machine tool 61 can ensure the rigidity in the rotational direction of the table 65 with respect to the external force acting on the workpiece 70, and oscillation caused by the control system The phenomenon can be prevented.
　なお、ワーク材種収集部７２は、工作機械制御装置６３が備える入力装置を介して入力される材種をその入力装置から収集する他のワーク材種収集部に置換されることができる。このような工作機械は、既述の実施の形態における工作機械６１と同様にして、速度フィードバックゲインをより適切に設定することができ、ワーク７０に作用する外力に対するテーブル６５の回転方向の剛性を確保することができ、かつ、制御系を起因とする発振現象を防止することができる。 The workpiece material type collecting unit 72 can be replaced with another workpiece material type collecting unit that collects the material type input via the input device included in the machine tool control device 63 from the input device. In such a machine tool, the speed feedback gain can be set more appropriately in the same manner as the machine tool 61 in the above-described embodiment, and the rigidity in the rotation direction of the table 65 with respect to the external force acting on the workpiece 70 can be increased. The oscillation phenomenon caused by the control system can be prevented.
　なお、速度フィードバックゲイン設定装置７１は、初期的に、ワーク７０の材種に基づいて速度フィードバックゲインを算出し、以降に、既述の実施の形態と同様にして、テーブル６５の振動に基づいて速度フィードバックゲインを算出することもできる。このような速度フィードバックゲインの算出においても、既述の実施の形態と同様にして、発振現象を防止することができる。 The speed feedback gain setting device 71 initially calculates the speed feedback gain based on the material type of the workpiece 70, and thereafter, based on the vibration of the table 65, as in the above-described embodiment. A speed feedback gain can also be calculated. Also in the calculation of the speed feedback gain, the oscillation phenomenon can be prevented in the same manner as in the above-described embodiment.

Claims (14)

  1. 　速度フィードバックゲインを自動的に更新する速度フィードバックゲイン自動設定装置と、
    　ワークを支持するテーブルの回転に関するセンサ値を計測するセンサと、
    　前記テーブルの角度が目標角度に一致するように、前記速度フィードバックゲインに基づいて、前記テーブルを回転させるモータを前記センサ値に基づいてフィードバック制御する制御装置
    　とを具備する工作機械。     A speed feedback gain automatic setting device that automatically updates the speed feedback gain;
    A sensor for measuring a sensor value related to rotation of the table supporting the workpiece;
    A control device that feedback-controls a motor that rotates the table based on the sensor value based on the speed feedback gain so that the angle of the table matches a target angle.
  2. 　請求項１において、
    　前記速度フィードバックゲイン自動設定装置は、
    　前記センサ値に基づいて振動の程度を算出する振動計測部と、
    　前記振動の程度に基づいて前記速度フィードバックゲインを算出する速度フィードバックゲイン算出部とを備える
    　工作機械。     In claim 1,
    The speed feedback gain automatic setting device is:
    A vibration measuring unit that calculates the degree of vibration based on the sensor value;
    A speed feedback gain calculating unit that calculates the speed feedback gain based on the degree of vibration.
  3. 　請求項２において、
    　前記速度フィードバックゲインは、前記振動の程度が所定の閾値より大きいときに増加する
    　工作機械。     In claim 2,
    The speed feedback gain increases when the degree of vibration is greater than a predetermined threshold.
  4. 　請求項３において、
    　前記センサは、前記テーブルの角度を計測するロータリーエンコーダを含み、
    　前記センサ値は、前記テーブルの角度を示す
    　工作機械。     In claim 3,
    The sensor includes a rotary encoder that measures an angle of the table,
    The sensor value indicates an angle of the table.
  5. 　請求項４において、
    　前記ワークに歯車に形成するための数値制御データに基づいて前記目標角度を算出する目標値算出部
    　をさらに具備する工作機械。     In claim 4,
    A machine tool further comprising a target value calculation unit that calculates the target angle based on numerical control data for forming a gear on the workpiece.
  6. 　請求項１において、
    　前記速度フィードバックゲイン自動設定装置は、
    　前記ワークの材種を収集するワーク材種収集部と、
    　複数材種と複数速度フィードバックゲインとを対応付けるテーブルを参照して、前記複数速度フィードバックゲインのうちから前記材種に対応する前記速度フィードバックゲインを算出する速度フィードバックゲイン算出部とをさらに備える
    　工作機械。     In claim 1,
    The speed feedback gain automatic setting device is:
    A workpiece material type collecting unit for collecting the material type of the workpiece;
    A machine tool further comprising: a speed feedback gain calculation unit that calculates a speed feedback gain corresponding to the material type from the plurality of speed feedback gains with reference to a table associating the plurality of material types with a plurality of speed feedback gains.
  7. 　請求項６において、
    　前記ワーク材種収集部は、前記ワークを加工するためのデータから前記材種を抽出する
    　工作機械。     In claim 6,
    The workpiece material type collection unit extracts the material type from data for processing the workpiece.
  8. 　速度フィードバックゲインを自動的に更新するステップと、
    　ワークを支持するテーブルの回転に関するセンサ値を計測するステップと、
    　前記テーブルの角度が目標角度に一致するように、前記速度フィードバックゲインに基づいて、前記テーブルを回転させるモータを前記センサ値に基づいてフィードバック制御するステップ
    　とを具備する加工方法。     Automatically updating the speed feedback gain;
    Measuring a sensor value related to rotation of the table supporting the workpiece;
    A step of feedback-controlling a motor for rotating the table based on the sensor value based on the speed feedback gain so that the angle of the table matches a target angle.
  9. 　請求項８において、
    　前記センサ値に基づいて振動の程度を算出するステップと、
    　前記振動の程度に基づいて前記速度フィードバックゲインを算出するステップ
    　とをさらに具備する加工方法。     In claim 8,
    Calculating the degree of vibration based on the sensor value;
    And a step of calculating the speed feedback gain based on the degree of vibration.
  10. 　請求項９において、
    　前記速度フィードバックゲインは、前記振動の程度が所定の閾値より大きいときに増加する
    　加工方法。     In claim 9,
    The speed feedback gain increases when the degree of vibration is greater than a predetermined threshold.
  11. 　請求項１０において、
    　前記センサは、前記テーブルの角度を計測するロータリーエンコーダを含み、
    　前記センサ値は、前記テーブルの角度を示す
    　加工方法。     In claim 10,
    The sensor includes a rotary encoder that measures an angle of the table,
    The sensor value indicates an angle of the table.
  12. 　請求項１１において、
    　前記ワークに歯車に形成するための数値制御データに基づいて前記目標角度を算出するステップ
    　をさらに具備する加工方法。     In claim 11,
    A machining method further comprising: calculating the target angle based on numerical control data for forming a gear on the workpiece.
  13. 　請求項８において、
    　前記ワークの材種を収集するステップと、
    　複数材種と複数速度フィードバックゲインとを対応付けるテーブルを参照して、前記複数速度フィードバックゲインのうちから前記材種に対応する前記速度フィードバックゲインを算出するステップ
    　とをさらに具備する加工方法。     In claim 8,
    Collecting a grade of the workpiece;
    And a step of calculating the speed feedback gain corresponding to the material type out of the plurality of speed feedback gains with reference to a table associating a plurality of material types with a plurality of speed feedback gains.
  14. 　請求項１３において、
    　前記ワークを加工するためのデータから前記材種を抽出するステップ
    　をさらに具備する加工方法。     In claim 13,
    The processing method further comprising the step of extracting the material type from data for processing the workpiece.
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