JP4913993B2 - Oscillating actuator device and laser processing device - Google Patents

Description

  The present invention provides a swing-type actuator device in which one of a permanent magnet or a coil is a stator and the other is a mover and is fixed to a rotating shaft, and the mover is swung within a predetermined angle range and such a swing. The present invention relates to a laser processing apparatus using a dynamic actuator device.

  In laser processing equipment that drills holes in the manufacturing process of printed wiring boards, a positioning control mechanism is required to irradiate laser beams one after another to multiple processing positions on the workpiece. High processing throughput and high-precision processing In order to realize the above, a galvano scanner device is often used. The galvano scanner device is a device in which a mirror (galvano mirror) is fixed to a rotation shaft of a swing type actuator device.

  The laser processing apparatus is usually a numerical control (NC) apparatus having a hierarchical control structure, and the galvano scanner apparatus is included in the lowest hierarchy. In a higher-level control device (hereinafter referred to as upper control), two-dimensional hole position coordinates are described in the NC program in the order in which the two-dimensional hole position coordinates are processed based on CAM (Computer Aided Manufacturing) data of the printed wiring board. When machining is started, the host control sequentially converts the hole position coordinates in the NC program, and transmits time-series angle command data to the galvano scanner device. In order to process the hole into a perfect circle, it is necessary to irradiate the laser beam after the mirror is stationary at an angle specified by the angle command data. For this reason, the transmission of the angle command data and the laser light irradiation control are performed in synchronization within the host control.

  Electromagnetic actuators are frequently used as the above-mentioned oscillating actuators. The electromagnetic actuator forms a magnetic field in the air gap between the permanent magnet of the stator and the yoke, and the moving coil generates a driving torque based on the Fleming's left hand principle and transmits it to the rotating shaft. There are a coil-type actuator and a moving magnet-type actuator in which a stator is a coil, a mover is a permanent magnet, and a driving torque resulting from the reaction of Fleming's left-hand rule is received by the permanent magnet and transmitted to the rotating shaft (Patent Document 1). ).

FIG. 5 is a sectional view of a magnetic circuit in a conventional four-pole moving coil actuator.

  The stator is composed of four permanent magnets 1 having a central angle of 90 degrees, an outer yoke 2 and an inner yoke 3. The permanent magnets 1 are arranged side by side so that N poles and S poles are alternated, and generally radial magnetic lines of force are generated in the air gap 4 between the permanent magnet 1 and the inner yoke 3. In the air gap 4, the conducting wire forming the movable coil 5 is arranged so that a couple is generated in a direction perpendicular to the paper surface. The movable coil 5 is fastened to the rotary shaft 6 by components not shown. When a current is supplied to the movable coil 5, the rotating shaft 6 is rotated by torque applied to the movable coil 5.

  Further, as a swing type actuator having the same operation principle as a moving coil type actuator, there is a voice coil motor used for positioning control of a magnetic head in a magnetic disk device (Patent Document 2). Similarly to a moving magnet actuator, a technique for reducing torque ripple is disclosed for a brushless motor using a permanent magnet as a rotor (Patent Document 3).

However, Patent Document 3 discloses a technique in which a magnetic material is disposed in a recess provided on the surface of a permanent magnet and the air gap length between the permanent magnet and the stator is different in order to reduce torque ripple of the brushless motor. Although disclosed, none of Patent Documents 1 to 3 discloses a technique for making the torque constant uniform.
JP 2003-107386 A JP-A-6-46555 JP 2000-166141 A

FIG. 6 is a diagram schematically showing the relationship between the swing angle of the rotary shaft and the torque constant in a conventional moving coil actuator, where the vertical axis is the torque constant [N · m / A] and the horizontal axis is the swing. The moving angle θ. The torque constant is the magnitude of drive torque generated when a current of 1 A is supplied to the coil. The maximum swing angle θmax of the swing angle is about 15 °.

  If the torque constant is constant in the entire swinging range (−θmax to + θmax) of the rotating shaft, the positioning time can be made constant by feedback control of the angle of the mirror fixed to the rotating shaft. However, as shown in the figure, the torque constant in the conventional moving coil actuator is high near the center of the swing range (θ = 0), and at both ends (maximum swing angles −θmax, + θmax). The profile decreased as the angle swung. The reason for such a profile is that the magnetic flux density of the air gap 4 becomes non-uniform depending on the angle. That is, near the center of each magnetic pole of the permanent magnet 1, the magnetic field lines are directed in the radial direction, and thus the magnetic flux density is high. It is.

  When the angle of the mirror (rotating shaft) is feedback controlled with the torque constant being not constant over the entire range of the swing angle (from -θmax to + θmax), the settling waveform fluctuates for each swing angle θ. The positioning time until convergence within the range is different. For this reason, if the processing accuracy is prioritized, the processing time becomes long, and if the processing efficiency is prioritized, the processing accuracy is lowered.

  If the torque constant is measured in advance for each swing angle θ and the fluctuation characteristic of the control system is suppressed by multiplying the inverse characteristic of the fluctuation by a coefficient to the control input signal, the characteristic fluctuation of the controlled object is reduced. The influence on the performance of the control system can be reduced (so-called robustness). However, since it is necessary to measure a torque constant variation for each actuator, it is difficult to improve workability.

  The present invention has been made in view of such a state of the art, and an object of the present invention is to provide an oscillating actuator device capable of making the torque constant substantially uniform and such an oscillating actuator device. It is to provide a laser processing machine.

To solve the above problems, the present invention is to fix a permanent magnet stator, the rotation axis coil as the movable element, the rocking actuator for swinging in a pre determined range of angles of said movable element, said coil Recesses are provided along the rotational axis direction at the end of one angular range in the circumferential direction at locations where the coils on the inner peripheral surface side of the permanent magnet face each other when positioned at both ends of the angular range. One place is formed , and a soft magnetic member is disposed in the recess.

  According to the present invention, since the torque constant within the swing angle range becomes substantially constant, the settling waveform becomes almost constant regardless of the value of the swing angle θ when feedback control is performed, thereby improving machining accuracy and machining efficiency. Can be made.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a sectional view of a moving coil type oscillating actuator device according to a first embodiment of the present invention. FIG. 2 is an XOY sectional view in FIG. A reference numeral is attached, and a duplicate description is omitted.

  As shown in FIG. 2, the rotating shaft 6 is supported by a stator (here, the outer yoke 2) via a pair of bearings 7 and a plate 70 that holds the bearings 7. The movable coil 5 is fixed to the rotating shaft 6 by torque transmitting parts 51 and 52. A rotary encoder disk 8 is attached to the end of the rotating shaft 6. The encoder head 9 is fixed to the case 71 so as to face the rotary encoder disk 8, and angle information is obtained from the rotary encoder disk 8. The case 71 is fixed to an end portion of a stator (here, the outer yoke 2).

  A portion of the inner surface of the permanent magnet 1 facing the movable coil 5 in the vicinity of the maximum swing angles + θmax and −θmax of the rotating shaft 6 includes first and second recesses 11 a, along the axis O direction of the rotating shaft 6. 11b is formed, and the soft magnetic plate 12 is disposed in the first and second recesses 11a and 11b. The soft magnetic plate 12 is embedded in the recesses 11a and 11b so that the size of the air gap 4 is substantially uniform in the circumferential direction.

  With this configuration, as shown in FIG. 1, the magnetic field lines exit from the N pole of the permanent magnet 1, pass through the air gap 4 and the inner yoke 3, enter the permanent magnet 1 at the S pole, and enter the outer yoke 2 from the back side. The closed loop returns to the original N pole. The soft magnetic plate 12 provided in the permanent magnet 1 functions to gather magnetic lines of force at the end of the permanent magnet 1.

  FIG. 3 is a diagram schematically showing the relationship between the swing angle of the rotating shaft and the torque constant in the swing type actuator according to the present embodiment. For comparison, the curves described in FIG. 7 are shown side by side.

  As shown in the figure, in the oscillating actuator device according to this embodiment, there is little drop in the vicinity of the maximum oscillating angles + θmax and −θmax of the rotating shaft 6 from the torque constant at the oscillating center (θ = 0). Therefore, the torque constant is substantially uniform in the variable range of the swing angle θ (−θmax ≦ θ ≦ + θmax). Therefore, when the swing angle θ of the rotating shaft 6 is measured by the encoder head 9 and feedback control is performed by a control circuit (not shown) based on the result, the settling waveform is substantially uniform regardless of the mirror position (angle). Therefore, the positioning time until convergence within a predetermined accuracy range becomes constant, and the processing accuracy and processing efficiency can be improved.

  1 and 2 can optimize the shape (dimension) using, for example, electromagnetic CAD software based on the finite element method.

  Moreover, an electromagnetic steel plate can be used as the soft magnetic plate 12, and as its physical properties, the saturation magnetic flux density is high in a pure iron system, and the relative permeability is almost maximized near the magnetic flux density at the operating point of the permanent magnet 1, In order to suppress eddy current, a material having a large electric resistance is desirable. In order to suppress eddy current, the soft magnetic plate 12 may be a laminated plate.

  In this embodiment, a moving coil type (movable coil type) actuator device is illustrated, but in a moving magnet type actuator that uses a coil as a stator and a permanent magnet as a mover and is fixed to a rotating shaft. Can be applied. That is, if recesses are provided near both ends of the movable range of the magnetic pole facing the air gap of the permanent magnet fixed to the rotating shaft, and a soft magnetic plate is fitted there, as in the above case, within the swing angle range. The torque constant can be made substantially uniform. In this case as well, the dimension (dimension) of the magnetic circuit can be optimized by a known electromagnetic CAD software.

  Other parts not specifically described are configured in the same manner as the conventional example described above and function in the same manner.

<Second Embodiment>
FIG. 4 is a diagram showing a configuration of a printed circuit board drilling laser machine to which the present invention is applied, and illustrations of portions not related to the essence of the invention are omitted.

  In the figure, a first galvano scanner 100a and a second galvano scanner 100b are obtained by fixing a mirror to the rotation shaft of the oscillating actuator according to the present invention. Specifically, the moving-coil swing actuator device described in the first and second embodiments is used.

  In the figure, a laser beam 30 output from a laser oscillator 310 is shaped through an optical beam processing system including a collimator 312 and an aperture 314 via a mirror 313a and a mirror 313b. The light enters the mirror of the first galvano scanner 100a through 313d, mirror 313e, and mirror 313f. When this mirror is in the neutral position, it reflects the incident beam from the right direction in the figure in the forward direction in the figure. By changing the angle of the mirror, the path of the reflected beam is changed to the spot position on the XY table in the horizontal plane in the figure. Then, it can change to the left-right direction (Y-axis direction) in the figure.

  The beam that has passed through the first galvano scanner 100a then enters the mirror of the second galvano scanner 100b. When the mirror is in the neutral position, the incident beam from the back direction in the figure is reflected downward in the figure, but by changing the angle of the mirror, the path of the reflected beam is changed within the vertical plane in the front-rear direction in the figure, that is, XY. The spot position on the table can be changed in the front-rear direction (X-axis direction) in the figure. The beam that has passed through the mirror of the second galvano scanner 100 b is irradiated on the printed circuit board 352 placed on the XY table 353 via the Fθ lens 140. The XY table 353 is driven in the Y-axis direction by the Y-axis drive mechanism 354, and the Y-axis drive mechanism 354 is driven in the X-axis direction by the X-axis drive mechanism 355. Therefore, the XY table 353 is moved and positioned in the XY direction. Is realized. The X-axis drive mechanism 355 is fixed on the bed 356.

  With this configuration, when the swing angle of the rotating shaft 6 is measured by the encoder head 9 and feedback control is performed by a control circuit (not shown) based on the result, the settling waveform does not depend on the position (angle) of the mirror. Since it becomes substantially uniform, a positioning time until convergence within a predetermined accuracy range is constant, and a laser processing machine capable of improving processing accuracy and processing efficiency can be provided.

1 is a cross-sectional view of a moving coil type oscillating actuator device according to the present invention. It is XOY sectional drawing in FIG. It is a figure which shows typically the relationship between the angular displacement of a rotating shaft and the torque constant in the rocking | fluctuation type actuator which concerns on this invention. It is a block diagram of the laser processing machine for printed circuit board drilling to which this invention is applied . It is explanatory drawing of a prior art . It is explanatory drawing of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Permanent magnet 2 Outer yoke 3 Inner yoke 5 Movable coil 6 Rotating shaft 11a, 11b Recessed part 12 Soft magnetic plate 100a, 100b Galvano scanner A Permanent magnet part in the vicinity of the oscillation center (θ = 0) of the rotating shaft B Near the permanent magnet joint C Outer yoke portion in the middle of adjacent swing centers D Outer yoke portion near the swing center (θ = 0) of the rotating shaft

Claims (1)

In a swing actuator device that fixes a permanent magnet as a stator and a coil as a mover to a rotating shaft, and swings the mover within a predetermined angle range,
When the coil is located at both ends of the angle range, the coil on the inner peripheral surface side of the permanent magnet faces the end of one angle range in the circumferential direction along the rotation axis direction. Each one recess is formed,
An oscillating actuator device, wherein a soft magnetic member is disposed in the recess.

Images