JP2008245464A - Elecromagnetic actuator, and laser machining equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic actuator and laser machining equipment capable of improving the operation rate by preventing the temperature rise. <P>SOLUTION: In the electromagnetic actuator in which a rotation angle of a rocking shaft 1 is detected by supporting the rocking shaft 1 having a rotor held at the central part in the shaft direction with a pair of bearings 5a, 5b disposed on both sides of the rotor, by allowing the bearings 5a, 5b to be supported with a cylindrical housing which holds the rotor, by covering the motor with the housing composed of an outer cylinder 4 and brackets 2, 3, and by disposing an angle detecting means at one shaft end of the rocking shaft 1, a gas inflow port 18 and a gas exhaust port 19 are provided which connects the outside and the inside of the outer cylinder 4. In this case, a cover 13 is provided in which the angle detecting means is airtightly covered with an O-ring 25 and a barrier rib 22 against the outside of the housing, and this cover 13 can be connected to the housing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electromagnetic actuator that swings a mirror to deflect a laser in a desired direction, and a laser processing machine that includes such an electromagnetic actuator and performs processing using a laser.

  The galvano scanner used to scan the laser is a device in which a mirror is supported by an oscillating electromagnetic actuator, and the reflection direction of the incident laser is deflected to a desired direction by manipulating the direction of the mirror. Let In order to operate the direction of the mirror, the angle detector detects the oscillation angle of the oscillation shaft and feeds it back, and the servo mechanism is configured by driving the electromagnetic actuator based on the deviation from the target oscillation angle. . In the conventional electromagnetic actuator structure, for example, a coil is fixed to the central section of the integral through-oscillation shaft, and a pair of bearings are arranged adjacent to both ends of the coil, and an angle detector and a mirror are attached to the outside. Are arranged (see, for example, Patent Document 1).

  A laser processing machine for drilling a printed circuit board, which is an example of a laser apparatus having a function of scanning a laser, is an apparatus that irradiates a printed circuit board with a pulsed laser to form a hole for connecting between conductor layers of the circuit board. A conventional printed circuit board drilling laser machine, for example, mounts a printed circuit board and moves the printed circuit board in the XY direction in a horizontal plane, and scans the laser beam on the printed circuit board in the XY direction. And a pair of galvano scanner servo mechanisms (see, for example, Patent Document 2).

  In recent years, the demand for electronic devices such as personal computers, mobile phones, and digital cameras has been increasing year by year, and the demand for printed circuit boards, which are the key components of these devices, has also greatly increased. In order to respond to this increase in demand, the laser processing machine for drilling printed circuit boards is required to improve the processing throughput. In order to increase the number of holes that can be processed per unit time, it is necessary to shorten the time required for laser positioning, and a galvano scanner that performs laser scanning is operated at high speed. At this time, if a large current is passed through the coil to obtain a large acceleration / deceleration torque, heat is generated by the resistance of the coil. In addition, when the flowing current has a high frequency component, the magnet and the inner yoke also generate heat due to the eddy current. As a result, when the temperature inside the galvano scanner rises, there arises a problem that the magnet is demagnetized and the driving torque is lowered, or the torsional rigidity of the swing shaft assembly is lowered and the response of the servo mechanism is deteriorated. Therefore, the cooling of the galvano scanner (that is, the electromagnetic actuator) is an important issue.

  As a cooling structure for a rotary motor, for example, a cooling air passage is provided on the outer periphery of a stator wound with a coil, and a fan is provided on the non-load side of the motor to blow air to the cooling air passage. (See Patent Document 3).

In addition, since the galvano scanner is small in size, a galvano scanner is known to be arranged in an airtight manner inside a container so that air having a constant temperature flows outside the container (Patent Document 4). reference).
Japanese Patent Laying-Open No. 2004-029109 (first page, FIG. 1) Japanese Patent Laid-Open No. 2002-137074 (page 6, FIG. 6) JP 2004-147446 A (page 8, FIG. 1) JP 2001-179479 A (FIG. 1)

  However, the cooling efficiency is poor when a gas for preventing temperature rise is caused to flow around the outer periphery of the galvano scanner.

  An object of the present invention is to provide an electromagnetic actuator and a laser processing machine which can improve the operating rate by solving the above-described problems and preventing temperature rise.

  In order to solve the above-mentioned problem, the first means of the present invention is to support a pair of bearings arranged on both sides of the rotor, with the shaft holding the rotor in the center in the axial direction. An electromagnetic wave that is supported by a cylindrical housing holding a stator and covers the rotor with the housing, and an angle detection means is disposed at one end of the shaft to detect the rotation angle of the shaft. In the actuator, at least two holes connecting the outside and the inside of the housing are arranged on both sides in the axial direction of a space formed by the housing and the pair of bearings.

  In this case, it is possible to provide a cover that hermetically covers the angle detection means with respect to the outside of the housing, and to connect the cover to the housing.

  According to a second means of the present invention, there is provided a laser processing machine comprising an electromagnetic actuator supporting a mirror and deflecting a laser in a desired direction, wherein the electromagnetic actuator employs the first means. It is characterized by being.

  According to the present invention, since the temperature increase of the electromagnetic actuator can be suppressed, the machining efficiency can be improved. In addition, the maintenance interval can be extended.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front sectional view of an electromagnetic actuator according to Example 1 of the present embodiment. The galvano scanner is a so-called moving coil type electromagnetic actuator in which a permanent magnet is disposed on the stator side and a coil is disposed on the swing shaft side.

  In the figure, the swing shaft 1 passes through a load-side bracket 2 and an anti-load-side bracket 3 and is supported by a bearing 5a and a bearing 5b so as to be swingable. The brackets 2 and 3 are connected by an outer cylinder 4 and these form a stator side housing.

  A mirror (not shown) is attached to the load side shaft end on the left side of the drawing via a mount in order to deflect the laser. A pair of left and right coil support members 9a and 9b are fixed to the swing shaft 1, and a coil 8 is fixed between the coil support members 9a and 9b. A magnet 10 disposed outside the coil 8 is fixed to the outer cylinder 4. The inner yoke 6 disposed inside the coil 8 is fixed to the bracket 2 and the bracket 3 via the support pin 7 and the inner yoke support members 16a and 16b. The outer cylinder 4 is formed with a gas inlet 18 and a gas outlet 19 that communicate the outside and the inside of the outer cylinder 4. The gas inlet 18 is disposed as close to the bearing 5b as possible, and the gas outlet 19 is disposed as close to the bearing 5a as possible.

  The light emitting / receiving unit 12 and the grating disk 11 form an optical encoder. The grating disk 11 is fixed to the non-load side of the swing shaft 1. The encoder support plate 17 is fixed to the bracket 3. The light emitting / receiving unit 12 is fixed to the encoder support plate 17 so as to face the grating formed on the surface of the grating disk 11.

  The cover 13 is fitted on the outer periphery of the bracket 3. A signal cable 14 that supplies power to the light emitting and receiving unit 12 and extracts a signal and a power cable 15 that supplies current to the coil 8 are connected to a control device (not shown).

  Next, the operation of this embodiment will be described.

  When air having a predetermined temperature is supplied from the gas inlet 18, the air that has entered the housing (outer cylinder 4) passes through the outer periphery of the magnet 10, the coil 8, and the inner yoke 6 and is discharged from the gas discharge unit 19. . In this state, when a current is supplied to the element wire of the coil 8 via the power cable 15, a Lorentz force is applied to the coil 8 by a magnetic field formed by the magnet 10 and the inner yoke 6 and a current flowing in the element wire, The swing shaft 1 swings. When the swing shaft 1 swings, a pulse corresponding to the swing amount is generated, and the swing angle is detected and fed back to the control device.

  Resistance heat is generated in the coil 8 due to the current supplied to the coil 8, and resistance heat is also generated in the magnet and the inner yoke due to the generated eddy current. The generated heat is supplied from the gas inlet 18 and the gas outlet 19 It is conducted to the air exhausted from the housing and quickly removed to the outside of the housing. As a result, the temperature of the electromagnetic actuator hardly increases.

  Next, a first modification of this embodiment will be described.

  FIG. 2 is a front cross-sectional view showing a first modification of the electromagnetic actuator in FIG. 1, and the same or the same functions as those in FIG. 1 are given the same reference numerals. Only the differences will be described below.

  In the figure, the inner yoke support member 16a and the bracket 2 are provided with a vent hole 21a. The inner yoke support member 16b and the bracket 3 are provided with vent holes 21b. An O-ring 25 is disposed in a groove provided on the outer periphery of the bracket 3.

  A partition wall 22 that is integral with the cover 13 is provided at the center of the cover 13 in the axial direction. A terminal block A 23 and a terminal block B 24 are arranged on the partition wall 22. The terminal block A23 and the terminal block B24 are shielded by a mold, and gas does not flow through the partition wall 22. The signal cable 14 and the power cable 15 are connected to the control device via the terminal block A23 and the terminal block B24, respectively.

  Next, operations different from the case of FIG. 1 in the first modification will be described.

  In the first modification, the inner yoke support member 16b and the bracket 3 are provided with the air holes 21b, so that no pressure gradient is generated between the left and right surfaces of the bearing 5b. Further, the partition 22 and the O-ring 25 constitute a portion of the cover 13 that houses the grating disk 11 in an airtight structure. Therefore, even if air having a pressure higher than atmospheric pressure is supplied from the gas inlet 18, the air that has flowed into the housing does not flow out to the encoder side on the right side in the figure, but the central inner yoke 6, coil 8, magnet 10 flows out from the gas outlet 19 or the vent 21a. As a result, there is no problem that air is blown off the lubricating grease in the bearing 5b, resulting in poor lubrication, or the grease is attached to the grating disk 11 or the light emitting / receiving unit 12 and the encoder does not function. .

  The same applies to the other embodiments described below. However, when it is desired to avoid air blowing to the mirror attached to the swing shaft 1, an exhaust pipe for inducing air is attached to the vent hole 21a. The exhausted air may be prevented from hitting the mirror. Further, helium or hydrogen may be used instead of air. Conversely, air may be caused to flow through the gap between the inner yoke 6, the coil 8, and the magnet 10 by performing vacuum exhaust from the gas inlet 18.

  Next, a second modification of this embodiment will be described.

  FIG. 3 is a front cross-sectional view showing a second modification of the electromagnetic actuator in FIG. 1, and those having the same or the same functions as those in FIG. Only the differences will be described below.

  In the figure, a cylindrical gas jacket 41 having a space 41 a therein is disposed at the outer central portion of the outer cylinder 4. The gas inlet 18 is disposed in the gas jacket 41. The outer cylinder 4 is formed with a flow path 42 that communicates the space 41 a with the inside of the outer cylinder 4. A plurality of flow paths 42 are arranged in the circumferential direction of the outer cylinder 4.

  Next, the air flow of the second modification will be described.

  The air flowing in from the gas inlet 18 flows into the gas flow path 42 through the space 41a, flows through the gap between the magnet 10 and the coil 8, and flows out from the gas outlet 19 and the vent hole 21a.

  In the case of this second modification, air is supplied from the central portion, and therefore, for example, the temperature difference at both ends in the axial direction of the coil 8 can be made smaller than in the case of FIG.

  FIG. 4 is a front sectional view of another electromagnetic actuator according to Example 2 of the present embodiment. This electromagnetic actuator is a so-called moving magnet type electromagnetic actuator in which a coil is arranged on the stator side and a magnet is arranged on the swing shaft side, and the configuration is almost the same as the moving coil type electromagnetic actuator. Only the different components will be described.

  A magnet 10 is fixed to the swing shaft 1. On the outer side in the radial direction of the magnet 10, a coil 8 fixedly molded to an outer yoke 30 made of laminated steel plates is disposed. The outer yoke 30 is fixed to the outer cylinder 4. Therefore, the magnet 10 oscillates while receiving a Lorentz force in the circumferential direction due to the action of the magnetic field formed in the radial direction by the magnet 10 and the outer yoke 30 and the current flowing through the wire of the coil 8. In the illustrated case, the outer yoke 30 is fixed to the outer cylinder 4 and the brackets 2 and 3, so that the gas inlet 18 is connected to the outer cylinder 4 and the bracket 2, and the gas outlet 19 is connected to the outer cylinder 4 and the bracket 3. Is provided.

  Since the operation is substantially the same as that of the first modified example, a duplicate description is omitted.

  Further, as shown in FIG. 5, the air flow path may be the same as that shown in FIG.

  FIG. 6 is a configuration diagram of a printed circuit board drilling laser processing machine according to Example 3 of the present embodiment, and illustrations of portions not related to the essence of the invention are omitted.

  In the figure, a laser 30 output from a laser oscillator 410 is reflected by mirrors 413a and 413b, shaped through an optical beam processing system including a collimator 412, an aperture 414, and the like, and further mirrors 413c and 413d. Then, the light is reflected by the mirror 413e and the mirror 413f and is incident on the mirror 100am supported by the first electromagnetic actuator 100a. When the mirror 100am is in the neutral position, it reflects the laser 30 incident from the right in the figure in the forward direction in the figure, and when the angle is changed, the path of the reflected laser 30 is shown in the horizontal plane in the figure, that is, on the XY table. The spot position is changed in the horizontal direction (Y-axis direction) in the figure.

  The laser 30 reflected by the mirror 100am then enters the mirror 100bm of the second electromagnetic actuator 100b. When the mirror 100bm is in the neutral position, it reflects the laser 30 incident from the back direction in the figure downward in the figure, and when the angle is changed, the path of the reflected laser 30 is within the vertical plane in the front-rear direction in the figure, that is, The spot position on the XY table is changed in the front-rear direction (X-axis direction) in the figure. The laser beam 30 reflected by the mirror 100bm passes through the Fθ lens 140 and enters the printed circuit board 452 placed on the XY table 453. The XY table 453 is driven in the Y-axis direction by the Y-axis drive mechanism 454, and the Y-axis drive mechanism 454 is driven in the X-axis direction by the X-axis drive mechanism 455. Therefore, the XY table 453 is positioned in the XY direction. . The X-axis drive mechanism 455 is fixed on the bed 456. The galvano scanners 430a and 430b have the air cooling structure as in the first and second embodiments.

It is front sectional drawing of the electromagnetic actuator which concerns on Example 1 of this invention. It is front sectional drawing which shows the 1st modification of the electromagnetic actuator in FIG. It is front sectional drawing which shows the 2nd modification of the electromagnetic actuator in FIG. It is front sectional drawing of the other electromagnetic actuator which concerns on Example 2 of this invention. It is front sectional drawing which shows the modification of the electromagnetic actuator in FIG. It is a block diagram of the laser processing machine for printed circuit board drilling which concerns on Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oscillation shaft 2 Bracket 3 Bracket 4 Outer cylinder 5a, 5b Bearing 13 Cover 18 Gas inlet 19 Gas exhaust 22 Bulkhead 25 O-ring

Claims (4)

The shaft holding the rotor at the center in the axial direction is supported by a pair of bearings arranged on both sides of the rotor, and the pair of bearings is supported by a cylindrical housing holding the stator. In an electromagnetic actuator that covers a child with the housing and arranges an angle detection means at one shaft end of the shaft to detect a rotation angle of the shaft,
An electromagnetic actuator comprising two holes for connecting the outside and the inside of the housing on both sides in the axial direction of a space formed by the housing and the pair of bearings.   The electromagnetic actuator according to claim 1, wherein a cover for airtightly covering the angle detection means with respect to the outside of the housing is provided, and the cover is connected to the housing.   3. The electromagnetic actuator according to claim 2, wherein an axial hole that connects spaces on both sides in the axial direction of the bearing is provided in the housing portion that holds the bearing close to the angle detection unit. The electromagnetic actuator according to any one of claims 1 to 3,
A mirror supported by the electromagnetic actuator;
With
A laser processing machine characterized in that a laser is deflected in a desired direction by the mirror.

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