JP2009303451A - Rotating shaft structure of motor for galvano-scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotating shaft structure of a motor for a galvano-scanner achieving low inertia and high rigidity by a simple structure. <P>SOLUTION: In the rotating shaft structure of the motor for the galvano-scanner, a rotor 70 composed of a permanent magnet is rotated by controlling a current flowing through a stator 54, and a rotating shaft 52 having the rotor is swingingly operated. In the rotating shaft 52, a through-hole 52b penetrated from an outer peripheral surface 52a to an outer peripheral surface 52a on an opposite side across the axial center Q, is formed. The permanent magnet is inserted into the interior of the through-hole 52b to constitute the rotor 70. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotating shaft structure of a galvano scanner motor capable of positioning a mirror at a high speed regardless of a swing angle.

  As an optical deflector for polarizing laser light, a galvano scanner motor that swings a galvano mirror irradiated with laser light at a high speed within a finite angle is used. The rotor arranged on the rotation shaft of the galvano scanner motor is provided with a permanent magnet at a position corresponding to the stator of the toothless structure, and the rotation shaft controls the current flowing through the stator. Oscillates.

As the rotor of the galvano scanner motor, a two-pole rotor is often used. Further, since the rotating shaft is required to have high responsiveness in the swinging operation, it is desired that the rotating shaft has low inertia and high rigidity.
As a structure in which the two-pole structure is provided on the rotating shaft, for example, there is a structure in which a permanent magnet is attached to the outer peripheral surface of the rotating shaft by bonding (see, for example, Patent Document 1). On the other hand, in the axial direction of the rotating shaft, there is one in which the entire portion corresponding to the rotor is replaced with a permanent magnet (the rotating shaft and the permanent magnet are bonded in the axial direction by bonding) (for example, see Patent Document 2). ).
JP-A-11-275790 Japanese Utility Model Publication No. 62-119182

However, since the thickness of the rotating shaft is constant in the structure attached to the outer peripheral surface, the thickness of the rotating shaft is reduced by the thickness of the permanent magnet, and the rigidity of the rotating shaft is reduced. In particular, since it is difficult to manufacture a permanent magnet to be attached in a ring shape, segment-type permanent magnets separated in the circumferential direction are often used, and each separated permanent magnet is bent on the rotating shaft. Since it does not contribute much to the rigidity, it is difficult to increase the rigidity.
Further, when the diameter of the rotating shaft is increased in order to increase the rigidity, the thickness of the permanent magnet must be reduced, so that the torque is reduced. Also, increasing the diameter of the rotating shaft can achieve high rigidity, but cannot achieve low inertia.
Furthermore, in the structure that is bonded to the outer peripheral surface by adhesion, the permanent magnet may be peeled off, and the reliability cannot be increased.

On the other hand, in the structure in which the rotating shaft and the permanent magnet are joined in the axial direction, it is difficult to increase the rigidity because the rotating shaft and the permanent magnet are joined by bonding. In particular, as in Patent Document 2, it is necessary to attach a cylindrical reinforcing member for increasing rigidity to the outer periphery of the rotating shaft. This reinforcing member is made of a non-magnetic material so that the magnetic path of the permanent magnet is not closed. It must be done and it will be expensive.
Moreover, since a cylindrical reinforcement member must be processed so that it may become concentric with a rotating shaft, accuracy is required. In particular, in order to increase the torque, it is necessary to reduce the gap with the stator and reduce the thickness of the reinforcing member, which requires accuracy.
Further, in order to finish the bearing insertion portion of the rotating shaft with high accuracy, the rotating shaft must be processed after bonding, which requires a processing man-hour. Moreover, it is difficult to process a rotating shaft having a permanent magnet in part.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a rotating shaft structure of a galvano scanner motor that achieves low inertia and high rigidity with a simple structure.

In the present invention, in the rotating shaft structure of the galvano scanner motor that rotates the rotor composed of permanent magnets by controlling the current flowing through the stator and swings the rotating shaft having the rotor, the rotation The shaft is formed with a through hole penetrating from the outer peripheral surface to the outer peripheral surface on the opposite side across the shaft center, and a permanent magnet is inserted into the through hole to constitute a rotor.
According to this structure, the diameter of the rotating shaft can be increased to a position where a gap with the stator is ensured. Further, the permanent magnet can be securely attached to the rotating shaft by inserting it into the through hole.

Moreover, you may form the outer surface of the said permanent magnet exposed from opening of the said through hole in circular arc shape along the outer peripheral surface of the said rotating shaft.
According to this configuration, it is possible to easily manage the gap between the rotor and the stator.

Further, the permanent magnet may be fixed to the through hole with an adhesive.
According to this structure, a permanent magnet can be attached to a rotating shaft by a simple method.

According to the present invention, a through hole is formed in the rotating shaft from the outer peripheral surface thereof to the opposite outer peripheral surface with the shaft center interposed therebetween, and a permanent magnet is inserted into the through hole to constitute a rotor. Therefore, compared with the case where a permanent magnet is provided on the outer peripheral surface of the rotating shaft, the diameter of the rotating shaft can be increased to a position that ensures a gap with the stator, and the rigidity of the rotating shaft can be increased. .
Further, by inserting a permanent magnet into the through hole, the permanent magnet comes to play a role of increasing the rigidity of the rotating shaft as compared with the case of making a segment type permanent magnet.
Furthermore, by inserting the permanent magnet into the through hole, the permanent magnet can be made larger than when the permanent magnet is attached to the outer peripheral surface, so that high torque can be obtained.
In addition, as compared with the case where the rotating shaft is joined in the axial direction, the rotating shaft is continuous in the direction of the rotating axis, so that it does not have a structure that receives the bending force with adhesive strength, and rigidity is ensured. As a result, the reliability of the motor is improved.
Furthermore, since the rotating shaft is continuous in the direction of the rotating axis, there is no need to post-process the bearing insertion portion, and the accuracy of the bearing portion can be ensured only by processing the rotating shaft separately.
Further, by inserting the permanent magnet into the through hole, there is no concern about peeling or the like, compared to the case where the permanent magnet is attached to the outer peripheral surface, and the permanent magnet can be securely attached to the rotating shaft.

FIG. 1 is a diagram illustrating a configuration of a laser processing apparatus 1 according to the present embodiment. FIG. 2 is an enlarged view showing a state in which the scanner mirror 40A is attached to the galvano scanner motor 41A (hereinafter simply referred to as a motor) shown in FIG.
The laser processing apparatus 1 includes a laser oscillator 2, a scanner optical apparatus 3, and a pair of mirrors 4A and 4B, which are optical elements that guide the laser light 45 emitted from the laser oscillator 2 to the scanner optical apparatus 3. These are placed and fixed on a plate-like stone surface plate 5.

The laser oscillator 2 oscillates a laser beam 45 having a wavelength corresponding to the laser medium. The laser oscillator 2 includes a rectangular parallelepiped oscillator main body 20 including a laser resonator (not shown), and a laser emission port 21 opened at a tip portion 20A of the oscillator main body 20.
Examples of the laser oscillator 2 include a solid laser oscillator, a liquid laser oscillator, a gas laser oscillator, a semiconductor laser oscillator, and a free electron laser oscillator.

  An XYZ axis stage 22 is provided on the lower side of the oscillator body 20 on the front end portion 20A side and the rear end portion 20B side. The XYZ axis stage 22 is fixed to the stone surface plate 5 with screws. In general, the stone surface plate 5 has a very high planar accuracy, so that the optical axis of the laser oscillator 2 can be finely adjusted by adjusting the XYZ axis stage 22. Further, since the stone surface plate 5 has a very low thermal conductivity, even if the laser oscillator 2 generates heat, it is possible to minimize the thermal effect on other optical elements.

  The scanner optical device 3 deflects the laser light 45, an AOM (acousto-optic modulation element) 30 that modulates the intensity of the laser light 45 output from the laser oscillator 2, a dynamic focus lens 31 that adjusts the focus of the laser light 45, and the laser light 45. The optical element is mounted on a height adjusting stage 33 extending linearly for aligning the optical axis with the mirror 4B. This height adjustment stage 33 is provided between the dynamic focus lens 31 and the scanner head 32, and forms a light output from the dynamic focus lens 31 and inputs it to the scanner head 32 as a lens 34 as an optical element. A pair of lenses 35A and 35B as optical elements for shaping the laser light 45 incident on the AOM 30 are attached.

The scanner head 32 includes a box-shaped housing 42 having an open bottom surface, and motors 41A and 41B are provided on the top and sides of the housing 42.
The rotating shaft 52 of the motor 41A extends in the left-right direction in FIG. 1, and a scanner mirror 40A for deflecting the laser beam 45 is attached to the tip of the rotating shaft 52. The scanner mirror 40A is configured such that the angle of the mirror can be changed by appropriately rotating (rotating or swinging) the rotating shaft 52 of the motor 41A in the R direction (see FIG. 2).
On the other hand, the rotating shaft of the motor 41B extends in the vertical direction in FIG. 1, and at its tip, a scanner mirror that deflects the laser light 45 in a direction at a predetermined angle with respect to the deflection direction of the scanner mirror 40A. 40B is attached. The scanner mirror 40B can change the angle of the mirror by rotating the rotation shaft of the motor 41B.
These scanner mirrors 40A and 40B are disposed inside the casing 42, and an inlet (not shown) for guiding the laser beam 45 is formed in the side of the casing 42.

  The height adjustment stage 33 where the casing 42 is disposed is provided with an emission port 43 that emits the light deflected by the scanner mirrors 40A and 40B. Thus, the scanner head 32, the lens 34, and the emission port 43 constitute a deflection module that deflects the laser light 45 output from the laser oscillator 2. The laser beam 45 deflected by this deflection module passes through the emission port 43 and is directed to the working area 46 (workpiece, see FIG. 2).

  When the laser beam 45 is deflected by the scanner head 32 and the object is scanned with the laser beam 45, the dynamic focus lens 31 makes the irradiation spot diameter of the laser beam 45 on the scanning surface of the object substantially constant regardless of the irradiation position. The focal length of the laser beam 45 is varied so as to be maintained. The dynamic focus lens 31 is driven in the optical axis direction by a motor (not shown) to vary the focal length of the laser light 45. Further, when the object is a three-dimensional scanning plane, the dynamic focus lens 31 is controlled by the control unit 6 so that the object is focused on the scanning plane. The motor (not shown) and the motors 41A and 41B of the scanner head 32 are controlled by the control unit 6. The control unit 6 controls the motor of the dynamic focus lens 31 and the motors 41A and 41B of the scanner head 32 in synchronization with each other in order to adjust the focal length based on the irradiation position of the laser beam 45 on the scanning surface. Instead of the dynamic focus lens 31, an fθ lens may be used as the focal length adjustment unit.

As described above, the AOM 30 modulates the intensity of the continuous wave laser beam or pulse laser beam output from the laser oscillator 2 and is controlled by the control unit 6. The intensity of the laser beam 45 is adjusted according to the scanning speed of the laser beam 45 defined by the drive amount of the motors 41A and 41B of the scanner head 32 so that the processing degree such as the laser processing depth on the scanning surface of the scanner head 32 is always kept constant. Variable. That is, when the scanning speed of the laser beam 45 is high, the control unit 6 increases the intensity of the laser beam 45 or the density of the laser beam 45 because the energy per unit area decreases. If the laser beam 45 is slow, control is performed to reduce the intensity of the laser beam 45 or the density of the laser beam 45, and control to maintain the energy per unit area when the laser beam 45 is scanned substantially constant.
The density of the laser beam 45 is defined by the number of pulses per unit time of the pulse laser beam, and the energy of the laser beam 45 per unit area can be varied by varying the laser beam density.

The motors 41A and 41B of the scanner head 32 are provided with encoders 44A and 44B that output digital pulse signals SA and SB having the number of pulses corresponding to the rotation amounts of the scanner mirrors 40A and 40B to the control unit 6, respectively.
The control unit 6 counts the digital pulse signals SA and SB, specifies the rotation amounts of the scanner mirrors 40A and 40B based on the count values, and specifies the XY coordinate values of the current laser light irradiation position.
Further, the control unit 6 performs negative feedback control by outputting to each of the motors 41A and 41B so as to cancel out the deviation between the target value of the laser light irradiation position and the current XY coordinate value. Thus, in the control unit 6, the encoders 44A and 44B that output the digital pulse signals SA and SB and the control unit 6 constitute a closed loop control system, and the motors 41A and 41B are driven with high accuracy. Will be compensated for. Thereby, highly accurate motor control, that is, highly accurate irradiation position control on the processed surface of the workpiece is realized.

  Examples of such a laser processing apparatus 1 include, for example, remote laser welding, an optical modeling system with a relatively long working distance, a drawing system that requires high drawing accuracy (drawing to recognize characters such as mere manufacturing date) Can be used).

  3 is a side sectional view of the motor 41A, and FIG. 4 is a sectional view taken along line IV-IV in FIG. FIG. 5 shows a side view and a sectional view of the rotating shaft 52 used in the motor 41A. Since the motors 41A and 41B have the same structure, the motor 41A will be described in the following description, and the description of 41B will be omitted.

  As shown in FIG. 3, the motor 41A includes a cylindrical stator yoke 56, a rotary shaft 52 rotatably supported by bearings 57a and 57b inside the stator yoke 56, and one of the rotary shafts 52. It is comprised with the encoder part 58 attached to the axial end part (right side edge part in FIG. 3) side.

  As shown in FIG. 3 and FIG. 4, four coils 54 (stators) fixed with mold resin are provided on the cylindrical inner peripheral surface of the stator yoke 56 at intervals in the circumferential direction. The length of the coil 54 extends over the entire length between the bearings 57a and 57b. The coil 54 generates a magnetic field when a current supplied from a power supply unit (not shown) flows, and generates a rotating torque on the rotating shaft 52. The supplied current value is variably controlled by a control unit (not shown).

  Further, the above-described bearing 57 a is provided on the left side portion of the stator yoke 56. Further, the above-described bearing 57b is provided on the right side portion of the stator yoke 56, and the rotating shaft 52 is rotatably supported by these bearings 57a and 57b. A support member 53 that supports the left side of the outer ring of the bearing 57a via a web washer 65 and a spacer 66 is attached to the left end portion of the stator yoke 56 by a fastening member 55 such as a screw. In addition, the right side of the inner ring of the bearing 57 a is supported by a step portion formed on the rotating shaft 52. The right side of the outer ring of the bearing 57 b is supported by the base member 60, and the inner side of the inner ring of the bearing 57 b is supported by a step portion formed on the rotating shaft 52. The rotating shaft 52 is rotatably fixed via bearings 57a and 57b by the right side pressing force of the web washer 65.

The encoder unit 58 includes a base member 60 that closes the opening on the right side of the stator yoke 56 in FIG. 3, an encoder slit plate 61 that rotates together with the rotating shaft 52, and a light emitting / receiving element 62 that emits and receives light. ing.
The base member 60 is provided with the bearing 57b described above, and supports one end of the rotating shaft 52 in a rotatable manner. The base member 60 is formed so as to cover the side of the right end portion of the rotating shaft 52, and the light emitting / receiving element 62 is attached to the base member 60 by a fastening member 64 such as a screw. The light emitting / receiving element 62 is arranged to face the encoder slit plate 61 in order to irradiate and receive light toward the encoder slit plate 61.

  As shown in FIG. 3, the encoder slit plate 61 is attached to one shaft end of the rotating shaft 52 via a support member 63 (fixed to the step 51a with a screw). The encoder slit plate 61 is attached so that its plane is perpendicular to the rotation axis of the rotation shaft 52, and a slit 61a is formed at a position corresponding to the light emitting / receiving element 62 described above. Thereby, the light receiving / emitting element 62 irradiates light toward the encoder slit plate 61, and the rotation angle of the rotary shaft 52 is accurately determined by checking the difference in reflected light depending on the presence or absence of the slit 61a of the rotating encoder slit plate 61. It is well detectable.

  As shown in FIGS. 4 and 5, the rotary shaft 52 has a round bar shape having two steps 51a and 51b at both ends, and the above-described bearings 57a and 57b are attached to the steps 51b. A scanner mirror 40 </ b> A (see FIG. 2) is attached to the left shaft end of the rotation shaft 52, and rotates together with the rotation shaft 52.

  As shown in FIGS. 5A and 5B, the rotation shaft 52 has a through hole 52 b that penetrates from the outer peripheral surface 52 a of the rotation shaft 52 in the radial direction. As shown in FIG. 5 (b), the through hole 52b is formed symmetrically with respect to the center line passing through the axis Q of the rotating shaft 52, and the inertial force generated when the rotating shaft 52 rotates can be minimized. It is set to be constant.

  The length of the through hole 52b in the axial direction corresponds to the length of the coil 54 described above, and is formed long as long as the rigidity of the rotating shaft 52 can be ensured. In addition, the area of the permanent magnet 70 exposed from the outer peripheral surface 52a of the rotating shaft 52 can be secured and the magnetic resistance can be reduced enough to ensure sufficient rotational torque obtained by the permanent magnet 70 described later. The inner volume of the through hole 52b is determined so that the volume can be secured. The inner corner of the through hole 52b has an appropriate R shape to prevent stress from concentrating when an external force is applied.

  As shown in FIGS. 3 and 4, a permanent magnet 70 (rotor) is attached inside the through hole 52b so as to be embedded in the through hole 52b without a gap. The permanent magnet 70 functions as a rotor on the rotating shaft 52. The permanent magnet 70 is firmly bonded to the through hole 52b with an adhesive.

As shown in FIG. 4, the outer surface 70a of the permanent magnet 70 exposed from the outer peripheral surface 52a of the rotating shaft 52 is flush with the outer peripheral surface 52a of the rotating shaft 52, and the outer peripheral surface 52a of the rotating shaft 52 in cross section. In addition, a circular shape (a circular arc shape that is flush with the outer peripheral surface 52a) is formed. Thereby, the inertial force at the time of rotation of the rotating shaft 52 is made as constant as possible.
Further, the diameters of the outer peripheral surface 52a and the outer surface 70a are set to the maximum diameters that can secure a gap G with the coil 54 and obtain high torque. That is, by making the outer peripheral surface 52a and the outer surface 70a the same surface, the gap G can be easily secured and adjusted, and the diameter of the rotating shaft 52 can be secured to the maximum.

  According to the rotating shaft structure of the galvano scanner motor according to the embodiment of the present invention, the rotating shaft 52 is formed with the through hole 52b penetrating radially outward from the outer peripheral surface 52a of the rotating shaft 52. Since the rotor is configured by inserting the permanent magnet 70 into the hole 52b, the diameter of the rotating shaft 52 is compared with the coil 54 as compared with the case where the permanent magnet is attached to the outer peripheral surface of the rotating shaft 52. The gap G can be increased to a position where the gap G is secured, and the rigidity of the rotating shaft 52 can be increased.

  Further, by inserting the permanent magnet 70 into the through hole 52b without a gap, the permanent magnet 70 plays a role of increasing the rigidity of the rotating shaft 52 as compared with the case of using a segment type permanent magnet.

  Furthermore, by inserting the permanent magnet 70 into the through hole 52b, the volume of the permanent magnet 70 can be increased while ensuring the gap G, as compared with the case where the permanent magnet is attached to the outer peripheral surface. Therefore, high torque can be obtained as the motors 41A and 41B without increasing the magnetic resistance.

  Further, by setting the portion to which the permanent magnet 70 is attached as the through hole 52b, the portions of the rotating shaft 52 remain on both sides of the through hole 52b in the cross section of the through hole 52b, and the rotating shaft 52 is continuous in the direction in which the rotating axis extends. Therefore, as compared with the case where the rotating shaft is joined in the axial direction using an adhesive, the structure is not subjected to a bending force with adhesive strength, and rigidity is ensured. As a result, the reliability of the motor is improved.

  Furthermore, since the rotating shaft 52 is continuous in the direction of the rotating axis, there is no need to post-process the bearing insertion portion after the permanent magnet 70 is mounted, and the accuracy of the steps 51a and 51b can be improved by processing the rotating shaft 52 alone. Can be secured.

  Furthermore, by inserting the permanent magnet 70 into the through hole 52b, there is no fear that the permanent magnet 70 is peeled off as compared with the case where the permanent magnet is attached to the outer peripheral surface, and the permanent magnet 70 is reliably attached to the rotating shaft 52. 70 can be attached.

  Furthermore, since the permanent magnet 70 has only to be formed in a substantially rectangular parallelepiped shape, it is not necessary to form the permanent magnet in a cylindrical shape or a segment shape, and the permanent magnet 70 can be easily manufactured.

  On the other hand, the outer surface 70a of the permanent magnet 70 exposed from the through hole 52b is formed in a flat arc shape along the outer peripheral surface 52a of the rotating shaft 52, so that the outer surface 70a is formed outside the outer peripheral surface 52a of the rotating shaft 52. There is no protruding portion, and the inertial force during rotation of the rotating shaft 52 is made as constant as possible. Further, the gap G with the coil 54 can be set to a minimum. In addition, the gap G can be easily secured and adjusted, and the diameter of the rotating shaft 52 can be secured to the maximum.

  Furthermore, since the permanent magnet 70 is fixed to the through hole 52b with an adhesive, the permanent magnet 70 can be attached to the rotating shaft 52 by a simple method, and the assembly work can be reduced.

The best mode for carrying out the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications and changes can be made based on the technical idea of the present invention. .
In the present embodiment, the permanent magnet 70 is attached to the through hole 52b by using an adhesive. However, if sufficient attachment strength can be secured for the rotation of the rotary shaft 52, the permanent magnet 70 is attached to the through hole 52b. The permanent magnet 70 can be fitted (inserted) and attached without using an adhesive.

It is a schematic diagram of the laser processing apparatus using the motor for galvano scanners. It is a schematic diagram which expands and shows the state in which the scanner mirror was attached to the motor shown in FIG. It is side part sectional drawing of the motor for galvano scanners. It is IV-IV sectional drawing of FIG. (A) is a side view of a motor rotating shaft, (b) is a VV sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 2 Laser oscillator 3 Scanner optical apparatus 4A, 4B Mirror 5 Stone surface plate 6 Control unit 20 Oscillator main body 20A Front end part 20B Rear end part 21 Laser emission port 22 XYZ axis stage 30 AOM
DESCRIPTION OF SYMBOLS 31 Dynamic focus lens 32 Scanner head 33 Adjustment stage 34 Lens 35A Lens 40A, 40B Scanner mirror 41A, 41B Galvano scanner motor 42 Case 43 Outlet 44A Encoder 45 Laser light 46 Working area 51a, 51b Step 52 Rotating shaft 52a Outer circumference Surface 52b Through-hole 52c Mounting hole 53 Support member 54 Coil 55 Fastening member 56 Stator yoke 57a, 57b Bearing 58 Encoder unit 60 Base member 61 Encoder slit plate 61a Slit 62 Light emitting / receiving element 63 Support member 64 Fastening member 65 Web washer 66 Spacer 70 Permanent magnet (rotor)
70a outer surface SA digital pulse signal Q axis

Claims (3)

In the rotating shaft structure of the galvano scanner motor that controls the rotation of the rotor composed of permanent magnets by controlling the current flowing through the stator and swings the rotating shaft having this rotor.
A rotation of a galvano scanner motor characterized in that a through-hole penetrating radially inward from an outer peripheral surface of the rotary shaft is formed, and a permanent magnet is inserted into the through-hole to constitute a rotor. Axis structure.   2. The rotating shaft structure of a galvano scanner motor according to claim 1, wherein an outer surface of the permanent magnet exposed from the opening of the through hole is formed in an arc shape along an outer peripheral surface of the rotating shaft. .   The rotating shaft structure of the motor for a galvano scanner according to claim 1 or 2, wherein the permanent magnet is fixed to the through hole with an adhesive.

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