WO2024013985A1

WO2024013985A1 - Galvano scanner and laser beam machine

Info

Publication number: WO2024013985A1
Application number: PCT/JP2022/027875
Authority: WO
Inventors: 尚弘高橋
Original assignee: 三菱電機株式会社
Priority date: 2022-07-15
Filing date: 2022-07-15
Publication date: 2024-01-18
Also published as: JP7241994B1; TW202404726A; JPWO2024013985A1

Abstract

A galvano scanner (32) according to the present disclosure comprises: a motor (35); and an electrolytic corrosion suppression unit (37). The motor (35) has a rotor (340) having a permanent magnet (341) which rotates about the rotary axis thereof and shafts (342, 343) connected to opposing sides of the permanent magnet (341) along the rotary axis, and a stator (330) disposed at a predetermined distance from the rotor (340). The electrolytic corrosion suppression unit (37) is provided to one end, of two ends of the motor (35), that is not provided with a galvano mirror (31) in the direction of the rotary axis, and electrically connects the stator (330) and the rotor (340).

Description

Galvano scanner and laser processing machine

The present disclosure relates to a galvano scanner and a laser processing machine that rotationally drive a galvanometer mirror that irradiates a desired position on a workpiece with a laser beam from a laser light source.

In a laser processing machine, a galvano scanner controls the irradiation position of the laser beam on the workpiece, that is, the processing position. A galvano scanner is a servo motor that rotates a galvanometer mirror attached to one end of a shaft. A galvano scanner has a bearing that supports a shaft. In one example, the bearing includes a cylindrical inner ring that holds a shaft, a cylindrical outer ring that is arranged outside the inner ring concentrically with the inner ring, and rolling elements that are arranged between the inner ring and the outer ring. It is a rolling bearing. In bearings, an oil film exists between the inner and outer rings and the rolling elements.

Due to the influence of eddy currents in the magnets when the galvano scanner is driven, a shaft voltage, which is a potential difference, may be generated between the inner and outer rings of the bearing. During operation of a laser processing machine, if the oil film of the bearing goes from insulating the inner ring and outer ring to a state where the oil film breaks at a certain moment and the inner ring and outer ring become electrically connected, the inner ring and outer ring may become electrically connected. Electric discharge may occur and damage the bearing. Such bearing damage is called electrolytic corrosion. When electrolytic corrosion occurs, the inside of the bearing is damaged, which prevents smooth rotation of the bearing and may adversely affect control of the laser beam irradiation position.

Patent Document 1 discloses a structure for preventing electrolytic corrosion of a bearing of a rotor shaft of a motor generator for driving a vehicle. In the technique described in Patent Document 1, an oil chamber is provided at one end in the axial direction of the rotor shaft in the housing of the motor generator. When the motor generator is in a high rotation state, by applying hydraulic pressure to the oil chamber in the housing, thrust force, which is an axial force, is applied to the rotor shaft, and the rolling elements of the bearing and the inner and outer rings are actively rotated. make contact with This breaks the oil film between the rolling elements and the inner and outer rings of the bearing, strengthens conduction, and suppresses the electrolytic corrosion described above.

Japanese Patent Application Publication No. 2020-014359

The technology described in Patent Document 1 is aimed at suppressing electrical corrosion in motor generators for driving vehicles such as automobiles. Therefore, no particular problem occurs even if a thrust force is applied to the rotor shaft by hydraulic pressure and the rolling elements of the bearing are brought into contact with the inner ring and the outer ring. However, the technique described in Patent Document 1 cannot be applied to a product that requires high positioning accuracy during operation, such as a galvano scanner for a laser processing machine. Specifically, in the technology described in Patent Document 1, the preload of the bearing changes depending on whether hydraulic pressure is applied or not, and the rigidity of the bearing in the radial direction changes, which affects the accuracy of the product, specifically the laser beam. This may have a significant impact on the accuracy of the irradiation position. In other words, it is difficult to apply the technology described in Patent Document 1, which has a large impact on positional accuracy control, to a galvano scanner that drives a galvano mirror in a laser processing machine that requires precise positional control of a laser beam. There was a problem that.

The present disclosure has been made in view of the above, and an object of the present disclosure is to provide a galvano scanner that can suppress electrolytic corrosion while suppressing axial displacement between an inner ring and an outer ring compared to the conventional one. shall be.

In order to solve the above-mentioned problems and achieve the objectives, a galvano scanner according to the present disclosure includes a motor and an electrolytic corrosion suppressing section. A motor has a rotor having a permanent magnet that rotates about an axis of rotation and a shaft connected to either side of the permanent magnet along the axis of rotation, and a stator that is positioned at a fixed distance from the rotor. The electrolytic corrosion suppressing section is provided at one of the two ends of the motor in the direction of the rotation axis, where the galvanometer mirror is not provided, and electrically connects the stator and rotor.

The galvano scanner according to the present disclosure has the effect of suppressing electrolytic corrosion while suppressing displacement in the axial direction between the inner ring and the outer ring compared to the past.

A diagram showing an example of the configuration of a laser processing machine according to Embodiment 1. A diagram schematically showing an example of the configuration of a galvano scanner according to Embodiment 1. A cross-sectional view showing an example of the configuration of a grounding structure used in the galvano scanner according to Embodiment 1. A diagram schematically showing another example of the configuration of the galvano scanner according to Embodiment 1. A diagram schematically showing another example of the configuration of the galvano scanner according to Embodiment 1.

Below, a galvano scanner and a laser processing machine according to an embodiment of the present disclosure will be described in detail based on the drawings.

Embodiment 1.
FIG. 1 is a diagram showing an example of the configuration of a laser processing machine according to the first embodiment. The laser processing machine 1 performs a drilling process on a workpiece W to be machined by irradiating a pulsed laser beam L. An example of the workpiece W to be processed is a printed circuit board or an IC (Integrated Circuit) package board mounted on an electronic device or the like. The work W to be processed may be any object that can be subjected to drilling, and may be any object other than the above-described printed circuit board or IC package board.

In FIG. 1, the X-axis, Y-axis, and Z-axis are three axes that are perpendicular to each other. The X axis and the Y axis are horizontal axes. The Z axis is a vertical axis. The laser processing machine 1 performs a drilling process to form a plurality of holes dispersed in the X-axis direction and the Y-axis direction at high speed.

The laser processing machine 1 includes a laser oscillator 10 that emits a laser beam L, a laser optical element 20 that shapes the shape of the laser beam L and adjusts the output, and a processing head 30 that irradiates the laser beam L to a desired position. , and a workpiece transfer table 40 that holds the workpiece W to be processed.

The laser oscillator 10 outputs a pulsed laser beam L. The pulsed laser beam L is, for example, infrared light. An example of laser oscillator 10 is a carbon dioxide (CO ₂ ) laser. The peak wavelength of the pulsed laser beam L is within the range of 9.3 μm to 10.6 μm. In the following, the pulsed laser beam L will be referred to as laser beam L.

The laser optical element 20 shapes the shape of the laser beam L output from the laser oscillator 10 and outputs it to the processing head 30. The laser optical element 20 adjusts the aperture of the laser beam L output from the laser oscillator 10, and includes a collimating lens 21 that collimates the laser beam L, and a collimator lens 21 that adjusts the aperture of the laser beam L output from the laser oscillator 10, and a collimating lens 21 that collimates the laser beam L. It has a mask hole 22 for cutting out. One to a plurality of collimating lenses 21 are arranged. The shape of the mask hole 22 is usually circular.

The processing head 30 includes

galvano mirrors

31Y and 31X that deflect the laser beam L,

galvano scanners

32Y and 32X that rotationally drive the

galvano mirrors

31Y and 31X, and an fθ lens 33 that is a lens that focuses the laser beam L. have

The galvanometer mirror 31Y reflects the laser beam L incident on the processing head 30. The galvano scanner 32Y is a servo motor used to position the galvano mirror 31Y. The galvano scanner 32Y rotates the galvano mirror 31Y under control according to the position command. That is, the galvano scanner 32Y adjusts the position and angle of the laser beam L incident on the fθ lens 33. Specifically, the galvano scanner 32Y moves the irradiation position of the laser beam L in the Y-axis direction by rotating the galvano mirror 31Y within a specific swing angle range.

The galvano mirror 31X reflects the laser beam L incident from the galvano mirror 31Y. The galvano scanner 32X is a servo motor used to position the galvano mirror 31X. The galvano scanner 32X rotates the galvano mirror 31X under control according to the position command. That is, the galvano scanner 32X adjusts the position and angle of the laser beam L incident on the fθ lens 33. Specifically, the galvano scanner 32X moves the irradiation position of the laser beam L in the X-axis direction by rotating the galvano mirror 31X within a specific swing angle range.

The fθ lens 33 is a lens that focuses the laser beam L reflected by the galvanometer mirror 31X and irradiates the workpiece W with the laser beam L perpendicularly.

The workpiece conveyance table 40 is moved in the X-axis direction or the Y-axis direction by control according to the position command. That is, the workpiece conveyance table 40 has a drive mechanism in the X-axis direction and a drive mechanism in the Y-axis direction. The drive mechanism in the X-axis direction and the drive mechanism in the Y-axis direction are driven in accordance with the position command, so that the workpiece conveyance table 40 can change its position within the XY plane. The movable range of the galvano mirrors 31Y, 31X by driving the

galvano scanners

32Y, 32X, that is, the change in the irradiation position of the laser beam L in the X-axis direction and the Y-axis direction by the galvano mirrors 31Y, 31X is limited to an extremely narrow range. Therefore, it is difficult to drill holes in the entire workpiece W only by changing the irradiation positions of the galvano mirrors 31Y and 31X by driving the

galvano scanners

32Y and 32X. Therefore, after the processing in the movable range of the galvano mirrors 31Y, 31X is completed by driving the

galvano scanners

32Y, 32X, the position of the workpiece W to be processed is changed using the workpiece transfer table 40, and Processing is performed again within the movable range of the galvano mirrors 31Y and 31X. As a result, the entire workpiece W can be drilled.

The laser processing machine 1 further includes a control device 50 that controls the entire laser processing machine 1. The control device 50 controls the operations of the laser oscillator 10, the

galvano scanners

32Y, 32X, the workpiece transfer table 40, and the like. In one example, the control device 50 generates a position command for the work transfer table 40, a laser output command for the laser oscillator 10, and a position command for the

galvano scanners

32Y and 32X. A position command for the workpiece conveyance table 40 is output to a drive mechanism for the workpiece conveyance table 40 in the X-axis direction and the Y-axis direction. The laser output command is output to the laser oscillator 10. Position commands for the

galvano scanners

32Y and 32X are output to the

galvano scanners

32Y and 32X. In addition, below, when the

galvano scanners

32Y and 32X are not distinguished individually, they are called the galvano scanner 32. Further, the galvano mirrors 31Y and 31X are referred to as a galvano mirror 31 unless they are individually distinguished.

Next, the configuration of the galvano scanner 32 will be explained. FIG. 2 is a diagram schematically showing an example of the configuration of the galvano scanner according to the first embodiment. In FIG. 2, a galvano mirror 31 fixed to the galvano scanner 32 is also illustrated. The galvano scanner 32 includes a motor 35 and an electrolytic corrosion suppressing section 37 that suppresses the occurrence of electrolytic corrosion in the

bearings

351 and 352 of the motor 35. Note that, of the two ends of the motor 35 in the direction of the rotation axis of the rotor 340, which will be described later, the end on which the galvanometer mirror 31 is provided is referred to as a first end, and the end on which the electrolytic corrosion suppressing section 37 is provided is referred to as a first end. The end of is called the second end.

The galvanometer mirror 31 is fixed to a shaft 342 of a rotor 340 (described later) of the motor 35 at a first end side of one of the two ends of the motor 35 in the direction of the rotation axis, and rotates around the rotation axis. . The galvanometer mirror 31 includes a mirror 311 and a mirror holder 312. Mirror 311 is fixed to mirror holder 312. The mirror holder 312 is fixed to the shaft 342 of the motor 35 and holds the mirror 311. The mirror 311 reflects the incident laser beam L. The galvanometer mirror 31 rotates in conjunction with the shaft 342 to deflect the laser beam L to an arbitrary angle. Generally, a rotation angle of about ±20 degrees is sufficient for the galvanometer mirror 31.

The motor 35 includes a stator 330, a rotor 340, and a pair of

bearings

351 and 352. Stator 330 is made of a conductive material. Stator 330 includes a housing 331 , an iron core 332 , a coil 333 , and a conductor 334 . The housing portion 331 houses an iron core 332, a coil 333, a rotor 340, and a pair of

bearings

351, 352. The housing portion 331 has a hollow structure that can accommodate the rotor 340 therein. The housing portion 331 is made of a conductive material. The iron core 332 is a cylindrical member for generating torque of the motor 35. The iron core 332 is preferably made of a ferromagnetic material such as iron. The coil 333 is arranged along the inner peripheral surface of the iron core 332 and has a cylindrical shape. A cylindrical coil 333 is arranged inside a cylindrical iron core 332 . The conducting wire 334 is wiring that electrically connects a current amplifier (not shown) to the coil 333, and allows current from the current amplifier to flow through the coil 333. By passing a current through the conducting wire 334, the rotor 340 rotates, making it possible to drive the motor 35.

The rotor 340 is made of a conductive material. The rotor 340 has a permanent magnet 341 and

shafts

342 and 343. The permanent magnet 341 is placed inside the cylindrical coil 333 at a predetermined distance from the coil 333. In one example, the permanent magnet 341 has a cylindrical shape, and different magnetic poles are alternately arranged in the circumferential direction. The permanent magnet 341 is rotatable around the central axis of the cylindrical coil 333. The central axis of the cylindrical coil 333 corresponds to the rotation axis.

Shafts

342 and 343 are connected to both sides of the permanent magnet 341 along the rotation axis. The permanent magnet 341 and the

shafts

342, 343 may be integrally formed, or may be connected by a method such as welding. A galvanometer mirror 31 is fixed to an end of one shaft 342. The other shaft 343 protrudes beyond the end of the housing portion 331 of the stator 330. The

shafts

342 and 343 rotate together with the rotation of the permanent magnet 341, and thereby the galvanometer mirror 31 also rotates around the rotation axis.

The pair of

bearings

351 and 352 rotatably hold the

shafts

342 and 343, respectively, inside the housing portion 331. In one example, the

bearings

351 and 352 are rolling bearings having an outer ring fixed to the housing 331, an inner ring holding the

shafts

342 and 343, and rolling elements held between the inner ring and the outer ring. . An oil film is spread between the inner ring, the outer ring, and the rolling elements. As the permanent magnet 341 of the rotor 340 rotates, the inner ring holding the

shafts

342 and 343 fixed to the permanent magnet 341 rotates about the rotation axis relative to the outer ring fixed to the housing 331. Become. At this time, the rolling elements also rotate.

The electrolytic corrosion suppressing unit 37 is provided on the second end side of the motor 35 in the direction of the rotation axis, the one where the galvanometer mirror 31 is not provided, and electrically connects the stator 330 and the rotor 340. Connect to. Specifically, the electrolytic corrosion suppressing section 37 is provided at the end of the stator 330 on the opposite side from the galvano mirror 31. The electrolytic corrosion suppressing section 37 is a member that electrically connects the stator 330 and the rotor 340, that is, a member that makes the stator 330 and the rotor 340 have the same potential. The electrolytic corrosion suppressing section 37 includes a support structure section 370 that is electrically connected to the stator 330, and a ground structure section 380 that electrically connects the stator 330 and the support structure section 370 to the rotor 340.

The support structure 370 supports the grounding structure 380 at the second end of the stator 330. Specifically, the support structure section 370 is provided at a second end of the stator 330 opposite to the first end where the galvanometer mirror 31 is installed. The support structure portion 370 includes a plate-like member 371 and leg portions 372. The plate member 371 is a plate member disposed perpendicular to the rotation axis and corresponds to the first member. A through hole 371a that supports the grounding structure portion 380 is provided at a position of the plate member 371 that intersects with the rotation axis, which is a virtual straight line. The inner peripheral surface of the through hole 371a is threaded and has a female thread. The leg portion 372 is a member that supports the plate member 371 at the end of the stator 330. The leg portion 372 may be a cylindrical member or may be a rod-like member extending in the direction of the rotation axis. In the latter case, the plate-like member 371 may be supported at the end of the stator 330 by two or more rod-like members. In one example, the leg portion 372 is fixed to the housing portion 331 of the stator 330 by a fixing method such as screws or welding. Further, the leg portion 372 is fixed to the plate member 371 by a fixing method such as screws or welding. The plate member 371 and the leg portions 372 are, for example, made of a conductive material such as stainless steel.

The grounding structure 380 is a member made of a conductive material that contacts the rotor 340 at one end and is supported by the support structure 370 at the other end. In the example of FIG. 2, one end of the grounding structure 380 is disposed in a through hole 371a provided in the plate member 371 of the support structure 370. Specifically, the grounding structure section 380 is arranged such that one end thereof is fixed to the through hole 371a of the plate-like member 371, and the other end thereof contacts the shaft 343 of the rotor 340. The outer peripheral surface of the grounding structure 380 is threaded and has a male thread. By screwing the grounding structure 380 into the through hole 371a, the grounding structure 380 can be fixed to the support structure 370. It is desirable that the grounding structure section 380 has a configuration in which electrical connection with the shaft 343 is maintained even when the shaft 343 rotates. In one example, the grounding structure portion 380 may be a needle-like member or a ball plunger. In one example, the grounding structure portion 380 is made of stainless steel.

FIG. 3 is a sectional view showing an example of the configuration of a grounding structure used in the galvano scanner according to the first embodiment. FIG. 3 shows a case where the grounding structure 380 is a ball plunger. The ground structure section 380 houses a spherical member 381 made of a conductive material, an elastic member 382 arranged in contact with the spherical member 381 and made of a conductive material, and the spherical member 381 and the elastic member 382. , and a housing 383 made of a conductive material. Inside the housing 383, one end of the elastic member 382 is fixed inside the housing 383, and the other end contacts the spherical member 381. The spherical member 381 is not fixed to the elastic member 382, but is only in contact with it. Further, the spherical member 381 comes into contact with the shaft 343 of the rotor 340. As a result, the spherical member 381 rotates in conjunction with the rotation angle of the rotor 340. That is, when the shaft 343 of the rotor 340 that contacts the spherical member 381 rotates, the spherical member 381 also rotates. As a result, smooth rotation of the rotor 340 is realized. The spherical member 381 corresponds to the second member.

Further, the spherical member 381 is movable so as to be in constant contact with the rotor 340. Thereby, the pressing force with which the spherical member 381 pushes the rotor 340 in the direction of the rotation axis can be adjusted. In one example, the spherical member 381 can be pressed against the rotor 340 under the condition that the positional accuracy of the laser beam L reflected by the galvano mirror 31, which is generated by pushing the rotor 340 in the direction of the rotation axis, is not deteriorated. Further, the galvano scanner 32 can be used while ensuring contact reliability between the spherical member 381 and the rotor 340.

Further, even while the spherical member 381 is rotating, the spherical member 381 is in contact with the elastic member 382, so that it can move in the direction of the rotation axis so as to come into contact with the rotor 340. That is, the elastic member 382 contacts the spherical member 381 and presses the spherical member 381 toward the rotor 340. This allows the elastic member 382 to keep the spherical member 381 in contact with the rotor 340 at all times. Electrical contact can be maintained between the spherical member 381 and the elastic member 382, and electrical contact can also be maintained between the rotor 340 and the stator 330 via the ground structure 380 and the support structure 370. becomes.

As described above, the elastic member 382 presses the spherical member 381 with enough force to maintain contact between the spherical member 381 and the rotor 340. The pressing force generated by the displacement of the elastic member 382 does not become large enough to push the rotor 340 of the motor 35 in the direction of the rotation axis and displace the rotor 340 with respect to the stator 330 in the direction of the rotation axis. It is adjusted as follows. The elastic member 382 is, for example, a spring.

The operation of such a galvano scanner 32 will be explained. When a current is applied to the coil 333 according to instructions from the control device 50, the rotor 340 rotates. As the rotor 340 rotates, the galvanometer mirror 31 fixed to the shaft 342 also rotates. At the second end of the motor 35 opposite to the first end where the galvanometer mirror 31 is installed, the grounding structure 380 is in contact with the other shaft 343. That is, rotor 340 and stator 330 are electrically connected via grounding structure 380 and support structure 370, and rotor 340 and stator 330 are at the same potential. Therefore, generation of shaft voltage, which is a potential difference, between the inner and outer rings of the

bearings

351 and 352 due to the influence of eddy currents of the magnets and the like when the galvano scanner 32 is driven is suppressed. In addition, even if the oil film of the

bearings

351 and 352 insulates the inner and outer rings from each other, even if the oil film breaks and the inner and outer rings come into contact, the inner and outer rings will be protected against electrical corrosion. Since they are at the same potential through the portion 37, generation of electric discharge between the inner ring and the outer ring is suppressed. As a result, damage inside the

bearings

351, 352 is suppressed. Since damage inside the

bearings

351, 352 is suppressed, smooth rotation of the

bearings

351, 352 can be continued, and control of the irradiation position of the laser beam L is not adversely affected.

Note that the structure is not limited to the structure shown in FIG. 2 as long as the electrical contact between the rotor 340 and the stator 330 is maintained by the electrolytic corrosion suppressing section 37. In FIG. 2 , the area of the plate member 371 of the electrolytic corrosion suppressing portion 37 in the direction perpendicular to the rotation axis is approximately the same as the area of the stator 330 in the direction perpendicular to the rotation axis. However, if the structure allows the grounding structure 380 to maintain connection with the shaft 343 and the plate-like member 371 to support the grounding structure 380, the area of the plate-like member 371 in the direction perpendicular to the rotation axis is large. The size and shape are not particularly limited.

Furthermore, in order to stabilize the pressing force by the elastic member 382 of the grounding structure 380, it is necessary to firmly determine the position of the casing 383 of the grounding structure 380 in the direction of the rotation axis. For example, even if the grounding structure 380 is fixed to the plate-like member 371 as shown in FIG. It may move. In this way, when the position of the housing 383 in the direction of the rotation axis changes, the fixing position of the elastic member 382 also changes, and the magnitude of the pressing force also changes. In other words, the pressing force exerted by the elastic member 382 becomes unstable. Therefore, the position of the elastic member 382 may be fixed so that the spherical member 381 can always be brought into contact with the rotor 340 with a predetermined pressing force.

FIG. 4 is a diagram schematically showing another example of the configuration of the galvano scanner according to the first embodiment. Components that are the same as those described above are given the same reference numerals, and their explanations will be omitted. In FIG. 4, the length of the grounding structure portion 380a is longer than the thickness of the plate member 371. In FIG. 2, the end of the grounding structure 380 opposite to the motor 35 is located inside the through hole 371a of the plate member 371, but in FIG. 371 through the through hole 371a. Further, the electrolytic corrosion suppressing section 37 in FIG. 4 further includes a nut 385 that is a positioning member that suppresses movement of the grounding structure section 380a in the direction of the rotation axis and determines the fixing position of the elastic member 382. Although not shown, since a thread is cut on the outer peripheral surface of the grounding structure portion 380a as described above, the nut 385 is screwed into the portion protruding from the plate member 371. As a result, movement of the grounding structure portion 380a in the direction of the rotation axis is suppressed, and the fixed position of the elastic member 382 is stabilized. As a result, it becomes possible to keep the spherical member 381 in contact with the rotor 340 at all times with a predetermined pressing force.

FIG. 5 is a diagram schematically showing another example of the configuration of the galvano scanner according to the first embodiment. Components that are the same as those described above are given the same reference numerals, and their explanations will be omitted. In addition to the structure shown in FIG. 2, the electrolytic corrosion suppressing section 37 in FIG. 5 further includes a grounding structure fixing section 390. The grounding structure fixing part 390 is provided on the opposite side of the support structure 370 from the motor 35, and is a member that fixes the grounding structure 380 so that its position in the direction of the rotation axis does not move. The grounding structure fixing portion 390 corresponds to a positioning member. The grounding structure fixing section 390 includes a support structure section 391 and a position fixing section 395.

The support structure portion 391 includes a plate-like member 392 and leg portions 393. The plate member 392 is a plate member arranged perpendicular to the rotation axis. A through hole 392a that supports the position fixing part 395 is provided at a position of the plate member 392 that intersects with the rotation axis, which is a virtual straight line. The through hole 392a is a screw hole, and the inner peripheral surface of the through hole 392a is threaded to form a female thread. The leg portion 393 is a member that supports the plate-like member 392 with the plate-like member 371 of the support structure portion 370. The leg portion 393 may be a cylindrical member or may be a rod-like member extending in the direction of the rotation axis. In the latter case, the plate-shaped member 392 may be supported by the plate-shaped member 371 of the support structure section 370 by two or more rod-shaped members. In one example, the leg portion 393 is fixed to the plate member 371 of the support structure portion 370 by a fixing method such as screws or welding. Further, the leg portion 393 is fixed to the plate member 392 by a fixing method such as screws or welding.

The position fixing part 395 is a member that comes into contact with the end of the grounding structure part 380 at one end and is supported by the support structure part 391 at the other end. In one example, the position fixing part 395 is a member extending in the direction of the rotation axis. In the example of FIG. 5, the position fixing part 395 is arranged such that one end is fixed to the through hole 392a of the plate member 392, and the other end is in contact with the grounding structure part 380. The outer peripheral surface of the position fixing part 395 is threaded and has a male thread. The position fixing part 395 can be fixed to the support structure part 391 by screwing the position fixing part 395 into the through hole 392a. As a result, the grounding structure section 380 is pushed in by the position fixing section 395 from the side opposite to the motor 35. In other words, the position of the grounding structure 380 in the direction of the rotation axis, more specifically, the fixed position of the elastic member 382 is fixed. As a result, it becomes possible to keep the spherical member 381 in contact with the rotor 340 at all times with a predetermined pressing force.

As described above, the galvano scanner 32 of the first embodiment includes a rotor 340 having a permanent magnet 341 that rotates around the rotation axis and

shafts

342 and 343 connected to both sides of the permanent magnet 341 along the rotation axis. A motor 35 with a stator 330 arranged at a defined distance from 340 and

bearings

351, 352 supporting

shafts

342, 343, and a galvanometer mirror in the two ends of the motor 35 in the direction of the axis of rotation. The electrolytic corrosion suppressing portion 37 is provided at the end where the stator 31 is not provided and electrically connects the stator 330 and the rotor 340. As a result, during operation of the galvano scanner 32, the electrolytic corrosion suppressing section 37 electrically connects the stator 330 and the rotor 340, so that the inner and outer rings of the

bearings

351 and 352 have the same potential. Further, the electrolytic corrosion suppressing portion 37 contacts the rotor 340 with a pressing force that maintains contact with the shaft 343 of the rotor 340. Therefore, while suppressing the displacement in the direction of the rotating shaft between the inner and outer rings of the

bearings

351 and 352 compared to the conventional case, the occurrence of electrolytic corrosion between the inner and outer rings of the

bearings

351 and 352 is suppressed. It has the effect of being able to

In addition, in the conventional technology, a thrust force is applied to the rotor shaft by hydraulic pressure until the oil film surrounding the rolling elements of the

bearings

351, 352 breaks and the inner ring, rolling elements, and outer ring are electrically connected, and there is no need for electrical continuity. Thrust force is removed. In other words, control is performed in two ways: ON, which applies thrust force, and OFF, which does not apply thrust force. When such conventional technology is applied to the galvanometer scanner 32 that requires strict positioning accuracy, the rotor 340 is displaced in the direction of the rotation axis when it is on, and the galvano mirror 31 is also displaced in the direction of the rotation axis. Put it away. When such a displacement occurs, the positional accuracy of the laser beam L reflected by the galvano mirror 31 deteriorates. When switching from on to off, the rotor 340 is also displaced in the direction of the rotation axis, and the positional accuracy is similarly deteriorated. On the other hand, in the galvano scanner 32 of the first embodiment, the grounding structure part 380 of the electrolytic corrosion suppressing part 37 only needs to be electrically conductive between the rotor 340 and the stator 330, so it is not necessary to push it in with such strong force. It is sufficient that the contact between the grounding structure 380 and the rotor 340 is maintained at all times. Therefore, the pressing force in the direction of the rotation axis in the first embodiment is weaker than the thrust force in the conventional technology, and does not adversely affect the positional accuracy of the laser beam L reflected by the galvano mirror 31. Furthermore, in the first embodiment, the inner rings, rolling elements, and outer rings of the

bearings

351 and 352 are not actively brought into conduction, and the rolling elements are used in a state surrounded by an oil film. It is possible to suppress the occurrence of electrolytic corrosion between the inner and outer rings of 351 and 352.

Furthermore, as shown in FIGS. 4 and 5, the electrolytic corrosion suppressing section 37 includes a positioning member that fixes the elastic member 382 at a position other than the position where the elastic member 382 in the grounding structure section 380 contacts the spherical member 381. We have made it even more prepared. As a result, the position of the elastic member 382 is fixed, and the pressing force can be stabilized.

The configurations shown in the embodiments above are merely examples, and can be combined with other known techniques, or can be combined with other embodiments, within the scope of the gist. It is also possible to omit or change part of the configuration.

1 Laser processing machine, 10 Laser oscillator, 20 Laser optical element, 21 Collimating lens, 22 Mask hole, 30 Processing head, 31, 31X, 31Y Galvano mirror, 32, 32X, 32Y Galvano scanner, 33 fθ lens, 35 Motor, 37 Electrolytic corrosion suppression unit, 40 workpiece transfer table, 50 control device, 311 mirror, 312 mirror holder, 330 stator, 331 casing, 332 iron core, 333 coil, 334 conducting wire, 340 rotor, 341 permanent magnet, 342, 343 shaft, 351, 352 Bearing, 370, 391 Support structure, 371, 392 Plate member, 371a, 392a Through hole, 372, 393 Leg, 380, 380a Ground structure, 381 Spherical member, 382 Elastic member, 383 Housing, 385 Nut, 390 Grounding structure fixing part, 395 Position fixing part, L Laser beam, W Workpiece.

Claims

a motor having a rotor having a permanent magnet rotating about an axis of rotation and a shaft connected to both sides of the permanent magnet along the axis of rotation, and a stator disposed at a predetermined distance from the rotor;
an electrolytic corrosion suppressing section that is provided at the end where the galvanometer mirror is not provided of the two ends of the motor in the direction of the rotation axis, and electrically connects the stator and the rotor;
A galvano scanner characterized by comprising:
The electrolytic corrosion suppressing part is
a grounding structure that comes into contact with the rotor;
a support structure that supports the grounding structure at an end of the stator;
has
The galvano scanner according to claim 1, wherein the ground structure and the support structure are made of a conductive material.
The support structure includes a first member provided with a through hole on an extension of the rotation axis,
The galvano scanner according to claim 2, wherein the grounding structure is disposed in the through hole.
The galvano scanner according to claim 3, wherein the grounding structure includes a second member that comes into contact with the rotor.
The galvano scanner according to claim 4, wherein the second member is movable in the direction of the rotation axis so as to come into contact with the rotor.
The galvano scanner according to claim 5, wherein the grounding structure further includes an elastic member that contacts the second member and presses the second member toward the rotor.
The galvano scanner according to claim 6, wherein the grounding structure is fixed to the support structure.
The galvano scanner according to claim 7, wherein the electrolytic corrosion suppressing section further includes a positioning member that fixes the elastic member at a position other than the position where it contacts the second member.
a laser oscillator that emits a laser beam;
a lens that focuses the laser beam and irradiates the laser beam onto the processing object;
The galvano scanner according to any one of claims 1 to 8, which adjusts the position and angle of incidence of the laser beam on the lens;
Of the two ends of the motor in the direction of the rotation axis of the galvano scanner, the end that is not provided with the electrolytic corrosion suppressing part is fixed to the shaft and rotates about the rotation axis. Galvano mirror and
A laser processing machine characterized by comprising: