JP2002006255A - Scanner and laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanner capable of improving machining accuracy by reducing the amplitude of the vibration of a mirror at the time of positioning the mirror. SOLUTION: A mirror mounter 2 holding the mirror 1 is fixed on a rotor 5 by a mounter fixing jig 3 and a mounter fixing screw 4. Weight screws 7 are screwed in two directions orthogonal to the axial center O of the rotation of the mounter 2. By turning the screw 7 in/out of the mounter 2, a position where the amplitude of the vibration of the mirror 1 becomes small in the case of stopping the mirror 1 is obtained and the screw 7 is positioned at the obtained position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner (such as a galvanometer) for positioning a rotatably supported shaft in a rotational direction, a scanner holding a mirror on the shaft, and laser processing for positioning a laser beam by the scanner. About the machine.

[0002]

2. Description of the Related Art In a laser processing machine such as a laser drilling machine or a laser marker for processing a hole in a printed circuit board, a laser oscillator is fixed, and a laser beam is reflected by a mirror which can be freely positioned and is emitted to a target position. Since the positioning accuracy of the mirror directly affects the processing accuracy, the mirror is held by, for example, a scanner provided with a capacitance type angle sensor having a high positioning speed and excellent position accuracy.

FIGS. 6A and 6B show a conventional scanner in which a mirror is held on a shaft. FIG. 6A is a front sectional view, and FIG. 6B is a sectional view taken along line KK in FIG. The rotor 5 disposed at the center of the scanner 6 has a rotating shaft 5a and a rotating shaft 5a.
And an integral coil 5b, and is rotatable by a pair of bearings 14 supported by a case 13. The angle sensor 16 includes a dielectric 16a and a pair of electrode plates 16b. The dielectric 16a is fixed to the rotor 5, and the electrode plate 16b is fixed to the case 13 with the dielectric 16a interposed therebetween. The mirror 1 is fixed to the mirror mounter 2 arranged at the end of the rotor 5. A pair of permanent magnets 15 is provided on the inner surface of the case 13 at a position facing the coil 5b.
Are arranged with the N pole and the S pole facing each other.

Next, the operation of the conventional scanner will be described.
The scanner controller (not shown) to which the target angle signal is input supplies a drive current of a value corresponding to the input signal to the coil 5b. Then, due to the electromagnetic interaction between the magnetic field formed by the permanent magnet 15 and the current flowing in the coil 5b, a torque proportional to the current is generated in the coil 5b, and the rotor 5 rotates. The scanner controller detects the rotation angle of the rotor 5 with the angle sensor 16 and corrects the position if the angle is out of the target angle, thereby positioning the mirror 1 at the target angle with high accuracy.

In a laser drilling machine and a laser marker, since processing is performed after positioning a laser beam, it is required not only to move a mirror to a target position at a high speed but also to stop at a position where the mirror is reached in a short time. Therefore, Japanese Patent Application Laid-Open
In JP-A-55500 and JP-A-9-222579, the rotor 5 and the mirror 1 are positioned with high precision by an electric control technique.

[0006]

However, when the rotor 5 is stopped at the target position, a large vibration may be generated in the mirror. If processing is performed in a state where the mirror is vibrating, the irradiation position of the laser beam shifts, and the processing accuracy decreases. Also, as the positioning speed of the scanner is increased, the vibration of the mirror tends to increase, which is an obstacle to speeding up.

[0007] The present inventors have found that the vibration generated in the mirror is
A member that is supported and rotated by the bearing 14, which has not been considered as a problem in the related art, that is, an assembly including the rotor 5, the mirror mounter 2, the mirror 1, and the like (hereinafter, referred to as a rotating part R).
Was found to be caused by an imbalance in the direction perpendicular to the rotation axis O (particularly, imbalance of the rotor). Hereinafter, the behavior of the rotating unit R at the time of step response, that is, when the rotating unit R is suddenly stopped will be described with reference to a model diagram.

FIG. 7A is a diagram schematically illustrating the rotating part R. For example, assume that an unbalanced mass a exists at a point a of the coil 5b. Since the angular acceleration when the rotating unit R stops is in the opposite direction to the rotation direction, when the rotating unit R stops, an inertial force is generated in each part of the rotating unit R in the direction in which the rotation continues.
In a portion symmetrical with respect to the axis O of rotation, an inertia force having the same magnitude acts on the left and right sides of the axis O and acts in the opposite direction, so that it becomes a couple. However, there is no object to be balanced with respect to the unbalanced mass a, so an inertial force A is generated around the axis O. Then, the generated inertial force A strikes the rotating shaft 5a as a translational force in a direction orthogonal to the axis O, whereby
As shown in (b), a primary bending vibration is generated on the rotating shaft 5a. Then, as the rotating part R is rotated at a higher speed, the inertia force A increases, the bending of the rotating shaft 5 increases, that is, the amplitude of the vibration increases, and the time until the mirror 1 stands still increases. Here, the same phenomenon as described above occurs when the unbalanced mass a exists in the mirror 1 and the rotating shaft 5a.

If the rotating part R is balanced, the mirror 1
Vibration can be prevented. However, even when the rotor 5 and the mirror 1 are individually balanced, relative displacement easily occurs when the mirror 1 is held by the rotor 5, and it is difficult to obtain a balanced rotating portion R. It is.

An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a scanner which can reduce the amplitude of vibration of a mirror at the time of mirror positioning and can improve the processing accuracy.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a scanner for positioning a rotatably supported shaft in the rotational direction, in order to correct imbalance in a direction perpendicular to the axis of rotation. Equipment is provided.

The scanner may be one in which a mirror is arranged on a shaft, and the device for correcting imbalance may be an eccentric member which can be positioned in the rotation direction with respect to the weight or the shaft. In the case of using a mirror, the mirror may be configured to be relatively movable in a direction perpendicular to the axis.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is an external view of a scanner according to a first embodiment of the present invention, in which components having the same functions or the same functions as those in FIG. A mirror mounter 2 holding the mirror 1 is fixed to a rotor 5 by a mounter fixing jig 3 and a mounter fixing screw 4. In two orthogonal directions of the mirror mounter 2,
The weight screw 7 is screwed.

Next, the operation of the weight screw 7 will be described with reference to FIG. Usually, the rotating part R has an unbalanced mass. Here, similarly to the case of FIG. 7, when there is an unbalance mass a at the point a of the coil 5b, as shown in FIG. 7A, the unbalance mass is at the point b on the same side as the point a with respect to the axis O. When the mass b is added, the amplitude of the vibration at the tip of the rotor 5 decreases as shown in FIG. On the other hand, when the unbalance mass c is added to the point c opposite to the point a with respect to the axis O, the amplitude at the tip of the rotor 5 increases as shown in (c).

When the weight screw 7 is moved in and out of the mirror mounter 2, the position of the center of gravity of the weight screw 7 with respect to the axis O changes. Then, after fixing the mirror 1 to the rotor 5, the position of the weight screw 7 is changed little by little, and the scanner is operated at each position to measure the amplitude of the vibration of the mirror 1. Then, the weight screw 7 is positioned at a position where the amplitude of the vibration of the mirror 1 is within the allowable value.

In this embodiment, the weight screw 7
Although a screw is provided on the outer periphery of the mirror mount and screw-coupled to the mirror mounter 2, the weight screw 7 may be a weight, for example, may be replaced with a pin. However, when the weight screw 7 is a pin, it is necessary to facilitate positioning.

Although the weight screws 7 are arranged in two directions at right angles, they may be arranged in only one direction.

When the rotating part R starts rotating,
As in the case of the stop, vibration occurs in the mirror 1. However, if the rotating portion R is balanced in the above procedure, the amplitude of the vibration of the mirror 1 at the start of rotation can be reduced.

FIG. 2 is an external view of a scanner showing a second embodiment according to the present invention, and the same or equivalent parts as those in FIG. 1 are denoted by the same reference numerals. A groove 2 s perpendicular to the axis O is provided at the tip of the mirror mounter 2, and a protrusion 8 p fitted to the groove 2 s is provided at the mounter slider 8 holding the mirror 1.
And the mounter slider 8 is mounted on the mirror mounter 2.
Is configured to be movable in a direction orthogonal to the axis O with respect to. Then, the mirror mounter 2 can be fixed to an arbitrary position of the mounter slider 8 by the fixing screw 9.

In the second embodiment, similarly to the first embodiment, when the mounter slider 8 is moved relative to the mirror mounter 2 and properly positioned,
The rotating portion R can be balanced, and the amplitude of the vibration of the mirror 1 when stopped can be reduced.

FIG. 3 is an external view of a scanner showing a third embodiment according to the present invention, and the same or equivalent parts as those in FIG. 1 are denoted by the same reference numerals. A hole 10a provided in the center of the ring 10 is fitted to the rotating shaft 5a with a slight gap therebetween,
Weight screws 7 are screwed in two orthogonal directions of the ring 10. The ring 10 is positioned on the rotating shaft 5a by a screw (not shown).

In the case of the third embodiment, similarly to the case of the first embodiment, by appropriately positioning the weight screw 7, the rotating portion R can be balanced, and the mirror at the time of stoppage can be adjusted. 1 can reduce the amplitude of the vibration.

As described above, when the ring 10 is provided, the vibration of the mirror 1 can be suppressed even when the screw hole for screwing the weight screw 7 cannot be provided in the mirror mounter 2.

In this embodiment, the ring 10 is fitted on the rotary shaft 5, but they may be screwed together. Further, the ring 10 may be arranged on the mirror mounter 2.

FIG. 4 is an external view of a scanner showing a fourth embodiment according to the present invention, and the same or equivalent parts as those in FIG. 3 are denoted by the same reference numerals. A hole 11a provided in the center of the cylindrical eccentric ring 11 is fitted to the rotating shaft 5a with a slight gap therebetween, and is fixed to the rotating shaft 5a by a fixing screw 12. The axis of the hole 11a is parallel to the axis of the outer peripheral surface and at a position deviated from the axis of the outer peripheral surface.

In the case of the fourth embodiment, the eccentric ring 1
By rotating the mirror 1 around the rotating shaft 5a and positioning it appropriately, the rotating part R can be balanced, and the amplitude of the vibration of the mirror 1 when stopped can be reduced.

As described above, when the eccentric ring 11 is provided,
As in the third embodiment, even when the mirror mounter 2 cannot be provided with a screw hole to be screwed to the weight screw 7, the amplitude of the vibration of the mirror 1 can be reduced.

The eccentric ring 11 may be arranged on the mirror mounter 2.

In each of the above embodiments, the device for correcting the unbalance mass in the rotational direction is provided on the rotor 5 or the mirror mounter 2, but such a device may be provided on the mirror 1.

Although the case where the unbalanced mass exists in the rotor 5 has been described, when the rotating part R can be balanced, the unbalanced mass existing in other components of the rotating part R is also corrected. It goes without saying that it is completed.

When the scanner to which the present invention is applied is applied to a laser beam machine, even if the mirror is positioned at a high speed, the amplitude of the vibration of the mirror when the positioning is completed is small. Can be.

[0032]

As described above, according to the present invention,
In the scanner that positions the rotatably supported shaft in the rotation direction, a device is provided to correct the imbalance in the direction perpendicular to the axis of rotation. The amplitude of the vibration of the shaft or the mirror held on the shaft can be reduced.

[Brief description of the drawings]

FIG. 1 is an external view of a scanner according to a first embodiment of the present invention.

FIG. 2 is an external view of a scanner according to a second embodiment of the present invention.

FIG. 3 is an external view of a scanner according to a third embodiment of the present invention.

FIG. 4 is an external view of a scanner according to a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating the operation of the weight according to the present invention.

FIG. 6 is a diagram showing a conventional scanner holding a mirror on an axis.

FIG. 7 is a diagram illustrating the operation of a conventional scanner.

[Explanation of symbols]

 Reference Signs List 1 mirror 2 mirror mounter 3 mounter fixing jig 4 mounter fixing screw 5 rotor 7 weight screw O axis of rotation

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Miyako Okubo 2100 Kamiimaizumi, Ebina-shi, Kanagawa Prefecture Inside Hitachi Biomechanics Co., Ltd. (72) Inventor Tetsuo Murakami 2100 Kamiimaizumi, Ebina-shi, Kanagawa Prefecture Hitachi Biomechanics Co., Ltd. In-house (72) Inventor Masahiro Oishi 2100 Kamiimaizumi, Ebina-shi, Kanagawa Prefecture Inside Hitachi Via Mechanics Co., Ltd. (72) Inventor Fumio Watanabe 2100 Kami-Imaizumi, Ebina-shi, Kanagawa Prefecture Inside Hitachi Biamechanics Co., Ltd. (72) Person Soichi Toyama 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (72) Inventor Haruaki Otsuki 502-Kantachi-cho, Tsuchiura-city, Ibaraki Pref.Mechanical Research Laboratory, Hitachi, Ltd. F-term (reference) 2H041 AA12 AB14 AC04 AZ01 2H045 AB10 DA02 4E068 CA09 CB05 CD12

Claims (6)

[Claims] 1. A scanner for positioning a rotatably supported shaft in a rotation direction, wherein the scanner is provided with a device for correcting imbalance in a direction perpendicular to the axis of rotation. 2. The scanner according to claim 1, wherein a mirror is held on the shaft. 3. The scanner according to claim 1, wherein the device is a weight. 4. The scanner according to claim 1, wherein the device is an eccentric member that engages with the shaft, and is rotatable with respect to the axis. 5. The scanner according to claim 2, wherein the mirror is relatively movable in a direction perpendicular to the axis with respect to the axis. 6. A laser beam machine in which a laser beam is positioned by a scanner, wherein the laser beam is positioned by the scanner according to claim 1.