Lens linear motion mechanism, galvanometer scanner, laser cutting machine, and method for manufacturing lens linear motion mechanism

Abstract

Provided are: a lens linear motion mechanism having high dynamic characteristics at low cost and with good assemblability; a galvanometer scanner provided with the lens mechanism; a laser cutting machine provided with the galvanometer scanner; and a method for manufacturing the lens linear motion mechanism. The lens linear motion mechanism includes: a motor; a pulley connected to a rotary shaft of the motor; a belt engaged with the pulley; a lens that is moved linearly as the belt operates; and a tension adjustment structure that adjusts and maintains the tension applied to the belt at a constant value.

Description

Lens linear motion mechanism, galvano scanner, laser processing machine, and method for manufacturing lens linear motion mechanism

[0001] The present disclosure relates to a lens linear motion mechanism, a galvano scanner provided with the lens linear motion mechanism, a laser processing machine provided with the galvano scanner, and a method for manufacturing the lens linear motion mechanism.

[0002] As an example of a linear motion mechanism that converts rotational motion of a motor into linear motion, a known configuration has a belt wound around a pulley connected to the rotating shaft of the motor, with both ends of the belt fixed to a carriage or the like.

[0003] Such linear motion mechanisms are used in various applications, and as one example, a linear motion mechanism for moving a lens in the optical axis direction is known.

[0004] Japanese Utility Model Laid-Open No. 2-69326, Japanese Patent Laid-Open No. 62-188633, Japanese Patent Laid-Open No. 1-116970

[0005] When a linear motion mechanism having a belt and a pulley is used as the linear motion mechanism for a lens of a laser processing scanner or the like, it is required to move and position the lens at high speed and with high accuracy, which requires applying appropriate tension to the belt. As an example of a technique for applying a desired tension to the belt, it is known that a spring such as a leaf spring is incorporated in the pulley, and the elastic force of the spring is used to apply tension to the belt. However, when a spring is used, vibration corresponding to the spring constant may occur and the dynamic characteristics may deteriorate.

[0006] As a technique for applying tension to the belt without using a spring, there is a method of fixing the belt to a belt holder or the like while the belt is stretched during assembly of the linear motion mechanism. However, in this method, since no spring is used, high dynamic characteristics can be obtained, but at the same time, a means or the like for maintaining the belt in a stretched state during assembly is required, leading to problems of high manufacturing cost and poor assemblability.

[0007] Accordingly, a lens linear motion mechanism that has low cost, good assemblability, and high dynamic characteristics is desired.

[0008] One aspect of the present disclosure is a lens linear motion mechanism comprising a motor, a pulley connected to the rotating shaft of the motor, a belt engaged with the pulley, a lens that moves linearly in conjunction with the movement of the belt, and a tension adjustment structure that adjusts the tension applied to the belt to maintain it at a constant value.

[0009] Another aspect of this disclosure is a galvanoscanner having the lens linear motion mechanism described above.

[0010] Further other aspects of this disclosure are laser processing machines having the galvanoscanner described above.

[0011] Another further aspect of the present disclosure is a method for manufacturing the lens linear motion mechanism, comprising the steps of: engaging the belt with the pulley; fixing the belt to a belt holder; displacing and fixing the second member relative to the first member so that a predetermined tension is applied to the belt; fixing the belt to the first member; and removing the second member.

[0012] This is a schematic diagram of a robot including a lens linear motion mechanism according to an embodiment. This is a perspective view showing one example of the lens linear motion mechanism. This is a perspective view showing a pulley and a belt holder. This is a perspective view showing a belt and a belt holder. This is a view of the pulley and belt holder of Figure 3 from a different angle. This is a schematic diagram showing a pulley and a belt holder according to a comparative example. This is a perspective view showing a modified pulley. This is a perspective view showing an example of a belt that can be wound around the pulley of Figure 7. This is a perspective view showing a modified pulley.

[0013] Figure 1 is a schematic perspective view of a laser processing machine 2 including a lens linear motion mechanism according to a preferred embodiment. The laser processing machine 2 includes a robot 4, a galvanometer scanner 6 mounted on the robot 4, a laser light source 8 that supplies laser light to the galvanometer scanner 6, and a laser control device 10 that is wired or wirelessly connected to the galvanometer scanner 6 and the laser light source 8 and controls the galvanometer scanner 6 and the laser light source 8.

[0014] Robot 4 is, for example, an industrial articulated robot, equipped with a movable part (robot arm) 12, and the galvanoscanner 6 is provided at the tip of the movable part 12. In this embodiment, robot 4 is a vertical articulated robot having six drive axes, but the disclosure is not limited thereto, and any robot capable of changing its position and orientation by any mechanism can be used. The operation of robot 4 is controlled by a robot control device 14 connected to robot 4 by wire or wireless. In the illustrated example, the laser control device 10 and the robot control device 14 are separate devices each having a processor and memory, etc., but it is also possible to configure both control devices as a substantially integrated device.

[0015] The galvanometer scanner 6 includes a lens linear motion mechanism 18 for adjusting the focal position of the laser beam 16 from the laser light source 8 in the optical axis direction, and a laser deflection mechanism 20 for changing the direction of the laser beam 16 from the lens linear motion mechanism 18. The lens linear motion mechanism 18 includes a lens drive motor 22 and a lens 24 that is linearly moved by the motor 22, the specific structure of which will be described later.

[0016] The laser deflection mechanism 20 has at least one galvanometer mirror, and in the illustrated example, it has a first galvanometer mirror 28 connected to the rotation axis of the first galvanometer motor 26 and a second galvanometer mirror 32 connected to the rotation axis of the second galvanometer motor 30, with the rotation axes of the first galvanometer motor 26 and the second galvanometer motor 30 being perpendicular to each other. The galvanometer scanner 6 may also optionally have at least one (two in the illustrated example) lens 34 and at least one (one in the illustrated example) mirror 36. The galvanometer scanner 6 configured in this way can irradiate the laser beam 16 from the laser light source 8 to a predetermined position on the workpiece 38, which is the object to be laser processed, and even if the workpiece 38 is displaced as shown by the dashed line, the focal length of the laser beam 16 can be appropriately adjusted by appropriately displacing the lens 24 in the lens linear motion mechanism 18.

[0017] Figure 2 is a perspective view showing an example configuration of the lens linear motion mechanism 18. The lens linear motion mechanism 18 includes a motor 22, a stage 40, a motor holder 42 attached to the stage 40 that holds the motor 22 so that the rotation axis of the motor 22 is perpendicular to the upper surface of the stage 40, a pulley 44 (see Figure 3, later described later) connected to the rotation axis 23 of the motor 22 (see Figure 5, later described later), a belt 46 (see Figure 4, later described later) that engages with the pulley 44, a belt holder 48 that holds the belt 46, a linear guide 50 fixed to the upper surface of the stage 40 and supporting the belt holder 48 so that the belt holder 48 can move linearly relative to the stage 40, a lens holder 52 fixed to the belt holder 48 and supported so as to be able to move linearly by the linear guide 50, and a lens 24 fixed to the lens holder 52.

[0018] Figure 3 is an exploded perspective view showing a first embodiment of the main part of the lens linear motion mechanism 18. The pulley 44 has a generally fan-shaped form, but has a structure that allows it to be divided into at least two members, and has means to make the position of one member variable relative to the position of the other member, and to fix the relative positions of the two members. In the illustrated example, the pulley 44 has an arc-shaped curved surface 54 and a receiving hole 56 that receives the rotation axis (shaft) 23 of the motor 22 (see Figure 5), and has a first member 58 that rotates in conjunction with the operation of the motor 22, and a second member 62 that is positioned opposite the first member 58 on the surface 60 opposite to the curved surface 54 with respect to the receiving hole 56. The first member 58 may have an opening 64 between the curved surface 54 and the receiving hole 56 in order to reduce its weight.

[0019] The surface 60 of the first member 58 is provided with at least one, preferably a plurality (two in the illustrated example), positioning pins 66, while the second member 62 has guide holes 68 into which the positioning pins 66 can be inserted. The second member 62 also has tapped holes 70 that penetrate through the second member 62, and screws 72 such as grub screws 72 are inserted through the tapped holes 70.

[0020] The axial direction of the positioning pin 66 and the axial direction of the tapped hole 70 are approximately equal. Therefore, when the screw 72 is screwed into the tapped hole 70 with the second member 62 in contact with the surface 60 of the first member 58, the tip of the screw 72 comes into contact with the surface 60 of the first member 58, and further screwing in the screw 72 causes the second member 62 to be displaced away from the first member 58. In this way, the distance between the second member 62 and the first member 58 can be adjusted, and as a result, a tension adjustment structure can be realized that adjusts the tension on the belt 46, which engages with both the first member 58 and the second member 62, to an appropriate value and maintains that value. Furthermore, because the screw 72 is used, the second member 62 does not undergo elastic displacement relative to the first member 58, so the adjusted position of the second member 62 relative to the first member 58 is fixed and does not change when the laser processing machine 2 is in use. With this tension adjustment structure, the galvanoscanner 6, including the lens linear motion mechanism 18, has high frequency response characteristics.

[0021] Figure 4 shows an example of the configuration of a belt 46 that engages with a pulley 44, and Figure 5 is a schematic top view of the pulley 44, belt 46, and belt holder 48. The belt 46 is, for example, a steel belt, and is wound around the pulley 44 (not shown in Figure 4) in a so-called α-winding manner, engaging with both the first member 58 and the second member 62. Both ends of the belt 46 are fixed to the belt holder 48 by fastening means such as bolts 74. The belt 46 also has holes 76 through which the aforementioned screws 72 can be inserted. The tension of the belt 46 having such a configuration can be set and maintained to an appropriate value by adjusting and fixing the position of the second member 62 relative to the first member 58, as described above.

[0022] Figure 6 shows another method for applying appropriate tension to a belt as a comparative example. First, the belt 146 is wound around the pulley 144 in an α-winding manner or the like, and weights 182 are attached to both ends of the belt 146. Next, a pulley 184 or the like is used to ensure that the force from the weights 182 acting in the direction of gravity 186 acts horizontally on the belt 146. Next, from this state, the belt 146 is fixed to the belt holder 148 using fastening means such as bolts 174. Finally, the belt 146 is cut using cutting means such as scissors 188.

[0023] The method shown in Figure 6 allows the belt 146 to be fixed with appropriate tension, but it requires work such as fixing and cutting the belt 146 while applying tension to it with a weight 182 or the like. This results in a large-scale setup for assembling the lens linear motion mechanism and the waste of a considerable length of belt.

[0024] On the other hand, in the first embodiment of this disclosure, after the belt 46 is wound around the pulley 44 and fixed to the belt holder 48, the tension of the belt 46 can be adjusted by displacing the second member 62 relative to the first member 58. Therefore, in the first embodiment, the rigidity (dynamic characteristics) of the lens linear motion mechanism 18 can be ensured while its assembly and belt tension can be easily adjusted.

[0025] Figure 7-9 shows a second embodiment of the main part of the lens linear motion mechanism 18. Components that can be the same as in the first embodiment are given the same reference numerals as in the first embodiment, and detailed explanations are omitted.

[0026] In the second embodiment, the first member 58a and the belt 46a of the pulley 44a have tapped holes 78 and holes 80, respectively, allowing the belt 46a to be fixed to the first member 58a. This differs from the first embodiment, however other components may be the same as in the first embodiment. Specifically, the first member 58a has tapped holes 78 in parts other than the arc-shaped curved surface 54 and the surface 60 facing the second member 62, while the belt 46a has holes 80 at positions facing the holes 78 when wound around the first member 58a. In this way, the belt 46a can be fixed to the first member 58a by inserting bolts or the like (not shown) into the tapped holes 78.

[0027] In the second embodiment, by utilizing the tapped holes 78 and 80, the belt 46a can be fixed to the first member 58a with appropriate tension applied. Therefore, after fixing the belt 46a to the first member 58a, the second member 62 is unnecessary. Furthermore, without the second member 62, the pulley 44a is lighter by the weight of the second member 62, further reducing inertia and improving the operational performance of the lens linear motion mechanism 18.

[0028] Therefore, the manufacturing method for the lens linear motion mechanism according to the second embodiment may include the steps of engaging the belt 46a with the pulley 44a, fixing the belt 46a to the belt holder 48, displacing and fixing the second member 62 relative to the first member 58a so that a predetermined tension is applied to the belt 46a, fixing the belt 46a to the first member 58a, and removing the second member 62. In order to remove the second member 62, the belt 46a may be cut at an appropriate part. With such a manufacturing method, a lens linear motion mechanism is ultimately provided in which the belt 46a is given appropriate tension without having the second member 62.

[0029] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0030] The following additional information is disclosed regarding the above embodiments and modifications.

[0031] (Note 1) A lens linear motion mechanism comprising a motor, a pulley connected to the rotating shaft of the motor, a belt engaged with the pulley, a lens that moves linearly in conjunction with the movement of the belt, and a tension adjustment structure that adjusts the tension applied to the belt to maintain it at a constant value.

[0032] (Note 2) The lens linear motion mechanism according to Note 1, wherein the pulley has a first member connected to the rotating shaft of the motor and a second member configured to be displaceable relative to the first member, and the belt engages with both the first member and the second member.

[0033] (Note 3) The lens linear motion mechanism according to Note 2, wherein the tension adjustment structure has a tapped hole formed in the second member and a screw that is screwed into the tapped hole and can contact the first member.

[0034] (Note 4) The lens linear motion mechanism according to Note 2 or 3, wherein the belt is fixed to the first member.

[0035] (Note 5) A galvanometer scanner having a lens direct motion mechanism as described in any one of Notes 1 to 3.

[0036] (Note 6) A laser processing machine equipped with the galvanometer scanner described in Note 5.

[0037] (Note 7) A method for manufacturing a lens linear motion mechanism as described in Note 2, comprising the steps of: engaging the belt with the pulley; fixing the belt to a belt holder; displacing and fixing the second member relative to the first member so that a predetermined tension is applied to the belt; fixing the belt to the first member; and removing the second member.

[0038] 2 Laser processing machine 4 Robot 6 Galvanometer scanner 8 Laser light source 10 Laser control device 12 Robot arm 14 Robot control device 16 Laser beam 18 Lens linear motion mechanism 20 Laser deflection mechanism 22 Lens drive motor 24, 34 Lens 26, 30 Galvanometer motor 28, 32 Galvanometer mirror 36 Mirror 38 Workpiece 40 Stage 42 Motor holder 44 Pulley 46, 46a Belt 48 Belt holder 50 Linear guide 52 Lens holder 54 Curved surface 56 Receiving hole 58, 58a First member 60 Surface 62 Second member 64 Opening 66 Positioning pin 68 Guide hole 70, 78 Tapped hole 72 Grub screw 74 Bolt 80 Hole

Claims

1. A lens linear motion mechanism comprising: a motor; a pulley connected to the rotating shaft of the motor; a belt engaged with the pulley; a lens that moves linearly in conjunction with the movement of the belt; and a tension adjustment structure that adjusts the tension applied to the belt to maintain it at a constant value.

2. The lens linear motion mechanism according to claim 1, wherein the pulley has a first member connected to the rotating shaft of the motor and a second member configured to be displaceable relative to the first member, and the belt engages with both the first member and the second member.

3. The lens linear motion mechanism according to claim 2, wherein the tension adjustment structure comprises a tapped hole formed in the second member and a screw that is screwed into the tapped hole and can contact the first member.

4. The lens linear motion mechanism according to claim 2 or 3, wherein the belt is fixed to the first member.

5. A galvanoscanner having a lens linear motion mechanism according to any one of claims 1 to 3.

6. A laser processing machine having a galvanometer scanner as described in claim 5.

7. A method for manufacturing a lens linear motion mechanism according to claim 2, comprising: engaging the belt with the pulley; fixing the belt to a belt holder; displacing and fixing the second member relative to the first member so that a predetermined tension is applied to the belt; fixing the belt to the first member; and removing the second member.

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