End effector for robot

Abstract

To suppress generation of unevenness in processing accuracy while enhancing responsiveness.SOLUTION: An end effector for a robot includes: a fixed unit 50 fixed to a perpendicular articulated robot; a movable unit 60 movable in an axial direction of a rotation axis 64 to the fixed unit 50 together with the rotation axis 64; and first and second voice coil motors VCM1, VCM2 having a permanent magnet MG1 or MG6 and first and second coils CL1, CL2, and moving the movable unit 60. The fixed unit 50 is provided with first and second fixed base side wall parts 56, 57 which are oppositely arranged across the rotation axis 64, and to which the permanent magnet MG1 or MG6 is fixed. The movable unit 60 is provided with first and second movable base side wall parts 67, 68 which are oppositely arranged across the rotation axis 64, and face the first and second fixed base side wall parts 56, 57, and to which the first and second coils CL1, CL2 are fixed.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an end effector attached to a robot. [Background technology]

[0002] For example, Patent Document 1 describes a polishing apparatus for polishing the surface of a wafer, which serves as an object to be polished. The polishing apparatus described in Patent Document 1 includes a polishing head that is movable in the X, Y, and Z directions on a base, and the polishing head is rotationally driven by a spindle. A head housing that forms the polishing head contains a counter-pressure device (air cylinder) that can adjust the pressing force of the polishing member against the wafer by supplying and discharging air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-105103 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 has the problem that the pressure of the polishing member (polishing head) pressing against the wafer is adjusted by controlling the pressure of air, which is a compressible fluid, resulting in low responsiveness and a tendency for variations in processing accuracy.

[0005] An object of the present invention is to provide an end effector for a robot that can improve responsiveness while suppressing variations in machining accuracy. [Means for solving the problem]

[0006] In one aspect of a robot end effector, the robot end effector has a rotational shaft that rotates a rotary tool, and includes a fixed member fixed to the robot, a movable member that is movable in the axial direction of the rotational shaft together with the rotational shaft relative to the fixed member, and a pair of electric motors having a stator and a movable member that move the movable member relative to the fixed member, wherein the fixed member has a pair of fixed wall portions that are arranged opposite each other across the rotational shaft and to which the stators are respectively fixed, and the movable member has a pair of movable wall portions that are arranged opposite each other across the rotational shaft, that face each of the pair of fixed wall portions, and to which the movable members are respectively fixed. [Effects of the Invention]

[0007] According to the present invention, it is possible to realize an end effector for a robot that can improve responsiveness while suppressing variations in machining accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a vertical articulated robot equipped with a polishing module. [Figure 2] 1A and 1B are views of a polishing module alone as viewed from three directions. [Figure 3] FIG. 2 is a perspective view of the polishing module (without cover) as viewed from the drive motor side. [Figure 4] FIG. 2 is a perspective view of the polishing module (without cover) viewed from the polishing pad side. [Figure 5] 3 is a cross-sectional view (without cover) taken along line AA in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 7] FIG. 2 is a perspective view showing the periphery of a power connector of the fixed unit. [Figure 8] FIG. 2 is a perspective view showing the periphery of an encoder of the fixed unit. [Figure 9] FIG. 2 is a perspective view showing the coil side of the movable unit. [Figure 10]FIG. 2 is a perspective view showing the movable rail side of the movable unit. [Figure 11] FIG. 4 is an explanatory diagram of the operation of the voice coil motor. [Figure 12] FIG. 10 is a diagram illustrating the operation of the polishing module (without cover). DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings.

[0010] <Polishing equipment> 1, the polishing apparatus 10 is an industrial machine that polishes the surface of a workpiece 11 (shaded in the figure). Specifically, the polishing apparatus 10 includes a vertical articulated robot 20 and a polishing module 40 attached to the tip of the arm of the vertical articulated robot 20. A workbench 12 is installed in front of the vertical articulated robot 20 and the polishing module 40, on which the workpiece 11 is placed.

[0011] A control unit 13 is electrically connected to the vertical articulated robot 20, and the control unit 13 controls the vertical articulated robot 20 in accordance with a polishing operation program input in advance. Specifically, the control unit 13 can accurately position the polishing module 40 (polishing pad 15) relative to the workpiece 11 based on three-dimensional position information consisting of X, Y, and Z coordinates.

[0012] The axial base end of the rotating shaft 64 that forms the polishing module 40, i.e., the upper side of the rotating shaft 64, is connected to an electric drive motor 14 that rotates the rotating shaft 64. Meanwhile, the axial tip end of the rotating shaft 64, i.e., the lower side of the rotating shaft 64, is provided with a polishing pad 15 that polishes the surface of the workpiece 11. The control unit 13 can also control the drive motor 14, which causes the polishing pad 15 to rotate in a predetermined rotation direction at a predetermined rotation speed.

[0013] The vertical articulated robot 20 corresponds to the robot in the present invention, the polishing module 40 corresponds to the robot end effector in the present invention, the drive motor 14 corresponds to the drive source in the present invention, and the polishing pad 15 corresponds to the rotary tool and polishing tool in the present invention.

[0014] Furthermore, the control unit 13 can also control the first voice coil motor VCM1 and the second voice coil motor VCM2 (see FIG. 3) that form the polishing module 40. This causes the polishing pad 15 to move downward together with the rotation shaft 64, thereby precisely adjusting the pressing force F (see FIG. 1) of the polishing pad 15 against the workpiece 11.

[0015] More specifically, the control unit 13 drives the vertical articulated robot 20 to perform "position control" for positioning the polishing pad 15 at a specified position on the surface of the workpiece 11. The control unit 13 also performs "rotation control" for driving the drive motor 14 to control the rotation speed of the polishing pad 15. Furthermore, the control unit 13 controls the first and second voice coil motors VCM1 and VCM2 to perform "pressing force control" for controlling the pressing force F of the polishing pad 15 against the workpiece 11.

[0016] This allows the polishing apparatus 10 to polish the surface of the workpiece 11, which has complex irregularities, to a predetermined surface roughness. Examples of the workpiece 11 include convex and concave lenses used in astronomical telescopes, and molds used in injection molding of washbasins and bathtubs.

[0017] As shown in Figure 1, the extension direction of the line connecting the vertical articulated robot 20 and the workbench 12 (left-right direction in the figure) is defined as the "front-to-back direction," the standing direction of the vertical articulated robot 20 and the workbench 12 (up-down direction in the figure) is defined as the "up-down direction," and the direction perpendicular to both the "front-to-back direction" and the "up-down direction" (depth direction in the figure) is defined as the "left-to-right direction."

[0018] 1 shows the posture of the vertical articulated robot 20 when the vertical articulated robot 20 is in a standby state (neutral state). Below, a detailed description will be given by defining the front-rear direction, left-right direction, and up-down direction based on the neutral state shown in FIG.

[0019] <Vertical articulated robot> 1, the vertical articulated robot 20 includes a robot base 21 fixed to a floor surface FL. The robot base 21 is provided with a first arm unit 22 that is rotatable as shown by the dashed arrow R1 around a first axis C1 that extends in the vertical direction relative to the floor surface FL. The vertical articulated robot 20 also includes a second arm unit 23, a third arm unit 24, a fourth arm unit 25, and a fifth arm unit 26.

[0020] The base end of the second arm unit 23 is connected to the tip end of the first arm unit 22 so as to be rotatable around the second axis C2 as indicated by the dashed arrow R2. The base end of the third arm unit 24 is connected to the tip end of the second arm unit 23 so as to be rotatable around the third axis C3 as indicated by the dashed arrow R3. The base end of the fourth arm unit 25 is connected to the tip end of the third arm unit 24 so as to be rotatable around the fourth axis C4 as indicated by the dashed arrow R4. The base end of the fifth arm unit 26 is connected to the tip end of the fourth arm unit 25 so as to be rotatable around the fifth axis C5 as indicated by the dashed arrow R5.

[0021] The second axis C2 to the fifth axis C5 indicated by black dots in Figure 1 extend in the left-right direction of the vertical articulated robot 20 and serve as the rotation centers of servo motors (not shown) built into the joints of the vertical articulated robot 20.

[0022] Here, the fifth arm unit 26 is rotatable as indicated by the dashed arrow R6 about a sixth axis C6 extending in the front-rear direction of the vertical articulated robot 20. This allows the polishing module 40 attached to the tip of the fifth arm unit 26 to move three-dimensionally with the movement of the fifth arm unit 26. Here, a chuck mechanism 26a is provided at the tip of the fifth arm unit 26. The chuck mechanism 26a can firmly grip the support pin 52 (see FIG. 2) of the polishing module 40 without any rattle.

[0023] <Polishing module> 2 to 4, the polishing module 40 is formed in a roughly cubic shape having six sides. Specifically, the polishing module 40 includes a fixed unit 50 attached to the fifth arm section 26 (see FIG. 1) of the vertical articulated robot 20, a movable unit 60 movable relative to the fixed unit 50, and a cover 70 that forms the outer shell of the polishing module 40 and covers the fixed unit 50 and the movable unit 60.

[0024] The cover 70 covers five of the six surfaces that form the polishing module 40, excluding one surface of the fixed base 51 on which the support pins 52 of the fixed unit 50 are provided. The cover 70 is fixed to the fixed unit 50 with a plurality of fixing screws S. This prevents polishing debris, dust, and the like from entering the interior of the polishing module 40.

[0025] <Fixed unit> 3 to 8, the fixed unit 50 forming the polishing module 40 is a unit that is attached to the fifth arm section 26 (see FIG. 1) of the vertical articulated robot 20. The fixed unit 50 has a fixed base 51 that is fixed to the fifth arm section 26, and the fixed base 51 is formed into a substantially square shape from a steel plate or the like.

[0026] The fixing unit 50 corresponds to the fixing member in this invention.

[0027] A support pin 52 is attached to the rear and central portion of the fixed base 51. The support pin 52 is gripped by a chuck mechanism 26a (see FIG. 1) provided at the tip (front side) of the fifth arm portion 26, and can be firmly fixed to the chuck mechanism 26a without any rattle.

[0028] Furthermore, a fixed base support part 53 that movably supports the movable unit 60 is provided at the front center of the fixed base 51. Specifically, the fixed base support part 53 has a pair of fixed side rails 53a that extend in the vertical direction of the fixed base 51. This allows the movable unit 60 to move relative to the fixed unit 50 in the direction in which the fixed side rails 53a extend, i.e., in the axial direction of the rotation shaft 64.

[0029] Furthermore, a power supply connection part 54 is provided on the front side of the fixed base 51 and on the left side of the fixed base side support part 53, for supplying drive current to each of the first coil CL1 and the second coil CL2 (see FIG. 9) provided in the movable unit 60. Specifically, the power supply connection part 54 has a power supply side connector connection part 54a formed in a substantially box shape, and the power supply side connector connection part 54a opens on the upper side (drive motor 14 side) and allows a power supply connector (not shown) provided on the vertical articulated robot 20 side to be inserted therein.

[0030] The power supply connection section 54 is provided with a flexible flat cable 54b that is flexibly deformable and formed into a film. One side of the flexible flat cable 54b is electrically connected to the power supply connector connection section 54a, and the other side of the flexible flat cable 54b is electrically connected to the first and second coils CL1 and CL2, respectively. This allows the movable unit 60 (see FIG. 9) having the first and second coils CL1 and CL2 to move relative to the fixed unit 50 in response to the supply of drive current.

[0031] Furthermore, an encoder unit 55 is provided on the front side of the fixed base 51 and to the right of the fixed base support part 53 to detect the position of the movable unit 60 relative to the fixed unit 50, i.e., the movement state. Specifically, the encoder unit 55 is provided between the fixed base 51 and the movable base 61, and corresponds to the encoder in this invention.

[0032] The encoder unit 55 has a sensor-side connector connection portion 55a formed in a substantially box shape, which opens on the upper side (the drive motor 14 side) and into which a sensor connector (not shown) provided on the vertical articulated robot 20 side can be inserted. A detection signal from the encoder unit 55 is sent to the control unit 13. That is, the control unit 13 can grasp the position of the movable unit 60 relative to the fixed unit 50.

[0033] The encoder unit 55 is equipped with an optical sensor 55b that emits light toward the movable unit 60 and receives reflected light from the movable unit 60. Here, a linear scale 63 (see FIGS. 5 and 10) made up of a plurality of reflective portions (white) and a plurality of non-reflective portions (black) arranged in the moving direction of the movable unit 60 is provided at a location (facing portion) of the movable unit 60 facing the optical sensor 55b. This allows the control unit 13 (see FIG. 1) to grasp the position of the movable unit 60 relative to the fixed unit 50 by counting the number of times the reflected light is received.

[0034] Furthermore, a first fixed base sidewall 56 and a second fixed base sidewall 57, each formed into a substantially square shape from a steel plate or the like, are fixed to the left and right sides of the fixed base 51. Specifically, the first fixed base sidewall 56 has a first upright wall 56a that stands upright from the fixed base 51 to the front side (toward the workbench 12) on the left side of the fixed base 51. Furthermore, the second fixed base sidewall 57 has a second upright wall 57a that stands upright from the fixed base 51 to the front side (toward the workbench 12) on the right side of the fixed base 51. The plate thicknesses of the first and second upright walls 56a, 57a are slightly thinner than the plate thickness of the fixed base 51.

[0035] The first fixed base sidewall 56 is equipped with a first magnet holder 56b, which has a generally U-shaped cross section and is disposed on the second upright wall 57a side (right side) of the first upright wall 56a. The first magnet holder 56b abuts against the first upright wall 56a, forming a space between them. A total of six plate-shaped permanent magnets MG1, MG2, MG3, MG4, MG5, and MG6 are housed inside the first fixed base sidewall 56.

[0036] 6, three permanent magnets MG1, MG3, and MG5 are fixed to the first upright wall 56a in this order from top to bottom. The other three permanent magnets MG2, MG4, and MG6 are fixed to the first magnet holder 56b in this order from top to bottom. In this way, the permanent magnets MG1, MG3, and MG5 and the permanent magnets MG2, MG4, and MG6 are aligned in the vertical direction of the fixing unit 50, respectively.

[0037] Furthermore, the permanent magnets MG1 and MG2, the permanent magnets MG3 and MG4, and the permanent magnets MG5 and MG6 are arranged opposite each other with a gap in the left-right direction of the fixed unit 50, i.e., in a direction perpendicular to the axial direction of the rotation shaft 64, and a first gap G1 (see Figures 7 and 8) is formed between them.

[0038] Furthermore, the second fixed base sidewall 57 is provided with a second magnet holder 57b, which has a generally U-shaped cross section and is disposed on the first upright wall 56a side (left side) of the second upright wall 57a. The second magnet holder 57b abuts against the second upright wall 57a, forming a space between them. A total of six plate-shaped permanent magnets MG1, MG2, MG3, MG4, MG5, and MG6 are also housed inside the second fixed base sidewall 57.

[0039] 6, three permanent magnets MG1, MG3, and MG5 are fixed to the second magnet holder 57b in this order from top to bottom. The other three permanent magnets MG2, MG4, and MG6 are fixed to the second upright wall 57a in this order from top to bottom. In this way, the permanent magnets MG1, MG3, and MG5 and the permanent magnets MG2, MG4, and MG6 on the second fixed base sidewall portion 57 side are also lined up in the vertical direction of the fixed unit 50.

[0040] In addition, the permanent magnets MG1 and MG2, the permanent magnets MG3 and MG4, and the permanent magnets MG5 and MG6 on the second fixed base side wall portion 57 side are also arranged opposite each other with a gap in the left-right direction of the fixed unit 50, and a second gap G2 (see Figures 7 and 8) is formed between them.

[0041] The first movable base side wall portion 67 of the movable unit 60 is accommodated in the first gap G1 via a minute gap (air gap) so as to be movable in the axial direction of the rotation shaft 64. The second movable base side wall portion 68 of the movable unit 60 is accommodated in the second gap G2 via a minute gap (air gap) so as to be movable in the axial direction of the rotation shaft 64.

[0042] Here, the first fixed base side wall portion 56 and the second fixed base side wall portion 57 are arranged opposite to each other across the axis AC of the rotation shaft 64. The first fixed base side wall portion 56 and the second fixed base side wall portion 57 correspond to a pair of fixed walls in the present invention.

[0043] Furthermore, six permanent magnets MG1, MG2, MG3, MG4, MG5, and MG6 are provided on each of the left and right sides of fixed unit 50, and form the stators of first voice coil motor VCM1 and second voice coil motor VCM2 (see FIG. 3), respectively. In other words, permanent magnets MG1, MG2, MG3, MG4, MG5, and MG6 each correspond to the stator in the present invention.

[0044] Furthermore, a guide member 58 is fixed to the underside (polishing pad 15 side) of the fixed base 51. The guide member 58 slidably supports a rotation shaft bracket 66 that rotatably supports a rotation shaft 64. This allows the fixed unit 50 to stably support the rotation shaft bracket 66 fixed to the movable unit 60 without shaking.

[0045] Here, a guide cover 58a is attached to the guide member 58. The guide cover 58a covers the sliding portion between the guide member 58 and the rotary shaft bracket 66, thereby preventing abrasive chips, dust, and the like from entering between the guide member 58 and the rotary shaft bracket 66.

[0046] <Movable unit> 3 to 6, 9, and 10, the movable unit 60 forming the polishing module 40 is a unit that is movable together with a rotation shaft 64 relative to the fixed unit 50 in the axial direction of the rotation shaft 64. The movable unit 60 has a movable base 61 that faces the fixed base 51 of the fixed unit 50 in the front-to-rear direction of the polishing module 40. Like the fixed base 51, the movable base 61 is also formed into a substantially square shape from a steel plate or the like.

[0047] The movable unit 60 corresponds to the movable member in the present invention.

[0048] A pair of movable rails 62 are fixed to the rear side of the movable base 61, i.e., on the fixed base 51 side, and these movable rails 62 extend in the vertical direction of the movable base 61. The pair of movable rails 62 are respectively engaged with a pair of fixed rails 53a (see FIG. 7) provided on the front side of the fixed base 51, i.e., on the movable base 61 side, and are movable in the axial direction of a rotation shaft 64 relative to the pair of fixed rails 53a.

[0049] In this way, fixed-side rail 53a and movable-side rail 62 are provided between fixed base 51 and movable base 61 to guide movement of movable base 61 relative to fixed base 51. Note that fixed-side rail 53a and movable-side rail 62 correspond to the rail members in the present invention.

[0050] Here, the fixed rail 53a and the movable rail 62 are free from rattle in the front-rear and left-right directions and are capable of smooth relative movement only in the up-down direction. Therefore, a large driving force is not required to move the movable unit 60, and the first and second voice coil motors VCM1 and VCM2 do not need to be large. Note that the fixed rail 53a and the movable rail 62 may be, for example, linear guides that allow smooth relative movement (linear movement) without oil supply.

[0051] Further, a linear scale 63 is provided on the rear and right side of the movable base 61, facing the optical sensor 55b (see FIG. 8) of the encoder unit 55 provided on the fixed base 51. Specifically, the linear scale 63 faces the optical sensor 55b in the front-rear direction of the polishing module 40, and is disposed further to the left of the movable-side rail 62 disposed on the left side of the movable base 61.

[0052] The linear scale 63 extends in the front-to-rear direction of the movable base 61, and moves in a non-contact manner over the optical sensor 55b during relative movement between the movable unit 60 and the fixed unit 50. This allows the control unit 13 to grasp the movement state of the movable unit 60 relative to the fixed unit 50.

[0053] Furthermore, the movable unit 60 includes a rotary shaft 64 that rotates the polishing pad 15 (see FIG. 1). The rotary shaft 64 is rotated by the drive motor 14 (see FIG. 1) and rotates the polishing pad 15 (see FIG. 1). As shown in FIG. 6, the rotary shaft 64 is formed from a stepped, solid round steel bar and rotates about an axis AC. Specifically, the rotary shaft 64 has a large-diameter portion 64a, a medium-diameter portion 64b, and a small-diameter portion 64c. The upper axial side of the medium-diameter portion 64b is coupled to the drive motor 14 so as to transmit power, and the polishing pad 15 is provided on the lower axial side of the small-diameter portion 64c so as to be integrally rotatable. Both the drive motor 14 and the polishing pad 15 are disposed on the axis AC, which allows the rotary shaft 64 to rotate at high speed without wobbling.

[0054] Additionally, radial bearings 65 that rotatably support the rotating shaft 64 are provided on the steps on both axial sides of the large diameter portion 64a. As a result, the rotating shaft 64 is rotatably supported by the rotating shaft bracket 66 via the pair of radial bearings 65. The pair of radial bearings 65 are attached to the steps on both axial sides of the large diameter portion 64a. Therefore, the axial movement of the rotating shaft 64 is restricted with respect to the pair of radial bearings 65.

[0055] A rotating shaft bracket 66, which rotatably supports the rotating shaft 64, is fixed to the front side of the movable base 61. That is, the rotating shaft 64, which includes the drive motor 14 and the polishing pad 15, is movable up and down together with the movable base 61 relative to the fixed base 51. The rotating shaft bracket 66 is formed in a stepped, hollow cylindrical shape, and a pair of annular grooves 66a is formed on the radially inner side of the rotating shaft bracket 66. Radial bearings 65 are mounted in these annular grooves 66a, respectively. That is, the rotating shaft bracket 66 has the function of restricting axial movement of the rotating shaft 64 relative to the movable base 61.

[0056] Furthermore, a first movable base side wall portion 67 and a second movable base side wall portion 68 are fixed to the left and right sides of the movable base 61, and these first and second movable base side wall portions 67, 68 are arranged opposite each other across the axis AC of the rotation shaft 64.

[0057] Here, the first movable base sidewall portion 67 includes a first frame body 67a and a first coil CL1 and a second coil CL2 fixed to the inside of the first frame body 67a. Specifically, the first frame body 67a is a roughly square steel frame with a hollowed-out interior, and the first and second coils CL1 and CL2 are formed by winding copper wire with excellent conductivity into an oval shape. The first and second coils CL1 and CL2 are connected in series to each other inside the first frame body 67a.

[0058] The first movable base sidewall 67, which is composed of the first frame 67a and the first and second coils CL1 and CL2, fits into a first gap G1 (see FIG. 5) formed inside the first fixed base sidewall 56 when the polishing module 40 is assembled. That is, the first movable base sidewall 67 faces the first fixed base sidewall 56. The first and second coils CL1 and CL2 are also disposed between the permanent magnets MG1, MG3, MG5 and the permanent magnets MG2, MG4, MG6.

[0059] Here, the permanent magnets MG1 to MG6 that form the first gap G1 and the first and second coils CL1 and CL2 of the first frame 67a form a first voice coil motor VCM1.

[0060] The first voice coil motor VCM1 is an actuator that generates a driving force to move the movable unit 60 up and down relative to the fixed unit 50 by supplying a driving current to the first and second coils CL1, CL2. In other words, the first and second coils CL1, CL2 are moved in the axial direction of the rotation shaft 64 by the supply of a driving current. The first and second coils CL1, CL2 of the first voice coil motor VCM1 are supplied with a driving current from the control unit 13 via the flexible flat cable 54b.

[0061] Here, the first movable base side wall portion 67 corresponds to one of the movable wall portions in the present invention, the first and second coils CL1 and CL2 fixed to the first frame body 67a correspond to the mover in the present invention, and the first voice coil motor VCM1 corresponds to one of the electric motors in the present invention.

[0062] In contrast, the second movable base sidewall 68 includes a second frame 68a and a first coil CL1 and a second coil CL2 fixed to the inside of the second frame 68a. Like the first frame 67a, the second frame 68a is also a substantially square steel frame. The first and second coils CL1 and CL2 fixed to the second frame 68a are the same as the first and second coils CL1 and CL2 fixed to the first frame 67a.

[0063] The second movable base sidewall 68, which is composed of the second frame 68a and the first and second coils CL1 and CL2, fits into a second gap G2 (see FIG. 5) formed inside the second fixed base sidewall 57 when the polishing module 40 is assembled. That is, the second movable base sidewall 68 faces the second fixed base sidewall 57. The first and second coils CL1 and CL2 are disposed between the permanent magnets MG1, MG3, MG5 and the permanent magnets MG2, MG4, MG6.

[0064] Here, the permanent magnets MG1 to MG6 that form the second gap G2 and the first and second coils CL1 and CL2 of the second frame 68a form a second voice coil motor VCM2.

[0065] Here, like the first voice coil motor VCM1, the second voice coil motor VCM2 is an actuator that generates a driving force that moves the movable unit 60 up and down relative to the fixed unit 50 when a driving current is supplied to the first and second coils CL1 and CL2. In other words, when a driving current is supplied, the first and second coils CL1 and CL2 are moved in the axial direction of the rotation shaft 64. Note that a driving current is also supplied to the first and second coils CL1 and CL2 of the second voice coil motor VCM2 from the control unit 13 via the flexible flat cable 54b.

[0066] The first and second coils CL1, CL2 of the first voice coil motor VCM1 and the first and second coils CL1, CL2 of the second voice coil motor VCM2 are connected in parallel to the flexible flat cable 54b, which allows the first and second voice coil motors VCM1, VCM2 to be driven in synchronization by the control unit 13 and to generate driving forces of the same magnitude with high precision.

[0067] The second movable base side wall portion 68 corresponds to the other movable wall portion in the present invention, the first and second coils CL1 and CL2 fixed to the second frame body 68a correspond to the mover in the present invention, and the second voice coil motor VCM2 corresponds to the other electric motor in the present invention.

[0068] 5, the first and second voice coil motors VCM1 and VCM2, which are driven in synchronization with each other and generate the same magnitude of driving force, are arranged opposite each other with the rotation shaft 64 (axis AC) in between. Specifically, the first and second voice coil motors VCM1 and VCM2 are arranged at equal distances from the rotation shaft 64. As a result, the first and second voice coil motors VCM1 and VCM2 generate the same magnitude of driving force when supplied with the same magnitude of driving current, and operate to cancel each other's moments.

[0069] Therefore, the control unit 13 can drive the first and second voice coil motors VCM1 and VCM2 with simple control logic, and the first and second voice coil motors VCM1 and VCM2 are driven in a balanced manner on the left and right sides of the polishing module 40, centered around the vicinity of the axis AC of the rotating shaft 64.

[0070] Therefore, the movable unit 60 can be moved relative to the fixed unit 50 without gouging along the axis AC of the rotating shaft 64. Furthermore, the polishing pad 15 rotated by the rotating shaft 64 can be pressed against the workpiece 11 (see FIG. 1) with a predetermined pressing force F. This prevents the polishing pad 15 from vibrating while rotating, making it possible to efficiently finish the surface of the workpiece 11 to a smooth finish.

[0071] Furthermore, a reinforcing frame 69 is fixed to the front sides of the first movable base side wall 67 and the second movable base side wall 68, i.e., the front sides of the first frame body 67a and the second frame body 68a. The reinforcing frame 69 is also a substantially square frame made of steel. The reinforcing frame 69 functions to prevent the first frame body 67a and the second frame body 68a, whose front sides are free ends, from swinging relative to the movable base 61.

[0072] This allows the first and second coils CL1 and CL2 (movers) of the first and second voice coil motors VCM1 and VCM2 to move smoothly and at high speed inside the first and second gaps G1 and G2 without coming into contact with the permanent magnets MG1 to MG6 (stators) of the first and second voice coil motors VCM1 and VCM2. In other words, the pressing force F (see FIG. 1) of the polishing pad 15 against the workpiece 11 can be adjusted at high speed (improved responsiveness).

[0073] <Operation description> Next, the operation of the polishing apparatus 10 configured as above, particularly the operation of the polishing module 40, will be described in detail with reference to FIGS.

[0074] 11, in the left-right direction of the first and second voice coil motors VCM1 and VCM2, the "south pole" of permanent magnet MG1 and the "north pole" of permanent magnet MG2 face each other via first and second gaps G1 and G2. Also, the "north pole" of permanent magnet MG3 and the "south pole" of permanent magnet MG4 face each other via first and second gaps G1 and G2. Furthermore, the "south pole" of permanent magnet MG5 and the "north pole" of permanent magnet MG6 face each other via first and second gaps G1 and G2.

[0075] As a result, the direction of magnetic flux B generated by each of the permanent magnets MG1 to MG6 is as shown by the arrows in the figure. That is, it flows from right to left at the location of permanent magnets MG1 and MG2, from left to right at the location of permanent magnets MG3 and MG4, and from right to left at the location of permanent magnets MG5 and MG6. When a drive current is passed through each of the first and second coils CL1 and CL2 as indicated by the symbols indicating the direction of current flow, according to Fleming's left-hand rule, the first and second coils CL1 and CL2 (movers) are moved below the first and second voice coil motors VCM1 and VCM2 within the first and second gaps G1 and G2.

[0076] At this time, the first and second coils CL1, CL2 are moved from the inside to the outside of the permanent magnets MG1 to MG6 (stators) so as to apply a pressing force F, and the pressing force F at this time is proportional to the magnitude of the drive current flowing through the first and second coils CL1, CL2. Note that by reversing the direction of the drive current flowing through the first and second coils CL1, CL2, the first and second coils CL1, CL2 move above the first and second voice coil motors VCM1, VCM2.

[0077] As a result, as shown by the dashed arrow RT in Figures 1 and 12, by rotating the rotating shaft 64 (polishing pad 15) around the axis AC and adjusting the magnitude of the drive current flowing through the first and second coils CL1 and CL2, the movable unit 60 can be moved relative to the fixed unit 50 as shown by the dashed arrow SL.

[0078] Therefore, the polishing pad 15 is pressed against the workpiece 11 with a predetermined pressing force F, and the surface of the workpiece 11 is finished to a predetermined surface roughness. As shown by the dashed arrow M in Fig. 1, by controlling the vertical articulated robot 20 during polishing and tilting the rotation axis 64, the outer periphery of the polishing pad 15 can be brought into contact with the workpiece 11. Therefore, it is possible to finish a region of the surface of the workpiece 11 with a small surface area to a predetermined surface roughness.

[0079] 12, the first and second movable base sidewalls 67, 68 of the movable unit 60 (shaded in the figure) are movable upward by a movement distance L1 and downward by a movement distance L2 inside the first and second magnet holders 56b, 57b of the fixed unit 50. Note that the symbol L3 in Fig. 12 denotes the length dimension along the vertical direction of the first and second gaps G1, G2, and the symbol W in Fig. 12 denotes the length dimension along the vertical direction of the first and second movable base sidewalls 67, 68.

[0080] That is, the formula (L3-W=L1+L2) is satisfied, and the first and second movable base side walls 67, 68 are moved by movement distances L1, L2 in the vertical direction (axial direction of the rotation shaft 64) relative to the first and second magnet holders 56b, 57b from the neutral state shown in Fig. 12, and thus the pressing force F can be adjusted to any magnitude. However, the total value of the movement distances L1, L2 is "10 mm to 20 mm" in this embodiment.

[0081] Furthermore, while the polishing module 40 is being controlled by the control unit 13 (during control), the first and second movable base side wall portions 67, 68 do not abut (collide) against the first and second magnet holders 56b, 57b in the vertical direction of the polishing module 40.

[0082] As described above in detail, this embodiment comprises a fixed unit 50 fixed to the vertical articulated robot 20, a movable unit 60 movable in the axial direction of the rotation shaft 64 together with the rotation shaft 64 relative to the fixed unit 50, and first and second voice coil motors VCM1, VCM2 having permanent magnets MG1 to MG6 and first and second coils CL1, CL2 and moving the movable unit 60 relative to the fixed unit 50, wherein the fixed unit 50 is provided with first and second fixed base sidewall portions 56, 57 arranged opposite each other across the rotation shaft 64 and to which the permanent magnets MG1 to MG6 are fixed, respectively, and the movable unit 60 is provided with first and second movable base sidewall portions 67, 68 arranged opposite each other across the rotation shaft 64, facing the first and second fixed base sidewall portions 56, 57, respectively, and to which the first and second coils CL1, CL2 are fixed, respectively.

[0083] This allows the first and second voice coil motors VCM1 and VCM2, which are driven in synchronization with each other and generate the same magnitude of driving force, to be arranged opposite each other with the rotation shaft 64 (axis AC) in between. Therefore, the first and second voice coil motors VCM1 and VCM2 can be driven in a balanced manner on the left and right sides of the polishing module 40, centered around the vicinity of the axis AC of the rotation shaft 64. This makes it possible to realize a polishing module 40 that can improve responsiveness while suppressing variations in processing accuracy.

[0084] Furthermore, according to this embodiment, the permanent magnets MG1 to MG6 are arranged facing each other at a distance in a direction perpendicular to the axial direction of the rotating shaft 64, and the movable unit 60 can be driven by the first and second voice coil motors VCM1 and VCM2, which are formed by arranging the first and second coils CL1 and CL2 in the first and second gaps G1 and G2.

[0085] This prevents the polishing module 40 from becoming too large, such as wide in the left-right direction, and ultimately makes it possible to realize a compact polishing module 40.

[0086] Furthermore, according to this embodiment, the fixed unit 50 has a fixed base 51 fixed to the vertical articulated robot 20, and the movable unit 60 has a movable base 61 facing the fixed base 51, and between the fixed base 51 and the movable base 61, a fixed side rail 53a and a movable side rail 62 are provided to guide the movement of the movable base 61 relative to the fixed base 51.

[0087] This allows the movable unit 60 to move smoothly only in the up and down direction without rattling in the front-to-back and left-to-right directions relative to the fixed unit 50. Therefore, a large driving force is not required to move the movable unit 60, and small first and second voice coil motors VCM1 and VCM2 can be used.

[0088] Furthermore, according to this embodiment, an encoder unit 55 is provided between fixed base 51 and movable base 61 to detect the state of movement of movable base 61 relative to fixed base 51 .

[0089] This allows the control unit 13 to accurately adjust the pressing force F of the polishing pad 15 against the workpiece 11. This makes it possible to efficiently finish the surface of the workpiece 11 to a smooth surface. Specifically, the control unit 13 calculates the target pressing force F based on the detection signal from the encoder unit 55, i.e., the position signal of the movable unit 60 relative to the fixed unit 50, and the magnitude of the drive current to the first and second voice coil motors VCM1 and VCM2.

[0090] Furthermore, according to this embodiment, movable base 61 is provided with rotational shaft bracket 66 that rotatably supports rotational shaft 64 and restricts axial movement of rotational shaft 64 relative to movable base 61.

[0091] This allows the movable base 61 to move up and down relative to the fixed base 51 while the rotation shaft 64 is rotated.

[0092] Furthermore, according to this embodiment, the axial base end (upper side) of the rotating shaft 64 is connected to a drive motor 14 that rotates the rotating shaft 64, and a polishing pad 15 is provided at the axial tip end (lower side) of the rotating shaft 64.

[0093] This allows the drive motor 14 and the polishing pad 15 rotated by the drive motor 14 to be arranged on the axis AC of the rotating shaft 64, thereby effectively suppressing rotational wobble of the rotating shaft 64. This allows the polishing pad 15 to rotate at high speed, thereby shortening the processing time and saving manufacturing energy.

[0094] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, the polishing module 40 is shown in which the first and second voice coil motors VCM1, VCM2 are disposed at equal distances from the rotation axis 64, but the present invention is not limited to this. For example, the present invention can also be applied to cases in which the layout of the polishing module 40 relative to the vertical articulated robot 20 requires that the first and second voice coil motors VCM1, VCM2 be disposed at different distances from the rotation axis 64.

[0095] In this case, for example, if the distance between the first voice coil motor VCM1 (generating a pressing force F1) and the rotating shaft 64 is L1 and the distance between the second voice coil motor VCM2 (generating a pressing force F2) and the rotating shaft 64 is L2, the pressing force F on the workpiece 11 is the resultant force of the pressing forces F1 and F2, so "F = F1 + F2".

[0096] Then, in order to cancel out the moments, the control unit 13 can be made to calculate the pressing forces F1 and F2 of the first and second voice coil motors VCM1 and VCM2 so as to satisfy "F1×L1=F2×L2 (F2 / F1=L1 / L2)." In other words, the control unit 13 can be made to individually control the pressing forces F1 and F2 of the first and second voice coil motors VCM1 and VCM2.

[0097] In the above embodiment, the first and second voice coil motors VCM1 and VCM2 each include a total of six permanent magnets (three sets) MG1 to MG6, but the present invention is not limited to this, and the number of permanent magnets can be set as desired depending on the specifications of the polishing module 40, i.e., the required driving force, relative movement distance, etc. Furthermore, the number of coils can also be set as desired corresponding to the number of permanent magnets.

[0098] Furthermore, in the above embodiment, the rotary tool is shown as a polishing pad (polishing tool) 15, but the present invention is not limited to this, and the rotary tool may be, for example, a drill, which drills a hole while pressing the rotary tool against the workpiece 11.

[0099] Furthermore, in the above embodiment, the electric drive motor 14 is shown as the drive source for rotating the rotary shaft 64, but the present invention is not limited to this, and an air motor or the like that is driven to rotate using compressed air pressure as a power source can also be used.

[0100] In addition, in the above embodiment, an encoder unit 55 having an optical sensor 55b is used as the encoder, but the present invention is not limited to this, and a magnetic encoder having a magnetic sensor (such as a Hall element or an MR sensor) can also be used.

[0101] Furthermore, the material, shape, size, number, installation location, etc. of each component in the above-described embodiments are arbitrary as long as they can achieve the present invention, and are not limited to the above-described embodiments. [Explanation of symbols]

[0102] 10... Polishing device, 11... Workpiece, 12... Work table, 13... Control unit, 14... Drive motor (drive source), 15... Polishing pad (rotary tool, polishing tool), 20... Vertical articulated robot (robot), 21... Robot base, 22... First arm section, 23... Second arm section, 24... Third arm section, 25... Fourth arm section, 26... Fifth arm section, 26a... Chuck mechanism, 40... Polishing module (robot end effector), 50... Fixing unit (fixing member), 51 ...Fixed base, 52...Support pin, 53...Fixed base side support portion, 53a...Fixed side rail (rail member), 54...Power supply connection portion, 54a...Power supply side connector connection portion, 54b...Flexible flat cable, 55...Encoder unit (encoder), 55a...Sensor side connector connection portion, 55b...Optical sensor, 56...First fixed base side wall portion (fixed wall portion), 56a...First upright wall, 56b...First magnet holder, 57...Second fixed base side wall portion (fixed wall portion), 57a...Second Standing wall, 57b...second magnet holder, 58...guide member, 58a...guide cover, 60...movable unit (movable member), 61...movable base, 62...movable side rail (rail member), 63...linear scale, 64...rotating shaft, 64a...large diameter portion, 64b...medium diameter portion, 64c...small diameter portion, 65...radial bearing, 66...rotating shaft bracket, 66a...annular groove, 67...first movable base side wall portion (movable wall portion), 67a...first frame body, 68...second movable base side wall portion (movable wall portion), 68 a...second frame, 69...reinforcing frame, 70...cover, AC...axis, B...magnetic flux, C1...first axis, C2...second axis, C3...third axis, C4...fourth axis, C5...fifth axis, C6...sixth axis, CL1...first coil (mover), CL2...second coil (mover), F...pressing force, FL...floor, G1...first gap, G2...second gap, MG1 to MG6...permanent magnet (stator), S...fixing screw, VCM1...first voice coil motor (electric motor), VCM2...second voice coil motor (electric motor)

Claims

1. An end effector for a robot having a rotary shaft for rotating a rotary tool, a fixed member fixed to the robot; a movable member movable together with the rotary shaft in an axial direction of the rotary shaft relative to the fixed member; a pair of electric motors each having a stator and a mover, the electric motors moving the moveable member relative to the fixed member; Equipped with The fixed member is provided with a pair of fixed wall portions that are arranged opposite to each other with the rotation shaft therebetween and to which the stators are respectively fixed, The movable member is provided with a pair of movable wall portions that are arranged opposite to each other across the rotation axis, that face the pair of fixed wall portions, and that have the movers fixed thereto. Robot end effector.

2. The robot end effector according to claim 1, the stator includes at least one pair of permanent magnets arranged opposite to each other with a gap therebetween in a direction perpendicular to the axial direction of the rotation shaft, the mover is disposed between the pair of permanent magnets and includes at least one coil that is moved in the axial direction of the rotation shaft by supplying a drive current thereto. Robot end effector.

3. The robot end effector according to claim 1, the fixed member includes a fixed base fixed to the robot; the movable member includes a movable base facing the fixed base, a rail member is provided between the fixed base and the movable base to guide movement of the movable base relative to the fixed base; Robot end effector.

4. The robot end effector according to claim 3, an encoder is provided between the fixed base and the movable base to detect a movement state of the movable base relative to the fixed base; Robot end effector.

5. The robot end effector according to claim 3, The movable base is provided with a rotation shaft bracket that rotatably supports the rotation shaft and restricts axial movement of the rotation shaft relative to the movable base. Robot end effector.

6. The robot end effector according to claim 1, a base end portion of the rotary shaft in the axial direction is connected to a drive source that rotates the rotary shaft; The rotary tool is provided at a tip end of the rotary shaft in an axial direction. Robot end effector.

7. The robot end effector according to claim 6, The rotary tool is a polishing tool for polishing the surface of the workpiece. Robot end effector.

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