Robot tool

Abstract

To provide a robot tool capable of aligning a screw or a gauge with a screw hole even if slight displacement of a position and an angle of a seat surface occurs.SOLUTION: A robot tool includes a shaft member (15, 27) having at least one end provided with a gauge (15A) for inspecting a screw hole diameter or a bit (27A) for tightening and loosening a screw, a motor (12) accommodating the shaft member (15, 27) in a cylindrical motor shaft (12A) so as to be movable up and down, a cylindrical guide (17) disposed so that the shaft member (15, 27) can be inserted therethrough and having a tip in contact with a seat surface (W1), and a force sensor (16) configured to detect a moment received by the guide (17) from the seat surface (W1) when a part of the tip of the guide (17) is in contact with the seat surface (W1).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a robot tool that is attached to the tip of a robot arm. [Background technology]

[0002] Patent Document 1 describes the configuration of a screw tightening robot in which a driver tool is attached to the tip of an articulated arm via a force sensor. The driver tool also has a cushion spring that constantly urges the bit toward the workpiece. The force sensor is mounted on the driver tool and detects the load, including the driver tool's own weight, and transmits the detected load to control means as appropriate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-188503 Summary of the Invention [Problem to be solved by the invention]

[0004] Such screw-driving robots require precise teaching to accurately align the screw hole and screw. Even with teaching, even a slight deviation in the position or angle of the seating surface can cause the screw to shift or tilt relative to the screw hole, making it impossible to tighten the screw. This type of problem can occur not only with screw-driving robots, but also with inspection robots that tighten a threaded bit into a screw hole to check whether the screw hole meets specified conditions.

[0005] One aspect of the present invention has been made in consideration of the above-mentioned problems, and aims to provide a robot tool that can align a screw or gauge with a screw hole even if there is a slight misalignment in the position and angle of the seating surface. [Means for solving the problem]

[0006] In order to solve the above problems, a robot tool according to one aspect of the present invention includes a shaft member having at least one end provided with a gauge for inspecting screw hole diameters or a bit for tightening or loosening screws, a motor that accommodates the shaft member so that it can be raised and lowered within a cylindrical motor shaft, a cylindrical guide that is positioned so that the shaft member can be inserted and whose tip contacts a seating surface, and a force sensor that detects the moment that the guide receives from the seating surface when a portion of the tip of the guide contacts the seating surface. [Effects of the Invention]

[0007] According to one aspect of the present invention, even if the angle of the seating surface is slightly misaligned, the force sensor can be used to virtually eliminate the moment the guide tip receives from the seating surface, thereby setting the shaft member at a predetermined angle relative to the seating surface. For example, it can be made perpendicular. As a result, by sliding the tip of the guide on the seating surface via the tip of the robot arm, the shaft member can be used to search for a screw hole. Then, by using the force sensor to detect that the tip of the screw or gauge has reached the screw hole, the screw or gauge and the screw hole can be aligned. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a robot using a robot tool of the present invention. [Figure 2] FIG. 2 is a perspective view of the robot tool shown in FIG. 1 as seen from above. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] 4 is an exploded perspective view of the stopper, compression coil spring, gauge shaft, and support plate of FIG. 3. FIG. [Figure 5] 4 is an enlarged perspective view of the guide of FIG. 3 as viewed from below, showing a state in which a lower stopper and a compression coil spring have been removed. FIG. [Figure 6] FIG. 2 is a perspective view showing an example of a screw-tightening shaft. [Figure 7]1. FIG. 4 is a diagram illustrating a first step of a fitting operation in which a gauge shaft is fitted into a screw hole using the robot tool shown in FIG. [Figure 8] 1. FIG. 4 is a view illustrating a second step of the fitting operation of fitting the gauge shaft into the screw hole using the robot tool shown in FIG. [Figure 9] 1. FIG. 4 is a view illustrating a third step of the fitting operation of fitting the gauge shaft into the screw hole using the robot tool shown in FIG. [Figure 10] 1. FIG. 4 is a view illustrating a fourth step of the fitting operation of fitting the gauge shaft into the screw hole using the robot tool shown in FIG. [Figure 11] 1. FIG. 4 is a view illustrating a fifth step of the fitting operation of fitting the gauge shaft into the screw hole using the robot tool shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to FIGS.

[0010] [General Configuration of Robot 100] A schematic configuration of a robot 100 using a robot tool 11 according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a diagram showing an example of the schematic configuration of a robot 100 using a robot tool 11 according to the present invention. FIG. 1 shows the X-axis, Y-axis, and Z-axis directions, which are orthogonal to each other. Therefore, the X-axis and Y-axis directions are two orthogonal directions that form a plane with the Z-axis direction as its normal. The Z-axis direction is a direction parallel to the motor shaft 12A shown in FIG. 3 of the motor 12 that constitutes the robot tool 11, and the direction upward with respect to the base plate 13 is defined as the positive Z-axis direction. Note that when referring to directions, reference is made to the directional arrows shown in the figure (the same applies to other figures).

[0011] 1, the robot 100 is configured so that a cylindrical gauge 15A for inspecting the diameter of a screw hole can be fitted into a screw hole W2 formed in a seating surface W1 of a workpiece W, as will be described later. The robot 100 includes a robot arm 101, a robot tool 11 attached to the tip of the robot arm 101, and a controller 102. The robot arm 101 is an articulated arm formed by connecting multiple arms.

[0012] The controller 102 has a CPU (Central Processing Unit) 111, a ROM (Read Only Memory) 112, and a RAM (Random Access Memory) 113, which are connected by a bus. The motor 12 and the force sensor 16 that constitute the robot tool 11, and the robot arm 101 are electrically connected to the controller 102.

[0013] The ROM 112 stores programs and the like for the CPU 111 to control various operations. The controller 102 controls the motor 12, the robot arm 101, and the like in response to detection signals input from the force sensor 16, as will be described later, based on the control programs read from the ROM 112. The RAM 113 is used as a storage area for temporarily storing data, signals, and the like used when the CPU 111 executes the programs, or as a working area for data processing.

[0014] [Outline of Robot Tool 11] Next, the schematic configuration of the robot tool 11 attached to the tip of the robot arm 101 will be described with reference to Figs. 2 to 5. Fig. 2 is a perspective view of the robot tool 11 shown in Fig. 1 as seen from above. Fig. 3 is a cross-sectional view taken along the line III-III in Fig. 2. Fig. 4 is an exploded perspective view of the stopper 23, compression coil spring 25, gauge shaft 15, and support plate 21 shown in Fig. 3. Fig. 5 is an enlarged perspective view of the guide 17 shown in Fig. 3 as seen from below, showing a state in which the lower stopper 23 and compression coil spring 25 shown in Fig. 3 have been removed.

[0015] 2 and 3, the robot tool 11 is composed of a motor 12, a base plate 13, a gauge shaft 15, a force sensor 16, a guide 17, etc. As shown in Fig. 2, the base plate 13 is formed in a rectangular shape in a plan view, with a short side that is approximately the same as one side of the mounting plate 16A, which is approximately square in a plan view, of the force sensor 16. The longitudinal direction of the base plate 13 is defined as the X-axis direction, and the short side direction is defined as the Y-axis direction.

[0016] The force sensor 16 is fixed by screws to one longitudinal end of the upper surface of the base plate 13, i.e., the surface opposite the seat surface W1, via a mounting plate 16A attached to the lower end surface of the force sensor 16. The upper end of the force sensor 16 is attached to the tip of the robot arm 101.

[0017] The force sensor 16 is a six-axis force sensor that detects force components FX, FY, and FZ acting on the robot tool 11 in the directions of three axes, i.e., the X-axis, Y-axis, and Z-axis, and moment components MX, MY, and MZ about the X-axis, Y-axis, and Z-axis as rotation axes. The force sensor 16 outputs detection signals of the detected force components FX, FY, and FZ and moment components MX, MY, and MZ to the electrically connected controller 102 via a connector 16B. When it is not necessary to distinguish between the directions, the force components FX, FY, and FZ are also collectively referred to as force F, and the moment components MX, MY, and MZ are also collectively referred to as moment M.

[0018] 2 and 3, a circular through-hole 13A is formed in the approximate center of approximately half of the upper surface of the base plate 13 on the longitudinally opposite side of the force sensor 16, through which the cylindrical motor shaft 12A of the motor 12 protrudes downward, i.e., toward the seat surface W1. The motor 12 is fixed by screws via a mounting plate 12B attached to the lower end of the motor 12 so that the motor shaft 12A is positioned approximately in the center of the through-hole 13A. The through-hole 13A is an example of a first through-hole.

[0019] Furthermore, on the underside of the base plate 13, that is, on the surface on the side of the seating surface W1, a cylindrical guide 17 whose tip (lower end in FIG. 3) comes into contact with the seating surface W1 of the workpiece W is fixed by screws so as to be coaxial with the through-hole 13A. Note that the cross section of the guide 17 is not limited to being circular, and it may be formed in a cylindrical shape with a polygonal cross section such as a square or hexagon.

[0020] As shown in Fig. 3, motor shaft 12A is cylindrical and has an annular flange 12C extending radially outward from its tip (the lower end in Fig. 3) by a predetermined length, for example, about 5 to 7 mm. Six screw holes 12D, for example, are formed in flange 12C at equal intervals around the circumference. A disk-shaped support plate 21, which transmits the rotation of motor shaft 12A to gauge shaft 15, is fixed to flange 12C by screws into screw holes 12D.

[0021] As shown in Figures 3 and 4, the gauge shaft 15 housed in the cylindrical motor shaft 12A is formed from a shaft portion 15B with a hexagonal cross section and a pair of cylindrical gauges 15A formed coaxially on both ends of the shaft portion 15B. The diameter of the gauge 15A is set to be smaller than the diameter of the inscribed circle of the cross section of the shaft portion 15B. The pair of gauges 15A are inserted into a screw hole W2 formed in a workpiece W to determine the size of the hole diameter. The gauge shaft 15 is an example of a shaft member.

[0022] As shown in FIG. 4, a hexagonal through-hole 21A is formed in the center of the support plate 21, into which the shaft portion 15B of the gauge shaft 15 is inserted. At each corner of the through-hole 21A, a U-shaped cross-section relief groove 21B is formed across the entire thickness. As shown in FIGS. 4 and 5, by fitting the shaft portion 15B of the gauge shaft 15 into the through-hole 21A of the support plate 21, the gauge shaft 15 can be raised and lowered within the motor shaft 12A and is accommodated coaxially. Furthermore, because each corner of the hexagonal cross-section of the shaft portion 15B is positioned within each relief groove 21B, it is possible to prevent the corner of the shaft portion 15B from hitting the inner circumferential surface of the through-hole 21A and becoming unable to be inserted. The through-hole 21A is an example of a second through-hole.

[0023] The cross-sectional shape of shaft portion 15B and the shape of through hole 21A are not limited to a hexagon, but may be a rectangle, a pentagon, an octagon, etc. Furthermore, relief grooves 21B having a U-shaped cross section may be formed at each corner of through hole 21A.

[0024] 3 and 4, a substantially ring-shaped stopper 23 is removably attached to each end of the shaft portion 15B of the gauge shaft 15. The stopper 23 is provided at one axially outer end with a wall portion 23B having a substantially triangular through-hole 23A formed therein, through which each gauge 15A can be inserted and into which the shaft portion 15B is coaxially fitted relative to the stopper 23. The outer diameter of the stopper 23 is approximately the same as the inner diameter of the cylindrical motor shaft 12A.

[0025] Further, stopper 23 has a flat surface 23C formed on a portion of its outer periphery. This flat surface 23C has a small through-hole threaded therein. Stopper 23 is fixed to shaft portion 15B by threading a set screw (not shown) into the through-hole. As shown in FIG. 3, an annular retaining rib 12E is provided at a predetermined axial position on the inner periphery of cylindrical motor shaft 12A. Stopper 23 is attached to the upper end of shaft portion 15B of gauge shaft 15 and comes into contact with this rib from above.

[0026] Therefore, by attaching a stopper 23 to the upper end of the shaft portion 15B of the gauge shaft 15 and placing it inside the motor shaft 12A, it is possible to prevent the gauge shaft 15 from falling out of the through hole 21A of the support plate 21 and also to prevent the gauge shaft 15 from tilting relative to the motor shaft 12A.

[0027] As shown in FIG. 3, when a stopper 23 attached to the upper end of the shaft portion 15B of the gauge shaft 15 contacts the retaining rib 12E, the lower gauge 15A of the gauge shaft 15 protrudes axially outward beyond the lower end surface of the guide 17. As shown in FIGS. 3 and 4, a compression coil spring 25 is inserted into the shaft portion 15B between the support plate 21 and the stopper 23 attached to the lower end of the shaft portion 15B of the gauge shaft 15, biasing the gauge shaft 15 downward. Therefore, when the tip of the guide 17 contacts the seating surface W1 of the workpiece W, the gauge shaft 15 is biased toward the seating surface W1, and the lower gauge 15A is pressed against the seating surface W1. The compression coil spring 25 is an example of a biasing member.

[0028] [Outline of screw tightening shaft 27] Furthermore, the robot tool 11 may have a screw tightening shaft 27 attached to the motor shaft 12A instead of the gauge shaft 15. The schematic configuration of the screw tightening shaft 27 will be described with reference to Fig. 6. Fig. 6 is a perspective view showing an example of the screw tightening shaft 27. The screw tightening shaft 27 is an example of a shaft member.

[0029] 6, the screw tightening shaft 27 has a shaft 27B with a hexagonal cross section that is the same as the cross-sectional dimensions of the shaft 15B, and a pair of bits 27A for tightening the screw that are coaxially provided at both ends of the shaft 27B. The diameter of the base end side of the bit 27A is set to be smaller than the diameter of the inscribed circle of the cross section of the shaft 27B.

[0030] Therefore, by fitting the shaft portion 27B of the screwed shaft 27 into the through-hole 21A of the support plate 21, the screwed shaft 27 can move up and down within the motor shaft 12A and is housed coaxially. Furthermore, because each corner of the hexagonal cross-section of the shaft portion 27B is positioned within each of the relief grooves 21B, it is possible to prevent each corner of the shaft portion 27B from hitting the inner circumferential surface of the through-hole 21A and becoming unable to insert it. Furthermore, by attaching a stopper 23 to the upper end of the shaft portion 27B of the screwed shaft 27 and positioning it within the motor shaft 12A, it is possible to prevent the screwed shaft 27 from falling out of the through-hole 21A of the support plate 21 and also to prevent the screwed shaft 27 from tilting.

[0031] Furthermore, when the stopper 23 attached to the upper end of the shank 27B of the screw tightening shaft 27 comes into contact with the retaining rib 12E, the tip of the screw that engages with the bit 27A on the lower side of the screw tightening shaft 27 protrudes axially outward beyond the lower end surface of the guide 17. Furthermore, a compression coil spring 25 is inserted into the shank 27B between the stopper 23 attached to the lower end of the shank 27B of the screw tightening shaft 27 and the support plate 21, and urges the screw tightening shaft 27 downward.

[0032] Therefore, when the tip of the guide 17 comes into contact with the seating surface W1 of the workpiece W, the screw tightening shaft 27 is urged toward the seating surface W1, and the screw engaged with the lower bit 27A is pressed against the seating surface W1. Furthermore, with the screw engaged with the lower bit 27A fitted into the screw hole W2 in the seating surface W1, the controller 102 rotates the motor shaft 12A of the motor 12 to rotate the screw tightening shaft 27. As a result, the screw engaged with the lower bit 27A is tightened into the screw hole W2 in the seating surface W1.

[0033] [Fitting work] Next, an example of a fitting operation of fitting the gauge 15A of the robot tool 11 into the screw hole W2, which is executed by the controller 102 that controls the robot 100 configured as described above, will be described with reference to FIGS.

[0034] FIG. 7 is a diagram illustrating a first step of the fitting operation in which the gauge shaft 15 is fitted into the screw hole W2 using the robot tool 11. FIG. 8 is a diagram illustrating a second step of the fitting operation in which the gauge shaft 15 is fitted into the screw hole W2 using the robot tool 11. FIG. 9 is a diagram illustrating a third step of the fitting operation in which the gauge shaft 15 is fitted into the screw hole W2 using the robot tool 11. FIG. 10 is a diagram illustrating a fourth step of the fitting operation in which the gauge shaft 15 is fitted into the screw hole W2 using the robot tool 11. FIG. 11 is a diagram illustrating a fifth step of the fitting operation in which the gauge shaft 15 is fitted into the screw hole W2 using the robot tool 11.

[0035] [1st step] 7, the controller 102 first moves the robot arm 101 to align the Z-axis direction, which is parallel to the motor shaft 12A of the robot tool 11, with the vertical direction. Then, the controller 102 moves the robot arm 101 to move the gauge shaft 15 housed in the motor shaft 12A of the robot tool 11 directly above the screw hole W2 of the workpiece W, that is, above the screw hole W2 in the Z-axis direction. For example, the controller 102 moves the robot arm 101 to move the robot tool 11 in the direction of arrow 31.

[0036] At this time, the alignment of the gauge axis 15 of the robot tool 11 with the screw hole W2 is performed using image recognition or a prior teaching operation. Between the gauge axis 15 of the robot tool 11 and the screw hole W2, there may be a deviation in the position or angle of the bearing surface W1 due to variations in the supply position of the workpiece W or errors in image recognition. In other words, the gauge axis 15 of the robot tool 11 and the screw hole W2 are not necessarily directly opposite each other. Furthermore, for example, as shown in FIG. 7, the bearing surface W1 may be inclined with respect to the horizontal plane.

[0037] [Second process] 8, the controller 102 moves the robot arm 101 to move the robot tool 11 in the negative direction of the Z axis, i.e., in the direction of arrow 32. When the controller 102 detects via the force sensor 16 a moment M acting on the guide 17 from the seating surface W1, it determines that a part of the tip of the guide 17 of the robot tool 11 has come into contact with the seating surface W1, and stops the robot arm 101. The controller 102 also detects via the force sensor 16 moment components MX and MY, which have rotation axes on the X and Y axes and act on the guide 17 from the seating surface W1.

[0038] [3rd step] 9, the controller 102 moves the robot arm 101 while detecting the moment components MX and MY via the force sensor 16 so that the moment components MX and MY that the guide 17 receives from the seat surface W1 become approximately zero. For example, the controller 102 rotates the robot tool 11 in the direction of arrow 33.

[0039] As a result, the controller 102 can bring the entire tip of the guide 17 into contact with the seating surface W1. Also, the gauge 15A on the lower side of the gauge shaft 15 is urged downward by the compression coil spring 25 and pressed against the seating surface W1. Also, the gauge shaft 15 is set to be perpendicular to the seating surface W1, that is, parallel to the screw hole W2.

[0040] [4th step] 10, the controller 102 moves the robot arm 101 to slide the guide 17 on the seat W1 in the direction of arrow 34, for example, while keeping the entire tip of the guide 17 in contact with the seat W1, to search for the screw hole W2. Specifically, the controller 102 detects via the force sensor 16 that a force F1 equal to or greater than a predetermined first threshold has been generated, thereby determining that the tip of the gauge 15A has reached the screw hole W2.

[0041] [5th ​​step] 11, when the controller 102 detects that the tip of the gauge 15A has reached the screw hole W2, it stops the movement of the robot arm 101. As a result, the gauge 15A is fitted into the screw hole W2 by the biasing force of the compression coil spring 25. Thereafter, the controller 102 moves the robot arm 101 to slightly slide the tip of the guide 17 while keeping the entire tip of the guide 17 in contact with the seat surface W1.

[0042] Then, when the controller 102 detects a force F2 equal to or greater than a predetermined second threshold via the force sensor 16, it determines that the gauge 15A has fitted into the screw hole W2 and stops the robot arm 101. Thereafter, the controller 102 operates the robot arm 101 to move the robot tool 11 in the positive direction of the Z axis, removes the gauge 15A from the screw hole W2, and ends the fitting operation.

[0043] [Screw tightening work] Next, an example of a screw tightening operation in which a screw is tightened into a screw hole W2 using the screw tightening shaft 27 of the robot tool 11, which is executed by the controller 102 that controls the robot 100 configured as described above, will be described. First, in the robot tool 11 shown in FIG. 7, the screw tightening shaft 27 is set in place of the gauge shaft 15. Then, the screw head of the screw is engaged with the bit 27A on the lower side of the screw tightening shaft 27. Then, the controller 102 operates the robot arm 101 to move the screw tightening shaft 27 of the robot tool 11 upward in the Z-axis direction of the screw hole W2 of the workpiece W.

[0044] Next, the controller 102 moves the robot arm 101 in the negative direction of the Z axis until a part of the tip of the guide 17 of the robot tool 11 comes into contact with the seating surface W1 (see FIG. 8).The controller 102 then moves the robot arm 101 while detecting the moment components MX and MY via the force sensor 16 so that the moment components MX and MY that the guide 17 receives from the seating surface W1 become approximately zero (see FIG. 9).

[0045] As a result, the controller 102 can bring the entire tip of the guide 17 into contact with the seating surface W1. The screw engaged with the lower bit 27A of the screw tightening shaft 27 is urged downward by the compression coil spring 25 and pressed against the seating surface W1. The screw engaged with the screw tightening shaft 27 and the bit 27A is set to be perpendicular to the seating surface W1, that is, parallel to the screw hole W2.

[0046] Next, the controller 102 moves the robot arm 101 to slide the guide 17 over the seating surface W1 while keeping the entire tip of the guide 17 in contact with the seating surface W1, thereby searching for the screw hole W2. Specifically, the controller 102 detects via the force sensor 16 that a force F1 equal to or greater than a predetermined first threshold has been generated, thereby detecting that the tip of the screw engaged with the bit 27A has reached the screw hole W2 (see FIG. 10).

[0047] Then, when the controller 102 detects that the tip of the screw engaged with the bit 27A has reached the screw hole W2, it stops the movement of the robot arm 101. Next, the controller 102 drives the motor 12 to rotate the motor shaft 12A, which in turn rotates the screw tightening shaft 27 via the support plate 21. As a result, the screw engaged with the bit 27A on the lower side of the rotating screw tightening shaft 27 is urged toward the screw hole W2 by the urging force of the compression coil spring 25 and is tightened into the screw hole W2. Thereafter, after stopping the motor 12, the controller 102 moves the robot arm 101 to move the robot tool 11 in the positive direction of the Z axis, thereby completing the screw tightening operation.

[0048] As described above in detail, in the robot tool 11 according to this embodiment, even if there is a slight angular misalignment of the seating surface W1, the force sensor 16 can be used to reduce the moment M that the tip of the guide 17 receives from the seating surface W1 to approximately zero, thereby making the gauge shaft 15 or the screw tightening shaft 27 perpendicular to the seating surface W1. As a result, by sliding the tip of the guide 17 on the seating surface W1 via the tip of the robot arm 101, it becomes possible to search for the screw hole W2 with the gauge shaft 15 or the screw tightening shaft 27. Then, by detecting using the force sensor 16 that the tip of the screw or gauge 15A has reached the screw hole, the screw or gauge 15A and the screw hole W2 can be aligned.

[0049] Furthermore, in the robot tool 11, the motor 12, the guide 17, and the force sensor 16 can be attached to the base plate 13, which allows for a simple configuration and reduces manufacturing costs.

[0050] Furthermore, in the robot tool 11, when the entire tip of the guide 17 comes into contact with the seating surface W1, the gauge shaft 15 or the screw tightening shaft 27 is urged toward the seating surface W1 by the compression coil spring 25. As a result, the gauge 15A or the screw comes into contact with the screw hole W2 while being urged toward the seating surface W1, and the force sensor 16 can detect that the gauge 15A or the screw has been aligned with the screw hole W2.

[0051] Furthermore, by inserting the shaft portions 15B, 27B of the gauge shaft 15 or the screw tightening shaft 27 into the through-hole 21A of the support plate 21, it is possible to accommodate it coaxially with the motor shaft 12A so that it can be raised and lowered. Furthermore, the rotation of the motor shaft 12A can be reliably transmitted to the gauge shaft 15 or the screw tightening shaft 27. Furthermore, the relief grooves 21B, which have a semicircular cross section and are formed at each corner of the through-hole 21A, prevent the corners of the shaft portions 15B, 27B of the gauge shaft 15 or the screw tightening shaft 27 from hitting the inner circumferential surface of the through-hole 21A and becoming unable to be inserted. Furthermore, the gauge shaft 15 or the screw tightening shaft 27 can be raised and lowered smoothly.

[0052] Furthermore, stoppers 23 provided on the upper ends of the shaft portions 15B, 27B of the gauge shaft 15 or the screw-fastening shaft 27 come into contact from above with retaining ribs 12E formed on the inner circumferential surface of the shaft hole of the motor shaft 12A. This prevents the gauge shaft 15 or the screw-fastening shaft 27 from tilting relative to the motor shaft 12A and prevents the gauge shaft 15 or the screw-fastening shaft 27 from falling off the motor shaft 12A.

[0053] [Variation 1] In the above embodiment, the tip of the guide 17 is formed on a plane perpendicular to the axial direction of the motor shaft 12A, but it may also be formed on a plane obliquely intersecting the axial direction of the motor shaft 12A. This allows the entire tip of the guide 17 to contact the seating surface W1, so that the gauge shaft 15 or the screw tightening shaft 27 can be set parallel to the screw hole W2, even for a screw hole W2 that is formed at an angle relative to the seating surface W1 of the workpiece W. As a result, the gauge 15A or the screw can be fitted into the screw hole W2 that is formed at an angle relative to the seating surface W1 of the workpiece W, by setting the entire tip of the guide 17 in parallel to the screw hole W2.

[0054] [Variation 2] Also, for example, the gauge shaft 15 may have the gauge 15A only on one end side of the shaft portion 15B. Also, the screw tightening shaft 27 may have the bit 27A only on one end side of the shaft portion 27B.

[0055] [Variation 3] Alternatively, for example, each gauge 15A may have a mounting screw at one end that is thinner than the outer diameter of the gauge 15A and be screwed into a mounting screw hole formed at both ends of the shaft portion 15B. This allows the gauge 15A to be easily replaced according to the screw hole W2. Also, each bit 27A may have a mounting screw at the base end that is thinner than the outer diameter of the bit 27A and be screwed into a mounting screw hole formed at both ends of the shaft portion 27B. This allows the bit 27A to be easily replaced according to the screw that is screwed into the screw hole W2.

[0056] [Variation 4] Also, for example, it is not necessary to provide the retaining rib 12E inside the motor shaft 12A. In this case, the stopper 23 fixed to the upper end of the shaft portion 15B of the gauge shaft 15 comes into contact with the support plate 21, preventing it from coming out of the through-hole 21A. Also, the stopper 23 fixed to the upper end of the shaft portion 27B of the screw-fastening shaft 27 comes into contact with the support plate 21, preventing it from coming out of the through-hole 21A.

[0057] [Variation 5] Also, for example, a thread that can be screwed into the screw hole W2 may be formed on the outer peripheral surface of the gauge 15A of the gauge shaft 15. As a result, as shown in Fig. 10, when it is detected that the tip of the gauge 15A has reached the screw hole W2 with the entire tip of the guide 17 in contact with the seating surface W1, the movement of the robot arm 101 is stopped. Next, the controller 102 drives the motor 12 to rotate the motor shaft 12A, thereby rotating the gauge shaft 15 via the support plate 21.

[0058] As a result, the thread cut into the outer peripheral surface of the gauge 15A on the lower side of the rotating gauge shaft 15 is urged toward the screw hole W2 by the urging force of the compression coil spring 25 and is screwed into this screw hole W2 (see FIG. 11). After that, the controller 102 stops the motor 12 and then moves the robot arm 101 to slightly slide the tip of the guide 17 while keeping the entire tip end in contact with the seat surface W1.

[0059] Then, when the controller 102 detects a force F2 equal to or greater than a predetermined second threshold via the force sensor 16, it determines that the gauge 15A has been screwed into the screw hole W2 and stops the robot arm 101. Thereafter, the controller 102 may reverse the rotation of the motor 12 to remove the gauge 15A from the screw hole W2, and then move the robot arm 101 to move the robot tool 11 in the positive direction of the Z axis, thereby completing the fitting operation. This allows the controller 102 to inspect the screw hole W2 of the workpiece W using the gauge 15A.

[0060] [Additional Notes] The present disclosure is not limited to the above-described embodiments and each modified example, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the embodiments and each modified example are also included in the technical scope of the present disclosure.

[0061] [Note] The robot tool of the first embodiment comprises a shaft member having at least one end provided with a gauge for inspecting screw hole diameter or a bit for tightening or loosening screws, a motor that accommodates the shaft member so that it can be raised and lowered within a cylindrical motor shaft, a cylindrical guide that is arranged so that the shaft member can be inserted and whose tip contacts a seating surface, and a force sensor that detects the moment that the guide receives from the seating surface when a portion of the tip of the guide contacts the seating surface.

[0062] According to the robot tool of the first aspect, even if the angle of the seating surface is slightly misaligned, the force sensor can be used to virtually eliminate the moment the guide tip receives from the seating surface, thereby setting the shaft member at a predetermined angle relative to the seating surface, for example, perpendicular to it. As a result, the tip of the guide can be slid over the seating surface via the tip of the robot arm, allowing the shaft member to search for a screw hole. Then, the force sensor can be used to detect when the tip of the screw or gauge has reached the screw hole, allowing the screw or gauge to be aligned with the screw hole.

[0063] A second aspect may be the robot tool of the first aspect, further comprising a base plate having a first through-hole into which the motor shaft is inserted, the motor being arranged on a surface opposite the seat side, the guide being attached to the surface of the base plate facing the seat side, and the force sensor being attached between the surface of the base plate opposite the seat side and the tip of a robot arm.

[0064] According to the robot tool of the second aspect, the motor, guide, and force sensor can be attached to the base plate, which simplifies the configuration and reduces manufacturing costs.

[0065] A third aspect is a robot tool according to the first or second aspect, which may further include a biasing member that biases the shaft member toward the seating surface when the tip of the guide contacts the seating surface.

[0066] According to the robot tool of the third aspect, when the tip of the guide contacts the seating surface, the shaft member is urged toward the seating surface by the urging member, and as a result, the gauge or screw contacts the screw hole while being urged toward the seating surface, so that the force sensor can detect that the gauge or screw has been aligned with the screw hole.

[0067] A robot tool of a fourth aspect is a robot tool of any one of the first to third aspects, wherein the shaft member has a shaft portion having a polygonal cross section, the motor shaft has a support plate attached to the end face on the seat side, and the support plate has a second through hole formed in the center coaxially with the motor shaft, through which the shaft portion is inserted so as to be slidable in the longitudinal direction and which supports the shaft portion so as not to rotate.

[0068] According to the fourth aspect of the robot tool, by inserting the shaft portion of the shaft member into the second through hole of the support plate, it can be accommodated coaxially with the motor shaft so that it can be raised and lowered, and the rotation of the motor shaft can be reliably transmitted to the shaft member.

[0069] A fifth aspect is the robot tool of the fourth aspect, wherein the second through hole is formed in the polygonal shape in front view into which the shaft portion is inserted, and may have a relief groove recessed radially outward in a U-shaped cross section from each corner of the inner circumferential surface over the entire thickness of the support plate.

[0070] According to the robot tool of the fifth aspect, the U-shaped cross-section relief grooves formed at each corner of the second through hole prevent the corners of the shaft portion of the shaft member from being pressed against the second through hole and being unable to slide, allowing the shaft member to be raised and lowered smoothly. [Explanation of symbols]

[0071] 11: robot tool, 12: motor, 12A: motor shaft, 12E: retaining rib, 13: base plate, 13A, 21A: through hole, 15: gauge shaft, 15A: gauge, 15B, 27B: shaft, 16: force sensor, 17: guide, 21: support plate, 21B: relief groove, 23: stopper, 25: compression coil spring, 27: screw tightening shaft, 27A: bit

Claims

1. a shaft member provided at least at one end with a gauge for inspecting the diameter of a screw hole or a bit for tightening or loosening a screw; a motor that accommodates the shaft member in a cylindrical motor shaft so that the shaft member can be raised and lowered; a cylindrical guide that is arranged so that the shaft member can be inserted therethrough and whose tip contacts a seat surface; a force sensor that detects a moment that the guide receives from the seating surface when a portion of the tip of the guide comes into contact with the seating surface; Robotic tools.

2. the motor is disposed on a surface opposite to the seat surface side, and a base plate having a first through hole into which the motor shaft is inserted is provided; The guide is attached to the surface of the base plate on the seat side, The force sensor is attached between a surface of the base plate opposite to the seat surface side and a tip end of the robot arm. The robotic tool of claim 1 .

3. a biasing member that biases the shaft member toward the seating surface when the tip of the guide contacts the seating surface, A robot tool according to claim 1 or 2.

4. The shaft member has a shaft portion having a polygonal cross section, The motor shaft A support plate is attached to the end surface on the seat side, The support plate is a second through-hole formed in the center coaxially with the motor shaft, into which the shaft portion is inserted so as to be slidable in the longitudinal direction and which supports the shaft portion so as not to rotate; A robot tool according to claim 1 or 2.

5. The second through hole is The support plate has a recess groove formed in the polygonal shape in front view into which the shaft portion is inserted, the recess groove having a U-shaped cross section recessed radially outward from each corner of the inner circumferential surface over the entire thickness of the support plate. The robotic tool of claim 4 .

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