JP5918646B2 - robot - Google Patents

Description

  The present invention relates to an industrial robot.

  Today, arc welding robots having an arc welding torch attached to the tip of a six-axis vertical articulated robot are widely used in many industrial fields. This 6-axis vertical articulated robot has a turning base (basic first axis) that turns around a vertical axis on a base, and a lower arm (basic second axis) that is attached to the turning base and swings back and forth. And an upper arm (basic third axis) attached to the tip of the lower arm and swinging in the vertical direction, and a wrist portion (wrist first axis to wrist first) attached to the tip of the upper arm and having three degrees of freedom. 3 axes). If an arc welding torch is attached to the tip of the wrist, the arc welding torch can take an arbitrary posture at an arbitrary position, so that arc welding can be performed freely.

  FIG. 8 is a side view of a conventional arc welding robot. In the figure, reference numeral 3 denotes a lower arm, which is pivotally supported by a turning base (not shown) and swings in the front-rear direction. Reference numeral 4 denotes an upper arm, which is rotatably supported around a U axis (an axis perpendicular to the paper surface) at the tip of the lower arm 3 and swings in the vertical direction. Reference numeral 5 denotes a wrist attached to the tip of the upper arm. The wrist 5 includes a body 6 that rotates about the R axis extending in the length direction of the upper arm 3, and a B axis that is supported by the tip of the body 6 and is orthogonal to the R axis (an axis perpendicular to the paper surface). An oscillating body 7 that oscillates around and a rotator 8 that rotates at the tip of the oscillating body 7 and rotates around the T-axis orthogonal to the B-axis. Reference numeral 9 denotes a welding torch, which is fixed to the rotating portion 8 via a torch clamp 10. Reference numeral 11 denotes a wire feeding device fixed on the upper arm 2, which is a device that pulls out a welding wire from a wire storage device (for example, a wire reel) (not shown) and pushes it toward the welding torch 9. A conduit cable 12 connects the welding torch 9 and the wire feeder 11. The conduit cable 12 is a bundle of a welding current supply cable and a shield gas supply hose around a protective tube for feeding a welding wire to the welding torch 9.

  However, in the conventional arc welding robot, when the swinging body 7 is swung around the B axis and the welding torch 9 is swung up and down with respect to the upper arm 4, the conduit cable 12 is bent, and the welding wire There was a problem that the feeding was hindered. There is also a problem that the conduit cable 12 is buckled due to a compressive force. Further, when the rotating body 8 is rotated around the T axis, there is a problem that the conduit cable 12 is wound around the wrist portion 5 and the upper arm 4. In order to improve these problems, the conduit cable 12 is bridged over the upper arm 4 so as to draw a large arch as shown in FIG. 8, and the movement of the welding torch 9 is absorbed by the deformation of the arch. However, since the conduit cable 12 depicting a large arch causes interference with the workpiece and peripheral devices, the arch cannot be enlarged unnecessarily, and a complete solution cannot be achieved. Therefore, the present invention provides a robot that can further suppress interference between cables and peripheral devices.

In order to solve the above problems, a robot of the present invention includes a base, an arm provided on the base, and a body bottom connected to the arm so as to rotate about a first axis with respect to the arm. On the extension line of the first shaft, a trunk having a first extension part extending from the bottom part of the fuselage, a second extension part arranged with a gap from the first extension part, and A second opening that is provided at the bottom of the body and is attached to the front end of at least one of the passage opening through which the cable can be inserted, the first extension portion, and the second extension portion, and is orthogonal to the first axis. An oscillating body that oscillates about an axis, and a position that is offset with respect to an extension line of the first shaft, and between the tip of the first and second extending portions and the bottom of the body. is supported on the body at the position of the body bottom close, the oscillator oscillating the second axis And a rotating body capable of holding an end effector supported by the swinging body and connected to a cable so as to rotate around a third axis orthogonal to the second axis. Yes.

  According to the present invention, it is possible to eliminate interference with a cable even when a rocking body or a rotating body is operated largely.

1 is a side view of an industrial robot showing a first embodiment of the present invention. It is a three-dimensional view of the industrial robot shown in FIG. It is a plane sectional view of the upper arm of the industrial robot shown in FIG. It is a three-dimensional view of an intermediate axis. It is a side view of the wrist part of the industrial robot which shows the 2nd Example of this invention. FIG. 6 is a plan sectional view showing an internal mechanism of the wrist shown in FIG. 5. It is a three-view figure of the wrist part of the industrial robot which shows the 3rd Example of this invention. It is a side view of the industrial robot which shows a prior art.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view of an industrial robot showing a first embodiment of the present invention. In the figure, reference numeral 1 denotes an industrial robot base. A turning base 2 is mounted on the base 1 so as to be rotatable about a vertical axis (S axis). A lower arm 3 is pivotally supported about a horizontal axis (L axis) on the turning base 2 and swings in the front-rear direction. Move. The upper arm 4 is pivotally supported around the horizontal axis (U axis) at the upper end of the lower arm 3 and swings in the vertical direction. Reference numeral 5 denotes a wrist attached to the tip of the upper arm 4. The wrist portion 5 includes a trunk 6 that is rotatably mounted around a central axis (R axis: wrist first axis) in the length direction of the upper arm 4, and an axis (B axis) that is orthogonal to the R axis at the tip of the trunk 6. : A oscillating body 7 that is pivotally supported around the wrist second axis) and a rotator 8 that rotates around the rotation axis (T-axis: wrist third axis) at the tip of the oscillating body 7.

  9 is a welding torch attached to the rotating body 8, and 11 is a wire feeding device fixed to the rear end of the upper arm 4. The wire feeder 11 is supplied with a welding wire from a wire reel (not shown), and feeds the welding wire to the welding torch 9 through the conduit cable 12. The conduit cable 12 extends in the side of the upper arm 4 in parallel with the R axis and is drawn into the upper arm 4 from an entrance 21 that opens to the side of the upper arm 4. The route of the conduit cable 12 from the inside of the upper arm 4 to the welding torch 9 will be described later. The conduit cable 12 is protected by being passed through a protective tube in which a coil spring is covered with a resin.

FIG. 2 is a three-dimensional view of the industrial robot shown in FIG. The body 6 of the wrist portion 5 has a substantially U-shaped bifurcated shape in plan view, and includes two members 22 and 23 extending in parallel to the R axis. The rocking body 7 is sandwiched between the members 22 and 23 and supported by both ends. The conduit cable 12 that enters the upper arm 4 from the entrance 21 exits again from the passage opening 25 that opens to the U-shaped bottom 24 of the body 6, passes through the space between the members 22 and 23, It extends to the rocking body 7. The passage opening 25 is an opening centered on the R axis, and the conduit cable 12 is arranged along the R axis from the passage opening 25 toward the rocking body 7 (so that the center of the conduit cable 12 and the R axis coincide). Established.

FIG. 3 is a plan sectional view of the upper arm 4 of the industrial robot shown in FIG. 1 cut along the line AA ′ of FIG. In the figure, reference numeral 31 denotes a motor mounted in the upper arm 4 with the center of the rotation axis coinciding with the R axis, that is, concentric with the R axis. The motor 31 is connected via a speed reducer 32 and an intermediate shaft 33. The body 6 of the wrist 5 is rotated around the R axis. The intermediate shaft 33 is rotatably supported on the upper arm 4 by a bearing 34 and a bearing 35. The intermediate shaft 33 is supported by the bearing 34 and connected to the speed reducer 32, the hollow cylindrical portion 37 supported by the bearing 35 and connected to the body 6, and the rotation center (R axis). It consists of a connecting portion 38 that connects the annular portion 36 and the hollow cylindrical portion 37 at an offset position, and has a crankshaft shape as a whole (see FIG. 4).

  Reference numeral 39 denotes in-machine wiring. The in-machine wiring 39 is a power line for driving a motor (described later) that is mounted in the body 6 and drives the rocking body 7 and the rotating body 8, and is drawn into the upper arm 4 from the lower arm 3. Clamped to the upper arm 4 at 39a. The in-machine wiring 39 extends from the point 39a to a point 39b by drawing an arc around the R axis, and further forms a U-shaped bent portion from the point 39b to the point 39c. Then, an annular portion is formed again around the R axis and clamped to the annular portion 36 of the intermediate shaft 33 at a point 39d. Note that the holding structure of the in-flight wiring 39 from 39a to 39d is the registered utility model No. 2117576 (actual fairness 7-39575), and the applicant of this application holds the right.

  The in-machine wiring 39 extends from the point 39d along the connecting portion 38 of the intermediate shaft 33 (not shown, but the in-machine wiring 39 is appropriately secured to the connecting portion 38). Avoiding the center (R-axis), it enters the body 6 through a groove provided on the outer periphery of the hollow portion. The conduit cable 12 enters the upper arm 4 from the entrance 21 opened to the side surface of the upper arm 4, and passes through the hollow portion at the center of the hollow cylindrical portion 37 of the intermediate shaft 33 and the passage port 25 of the body 6 to the outside. Get out. The hollow part and the passage opening are cylinders centered on the R axis, and the conduit cable 12 is drawn straight out along the R axis. Since the conduit cable 12 is at the center of the R-axis and the in-machine wiring 39 is away from the center of the R-axis, when the fuselage 6 rotates around the R-axis, the in-machine wiring 39 is routed around the conduit cable 12. Orbit like a satellite. For this reason, interference between the in-machine wiring 39 and the conduit cable 12 does not occur. Here, the interference between the conduit cable 12 and the connecting portion 38 of the intermediate shaft 33 when the intermediate shaft 33 is rotated around the R-axis becomes a problem. Since bending is allowed, the intermediate shaft 33 can be rotated ± 180 ° around the R axis from the illustrated position. Therefore, this interference is not a practical problem.

  FIG. 5 is a side view of the wrist portion of an industrial robot showing a second embodiment of the present invention. For convenience of explanation, the cover on the right side of the body 6 of the wrist portion 5 is removed and the internal mechanism can be seen. It draws like so. In the figure, 51 is a motor for driving the oscillating body 7, which is mounted in the body 6 in a lateral direction, that is, perpendicular to the R axis and parallel to the B axis. A pulley 52 is attached to the output shaft of the motor 51. A speed reducer 53 is connected to the rocking body 7 and is attached to the front end of the body 6. A pulley 54 is attached to the input shaft of the speed reducer 53, and a timing belt 55 is wound between the pulley 54 and the pulley 52. That is, the power of the motor 51 is transmitted to the speed reducer 53 via the belt pulley mechanism, and the oscillating body 7 is rotationally driven around the B axis. Reference numeral 56 denotes a motor that drives the rotating body 8, and is attached to the inside of the body 6 in the horizontal direction in the same manner as the motor 51. The power of the motor 56 drives the rotating body 8 via another belt pulley mechanism (not shown) arranged on the left side (the back side of the paper surface) of the body 6. The motor 51 and the motor 56 are attached at positions offset downward from the center of the R axis. This is to avoid interference with the conduit cable 12 extending along the R axis.

  FIG. 6 is a cross-sectional plan view showing the internal mechanism at the tip of the wrist of the industrial robot shown in FIG. 5. In FIG. 6, the rocking body 7 is rotated by 90 ° about the B axis, Is horizontal, that is, the R axis and the T axis overlap each other. In addition, since the same component as FIG. 5 was attached | subjected, the description is abbreviate | omitted. Reference numeral 61 denotes a belt which transmits the power of a rotating body driving motor (corresponding to the motor 56 of FIG. 5 but not shown) to the pulley 62. A bevel gear 63 is attached to the pulley 62. Reference numeral 64 denotes a transmission shaft that is pivotally supported by the oscillator 7 in parallel to the T axis. Bevel gears 65 and 66 are attached to both ends of the transmission shaft 64, and the bevel gear 65 meshes with the bevel gear 63. Reference numeral 67 denotes a bevel gear attached to the rotating body 8. The bevel gear 67 meshes with the bevel gear 66. In this way, the power of the rotating body driving motor is transmitted to the rotating body 8. The rotating body 8 has a cylindrical hollow portion centered on the T axis, and the welding torch 9 passes through the hollow portion. A conduit cable 12 is connected to the end of the welding torch 9 that penetrates the rotating body 8. The conduit cable 12 is disposed concentrically with the R-axis in a space between the members 22 and 23 of the trunk 6 having a bifurcated shape. The belt pulley mechanism for driving the oscillating body is disposed inside the member 22, and the belt pulley mechanism for driving the rotating body is disposed inside the member 23.

  FIGS. 7A and 7B are three views of an industrial robot showing a third embodiment of the present invention. FIG. 7A is a front view, FIG. 7B is a plan view, and FIG. 7C is a right side view. Since the basic configuration is the same as that of the first and second embodiments shown in FIGS. 1 to 6, the same reference numerals are given to common components and the description thereof is omitted. The oscillating body 7 includes a main body 7 a that supports the rotator 8, two left and right sides (as viewed from the right side) of the main body 7 a, and extends in parallel to the third axis (T axis), that is, the rotation center of the rotator 8. The portions 7b and 7c are provided to form a bifurcated shape. The tips of the portions 7b and 7c are rotatably supported by the left and right members 22 and 23 of the body 6, respectively, and the swinging body 7 is supported by both ends. The conduit cable 12 extends through the space between the members 22 and 23 and the space between the portions 7a and 7b to the rotating body 8 (and to the welding torch attached to the end thereof). Reference numeral 13 denotes a cable support fixed to the portion 7b. The cable support 13 is a plate-like member that blocks between the portions 7b and 7c, and functions as a restraining piece that suppresses the conduit cable 12 from protruding between the portions 7b and 7c. Further, a connecting piece 14 is provided between the member 22 and the member 23 of the body 6 to connect the two, and the conduit cable 12 is prevented from hanging below the body 6. Thus, since the deformation of the conduit cable 12 is suppressed by the cable support 13 and the connecting piece 14, even if the swinging body 7 or the rotating body 8 is operated largely, the conduit cable 12 protrudes greatly from the wrist 5, And no interference with peripheral devices. Further, when the swinging body 7 is swung up right (in a state where it is swung by 180 ° from the state shown in FIG. 7), the conduit cable 12 is deformed so as to protrude above the body 6, but the cable support 13 is deformed. There is also an effect to hold down.

  In the embodiment described above, the swinging body 7 of the wrist portion 5 is pivotally supported at the tip of the body 6 by both ends, but may be attached in a cantilever manner. That is, a structure in which one member 23 of the two members 22 and 23 of the body 6 shown in FIG. 2 is removed and the oscillator 6 is supported by the member 22 in a cantilever manner may be selected.

  In the embodiment, the conduit cable 12 is drawn into the upper arm 4 from the side surface of the upper arm 4. However, if configured as in the following first and second modifications, the conduit cable 12 is connected to the rear of the upper arm. It can extend straight along the R axis from the end to the welding torch.

(Modification 1) A so-called hollow shaft motor and hollow shaft speed reducer having a hollow portion that penetrates the motor 31 and the speed reducer 32 from the anti-load side to the load side, and the conduit cable 12 is moved from the rear end of the upper arm 4 to the motor. It extends straight through the hollow shaft 31 and the hollow shaft of the speed reducer 32 into the intermediate shaft 33 (along the R axis). At this time, the wire feeding device 11 is preferably attached so that the feeding direction of the welding wire coincides with the R axis. Compared with drawing the conduit cable 12 from the side surface of the upper arm 4, this structure is expected to have an effect of reducing the welding resistance of the welding wire because the conduit cable 12 is less bent.

(Modification 2) Since the hollow shaft motor used in Modification 1 is expensive, only the speed reducer 32 is a hollow shaft speed reducer, the motor 31 is offset parallel to the R axis, and the speed reducer 32 is coupled with the belt pulley mechanism. May be combined. In this case, the conduit cable 12 enters the upper arm 4 along the R axis from the rear end of the upper arm 4, passes by the motor 31, and enters the hollow shaft of the speed reducer 32.

  Further, although the arc welding robot is taken up in the description of the embodiments, the present invention is not limited to the arc welding robot. It is possible for all uses such as painting, sealing, polishing, and handling. In other words, the end effector may be a spray gun for painting, a nozzle for sealing, a polishing tool, a mechanical hand, etc., and a cable or the like is a paint hose, a seal material supply hose, an air hose for driving a pneumatic tool, an electric tool It may be a driving power line or the like. In order to describe the arrangement state of the conduit cable 12, expressions such as concentric with the R axis or parallel to the R axis are used, but these expressions do not require geometrical strictness. It goes without saying that a slight width (error) is allowed as long as the object effect of the present invention can be achieved.

1: base, 2: swivel base, 3: lower arm, 4: upper arm, 5: wrist, 6: trunk, 7: swinging body, 8: rotating body, 9: welding torch, 10: torch clamp, 11 : Wire feeding device, 12: Conduit cable, 13: Cable support, 14: Connection piece 21: Entrance, 22, 23: Member, 24: Bottom, 25: Passage, 31: Motor, 32: Reducer, 33 : Intermediate shaft, 34, 35: Bearing 36: Ring portion, 37: Hollow cylindrical portion, 38: Connection portion, 39: In-machine wiring, 51: Motor, 52: Pulley, 53: Reducer, 54: Pulley, 55: Belt: 56: Motor 61: Belt, 62: Pulley, 63, 65, 66, 67: Bevel gear, 64: Transmission shaft

Claims (2)

The base,
An arm provided on the base;
A trunk bottom connected to the arm to rotate about the first axis with respect to the arm, a first extension extending from the trunk bottom, and a gap between the first extension and the arm A fuselage having a second extending portion disposed on the surface;
A passage opening provided at the bottom of the body on the extension line of the first shaft and capable of inserting a cable;
An oscillating body attached to at least one of the first extending portion and the second extending portion and oscillating about a second axis perpendicular to the first axis;
The position is offset with respect to the extension line of the first shaft, and is supported by the body at a position near the body bottom between the tips of the first extension part and the second extension part and the body bottom part. A motor that swings the swinging body around the second axis;
And a rotating body capable of holding an end effector supported by the swinging body and connected to a cable so as to rotate around a third axis orthogonal to the second axis. The robot according to claim 1, wherein the motor that swings the swinging body is mounted substantially parallel to the second axis.

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