JP6539457B2 - Robot joint structure - Google Patents

Description

  The present invention relates to a joint structure of a robot.

  Conventionally, an articulated robot having a plurality of arms is known as an industrial robot. For example, Patent Document 1 describes an articulated robot having a plurality of arms (pivotal members), in which a welding torch for welding is fixed to an arm at the tip end.

  Further, Patent Document 1 proposes a technique in which a section of a part of a power cable for supplying power to a welding torch is disposed inside an arm. Specifically, in the articulated robot of Patent Document 1, the inside of the first arm and the inside of the second arm are communicated by a cylinder. Further, one end side of the power cable is fixed to the first arm. The power cable is drawn into the second arm through the inside of the first arm and the inside of the tubular body. The other end of the power cable is fixed to the second arm. As described above, by arranging the power cable inside each arm at the joint portion between the first arm and the second arm, when the second arm pivots with respect to the first arm, It is possible to prevent the object from being hit or stuck.

JP, 2011-161571, A

  In the robot of Patent Document 1, one end of the power cable is fixed to the first arm, and the other end is fixed to the second arm. Thus, when the second arm pivots relative to the first arm, a twist occurs in the power cable. If such a twist acts repeatedly on the power cable, the power cable may be damaged, which is not preferable.

  The present invention has been made in view of the circumstances of the prior art as described above, and arranges a conductive member such as a power cable or the like inside a rotatable pivoting member while providing a twist on the conductive member. Intended to reduce.

  In order to achieve the above object, a joint structure of a robot according to the present invention is a joint structure of a robot including a stationary side member and a pivoting member rotatable relative to the stationary side member, the pivoting of the robot A communication portion is provided on the rotation axis of the member for communicating the inside of the fixed side member with the inside of the rotation member, and a conductive member is inserted through the communication portion, and the fixed side member and the turn A current collecting member electrically connected to the conductive member is provided on at least one of the moving members, and a cable member is attached to the current collecting member so as to be electrically connected to the conductive member. The conductive member is in contact with the current collecting member so as to slide and rotate.

  According to the present invention, even when the movable member pivots with respect to the fixed side member, the occurrence of twisting in the conductive member can be reduced.

A side view of an articulated robot. Sectional drawing of the joint structure of an articulated robot. FIG. The side view of a current collection member. Sectional drawing of a current collection member.

(Configuration of the embodiment)
An embodiment in which a joint structure of a robot of the present invention is applied to an articulated robot R (hereinafter abbreviated as robot R) for performing arc welding will be described. First, an outline of the robot R will be described.

  As shown in FIG. 1, on the upper part of a base C1 of the robot R, a swivel base C2 is provided so as to be rotatable about a first rotation axis J1. A first arm C3 is provided on an upper portion of the swivel base C2 so as to be pivotable about a second pivot axis J2 orthogonal to the first pivot axis J1. A second arm C4 is provided rotatably at a distal end portion of the first arm C3 about a third rotation axis J3 orthogonal to the second rotation axis J2. A third arm C5 is provided rotatably at a distal end portion of the second arm C4 about a fourth rotational axis J4 orthogonal to the third rotational axis J3.

  As shown in FIG. 1, the fourth arm C6 is provided at the tip of the third arm C5 so as to be rotatable about a fifth rotation axis J5 orthogonal to the fourth rotation axis J4. . At the tip of the fourth arm C6, a fifth arm C7 is provided so as to be rotatable about a sixth rotation axis J6 orthogonal to the fifth rotation axis J5. At the tip end of the fifth arm C7, a tool fixing member C8 is provided rotatably around a seventh rotation axis J7 orthogonal to the sixth rotation axis J6. A welding torch C9 is fixed to the tool fixing member C8 as a working tool, and the welding torch C9 rotates integrally with the tool fixing member C8. The fourth arm C6, the fifth arm C7, and the tool fixing member C8 may be collectively referred to as a wrist assembly. The swivel base C2, the first arm C3 to the fifth arm C7, and the tool fixing member C8 rotate using the servomotor as a drive source.

  As shown in FIG. 1, a first power cable PC1 as a cable member is attached to the outer surface of the swivel base C2 of the robot R. As shown in FIG. One end of the first power cable PC1 is connected to a welding power supply (not shown). The first power cable PC1 is extended along the outer surface of the swivel base C2 and the first arm C3, and the other end is drawn into the inside of the first arm C3.

  As shown in FIG. 1, a second power cable PC2 is attached to the outer surface of the third arm C5 in the robot R. Although not shown in FIG. 1, one end of the second power cable PC2 is connected to the welding torch C9. The second power cable PC2 is extended along the outer surfaces of the third arm C5 and the second arm C4, and the other end is drawn into the inside of the second arm C4. The other end of the first power cable PC1 and the other end of the second power cable PC2 are electrically connected in the first arm C3 and the second arm C4. Therefore, the electric power from the welding power supply is supplied to the welding torch C9 via the first power cable PC1 and the second power cable PC2.

  Next, the connection structure of the first arm C3 and the second arm C4 in the robot R will be described. The first arm C3 is closer to the fixed side (base C1) than the second arm C4, and thus corresponds to a fixed side member in relation to the second arm C4. Further, since the second arm C4 is pivotable with respect to the first arm C3, the second arm C4 corresponds to a pivoting member in relation to the first arm C3.

  As shown in FIG. 2, the first housing 11 of the first arm C3 is formed on the tip end side (upper side in FIG. 2) to have a hollow portion 11a in which the first power cable PC1 etc. can be disposed. . Specifically, the first housing 11 has a bottom wall 12 extending orthogonal to the third rotation axis J3, and a side wall 13 provided upright from the bottom wall 12 to the second arm C4 side. And an upper wall portion 14 connected to the tip of the side wall portion 13 and extending orthogonally to the third rotation axis J3. The hollow portion 11 a of the first housing 11 is partitioned by the bottom wall portion 12, the side wall portion 13, and the upper wall portion 14. Two openings 13 a are formed in the side wall 13 of the first housing 11. A cover member (not shown) is removably attached to each of the openings 13a. A circular through hole 14 a is formed in the upper wall portion 14 of the first housing 11. The center of the through hole 14a is located on the third rotation axis J3. An annular recess 14 b is formed on the upper surface of the upper wall 14 of the first housing 11 so as to surround the through hole 14 a.

  As shown in FIG. 2, the speed reduction mechanism 15 is attached to the upper surface of the upper wall portion 14 of the first housing 11 in the first arm C3. The speed reduction mechanism 15 has a generally cylindrical shape in which a through hole 15a is formed at the center as a whole. The inner diameter of the through hole 15 a of the reduction gear mechanism 15 is smaller than the inner diameter of the through hole 14 a in the upper wall portion 14 of the first housing 11. The center of the through hole 15a of the reduction gear mechanism 15 is located on the third rotation axis J3. An annular convex portion 15 b is formed on the lower surface of the speed reduction mechanism 15 so as to surround the through hole 15 a. The convex portion 15b of the speed reduction mechanism 15 is formed to have a dimension corresponding to the concave portion 14b of the upper wall portion 14 in the first arm C3. Then, the convex portion 15b of the reduction gear mechanism 15 is fitted to the concave portion 14b of the upper wall portion 14 of the first arm C3, whereby the reduction gear mechanism 15 and the first arm C3 are positioned relative to each other. An annular recess 15 c is formed on the top surface of the speed reduction mechanism 15 so as to surround the through hole 15 a. The reduction gear mechanism 15 incorporates a plurality of gears (not shown), and decelerates the rotational speed input to the gears at a predetermined reduction ratio and outputs it. And a part by the side of the 1st arm C3 of reduction gear mechanism 15 rotates with the 1st arm C3, and the other part by the side of the 2nd arm C4 rotates with the 2nd arm. In addition, in FIG. 2, the reduction mechanism 15 is simplified and shown in figure as an integral member.

  As shown in FIG. 2, the second housing 31 of the second arm C <b> 4 is attached to the front end side (upper side in FIG. 2) of the speed reduction mechanism 15. The second housing 31 of the second arm C4 is formed on the base end side (lower side in FIG. 2) so as to have a hollow portion 31a in which the second power cable PC2 and the like can be disposed. Specifically, the second housing 31 extends from the bottom wall 32 to the distal end of the second arm C4 such that the bottom wall 32 extends perpendicularly to the third pivot axis J3 on the base end side of the second housing 31. It has a side wall portion 33 erected to the side, and an upper wall portion 34 connected to the tip end side of the side wall portion 33 and extending so as to be orthogonal to the third rotation axis J3. The hollow portion 31 a of the second housing 31 is partitioned by the bottom wall portion 32, the side wall portion 33, and the upper wall portion 34.

  As shown in FIG. 2, a circular through hole 32 a is formed in the bottom wall portion 32 of the second housing 31. The inner diameter of the through hole 32 a is the same as the inner diameter of the through hole 15 a of the reduction gear mechanism 15. The center of the through hole 32a in the bottom wall 32 of the second housing 31 is located on the third rotation axis J3. An annular convex portion 32 b is formed on the lower surface of the bottom wall portion 32 of the second housing 31 so as to surround the through hole 32 a. The convex portion 32 b is formed to have a dimension corresponding to the concave portion 15 c of the speed reduction mechanism 15. Then, the convex portion 32 b of the bottom wall portion 32 of the second housing 31 is fitted into the concave portion 15 c of the speed reduction mechanism 15, whereby the second arm C 4 and the speed reduction mechanism 15 are positioned with each other. Two openings 33 a are formed in the side wall 33 of the second housing 31. A cover member (not shown) is detachably attached to each of the openings 33a.

  As shown in FIG. 2, a cylindrical cylinder 35 as a whole is inserted through the through hole 32 a in the bottom wall 32 of the second housing 31. A flange portion 35 a is formed on the upper end portion of the cylindrical body 35. The flange portion 35 a of the cylindrical body 35 is fixed to the upper surface of the bottom wall portion 32 of the second housing 31 by a screw or the like (not shown). The cylindrical body 35 is also inserted through the through hole 15 a of the speed reduction mechanism 15 and the through hole 14 a of the upper wall portion 14 of the first housing 11 of the first arm C 3. Therefore, the cylindrical body 35 functions as a communicating portion that brings the hollow portion 11a of the first housing 11 of the first arm C3 into communication with the hollow portion 31a of the second housing 31 of the second arm C4.

  As shown in FIG. 2, a current collecting member 20 is provided on the bottom wall portion 12 of the first housing 11 in the first arm C3. The current collecting member 20 is electrically connected to the first power cable PC1. In the current collecting member 20, the lower end portion of the conductive member 50 having a columnar shape as a whole is accommodated. The conductive member 50 is electrically connected to the first power cable PC1 via the current collecting member 20. The conductive member 50 is inserted into the cylindrical body 35 so as to extend on the third rotation axis J3, and the upper end portion thereof extends to the hollow portion 31a of the second arm C4. The upper end portion of the conductive member 50 is fixed to a fixing member 40 provided on the upper wall portion 34 of the second housing 31 in the second arm C4. The second power cable PC2 is fixed to the fixing member 40. The second power cable PC2 and the conductive member 50 are electrically connected via the fixing member 40. As described above, in the present embodiment, the first power cable PC1 is electrically connected to the second power cable PC2 via the current collecting member 20, the conductive member 50, and the fixing member 40. Therefore, the conductive member 50 constitutes a part of a power cable for supplying power to the welding torch C9. In addition, in FIG. 2, in order to illustrate the connection relation of 1st power cable PC1, current collection member 20, electrically-conductive member 50, fixing member 40, and 2nd power cable PC2, these members are not described as sectional drawing. .

Next, more detailed configurations of the fixing member 40, the current collecting member 20, and the like will be described.
As shown in FIG. 2, the support plate 41 of the fixing member 40 has a square plate shape, and is extended from the top wall 34 of the second housing 31 of the second arm C4 toward the first arm C3. ing. The support plate 41 is fixed to the upper wall portion 34 of the second housing 31 with a screw or the like (not shown).

  As shown in FIG. 3, an insulating connecting member 42 is fixed to the surface on one side of the support plate 41 (the surface on the right side in FIG. 3). The connecting member 42 has a rectangular parallelepiped base 42 a and a projection 42 b protruding from the base 42 a at the center in the vertical direction (Y-axis direction in FIG. 3). The dimension in the thickness direction (the X-axis direction in FIG. 3) of the connecting member 42 is the same as the dimension in the lateral direction of the support plate 41. Screws 43 are inserted through the upper and lower portions of the base portion 42a along the projecting direction of the projecting portion 42b. The connecting member 42 is screwed and fixed to the support plate 41 by the screw 43. A through hole 42c (shown by a broken line in FIG. 3) penetrating in the thickness direction is formed in the projecting portion 42b of the connecting member 42.

  As shown in FIG. 3, at the other end of the second power cable PC2, a conductive crimp terminal 61 for fixing the second power cable PC2 to the connecting member 42 is attached. The crimp terminal 61 has a cylindrical portion 61 a covering the other end of the second power cable PC 2 and a flat plate portion 61 b extending from the cylindrical portion 61 a and having a flat plate shape. A through hole for inserting a bolt 65 is formed in the flat plate portion 61 b. The crimp terminal 61 is electrically connected to the internal wiring of the second power cable PC2.

  As shown in FIG. 3, the substantially cylindrical conductive member 50 is formed of a conductive portion 51 formed of a conductive material (for example, copper, aluminum, or an alloy thereof) in a columnar shape and the outer peripheral surface of the conductive portion 51. And an insulating coating 52 covering the A terminal portion 55 for fixing the conductive member 50 to the connecting member 42 is formed on the upper end surface of the conductive portion 51 so as to project therefrom. The terminal portion 55 is integrally formed with the conductive portion 51, and has a rectangular flat shape as a whole. A through hole for inserting a bolt 65 is formed at the tip of the terminal 55.

  As shown in FIG. 3, the conductive bolt 65 is inserted into the through hole of the flat plate portion 61 b of the crimp terminal 61, the washer 67, the through hole 42 c of the connecting member 42, and the through hole of the terminal portion 55 of the conductive member 50. There is. Further, a conductive nut 66 is screwed into the tip of the bolt 65. Therefore, the crimp terminal 61 attached to the other end of the second power cable PC2, the connecting member 42 of the fixing member 40, and the terminal 55 of the conductive member 50 are fixed to each other while being sandwiched by the bolt 65 and the nut 66. ing. The second power cable PC2 is electrically connected to the terminal 55 of the conductive member 50 via the crimp terminal 61, the bolt 65, and the nut 66. The fixing position of the fixing member 40 with respect to the upper wall portion 34 of the second housing 31 is determined so that the conductive member 50 is extended on the third rotation axis J3.

  As shown in FIG. 5, at the lower end portion of the conductive portion 51 of the conductive member 50, an exposed portion 51a not covered by the coating portion 52 is formed. The outer diameter of the exposed portion 51 a is formed larger than the outer diameter of the portion of the conductive portion 51 covered by the coating 52. Then, in the conductive member 50, the outer diameter of the portion where the film portion 52 is formed and the outer diameter of the exposed portion 51a are substantially the same. The conductive member 50 has a conductive sliding member 53 attached to the lower end surface of the exposed portion 51 a of the conductive portion 51. The sliding member 53 has a disk shape as a whole. The outer diameter of the sliding member 53 is the same as the outer diameter of the exposed portion 51 a of the conductive member 50. A recess 53 a is formed on the lower surface of the sliding member 53 (the lower surface in the vertical direction in FIG. 5). A screw hole is formed on the bottom surface (upper surface in FIG. 5) of the recess 53a, and the slide member 53 is fixed to the lower end surface of the exposed portion 51a by a screw 54 inserted through the screw hole. In addition, since the screw 54 is located inside the recess 53 a of the sliding member 53, the screw head of the screw 54 does not protrude below the lower end surface of the sliding member 53. A part of the lower end side of the conductive member 50 including the exposed portion 51 a and the sliding member 53 is accommodated in the current collecting member 20.

  As shown in FIG. 4, the support portion 21 of the current collecting member 20 is perpendicular to the fixing plate portion 21 a fixed to the bottom wall portion 12 of the first housing 11 in the first arm C 3 and the edge portion of the fixing plate portion 21 a And a standing plate portion 21b provided upright, and has a substantially L shape in a side view. As shown in FIGS. 4 and 5, a plurality of (two in the present embodiment) screws 22 are inserted in the fixing plate portion 21 a in the thickness direction, and the supporting portion 21 is the bottom of the first housing 11 by the screws 22. It is fixed to the wall 12.

  As shown in FIG. 4, a plurality of (only one is shown in FIG. 4) screws 23 are inserted in the thickness direction in the erected plate portion 21 b of the support portion 21, and the insulating accommodating portion 24 is inserted by the screws 23. It is fixed to the support portion 21. The housing portion 24 has a rectangular parallelepiped shape as a whole. In the housing portion 24, the fixing position of the support portion 21 with respect to the standing plate portion 21b is determined such that the lower end surface thereof and the fixing plate portion 21a of the support portion 21 are separated from each other.

  As shown in FIG. 5, the accommodation portion 24 of the current collection member 20 is formed with an accommodation hole 25 having a circular cross-section that penetrates from the upper end surface to the lower end surface. The central axis of the accommodation hole 25 is located on the third rotation axis J3. The accommodation hole 25 has a large diameter portion 25a, an intermediate diameter portion 25b whose inner diameter is smaller than that of the large diameter portion 25a, and a small diameter portion 25c whose inner diameter is smaller than that of the intermediate diameter portion 25b. The inner diameter of the large diameter portion 25 a of the housing hole 25 is formed to be the same as the outer diameter of the exposed portion 51 a of the conductive member 50 and the outer diameter of the sliding member 53. The large diameter portion 25 a of the accommodation hole 25 accommodates a part of the lower end side including the exposed portion 51 a of the conductive member 50 and the sliding member 53. The outer peripheral surface of the sliding member 53 of the conductive member 50 can rotate and move up and down while sliding against the inner peripheral surface of the large diameter portion 25 a of the housing portion 24. Therefore, "inside diameter and outside diameter are the same" in this embodiment is a concept that allows a slight difference in size to satisfy such a sliding relationship.

  As shown in FIG. 5, the housing hole 25 of the housing portion 24 houses a conductive current collector 26 electrically connected to the sliding member 53 of the conductive member 50. The current collector 26 has a cylindrical shaft 26 a and a disk 26 b connected to the upper end of the shaft 26 a. The outer diameter of the shaft portion 26 a is equal to the inner diameter of the small diameter portion 25 c of the accommodation hole 25. The shaft portion 26 a of the current collector 26 penetrates the small diameter portion 25 c of the housing hole 25, and a part of the lower end side of the shaft portion 26 a protrudes to the outside on the lower end surface side of the housing portion 24. In the current collector 26, the outer diameter of the disk portion 26 b is formed to be the same as the inner diameter of the large diameter portion 25 a of the accommodation hole 25. The upper surface of the disk portion 26 b is in contact with the lower surface of the sliding member 53 of the conductive member 50 so as to be able to slide and rotate. The current collector 26 is movable in the vertical direction while the outer peripheral surface thereof slides on the inner peripheral surface of the accommodation hole 25 of the accommodation portion 24.

  As shown in FIG. 5, the spring 27 as a biasing member is accommodated in the middle diameter portion 25 b of the accommodation hole 25 in the accommodation portion 24. The spring 27 is a so-called coil spring, and the shaft portion 26a of the current collector 26 is inserted at the center thereof. The lower end of the spring 27 is in contact with a step between the middle diameter portion 25 b and the small diameter portion 25 c in the housing hole 25. The upper end of the spring 27 is in contact with the lower surface of the disc portion 26 b of the current collector 26. Therefore, the spring 27 biases the current collector 26 to the upper side which is the conductive member 50 side.

  As shown in FIG. 5, a conductive mounting bracket 28 is attached to the lower end surface of the shaft portion 26 a in the current collector 26. The mounting bracket 28 is in the form of a long plate bent at a predetermined angle. One longitudinal end (right end in FIG. 5) of the mounting bracket 28 is fixed to the lower end face of the shaft 26 a of the current collector 26 by a screw 29. A through hole 28 a for inserting a bolt 75 is formed at the other end (left end in FIG. 5) of the mounting bracket 28 in the longitudinal direction.

  As shown in FIG. 5, a conductive crimp terminal 71 for fixing the first power cable PC1 to the mounting bracket 28 is attached to the other end of the first power cable PC1. The crimp terminal 71 has a cylindrical portion 71 a covering the other end of the first power cable PC 1 and a flat plate portion 71 b extending from the cylindrical portion 71 a and having a flat plate shape. A through hole 71c for inserting a bolt 75 is formed in the flat plate portion 71b. The crimp terminal 71 is electrically connected to the internal wiring of the first power cable PC1.

  As shown in FIG. 5, the conductive bolt 75 is inserted through the washer 77, the through hole 71 c of the flat plate portion 71 b of the crimp terminal 71, and the through hole 28 a of the mounting bracket 28. Further, a conductive nut 76 is screwed into the tip of the bolt 75. Therefore, the crimp terminal 71 and the mounting bracket 28 attached to the other end of the first power cable PC1 are fixed to each other while being sandwiched by the bolt 75 and the nut 76. The first power cable PC1 is electrically connected to the conductive member 50 via the crimp terminal 71, the bolt 75, the nut 76, the mounting bracket 28, and the current collector 26 of the current collector 20.

(Function of the embodiment)
The operation of the above embodiment will be described.
In the present embodiment, the conductive member 50 is fixed to the second housing 31 of the second arm C4 via the fixing member 40. Therefore, when the second arm C4 pivots relative to the first arm C3 about the third pivot axis J3, the conductive member 50 also pivots about the third pivot axis J3.

  Here, it is assumed that the lower end portion of the conductive member 50 is fixed to the first housing 11 of the first arm C3. In this case, the upper end portion of the conductive member 50 rotates with the second arm C4, while the lower end portion of the conductive member 50 is fixed to the first arm C3 and can not rotate. Therefore, the conductive member 50 is twisted. In this respect, in the present invention, although the lower end portion of the conductive member 50 is accommodated in the accommodation portion 24 of the current collecting member 20, it is not fixed. Therefore, the whole of the conductive member 50 rotates with the second arm C4, and the conductive member 50 hardly twists.

  On the other hand, when the second arm C4 rotates with respect to the first arm C3, the sliding member 53 of the conductive member 50 rotates while sliding on the disc portion 26b of the current collector 26 in the current collecting member 20. . That is, even if the second arm C4 rotates, the conductive member 50 and the current collector 26 of the current collection member 20 abut each other, and the electrical connection relationship between the two is maintained. Therefore, the power supply from the first power cable PC1 to the second power cable PC2 via the conductive member 50 is not interrupted as the second arm C4 rotates.

(Features of the embodiment)
The features of the above embodiments are described along with their effects.
(1) In the present embodiment, the sliding member 53 of the conductive member 50 can slide and rotate with respect to the disc portion 26 b of the current collector 26 of the current collecting member 20. Therefore, when the second arm C4 pivots relative to the first arm C3, the entire conductive member 50 pivots together with the second arm C4, and the pivoting power is hardly transmitted to the first power cable PC1. Therefore, the occurrence of twisting in the conductive member 50 can be reduced.

  (2) In the present embodiment, a part of the lower end side of the conductive member 50 is housed in the housing portion 24 of the current collecting member 20. Therefore, it can suppress that the position of the lower end part of the electrically-conductive member 50 shifts | deviates from the 3rd rotation axial center J3.

  (3) In the present embodiment, the current collector 26 in the current collector 20 is biased by the spring 27 toward the conductive member 50. Therefore, for example, even if the conductive member 50 moves up and down somewhat along the third rotation axis J3 as each arm of the robot R rotates, the movement of the current collecting member 20 follows that movement. The current collector 26 can also move up and down. Therefore, the certainty of maintaining the contact relation between the current collector 26 of the current collecting member 20 and the sliding member 53 of the conductive member 50 is improved.

  (4) In the present embodiment, the upper end portion of the conductive member 50 is fixed to the second housing 31 of the second arm C4 via the fixing member 40. Therefore, most of the weight of the conductive member 50 can be carried by the second housing 31 of the second arm C4, and excessive weight can be prevented from acting on the housing portion 24 and the current collector 26 in the current collecting member 20. .

  (5) In the present embodiment, the lower end surface of the sliding member 53 in the conductive member 50 abuts on the current collector 26 of the current collector 20. The direction of the force (for example, the biasing force of the spring 27) acting on the lower end face of the sliding member 53 from the current collector 26 of the current collecting member 20 is substantially along the third rotation axis J3. Accordingly, the conductive member 50 can be prevented from being inclined with respect to the third rotation axis J3 by the force from the current collector 26 of the current collection member 20.

  (6) In the present embodiment, the current collecting member 20 is provided to the first arm C3, and the current collecting member 20 is not provided to the second arm C4. As shown in FIG. 1, when the base C1 is installed on the ground, there is a high possibility that the first arm C3 is positioned lower than the second arm C4. As described above, by providing the current collecting member 20 on the arm that will be positioned on the lower side, this occurs as the current collector 26 of the current collecting member 20 and the sliding member 53 of the conductive member 50 slide. The wear powder can be retained in the housing portion 24 of the current collecting member 20.

  (7) In the present embodiment, the mounting bracket 28 is attached to the current collector 26 of the current collecting member 20, and the crimp terminal 71 attached to the other end of the first power cable PC1 is fixed to the mounting bracket 28. did. Therefore, compared with the case where the crimp terminal 71 is directly attached to the current collector 26, the attachment operation is easier to perform.

  (8) In the present embodiment, the first power cable PC1 and the second power cable PC2 are electrically connected to the conductive member 50, and the conductive member 50 is a power cable for supplying power to the welding torch C9. Act as part. And since a comparatively big electric current flows into this kind of power cable, a thick and highly rigid cable is used. Repeated twisting of a highly rigid cable is likely to cause breakage of the coating of the cable or breakage of the internal wiring of the cable. It is particularly preferable to adopt the configurations of the conductive member 50 and the current collecting member 20 of the above-described embodiment as the configuration relating to such a power cable.

(Modification example)
The above embodiment may be modified as follows. In addition, each modification may be combined appropriately and applied.

  In the above embodiment, the conductive member 50 and the current collecting member 20 are applied to the joint structure of the first arm C3 and the second arm C4, but the conductive member 50 and the current collecting member 20 are applied to other joint structures. May be For example, the joint structure of the base C1 and the swivel base C2, the joint structure of the swivel base C2 and the first arm C3, the joint structure between other arms, and the joint structure of the fifth arm C7 and the tool fixing member C8 The member 50 and the current collecting member 20 may be applied.

  The robot to which the present invention is applied is not limited to the articulated robot R of the above embodiment as long as it has at least one joint structure. For example, the robot may be a transport robot that grips and transports an article, or an inspection robot that images and inspects a predetermined portion of a work.

  In the above embodiment, the first power cable PC1 and the second power cable PC2 are electrically connected to the conductive member 50, but instead of the power cables, the control cable is electrically connected to the conductive member 50. You may do so. In this case, the conductive member 50 functions as a part of a control cable. In addition, as a cable for control, the cable etc. for exchanging a signal with the motor used as the drive source of rotation of each arm are mentioned, for example.

  In the above embodiment, the current collecting member 20 is provided on the side of the first arm C3 which is the fixed side member so that the conductive member 50 and the current collecting member 20 abut against each other so as to slide and rotate. Not limited to such a configuration, the current collecting member 20 may be provided on the side of the second arm C4, which is a pivoting member, so that the conductive member 50 and the current collecting member 20 abut against sliding rotation. In this case, the current collecting member 20 may or may not be provided on the first arm C3 which is the fixed side member. That is, the conductive member 50 and the current collecting member 20 may be in sliding contact with each other in at least one of the fixed side member and the rotating member.

  -A configuration (a screw hole) for fixing the fixing member 40 is provided in the first housing 11 of the first arm C3 so that the fixing member 40 can be attached instead of the current collecting member 20 as needed. May be Similarly, a configuration (a screw hole) for fixing the current collecting member 20 in the second housing 31 of the second arm C4 may be provided, and the current collecting member 20 may be attached instead of the fixing member 40 as necessary. It may be possible. According to this modification, for example, the current collecting member 20 can be provided to either of the first arm C3 and the second arm C4 according to the posture or the like in which the robot R is installed.

  In the embodiment, the current collector 26 of the current collector 20 may abut on the outer peripheral surface of the sliding member 53 in the conductive member 50. That is, when the conductive member 50 rotates about the third rotation axis J3, if the contact relationship between the sliding member 53 of the conductive member 50 and the current collector 26 of the current collection member 20 can be maintained. It may be in any form.

  In the embodiment, the sliding member 53 in the conductive member 50 may be omitted, and the exposed portion 51 a of the conductive member 50 may be in direct contact with the current collector 26 of the current collector 20. In this case, for example, it is preferable to reduce the frictional force of the current collecting member 20 to the current collector 26 by processing the lower surface of the exposed portion 51a of the conductive member 50 smoothly, for example, mirror finish.

  -The structure of the spring 27 in the current collection member 20 is not restricted to the thing of the said embodiment. For example, a leaf spring is interposed between the fixing plate portion 21a of the support portion 21 of the current collecting member 20 shown in FIG. 5 and the mounting bracket 28, and the current collector 26 is urged toward the conductive member 50 together with the mounting bracket 28. You may do so.

  The spring 27 in the current collecting member 20 can be omitted. For example, in the conductive member 50, when a sliding brush made of a plurality of conductive wires is employed instead of the sliding member 53, the sliding brush can be elastically deformed to some extent. Therefore, the contact relationship between the sliding brush of the conductive member 50 and the current collector 26 of the current collector 20 can be maintained even if the current collector 26 of the current collector 20 is not biased by the spring 27.

  In the conductive member 50, the sliding member 53 may be biased toward the current collector 26 side of the current collecting member 20. Specifically, for example, in the conductive member 50, a spring member may be interposed between the conductive portion 51 and the sliding member 53. Even in this case, a good contact relationship between the sliding member 53 of the conductive member 50 and the current collector 26 of the current collector 20 can be maintained.

  In the current collecting member 20, the housing portion 24 of the current collecting member 20 is formed of a conductive material, and the sliding member 53 of the conductive member 50 is in sliding contact with the housing portion 24 of the current collecting member 20. May be In this case, if the first power cable PC1 is electrically connected to the housing portion 24, the current collector 26 can be omitted, and the housing portion 24 itself also functions as a current collector.

In the current collecting member 20, the housing portion 24 of the current collecting member 20 can be omitted. In this case, the current collector 26 is fixed to the standing plate portion 21 b of the support portion 21.
The metal fitting 28 of the current collecting member 20 may be omitted, and the crimp terminal 71 attached to the other end of the first power cable PC1 may be attached directly to the current collector 26. Further, another metal fitting may be interposed between the mounting metal fitting 28 and the crimp terminal 71 in the current collecting member 20. That is, as long as the first power cable PC1 is electrically connected to the current collector 26 of the current collection member 20, the configuration is not limited.

  In the above embodiment, the second power cable PC2 is inserted into the cylindrical body 35, and the other end of the second power cable PC2 is slidably brought into contact with the current collector 26 of the current collecting member 20. You may In the case of this modification, the configuration of the sliding member 53 or the like of the above embodiment may be employed at the other end of the second power cable PC2. In the case of this modification, the second power cable PC2 corresponds to the conductive member communicated with the cylindrical body 35 (communication portion).

  The configuration of the upper end portion of the conductive member 50 can be appropriately changed as long as the conductive member 50 can be fixed to the fixing member 40 in the conductive member 50. For example, instead of integrally forming the terminal portion 55 on the upper end surface of the conductive portion 51 in the conductive member 50, a terminal member separate from the conductive portion 51 may be fixed to the upper end portion of the conductive portion 51. Good.

  In the embodiment, the configuration of the fixing member 40 does not matter. The upper end portion of the conductive member 50 can be fixed to the second housing 31 of the second arm C4, and the second power cable PC2 and the conductive member 50 can be electrically connected, regardless of the configuration. It can be adopted as the fixing member 40.

The technical idea based on the above-mentioned embodiment and modification is added below.
The robot is an arc welding robot having a welding torch, and a power cable for supplying power to the welding torch is electrically connected to the conductive member.

  -A conductive mounting bracket is fixed to the current collector, and a conductive cable is electrically connected to the mounting bracket.

  R: Robot, C1: base, C2: swivel base, C3: first arm, C4: second arm, C5: third arm, C6: fourth arm, C7: fifth arm, C8: tool fixing member, PC1 ... 1st power cable, PC 2 ... 2nd power cable, J3 ... 3rd rotation axis, 11 ... 1st housing, 20 ... current collection member, 24 ... housing part, 25 ... housing hole, 26 ... current collector, Reference Signs List 27 spring 28 mounting bracket 31 second housing 35 cylindrical body 40 fixing member 50 conductive member 53 sliding member

Claims (2)

A joint structure of a robot including a stationary side member and a pivoting member rotatable with respect to the stationary side member,
A communication portion is provided on the rotation axis of the rotation member, for communicating the inside of the fixed side member with the inside of the rotation member.
A conductive member is inserted into the communication portion,
A current collecting member electrically connected to the conductive member is provided on at least one of the fixed side member and the rotating member,
A cable member is attached to the current collecting member so as to be electrically connected to the conductive member,
The current collecting member is
An insulating accommodating portion for accommodating the end of the conductive member;
A conductive current collector which is slidably brought into contact with the end of the conductive member so as to be rotatably connected and electrically connected to the end of the conductive member;
A joint structure of a robot, comprising: a biasing member biasing the current collector toward the conductive member . The current collecting member to which one end of the conductive member is electrically connected is provided on any one of the fixed side member and the rotating member.
A fixed member to which the other end of the conductive member is fixed is provided on either the fixed side member or the other of the rotating members,
The joint structure of a robot according to claim 1 , wherein a tip end surface at one end of the conductive member is in sliding contact with the current collecting member so as to be slidable.