JP2003285166A - Slide contact and robot with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slide contact which can stably energize even in an environment in which a dust or sputter is generated and which has excellent maintainability and to provide a robot with the slide contact. <P>SOLUTION: Since this slid contact has a cleaning groove 34 disposed at an annular electrode 30 side, even if the dust or the sputter adhered to the electrode 30 is sandwiched between the electrode 30 and a block electrode 40, when the electrode 40 passes across the groove 34, the dust or the sputter is scraped and removed by the groove 34. Thus, the dust or the sputter is prevented from being stacked between the electrode 40 and the electrode 30, and hence a stable energization can be performed. Further, since the groove 34 is constituted in a gap between arcuate electrodes 33 and 33, a cost can be reduced as compared with the case in which a cleaning groove is formed separately from the above-mentioned gap. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows electrodes fixed to a pair of members to slide with each other as the members rotate relative to each other, thereby electrically connecting electric paths connected to the electrodes. The present invention relates to a sliding contact and a robot with a sliding contact equipped with such a sliding contact in a rotary joint.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 3019068 discloses a welding system having a positioner 1 in front of a welding robot R1 as shown in FIG.
This positioner 1 includes a base portion 2 as shown in FIG.
Is equipped with a turntable 3 on the upper surface of the
A motor 5 provided with a rotating shaft 4 that hangs inside the base portion 2
Is rotated to change the posture of the work fixed on the turntable 3. The conventional sliding contact is provided inside the positioner 1 and slidably joins the annular electrode 6 attached to the rotary shaft 4 and the carbon electrode 7 attached to the bottom wall 2A of the base portion 2. The welding power source 9 connected to the carbon electrode 7 and the work connected to the annular electrode 6 are electrically connected to each other. Further, the sliding surface of the carbon electrode 7 is provided with a groove 8 for eliminating abrasion powder of the carbon electrode 7 itself.

[0003]

By the way, the groove 8 provided in the conventional sliding contact is for removing the abrasion powder of the carbon electrode 7 itself and is provided in the carbon electrode 7 itself. The following problems occur. That is, when the carbon electrode 7 is pressed against a part of the ring-shaped electrode 6 and slides, dust attached to the ring-shaped electrode 6 accumulates at the end of the carbon electrode 7. The carbon electrode 7 is attached to the dust.
However, if the carbon electrode 7 is slid once, dust is not easily removed, and dust may eventually accumulate between the electrodes 6 and 7 to cause conduction failure. Therefore, dust
When using a sliding contact in a space where spatter etc. can occur, it is necessary to develop a sliding contact that can easily remove dust, spatter, etc. adhering to the annular electrode. Further, in the conventional sliding contact, the annular electrode 6 cannot be removed from the rotating shaft 4 unless the positioner 1 is disassembled, so that maintenance work is very difficult.

The present invention has been made in view of the above circumstances and provides a sliding contact and a robot with a sliding contact which are capable of achieving stable conduction even in an environment where dust or spatter is generated and which are excellent in maintainability. For the purpose of provision.

[0005]

The sliding contact according to the invention of claim 1 made in order to achieve the above object, surrounds the outer side of one of a pair of rotatably connected members. An annular electrode fixed to any member and a block electrode fixed to a member on the opposite side of the annular electrode and pressed against a part of the annular electrode are provided. At the sliding contact where the ring electrode and the block electrode slide along with the rotation and the electric paths connected to the ring electrode and the block electrode are electrically connected, the ring electrode is cleaned across the slide path of the block electrode. The feature is that the groove is formed.

According to a second aspect of the present invention, there is provided a sliding contact, which includes an annular electrode which surrounds an outer side of one of a pair of members rotatably connected to each other and is fixed to any one of the members. The block electrode is fixed to a member on the opposite side and is pressed against a part of the annular electrode, and the annular electrode and the block electrode slide with relative rotation between the pair of members, In the sliding contact for conducting between the electric paths respectively connected to the annular electrode and the block electrode, the annular electrode is
A characteristic is that a plurality of arc-shaped electrodes are united in the circumferential direction, and a cleaning groove that crosses the sliding path of the fixed block in the annular electrode is formed by the gap provided between the arc-shaped electrodes.

The invention according to claim 3 is characterized in that, in the sliding contact according to claim 2, the annular electrode is configured so as to form a circular shape as a whole by combining a plurality of arc-shaped electrodes and the cleaning groove. .

According to a fourth aspect of the present invention, in the sliding contact according to the second or third aspect, both ends of each of the adjoining arc-shaped electrodes are fixed to connect the arc-shaped electrodes to each other so that they are flush with each other. Is arranged on the side of the sliding path of the block electrode in the annular electrode.

According to a fifth aspect of the present invention, in the sliding contact according to any one of the first to fourth aspects, the block electrode is fixed to the member via a coil spring, and the block electrode is provided around the block electrode. It is characterized in that a space is provided to allow tilting of the.

According to a sixth aspect of the present invention, in the sliding contact according to any of the first to fifth aspects, an annular cover is installed to cover the sliding path of the block electrode in the annular electrode, and the annular cover is used as the block electrode. It is characterized by being locked.

According to a seventh aspect of the invention, in the sliding contact according to the sixth aspect, the annular cover is formed by cutting a part of an annular resin plate, and the cut portion is expanded by deformation of the resin plate to form the annular cover. The feature is that the member can be received inside.

According to another aspect of the present invention, there is provided a robot with sliding contacts, wherein a robot provided with a plurality of links connected by rotary joints is provided with an electric path, and electric paths on both sides of the rotary joint are electrically connected by sliding contacts. In the robot with sliding contact, the sliding contact has an annular electrode that surrounds one of the links connected by the rotary joint and is fixed to any one of the links, The block electrode is fixed to the link and is pressed against a part of the annular electrode, and the annular electrode is formed by combining a plurality of arc-shaped electrodes. It is characterized in that a cleaning groove is formed across the sliding path of the fixed block.

[0013]

<Invention of claim 1><Invention of claim 1> In the sliding contact of claim 1, since the cleaning groove is arranged on the annular electrode side, dust or spatter adhering to the annular electrode is formed between the block electrode and the block electrode. Even if they are pinched, when the block electrode passes across the cleaning groove, the dust and spatter are scraped off by the cleaning groove and eliminated. This prevents dust and spatter from accumulating between the block electrode and the ring-shaped electrode, so that stable energization can be achieved. It should be noted that the pair of members in the present invention may be a pair of links connected by a rotary joint in the robot.

<Invention of Claim 2> According to the sliding contact of Claim 2, a plurality of arc-shaped electrodes are combined from the side of a pair of rotatably connected members to form an annular electrode. By doing so, the annular electrode can be attached to and detached from the member without disassembling each member. This improves the maintainability as compared with the conventional one. Further, since the cleaning groove is arranged on the ring electrode side, even if dust or spatter attached to the ring electrode is sandwiched between the block electrode and the ring electrode, when the block electrode passes across the cleaning groove, the dust or spatter Spatter is scraped off by the cleaning groove and eliminated. This prevents dust and spatter from accumulating between the block electrode and the ring-shaped electrode, so that stable energization can be achieved. Moreover, since the cleaning groove is formed by the gap between the arc-shaped electrodes, the cost can be reduced as compared with the case where the cleaning groove is provided separately from the gap.

<Invention of Claim 3> In the sliding contact according to claim 3, the annular electrode is circular as a whole including the plurality of arc-shaped electrodes and the cleaning groove. Therefore, in manufacturing the annular electrode, a circular member is used. Can be cut, and the cutting allowance can also be used as the cleaning groove, which simplifies the design and processing.

<Invention of Claim 4> According to the sliding contact of Claim 4, the two arc-shaped electrodes connected by the connecting plate with the cleaning groove interposed therebetween have a surface closer to the connecting plate. It becomes more accurate and flush than the opposite side. Then, since the block electrode slides on the more accurately flushed surface, the block electrode can smoothly pass through the cleaning groove.

<Invention of Claim 5> According to the sliding contact of Claim 5, even if the angle of the annular electrode with respect to the rotation axis of the member varies, the block electrode pressed against the annular electrode is the annular electrode. The block electrode and the annular electrode can be brought into close contact with each other by tilting in accordance with the angle.

<Invention of Claim 6> According to the configuration of Claim 6, the sliding path of the block electrode in the annular electrode is covered with the annular cover, and dust and spatter are prevented from adhering to the sliding path. You can Also, the annular cover is
Since it is locked to the block electrode and relatively moves on the ring electrode together with the block electrode, it does not interfere with the conduction between the ring electrode and the block electrode.

<Invention of Claim 7> According to the configuration of Claim 7, the annular cover is formed by cutting a part of an annular resin plate, and the cut portion is expanded by deformation of the resin plate to form the annular cover. Since the members can be received inside, the annular covers can be easily attached and detached from the side of the pair of members.

<Invention of claim 8> According to the robot with sliding contacts of claim 8, a plurality of arc-shaped electrodes are addressed to one another from the side of the link connected by the rotary joint to form an annular electrode. Thus, the annular electrode can be attached to and detached from each link without disassembling each link. This improves maintainability. Further, since the cleaning groove is arranged on the ring electrode side, even if dust or spatter attached to the ring electrode is sandwiched between the block electrode and the ring electrode, when the block electrode passes across the cleaning groove, the dust or spatter Spatter is scraped off by the cleaning groove and eliminated. This prevents dust and spatter from accumulating between the block electrode and the ring-shaped electrode, so that stable energization can be achieved. Moreover,
Since the cleaning groove is composed of the gap between the arc electrodes,
The cost can be reduced as compared with the case where the cleaning groove is provided separately from the gap.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> A first embodiment of the present invention will be described below with reference to FIGS. Figure 1
Shows a welding system that performs arc welding by cooperatively controlling the welding robot R1 and the workpiece holding robot R2. The welding robot R1 is fixed to the upper end of the front surface 10F of the support column 10 and has a welding torch 11 at the tip. A welding power cable (not shown) extending from the welding torch 11 is routed above the welding robot R1 and connected to a positive electrode of a welding power source (not shown).

On the other hand, the work holding robot R2 corresponds to the "robot with sliding contacts" of the present invention, and is fixed to an intermediate portion of the front surface 10F of the support column 10 in the vertical direction, and a jig for fixing the work at the tip. 13 is provided. Then, sliding contacts according to the present invention are provided to the rotary joints 21, 22, and 23 of the work holding robot R2 (not shown in FIG. 1, see FIG. 2).
Is provided, and the jig 13 is connected to the negative electrode of the welding power source by the electric path conducted by the sliding contacts.

As shown in FIG. 2, the first rotary joint 21 of the work holding robot R2 (hereinafter, simply referred to as “robot R2” as appropriate) has a base portion 24 fixed to the column 10.
And a base end portion of the first arm 25 are rotatably connected to each other, and the second rotary joint 22 rotatably connects a tip end portion of the first arm 25 and a base end portion of the second arm 26. Therefore, the third rotary joint 23 is formed by rotatably connecting the tip end portion of the second arm 26 and the flange 27. In this embodiment, the base portion 24 and the first and second arms 25, 2 are
6. The flange 27 corresponds to the "member" and the "link" according to the present invention.

In FIG. 2, the rotation angles of the first to third rotary joints 21, 22 and 23 (hereinafter simply referred to as "first to third joints 21, 22 and 23") are 0 °. The so-called origin posture of the robot R2 is shown.

The first arm 25 has, for example, a distance of 4 between both ends.
The structure is bent at an angle of 5 °. And FIG.
As shown in, the rotation axis J1 of the first joint 21 at the base end portion of the first arm 25 is oriented in the horizontal direction orthogonal to the front surface 10F of the support column 10, and the rotation axis J1 of the first arm 25 with respect to the rotation axis J1. The rotation axis J2 of the second joint 22 at the tip is 4
They intersect at an angle of 5 °.

The second arm 26 also has, for example, 45 between both ends.
The structure is bent at an angle of °. Then, in the origin posture of the robot R2, the rotation axis J of the third joint 23
3 coincides with the rotation axis J1 of the first joint 21, and these three rotation axes J1, J2, J3 always intersect at the same point (point P1 in FIG. 2) regardless of the posture of the robot R2.

As shown in FIG. 2, the sliding contacts provided on each of the joints 21, 22, and 23 both have an annular electrode 30 and a block electrode 40, and have the same basic structure. First, the third joint 23 will be described in detail.

The third joint 23 is shown enlarged in FIGS. As shown in the figure, a columnar portion 26A projects from the tip of the second arm 26.
The turntable 28 is directly connected to the output shaft of a speed reducer unit (not shown) built in the 6A, and the flange 2 is attached to the turntable 28.
7 is fixed. Then, the speed reducer unit is driven by a motor (not shown), and the flange 27 rotates together with the turntable 28 with respect to the second arm 26. The annular electrode 30 is fixed to the flange 27.

As shown in FIG. 5, the annular electrode 30 has a pair of arc-shaped electrodes 33, 33, both ends of which are connected by a connecting plate 35, and has a circular shape as a whole (see FIG. 5). Then, the ring-shaped electrode 30 has the cylindrical portion 2 as shown in FIG.
6A and the outer side of the turntable 28 are loosely fitted. here,
Explaining the manufacturing method of the arc-shaped electrodes 33, 33, first,
As shown in FIG. 6 (A), for example, a plurality of insertion holes 33 are formed in an annular disc 33A whose outer peripheral surface and inner peripheral surface are concentric.
B and the screw hole 33C are processed in advance. And FIG.
As shown in (B), a pair of arc-shaped electrodes 33, 33 is formed by cutting the disc 33A at two positions 180 ° apart.
Is manufactured. Therefore, if both ends of the arc-shaped electrodes 33, 33 are butted against each other with a gap equal to the width T of the cutting margin, the whole becomes substantially the same circular shape as the disc 33A.

The assembling of the arc electrodes 33, 33 is as follows. That is, as shown in FIG. 7, both arc-shaped electrodes 33, 33 are addressed from both sides of the columnar portion 26A and the turntable 28, and both end portions of both arc-shaped electrodes 33, 33 are cut off as shown in FIG. Butt with the same gap as the width T. Then, the ends of the arc-shaped electrodes 33, 33 are
The annular electrodes 30 are connected by the connecting plates 35, 35.
In addition, the gap between the arc-shaped electrodes 33, 33 constitutes the cleaning groove 34 according to the present invention. That is, in the present embodiment, the cutting allowance when the arc-shaped electrodes 33, 33 are manufactured is also used as the cleaning groove 34, whereby the entire annular electrode 30 including the arc-shaped electrodes 33, 33 and the cleaning grooves 34, 34 is combined. Since the circular shape is the same as the circular plate 33A, simplification of design and processing can be achieved. The width of the cleaning width 34 is the width T of the cutting allowance.
The width is not limited to the above, as long as it can store spatter and the like and can maintain contact with the block electrode.

The connection plates 35, 35 will be described in detail below. The connecting plate 35 is formed by penetrating a pair of screw holes 35N, 35N at both ends of the flat plate as shown in FIG. 7, and as shown in FIG. 8, on the inner edge side of the annular electrode 30 of the arc-shaped electrodes 33, 33. As shown in FIG. 3, a bolt that penetrates the annular electrode 30 from the side opposite to the connecting plate 35 is screwed into the screw hole 35N so that both ends of the connecting plate 35 are connected to the arc-shaped electrodes 33. It is fixed. This allows
On one surface of the ring-shaped electrode 30, the arc-shaped electrodes 33, 33 are pressed against the end surface of the connecting plate 35 to be flush with each other.

As shown in FIG. 3, in the annular electrode 30, the arc electrodes 33, 33 are flush with each other (that is, the connecting plate 3).
The surface on which 5 is laid) is directed to the second arm 26 side and is fixed to the flange 27 via a plurality of brackets 32 (only one bracket 32 is shown in FIG. 3, see FIG. 5). . Further, the annular electrode 30 is electrically connected to the jig 13 via the cable 50 as shown in FIG. The annular electrode 30 is also electrically connected to the flange 27 via the bracket 32.

On the other hand, the block electrode 40 is provided as a part of the electrode unit 41 as shown in FIG. The electrode unit 41 is provided with the block electrode 40 housed in a recess 43 formed in the insulating resin case 47. Specifically, as shown in FIG. 9, by fixing the end portions of the pair of coil springs 44, 44 extending from the rear end surface of the block electrode 40 to the inner wall of the recess 43, the block electrode 40 becomes an insulating resin case. It is floating from the inner wall of 47, and always
The rear end of the block electrode 40 is housed in the recess 43 and the front end projects from the opening of the recess 43. Further, a projecting piece 46 projects laterally from the rear end edge of the electrode unit 41, and the projecting piece 46 and the regulation wall 45 projecting inward from the opening edge of the recess 43 allow the block electrode 40. Is restricted from leaving the recess 43. Further, one end of a cable 51 is connected to the rear end surface of the block electrode 40, and the cable 51 is inserted into a through hole 47C provided in the inner wall of the recess 43 and extends rearward of the insulating resin case 47. ing. The cable 51 is covered with an insulating coating except for the terminal portion.

The electrode unit 41 constructed as described above
Are arranged at two positions with an interval of 180 ° in the annular electrode 30 as shown in FIG.
Insulating resin case 47 of 41 is bracket 4
It is fixed to the second arm 26 via 2, 42. As a result, the block electrode 40 is insulated from the second arm 26.

Further, as shown in FIG.
0 is arranged outside the connecting plate 35 in the radial direction of the annular electrode 30. Therefore, the block electrode 40 does not interfere with the connecting plate 35 even if the annular electrode 30 rotates.

Further, the block electrode 40 is the annular electrode 3
The coil spring 44 is pressed against 0 and is compressed and deformed. Here, since the block electrode 40 floats from the inner wall of the insulating resin case 47, one end surface of the block electrode 40 is pressed against the annular electrode 30,
The block electrode 40 is tilted according to the annular electrode 30. Thereby, even if the angle of the annular electrode 30 with respect to the rotation axis of the flange 27 varies, the block electrode 40 and the annular electrode 30 are in close contact with each other.

Moreover, in the present embodiment, the connecting plate 35 of the annular electrode 30 is laid and the block electrode 40 is joined to the surface where the arc-shaped electrodes 33, 33 are flush with each other. When the block electrode 40 slides on the annular electrode 30 and passes through the cleaning groove 34 as the joint rotates, the block electrode 40 can smoothly pass through the cleaning groove 34 (that is, between the arc-shaped electrodes 33, 33).

As shown in FIG. 3, one electrode unit 4
A terminal block 52 is fixed to the second arm 26 in the vicinity of 1. As shown in FIG. 10, this terminal block 52 is composed of an elongated metal block and has a pair of through holes 53, 5 at one end.
3 is provided. Insulating washers 54 are laid on both openings of the through holes 53, 53. Further, counterbore holes 54Z are formed at the opening edges of the through holes 53, 53 on the upper surface side of the terminal block 52, and one insulating washer 54 is fitted in the counterbore holes 54Z and is centered with respect to the through holes 53. ing. Then, the bolt passed through the insulating washer 54 is centered in the center of the through hole 53, and is screwed to the second arm 26 in a state of not contacting the terminal block 52. Further, an insulating washer 55 for raising is laid under the insulating washer 54 on the lower surface side of the through hole 53 so that the entire terminal block 52 is floated from the second arm 26. As a result, the terminal block 52 is fixed while being insulated from the second arm 26.

Then, as shown in FIG. 2, the terminals 51T and 51T at the tips of the cables 51 and 51 extending from both the block electrodes 40 and 40 are overlapped and fastened together to the terminal block 52. As a result, both block electrodes 40, 40 are electrically connected.

The terminal block 52 has the cable 51
Terminal 5 at one end of thicker relay cable 56 (see FIG. 2)
6T is bolted, the other terminal of this relay cable 56 is fixed to the annular electrode 30 provided in the second joint 22, and the electric path according to the present invention in the second arm 26 is configured.

The sliding contact of the third joint 23 is as described above. Next, the sliding contact of the second joint 22 is described above.
Only the structure different from the sliding contact of the joint 23 will be described. The same components as those of the sliding contact of the third joint 23 are designated by the same reference numerals and duplicate description will be omitted.

FIG. 11 shows the second joint 22 on an enlarged scale. As shown in the figure, the annular electrode 30 of the second joint 22 is fixed to the base end portion of the second arm 26. Here, the annular electrode 30 in the third joint 23
Was electrically connected to the flange 27 via the bracket 32, but in the second joint 22, the annular electrode 30 is connected to the second arm 2.
The bracket 32C fixed to 6 insulates the annular electrode 30 and the second arm 26 from each other. For details, see FIG.
In the figure, one of the brackets 32C to which the annular electrode 30 of the second joint 22 is fixed is shown in an enlarged manner. The bracket 32C is composed of a metal block, and has a pair of through holes 6
Equipped with 0,60. Insulating washers 61, 61 are laid on both openings of the through holes 60, 60. Then, the bolt-side insulating washer 61 is centered with respect to the through hole 60 by the counterbore hole 61Z formed at the opening edge of the through hole 60. As a result, the insulating washer 6
The bolt passed through 1 is centered in the center of the through hole 60,
The bracket 32C is held so as not to come into contact with it.
Further, the insulating washer 61 provided on the side of the through hole 60 allows the entire bracket 32C to float from the second arm 26. Thereby, the bracket 32C
Are fixed while being insulated from the second arm 26. Similarly, the other bracket 32C is also subjected to the insulation process using the insulation washer 61. Thereby, the annular electrode 30 of the second joint 22 is fixed to the second arm 26 in an insulated state.

Further, in the second joint 22, as shown in FIG. 2, the block electrode 4 fixed to the first arm 25 is used.
Thick relay cable 5 together with 0 and 40 cables 51
The terminal 57T at one end of 7 is fixed to the terminal block 52,
The terminal 57T at the other end of the relay cable 57 is fixed to the annular electrode 30 of the first joint 21 (see FIG. 13).

The sliding contact of the second joint 22 has been described above. Below, only the structure of the sliding contact of the first joint 21 different from the sliding contacts of the second and third joints 22 and 23 will be described. . The same components as those of the sliding contacts of the second and third joints 22 and 23 are designated by the same reference numerals and duplicate description will be omitted.

FIG. 13 is an enlarged view of the base end portion of the first arm 25 connected by the first joint 21, and the slide of the first joint 21 on the base end portion of the first arm 25 is shown. The annular electrode 30 provided at the contact is fixed. Here, the annular electrode 30 in the second joint 22 is
In the same manner as in the above case, it is fixed to the base end portion of the first arm 25 in an insulated state.

In the first joint 21, as shown in FIGS. 2 and 14, one end of the cable 58 extending from the negative electrode of the welding power source together with the cable 51 of the block electrodes 40, 40 fixed to the base portion 24. The terminal of is connected. As described above, the cables 50, 51, 56, 57, 58 as electric circuits provided on the work holding robot R2.
However, the joints are connected by sliding contacts provided on the joints 21, 22, and 23 so that the negative electrode of the welding power source and the jig 13 are electrically connected.

Next, the operation of the welding system of the present embodiment having the above configuration will be described. Before performing welding, the welding robot R1 and the work holding robot R2 are set in a predetermined standby posture, the work holding robot R2 holds a work (not shown), and the welding power source is turned on. At this time, the negative electrode of the welding power source and the jig 13 are electrically connected, but the welding torch 11 connected to the positive electrode of the welding power source and the work are isolated from each other, so that the welding power source and the jig 13 are separated from each other. No current flows between them.

When the welding system is activated, the robots R1 and R2 move their joints to change their postures. here,
Workpiece holding robot R2 regardless of posture
In each joint 21, 22, 23 of the block electrode 4
0 slides on the annular electrode 30 to maintain the conductive state. When the robots R1 and R2 are in a predetermined posture and the tip of the welding torch 11 (specifically, the tip of the welding wire derived from the welding torch 11) approaches the work, the tip of the welding torch 11 and the work An arc is generated between the cables and the electric path connecting the positive and negative electrodes of the welding power source is closed, and the cables 50, 51, 56, 57, 58 fixed to the work holding robot R2 forming a part of the electric path, A current flows through the sliding contact (block electrode 40, annular electrode 30).

In order to secure the quality of the welded part, the torch 1
1 is always held with its tip facing downward. Therefore, the posture change when welding the side surface of the work is exclusively performed by the work holding robot R2, and each rotary joint of the work holding robot R2 requires more complicated and larger movement than each rotary joint of the welding robot R1. To be done. Therefore, unlike the welding robot R1, the work holding robot R2 cannot secure an electric path by arranging the cables.

Here, the third part of the work holding robot R2 is
In the joint 23, the annular electrode 30 of the sliding contact is electrically connected to the flange 27 as shown in FIG.
The robot R is provided at a portion other than the conductive portion between the ring 7 and the annular electrode 30.
Since there is no electric path that connects 2 and the welding power source, the robot R
2 The main body is not leaked, and the cables 50, 51, 5
A current flows from the jig 13 to the welding power source through 6, 57, 58 and the sliding contacts.

It is conceivable that when welding is started, spatter is generated and reaches each sliding contact, and the spatter adheres to the annular electrode 30. Then, when the work holding robot R2 rotates, spatter is accumulated at the end of the annular electrode 30, and in some cases, the sputter is sandwiched between the annular electrode 30 and the block electrode 40.

However, each time the block electrode 40 passes through the cleaning groove 34 of the ring-shaped electrode 30 due to the change in the posture of the robot R2, the spatter accumulated at the end of the ring-shaped electrode 30, the block electrode 40, and the ring-shaped electrode 30. The spatter sandwiched between the two is scraped off by the cleaning groove 34. This prevents spatter from accumulating between the block electrode 40 and the annular electrode 30. Moreover, the cleaning groove 34
Since it is configured with a gap between the arc-shaped electrodes 33, 33,
The cost can be reduced as compared with the case where the cleaning groove is formed separately from the gap. Further, since the cleaning groove 34 penetrates the annular electrode 30 in the thickness direction, it is unlikely that the cleaning groove 34 is filled with the scraped spatter or dust. Further, the block electrodes 40 are provided in pairs on each sliding contact and are pressed against the two locations of the annular electrode 30, so that the energization state of one of the block electrodes 40 temporarily decreases. Also, stable energization can be achieved by the other block electrode 40 and the annular electrode 30.

When welding is completed, each robot R1, R2
Is returned to the standby position, replaced with a new work, and the work is welded again in the same manner as above. The robot R2
If the programming is performed so that the block electrode 40 surely passes through the cleaning groove 34 when returned to the standby position one by one, it is possible to more reliably eliminate the spatter between the annular electrode 30 and the block electrode 40. it can.

By the way, for maintenance of the robot R2, for example, the sliding contact may be required to be replaced. In this case, the connecting plate 35 may be removed from the annular electrode 30 and disassembled into the two arc-shaped electrodes 33, 33. Thereby, the annular electrode 30 can be detached to the side of the robot R2 without disassembling the robot R2. Further, in order to attach the new annular electrode 30 to the robot R2, a pair of arc-shaped electrodes 33,
33 may be united by the connecting plate 35. Further, the block electrode 40 and other parts related to the electric path can be easily replaced by engaging and disengaging the bolts.

As described above, according to the sliding contact and the robot with sliding contact (robot R2) of this embodiment, accumulation of dust and spatter between the block electrode 40 and the annular electrode 30 can be prevented. In addition, stable energization can be achieved and maintenance can be easily performed. Moreover, since the cleaning groove 34 is formed by the gap between the arc-shaped electrodes 33, 33, the cost can be reduced as compared with the case where the cleaning groove is formed separately from the gap.

<Second Embodiment> This embodiment will be described with reference to FIGS.
The robot R of the first embodiment shown in FIG.
An annular cover 70 is additionally provided on each sliding contact of each joint 21, 22, 23 in FIG. Hereinafter, only the structure different from that of the first embodiment will be described, and the common structure will be denoted by the same reference numeral as that of the first embodiment, and the duplicated description will be omitted.

The annular cover 70 is wholly shown in FIG. 15. The annular cover 70 is cut by forming a slit 72 in a part of an annular resin plate, and is provided with two rectangular holes at 180 ° intervals. 71, 71 are formed. Then, as shown in FIG. 16, the annular cover 70 is laid on the sliding surface of the block electrode 40 of the annular electrode 30.

The assembling work of the annular cover 70 is performed as follows. That is, the annular cover 70 is twisted to expand the cut portion (slit 72), and the expanded portion is robot R
The arms (25, 26) are housed inside the annular cover 70, addressed from the side of each arm (25, 26) in FIG.
At this time, the block electrodes 40, 40 are pushed into the recess 43 of the insulating resin case 47, and the annular cover 70 is inserted between the block electrode 40 and the annular electrode 30. Then, as shown in FIG. 17, the rectangular holes 71, 71 in the annular cover 70 and the block electrodes 40, 40 are opposed to each other, and the block electrodes 40 are brought into contact with the annular electrode 30 through the rectangular holes 71. . As a result, the annular cover 70 is laid on the annular electrode 30, covers the sliding path of the block electrode 40 in the annular electrode 30, and locks the rectangular hole 71 in the block electrode 40.

16 and 17, the third joint 23 is shown.
Although only the annular cover 70 attached to the above is shown, the annular cover 70 is similarly attached to the first and second joints 21 and 22.

As described above, according to the present embodiment, the block electrode 40 in the annular electrode 30 is covered by the annular cover 70.
The sliding path is covered and dust and spatter are prevented from adhering to the sliding path. Further, since the annular cover 70 is locked to the block electrode 40 and relatively moves on the annular electrode 30 together with the block electrode 40, it does not interfere with the conduction between the annular electrode 30 and the block electrode 40. Further, since the annular cover 70 is attachable / detachable from the side of the robot R2, it has excellent maintainability.

<Other Embodiments> The present invention is not limited to the embodiments. For example, the embodiments described below are also included in the technical scope of the present invention. Various modifications can be made without departing from the scope of the invention. (1) In the first and second embodiments, the sliding contact attached to the robot is illustrated, but the sliding contact according to the present invention is a robot if it is a pair of members rotatably connected. It may be attached to something other than. Therefore, the sliding contact according to the present invention may be used by being attached to the rotation mechanism portion inside the positioner.

(2) In the first and second embodiments, the ring-shaped electrode 30 has a structure in which the two arc-shaped electrodes 33, 33 are combined, but the ring-shaped electrode has three or more arc-shaped electrodes combined. It may be configured.

(3) In the first and second embodiments, the cleaning groove 34 extends in the radial direction of the annular electrode 30, but the cleaning groove according to the present invention has a sliding area of the block electrode in the annular electrode. Any direction may be used as long as it is a transverse direction.

[Brief description of drawings]

FIG. 1 is a perspective view of a welding system according to a first embodiment of the present invention.

[Fig. 2] Side view of a work holding robot (robot with sliding contacts)

FIG. 3 is a side view of a third joint of the robot.

FIG. 4 is a plan view of a third joint of the robot.

[Fig. 5] Front view of the flange of the robot

FIG. 6A is a plan view of a disc that is a source of an arc electrode. (B) A plan view of an arc-shaped electrode manufactured by cutting a disc.

FIG. 7 is a perspective view showing a state before the annular electrode is attached to the third joint.

FIG. 8 is a perspective view showing a state where an annular electrode is attached to the third joint.

FIG. 9 is a side sectional view of an electrode unit.

FIG. 10 is a partial side sectional view of the terminal block.

FIG. 11 is a front view of the second joint of the robot.

FIG. 12 is a sectional view of a bracket for attaching the annular electrode.

FIG. 13 is a front view of the first joint of the robot.

FIG. 14 is a front view of the base portion.

FIG. 15 is a plan view of an annular cover according to the second embodiment.

FIG. 16: Third robot with annular cover attached
Top view of joint

FIG. 17 is a front view of a robot flange with an annular cover attached.

FIG. 18 is a side view of a conventional welding system.

FIG. 19 is a side sectional view of a positioner having a conventional sliding contact.

[Explanation of symbols]

21 ... 1st rotary joint 22 ... Second rotary joint 23 ... Third rotary joint 24 ... Base part (link) 25 ... 1st arm (link) 26 ... 2nd arm (link) 27 ... Flange (link) 30 ... Ring electrode 33 ... Arc electrode 34 ... Cleaning groove 35 ... Connecting plate 40 ... Block electrode 44 ... Coil spring 50, 51, 56, 57, 58 ... Cable (electric line) 70 ... Annular cover R2 ... Work holding robot (robot with sliding contact)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3C007 AS11 BS09 CV07 CW06 CY02                       CY06 JS02 LV02                 4E001 NB10

Claims (8)

[Claims] 1. An annular electrode that surrounds the outer side of one of the pair of rotatably connected members and is fixed to one of the members, and is fixed to a member opposite to the annular electrode. And a block electrode pressed against a part of the ring-shaped electrode, and the ring-shaped electrode and the block electrode slide along with the relative rotation between the pair of members. A sliding contact for electrically connecting electric paths respectively connected to the block electrode and the block electrode, wherein the annular electrode has a cleaning groove formed across the sliding path of the block electrode. 2. An annular electrode surrounding the outside of one of the pair of members rotatably connected and fixed to any one of the members, and fixed to a member opposite to the annular electrode. And a block electrode pressed against a part of the ring-shaped electrode, and the ring-shaped electrode and the block electrode slide along with the relative rotation between the pair of members. In the sliding contact for conducting between the electric paths respectively connected to the block electrode and the block electrode, the annular electrode is formed by combining a plurality of arc-shaped electrodes in the circumferential direction thereof, with a gap provided between the arc-shaped electrodes,
A sliding contact comprising a cleaning groove that crosses a sliding path of the fixed block in the annular electrode. 3. The sliding contact according to claim 2, wherein the annular electrode is configured to have a circular shape as a whole by combining the plurality of arc-shaped electrodes and the cleaning groove. 4. A connecting plate having both ends fixed to each of the adjacent arc-shaped electrodes and connecting the arc-shaped electrodes with each other in a flush state is provided on a side of a sliding path of the block electrode in the annular electrode. It has been arranged, The claim 2 characterized by the above-mentioned.
Or the sliding contact described in 3. 5. The block electrode is fixed to the member via a coil spring, and a space for allowing tilting of the block electrode is provided around the block electrode. The sliding contact according to any one of claims 1 to 4. 6. An annular cover for covering a sliding path of the block electrode in the annular electrode is laid, and the annular cover is locked to the block electrode. Sliding contact. 7. The annular cover is formed by cutting a part of an annular resin plate, and the cut portion is expanded by deformation of the resin plate so that the member can be received inside the annular cover. The sliding contact according to claim 6, which is characterized in that. 8. A robot with sliding contacts, wherein a robot provided with a plurality of links connected by rotary joints is provided with an electric path, and the electric paths on both sides of the rotary joint are electrically connected by sliding contacts. The moving contact is fixed to an annular electrode surrounding one of the links connected by the rotary joint and fixed to one of the links, and to a link opposite to the annular electrode, And a block electrode pressed against a part of the annular electrode, the annular electrode is a combination of a plurality of arc-shaped electrodes, the gap provided between the arc-shaped electrodes, by the fixed block of the annular electrode A robot with sliding contacts, characterized by having a cleaning groove formed across the sliding path.