KR102548152B1 - Spot welding apparatus - Google Patents

Abstract

[Problem] To change the direction of a spot welding gun without changing the shape of the articulated robot as a whole, thereby improving the productivity of spot welding at a low cost.
[Means of solution] The spot welding apparatus 1 according to the present invention is an articulated robot 10 having a plurality of links 11 to 16 and joints and a plurality of links 11 to 16 of the articulated robot 10 The first rotation axis of the tip link 16 ( A rotation mechanism (30) for rotating the spot welding gun (20) around a second rotation axis (X7) intersecting with (X6) is provided.

Description

Spot welding device {SPOT WELDING APPARATUS}

The present invention relates to a spot welding device, and more particularly, to a spot welding device implemented by mounting a spot welding gun on the front end of an articulated robot.

For example, in the production process of automobiles, spot welding is often used when joining steel plates (works) to each other. This spot welding is typically performed using an articulated robot and a spot welding gun attached to the tip of the articulated robot. In this case, the multi-joint robot drives and controls one electrode of the spot welding gun in the direction of the pressing axis, and supplies a large current between the pair of electrodes from the timer contactor through a transformer in a state where the workpiece is bitten between the pair of electrodes to generate resistance. Try to join the workpiece by

Also, in this type of spot welding, welding work is performed by changing the shape of the entire articulated robot including the position and direction of the spot welding gun according to the welding instruction position (welding part) set in advance for each workpiece, and approaching the spot welding gun to the welding instruction position. are doing

However, when this kind of spot welding is performed on the white body of a vehicle, the front end of an articulated robot including a spot welding gun is entered into the inside of the vehicle through the window frame of the windshield, depending on the welding part. It is necessary to approach the spot welding gun to the welded area from the inside. For this reason, for example, in Patent Document 1, a spot welding device implemented by mounting the spot welding gun in a posture in which the pressurizing axis of the spot welding gun perpendicularly crosses the rotational axis of the foremost link (wrist) of the articulated robot has been proposed. . By attaching the side part of the spot welding gun to the front end of the articulated robot in such a posture, the front end of the articulated robot can be miniaturized compared to the case where the spot welding gun is mounted such that the pressure shaft of the spot welding gun and the rotation axis of the tip link coincide, for example. do. Through this, it is possible to improve the handling of the spot welding gun performed inside the vehicle. In other words, when considering entering the spot welding gun into the vehicle through the window frame of the vehicle's windshield, the tip link of the articulated robot and the spot welding gun are placed in series (the rotation axis of the tip link and the pressurizing axis of the spot welding gun coincide). If so), depending on the approach posture, it is impossible to enter unless the window frame size is secured by the sum of the axial dimensions of the tip link and the spot welding gun. In contrast, when the spot welding gun is mounted on the front link in the position described in Patent Document 1, it is possible to enter the vehicle as long as the axial dimension of the spot welding gun is less than the window frame size. In addition, since the size of the front end of the articulated robot is also compact, it is relatively easy to move the spot welding gun inside the vehicle or to change its posture or direction.

JP 2001-179463 A

However, due to the fact that the posture or direction of the spot welding gun is designed according to the shape of the entire articulated robot, for example, when trying to change the posture or direction of the spot welding gun inside the vehicle, the shape of the entire articulated robot must be changed. In this case, in order to avoid interference between the articulated robot and the vehicle, it is necessary to take the spot welding gun out of the vehicle once and then set the shape of the entire articulated robot so that the spot welding gun takes a predetermined posture or direction inside the vehicle. Occurs. In this case, since it takes more time to weld a plurality of positions, it becomes difficult to meet the demand of line contact. As a result, it becomes difficult to reduce production costs.

In view of the above circumstances, in the present invention, it is necessary to solve the problem of providing a spot welding device capable of changing the direction of a spot welding gun without changing the shape of the entire joint robot, thereby improving the productivity of spot welding at low cost. take it as a technical task.

The solution to the above problems is achieved by a spot welding apparatus related to the present invention. That is, this welding device includes an articulated robot having a plurality of links and joints, a spot welding gun mounted on a tip link located at a tip of the articulated robot among the plurality of links, and a blocking link connected to the proximal end of the tip link. And, the tip link rotates around the predetermined first rotational axis without changing the posture with respect to the blocking link, and the spot welding gun is a spot welding device mounted on the tip link in a posture in which the pressure shaft of the spot welding gun and the first rotational axis intersect. In the present invention, it is characterized by additionally comprising a rotation mechanism for rotating the spot welding gun around a second rotational axis intersecting the first rotational axis without changing the position of the spot welding gun with respect to the tip link.

In this way, the present invention determines the mutual posture of a plurality of links constituting the articulated robot, and furthermore, a new rotational axis that intersects the rotational axis (first rotational axis) of the tip link separately from the rotational axis that determines the overall shape of the articulated robot. A rotational shaft (second rotational shaft) is provided and a rotation mechanism for rotating the spot welding gun around the rotational shaft is provided. Because of this, the trajectory (radius of rotation) of the part that rotates with the spot welding gun can be reduced to a small size, so even if the front end of the articulated robot has entered the inside of the vehicle, for example, the front end of the link to which the spot welding gun is mounted is further reduced. By rotating only the part, the direction of the spot welding gun can be changed while avoiding interference with the surroundings. Accordingly, it is possible to perform welding on a plurality of welding parts having different approach directions from inside the vehicle without repeating entering into and out of the vehicle. In this way, if welding can be performed in multiple positions with as small an operation as possible, the interference area and interference time with other articulated robots can be eliminated or mitigated. It is possible to increase the work efficiency per device (articulated robot), to achieve workability improvement and cost reduction at the same time.

In addition, in the spot welding device according to the present invention, when the spot welding gun has a pair of electrodes, the reference point serving as a reference point for controlling the articulated robot may be located at the center of the tip of the fixed-side electrode among the pair of electrodes. Also, in this case, the rotation axis of the rotation mechanism may be set so that the rotation axis passes through the center of the distal end of the fixed-side electrode.

In this way, by providing the reference point for controlling the articulated robot at the center of the front end of the electrode on the fixed side among the pair of electrodes of the spot welding gun, it is possible to control the welding position with high accuracy. In addition, the reference point does not change even when the spot welding gun is rotated by the rotation mechanism by setting the rotation shaft so that the rotation shaft of the rotation mechanism passes through the center of the front end of the fixed-side electrode serving as the reference point. Therefore, even an articulated robot having a newly provided rotation mechanism can easily control the position of the robot.

Further, in the spot welding apparatus according to the present invention, the rotary mechanism has a casing, and the casing may rotate around the second rotary shaft together with the spot welding gun.

In this way, when the casing of the rotating mechanism is rotated together with the spot welding gun, components of the rotating mechanism accommodated in the casing, such as a motor, can always be kept at the same position in the circumferential direction with respect to the spot welding gun. Therefore, for example, if there is a part protruding outward in the radial direction with respect to the rotational axis (second rotational axis) of the spot welding gun, such as the welding gun body of the spot welding gun forming an arc, the motor, etc. is installed at the same position in the circumferential direction as the protruding part By doing so, regardless of the direction (phase of rotation) of the spot welding gun, it is possible to maintain a state in which the parts protruding outward in the radial direction with respect to the rotational axis (third rotational axis) of the spot welding gun are always concentrated on one side in the circumferential direction. Therefore, even when the spot welding gun is rotated in any direction, the degree of freedom of arrangement of the spot welding gun can be further increased by reducing the substantial interference area between the spot welding gun and the surroundings of the rotating mechanism.

In addition, in the spot welding device according to the present invention, the rotation mechanism has a rotation drive unit for generating rotation driving force and a rotation transmission mechanism for transmitting the rotation drive force generated by the rotation drive unit to the spot welding gun, and the rotation transmission mechanism is connected to the spot welding gun and the tip link. It is disposed between the rotation drive unit and the rotation transmission mechanism may be disposed in parallel.

In this way, by arranging the rotation transmission mechanism between the spot welding gun and the tip link and simultaneously disposing the rotation drive unit in parallel with the rotation transmission mechanism, for example, placing the rotation transmission mechanism and the rotation drive unit in series (arranged in the axial direction) Compared to the case, the axial dimension of the rotating mechanism can be reduced. Through this, the front end of the articulated robot including the spot welding gun and the rotating mechanism can be made more compact, so the ease of handling (movement freedom) of the spot welding gun in areas where the range of motion is restricted, such as inside a vehicle, is further improved. can be raised

As described above, since the posture of the spot welding gun can be changed without changing the overall shape of the articulated robot through the spot welding apparatus related to the present invention, the productivity of spot welding can be improved at low cost.

Fig. 1 is a front view showing the entire configuration of a spot welding apparatus according to an embodiment of the present invention.
Fig. 2 is an enlarged cross-sectional view of a main part of the spot welding apparatus shown in Fig. 1;
Fig. 3 is a side view of the rotating mechanism shown in Fig. 2 from the direction A;
4 is a view showing an example of a spot welding method using the welding device shown in FIG. 1;
Figure 5 is a BB cross-sectional view of Figure 4, (a) is a cross-sectional view when the spot welding gun is approached to the welding part on either side of the vehicle, (b) is a cross-sectional view in a state where the spot welding gun is rotated and the direction is changed 180 degrees , (c) is a cross-sectional view when the spot welding gun in which the direction is changed is approached to the welding part on the left and right sides of the vehicle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, contents of a spot welding apparatus and a spot welding method using the apparatus according to an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a front view showing the entire configuration of a spot welding apparatus 1 according to the present embodiment. As shown in FIG. 1, this spot welding device 1 is an articulated robot 10, a spot welding gun 20 mounted on the front end of the articulated robot 10, and a spot welding gun 20 mounted on a predetermined rotation axis. It mainly includes a rotating mechanism 30 for rotating around. Hereinafter, the configuration of the rotating mechanism 30 will be mainly described.

The articulated robot 10 is a robot arm having a plurality of links and joints and has, for example, 5 to 7 degrees of freedom. In the present embodiment, the articulated robot 10 is a vertical articulated robot with 6 degrees of freedom and includes a first link 11 rotatable around a rotational axis X1 in a vertical (ie, vertical) direction with respect to the floor surface 2 and a first A second link 12 connected to the front end of the link 11 and rotatable around the horizontal axis of rotation X2 and a second link 12 connected to the front end of the second link 12 and rotatable around the horizontal axis of rotation X3 Of the third link 13 and the fourth link 14 connected to the front end of the third link 13 and rotatable around the rotation axis X4 intersecting the rotation axis X3 and perpendicular to the fourth link 14. A fifth link 15 connected to the front end side and rotatable around a horizontal rotation axis X5 and a rotation axis X6 connected to the front end side of the fifth link 15 and perpendicularly intersecting the rotation axis X5 It has a possible sixth link (16).

Among them, the second link 12, the third link 13, and the fifth link 15 are links (first link 11, second link 12, and fourth link) connected from the base end side, respectively. (14)) rotates around the rotation axes X2, X3, and X5 so that the joint angles θ1, θ2, and θ4 change. In addition, the fourth link 14 and the sixth link 16 do not change their attitudes relative to the third link 13 and the fifth link 15 connected from the base end side (in this embodiment, the third link 13 ) and the joint angles θ3 and θ5 of the fifth link 15 are constant at 180 °), and rotate around the rotation axes X4 and X6 perpendicularly intersecting each rotation axis X3 and X5.

The rotational drive of each link 11 to 16 around the above rotational axes X1 to X6 is controlled by a robot controller not shown. Through this, it is possible to control the spot welding gun 20 mounted on the tip of the articulated robot 10, specifically, the sixth link 16, which is the most tip-side link, in a predetermined position and posture. In addition, the movement trajectory of the spot welding gun 20 reaching the predetermined position and posture can be controlled. In addition, as will be described later, when the spot welding gun 20 has a pair of electrodes 23a and 23b and the pair of electrodes 23a and 23b are configured to pressurize and energize the welding area, the articulated robot 10 ) may be provided at the center of the front end of the other electrode 23b, which is a fixed side electrode, among the pair of electrodes 23a and 23b. In that case, the rotation axis X7 of the rotation mechanism 30 to be described later may be set so that the rotation axis X7 passes through the center of the tip of the other electrode 23b.

The spot welding gun 20 has a welding gun body 21, a pressing part 22, and a pair of electrodes 23a and 23b. The welding gun body 21 has an arcuate shape as a whole, and one electrode 23a and the other electrode 23b are respectively installed at both ends thereof. The pressing unit 22 has a ball screw unit 25 as a driving direction converting unit for converting rotation of the pressing motor 24 and the pressing motor 24 into direct motion, as shown in FIG. 2, for example. . The ball screw part 25 is composed of a nut part 26 and a bolt part 27, and the input gear part 28 mounted on the drive shaft 24a of the pressing motor 24 and the output machine installed on the outer periphery of the nut part 26 The fisherman 26a is connected via the belt 29 (see Figs. 2 and 3). Further, one electrode 23a is attached to the distal end side of the bolt portion 27 with the attachment 31 interposed therebetween. Due to this, when the rotational driving force is generated by the pressing motor 24, the rotational driving force is transmitted from the input gear unit 28 through the belt 29 to the output gear unit 26a and further to the nut unit 26. And through the cooperation of the nut part 26 and the bolt part 27, the rotational driving force is transmitted to the bolt part 27 as a direct driving force, so that the bolt part 27 advances and retreats along the pressing shaft Y1, so that the attachment ( 31), one electrode 23a attached to the bolt part 27 is movable along the pressing shaft Y1. In addition, the nut part 26 is supported by the first casing 33 with the first bearing part 32 therebetween, and the bolt part 27 is attached to the first casing 33 with the attachment 31 therebetween. is supported by Further, the motor for pressurization (24) is housed in the second casing (34), and the second casing (34) is fixed to the first casing (33).

In the present embodiment, as shown in FIGS. 1 and 2, a transformer 35 is installed on the outer circumference of the welding gun body 21 (the outer circumference here refers to the outside in the radial direction when the pressing shaft Y1 is the center). is attached. Due to this, the transformer 35 can rotate integrally with the spot welding gun 20 due to the rotation mechanism 30 described later.

Movement control in the direction of the pressing axis Y1 in the spot welding gun 20 having the above configuration, that is, driving control of the pressing motor 24 may be controlled through a robot control device not shown, similarly to the articulated robot 10. It may be controlled through a control device separate from the robot control device (for example, a control device dedicated to the spot welding gun 20, not shown).

The rotation mechanism 30 rotates the spot welding gun 20 around the rotation axis X7 intersecting the rotation axis X6 of the sixth link 16 without changing the posture of the spot welding gun 20 with respect to the sixth link 16. ) to rotate (see FIG. 1). In this embodiment, the rotating mechanism 30 is configured to freely rotate the spot welding gun 20 in all directions around the rotating shaft X7. Here, the rotation axis X6 corresponds to the first rotation axis related to the present invention, and the rotation axis X7 corresponds to the second rotation axis related to the present invention. In addition, the sixth link 16 corresponds to the leading link related to the present invention, and the fifth link 15 corresponds to the blocking link related to the present invention.

As shown in FIGS. 2 and 3 in the present embodiment, the rotary mechanism 30 implementing the above action includes a rotational motor 36 as a rotational driving unit for generating a rotational driving force and rotation generated by the rotational motor 36 It has a third casing 38 for accommodating a rotation transmission mechanism 37 and a rotation motor 36 for transmitting driving force to the spot welding gun 20. Here, the rotation transmission mechanism 37 is composed of an input unit 39, a reducer 40, and an output unit 41, and the first gear unit 42 mounted on the drive shaft 36a of the rotation motor 36 and the input unit A second gear portion 39a provided on the outer periphery of 39 is connected with a belt 43 therebetween (see Figs. 2 and 3). The input part 39 is fixed to the rotating part 40a of the reducer 40, and the fixing part 40b of the reducer 40 is fixed to the tip link (the sixth link 16) with the connection part 44 therebetween. there is. The reduction gear 40 is configured to reduce the rotational force input to the rotation unit 40a with the input unit 39 interposed therebetween and output it to the output unit 41 . In addition, at this time, as shown in FIG. 2, even if the third casing 38 integrally formed with the output unit 41 supports the input unit 39 with the second bearing unit 45 therebetween so as to freely rotate. free This second bearing portion 45 may support only the radial direction, or may support both the radial and thrust directions.

Also, the output unit 41 is integrally formed with the third casing 38, and the third casing 38 is fixed to the first casing 33 of the spot welding gun 20. Through this, when the rotational driving force is generated by the rotational motor 36, this rotational driving force is transmitted from the first gear unit 42 to the second gear unit 39a with the belt 43 interposed therebetween to the input unit 39. It is passed on. And the rotational driving force input to the input unit 39 is decelerated by the reducer 40 and output to the output unit 41, and the third casing 38 integrally formed with the output unit 41 is the spot welding gun 20 together with the first casing 33 of the rotation axis X7 of the rotation transmission mechanism 37, that is, to rotate around the rotation axis X7 of the rotation mechanism 30. At this time, the rotation axis X7 of the rotation mechanism 30 and the rotation axis X6 of the tip link (the sixth link 16) cross at a vertical angle (see Fig. 1). Also, as shown in FIG. 2, the pressure axis Y1 of the spot welding gun 20 and the rotation axis X7 of the rotation mechanism 30 coincide.

Further, in this embodiment, as a rotation drive unit, a rotation motor 36 and a rotation transmission mechanism 37 are arranged in parallel (see Fig. 2). In other words, the rotation motor 36 and the rotation transmission mechanism 37 are arranged so that the rotation shaft X7 of the rotation transmission mechanism 37 and the rotation shaft X9 of the rotation motor 36 are parallel. In addition, at this time, from the viewpoint of reducing the area of substantial interference between the spot welding gun 20 and the surroundings, as shown in FIGS. 2 and 3, the pressure motor 24 and the rotation motor 36 are positioned side by side in the circumferential direction. It is preferable to dispose them so as to do so, and also, between these pressing motors 24 and rotational motors 36 between the transformer 35 and the rotation transmission mechanism 37 (or the ball screw portion 25 constituting the pressing portion 22) It is preferable to excrete between and). At this time, the rotation axis X8 of the motor 24 for pressure, the rotation axis X9 of the rotation motor 36, and the rotation axis X7 of the rotation mechanism 30 are in a mutually parallel relationship.

Rotation control of the spot welding gun 20 around the rotation axis X7 of the rotation mechanism 30 of the above configuration, here, the driving control of the rotation motor 36 is a robot control not shown similarly to the articulated robot 10. It may be controlled through the device, and it may be controlled through a separate control device from the robot control device (eg, not shown, but a control device dedicated to the rotating mechanism 30).

Next, an example of spot welding using the spot welding apparatus 1 having the above configuration will be described mainly with reference to FIGS. 4 and 5.

Fig. 4 is a perspective view of the main part of the spot welding apparatus 1 when approaching a predetermined part of the vehicle W as a workpiece according to the present embodiment. In addition, Fig. 5 is a cross-sectional view showing the main part of the operation when the front end of the spot welding device 1 approaches the welding parts Wc1 and Wc2 of the side member Wa and the roof member Wb of the vehicle W as predetermined parts. am. In this way, when the welding parts Wc1 and Wc2 exist on the left and right sides of the roof member Wb constituting the vehicle W, first, the articulated robot 10 is driven and controlled to drive and control the window frame on the windshield side of the vehicle W ( In Wd), the front end of the spot welding device 1 enters the interior space We of the vehicle W. And, as shown in FIG. 5 (a), the front end of the spot welding device 1 is raised to weld either the left or right (for example, the welded portion Wc1 on the right side of the vehicle W) with a pair of electrodes ( It is introduced between 23a and 23b). This operation is performed in a state where the opening of the spot welding gun 20 (the opening of the arcuate welding gun body 21) is directed to the right side of the vehicle W (the left side in Fig. 5(a)).

After that, by driving control of the press motor 24, one electrode 23a attached to the bolt part 27 of the ball screw part 25 is raised along the press shaft Y1, and the other electrode 23b and The welding portion (Wc1) is sandwiched between and pressurized. Then, spot welding is performed on the welding portion Wc1 by supplying current between the pair of electrodes 23a and 23b from the transformer 35 while controlling the pressing force and controlling the supply current.

In this way, after spot welding to one of the welded parts Wc1 is completed, the front end of the spot welding device 1 is taken out from the welded part Wc1, and specifically, in the left direction of the vehicle W (Fig. 5 (a) In , it moves to the right), then descends, and then changes only the direction of the spot welding gun 20 without changing the position and attitude of the articulated robot 10 as a whole. In more detail, a rotating mechanism ( 30) is driven and the spot welding gun 20 connected to the rotating mechanism 30 is rotated by a predetermined phase (here, 180°) around the rotating shaft X7. Through this, the direction of the opening of the spot welding gun 20 changes from the right side of the vehicle W to the left side (from a state drawn with a solid line in FIG. 5(b) to a state drawn with a two-dot chain line). The aforementioned operation of changing the direction of the spot welding gun 20 is performed while the spot welding gun 20 is disposed in the inner space We of the vehicle W.

After changing the direction of the spot welding gun 20 in this way, as shown in FIG. A welding portion Wc2 located on the left side is introduced between the pair of electrodes 23a and 23b. This operation is performed with the opening of the spot welding gun 20 (the opening of the arcuate welding gun body 21) facing the left side of the vehicle W (right side in Fig. 5(c)).

After that, through the driving control of the motor 24 for pressurization, one electrode 23a attached to the bolt part 27 of the ball screw part 25 is raised along the pressurization shaft Y1, and the other electrode 23b and The welded portion Wc2 is sandwiched between and pressurized. Then, while controlling the pressing force, a current is supplied from the transformer 35 between the pair of electrodes 23a and 23b, and spot welding is performed on the welding portion Wc2 by controlling the supply current.

As described above, in the present invention, apart from the rotation axes X1 to X6 that determine the mutual posture of the plurality of links 11 to 16 constituting the articulated robot 10, the tip link (here, the sixth link 16) A new rotation axis X7 intersecting the rotation axis X6 is provided, and a rotation mechanism 30 for rotating the spot welding gun 20 around the rotation axis X7 is provided (see Fig. 1). Through this, it is possible to reduce the trajectory (radius of rotation) of the part rotating together with the spot welding gun. Therefore, for example, as shown in FIG. 4, even when the tip of the spot welding device 1 enters the inner space We of the vehicle W, the tip link to which the spot welding gun 20 is mounted (the sixth link) (16)), the direction of the spot welding gun 20 can be changed while avoiding interference with surroundings only by rotating only the distal end side portion. Therefore, welding can be performed on the plurality of welding parts Wc1 and Wc2 approaching from the inside of the vehicle W in different directions without repeatedly entering into the vehicle W and exiting the vehicle W. If welding can be performed on multiple parts with as little movement as possible, the interference area and interference time with other articulated robots can be eliminated or alleviated, Even in the production of a vehicle W having a small lateral dimension), work efficiency per spot welding device 1 (articulated robot 10) can be increased, and workability improvement and cost reduction can be achieved at the same time.

In addition, in this embodiment, the rotation transmission mechanism 37 constituting the rotation mechanism 30 is disposed between the spot welding gun 20 and the tip link (the sixth link 16), and at the same time, the rotation motor as a rotation drive unit (36) was arranged in parallel with the rotation transmission mechanism (37). By arranging this, the axial dimension of the rotation mechanism 30 can be reduced compared to the case where, for example, the rotation transmission mechanism 37 and the rotation motor 36 are arranged in series (arranged in the direction of the rotation axis X7). can be scaled down Through this, since the front end of the spot welding device 1 (articulated robot 10) including the spot welding gun 20 and the rotating mechanism 30 can be made more compact, for example, the interior space of the vehicle W (We) can further increase the handling (movement freedom) of the spot welding gun 20 in an area where the range of motion is restricted.

Further, in the present embodiment, while disposing the rotary motor 36 on the same side in the circumferential direction as the arcuate welding gun body 21 (see Figs. 2 and 3), the rotation motor 36 is accommodated The casing (third casing 38) of the mechanism 30 was rotated like the spot welding gun 20. With this configuration, regardless of the direction of the spot welding gun 20, the part protruding outward in the radial direction with respect to the rotating shaft X7 of the spot welding gun 20 at all times (welding gun body 21, rotary motor 36, etc.) ) can be concentrated on one side in the circumferential direction. Therefore, even when the spot welding gun 20 is rotated in any direction, the area of substantial mutual interference between the spot welding gun 20 and the surroundings of the rotating mechanism 30 is reduced to a small extent, and the freedom of operation and placement of the spot welding gun 20 can be further increased.

In particular, in this embodiment, the transformer 35 is fixedly disposed on the outer periphery of the welding gun body 21, and the pressure motor 24 and the rotation between the transformer 35 and the ball screw 25 as a motion direction conversion unit. A dedicated motor 36 is disposed, and the transformer 35 and both motors 24 and 36 are rotated integrally with the spot welding gun 20 around the rotary shaft X7. Through this, all of the parts protruding in the radial direction from the rotary shaft (X7) of the spot welding gun 20 are concentrated on one side in the circumferential direction, and the relationship between the transformer 35 and the pressing part 22 (ball screw part 25) The dead space in the radial direction inevitably generated between the motors 24 and 36 may be used as an accommodation space. Accordingly, it is possible to further reduce a substantial interference area between the spot welding gun 20 and the rotation mechanism 30 .

In addition, in the present embodiment, the reference point of the spot welding device 1 (articulated robot 10) is set on the pressure axis Y1, and the spot welding gun ( 20) and the rotating mechanism 30 were configured. In this configuration, the reference point before and after rotating the spot welding gun 20 by the rotary mechanism 30 does not change. Therefore, even if the rotation mechanism 30 is added, complexity of control of the articulated robot 10 can be avoided and control can be performed as before.

Although one embodiment of the present invention has been described above, the spot welding apparatus related to the present invention may take a configuration other than the above within a range not departing from the gist.

For example, in the above embodiment, the rotation mechanism 30 has a rotation motor 36, a rotation transmission mechanism 37, and a third casing 38 accommodating the rotation motor 36, and the rotation transmission mechanism 37 Although the case is exemplified by the input unit 39, the reducer 40, and the output unit 41, it is also possible for the rotation mechanism 30 to take a configuration other than the above. For example, depending on the type (output) of the rotational motor 36, the rotational driving force of the rotational motor 36 is directly transmitted to the third casing 38 by omitting the reduction gear 40 or the rotation transmission mechanism 37. also free

Further, in the above embodiment, the rotational motor 36 is housed in the third casing 38 and the third casing 38 is rotated around the rotational shaft X7, thereby converting the rotational motor 36 to the spot welding gun 20. A case of rotating around the rotational axis X7 is exemplified, but the rotational aspect is not limited thereto. For example, the rotational motor 36 is fixed to the fixed side (fixed side to the tip link) of the rotation mechanism 30, and the spot welding gun 20 is moved along the rotation shaft X7 without rotating the rotational motor 36. It's okay to rotate it around. In the same way, the transformer 35 or the pressure motor 24 is fixed to the fixed side of the rotation mechanism 30, and the spot welding gun 20 is mounted on the rotating shaft without rotating the transformer 35 and the pressure motor 24. (X7) It is okay to rotate it around.

In addition, in the above embodiment, the case where the rotation axis X7 of the spot welding gun 20 and the rotation axis X6 of the tip link (the sixth link 16) vertically intersect (see FIG. 1) is exemplified, but of course the rotation axis (X7) and the axis of rotation (X6) can be any angle as long as they are not parallel. That is, as long as the angle between the rotation axis X7 and the rotation axis X6 is greater than 0° and less than 180°, the direction of the rotation axis X7 can be arbitrarily set. In addition, the same is true for the angle formed between the pressure axis Y1 of the spot welding gun 20 and the rotation axis X6 of the sixth link 16, and the angle formed between the pressure axis Y1 and the rotation axis X6 is greater than 0°. As long as it is smaller than 180 °, the direction of the pressing axis Y1 can be arbitrarily set.

In addition, in the above embodiment, the case where the spot welding gun 20 and the rotating mechanism 30 are configured so that the pressing shaft Y1 and the rotating shaft X7 coincide with each other is exemplified, but the pressing shaft Y1 and the rotating shaft X7 are offset from each other. It doesn't matter if it's set in position.

In addition, in the above description, a case in which the spot welding apparatus 1 related to the present invention is applied to the side member Wa and the welding parts Wc1 and Wc2 located on the left and right of the loop member Wb constituting the vehicle W is exemplified. However, the present invention can also be appropriately applied to welds between copper plates constituting the vehicle W other than those described above (such as welds provided on the left and right side panel members of the rear of the vehicle). Of course, the present invention can be applied to parts that can be spot-welded other than the vehicle W, and can be particularly suitably applied to a joint between thin metal parts that need to be approached from the inside of the bag structure.

1 spot welding device
10 articulated robot
Links 11 to 16
20 spot welding gun
21 welding gun body
22 Pressing part
23a, 23b electrodes
24 Pressurization motor
25 ball screw part
26 Nut part
27 bolt part
29, 43 belt
30 rotating mechanism
31 attachment
32 1st bearing part
33, 34 casing (pressing part)
35 trans
36 Rotary Motor
37 Rotation Transmission Mechanism
38 Casing (rotating mechanism)
39 input
40 reducer
40a rotating part
40b fixing part
41 output
44 connection
45 2nd bearing part
W vehicle
Wa side member
Wb loop member
Wc1, Wc2 welding area
window frame of a wd vehicle
The interior space of We vehicle
X1~X6 axis of rotation (articulated robot)
X7 rotary shaft (rotary mechanism)
X8 rotation axis (motor for pressure)
Y1 pressure shaft (motor for rotation)
θ1~θ5 joint angle

Claims (3)

An articulated robot having a plurality of links and joints and a spot welding gun mounted on a tip link located at a tip of the articulated robot among the plurality of links,
A blocking link is connected to the proximal side of the tip link, and the tip link is an angle formed by the tip link and the blocking link when viewed from a direction perpendicular to a virtual plane including a predetermined first rotation axis serving as a rotation axis of the tip link. rotates around the first rotational axis while always being fixed at 180 degrees,
In the spot welding device, the spot welding gun is mounted on the tip link in an attitude in which the pressing shaft of the spot welding gun and the first rotational shaft intersect,
A structure in which a rotating mechanism for rotating the spot welding gun around a second rotating shaft intersecting the first rotating shaft is additionally provided, and the rotating mechanism maintains a constant attitude of the second rotating shaft relative to the first rotating shaft. Characterized in that it constitutes,
spot welding device. According to claim 1,
The spot welding gun has a welding gun body forming an arcuate shape,
The rotary mechanism has a casing and a rotary motor accommodated in the casing to generate a rotary driving force around the second rotary shaft of the spot welding gun,
The rotational shaft of the rotational motor is disposed at a position parallel to the second rotational shaft, and the rotational motor is on the same side as the spot welding gun body in the circumferential direction of the second rotational shaft and at the same time in the axial direction of the second rotational shaft. is placed in a different location in
The casing and the rotating motor rotate around the second rotating shaft together with the spot welding gun.
spot welding device. According to claim 2,
The rotation mechanism includes a rotation transmission mechanism for transmitting the rotation driving force generated by the rotation motor to the spot welding gun,
The pressure motor and the rotation motor of the spot welding gun are disposed in parallel in the circumferential direction of the second rotation shaft,
A transformer is attached to the outer circumference of the spot welding gun body, and the pressure motor and the rotation motor are disposed radially inside the second rotational shaft than the transformer,
spot welding device.

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