KR20190113616A - Spot welding apparatus - Google Patents

Abstract

According to the present invention, without a change in the whole shape of an articulated robot, a direction of a spot welding gun can be changed to improve productivity of spot welding at low costs. According to the present invention, a spot welding apparatus (1) comprises: an articulated robot (10) having a plurality of links (11-16) and joints; and a spot welding gun (20) mounted on a front link (16) placed in a front end of the articulated robot (10) of the links (11-16). Moreover, the spot welding apparatus more comprises a rotating mechanism (30) rotating the spot welding gun (20) around a second rotating axis (X7) crossing a first rotating axis (X6) of the front link (16) without changing a posture of the spot welding gun (20) with respect to the front link (16).

Description

Spot welding device {SPOT WELDING APPARATUS}

The present invention relates to a spot welding apparatus, and more particularly, to a spot welding apparatus implemented by mounting a spot welding gun at the tip of an articulated robot.

For example, spot welding is often used in the production process of automobiles when steel sheets (work) are joined together. This spot welding is typically performed using a spot welding gun attached to the tip of the articulated robot and the articulated robot. In this case, the articulated 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 through a transformer in a timer contactor while the workpiece is bitten between the pair of electrodes. Work joining by means of.

In this type of spot welding, the welding operation is performed by changing the shape of the entire articulated robot including the posture and the direction of the spot welding gun in accordance with a preset welding instruction position (welding site) for each work and approaching the spot welding gun at the joint instruction position. Doing.

However, when this type of spot welding is performed on the white body of the vehicle, the tip of the articulated robot, including the spot welding gun, is inserted into the vehicle through the window frame of the front glass, depending on the welding portion. There is a need to approach the spot welding gun from the inside to the weld. For this reason, for example, Patent Literature 1 proposes a spot welding device implemented by mounting a spot welding gun in a position in which the pressure axis of the spot welding gun perpendicularly intersects the rotation axis of the link (wrist) at the leading end of the articulated robot. . By attaching the side of the spot welding gun to the front end of the articulated robot in such a posture, for example, the tip of the articulated robot becomes smaller compared to the case where the spot welding gun is mounted so that the pressure axis of the spot welding gun coincides with the rotation axis of the tip link. do. Through this, the handleability of the spot welding gun performed in the vehicle can be improved. In other words, when the spot welding gun enters the inside of the vehicle through the window frame of the vehicle's front glass, the tip link of the articulated robot and the spot welding gun are arranged in series (the rotation axis of the tip link coincides with the pressing axis of the spot welding gun). According to the approach posture, it is not possible to enter unless the window frame dimensions are secured by the sum of the axial dimensions of the tip link and the spot welding gun. On the other hand, when the spot welding gun is attached to the tip link in the posture described in Patent Literature 1, the spot welding gun can 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 distal end portion of the articulated robot becomes compact, it is relatively easy to move the spot welding gun inside the vehicle or to change the posture or direction.

JP 2001-179463 A

However, since the posture or direction of the spot welding gun is designed according to the shape of the entire articulated robot, for example, when changing the posture or the direction of the spot welding gun inside a vehicle, the shape of the entire articulated robot must be changed. In this case, it is necessary to remove the spot welding gun from the outside of the vehicle and set the shape of the entire articulated robot so that the spot welding gun takes a predetermined posture or direction from the inside of the vehicle to avoid the interference between the articulated robot and the vehicle. Occurs. In this case, it takes more time to weld a plurality of positions, making it difficult to meet the requirements of the line tact. As a result, it is also difficult to reduce production costs.

In view of the above circumstances, in the present invention, it is possible to change the direction of the spot welding gun without changing the shape of the entire articulated robot, and through this, it is necessary to solve the problem of providing a spot welding apparatus which can improve the productivity of spot welding at low cost. Make it a technical task.

Solution of the said subject is achieved by the spot welding apparatus which concerns on this invention. That is, the welding apparatus includes a multi-joint robot having a plurality of links and joints, and a spot welding gun mounted on a tip link positioned at the tip of the articulated robot among the plurality of links, and a blocking link is connected to the proximal end of the tip link. The tip link rotates around a predetermined first axis of rotation without changing the attitude of the blocking link, and the spot welding gun is mounted on the spot welding device mounted to the tip link in a position where the pressure axis of the spot welding gun and the first axis of rotation are crossed. And a rotating mechanism for rotating the spot welding gun about a second rotational axis intersecting the first rotational axis without changing the attitude of the spot welding gun relative to the tip link.

As described above, the present invention is a new cross section that intersects the rotation axis (first rotation axis) of the front end link separately from the rotation axis that determines the mutual attitude of the plurality of links constituting the articulated robot, and further determines the shape of the articulated robot as a whole. A rotary shaft (second rotary shaft) was provided and a rotary mechanism for rotating the spot welding gun around the rotary shaft was provided. Because of this, the trajectory (rotation radius) of the part that rotates together with the spot welding gun can be reduced. For example, even if the tip portion of the articulated robot enters the inside of the vehicle, the tip link of the tip link with the spot welding gun is installed. By rotating only the part, the spot welding gun can be changed to avoid interference with the surroundings. Therefore, the welding can be performed on a plurality of welding sites having different approaches in the vehicle interior without repeating entering and exiting the vehicle. If welding can be performed at multiple positions with the smallest possible operation, the interference area and the interference time with other articulated robots can be eliminated or alleviated. For example, spot welding is also possible in the production of vehicles with small opening dimensions such as light vehicles. The work efficiency per device (multi-joint robot) can be increased, and workability can be improved and cost can be simultaneously achieved.

In the spot welding apparatus according to the present invention, when the spot welding gun has a pair of electrodes, the reference point, which is a reference for controlling the articulated robot, may be at the tip center of the fixed electrode among the pair of electrodes. In this case, the rotating shaft may be set such that the rotating shaft of the rotating mechanism passes through the tip center of the fixed electrode.

Thus, by providing a reference point for controlling the articulated robot at the tip center of the fixed side electrode of the pair of spot welding guns, the welding position can be controlled with high accuracy. The reference point does not change even when the spot welding gun is rotated by the rotary mechanism by setting the rotary shaft so that the rotary axis of the rotary mechanism passes through the tip center of the fixed electrode as the reference point. Therefore, even a multi-articulated robot having a rotating mechanism can easily control the position of the robot.

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

When the casing of the rotary mechanism is rotated together with the spot welding gun in this way, the components of the rotary mechanism accommodated in the casing, such as a motor, can always be maintained in the same position in the circumferential direction with respect to the spot welding gun. Therefore, for example, if there is a part that protrudes radially outward with respect to the rotation axis (second rotation axis) of the spot welding gun, such as an arc-shaped spot welding gun body, the motor is disposed at the same position in the circumferential direction. By doing so, it is possible to maintain a state in which a portion protruding radially outward with respect to the rotation axis (third rotation axis) of the spot welding gun is concentrated on one side in the circumferential direction at all times regardless of the direction (rotational phase) of the spot welding gun. Therefore, even when the spot welding gun is rotated in any direction, the degree of freedom of the spot welding gun can be further increased by reducing the area of substantial interference with the surroundings of the spot welding gun and the rotating mechanism.

In addition, in the spot welding apparatus according to the present invention, the rotary mechanism has a rotary driving unit for generating a rotary driving force and a rotary transmission mechanism for transmitting the rotary driving force generated in the rotary driving unit to the spot welding gun, and the rotary transfer mechanism has a spot welding gun and a leading link. It is also provided between the rotary drive unit and the rotary transmission mechanism may be arranged in parallel.

In this way, the rotary transmission mechanism is disposed between the spot welding gun and the tip link, and the rotary drive unit is disposed in parallel with the rotary transfer mechanism, for example, to be arranged in series (arranged in the axial direction) with the rotary transfer mechanism and the rotary drive unit. In comparison with the case, the axial dimension of the rotating mechanism can be reduced. This makes it possible to make the tip end of an articulated robot, including a spot welding gun and a rotating mechanism, more compact, thereby increasing the ease of handling (operation freedom) of the spot welding gun in an area that is restricted by the moving range, for example, inside a vehicle. It can be increased.

As mentioned above, since the spot welding apparatus which concerns on this invention can change the attitude | position of a spot welding gun, without changing the shape of the whole articulated robot, the productivity of spot welding can be improved at low cost.

BRIEF DESCRIPTION OF THE DRAWINGS The front view which shows the whole structure of the spot welding apparatus which concerns on one Embodiment of this invention.
FIG. 2 is an enlarged cross-sectional view showing main parts of the spot welding apparatus shown in FIG.
3 is a side view of the rotating mechanism shown in FIG. 2 in the A direction.
4 is a view showing an example of a spot welding method using the welding apparatus shown in FIG.
Fig. 5 is a cross-sectional view taken along line BB of Fig. 4, (a) is a cross sectional view when the spot welding gun is applied to the welded portions on the left and right sides of the vehicle, and (b) is a sectional view of the spot welding gun being rotated by 180 degrees. and (c) are sectional views when the spot welding gun which changed direction was approached to the welding part of the left and right sides of a vehicle.

EMBODIMENT OF THE INVENTION Hereinafter, the content of the spot welding apparatus which concerns on one Embodiment of this invention, and the spot welding method using this apparatus is demonstrated, referring drawings.

1 is a front view showing the overall configuration of a spot welding apparatus 1 according to the present embodiment. As shown in FIG. 1, the spot welding apparatus 1 is adapted to rotate a spot welding gun 20 and a spot welding gun 20 mounted on the tip of the articulated robot 10 and the articulated robot 10 by a predetermined axis of rotation. It is mainly provided with a rotating mechanism 30 to rotate around. Hereinafter, the configuration of the rotating mechanism 30 will be described.

The articulated robot 10 is a robot arm having a plurality of links and joints, and has 5 to 7 degrees of freedom. In the present embodiment, the articulated robot 10 is a six degree of freedom articulated robot, the first link 11 and the first rotatable around the axis of rotation X1 in the vertical (or vertical) direction with respect to the bottom surface 2. A second link 12 connected to the distal end side of the link 11 and rotatable about a horizontal axis of rotation X2 and a second rotatable connected to the distal end side of the second link 12 and rotatable around a horizontal axis of rotation X3. The third link 13 and the fourth link 14 and the fourth link 14 which are connected to the distal end side of the third link 13 and are rotatable around the rotation axis X4 perpendicularly intersecting with the rotation axis X3. The fifth link 15 which is connected to the distal end side and is rotatable about the horizontal axis of rotation X5 is connected to the distal end of the fifth link 15 and rotates about the axis of rotation X6 that intersects the axis of rotation X5 perpendicularly. It has the sixth link 16 possible.

Among them, the second link 12, the third link 13, and the fifth link 15 are connected to the proximal end (the first link 11, the second link 12, and the fourth link, respectively). (14)) and rotate around each rotation axis X2, X3, X5 so that the joint angles θ1, θ2, and θ4 change. In addition, the 4th link 14 and the 6th link 16 do not change the attitude | position with respect to the 3rd link 13 and the 5th link 15 connected from the base end, respectively (in this embodiment, the 3rd 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 the respective rotation axes X3 and X5.

The rotational drive of each of the links 11 to 16 around the rotation axes X1 to X6 is controlled by a robot control device (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 link on the front end side, in a predetermined position and posture. Further, the movement trajectory of the spot welding gun 20 reaching the predetermined position and posture can be controlled. In addition, in the case where the spot welding gun 20 has a pair of electrodes 23a and 23b and pressurizes the welding site with the pair of electrodes 23a and 23b as described below, the articulated robot 10 May be provided at the tip center of the other electrode 23b which is a fixed side electrode among the pair of electrodes 23a and 23b. In this case, the rotating shaft X7 may be set such that the rotating shaft X7 of the rotating mechanism 30 to be described later passes through the tip center of the other electrode 23b.

The spot welding gun 20 has a welding gun body 21, a pressurizing portion 22, and a pair of electrodes 23a and 23b. The welding gun body 21 has an arcuate shape as a whole, and at one end thereof, one electrode 23a and the other electrode 23b are provided. The pressing section 22 has, for example, a ball screw section 25 as a driving direction converting section for converting the rotation of the pressurizing motor 24 as a driving section and the rotation of the pressurizing motor 24 into linear motion, as shown in FIG. . The ball screw portion 25 is composed of a nut portion 26 and a bolt portion 27 and an output device installed on the outer circumference of the input gear portion 28 and the nut portion 26 mounted on the drive shaft 24a of the pressure motor 24. The fisherman 26a is connected via the belt 29 (refer FIG. 2 and FIG. 3). Moreover, one electrode 23a is attached to the front end side of the bolt part 27 with the attachment 31 interposed. As a result, when the driving force is generated by the pressure motor 24, the driving force is transmitted from the input gear part 28 to the output gear part 26a and the nut part 26 via the belt 29. The rotational driving force is transmitted to the bolt portion 27 as a linear force through the cooperation of the nut portion 26 and the bolt portion 27 so that the bolt portion 27 moves forward and backward along the pressing shaft Y1 and thus the attachment ( One electrode 23a attached to the bolt portion 27 via 31 is able to move along the pressing shaft Y1. In addition, the nut portion 26 is supported by the first casing 33 with the first bearing portion 32 therebetween, and the bolt portion 27 is attached to the first casing 33 with the attachment 31 interposed therebetween. Supported by In addition, the pressurizing motor 24 is accommodated in the second casing 34, and the second casing 34 is fixed to the first casing 33.

In addition, in this embodiment, as shown in FIGS. 1 and 2, the transformer 35 is formed on the outer circumference of the welding gun body 21 (the outer circumference here refers to the radially outer side when the pressure axis Y1 is centered). Is attached. For this reason, the transformer 35 is rotated by being integrated with the spot welding gun 20 by the rotating mechanism 30 mentioned later.

The movement control in the direction of the pressing shaft Y1 in the spot welding gun 20 having the above-described configuration, that is, the driving control of the pressing motor 24 may be controlled through a robot control device (not shown) as in the articulated robot 10. It may be controlled by a control device separate from the robot control device (for example, a control device for spot welding gun 20 not shown).

The rotating mechanism 30 does not change the posture of the spot welding gun 20 with respect to the sixth link 16 but the spot welding gun 20 around the rotation axis X7 intersecting with the rotation axis X6 of the sixth link 16. ) Is rotated (see FIG. 1). In this embodiment, the rotating mechanism 30 is comprised so that the spot welding gun 20 can rotate freely 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 according to the present invention and the fifth link 15 corresponds to the blocking link according to the present invention.

In the present embodiment, the rotation mechanism 30 that implements the above-described rotation is generated by the rotation motor 36 and the rotation motor 36 as the rotation driving unit generating the rotation driving force as shown in FIGS. 2 and 3. It has a rotation transmission mechanism 37 for transmitting the driving force to the spot welding gun 20 and a third casing 38 for receiving the rotary motor 36. 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 and the input unit mounted on the drive shaft 36a of the rotary motor 36. The 2nd gear part 39a provided in the outer periphery of 39 is connected across the belt 43 (refer FIG. 2 and FIG. 3). The input unit 39 is fixed to the rotating unit 40a of the reducer 40, and the fixing unit 40b of the reducer 40 is fixed to the front link (sixth link 16) with the connecting unit 44 interposed therebetween. have. The reducer 40 is configured to reduce the rotational force input to the rotating unit 40a with the input unit 39 interposed therebetween and output the decelerating force to the output unit 41. In this case, as shown in FIG. 2, the input unit 39 may be freely rotated to the third casing 38 integrally formed with the output unit 41 with the second bearing 45 therebetween. It's okay. The second bearing 45 may support only the radial direction, and may support both the radial direction and the thrust direction.

In addition, the output part 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. When the rotary driving force is generated by the rotary motor 36 through this, the rotary driving force is transmitted from the first gear portion 42 to the second gear portion 39a and the input portion 39 with the belt 43 interposed therebetween. Delivered. Then, the rotation driving force input to the input unit 39 is decelerated by the reducer 40, output to the output unit 41, and the third casing 38 formed integrally with the output unit 41 is the spot welding gun 20. It rotates about the rotation axis X7 of the rotation transmission mechanism 37, ie, the rotation axis X7 of the rotation mechanism 30, with the 1st casing 33 of FIG. At this time, the rotary shaft X7 of the rotary mechanism 30 and the rotary shaft X6 of the tip link (sixth link 16) intersect vertically (see Fig. 1). As shown in Fig. 2, the pressing shaft Y1 of the spot welding gun 20 and the rotating shaft X7 of the rotating mechanism 30 coincide with each other.

In addition, in this embodiment, the rotation motor 36 and the rotation transmission mechanism 37 are arrange | positioned in parallel as a rotation drive part (refer FIG. 2). In other words, the rotary motor 36 and the rotary transfer mechanism 37 are arranged such that the rotary shaft X7 of the rotary transfer mechanism 37 and the rotary axis X9 of the rotary motor 36 are parallel to each other. At this time, in view of reducing the substantial interference area between the spot welding gun 20 and the surroundings, the pressurizing motor 24 and the rotating motor 36 are positioned side by side in the circumferential direction as shown in FIGS. 2 and 3. The pressure screw 24 and the rotary motor 36 may be disposed between the transformer 35 and the rotation transmission mechanism 37 (or the ball screw portion 25 constituting the pressing portion 22). Excretion) is preferable. At this time, the rotating shaft X8 of the pressurizing motor 24, the rotating shaft X9 of the rotating motor 36, and the rotating shaft X7 of the rotating mechanism 30 are in parallel with each other.

Rotation control of the spot welding gun 20 around the rotation axis X7 of the rotation mechanism 30 of the above configuration, here drive control of the rotary motor 36 is not shown robot control like the articulated robot 10. It may be controlled through the device, and may be controlled through a control device separate from the robot control device (for example, a control device dedicated to the rotary mechanism 30 although not shown).

Next, an example of spot welding using the spot welding apparatus 1 of the said structure is demonstrated, referring mainly FIG.4 and FIG.5.

4 is a perspective view of a main portion of the spot welding apparatus 1 when approaching a predetermined portion of the vehicle W as a work according to the present embodiment. Fig. 5 is a sectional view of the main part showing the operation when the distal end portion of the spot welding device 1 is approached to the welding portions Wc1 and Wc2 of the side member Wa and the loop member Wb of the vehicle W as a predetermined portion. to be. As described above, when the welding portions Wc1 and Wc2 are present on the left and right sides of the loop members Wb constituting the vehicle W, the articulated robot 10 is driven to control the window frame on the front glass side of the vehicle W. In Wd), the front end of the spot welding apparatus 1 enters the interior space We of the vehicle W. As shown in FIG. 5 (a), the tip of the spot welding device 1 is raised to form a pair of electrodes (for example, a weld Wc1 on the right side of the vehicle W). It introduces between 23a and 23b). This operation is performed in a state where the opening of the spot welding gun 20 (the opening of the welding gun body 21 in the arch state) is directed toward the right side of the vehicle W (left side in Fig. 5 (a)).

Thereafter, one of the electrodes 23a attached to the bolt portion 27 of the ball screw portion 25 is raised along the pressing shaft Y1 by driving control of the pressure motor 24 and the other electrode 23b and the other electrode 23b. The welding site Wc1 is sandwiched between and pressurized. The spot 35 is welded to the welding site Wc1 by supplying a current between the pair of electrodes 23a and 23b in the transformer 35 and controlling the supply current while controlling the pressing force.

In this way, after spot welding to one of the welding sites Wc1 is finished, the tip of the spot welding apparatus 1 is pulled out from the welding site Wc1, and specifically, the left side of the vehicle W (Fig. 5 (a)). In the right) and then descending and then only changes the direction of the spot welding gun 20 without changing the position and posture of the entire articulated robot (10). In more detail, the rotary mechanism connected to the sixth link 16 via the connecting portion 44 as the leading link while maintaining the position and posture of each link 11 to 16 of the articulated robot 10 ( The spot welding gun 20 which drives 30 and connects with the rotating mechanism 30 is rotated about a rotational axis X7 by a predetermined phase (here 180 °). Through this, the direction of the opening of the spot welding gun 20 changes from the right side to the left side of the vehicle W (changes to the state drawn with the dashed-dotted line from the state drawn with the solid line in Fig. 5 (b)). The operation of changing the direction of the spot welding gun 20 described above is performed while the spot welding gun 20 is disposed in the internal space We of the vehicle W.

After changing the direction of the spot welding gun 20 in this manner, as shown in Fig. 5 (c), the front end of the spot welding device 1 is raised by driving control of the articulated robot 10, and the The welding site 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 (opening of the arch-shaped welding gun body 21) facing the left side of the vehicle W (Fig. 5 (c) to the right).

Thereafter, one of the electrodes 23a attached to the bolt portion 27 of the ball screw portion 25 is raised along the pressing shaft Y1 through the driving control of the motor 24 for pressurization and the other electrode 23b and the other. The welding portion Wc2 is sandwiched and pressed in between. The spot 35 is welded to the welding site Wc2 by supplying a current between the pair of electrodes 23a and 23b in the transformer 35 and controlling the supply current while controlling the pressing force.

As described above, in the present invention, the tip link (here, the sixth link 16) is separated from the rotational axes X1 to X6 that determine the mutual attitude of the plurality of links 11 to 16 constituting the articulated robot 10. A new rotary shaft X7 intersecting the rotary shaft X6 was provided to provide a rotary mechanism 30 for rotating the spot welding gun 20 around the rotary shaft X7 (see FIG. 1). Through this, the trajectory (rotation radius) of the portion rotating together with the spot welding gun can be reduced. Thus, for example, as shown in FIG. 4, even when the tip portion of the spot welding apparatus 1 enters the internal space We of the vehicle W, the tip link with the spot welding gun 20 is mounted (sixth link). It is possible to change the direction of the spot welding gun 20 while avoiding interference with the surroundings only by rotating only the portion at the tip side of (16). Therefore, the welding may be performed on the plurality of welding sites Wc1 and Wc2 having different directions to approach inside the vehicle W without repeatedly entering the vehicle W and exiting the vehicle W. If welding can be performed on a plurality of sites with such small movements as possible, the interference area and interference time with other articulated robots can be eliminated or alleviated. For example, the opening dimension (the vertical dimension of the window frame Wd) Also in the production of the vehicle W having a small horizontal dimension, it is possible to increase work efficiency per spot welding device 1 (multi-joint robot 10) and achieve workability improvement and cost reduction at the same time.

In the present embodiment, the rotary transmission mechanism 37 constituting the rotary mechanism 30 is disposed between the spot welding gun 20 and the tip link (sixth link 16), and at the same time, the rotary motor as the rotary drive portion. (36) was disposed in parallel with the rotation transmission mechanism (37). By such arrangement, for example, the axial dimension of the rotary mechanism 30 is compared with the case where the rotary transmission mechanism 37 and the rotary motor 36 are arranged in series (arranged in the direction of the rotation axis X7). Can be shrunk. This makes it possible to make the distal end of the spot welding device 1 (multi-articular robot 10) including the spot welding gun 20 and the rotating mechanism 30 more compact, for example, the internal space of the vehicle W. It is possible to further improve the handleability (degree of freedom of operation) of the spot welding gun 20 in an area restricted by the movable range such as (We).

In the present embodiment, the rotation motor 36 is disposed on the same side in the circumferential direction with the arcuate welding main body 21 (see FIGS. 2 and 3), and the rotation motor 36 is accommodated therein. The casing (third casing 38) of the instrument 30 was allowed to rotate with the spot welding gun 20. By doing so, the portion protruding radially outward with respect to the rotation axis X7 of the spot welding gun 20 (welding gun body 21, the motor for rotation 36, etc.) irrespective of the direction of the spot welding gun 20. ) Can be concentrated on one side in the circumferential direction. Therefore, even in the case where the spot welding gun 20 is rotated in any direction, the freedom of movement and placement freedom of the spot welding gun 20 is reduced by reducing the substantial mutual interference area between the surroundings of the spot welding gun 20 and the rotating mechanism 30. Can be further increased.

In particular, in the present embodiment, the transformer 35 is fixedly arranged on the outer circumference of the welding gun body 21 and the pressurized motor 24 and the rotor are rotated between the transformer 35 and the ball screw 25 as the direction changer of the movement. The dedicated motors 36 were arranged, and these transformers 35 and both motors 24 and 36 were rotated integrally with the spot welding gun 20 about the rotation axis X7. Through this, all the portions protruding in the radial direction from the rotation axis X7 of the spot welding gun 20 are concentrated on one side in the circumferential direction, and the transformer 35 and the pressurizing portion 22 (ball screw portion 25) Radial dead spaces inevitably generated between the two may be used as accommodation spaces of the motors 24 and 36. Therefore, it is possible to further reduce the substantial interference area with the surroundings of the spot welding gun 20 and the rotary mechanism 30.

In addition, in this embodiment, while setting the reference point of the spot welding apparatus 1 (multi-joint robot 10) on the pressurizing shaft Y1, the spot welding gun so that the pressurizing shaft Y1 and the rotating shaft X7 may coincide. 20) and the rotating mechanism 30 was configured. With this configuration, the reference point before and after rotating the spot welding gun 20 with the rotating mechanism 30 does not change. Therefore, even if the configuration of the rotation mechanism 30 is added, it is possible to avoid the complexity of the control of the articulated robot 10 and to control as it is.

As mentioned above, although one Embodiment of this invention was described, the spot welding apparatus which concerns on this invention can also take the structure of that excepting the above within the range which does not deviate from this meaning.

For example, in the above embodiment, the rotary mechanism 30 includes the rotary motor 36, the rotary transfer mechanism 37, and the third casing 38 for receiving the rotary motor 36. Has been exemplified when the input unit 39, the speed reducer 40, and the output unit 41 are configured, of course, the rotary mechanism 30 may have a configuration other than the above. For example, according to the type (output) of the rotary motor 36, the reduction gear 40 or the rotation transmission mechanism 37 is omitted, and the rotation driving force of the rotary motor 36 is directly transmitted to the third casing 38. It is okay.

In the above embodiment, the rotary motor 36 is accommodated in the third casing 38 and the third casing 38 is rotated around the rotation axis X7 to rotate the rotary motor 36 in the spot welding gun 20. While the case of rotating around the axis of rotation (X7) has been exemplified, of course, the rotation is not limited thereto. For example, the rotary motor 36 is fixed to the fixed side of the rotary mechanism 30 (the fixed side to the tip link), and the spot welding gun 20 is rotated without rotating the rotary motor 36. You can rotate it around. In the same manner, the transformer 35 or the pressurizing motor 24 is fixed to the fixed side of the rotary mechanism 30, and the spot welding gun 20 is rotated without rotating the transformer 35 and the pressurizing motor 24. (X7) It may be rotated 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 (sixth link 16) intersect vertically (see FIG. 1), of course, the rotation axis Any angle may be provided as long as X7 and rotation axis X6 are not parallel. That is, the direction of the rotation axis X7 can be arbitrarily set as long as the angle formed by the rotation axis X7 and the rotation axis X6 is larger than 0 ° and smaller than 180 °. The same applies to the angle formed between the pressing shaft Y1 of the spot welding gun 20 and the rotating shaft X6 of the sixth link 16 and the angle formed between the pressing shaft Y1 and the rotating shaft X6 is greater than 0 °. As long as it is smaller than 180 degrees, the direction of the pressing shaft Y1 can be arbitrarily set.

In the above embodiment, the case where the spot welding gun 20 and the rotating mechanism 30 are configured to coincide with the pressing shaft Y1 and the rotating shaft X7 is illustrated, but the pressing shaft Y1 and the rotating shaft X7 are offset from each other. It may be set at a position.

In addition, in the above description, the case where the spot welding apparatus 1 according to the present invention is applied to the side members Wa and the welding portions Wc1 and Wc2 positioned on the left and right of the roof member Wb constituting the vehicle W is illustrated. However, the present invention can also be suitably applied to welding portions (such as welding portions provided on the left and right side panel members of the vehicle rear portion) constituting the copper plates constituting the vehicle W other than the above. Of course, the present invention is also applicable to spot-weldable portions other than the vehicle W, and in particular, it can be suitably applied to joining portions of thin metal portions that need to be approached from the inside of the bag structure.

1 spot welding device
10 articulated robot
11-16 links
20 spot welding gun
21 welding body
22 Pressurization
23a, 23b electrode
24 Pressurized Motor
25 Ball Screw
26 Nut part
27 bolts
29, 43 belt
30 rotating mechanism
31 attachment
32 1st bearing part
33, 34 Casing (Pressure Part)
35 trance
36 Rotary Motor
37 Rotary Transmission
38 Casing (Rotating Mechanism)
39 input section
40 reducer
40a rotating part
40b fixing part
41 Output
44 connections
45 2nd bearing part
W vehicle
Wa sidemember
Wb loop member
Wc1, Wc2 welding area
Window frame of a Wd vehicle
We interior space
X1 ~ X6 rotation axis (articulated robot)
X7 rotary shaft (rotary mechanism)
X8 rotary shaft (pressurized motor)
Y1 compression shaft (rotary motor)
θ1 ~ θ5 joint angle

Claims (3)

A multi-joint robot having a plurality of links and joints and a spot welding gun mounted to a tip link positioned at a tip of the multi-joint robot among the plurality of links,
A blocking link is connected to the proximal end of the leading link so that the leading link rotates about a predetermined first rotation axis without changing the attitude with respect to the blocking link.
The spot welding gun is a spot welding device mounted on the tip link in a posture where the pressure axis of the spot welding gun and the first rotary shaft intersect,
And a rotating mechanism for rotating the spot welding gun around a second rotational axis intersecting the first rotational axis without changing the attitude of the spot welding gun relative to the tip link.
Spot welding device. The method of claim 1
The rotating mechanism has a casing and the casing rotates around the second axis of rotation with the spot welding gun;
Spot welding device. The method according to claim 1 or 2,
The rotating mechanism has a rotary driving unit for generating a rotary driving force and a rotary transmission mechanism for transmitting the rotary driving force generated in the rotary driving unit to the spot welding gun,
The rotation transmission mechanism is disposed between the spot welding gun and the tip link, and the rotation driving unit and the rotation transmission mechanism are disposed in parallel,
Spot welding device.

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