JP7185891B2 - projection welding equipment - Google Patents

Description

The present invention belongs to the technical field related to projection welding equipment.

2. Description of the Related Art Conventionally, when a weld nut is provided on a vehicle body component of an automobile, the weld nut is formed by joining the projection nut to the vehicle body component as a work by projection joining.

For example, Patent Document 1 discloses a resistance welder (projection welding device) that includes an upper electrode and a lower electrode, and welds a steel plate and a projection nut between the upper and lower electrodes. The electrode holder has a vertically movable guide pin that positions the steel plate and the projection nut, and a push-up member that is connected to the guide pin via a rod and always urges the guide pin upward. Disclosed is a resistance welder with a built-in.

Further, in the resistance welder described in Patent Document 1, the guide pin has a rod portion and a nut receiving portion for receiving a projection nut. The nut receiving part consists of a projection with a semi-elliptical cross section. When the guide pin guides the projection nut to the welding position, the nut receiving part penetrates the hole of the workpiece up to the rod part of the guide pin. It is designed to receive a projection nut.

Japanese Patent No. 6069647

By the way, a projection nut having a different inner diameter for each purpose is usually used as the weld nut. Therefore, it may be necessary to join a plurality of types of projection nuts having different inner diameters to one vehicle body component. In this case, the diameter of the hole in the work to which the projection nut is joined is also changed according to the inner diameter of the projection nut.

In the projection welding device described in Patent Document 1, when the projection nut is guided to the welding position by the guide pin, the nut receiving portion receives the projection nut while the rod portion of the guide pin penetrates the hole portion of the workpiece. Therefore, it cannot be applied when the diameter of the hole of the work is smaller than the diameter of the rod of the guide pin. In other words, one guide pin can only guide a projection nut with a specific inner diameter. Therefore, when joining projection nuts with different inner diameters, it is necessary to replace the guide pin or prepare multiple projection welding devices for each inner diameter of the projection nut, which may lead to a deterioration in productivity. .

The present invention has been made in view of such a point, and its object is to improve productivity by making it possible to join projection nuts with various inner diameters with a single projection welding device. .

In order to solve the above-mentioned problems, in the first invention, the workpiece and the projection nut are sandwiched between an upper electrode and a lower electrode provided in a welding device main body, and the workpiece is welded by projection welding by energization. a cylindrical electrode holder provided on the lower electrode, and a cylindrical electrode holder provided in the cylinder of the lower electrode holder for positioning the workpiece and the projection nut. The guide pin includes a rod portion extending in the cylinder axis direction of the lower electrode holder and arranged in the cylinder of the lower electrode holder, and an axis of the rod portion in the rod portion. a nut receiving portion provided at the upper end of the direction and receiving the projection nut, at least the nut receiving portion receiving the projection nut in a state in which at least the nut receiving portion passes through a hole formed in the work; , the nut receiving portion has a stepped shape extending from the upper side to the lower side in the axial direction so as to receive a plurality of types of projection nuts having different inner diameters , and the maximum diameter of the rod portion is The rod portion has a recessed portion which is smaller than the maximum diameter of the lower electrode holder and is recessed radially inwardly of the rod portion, and the guide pin is biased in the radial direction of the lower electrode holder. A claw portion arranged in the cylinder of the lower electrode holder is held by the lower electrode holder by engaging with the recessed portion, and when pulled upward with respect to the lower electrode holder, the claw portion The electrode is pulled out from the lower electrode holder after the engagement between the portion and the recessed portion is released.

In the second invention, the nut receiving portion includes a plurality of cylindrical bodies each having a diameter smaller than the maximum diameter of the rod portion and having different diameters, and the cylindrical bodies having smaller diameters are positioned upward in the axial direction. Each cylindrical body is configured to receive the projection nut having an inner diameter corresponding to the diameter of each cylindrical body.

According to a third invention, in the second invention, an upper ridge portion of each of the cylindrical bodies constituting the nut receiving portion is processed into a rounded shape.

In a fourth invention, in the invention according to any one of the first to third inventions, the welding device joins the projection bolt to the workpiece in addition to the projection nut. In addition to the nut receiving portion, the guide pin further has a bolt receiving portion for receiving the projection bolt, and is configured to be able to position the work and the projection bolt, and The bolt receiving portion is configured by a projection projecting upward in the axial direction from the uppermost end portion of the nut receiving portion.

In a fifth aspect according to the fourth aspect , the lower electrode has an electrode tip that is provided at an upper end portion of the lower electrode holder in the cylinder axis direction and contacts the workpiece during projection welding. , the entire nut receiving portion and the bolt receiving portion of the guide pin pass through the electrode tip and extend above the electrode tip in a no-load state in which no downward force is applied to the guide pin. When joining the projection nut or the projection bolt around the hole of the work having a hole smaller than the maximum diameter of the rod portion of the guide pin, the work and the The electrode tip and the workpiece are brought into contact with each other by pushing down the guide pin together with the projection nut or the projection bolt in the axial direction of the cylinder.

In a sixth aspect according to the fifth aspect, the welding apparatus main body further includes upper electrode lifting means for lifting and lowering the upper electrode, and the upper electrode lifting means moves the upper electrode and the projection nut during projection welding. Alternatively, the upper electrode is moved toward the lower electrode so as to bring the projection nut or the projection bolt into contact with the work while the projection bolt is in contact with the guide. When the projection nut or the projection bolt is joined around the hole of the work having a hole smaller than the maximum diameter of the rod portion of the pin, the upper electrode is moved by the upper electrode elevating means. By moving toward the lower electrode, the guide pin is pushed downward in the axial direction of the cylinder so that the electrode tip and the workpiece are brought into contact with each other.

According to a seventh invention, in the invention according to any one of the first to sixth inventions, the welding device main body is held by an arm of a robot having a displaceable arm. .

According to the first invention, the nut receiving portion has a stepped shape extending from the upper side to the lower side in the axial direction of the rod portion so as to receive a plurality of types of projection nuts having different inner diameters. Each stage of the shape can receive different projection nuts with different inner diameters. As a result, various projection nuts having different inner diameters can be properly guided without replacing the guide pin. Therefore, it is possible to join projection nuts with various inner diameters with a single projection welding apparatus, thereby improving productivity.

Further, since the nut receiving portion has a stepped shape, when the nut receiving portion receives the projection nut, it is possible to prevent the projection nut from being tilted as much as possible. As a result, it is possible to suppress the deviation between the axis of the projection nut and the center of the hole of the work as much as possible.

According to the second invention, when the diameter of the hole in the work is smaller than the diameter of the rod, only the nut receiving portion passes through the hole in the work. Since the nut receiving portion is formed of a cylindrical body, even if only the nut receiving portion passes through the hole of the work, the amount of projection of the nut receiving portion with respect to the work can be increased to some extent. Thereby, even if the diameter of the hole of the work is smaller than the maximum diameter of the rod, the projection nut can be properly guided. In the nut receiving portion, a plurality of cylindrical bodies with different diameters are arranged so that cylindrical bodies with smaller diameters are positioned at the upper side, and each cylindrical body has a projection with an inner diameter corresponding to the diameter of each cylindrical body. Since the nut can be received, various projection nuts with different inner diameters can be appropriately guided without replacing the guide pin. Therefore, it is possible to join projection nuts with various inner diameters with a single projection welding apparatus, thereby further improving productivity.

According to the fourth invention, a single projection welding device can join not only the projection nut but also the projection bolt to the workpiece, thereby further improving productivity.

According to the fifth invention, the entire nut receiving portion and bolt receiving portion of the guide pin penetrate through the electrode tip in a no-load state in which no downward force is applied to the guide pin, and extend beyond the electrode tip. Since it is located on the upper side, it becomes easy to pass the guide pin through the hole of the work, and the alignment of the work becomes easy.

On the other hand, when the diameter of the hole in the work is smaller than the maximum diameter of the rod portion of the guide pin, only the relatively upper cylindrical body among the plurality of cylindrical bodies constituting the nut receiving portion is the hole. pass through the part. Therefore, when the entire nut receiving portion and bolt receiving portion of the guide pin pass through the electrode tip and are positioned above the electrode tip, the nut receiving portion or the bolt receiving portion of the work may be positioned above the electrode tip. A gap is formed between the electrode tip and the work at the stage of penetrating the hole. Therefore, the workpiece and the electrode tip can be brought into contact with each other by pushing down the guide pin in the cylinder axis direction together with the workpiece and the projection nut or projection bolt. Even if the entire nut-receiving portion and bolt-receiving portion of the guide pin pass through the electrode tip and are positioned above the electrode tip, projection welding can be properly performed.

According to the sixth invention, the downward movement of the upper electrode by the upper electrode elevating means can be used to push down the guide pin together with the workpiece and the projection nut or projection bolt downward in the cylinder axis direction. , a separate mechanism for pushing down the workpiece or the like is not required, and the structure of the apparatus main body can be simplified. In addition, when the electrode tip of the lower electrode and the work come into contact with each other, the upper electrode, the projection nut or the projection bolt, the work, and the lower electrode become energized, so that the welding cycle time can be shortened. Productivity can be further improved.

According to the seventh invention, the apparatus body can be moved to position the workpiece and the projection nut or the workpiece and the projection bolt. The above-mentioned positioning at a point becomes easy. Thereby, productivity can be improved further.

1 is a perspective view showing the configuration of a projection welding device according to an embodiment of the present invention; FIG. It is a side view of the upper electrode and lower electrode of a projection welding apparatus. 3 is a sectional view corresponding to line III-III of FIG. 2; FIG. It is an enlarged view of a guide pin. FIG. 4 is a cross-sectional view showing the configuration of a chuck of the bolt supply device; 1 is a schematic diagram showing a control system of a projection welding device; FIG. FIG. 10 is a diagram showing a state in which a work is conveyed when the projection nut is joined to the work; FIG. 8 is a diagram showing a state in which the guide pin is inserted through the hole of the work from the state of FIG. 7; FIG. 9 is a diagram showing a state in which a projection nut is supplied from the state of FIG. 8; FIG. 10 is a diagram showing a state in which the projection nut and the workpiece are sandwiched between the upper electrode and the lower electrode from the state shown in FIG. 9 and energization is started; FIG. 9 is a view equivalent to FIG. 8 when another projection nut is received by the nut receiving portion; FIG. 10 is a diagram showing a state in which the guide pin receives the bolt when the projection bolt is joined to the work; 13 is a diagram showing a state in which the upper electrode pushes the projection bolt downward from the state of FIG. 12; FIG. FIG. 14 is a diagram showing a state in which the projection bolt is in contact with the work from the state shown in FIG. 13; 15 is a diagram showing a state in which the bolt delivery device is retracted from the state of FIG. 14 and energization is started; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. It should be noted that the following description of preferred embodiments is merely exemplary in nature.

<overall structure>
FIG. 1 schematically shows a projection welding device 1 according to an embodiment of the invention. This projection welding device 1 joins a projection nut N (see FIGS. 7 to 11) and a projection bolt B (see FIGS. 5 and 12 to 15) to a work W (see FIG. 7, etc.) by projection welding. This is a projection welding device for

As shown in FIG. 1, the projection welding device 1 supplies a robot 10 having a displaceable arm 11, a welding device body 20, a nut supply device 30 for supplying projection nuts N, and projection bolts B. and a controller 100 (see FIG. 6) that controls the operation of the robot 10, the welding device body 20, the nut supply device 30, and the bolt supply device 40.

The robot 10 is an articulated industrial robot having three arms 11 rotatably connected to each other and a base 12 . The three arms 11 are a base-side arm 11a having a base end connected to the base 12, a body-side arm 11b having a welding device main body 20 held at its tip, and a tip portion of the base-side arm 11a and the main body side. It is composed of an intermediate arm 11c that connects the base end side of the arm 11b. The base 12 is installed on the floor of the factory or the like, so that the projection welding apparatus 1 is fixed to the floor of the factory or the like.

The base-side arm 11a is connected to the base 12 so as to be rotatable about an axis extending in the vertical direction. When the base-side arm 11a rotates around the axis, each arm 11 rotates in the horizontal direction together with the welding apparatus main body 20. As shown in FIG.

A tip portion of the base-side arm 11a and one longitudinal end portion of the intermediate arm 11c, and a base end portion of the body-side arm 11b and the other longitudinal end portion of the intermediate arm 11c are connected to a shaft 13 extending in the horizontal direction. They are connected to each other so as to be rotatable around. The welding device body 20 can be advanced and retracted in a direction perpendicular to both the vertical axis and the axis 13 by rotating the body side arm 11 b and the intermediate arm 11 c about the axis 13 .

In the following description, the direction in which the shaft 13 extends is called the left-right direction, and the direction perpendicular to both the vertical axis and the shaft 13 is called the front-rear direction. As for the front-rear direction, the side where the welding device main body 20 separates from the base 12 is called the front side, and the side where the welding device main body 20 approaches the base 12 is called the rear side.

The welding device body 20 has an upper electrode 50 , an upper cylinder 51 (upper electrode elevating means) for elevating the upper electrode 50 , and a lower electrode 60 .

<Upper electrode>
As shown in FIG. 1, the upper electrode 50 is held at the tip of the body-side arm 11b via a support mechanism together with the upper cylinder 51. As shown in FIG. The support mechanism includes an upper support portion 22 that supports the upper cylinder 51, and a lower support portion 23 that extends downward from the upper support portion 22 and then extends forward in a substantially L-shaped side view. have. A lower holding portion 23a is provided at the tip of the lower support portion 23 to sandwich and hold the lower electrode 60 (strictly speaking, a lower electrode holder 61 to be described later).

The upper electrode 50 is held at the lower end of an upper electrode holder 52, as shown in FIGS. The upper end side portion of the upper electrode holder 52 faces the inside of the upper cylinder 51 . The upper electrode 50 is raised and lowered by raising and lowering the upper electrode holder 52 with the upper cylinder 51 .

The upper cylinder 51 is a fluid pressure cylinder that raises and lowers the upper electrode 50 using hydraulic pressure and air pressure. Although not shown, an urging member is provided in the upper cylinder 51 for urging the upper electrode 50 upward. When the upper cylinder 51 is not supplied with fluid, the upper electrode 50 is moved upward (i.e., raised) by the biasing force of the biasing member, while the upper cylinder 51 is supplied with fluid. The upper electrode 50 is moved downward (that is, lowered) when the fluid pressure generated by the fluid becomes a fluid pressure that generates a force that overcomes the urging force of the urging member. there is

<Lower electrode>
The lower electrode 60 has a lower electrode holder 61 as shown in FIG. The lower electrode holder 61 has a cylindrical shape and extends so that the cylinder axis direction is the vertical direction. A guide pin 80, which will be described later, is inserted through the cylinder of the lower electrode holder 61 so as to be able to move up and down.

The lower electrode 60 has an electrode socket 62 placed on the upper end of the lower electrode holder 61 and an electrode tip 63 fitted to cover the electrode socket 62 from above. Both the electrode socket 62 and the electrode tip 63 have through holes through which the guide pins 80 are inserted. The center of the through hole is positioned on the cylinder axis of the lower electrode holder 61 . The diameter of the through hole is set to the same diameter as the inner diameter of the lower electrode holder 61 .

The lower electrode holder 61 is held by a holder base 64 at its lower end, as shown in FIG. A lower cylinder 65 for raising and lowering the guide pin 80 is provided on the lower portion of the holder base 64 . The lower cylinder 65 is composed of an air cylinder. The lower cylinder 65 is provided with an air supply passage 65 a for supplying air into the lower cylinder 65 .

Further, as shown in FIGS. 2 and 3, a cooling plate for supplying cooling water for cooling the lower electrode 60 at the time of projection welding is provided in a portion near the lower side of the lower electrode holder 61 and above the holder base 64 . A water supply portion 66 and a cooling water discharge portion 67 for discharging the cooling water after cooling the lower electrode 60 are provided. The cooling water supply portion 66 and the discharge portion 67 each extend straight outward in the radial direction of the lower electrode holder 61 and then extend downward in the radial direction at an angle. . Although not shown, the cooling water supply portion 66 and the discharge portion 67 are connected to a hose connected to a cooling water supply device such as a water pump. The cooling water supplied from the cooling water supply device through the cooling water supply section 66 flows through the lower electrode holder 61, cools the lower electrode 60 during projection welding, and then passes through the cooling water discharge section 67. It is adapted to flow into the cooling water supply.

As shown in FIG. 3, in the cylinder of the lower electrode holder 61, a vertically movable guide pin 80 for positioning the work W and the projection nut N, and the work W and the projection bolt B, and the guide pin 80 via a connecting screw 68, and a resin rod 70 whose upper end is connected to the connecting screw 68 and whose lower end is connected to the cylinder rod 65b of the lower cylinder 65. is inserted.

<guide pin>
As shown in FIG. 4, the guide pin 80 is provided at a rod portion 81 extending in the axial direction of the lower electrode holder 61 and at an upper end portion of the rod portion 81 in the axial direction, and is connected to the projection nut. and a bolt receiving portion 83 provided on the upper side of the nut receiving portion 82 and receiving the projection bolt B. As shown in FIG.

As shown in FIGS. 3 and 4, the rod portion 81 of the guide pin 80 has a large diameter portion 81a extending vertically with a diameter slightly smaller than the inner diameter of the lower electrode holder 61, and a large diameter portion 81a extending radially inward from the large diameter portion 81a. an intermediate portion 81c formed with a recessed portion 81b (see FIG. 4 in particular), and a small diameter portion 81d having a diameter larger than the minimum diameter of the intermediate portion 81c and smaller than the large diameter portion 81a and extending in the vertical direction. , and a diameter-reduced portion 81e extending downward from the lower end of the small-diameter portion 81d. As shown in FIGS. 3 and 4, the intermediate portion 81c is formed below the large diameter portion 81a, and the small diameter portion 81d is formed below the intermediate portion 81c. A lower end portion of the reduced diameter portion 81 e is placed on the connecting screw 68 . The large-diameter portion 81a, the intermediate portion 81c, the small-diameter portion 81d, and the reduced-diameter portion 81e of the rod portion 81 are formed coaxially.

The nut receiving portion 82 of the guide pin 80 has a stepped shape from the top to the bottom in the axial direction of the rod portion 81 so as to be able to receive a plurality of types of projection nuts N having different inner diameters. Specifically, as shown in FIGS. 3 and 4, the nut receiving portion 82 includes a plurality of cylindrical bodies each having a smaller diameter than the maximum diameter of the rod portion 81 and having different diameters. They are arranged so that cylindrical bodies with smaller diameters are located on the upper side. More specifically, as shown in FIGS. 3 and 4, the nut receiving portion 82 includes a first nut receiving portion 82a formed of a cylindrical body having a smaller diameter than the large diameter portion 81a of the rod portion 81; A second nut receiving portion 82b formed of a cylindrical body having a diameter smaller than that of the first nut receiving portion 82a is provided so that the second nut receiving portion 82b is positioned above the first nut receiving portion 82a. configured. More specifically, the first nut receiving portion 82a extends upward in the axial direction of the rod portion 81 from the upper end of the large diameter portion 81a of the rod portion 81. From the upper end of the first nut receiving portion 82a, The second nut receiving portion 82b extends upward in the axial direction.

Both the first nut receiving portion 82 a and the second nut receiving portion 82 b are formed coaxially with the rod portion 81 . That is, the rod portion 81, the first nut receiving portion 82a, and the second nut receiving portion 82b are coaxial.

The diameter of the first nut receiving portion 82a and the diameter of the second nut receiving portion 82b are set according to the inner diameter of the projection nut N joined to the workpiece W. As shown in FIG. For example, if the projection nut N to be joined to the workpiece W includes a nut having an inner diameter of about 7 mm and a nut having an inner diameter of about 5 mm, the diameter of the first nut receiving portion 82a is smaller than 7 mm (for example, 6.8 mm). while the diameter of the second nut receiving portion 82b is set to be smaller than 5 mm (for example, 4.8 mm).

The height of the first nut receiving portion 82a and the height of the second nut receiving portion 82b are set according to the height of the projection nut N joined to the workpiece W. As shown in FIG.

As shown in FIGS. 3 and 4, the bolt receiving portion 83 protrudes upward in the axial direction of the rod portion 81 from the uppermost cylindrical body among the plurality of cylindrical bodies forming the nut receiving portion 82. Consists of projections. More specifically, the bolt receiving portion 83 is formed of a cone-shaped or truncated cone-shaped projection that protrudes upward in the axial direction from the radial center of the second nut receiving portion 82b.

The maximum diameter of the cone or truncated cone that constitutes the bolt receiving portion 83 (the diameter of the joint portion with the second nut receiving portion 82b) is, as shown in FIGS. 3 and 4, larger than the diameter of the second nut receiving portion 82b. small.

The bolt receiving portion 83 is coaxial with the nut receiving portion 82 . Therefore, the rod portion 81, the nut receiving portion 82 (the first nut receiving portion 82a and the second nut receiving portion 82b), and the bolt receiving portion 83 are coaxial.

The guide pin 80 is placed on the tie screw 68 while being axially and radially held by the pawl member 69, as shown in FIG. The claw member 69 is composed of four claws in this embodiment. The claw member 69 includes a screw side engaging portion 69a engaged with the connecting screw 68, four claw portions 69b respectively engaged with the recessed portion 81b of the guide pin 80, a screw side engaging portion 69a and each claw portion 69b. It has a connection portion 69c that connects the . The screw-side engaging portion 69a has a cylindrical shape that covers a portion of the connecting screw 68 in the axial direction in the circumferential direction. The four connecting portions 69c are arranged at equal intervals in the circumferential direction of the screw-side engaging portion 69a, so that the four claw portions 69b are also arranged at equal intervals in the circumferential direction.

The connecting portions 69c of the claw members 69 are respectively made of an elastic member, and when the claw portions 69b are engaged with the recessed portions 81b of the guide pins 80, the connecting portions 69c are elastically moved to the respective claw portions 69b. is pressed radially inward of the guide pin 80 against the recessed portion 81b. As a result, the guide pin 80 is held axially and radially. That is, the guide pin 80 is held in the axial and radial directions by the elastic force of the connecting portion 69c of the claw member 69. As shown in FIG.

As described above, the pawl members 69 hold the guide pins 80 by pressing the pawl portions 69b radially inwardly of the guide pins 80 against the recessed portions 81b. of the guide pin 80, the holding force in the axial direction is weaker than the holding force in the radial direction. Therefore, when the guide pin 80 is pulled upward with respect to the lower electrode holder 61 , the guide pin 80 is extracted from the lower electrode holder 61 . This allows the guide pin 80 to be removed from the lower electrode holder 61 when it becomes necessary to replace the guide pin 80 . Further, since the reduced diameter portion 81 e is formed at the lower end portion of the rod portion 81 of the guide pin 80 , the guide pin 80 can be easily attached to the lower electrode holder 61 . Therefore, the guide pin 80 can be easily replaced.

As shown in FIG. 3 , the claw member 69 is fitted inside the cylinder of the lower electrode holder 61 in the radial direction of the lower electrode holder 61 . When the guide pin 80 is moved up and down by the lower cylinder 65 , the claw member 69 is also moved up and down through the cylinder of the lower electrode holder 61 and the through hole of the electrode socket 62 .

As described above, the resin rod 70 has the connecting screw 68 fastened to its upper end. As a result, the resin rod 70 holds the guide pin 80 via the connecting screw 68 and the pawl member 69 .

Also, as described above, the lower end of the resin rod 70 is connected to the cylinder rod 65b. When air is supplied to the lower cylinder 65 and the cylinder rod 65b rises, the resin rod 70 also rises together with the cylinder rod 65b. As the resin rod 70 rises, the guide pin 80 held by the resin rod 70 rises. On the other hand, when air is discharged from the lower cylinder 65 and the cylinder rod 65b descends, the resin rod 70 also descends, and the guide pin 80 descends together with the resin rod 70. As shown in FIG.

As shown in FIG. 3, the lower end of the resin rod 70 floats above the bottom of the holder base 64 in a no-load state in which no downward force is applied to the guide pin 80 . Specifically, in this embodiment, a constant amount of air is always supplied to the lower cylinder 65, and the force based on this constant amount of air causes the cylinder rod 65b and the resin rod 70 to move upward. , and the resin rod 70 is lifted from the bottom of the holder base 64 . As a result, in a no-load state in which no downward force is applied to the guide pin 80, as shown in FIG. , passes through the electrode tip 63 and is positioned above the electrode tip 63 .

A position sensor 101 (see FIG. 6) for detecting the position of the resin rod 70 is provided on the lower cylinder 65 .

<Nut supply device>
The nut supply device 30 includes a nut shooter 31 and a nut guide device 32, as shown in FIG. The nut shooter 31 has a nut supply portion 33 and a nut standby portion 34 . The nut supply unit 33 is connected to a nut supply source (not shown) by a connector such as a tube. The nut guide device 32 has a guide cylinder 35, a nut supply rod (not shown) inserted into the guide cylinder 35, and an air cylinder (not shown) for driving the nut supply rod to advance and retreat. there is

The projection nut N sent from the nut supply source through the nut supply section 33 waits in the nut standby section 34 . When the air cylinder is driven while the projection nut N is waiting in the nut waiting portion 34, the nut supply rod holds the projection nut N waiting in the nut waiting portion 34 and moves the projection nut N to the guide pin 80. moving forward. After that, the projection nut N is received by the nut receiving portion 82 of the guide pin 80 . In this manner, the projection nut N is supplied from the nut supply device 30 to the position of the guide pin 80 .

As shown in FIGS. 9 and 11, the projection nut N is preformed with a welded portion N1 to be welded to the work W, and the welded portion N1 of the projection nut N is positioned on the work W side. As such, it is supplied to the position of the guide pin 80 .

In this embodiment, as shown in FIG. 1, two nut supply devices 30 are provided. These two nut supply devices 30 supply projection nuts N with different inner diameters. The two nut supply devices 30 themselves have the same configuration. If the above nut supply source is capable of sorting projection nuts and supplying projection nuts with a desired inner diameter from a plurality of projection nuts with different inner diameters, the nut supply device 30 can be used in one unit. may

<Bolt supply device>
The bolt supply device 40 includes a bolt shooter 41 and a bolt guide device 42, as shown in FIG. The bolt shooter 41 is connected to a bolt supply source (not shown) by a connector such as a tube. The bolt guide device 42 includes a chuck 43 for holding the projection bolt B, a guide cylinder 44 in which a rod 44a for guiding the chuck 43 to the position of the guide pin 80 is inserted, and an air for driving the rod 44a to move back and forth. and a cylinder (not shown).

The chuck 43 is configured such that a pair of chuck levers 43a can be horizontally moved toward and away from each other. Although not shown in detail, the chuck levers 43a are biased toward each other by a spring, and in a no-load state in which no load is applied to the chuck levers 43a, they are in contact with each other in the horizontal direction. It's becoming On the other hand, when a force is applied to the chuck levers 43a in a direction in which the chuck levers 43a move away from each other, the chuck levers 43a move in a direction away from each other.

As shown in FIG. 5, a cup-shaped bolt holding portion 45 is formed on the tip side (the side opposite to the rod 44a) of the chuck 43. As shown in FIG. The bolt holding portion 45 has a through-hole 46 formed by a pair of chuck levers 43a cooperatively passing therethrough in the vertical direction. As shown in FIG. 5, the portion of the bolt holding portion 45 that constitutes the through hole 46 includes a tapered portion 45a that is tapered so as to decrease in diameter downward, and a tapered portion 45a that extends vertically from the lower end of the tapered portion 45a. It has a straight portion 45b extending with a uniform diameter, and an inner protruding portion 45c provided at the lower end of the straight portion 45b and protruding inward from the straight portion 45b. A surface forming the through-hole 46 of the inner projecting portion 45c is a tapered surface 46a inclined downward.

In this embodiment, as shown in FIG. 5, the tip of the projection bolt B is received by the inner projecting portion 45c. In the state in which the projection bolt B is held, the tip of the projection bolt B is located at the position of the inner projecting portion 45c in the bolt holding portion 45. As shown in FIG.

In the bolt supply device 40, after the projection bolt B supplied from the bolt shooter 41 is held by the bolt holding portion 45 of the chuck 43, the air cylinder is driven and the rod advances toward the guide pin 80. . After that, the projection bolt B is received by the bolt receiving portion 83 of the guide pin 80 while being held by the chuck 43 . As described above, in the present embodiment, the tip of the projection bolt B is positioned at the height of the inner projecting portion 45c. Therefore, even if the axial length of the projection bolt B is different, There is no need to change the advancing angle of the rod. Therefore, the configuration and control of the bolt supply device 40 for supplying the projection bolt B to the position of the guide pin 80 can be simplified.

The projection bolt B is formed with an engaging recess B1 recessed toward the head side at the tip thereof, and as shown in FIGS. The projection bolt B is received by engaging with the engagement recess B1 of B. Further, as shown in FIGS. 12 to 15, the projection bolt B is preliminarily formed with a welding portion B2 to be welded to the workpiece W, and the projection bolt B is held by the bolt holding portion 45. Then, the welded portion B2 is positioned on the work W side. Although the details will be described later, the projection bolt B is pushed downward by the upper electrode 50 after being received by the bolt receiving portion 83, and is moved downward into the hole H of the work W. pass through. As a result, the workpiece W and the welded portion B2 of the projection bolt B are brought into contact with each other.

<Control system>
The control device 100 outputs an actuation signal to the robot 10 to move the welding device body 20 to the welding location of the workpiece W, as shown in FIG.

The control device 100 outputs an actuation signal to the nut supply device 30 to drive the air cylinder of the nut guide device 32 to supply the projection nut N to the position of the guide pin 80 .

The control device 100 outputs an actuation signal to the bolt supply device 40 , supplies the projection bolt B from the bolt supply source to the bolt shooter 41 , and feeds the projection bolt B from the bolt shooter 41 to the bolt holding portion 45 of the chuck 43 . supply. The control device 100 outputs an actuation signal to the bolt supply device 40 to drive the air cylinder of the bolt guide device 42 while the projection bolt B is held by the bolt holding portion 45 to move the projection bolt B to the guide pin. Feed 80 positions.

The control device 100 outputs an actuation signal to the upper cylinder 51 to move the upper electrode 50 up and down. In addition, the control device 100 outputs an actuation signal to the upper electrode 50 and the lower electrode 60 to energize the upper electrode 50 and the lower electrode 60 .

The control device 100 calculates the lifting amount of the resin rod 70 from the detection result of the position sensor 101 . Based on the lift amount of the resin rod 70 calculated from the position sensor 101, the control device 100 determines whether the currently supplied projection nut N or projection bolt B is of the desired standard.

<Joining the projection nut>
Next, the operation of joining the projection nut N to the work W by the projection welding device 1 will be described.

First, the case of joining the projection nut N to the work W will be described. In the following description, the diameter of the hole H formed in the work W is smaller than the maximum diameter of the rod portion 81 of the guide pin 80 (the diameter of the large diameter portion 81a of the rod portion 81) and the first nut receiving portion. A case where the inner diameter of the projection nut N is larger than the diameter of the projection nut N is smaller than the diameter of the first nut receiving portion 82a and larger than the diameter of the second nut receiving portion 82b will be described. The work W is made of, for example, a steel plate, and is carried by a work carrying device (not shown).

First, the work W is conveyed and placed above the guide pins 80 as shown in FIG. At this time, the hole H of the work W and the guide pin 80 are roughly aligned. This alignment can be performed by the robot 10 .

Next, the workpiece W is moved toward the lower electrode 60 and the guide pin 80 is inserted through the hole H. As shown in FIG. At this time, as shown in FIG. , the rod portion 81 of the guide pin 80 does not pass through the hole H, and only the nut receiving portion 82 (first and second nut receiving portions 82a, 82b) and the bolt receiving portion 83 of the guide pin 80 pass through the hole. It will be in a state of penetrating the part H. Since the nut receiving portion 82 is composed of a plurality of cylindrical bodies, even if only the nut receiving portion 82 and the bolt receiving portion 83 pass through the hole H, the nut receiving portion 82 does not protrude from the work W. The amount can be increased to some extent. At this time, the portion of the workpiece W around the hole H is placed on the upper end of the rod portion 81 as shown in FIG. Since the portion of the work W around the hole H is placed on the upper end of the rod portion 81, the nut receiving portion 82 of the guide pin 80 pushes the hole H of the work W as shown in FIG. A gap is formed between the electrode tip 63 of the lower electrode 60 and the lower surface of the work W at the stage of penetration.

Next, the nut supply device 30 is operated to supply the projection nut N to the position of the guide pin 80 . At this time, the projection nut N is supplied so that the welding portion N1 faces the work W side. In this example, as shown in FIG. 9, the supplied projection nut N has an inner diameter smaller than the diameter of the first nut receiving portion 82a and larger than the diameter of the second nut receiving portion 82b. It is received by the nut receiving portion 82b. Thus, the guide pin 80 receives the projection nut N with at least the nut receiving portion 82 passing through the hole H formed in the work W. As shown in FIG.

Since the projection nut N is received by the second nut receiving portion 82b in a state in which the hole portion H of the work W is penetrated to the first nut receiving portion 82a, the projection nut N is supplied as shown in FIG. Then, a gap is formed between the upper surface of the work W and the projection nut N (in particular, the welded portion N1 of the projection nut N).

After the projection nut N is supplied to the position of the guide pin 80, the upper cylinder 51 is driven to move (lower) the upper electrode 50 downward. The upper electrode 50 is moved further downward even after coming into contact with the upper surface of the supplied projection nut N. As a result, the guide pin 80 is pushed downward in the cylindrical axis direction of the lower electrode holder 61 together with the workpiece W and the projection nut N.

The upper cylinder 51 moves the upper electrode 50 toward the lower electrode 60, and the guide pin 80 is pushed downward in the axial direction of the lower electrode holder 61 together with the workpiece W and the projection nut N. 2, the electrode tip 63 of the lower electrode 60 and the lower surface of the workpiece W come into contact with each other.

The upper cylinder 51 moves the upper electrode 50 downward even after the lower surface of the work W contacts the electrode tip 63 of the lower electrode 60 . The electrode tip 63 of the lower electrode 60 is placed on the lower electrode holder 61, and since the lower electrode holder 61 is supported by the support portion 21 of the welding device main body 20, the work W does not move downward. It is supported by the lower electrode 60 as follows. Therefore, after the lower surface of the work W and the electrode tip 63 of the lower electrode 60 are brought into contact with each other, the guide pin 80 and the projection nut N move downward due to the downward movement of the upper electrode 50. do. As a result, the projection nut N (in particular, the welded portion N1 of the projection nut N) comes into contact with the upper surface of the workpiece W. As shown in FIG. Therefore, during projection welding, the upper cylinder 51 moves the upper electrode 50 to the lower electrode 60 so that the projection nut N contacts the workpiece W while the upper electrode 50 and the projection nut N are in contact with each other. configured to move toward

The upper cylinder 51 attempts to move the upper electrode 50 further downward even after the projection nut N contacts the upper surface of the work W. As shown in FIG. The projection nut N is pressed toward the workpiece W by the movement of the upper electrode 50 toward the lower side. The electrode tip 63 of the lower electrode 60 is mounted on the lower electrode holder 61, and the lower electrode holder 61 is supported by the support portion 21 of the welding apparatus main body 20, so that the workpiece W is prevented from moving downward. and receive pressure from the upper electrode 50 . The lower electrode 60 presses the workpiece W toward the projection nut N with a reaction force against the pressure from the upper electrode 50 . As a result, the workpiece W and the projection nut N are clamped between the upper electrode 50 and the lower electrode 60 under pressure.

Electricity is supplied between the upper electrode 50 and the lower electrode 60 while the workpiece W and the projection nut N are sandwiched between the upper electrode 50 and the lower electrode 60 (pressed and sandwiched). , a joining current for projection welding is applied between the upper electrode 50 and the lower electrode 60 . Pressurization of the projection nut N by the upper electrode 50 is continued even while the joining current is flowing. Due to this joining current and the pressure, the contact portion between the upper surface of the work W and the welded portion N1 of the projection nut N is softened, and the welded portion N1 is crushed in the direction of pressure (that is, downward). . At this time, plastic flow occurs between the upper surface of the work W and the welded portion N1 of the projection nut N, and rapid diffusion bonding is performed. Thereby, the projection nut N is joined to the workpiece W. As shown in FIG.

As described above, the work W and the projection nut N are joined by projection welding.

FIG. 11 shows a state in which a guide pin 80 receives a projection nut N having an inner diameter different from that of the projection nut N described above. Specifically, the diameter of the hole H formed in the work W is larger than the maximum diameter of the rod portion 81 of the guide pin 80 (the diameter of the large diameter portion 81a of the rod portion 81), and the inner diameter of the projection nut N is smaller than the maximum diameter of the rod portion 81 of the guide pin 80 and larger than the diameter of the first nut receiving portion 82a.

As shown in FIG. 11, since the diameter of the hole H formed in the work W is larger than the maximum diameter of the rod portion 81 of the guide pin 80, the rod portion 81 of the guide pin 80 also passes through the hole H. It becomes a penetrating state. As a result, the workpiece W comes into contact with the electrode tip 63 of the lower electrode 60 without lowering the guide pin 80 . Here, since the projection nut N has an inner diameter smaller than the maximum diameter of the rod portion 81 and larger than the diameter of the first nut receiving portion 82a, it is received by the first nut receiving portion 82a. In this manner, the first and second nut receiving portions 82a and 82b are configured to be able to receive the projection nuts N having inner diameters corresponding to the diameters of the respective cylindrical bodies that constitute them. When the inner diameter of the projection nut N is larger than the maximum diameter of the rod portion 81 of the guide pin 80, the portion of the rod portion 81 protruding from the hole H of the workpiece W (the tip portion of the large diameter portion 81a) The projection nut N will be received.

The operation of the upper electrode 50 and the lower electrode 60 when welding the projection nut N to the work W from the state of FIG. Since it is the same as described above except that it is

<Joining projection bolts>
Next, the case of joining the projection bolt B to the work W will be described. In the following description, when the diameter of the shaft portion of the projection bolt B is smaller than the diameter of the first nut receiving portion 82a of the guide pin 80 and larger than the diameter of the second nut receiving portion 82b, that is, the hole H of the workpiece W is smaller than the diameter of the first nut receiving portion 82a of the guide pin 80 and larger than the diameter of the second nut receiving portion 82b. The work W is made of, for example, a steel plate, and is transported by the work transport device. The process of inserting the guide pin 80 into the hole H of the work W is the same as the process of joining the projection nut N to the work W, so detailed description thereof will be omitted.

First, the work W is conveyed, placed above the guide pins 80, and the holes H of the work W and the guide pins 80 are roughly aligned. Next, the workpiece W is moved toward the lower electrode 60 and the guide pin 80 is inserted through the hole H. As shown in FIG. At this time, since the diameter of the hole H formed in the work W is smaller than the diameter of the first nut receiving portion 82a of the guide pin 80 and larger than the diameter of the second nut receiving portion 82b, as shown in FIG. Thus, the first nut receiving portion 82a of the guide pin 80 does not pass through the hole H, and only the second nut receiving portion 82b and the bolt receiving portion 83 of the guide pin 80 pass through the hole H. becomes. A portion of the work W around the hole H is placed on the upper end of the first nut receiving portion 82a. Since the portion of the work W around the hole H is placed on the upper end of the first nut receiving portion 82a, the bolt receiving portion 83 of the guide pin 80 is positioned in the hole of the work W as shown in FIG. A gap is formed between the electrode tip 63 of the lower electrode 60 and the lower surface of the work W at the stage where the portion H is penetrated.

Next, the bolt supply device 40 is operated to supply the projection bolt B to the position of the guide pin 80 . The projection bolt B is supplied while being held by the bolt holding portion 45 of the chuck 43, as shown in FIG. The bolt receiving portion 83 of the guide pin 80 engages with the engaging recess of the projection bolt B to receive the projection bolt B. As shown in FIG.

After the projection bolt B is supplied to the position of the guide pin 80, the upper cylinder 51 is driven to move (lower) the upper electrode 50 downward. As shown in FIG. 13, the upper electrode 50 is moved further downward even after coming into contact with the head of the projection bolt B supplied. As a result, the guide pin 80 is pushed downward along the cylindrical axis of the lower electrode holder 61 together with the workpiece W and the projection bolt B. As shown in FIG.

Specifically, when the upper cylinder 51 moves the upper electrode 50 toward the lower electrode 60, the tip of the projection bolt B presses the tapered surface 46a of the inner projecting portion 45c. The pressing force that presses the tapered surface 46a is converted into a horizontal force by the tapered surface 46a, and the pair of chuck levers 43a of the chuck 43 are slightly separated by this converted horizontal force. Thereby, the projection bolt B is moved downward. The workpiece W moves downward together with the guide pin 80 as the guide pin 80 is pushed downward in the axial direction of the lower electrode holder 61 .

After that, when the head of the projection bolt B comes into contact with the tapered portion 45a of the bolt holding portion 45, the head presses the tapered portion 45a. The pressing force pressing the tapered portion 45a is converted into a horizontal force by the tapered portion 45a, and the horizontal force thus converted displaces the pair of chuck levers 43a of the chuck 43 away from each other. This allows the upper electrode 50 to move further downward as shown in FIG. Then, the shaft portion of the projection bolt B is inserted through the hole H of the work W, and the projection bolt B (in particular, the welded portion B2 of the projection bolt B) comes into contact with the upper surface of the work W. For these reasons, the upper cylinder 51 moves the upper electrode 50 to the lower electrode 60 so as to bring the projection bolt B into contact with the workpiece W while the upper electrode 50 and the projection bolt B are in contact with each other during projection welding. configured to move toward

After the projection bolt B abuts against the upper surface of the work W, the chuck 43 is retracted as shown in FIG.

The upper cylinder 51 tries to move the upper electrode 50 further downward even after the projection bolt B contacts the upper surface of the work W and the chuck 43 is retracted. The projection bolt B is pressurized toward the workpiece W by the movement of the upper electrode 50 toward the lower side. The electrode tip 63 of the lower electrode 60 is mounted on the lower electrode holder 61, and the lower electrode holder 61 is supported by the support portion 21 of the welding apparatus main body 20, so that the workpiece W is prevented from moving downward. and receive pressure from the upper electrode 50 . The lower electrode 60 presses the workpiece W toward the projection bolt B with a reaction force against the pressure from the upper electrode 50 . As a result, the workpiece W and the projection bolt B are clamped between the upper electrode 50 and the lower electrode 60 under pressure.

Electricity is supplied between the upper electrode 50 and the lower electrode 60 while the workpiece W and the projection bolt B are sandwiched between the upper electrode 50 and the lower electrode 60 (pressed and sandwiched). , a joining current for projection welding is applied between the upper electrode 50 and the lower electrode 60 . Pressurization of the projection bolt B by the upper electrode 50 is continued even while the joining current is flowing. Due to this joining current and the pressure, the contact portion between the upper surface of the work W and the welded portion B2 of the projection bolt B is softened, and the welded portion B2 is crushed in the direction of pressure (that is, downward). . At this time, plastic flow occurs between the upper surface of the work W and the welded portion B2 of the projection bolt B, and rapid diffusion bonding is performed. Thereby, the projection bolt B is joined to the work W. As shown in FIG.

As described above, the workpiece W and the projection bolt B are joined by projection welding.

As described above, according to the present embodiment, the nut receiving portion 82 of the guide pin 80 has a stepped shape from the upper side to the lower side in the axial direction so as to be able to receive a plurality of types of projection nuts N having different inner diameters. , each step of the stepped shape can receive various projection nuts having different inner diameters. As a result, projection nuts N having different inner diameters can be properly guided without exchanging the guide pin 80 . Therefore, projection nuts N with various inner diameters can be joined by one projection welding apparatus 1, and productivity can be improved.

In particular, in this embodiment, since the nut receiving portion 82 of the guide pin 80 is formed of a cylindrical body, even if only the nut receiving portion 82 passes through the hole H of the work W, the nut receiving portion 82 does not move toward the work W. can be increased to some extent. Accordingly, even if the diameter of the hole H of the work W is smaller than the diameter of the rod portion 81 of the guide pin 80, the projection nut N can be properly guided. In addition, the nut receiving portion 82 has a plurality of cylindrical bodies each having a different diameter, and the cylindrical bodies having smaller diameters are arranged toward the upper side. Since the projection nut N having the inner diameter can be received, the projection nut N having a different inner diameter can be properly guided without exchanging the guide pin 80 . Therefore, projection nuts N with various inner diameters can be joined by one projection welding apparatus 1, and productivity can be further improved.

Further, according to the guide pin 80 of this embodiment, when the projection nut N is received by the nut receiving portion 82, the projection nut N can be prevented from being tilted as much as possible. As a result, it is possible to suppress the deviation between the axis of the projection nut N and the center of the hole H of the work W as much as possible.

Further, according to the present embodiment, the projection bolt B can be joined to the workpiece W in addition to the projection nut N with a single projection welding device 1, so productivity can be further improved. Further, the bolt receiving portion 83 of the guide pin 80 extends from the uppermost cylindrical body (in this embodiment, the second nut receiving portion 82b) among the plurality of cylindrical bodies forming the nut receiving portion 82 to the rod portion 81. Therefore, if the diameter of the hole H of the work W is a diameter that allows a part of the nut receiving portion 82 to pass through, the bolt receiving portion 83 is always formed in the work W. It passes through the hole H. As a result, the projection bolt B can be properly received by the bolt receiving portion 83, and the projection bolt B can be properly guided to the joining position.

Furthermore, in the present embodiment, the entire nut receiving portion 82 and bolt receiving portion 83 of the guide pin 80 pass through the electrode tip 63 in a no-load state in which no downward force is applied to the guide pin 80, Since the guide pin 80 is positioned above the electrode tip 63, it is easy to pass the guide pin 80 through the hole H of the work W, and the alignment of the work W becomes easy.

Here, when the diameter of the hole H of the work W is smaller than the diameter of the rod portion 81 of the guide pin 80, as described above, one of the plurality of cylindrical bodies forming the nut receiving portion 82 has a relatively upper portion. Only the cylindrical body located at the hole H penetrates. Therefore, when the entire nut receiving portion 82 and bolt receiving portion 83 of the guide pin 80 pass through the electrode tip 63 of the lower electrode 60 and are positioned above the electrode tip 63, the nut receiving portion A gap is formed between the electrode tip 63 and the work W when the portion 82 or the bolt receiving portion 83 penetrates the hole H of the work W. As shown in FIG.

On the other hand, in the present embodiment, the projection nut N or the projection bolt B is joined around the hole H of the work W having the hole H smaller than the maximum diameter of the rod portion 81 of the guide pin 80. When the work W and the projection nut N or the projection bolt B are together, the guide pin 80 is pushed downward in the cylinder axis direction of the lower electrode holder 61 to bring the work W and the electrode tip 63 into contact with each other. As a result, even if the entire nut receiving portion 82 and bolt receiving portion 83 of the guide pin 80 pass through the electrode tip 63 and are positioned above the electrode tip 63, projection welding can be properly performed. can be done.

In particular, in the present embodiment, the downward movement of the upper electrode 50 by the upper cylinder 51 is used to move the guide pin 80 along with the work W and the projection nut N or the projection bolt B in the axial direction of the lower electrode holder 61 . Since it is pushed downward, a separate mechanism for pushing down the work W or the like is not required, and the configuration of the welding device main body 20 can be simplified. Further, when the electrode tip 63 of the lower electrode 60 and the work W come into contact with each other, the upper electrode 50, the projection nut N or the projection bolt B, the work W, and the lower electrode 60 become energized. Time can be shortened, and productivity can be further improved.

(Other embodiments)
The present invention is not limited to the above embodiments, and substitutions are possible without departing from the scope of the claims.

For example, in the above-described embodiment, the upper cylinder 51 constitutes the upper electrode elevating means for elevating the upper electrode 50, and pressurizing means for pressurizing the projection nut N and the bolt B toward the work W by the upper electrode 50. However, the configuration is not limited to this, and the upper electrode elevating means and the pressing means may be configured differently. However, even in this case, the upper electrode lifting means moves the projection nut N or the projection bolt B to the workpiece while the upper electrode 50 and the projection nut N or the projection bolt B are in contact with each other during projection welding. It must be configured to move the top electrode 50 toward the bottom electrode 60 to abut W.

Furthermore, in the above-described embodiment, one projection welding device 1 joins the projection nut N or the projection bolt B to one of the holes H formed in the work W, but the projection welding device 1 There may be multiple units. At this time, when a plurality of holes H are formed in the workpiece W, a plurality of projection welding apparatuses 1 can simultaneously perform projection welding on the holes H of a plurality of load locations.

Further, in the above-described embodiment, the welding device main body 20 is held by the robot 10, but may be fixed to the floor surface of the factory or the like instead of being held by the robot 10. FIG. That is, the projection welding device 1 may be a stationary welding device.

The above-described embodiments are merely examples, and should not be construed as limiting the scope of the present invention. The scope of the present invention is defined by the scope of claims, and all variations and modifications within the equivalent scope of the claims are within the scope of the invention.

INDUSTRIAL APPLICABILITY The present invention is suitable for, for example, a projection welding apparatus for providing a weld nut to a body component of an automobile in an automobile manufacturing line.

1 projection welding device 10 robot 11 arm 20 welding device body 50 upper electrode 51 upper cylinder (upper electrode lifting means)
60 lower electrode 61 lower electrode holder 63 electrode tip 80 guide pin 81 rod portion 82 nut receiving portion 82a first nut receiving portion (cylindrical body constituting the nut receiving portion)
82b Second nut receiving portion (the uppermost cylindrical body among the plurality of cylindrical bodies forming the nut receiving portion)
83 Bolt receiving portion B Projection bolt H Hole (workpiece hole)
N Projection nut W Work

Claims (7)

A projection welding device that joins the work and the projection nut by projection welding by energization in a state where the work and the projection nut are sandwiched between an upper electrode and a lower electrode provided in a welding device body. ,
a cylindrical lower electrode holder that holds the lower electrode;
a guide pin provided in the cylinder of the lower electrode holder and capable of moving up and down for positioning the workpiece and the projection nut;
The guide pin is provided at a rod portion extending in the cylinder axis direction of the lower electrode holder and arranged in the cylinder of the lower electrode holder, and at an upper end portion of the rod portion in the axial direction, and a nut receiving portion for receiving the projection nut, wherein at least the nut receiving portion receives the projection nut while passing through a hole formed in the work;
The nut receiving portion has a stepped shape from the upper side to the lower side in the axial direction so as to be able to receive a plurality of types of projection nuts having different inner diameters ,
The maximum diameter of the rod portion is smaller than the inner diameter of the lower electrode holder,
The rod portion has a recessed portion that is recessed radially inward of the rod portion,
The guide pin is biased in the radial direction of the lower electrode holder and is held by the lower electrode holder by engaging a claw portion arranged in the cylinder of the lower electrode holder with the recess portion. 2. A projection welding apparatus, wherein when the lower electrode holder is pulled upward, the claw portion and the recessed portion are disengaged and pulled out from the lower electrode holder. The projection welding device according to claim 1,
In the nut receiving portion, a plurality of cylindrical bodies each having a diameter smaller than the maximum diameter of the rod portion and having different diameters are arranged so that cylindrical bodies with smaller diameters are positioned upward in the axial direction, A projection welding apparatus, wherein each cylindrical body is configured to receive the projection nut having an inner diameter corresponding to the diameter of each cylindrical body. In the projection welding device according to claim 2,
A projection welding apparatus, wherein an upper ridge portion of each of the cylindrical bodies constituting the nut receiving portion is processed into a rounded shape. In the projection welding device according to any one of claims 1 to 3,
The welding device is configured to be able to join the projection bolt to the work in addition to the projection nut,
The guide pin further has a bolt receiving portion for receiving the projection bolt in addition to the nut receiving portion, and is configured to be capable of positioning the work and the projection bolt,
The projection welding device according to claim 1, wherein the bolt receiving portion is constituted by a projection projecting upward in the axial direction from the uppermost end portion of the nut receiving portion. In the projection welding device according to claim 4 ,
The lower electrode has an electrode tip that is provided at the upper end of the lower electrode holder in the cylinder axis direction and contacts the workpiece during projection welding,
The nut receiving portion and the bolt receiving portion of the guide pin as a whole pass through the electrode tip and are positioned above the electrode tip in a no-load state in which no downward force is applied to the guide pin. and
When joining the projection nut or the projection bolt around the hole of the work having the hole smaller than the maximum diameter of the rod portion of the guide pin, the work and the projection nut or the A projection welding apparatus, wherein the electrode tip and the workpiece are brought into contact with each other by pushing down the guide pin together with the projection bolt in the axial direction of the cylinder. In the projection welding device according to claim 5 ,
The welding device main body further includes upper electrode lifting means for lifting and lowering the upper electrode,
The upper electrode elevating means moves the upper electrode so as to bring the projection nut or the projection bolt into contact with the workpiece while the upper electrode and the projection nut or the projection bolt are in contact with each other during projection welding. is configured to move toward the lower electrode,
When joining the projection nut or the projection bolt around the hole of the workpiece having the hole smaller than the maximum diameter of the rod portion of the guide pin, the upper electrode lifting means moves the upper part of the workpiece. A projection welding apparatus, wherein the electrode is moved toward the lower electrode so that the guide pin is pushed downward in the axial direction of the cylinder so that the electrode tip and the workpiece are brought into contact with each other. In the projection welding device according to any one of claims 1 to 6 ,
A projection welding apparatus, wherein the welding apparatus main body is held by an arm of a robot having a displaceable arm.

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