JP2019098386A - Bolt supply device - Google Patents

Abstract

To appropriately supply a projection bolt to a hole part of a work-piece without changing a mode of movement of a chuck holding the projection bolt regardless of a shaft length of the projection bolt.SOLUTION: A bolt supply device 40 comprises: a chuck 43 constituted of a pair of chuck levers 43a that can contact and separate from each other; and a bolt holding part 45, provided in the chuck 43, which receives and holds a projection bolt 90 supplied from a bolt supply source, with the pair of chuck levers 43a contacting each other. The bolt holding part 45 is provided with a tip holding part (an inner protruding part 45c) that can receive a tip part 93 of the projection bolt 90 regardless of a shaft length of the projection bolt 90.SELECTED DRAWING: Figure 7

Description

  The present invention is in the technical field regarding bolt feeding devices.

  Conventionally, for example, in projection welding for joining a projection bolt to a vehicle body component of an automobile, the workpiece is formed by the upper electrode and the lower electrode in a state where the shaft portion of the projection bolt is inserted into a hole formed in the workpiece. Current is supplied between the upper electrode and the lower electrode by sandwiching the projection bolt and the projection bolt. In such projection welding, a bolt supply device is used to supply a projection bolt to the position of the hole of the work.

  For example, in Patent Document 1, a chuck holding a projection bolt is positioned between the upper electrode portion and the work such that the upper electrode, the projection bolt, the hole (welded portion) of the work and the center line of the lower electrode are in a straight line. The bolt supply device is disclosed that moves to the lower part of the upper electrode and presses the projection bolt to lower the chuck to open the chuck and join the workpiece and the projection bolt.

  In the bolt supply device of Patent Document 1, the chuck includes a pair of chuck levers, and a claw which is pivotally supported by the chuck lever so as to be vertically rotatable by a horizontal support pin and always urged in a closing direction by a spring. have. Further, in the bolt supply device of Patent Document 1, a groove is formed at the bottom of the claw at the bottom when a hole through which the bolt of the projection bolt is inserted is formed at the bottom, and the head of the projection bolt is formed by the groove. It is supposed to hold.

JP, 2016-107332, A

  By the way, normally, the projection bolt joined to a workpiece has a different axial length for each purpose. In the bolt supply device as described in Patent Document 1, if the axial length of the projection bolt changes, the amount of projection of the projection bolt from the hole of the chuck changes. That is, the height position of the tip of the projection bolt with respect to the position of the hole of the chuck changes.

  Usually, when the projection bolt is supplied to the position (bonding position) of the hole of the work, the tip of the projection bolt is arranged in the vicinity of the hole. At this time, since the height position of the work is hardly changed, it is necessary to move the chuck in consideration of the height position of the tip when the height position of the tip of the projection bolt with respect to the position of the hole of the chuck changes. There is. For this reason, every time a projection bolt of a different axial length is supplied, it is necessary to change the mode of movement of the chuck, which is troublesome.

  If the vertical distance between the upper electrode and the workpiece is increased in advance, it is not necessary to change the mode of movement of the chuck. However, when joining a relatively short projection bolt to a workpiece, the vertical distance between the workpiece and the tip of the projection bolt is increased. As a result, there is a possibility that the projection bolt can not be properly supplied to the position of the hole of the work.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a projection bolt without changing a movement mode of a chuck for holding the projection bolt regardless of the axial length of the projection bolt. It is an object of the present invention to provide a bolt supply device capable of appropriately supplying the position of the work with the hole portion of the work.

  In order to solve the above problems, in the first invention, in a state where the shaft portion of the projection bolt is inserted into the hole formed in the workpiece, the workpiece and the projection bolt are held between the upper electrode and the lower electrode. In order to join the work and the projection bolt by projection welding by energization, the plurality of types of projections having different axial lengths for a bolt supply device that supplies the projection bolt to the position of the hole of the work A chuck provided with a bolt supply source storing a bolt, a pair of chuck levers that can be separated from each other, and the chuck, and supplied from the bolt supply source in a state in which the pair of chuck levers are in contact with each other A bolt holder for receiving and holding the projection bolt, and A guide device for guiding the projection bolt to the joining position of the work in a state where the projection bolt is held in the part, the chuck includes the projection bolt in the hole portion of the work by the guide device. After being guided to the position, the tip end portion and the shaft portion of the projection bolt are configured to be inserted into the hole portion of the work by separating the pair of chuck levers from each other, and the bolt holding portion A tip holder capable of receiving and holding the tip end of the projection bolt is provided regardless of the axial length of the projection bolt.

  According to a second invention, in the first invention, the bolt holding portion includes a through hole having a circular cross section which is formed by the cooperation of the pair of chuck levers and vertically penetrates, and the bolt holding portion The portion forming the through hole is a tapered portion inclined such that the diameter of the through hole decreases toward the lower side, a straight portion extending with a substantially uniform diameter in the vertical direction from the lower end of the tapered portion, and the straight portion Is provided at the lower end of the projection and has an inner protrusion projecting inward from the straight portion, wherein the tapered portion has a maximum inner diameter larger than a diameter of a head of the projection bolt, while a minimum inner diameter The straight portion is smaller than the diameter of the head of the projection bolt and larger than the diameter of the shaft of the projection bolt, and the straight portion is the projection bolt. And holding the shaft portion, the inner protrusion is characterized by configuring the tip holding portion.

  According to a third invention, in the second invention, the radial inner surface of the through hole in the inner protrusion is a tapered surface which is inclined inwardly in the radial direction toward the lower side. Do.

  A fourth invention is characterized in that, in the second or third invention, the inner protrusion is continuously provided along the circumferential direction of the through hole.

  According to the first aspect of the invention, the bolt holding portion is provided with the tip holding portion capable of receiving and holding the tip end portion of the projection bolt regardless of the axial length of the projection bolt. Instead, the tip end of the projection bolt is held by the tip holder. For this reason, in a state where the projection bolt is held by the bolt holding portion, the tip end portion of the projection bolt is positioned at the height position of the inner projection in the bolt holding portion. As a result, it is not necessary to change the mode of movement of the chuck when moving the chuck in order to arrange the tips of projection bolts of different axial lengths at the positions of the holes. Therefore, the projection bolt can be properly arranged at the position of the hole of the work without changing the movement of the chuck for holding the projection bolt.

  According to the second aspect of the invention, since the shaft portion of the projection bolt is held by the straight portion of the bolt holding portion, the projection bolt can be held stably.

  According to the third aspect of the invention, since the radial inner surface of the through hole in the inner protrusion is a tapered surface which is inclined inwardly in the radial direction toward the lower side, the projection bolt is positioned at the hole portion of the workpiece Operation can be facilitated. That is, for example, after the projection bolt is disposed in the vicinity of the hole of the work, the projection bolt is pressed toward the work side. When the projection bolt is moved to the work side by this pressure, the tip of the projection bolt presses the tapered surface of the inner projection. The pressing force for pressing the tapered surface is converted by the tapered surface into a force in the direction in which the pair of chuck levers are separated. Thus, the pair of chuck levers can be displaced apart from each other. By displacing the pair of chuck levers apart from each other, the inner projections are also separated from each other, so that the projection bolt can be moved toward the hole of the workpiece. Thus, the tip end portion and the shaft portion of the projection bolt can be inserted into the hole of the work. As described above, since the pair of chuck levers can be displaced apart from each other simply by pressing the projection bolt toward the work side, the operation for supplying the projection bolt to the position of the hole of the work is facilitated. Can be Further, since a special device is not required to displace the pair of chuck levers away from each other, enlargement of the chuck can be prevented.

  According to the fourth invention, the tip of the projection bolt can be properly received and held by the inner projection. In particular, as in the third aspect of the invention, if a tapered surface is formed on the inward protruding portion, the force when pressing the projection bolt toward the work side is appropriate for the force in the direction in which the pair of chuck levers separate. It can be converted, and the operation in feeding the projection bolt to the position of the hole of the work can be made easier.

It is a perspective view showing composition of a projection welding device provided with a bolt supply device concerning an embodiment of the present invention. It is a side view of the upper electrode and lower electrode of a projection welding apparatus. FIG. 3 is a cross-sectional view corresponding to line III-III in FIG. 2; It is a perspective view which shows the structure of the chuck | zipper of a bolt supply apparatus. It is the top view which looked at the bolt holding part of a chuck | zipper from the upper side. FIG. 6 is a cross-sectional view corresponding to the VI-VI line of FIG. 5; It is sectional drawing which shows the state which received the projection bolt in which axial length differs by a bolt holding part. It is the schematic which shows the control system of a projection welding apparatus. It is a case where it joins a projection bolt to a workpiece | work, and is a figure which shows the state in which the guide pin was penetrated by the hole of a workpiece | work. It is a figure which shows the state which the guide pin received the volt | bolt from the state of FIG. It is a figure which shows the state which an upper electrode pushes in a projection bolt below from the state of FIG. It is a figure which shows the state which the projection bolt contact | abutted to the workpiece | work from the state of FIG. It is a figure which shows the state which the bolt delivery apparatus retracted | saved from the state of FIG. 12, and started electricity_supply. It is a top view which shows the modification of the volt | bolt holding part of a chuck | zipper.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following description of the preferred embodiments is merely exemplary in nature.

  FIG. 1 schematically shows a projection welding apparatus 1 provided with a bolt supply device 40 according to an embodiment of the present invention. The projection welding apparatus 1 is a projection welding apparatus for joining a projection nut and a projection bolt 90 (see FIG. 6 etc.) to a work W (see FIG. 10 etc.) by projection welding.

  As shown in FIG. 1, the projection welding apparatus 1 is for supplying a robot 10 having a displaceable arm 11, a welding apparatus main body 20, a nut supply device 30 for supplying a projection nut, and a projection bolt 90. , The robot 10, the welding device body 20, the nut supply device 30, and the control device 100 (see FIG. 8) for controlling the operation of the bolt supply device 40.

  The robot 10 is an articulated industrial robot having three arms 11 pivotably connected to one another and a base 12. The three arms 11 have a base side arm 11a whose base end is connected to the base 12, a body side arm 11b whose welding device main body 20 is held at the tip, a tip end portion and a body side of the base side arm 11a. It is comprised with the intermediate arm 11c which connects with the base end side of the arm 11b. The base 12 is installed on a floor of a factory or the like, and the projection welding apparatus 1 is fixed to the floor or the like of the factory.

  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 pivots around the axis, each arm 11 pivots in the horizontal direction together with the welding device main body 20.

  The distal end of the base arm 11a and one end in the longitudinal direction of the intermediate arm 11c, and the base end of the main arm 11b and the other end of the intermediate arm 11c in the longitudinal direction are shafts 13 extending in the horizontal direction. It is connected to be able to rotate around. The welding apparatus main body 20 can be advanced and retracted in the direction perpendicular to both the vertical axis and the axis 13 by rotating the main body side arm 11 b and the intermediate arm 11 c around the axis 13.

  In the following description, the direction in which the shaft 13 extends is referred to as the left-right direction, and the direction perpendicular to both the axis and the shaft 13 in the vertical direction is referred to as the front-rear direction. Moreover, regarding the front-back direction, the side from which the welding apparatus main body 20 leaves the base 12 is called the front side, and the side where the welding apparatus 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 for moving the upper electrode 50 up and down, and a lower electrode 60.

<Upper electrode>
As shown in FIG. 1, the upper electrode 50 is held together with the upper cylinder 51 at the tip of the main body side arm 11 b via a support mechanism. The support mechanism includes an upper support 22 that supports the upper cylinder 51, and a lower support 23 that extends downward from the upper support 22 and extends toward the front and that is substantially L-shaped in a side view. Have. At the front end of the lower support portion 23, a lower holding portion 23a is provided which holds and holds the lower electrode 60 (strictly, a lower electrode holder 61 described later).

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

  The upper cylinder 51 is a fluid pressure cylinder, and raises and lowers the upper electrode 50 using oil pressure or air pressure. Although not shown, in the upper cylinder 51, a biasing member for biasing the upper electrode 50 upward is disposed. When the fluid is not supplied into the upper cylinder 51, the upper electrode 50 is moved upward (ie, raised) by the biasing force of the biasing member, while the fluid is supplied into the upper cylinder 51. And the upper electrode 50 is moved downward (i.e., lowered) when the fluid pressure by the fluid becomes a fluid pressure that generates a force that overcomes the biasing force of the biasing 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 in the vertical direction. A guide pin 80 described later is vertically movably inserted into the lower electrode holder 61.

  The lower electrode 60 has an electrode socket 62 mounted on the upper end portion of the lower electrode holder 61, and an electrode tip 63 fitted so as to cover the electrode socket 62 from the upper side. 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 located 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.

  As shown in FIG. 3, the lower end of the lower electrode holder 61 is held by the holder base 64. A lower cylinder 65 for raising and lowering the guide pin 80 is provided at a lower part of the holder base 64. The lower cylinder 65 is constituted by 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 FIG. 2 and FIG. 3, cooling for supplying cooling water for cooling the lower electrode 60 at the time of projection welding is performed on a portion near the lower side of the lower electrode holder 61 and above the holder base 64. A water supply unit 66 and a cooling water discharge unit 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 respectively extend straight outward in the radial direction of the lower electrode holder 61, and then extend obliquely downward in the radial direction. . Although illustration is omitted, a hose connected to a cooling water supply device configured by a water pump or the like is connected to the cooling water supply unit 66 and the discharge unit 67. The cooling water supplied from the cooling water supply device through the cooling water supply unit 66 flows in the lower electrode holder 61 to cool the lower electrode 60 during projection welding, and then passes through the cooling water discharge unit 67. It is designed to flow into the cooling water supply system.

  In the cylinder of the lower electrode holder 61, as shown in FIG. 3, the work W and the projection nut, and the liftable guide pin 80 for positioning the work W and the projection bolt 90, and the guide pin 80 And the resin rod 70 whose lower end is connected to the cylinder rod 65b of the lower cylinder 65 are inserted. It is done.

<guide pin>
As shown in FIG. 3, the guide pin 80 is provided at a rod portion 81 extending in the cylinder axial direction of the lower electrode holder 61, and an axial upper end of the rod portion 81 in the rod portion 81 and a projection nut And a bolt receiving portion 83 provided on the upper side of the nut receiving portion 82 and receiving the projection bolt 90.

  As shown in FIG. 3, the rod portion 81 of the guide pin 80 is recessed inward in the radial direction from the large diameter portion 81a extending vertically with a diameter slightly smaller than the inner diameter of the lower electrode holder 61 An intermediate portion 81c in which the depressed portion 81b is formed, a small diameter portion 81d having a diameter larger than the minimum diameter of the intermediate portion 81c and smaller in diameter than the large diameter portion 81a and extending vertically, and from the lower end of the small diameter portion 81d And a reduced diameter portion 81 e extending to decrease in diameter. As shown in FIG. 3, the middle portion 81c is formed below the large diameter portion 81a, and the small diameter portion 81d is formed below the middle portion 81c. The lower end portion of the reduced diameter portion 81 e is placed on the connecting screw 68. The large diameter portion 81a, the middle 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 upper side to the lower side in the axial direction of the rod portion 81 so as to be able to receive a plurality of types of projection nuts having different inner diameters. Specifically, the nut receiving portion 82 is smaller in diameter than the 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, and the first nut receiving portion 82a. And a second nut receiving portion 82b formed of a cylindrical body, the second nut receiving portion 82b being disposed on the upper side of the first nut receiving portion 82a. 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, and from the upper end of the first nut receiving portion 82a The second nut receiving portion 82b extends upward in the axial direction.

  The first nut receiving portion 82 a and the second nut receiving portion 82 b are both 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 82 a and the diameter of the second nut receiving portion 82 b are set according to the inner diameter of the projection nut joined to the workpiece W. For example, when there are a nut with an inner diameter of about 7 mm and a nut with a diameter of about 5 mm as a projection nut to be joined to the work W, the diameter of the first nut receiving portion 82a is smaller than 7 mm (for example 6.8 mm) While the diameter is set, the diameter of the second nut receiving portion 82b is set to a diameter (for example, 4.8 mm) smaller than 5 mm.

  The height of the first nut receiving portion 82 a and the height of the second nut receiving portion 82 b are set in accordance with the height of the projection nut joined to the work W.

  As shown in FIG. 3, the bolt receiving portion 83 is a protrusion that protrudes upward in the cylinder axial direction of the lower electrode holder 61 from a cylindrical body positioned on the uppermost side among the plurality of cylindrical bodies configuring the nut receiving portion 82. It is composed of More specifically, the bolt receiving portion 83 is formed of a conical or truncated cone-like protrusion protruding from the radial center of the second nut receiving portion 82b toward the upper side in the cylinder axial direction.

  As shown in FIG. 3, the maximum diameter of the cone or the truncated cone forming the bolt receiving portion 83 (the diameter of the connecting portion with the second nut receiving portion 82b) is smaller than the diameter of the second nut receiving portion 82b.

  The bolt receiving portion 83 is configured to be 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.

  As shown in FIG. 3, the guide pin 80 is installed on the connecting screw 68 in a state of being axially and radially held by the claw member 69. The claw member 69 is configured by four claws in the present embodiment. The claw members 69 have a screw side engaging portion 69a engaged with the connecting screw 68, four claw portions 69b respectively engaged with the depressed portion 81b of the guide pin 80, a screw side engaging portion 69a and respective claw portions 69b. And a connecting portion 69c connecting the two. The screw side engaging portion 69 a has a cylindrical shape that circumferentially covers a part of the connecting screw 68 in the axial direction. The four connecting portions 69c are arranged at equal intervals in the circumferential direction of the screw side engaging portion 69a, whereby the four claws 69b are also arranged at equal intervals in the circumferential direction.

  The connection portions 69c of the claw members 69 are each formed of an elastic member, and in the state where the claw portions 69b are engaged with the recessed portions 81b of the guide pins 80, the respective connection portions 69c are each resilient by their respective claw portions 69b. Is pressed inward in the radial direction of the guide pin 80 against the recess 81 b. Thereby, the guide pin 80 is held in the axial direction and the radial direction. That is, the guide pin 80 is held in the axial direction and the radial direction by the elastic force of the connecting portion 69 c of the claw member 69.

  As described above, the claw members 69 hold the guide pin 80 by pressing the claw portions 69 b toward the inner side in the radial direction of the guide pin 80 and thus the guide pin 80. In the holding force of the guide pin 80, the axial holding force is weaker than the radial holding force. Therefore, when the guide pin 80 is pulled upward with respect to the lower electrode holder 61, the guide pin 80 is pulled out of the lower electrode holder 61. Thus, when it is necessary to replace the guide pin 80, the guide pin 80 can be removed from the lower electrode holder 61. 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. Thus, the guide pin 80 can be easily replaced.

  As shown in FIG. 3, the claw member 69 is adapted to be accommodated in 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 inside of the lower electrode holder 61 and the through hole of the electrode socket 62.

  As described above, the connecting rod 68 is fastened to the upper end of the resin rod 70. Thus, the resin rod 70 holds the guide pin 80 via the connecting screw 68 and the claw member 69.

  Further, 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 is lifted, the resin rod 70 is also lifted together with the cylinder rod 65b. Then, as the resin rod 70 ascends, the guide pin 80 held by the resin rod 70 ascends. On the other hand, when air is discharged from the lower cylinder 65 and the cylinder rod 65b is lowered, the resin rod 70 is also lowered, and the guide pin 80 is lowered together with the resin rod 70.

  The lower end of the resin rod 70 floats from the bottom of the holder base 64 in the unloaded state where no downward force is applied to the guide pin 80, as shown in FIG. Specifically, in the present embodiment, a fixed amount of air is always supplied into the lower cylinder 65, and the cylinder rod 65b and the resin rod 70 are moved upward by the force based on the fixed amount of air. , And the resin rod 70 floats from the bottom of the holder base 64. Thus, in a no-load state where no downward force is applied to the guide pin 80, as shown in FIG. 3, the whole nut receiving portion 82 and bolt receiving portion 83 of the guide pin 80 and a part of the rod portion 81 The electrode tip 63 penetrates and is positioned above the electrode tip 63.

  The lower cylinder 65 is provided with a position sensor 101 (see FIG. 8) for detecting the position of the resin rod 70.

<Nut feeding 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 unit 33 and a nut standby unit 34. The nut supply unit 33 is connected by a not-shown nut supply source and a connector such as a tube. The nut guide device 32 has a guide cylinder 35, a nut supply rod (not shown) inserted in the guide cylinder 35, and an air cylinder (not shown) for driving the nut supply rod so as to be able to advance and retract. There is.

  The projection nut sent from the nut supply source via the nut supply unit 33 stands by in the nut standby unit 34. When the air cylinder is driven in a state in which the projection nut is in standby in the nut standby portion 34, the nut supply rod holds the projection nut in standby in the nut standby portion 34 and moves toward the guide pin 80. Go ahead. Thereafter, the projection nut is received by the nut receiving portion 82 of the guide pin 80. Thus, the projection nut is supplied from the nut supply device 30 to the position of the guide pin 80.

  In the present embodiment, as shown in FIG. 1, two nut supply devices 30 are provided. The two nut supply devices 30 supply projection nuts of different inner diameters. The configuration of the nut supply device 30 itself is the same for both of the two. If it is possible to sort projection nuts by the nut supply source and supply projection nuts of a desired inner diameter from a plurality of projection nuts having different inner diameters, one nut supply device 30 is provided. May be

<Volt supply device>
The bolt supply device 40, as shown in FIG. 1, includes a bolt shooter 41, a chuck 43 for receiving and holding the projection bolt 90 supplied from the bolt shooter 41, and a bolt guide for guiding the projection bolt 90 to the joining position of the workpiece W. And an apparatus 42. The bolt supply device 40 also includes a bolt supply source 47 in which a plurality of types of projection bolts 90 having different axial lengths are stored, as shown in FIG. 8, and the bolt shooter 41 includes the bolt supply source 47 and tubes. It is connected by the connector. The bolt supply source 47 has a selection device (not shown), and is configured to be able to supply a projection bolt 90 of a desired axial length by the selection device. The bolt guide device 42 has a guide cylinder 44 into which a rod 44a for guiding the chuck 43 to the position of the guide pin 80 is inserted, and an air cylinder (not shown) for driving the rod to be able to advance and retract.

  The chuck 43 is configured such that the pair of chuck levers 43a can be brought into contact with and separated from each other in the horizontal direction. As shown in FIG. 4, the chuck levers 43a are urged toward each other by springs 49, and in the unloaded state where the chuck levers 43a are not loaded, they abut in a horizontal direction. It has become. On the other hand, when a force that overcomes the biasing force of the spring 49 is applied to the chuck levers 43a in the direction in which the chuck levers 43a are separated from each other, the chuck levers 43a move in directions away from each other.

  As shown in FIGS. 4 to 7, a cup-shaped bolt holding portion 45 is formed on the tip end side (the side opposite to the rod 44 a) of the chuck 43. The bolt holding portion 45 includes a through hole 46 having a circular cross section, which is formed by the pair of chuck levers 43 a cooperating with each other and vertically penetrates. More specifically, halves of the through holes 46 are respectively formed in the pair of chuck levers 43a, and one through hole 46 is formed when the pair of chuck levers 43a are in contact with each other. It has become.

  As shown in FIG. 6, the portion of the bolt holding portion 45 which constitutes the through hole 46 is a tapered portion 45a which is inclined so as to decrease in diameter toward the lower side, and vertically from the lower side 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.

  The maximum value D1 (inner diameter of the upper end) of the inner diameter of the tapered portion 45a is larger than the diameter DH of the head portion 91 of the projection bolt 90, as shown in FIG. On the other hand, the minimum value D2 of the inner diameter of the tapered portion 45a (the inner diameter of the boundary portion with the straight portion 45b) is smaller than the diameter DH of the head 91 of the projection bolt 90 and the diameter DS of the shaft 92 of the projection bolt 90 Also slightly larger. The inner diameter of the straight portion 45b is equal to the minimum value D2 of the inner diameter of the tapered portion 45a.

  As shown in FIG. 6, the radial inner surface of the through hole 46 in the inner protrusion 45c is a tapered surface 46a that is inclined inwardly in the radial direction toward the lower side. The minimum value D3 of the inner diameter of the inner protrusion 45c is slightly smaller than the diameter DS of the shaft 92 of the projection bolt 90. The inner protrusion 45c is continuously provided along the circumferential direction of the through hole 46, as shown in FIG.

  As shown in FIG. 6, the straight portion 45 b constitutes a shaft holding portion that holds the shaft 92 of the projection bolt 90. The inner protruding portion 45 c constitutes a tip holding portion that holds the tip portion 93 of the projection bolt 90.

  Since the bolt holding portion 45 is configured to receive the tip end portion 93 of the projection bolt 90, the projection bolt 90 is held by the bolt holding portion 45 even if the axial length of the projection bolt 90 is different. The tip portion 93 of the head is always located at the height position of the inner protrusion 45c. That is, as shown in FIG. 7A, the axial length is shorter than the projection bolt 90 of FIG. 6 or as shown in FIG. 7B, the axial length is longer than the projection bolt 90 of FIG. However, the tip end portion 93 of the projection bolt 90 is positioned at the height position of the inner protrusion 45c. From this, the inner protrusion 45 c is a tip holding portion capable of receiving and holding the tip 93 of the projection bolt 90 regardless of the axial length of the projection bolt 90.

  In the bolt supply device 40, after the projection bolt 90 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 . Thereafter, the projection bolt 90 is received by the bolt receiving portion 83 of the guide pin 80 while being held by the chuck 43.

  The projection bolt 90 has an engagement recess 94 which is recessed toward the head portion 91 at the tip end portion 93, and as shown in FIGS. 10 to 12, the bolt receiving portion 83 of the guide pin 80 is The projection bolt 90 is received by engaging with the engagement recess 94 of the projection bolt 90. Further, on the side of the shaft portion 92 of the head portion 91 of the projection bolt 90, as shown in FIGS. 10 to 12, a weld portion 95 to be welded to the work W is formed in advance.

Control system
As shown in FIG. 8, the control device 100 outputs an operation signal to the robot 10 to move the welding device main body 20 to the welding portion of the workpiece W.

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

  The control device 100 outputs an operation signal to the bolt supply device 40 to supply the projection bolt 90 from the bolt supply source 47 to the bolt shooter 41 and the projection bolt 90 to the bolt holding portion 45 of the chuck 43 from the bolt shooter 41. Supply. The control device 100 outputs an operation signal to the bolt supply device 40 and drives the air cylinder of the bolt guide device 42 in a state where the projection bolt 90 is held by the bolt holding portion 45 to guide the projection bolt 90 Supply to 80 positions.

  The control device 100 outputs an operation signal to the upper cylinder 51 to raise and lower the upper electrode 50. In addition, the control device 100 outputs an operation signal to the upper electrode 50 and the lower electrode 60 to cause a current to flow between the upper electrode 50 and the lower electrode 60.

  The control device 100 calculates the elevation amount of the resin rod 70 from the detection result of the position sensor 101. The control device 100 determines whether the currently supplied projection nut or projection bolt 90 has a desired standard, based on the amount of elevation of the resin rod 70 calculated from the position sensor 101.

<Joining of projection bolt>
Next, an operation of joining the projection bolt 90 to the workpiece W by the projection welding apparatus 1 will be described. In the following description, when the diameter of the shaft 92 of the projection bolt 90 is smaller than 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 case where the diameter of the hole H is smaller than the first nut receiving portion 82a of the guide pin 80 and larger than the diameter of the second nut receiving portion 82b will be described. The workpiece W is made of, for example, a steel plate, and is transported by a workpiece transport device (not shown).

  First, the workpiece W is conveyed, the workpiece W is disposed on the upper side of the guide pin 80, and the hole H of the workpiece W and the guide pin 80 are roughly aligned. This alignment can be performed by the robot 10.

  Next, the work W is moved toward the lower electrode 60, and the guide pin 80 is inserted into the hole H. At this time, since the diameter of the hole H formed in the work W is smaller than 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. The first nut receiving portion 82a of the guide pin 80 does not penetrate the hole H, and only the second nut receiving portion 82b and the bolt receiving portion 83 of the guide pin 80 penetrate the hole H. . A portion around the hole H in the work W is placed on the upper end of the first nut receiving portion 82a. Since the portion around the hole H in the work W is placed on the upper end of the first nut receiving portion 82a, the bolt receiving portion 83 of the guide pin 80 is a hole of the work W as shown in FIG. At the stage of penetrating the portion H, a gap is formed between the electrode tip 63 of the lower electrode 60 and the lower surface of the work W.

  The bolt feeder 40 is then activated. The projection bolt 90 is supplied from the bolt supply source 47 to the bolt holding portion 45 of the chuck 43 via the bolt shooter 41. As shown in FIG. 6, FIG. 7, FIG. 9 and FIG. 10, the supplied projection bolt 90 receives and holds the tip end portion 93 by the inner projection 45c, and the portion near the tip end of the shaft 92 is a straight portion 45b. It is held.

  Subsequently, after the projection bolt 90 is held by the bolt holding portion 45, the air cylinder is driven, the rod advances toward the guide pin 80, and the projection bolt 90 is supplied to the position of the guide pin 80. Ru. The projection bolt 90 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 engagement recess 94 of the projection bolt 90 to receive the projection bolt 90. As a result, the projection bolt 90 is disposed in the vicinity (in detail, immediately above) of the hole H of the workpiece W.

  After the projection bolt 90 is supplied to the position of the guide pin 80, the upper cylinder 51 is driven to move the upper electrode 50 downward (downward). The upper electrode 50 is moved further downward after coming into contact with the head portion 91 of the supplied projection bolt 90 as shown in FIG. As a result, the guide pin 80 is pushed down to the lower side of the lower electrode holder 61 in the cylinder axial direction with the workpiece W and the projection bolt 90.

  Specifically, when the upper electrode 50 is moved toward the lower electrode 60 by the upper cylinder 51, the tip 93 of the projection bolt 90 presses the tapered surface 46a of the inner projection 45c. The pressing force for pressing the tapered surface 46a is converted into a horizontal force by the tapered surface 46a, and the converted horizontal force slightly separates the pair of chuck levers 43a of the chuck 43. Thereby, the tip end 93 and the shaft 92 of the projection bolt 90 are moved downward. The work W moves downward together with the guide pin 80 by the guide pin 80 being pushed downward to the lower axial direction of the lower electrode holder 61.

  Thereafter, when the head portion 91 of the projection bolt 90 abuts on the tapered portion 45 a of the bolt holding portion 45, the head portion 91 presses the tapered portion 45 a. The pressing force for pressing the tapered portion 45a is converted into a horizontal force by the tapered portion 45a, and the converted horizontal force causes the pair of chuck levers 43a of the chuck 43 to be displaced away from each other. Thereby, as shown in FIG. 12, the upper electrode 50 can be moved further downward. Then, the tip 93 and the shaft 92 of the projection bolt 90 are inserted into the hole H of the work W, and the projection bolt 90 (particularly, the weld 95 of the projection bolt 90) abuts on the upper surface of the work W .

  As described above, the pair of chuck levers 43 a are separated from each other by the projection bolt 90 being pressurized by the downward movement of the upper electrode 50 in a state where the projection bolt 90 is held by the bolt holding portion 45. To be displaced.

  After the projection bolt 90 abuts on the upper surface of the workpiece W, as shown in FIG. 13, the chuck 43 retracts. At this time, since the chuck 43 is in a no-load state, the biasing force of the spring 49 brings the pair of chuck levers 43a into contact with each other.

  The upper cylinder 51 tries to move the upper electrode 50 further downward even after the projection bolt 90 abuts on the upper surface of the workpiece W and the chuck 43 retracts. The projection bolt 90 is pressed to the work W side by the advancing operation to the lower side of the upper electrode 50. Since the electrode tip 63 of the lower electrode 60 is placed 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, the work W is not moved downward. , And receives pressure from the upper electrode 50. The lower electrode 60 presses the work W toward the projection bolt 90 with a reaction force against the pressing force from the upper electrode 50. As a result, the workpiece W and the projection bolt 90 are pressed and held between the upper electrode 50 and the lower electrode 60.

  Then, in a state in which the work W and the projection bolt 90 are sandwiched between the upper electrode 50 and the lower electrode 60 (a state in which the work W and the projection bolt 90 are sandwiched), energization is performed between the upper electrode 50 and the lower electrode 60 A bonding current for projection welding is passed between the upper electrode 50 and the lower electrode 60. While the junction current is flowing, the pressurization of the projection bolt 90 by the upper electrode 50 is continued. The contact portion between the upper surface of the workpiece W and the welding portion 95 of the projection bolt 90 is softened by the joining current and the pressure, and the welding portion 95 is crushed in the pressing direction (that is, the lower side). . At this time, plastic flow occurs between the upper surface of the workpiece W and the welding portion 95 of the projection bolt 90, and rapid diffusion bonding is performed. Thus, the projection bolt 90 is joined to the work W.

  As described above, the workpiece W and the projection bolt 90 are joined by projection welding.

  As described above, in the present embodiment, the bolt holding portion 45 is provided with the inner projecting portion 45 c (tip holding portion) for receiving and holding the tip portion 93 of the projection bolt 90, so that the axial length of the projection bolt 90 is obtained. Regardless, the tip 93 of the projection bolt 90 is held by the inner projection 45c. Therefore, in the state of being held by the bolt holding portion 45, in the bolt holding portion 45, the tip end portion 93 of the projection bolt 90 has the height position of the inner projection 45c regardless of the axial length of the projection bolt 90. Located in As a result, when the chuck 43 is moved in order to arrange the tip end portion 93 of the projection bolt 90 having different axial lengths in the vicinity of the hole H of the workpiece W, the movement of the chuck 43 is made There is no need to change the aspect. Therefore, the projection bolt 90 can be appropriately supplied to the position of the hole H of the workpiece W without changing the movement of the chuck 43 holding the projection bolt 90.

  Further, in the present embodiment, since the straight portion 45b is provided in the bolt holding portion 45, the shaft portion 92 of the projection bolt 90 is held by the straight portion 45b, so that the projection bolt 90 can be held stably. Can.

  Furthermore, in the present embodiment, the radial inner surface of the through hole 46 in the inner protrusion 45c is a tapered surface 46a that is inclined inwardly in the radial direction toward the lower side, so the projection bolt 90 can be used as the upper electrode Since the pair of chuck levers 43a can be displaced away from each other only by pressing the workpiece W side (downward) by moving downward 50, the projection bolt 90 can be bored in the workpiece W The operation at the time of supply to the H position can be facilitated. In addition, since a special device is not necessary to displace the pair of chuck levers 43a apart from each other, the enlargement of the chuck 43 can be prevented.

  Further, in the present embodiment, since the inner protrusion 45 c is continuously provided along the circumferential direction of the through hole 46, the inner protrusion 45 c appropriately receives and holds the tip 93 of the projection bolt 90. Will be able to Further, the force at the time of pressing the projection bolt 90 toward the work W can be appropriately converted to the force in the direction in which the pair of chuck levers 43 a separate, and the position of the hole H of the work W Can be made easier when supplying the

<Modification example>
FIG. 14 shows a modified example of the present embodiment, in which the configuration of the inner protrusion 45c is changed from the above-described embodiment.

  In this modification, a plurality (six in FIG. 14) of the inner protrusions 45 c are provided intermittently along the circumferential direction of the through hole 46. The radially inner surface of the through hole 46 in each of the inner protrusions 45 c is a tapered surface 46 a that is inclined inwardly in the radial direction toward the lower side. Even if the inner protrusion 45c is configured as in this modification, the inner protrusion 45c can function as a tip holding portion that receives and holds the tip 93 of the projection bolt 90. Therefore, even in this modification, the projection bolt 90 can be appropriately supplied to the position of the hole H of the workpiece W without changing the movement of the chuck 43 holding the projection bolt 90.

  Further, for example, if the plurality of inner protrusions 45c are concentrated at the circumferential center of the half of the through hole 46 formed in each chuck lever 43a and positioned, the lower side of the upper electrode 50 can be obtained. By this movement, the pressing force when the tip end portion 93 of the projection bolt 90 presses the tapered surface 46a of the inner projecting portion 45c is efficiently converted into a horizontal force. As a result, the force in the direction in which the pair of chuck levers 43 a separate can be generated efficiently, and the operation for supplying the projection bolt 90 to the position of the hole H of the work W can be further facilitated.

(Other embodiments)
The present invention is not limited to the above embodiment, and can be substituted without departing from the scope of the claims.

  For example, in the above embodiment, the upper electrode 50 is moved downward, and the force for pressing the projection bolt 90 downward (work W side) is used to displace the pair of chuck levers 43a in the direction away from each other. However, the present invention is not limited to this, and a device may be provided to displace the pair of chuck levers 43a in a direction away from each other without using the pressurization of the projection bolt 90 by the upper electrode 50. In this case, it is not necessary to provide the bolt holding portion 45 with the tapered portion 45a or to make the radially inner surface of the through hole 46 in the inner projecting portion 45c into the tapered surface 46a. However, since the chuck 43 may be enlarged or the cost may be increased, as in the above embodiment, the bolt holding portion 45 is provided with the tapered portion 45a, and the radially inner side of the inner protruding portion 45c. Preferably, the pressure of the projection bolt 90 by the upper electrode 50 is used to displace the pair of chuck levers 43a in the direction away from each other by making the surface of the tapered surface 46a.

  In the above-described embodiment, the projection nut or projection bolt 90 is joined to one of the holes H formed in the work W by one projection welding device 1, but there are a plurality of projection welding devices 1 May be At this time, when a plurality of hole portions H are formed in the work W, projection welding can be simultaneously performed on the hole portions H of a plurality of loading spaces by a plurality of projection welding apparatuses 1.

  Moreover, in the above-mentioned embodiment, although the welding apparatus main body 20 was hold | maintained at the robot 10, it is not hold | maintained at the robot 10, but may be fixed to the floor surface etc. of a factory. That is, the projection welding apparatus 1 may be a stationary welding apparatus.

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

  The present invention is suitable, for example, in a projection welding apparatus for joining a projection bolt to a vehicle body component of an automobile, as a bolt supply apparatus for supplying the projection bolt to a welding position of the projection bolt.

40 bolt supply device 42 bolt guide device 43 chuck 43a chuck lever 45 bolt holding portion 45a tapered portion 45b straight portion 45c inner protruding portion (tip holding portion)
46 through hole 46a tapered surface 47 bolt supply source 50 upper electrode 60 lower electrode 90 projection bolt 91 projection bolt head 92 projection bolt shaft 93 projection bolt tip W work H hole D1 maximum value of inner diameter of tapered portion D2 Minimum inside diameter of tapered section DH Projection bolt head diameter

Claims (4)

With the shaft portion of the projection bolt inserted in the hole formed in the workpiece, the workpiece and the projection bolt are held between the upper electrode and the lower electrode, and the workpiece and the projection bolt are welded by projection welding. A bolt supply device for supplying the projection bolt to the position of the hole of the work in order to join the
A bolt supply source in which a plurality of types of projection bolts having different axial lengths are stored;
A chuck consisting of a pair of chuck levers that can move away from each other;
A bolt holding portion provided on the chuck and receiving and holding the projection bolt supplied from the bolt supply source in a state where the pair of chuck levers are in contact with each other;
And a guide device for guiding the projection bolt to the joining position of the work while the projection bolt is held by the bolt holding portion.
The chuck guides the projection bolt to the position of the hole of the work by the guide device and then separates the pair of chuck levers from each other to thereby move the tip end portion and the shaft portion of the projection bolt to the work Configured to be inserted into the holes of the
A bolt supply device characterized in that the bolt holding portion is provided with a tip holding portion capable of receiving and holding the tip end portion of the projection bolt regardless of the axial length of the projection bolt. In the bolt supply device according to claim 1,
The bolt holding portion includes a through hole having a circular cross section which is configured by the pair of chuck levers cooperating and vertically penetrates,
The portion forming the through hole in the bolt holding portion is a tapered portion inclined such that the diameter of the through hole decreases toward the lower side, and a straight extending in a substantially uniform diameter in the vertical direction from the lower end of the tapered portion A portion, and an inner projecting portion provided at the lower end of the straight portion and projecting inward from the straight portion,
In the tapered portion, while the maximum value of the inner diameter is larger than the diameter of the head of the projection bolt, the minimum value of the inner diameter is smaller than the diameter of the head of the projection bolt and the diameter of the shaft of the projection bolt Greater than
The straight portion holds the shaft portion of the projection bolt,
The bolt supply device according to claim 1, wherein the inward protruding portion constitutes the tip end holding portion. In the bolt supply device according to claim 2,
The radially inner surface of the through hole in the inner protrusion is a tapered surface inclined downward in the radial direction. In the bolt supply device according to claim 2 or 3,
The bolt supply device according to claim 1, wherein the inward protruding portion is provided continuously along the circumferential direction of the through hole.

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