JP2009172655A - Electric resistance welder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate contact between guide pins and also to dispense with adjustment of an elastic force. <P>SOLUTION: An electric resistance welder is equipped with: a component holding rod 4 which is inserted into a upper electrode 1, is movable integrally with the upper electrode 1 and relative to the upper electrode 1; and a projected part 8 and a stopper 11 which, when the upper electrode 1 moves integrally with the component holding rod 4 and when a nut N held on the component holding rod 4 comes close before a planar workpiece W, stop the movement of the component holding rod 4 while making the upper electrode 1 continue to move. After the component holding rod 4 stops moving by the projected part 8 and the stopper 11, the nut N breaks away from the component holding rod 4 by the continuously moving upper electrode 1 and is pressed against the planar workpiece W by the upper electrode 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric resistance welding machine that welds perforated parts such as nuts (perforated parts) to a plate-like workpiece.

  2. Description of the Related Art Conventionally, a welding machine that welds a projection nut (perforated part) to a steel plate part (perforated part) is known as an electric resistance welder (see, for example, Patent Document 1).

In the electric resistance welding machine described in Patent Document 1, an upper electrode (movable electrode) and a lower electrode (fixed electrode) are arranged corresponding to the steel plate part side and the nut side, respectively, and the lower end is always lowered by the elastic force on the upper electrode side. A holding guide pin with a tapered guide pin that protrudes from the lower surface of the upper electrode, a nut that supports the nut from below on the lower electrode side, and an upper end that always protrudes from the upper surface of the lower electrode by elastic force Is provided. The tapered guide pin has a tapered portion at the lower end, and this tapered portion descends integrally with the upper electrode during welding, passes through the pilot hole of the steel plate part, and holds the holding guide pin. It pushes down and moves the nut closer to the lower electrode, and also fits the taper hole of the nut and positions the nut.
Japanese Patent No. 3624279 (FIGS. 1 and 2)

  However, according to the electric resistance welding machine described in the above patent document, the tapered guide pin and the holding guide pin are in contact with each other every time the nut is welded to the steel plate part. Abrasion, insulation retention, and durability are required. In addition, it is necessary to set the elastic force that causes the tapered guide pin to protrude downward and the elastic force that causes the entry guide pin to protrude upward so that the holding guide pin is pushed down by the tapered guide pin. There is a need to adjust these elastic forces.

  An object of the present invention is to provide an electric resistance welder that does not cause contact between guide pins as in the prior art and that does not require adjustment of elastic force.

  An electric resistance welding machine of the present invention is an electric resistance welding machine for welding a perforated part to a plate-shaped workpiece, wherein the electrode on the perforated part side includes a movable electrode. A component holding rod that is inserted and movable together with the movable electrode, and that is movable with respect to the movable electrode, and the movable electrode moves together with the component holding rod to hold the component Stopper means for stopping the movement of the component holding rod while continuing the movement of the movable electrode when the perforated component held by the rod approaches to the front of the plate-like workpiece; After the component holding rod stops moving, the perforated component is separated from the component holding rod by the movable electrode that continues to move, and is pressed against the plate-like workpiece by the movable electrode. And characterized in that it is.

  According to the present invention, when the perforated part approaches to the front side of the plate-like workpiece, the movement of the part holding rod is stopped by the stopper means, and the perforated part is detached from the part holding rod by the movable electrode while continuing the movement. Since it is configured to press against the workpiece, the guide pins do not come into contact with each other as in the prior art, and the adjustment of the elastic force becomes unnecessary.

  Here, the electrode on the plate-like workpiece side includes a guide pin that enters the hole of the perforated component detached from the component holding rod and guides the perforated component to the welding position of the plate-like workpiece. Then, it becomes possible to reliably guide the perforated part to the welding position.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram conceptually showing the main part of an electric resistance welding machine according to an embodiment of the present invention, FIG. 2 is a process diagram for explaining an electric resistance welding method, and FIG. The enlarged view of the main processes in the process drawing of illustration is shown, respectively.

  The electric resistance welding machine shown in FIG. 1 is a welding machine that resistance welds a nut N, which is a perforated part, to the upper surface of a plate-like workpiece W, and includes an upper electrode 1 and a lower electrode 2.

  The upper electrode 1 is a movable electrode that is driven up and down by an electrode driving device 3 disposed on the main body frame (not shown) side of the welding machine.

  The electrode driving device 3 is constituted by an air cylinder, for example. When the electrode driving device 3 is an air cylinder, the upper electrode 1 is fixed to an electrode horn (not shown) connected to the piston rod side of the air cylinder 3.

  A component holding rod 4 is inserted into the upper electrode 1. The tip portion 5 of the component holding rod 4 constitutes a component holding portion, and the nut N is held by the component holding portion 5. The component holding part 5 is composed of, for example, an elastic part that can be compressed and deformed. The component holding rod 4 descends with respect to the upper electrode 1, and the elastic part 5 protrudes from the lower surface 1 a of the upper electrode 1 to the hole Na of the nut N The nut N is configured to be held by the elastic restoring force of the elastic portion 5 when inserted. The component holding portion 5 is not limited to an elastic portion, and the component holding portion 5 is configured by a magnet that holds the nut N by magnetic attraction force or a vacuum attraction portion that holds the nut N by vacuum attraction force. May be.

  The component holding rod 4 is driven up and down by the rod driving device 6 with respect to the upper electrode 1. The rod driving device 6 is constituted by, for example, a double rod type air cylinder. When the rod driving device 6 is a double rod type air cylinder, the component holding rod 4 is fixedly connected to the lower piston rod 7 of the air cylinder 6.

  An extension rod 9 having a protruding portion 8 that protrudes in a direction orthogonal to the moving direction of the component holding rod 4 extends from the component holding rod 4. The extension rod 9 is fixedly connected to the upper piston rod 10 of the air cylinder 6 when the rod driving device 6 is a double rod type air cylinder. The extension rod 9 moves up and down integrally with the component holding rod 4 via the air cylinder 6.

  A stopper portion 11 is disposed on the main body frame side of the welding machine. When the component holding rod 4 is lowered, the stopper portion 11 is installed at a position where it can come into contact with the protruding portion 8 of the extending rod 9 that is being lowered together with the component holding rod 4. The lowering of the extension rod 9 is stopped, and consequently the lowering of the component holding rod 4 is stopped.

  The lower electrode 2 is disposed on the main body frame side of the welding machine, is a fixed electrode, and a plate-like workpiece W is set on the upper surface 2a.

  The lower electrode 2 has a guide pin 12. The guide pin 12 can project from the upper surface 2a of the lower electrode 2 and is inserted into the hole Wa of the plate-like workpiece W to position the plate-like workpiece W. Further, when receiving the nut N from the component holding portion 5 of the component holding rod 4, the guide pin 12 enters the hole Na of the nut N and guides the nut N to the welding position of the plate-like workpiece W. The guide pin 12 may be either movable back and forth or fixed.

  Next, an electric resistance welding method will be described based on FIGS.

  2A shows a state in which the upper electrode 1 and the component holding rod 4 are both held at the upper end position, and the component holding portion 5 of the component holding rod 4 is accommodated in the upper electrode 1. (A) shows that one nut N is set by a supply device (not shown) immediately below the lower surface 1a of the upper electrode 1, and a plate-like workpiece W is set on the upper surface 2a of the lower electrode 2. It represents the state.

  From the state (a), when air is supplied to the upper passage 6 a of the double rod type air cylinder 6, the piston 13 of the air cylinder 6 is pushed downward, and the component holding rod 4 is lowered via the lower piston rod 7. The component holding portion 5 of the component holding rod 4 protrudes downward from the lower surface 1a of the upper electrode 1, enters the hole Na of the nut N, and holds the nut N by an elastic return force due to compression deformation. (B) represents a state in which the component holding rod 4 is lowered to the lower end position.

  Next, the upper electrode 1 is lowered by the electrode driving device 3. (C) represents the lowering of the upper electrode 1. Further, FIG. 3D and FIG. 3A show a state where the upper electrode 1 is further lowered from the state of FIG. 3C and the protruding portion 8 of the extension rod 9 hits the stopper portion 11. This state corresponds to the case where the component holding portion 5 of the component holding rod 4 is not in contact with the guide pin 12 of the lower electrode 2 and the nut N approaches to the front of the plate-like workpiece W. In this state, the supply of air to the upper passage 6a of the air cylinder 6 has already been released, and the piston 13 can be moved upward.

  When the protruding portion 8 of the extension rod 9 hits the stopper portion 11, the component holding rod 4 that has been lowered integrally with the upper electrode 1 cannot be lowered, and only the upper electrode 1 continues to descend. . With the lowering of the upper electrode 1, the nut N held by the component holding portion 5 of the component holding rod 4 is pushed down by the lower surface 1 a of the upper electrode 1, and comes off from the component holding portion 5. FIG. 3 (e) and FIG. 3 (b) show a state in which the nut N is detached from the component holding portion 5. FIG.

  The nut N detached from the component holding part 5 falls on the upper surface Wb of the plate-like workpiece W while the upper electrode 1 is descending when the fall speed of the nut N is faster than the descending speed of the upper electrode 1. FIG. 3F and FIG. 3C show a state where the nut N has dropped on the upper surface Wb of the plate-like workpiece W. When the nut N is dropped, the guide pin 12 of the lower electrode 2 enters the hole Na of the nut N, and the nut N is guided to the welding position of the plate-like workpiece W by the guide pin 12. In addition, when the falling speed of the nut N is slower than the descending speed of the upper electrode 1, the nut N is pushed down by the upper electrode 1.

  After the nut N reaches the upper surface Wb of the plate-like workpiece W, the upper electrode 1 descends to the upper surface Nb of the nut N and pressurizes the nut N. FIG. 3G and FIG. 3D show a state where the upper electrode 1 pressurizes the nut N. During this pressurization, a voltage is applied between the upper electrode 1 and the lower electrode 2, and the nut N is resistance-welded to the plate-like workpiece W. In addition, after this welding is completed, the upper electrode 1 is raised by the air cylinder 3. Further, air is supplied to the lower passage 6 b of the air cylinder 6 while the upper electrode 1 is being raised, and the piston 13 is held above the air cylinder 6. Therefore, the upper electrode 1 and the component holding rod 4 return to the state shown in FIG.

  As described above, the electric resistance welder according to the present embodiment is an electric resistance welder that welds the nut N (perforated part) to the plate-like workpiece W, and includes the upper electrode 1 (the electrode on the perforated part side). ) Is inserted into the upper electrode 1 (movable electrode) and can be moved integrally with the upper electrode 1 (movable electrode), and can be moved to the upper electrode 1 (movable electrode). On the other hand, the movable component holding rod 4 and the upper electrode 1 (movable electrode) move integrally with the component holding rod 4, and the nut N (perforated component) held by the component holding rod 4 is a plate-like workpiece. Provided with a protruding portion 8 and a stopper portion 11 (stopper means) for stopping the movement of the component holding rod 4 while continuing the movement of the upper electrode 1 (movable electrode) when approaching before W, the protruding portion 8 and the stopper Part 11 (stopper means ), The nut N (perforated part) is separated from the part holding rod 4 by the upper electrode 1 (movable electrode) which is continuing to move, and the plate is moved by the upper electrode 1 (movable electrode). Pressed against the workpiece W.

  According to the present embodiment, when the nut N (perforated part) approaches to the front of the plate-like workpiece W, the movement of the part holding rod 4 is stopped by the protruding part 8 and the stopper part 11 (stopper means), and the movement is continuing. Since the nut N (perforated part) is separated from the part holding rod 4 and pressed against the plate-like workpiece W by the upper electrode 1 (movable electrode), the contact between the guide pins does not occur as in the prior art. Moreover, it is not necessary to adjust the elastic force.

  Further, the lower electrode 2 (electrode on the plate workpiece W side) enters the hole Na of the nut N (perforated component) detached from the component holding rod 4, and the nut N (perforated component) is inserted into the plate workpiece W. Since the guide pin 12 for guiding to the welding position is provided, the nut N (perforated part) can be reliably guided to the welding position.

  In the above-described embodiment, the nut N is held on the upper electrode 1 side and the plate-like workpiece W is set on the lower electrode 2 side. However, the configuration may be reversed upside down. In this case, the nut N detached from the component holding rod 4 moves to the plate-like workpiece W while being supported by the upper surface of the lower electrode (movable electrode). Further, the present invention can be applied even if the guide pin 12 on the lower electrode 2 side is omitted and the hole Wa is deleted from the plate-like workpiece W. In the above embodiment, the lower electrode 2 is a fixed electrode. However, the plate-like workpiece W is fixed between the upper electrode 1 and the lower electrode 2 and is configured by a movable electrode that can be raised toward the plate-like workpiece W. However, the same effect as the above-described embodiment can be produced. In the above embodiment, the nut N is used as the perforated part. However, the present invention is applicable to any part having a hole Na like the nut N.

  In addition, when the component holding part 5 of the component holding rod 4 is comprised by a vacuum suction part, it is necessary to control the start timing and completion | finish timing of vacuum suction, but these control can be performed comparatively easily.

It is the block diagram which showed notionally the principal part of the electrical resistance welding machine which concerns on one Embodiment of this invention. It is process drawing for demonstrating the electrical resistance welding method. FIG. 3 is an enlarged view of a main process in the process diagram shown in FIG. 2.

Explanation of symbols

W Plate work
N nut (perforated part)
Na hole 1 Upper electrode (perforated part side electrode, movable electrode)
2 Lower electrode (electrode on the plate workpiece side)
4 Parts holding rod 8 Protruding part (stopper means)
11 Stopper (stopper means)
12 Guide pin

Claims (2)

An electric resistance welding machine for welding a perforated part to a plate-shaped workpiece, wherein the perforated part side electrode is a movable electrode,
A component holding rod that is inserted into the movable electrode and is movable together with the movable electrode, and is movable with respect to the movable electrode;
When the movable electrode moves integrally with the component holding rod and the perforated component held by the component holding rod approaches to the front of the plate-like workpiece, the movement of the movable electrode is continued. Stopper means for stopping the movement of the component holding rod, and
After the movement of the component holding rod by the stopper means is stopped, the perforated component is detached from the component holding rod by the movable electrode that continues to move, and is pressed against the plate-like workpiece by the movable electrode. And electric resistance welding machine.   The electrode on the plate-shaped workpiece side includes a guide pin that enters the hole of the perforated component detached from the component holding rod and guides the perforated component to the welding position of the plate-shaped workpiece. The electric resistance welder according to claim 1.

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