JP2009255151A - Method for welding weld nut and electrode apparatus for weld nut welding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding apparatus capable of easily welding a nut to a workpiece to be welded without boring a positioning hole into the workpiece to be welded. <P>SOLUTION: The welding apparatus comprises: a cylindrical electrode holder 1; an upper electrode 2 attached to a tip of the electrode holder 1 to communicate with a through-hole 2a at the center; and a guide pin 3 slidably enclosed in the cylindrical electrode holder 1, passing through the through-hole 2a and protruding from the through-hole 2a. A workpiece to be welded is placed on a lower electrode arranged so as to be opposed below the upper electrode 2. When the electrode holder 1 is taken down in its inserted condition into a screw hole of a weld nut by the guide pin 3, the upper electrode 2 contacts the weld nut. In this state, current is applied across the upper electrode 2 and the lower electrode; then, a current flows into a production of the weld nut. Therefore the weld nut is weld to the workpiece to be welded, because the production is melted by electric resistant heat generated at that time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a weld nut welding apparatus for welding a weld nut between upper and lower electrodes.

  Conventionally, when joining a nut to a member to be welded (iron plate), a projection welding machine as shown in Patent Documents 1 to 3 is widely used. As shown in FIG. 10, projection welding using such a projection welder is performed by inserting a guide pin 95 of the lower electrode device 90 into a positioning hole 100 a formed through the member to be welded 100, and welding the member to be welded. 100 is placed on the lower electrode 96 of the lower electrode device 90, and the guide pin 95 is inserted into the screw hole 101b of the projection nut 101 having a plurality of projections 101a formed on the seating surface. The electrode is pressed against the projection nut 101, current is concentrated on the projection 101 a, the projection 101 a is melted by the electric resistance heat generated at this time, and the projection nut 101 is welded to the workpiece 100 by spot welding. is there.

However, in such projection welding, since it is necessary to form a positioning hole 100a through which the guide pin 95 is inserted into the member to be welded 100, the positioning hole 100a is formed in the member to be welded 100 like an air tank or a fuel tank. If the nut is not allowed to be formed, the operator positions the nut with a jig on the member to be welded 100, and the operator uses the arc welding torch as shown in Patent Document 4 to We decided to arc weld. However, in this method, it is necessary to manufacture a jig, and there is a problem that it takes time to join the nut to the member to be welded because the operator performs arc welding on the entire circumference of the nut.
Japanese Patent Laid-Open No. 06-238460 JP-A-10-58154 JP 09-295162 A JP 05-269580 A

  An object of the present invention is to solve the above-mentioned problems and to provide a welding instrument that can easily weld a nut to a member to be welded without opening a positioning hole in the member to be welded.

The invention according to claim 1, which has been made to solve the above problems,
Place the member to be welded on the lower electrode,
The weld nut is placed on the welded member with the projection of the weld nut directed to the welded member side and the guide pin that slidably penetrates the upper electrode inserted into the screw hole of the weld nut.
The weld nut is welded to the member to be welded by applying a current between the upper electrode and the lower electrode while pressing the weld nut between the upper electrode and the lower electrode.

The invention according to claim 2 is the invention according to claim 1,
The tip of the guide pin has a sharp shape,
A positioning recess is formed on the upper surface of the member to be welded,
The positioning nut is positioned with respect to the member to be welded by engaging the positioning recess with the tip of the guide pin.

The invention according to claim 3, which is an optimal apparatus for realizing the claim according to claim 1,
A cylindrical electrode holder;
An upper electrode attached to the lower end of the electrode holder and having a through hole communicating with the electrode holder in the center;
An upper electrode device having a guide pin that is slidably housed in the electrode holder and has a lower end protruding from a through hole of the electrode;
It is comprised from the lower electrode opposingly arranged below the said upper electrode apparatus.

The invention according to claim 4 is the invention according to claim 3,
The tip of the guide pin has a sharp shape.

The invention according to claim 5 is the invention according to claim 3 or claim 4,
The guide pin is biased toward the distal end side of the guide pin.

The invention according to claim 6 is the invention according to claims 3 to 5,
A guide groove that communicates the inside and outside of the electrode holder is formed along the axial direction of the electrode holder,
A handle protruding from the guide groove to the outside of the electrode holder is attached to the proximal end of the guide pin.

The invention according to claim 7 is the invention according to claim 6,
An engaging part orthogonal to the guide groove is formed at the upper end of the guide groove, and the handle is engaged with the engaging part so that the guide pin is held above the electrode holder. And

The invention according to claim 8 is the invention according to claims 3 to 7,
The contact portion of the guide pin with the screw hole of the weld nut is made of an insulating material.

The invention according to claim 9 is the invention according to claims 3 to 8,
The electrode holder is provided with a water cooling jacket having a cooling water flow path therein.

The invention according to claim 10 is the invention according to claim 9,
The water-cooled jacket has a mounting portion having a shape slightly larger than the outer shape of the electrode holder, and is formed in a vertically extending manner. An inner peripheral surface of the mounting portion is formed as a recess over the entire circumference, and an electrode is formed on the mounting portion. A space formed by the recessed portion and the outer peripheral surface of the electrode holder through the holder is a cooling water flow path.

The invention according to claim 1, which has been made to solve the above problems,
Place the member to be welded on the lower electrode,
The weld nut is placed on the welded member with the projection of the weld nut directed to the welded member side and the guide pin that slidably penetrates the upper electrode inserted into the screw hole of the weld nut.
The weld nut is welded to the member to be welded by applying a current between the upper electrode and the lower electrode while pressing the weld nut between the upper electrode and the lower electrode.
For this reason, projection welding (spot welding) can be performed without forming a positioning hole in the member to be welded, and the nut can be welded to the member to be welded in a short time and easily.

The invention according to claim 2 is the invention according to claim 1,
The tip of the guide pin has a sharp shape,
A positioning recess is formed on the upper surface of the member to be welded,
The positioning nut is positioned with respect to the member to be welded by engaging the positioning recess with the tip of the guide pin.
For this reason, it is possible to prevent the welding position of the weld nut from being welded to the member to be welded, and it is possible to reliably weld the weld nut to the target position of the member to be welded.

The invention according to claim 3 is a cylindrical electrode holder, an upper electrode attached to a lower end of the electrode holder and having a through hole communicating with the electrode holder in the center, and slidable inside the electrode holder And an upper electrode device having a guide pin having a lower end protruding from the through hole of the electrode, and a lower electrode disposed oppositely below the upper electrode device.
When the electrode holder is lowered in a state where the screw hole of the weld nut is inserted into the guide pin, the upper electrode comes into contact with the weld nut, and in this state, when a current is passed between the upper electrode and the lower electrode, the weld An electric current flows through the projection of the nut, the electric resistance heat generated at this time melts the projection, and the weld nut is welded to the member to be welded. For this reason, projection welding (spot welding) can be performed without forming a positioning hole in the member to be welded, and the nut can be welded to the member to be welded in a short time and easily.

The invention according to claim 4 is the invention according to claim 3, characterized in that the tip of the guide pin has a sharp shape.
For this reason, when a positioning recess is formed on the member to be welded by a punch or the like, the tip of the guide pin is engaged with the positioning recess, and it is possible to prevent the welding position of the weld nut from being welded to the member to be welded. The weld nut can be reliably welded to the target position of the member to be welded.

The invention according to claim 5 is characterized in that, in the invention according to claim 3 or claim 4, the guide pin is urged toward the tip side of the guide pin.
For this reason, it becomes possible to prevent the guide pin from coming into contact with the member to be welded and prevent the weld nut from coming off from the guide pin, and to prevent poor welding.

According to a sixth aspect of the present invention, in the third to fifth aspects of the present invention, the guide groove that communicates the inside and the outside of the electrode holder is formed along the axial direction of the electrode holder, and the electrode is formed from the guide groove. A handle protruding outward from the holder is attached to the proximal end of the guide pin.
For this reason, when the operator lifts the handle upward, the guide pin slides upward, so that it is possible to improve workability when the guide pin is inserted into the screw hole of the weld nut.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, an engagement portion orthogonal to the guide groove is formed at the upper end of the guide groove, and the handle is engaged by the engagement portion, whereby the guide The pin is configured to be held above the electrode holder.
For this reason, the member to be welded to which the weld nut is welded can be easily taken out from the spot welder (upper electrode for weld nut welding, lower electrode).

The invention described in claim 8 is characterized in that, in the invention described in claims 3 to 7, the contact portion of the guide pin with the screw hole of the weld nut is made of an insulating material.
Therefore, no current flows from the screw hole of the weld nut, and it is possible to prevent the screw hole from melting.

The invention according to claim 9 is the invention according to claims 3 to 8, characterized in that a water cooling jacket having a cooling water flow passage is provided in the electrode holder.
For this reason, when the cooling water is circulated through the cooling water flow path and the electrode holder is cooled, the upper electrode is also cooled, so that it is possible to prevent the electrode from being softened by the heat generated by projection welding.

The invention according to claim 10 is the invention according to claim 9,
The water-cooled jacket has a mounting portion having a shape slightly larger than the outer shape of the electrode holder, and is formed in a vertically extending manner. An inner peripheral surface of the mounting portion is formed as a recess over the entire circumference, and an electrode is formed on the mounting portion. A space formed by the recessed portion and the outer peripheral surface of the electrode holder through the holder is a cooling water flow path.
For this reason, since the outer peripheral surface of the electrode holder is directly cooled over the entire circumference, the electrode holder can be cooled more efficiently.

  FIG. 4 shows an explanatory view of the weld nut 60 welded by the weld nut welding electrode device of the present invention, and the weld nut 60 will be described below. 4, (1) is a side view of the weld nut 60, (2) is a top view of the weld nut 60, and (3) is a bottom view of the weld nut 60. FIG. Although the weld nut 60 shown in FIG. 4 has a cylindrical shape, the weld nut 60 welded by the electrode device for welding nut welding of the present invention is not limited to this shape. A threaded hole 60 a that communicates with the weld nut 60 is formed at the center of the weld nut 60. A plurality of projections 60 b are projected from the bottom surface of the weld nut 60. The projection 60b concentrates an electric current when performing projection welding, melts during welding, melts into a member to be welded, and is integrated with the member to be welded.

(Electrode device for weld nut welding)
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The electrode device for welding nut welding of the present invention is composed of an upper electrode device 10 and a lower electrode 20 (shown in FIGS. 5 to 9) disposed opposite to the upper electrode device 10. 1 is a front view of the upper electrode device 10, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a cross-sectional view of FIG. The upper electrode device 10 mainly includes an electrode holder 1, an upper electrode 2, a guide pin 3, a handle 4, a coil spring 5, and a closing member 6.

  The electrode holder 1 has a substantially cylindrical shape. The electrode holder 1 is made of a copper alloy such as pure copper or chromium copper. The inner diameter of the lower part 1 e of the electrode holder 1 is smaller than the inner diameter of the upper part 1 f of the electrode holder 1. A screw groove is threaded on the inner surface of the lower end of the electrode holder 1 to form an attachment portion 1a. Further, a screw groove is also threaded on the inner surface of the upper end of the electrode holder 1 to form an attachment portion 1b. As shown in FIG. 1, the electrode holder 1 is formed with a guide groove 1c communicating between the inside and the outside. The guide groove 1c is formed along the longitudinal direction of the electrode holder 1, and an engaging portion 1d orthogonal to the guide groove 1c is formed at the upper end of the guide groove 1c.

  The upper electrode 2 has a cylindrical shape, and a through hole 2 a is formed in the center of the upper electrode 2. The upper electrode 2 is made of a copper alloy such as beryllium copper, chromium copper, zirconium metal, alumina dispersion strengthened copper. The upper part of the upper electrode 2 has an outer diameter smaller than that of the other part, and a thread is formed on the outer surface of the part to form a mounting part 2b. The attachment portion 2 b of the upper electrode 2 is screwed to the attachment portion 1 a of the electrode 1 holder, and the upper electrode 2 is attached to the tip of the electrode holder 1.

  The closing member 6 has a substantially cylindrical shape. A screw thread is formed in the middle of the closing member 6 and serves as an attachment portion 6a. In addition, the lower end portion of the closing member 6 has a smaller outer diameter than the other portions, and serves as a spring support portion 6b. The attaching portion 6 a of the closing member 6 is screwed to the attaching portion 1 b of the electrode holder 1, and the closing member 6 is attached to the proximal end of the electrode holder 1.

  The guide pin 3 includes a base portion 3f, a handle attachment portion 3e, a slide portion 3a, and a guide portion 3b in order from the top in FIG. The base 3f has a cylindrical shape. The handle attachment portion 3e is also cylindrical, and is coaxially attached to the lower end of the base portion 3f. The outer diameter of the base portion 3f is smaller than the outer diameter of the handle attachment portion 3e. The outer diameter of the handle mounting portion 3e is smaller than the inner diameter of the upper portion 1f of the electrode holder 1, but larger than the inner diameter of the lower portion 1e of the electrode holder 1.

  The slide portion 3a has a vertically long cylindrical shape and is coaxially attached to the lower end of the handle attachment portion 3e. The outer diameter of the slide part 3a is smaller than the outer diameter of the handle mounting part 3e. Further, the outer diameter of the slide portion 3 a is smaller than the inner diameter of the lower portion 1 e of the electrode holder 1. The base portion 3f, the handle attachment portion 1e, and the slide portion 3a are made of stainless steel or the like. The guide portion 3b has a vertically long cylindrical shape, is attached to the tip of the slide portion 3a coaxially with the slide portion 3a, and the slide portion 3a and the guide portion 3b are integrated. The base portion 3f and the handle attachment portion 3e are located in the upper portion 1f of the electrode holder 1, and the slide portion 3a is located in the lower portion 1e of the electrode holder 1. That is, the guide pin 3 is slidably accommodated in the electrode holder 1. Further, the slide part 3 a and the guide part 3 b of the guide pin 3 are slidable with respect to the upper electrode 2.

  The guide portion 3b is made of KCF (stainless steel, the surface of which is subjected to an insulating coating treatment) or the like, and at least the surface is made of an insulating material. The distal end portion of the guide portion 3b has a smaller outer diameter than the other portion (base portion 3e), and serves as a screw hole insertion portion 3d. The outer diameter of the screw hole insertion portion 3 d is slightly smaller than the inner diameter of the screw hole 60 a of the weld nut 60 and is inserted into the screw hole 60 a of the weld nut 60. The tip 3c of the screw hole insertion portion 3d has a sharp shape.

  As shown in FIG. 3, the upper ring-shaped member 9 is attached to the base 3f. The upper ring-shaped member 9 is made of a low friction material such as phenol resin. The outer diameter of the upper ring-shaped member 9 is slightly larger than the outer diameter of the handle attachment portion 3e. For this reason, the guide pin 3 slides smoothly in the electrode holder 1 without the handle support portion 3 e coming into direct contact with the inner surface of the upper portion 1 f of the electrode holder 1. In the present embodiment, the outer diameter of the upper ring-shaped member 9 is 17.5 mm, whereas the outer diameter of the handle mounting portion 3e is 17.0 mm.

  As shown in FIG. 3, a lower ring-shaped member 8 is attached to the inner lower end of the electrode holder 1 upper portion 1f. That is, the slide portion 3 a passes through the lower ring-shaped member 8. The lower ring-shaped member 8 is made of a low friction material such as phenol resin.

  A coil spring 5 is accommodated in the upper portion 1 f of the electrode holder 1. The upper end of the coil spring 5 is supported by a spring support portion 6 b of the closing member 6. As shown in FIG. 3, the height dimension of the upper ring-shaped member 9 is smaller than the height dimension of the base portion 3f. For this reason, the base portion 3 f enters the lower end of the coil spring 5 and holds the lower end of the coil spring 5. The coil spring 5 presses the handle attachment portion 3 e via the upper ring-shaped member 9. With such a configuration, the guide pin 3 is always urged toward the distal end 3 c side of the guide pin 3.

  The handle 4 includes a shaft portion 4a and a grip portion 4b. The shaft portion 4 a is attached to the handle attachment portion 3 e of the guide pin 3 and is exposed to the outside of the electrode holder 1 from the guide groove 1 c of the electrode holder 1. The grip part 4b is attached to the tip of the shaft part 4a.

  In FIG. 3, when the handle 4 is lowered to the bottom, the slide portion 3a of the guide pin 3 passes through the through hole 2a of the upper electrode 2, and the guide portion 3b passes through the through hole 2a of the upper electrode 2. It is in the state which protrudes completely from.

  On the other hand, when the handle 4 is completely pulled upward along the guide groove 1c, the guide portion 3b of the guide pin 3 is completely accommodated in the electrode holder 1 and the upper electrode 2. . In this state, when the handle 4 is rotated and the shaft portion 4a of the handle 4 is engaged with the engaging portion 1d of the electrode holder 1, the guide pin 3 is held above the electrode holder and does not fall. become.

  The electrode holder 1 is held by a power feeding unit (not shown) of the spot welder, and current is supplied from the power feeding unit to the upper electrode 2 through the electrode holder 1. As will be described later, the power feeding portion of the spot welder moves downward during welding.

  As shown in FIGS. 1 to 3, a water cooling jacket 7 is attached to the lower end of the electrode holder 1. The water cooling jacket 7 is composed of a water cooling jacket main body 7a, O-rings 7d and 7e, an inflow jack 7b, an outflow jack 7c, and a fixing screw 7f.

  The water cooling jacket body 7a has a block shape and is made of a metal having excellent corrosion resistance such as brass or stainless steel. In the present embodiment, the water cooling jacket body 7a has a substantially cylindrical shape. The water cooling jacket main body 7a is formed with a mounting portion 7g that communicates vertically. The cross-sectional shape of the mounting portion 7g is circular. The inner diameter of the mounting portion 7 g is slightly larger than the outer diameter of the electrode holder 1. The electrode holder 1 is inserted into the attachment portion 7g of the water cooling jacket body 7a, and the water cooling jacket 7 is attached to the outer peripheral surface of the electrode holder 1.

  As shown in FIG. 3, a cooling water circulation recess 7 h is formed in the inner peripheral surface of the attachment portion 7 g so as to cover the entire periphery. As shown in FIG. 3, the space constituted by the cooling water circulation recess 7h and the outer peripheral surface of the electrode holder 1 is a cooling water flow path 7i through which the cooling water flows. As shown in FIG. 1, an inflow port 7m and an outflow port 7n that open to the outer surface of the water-cooling jacket body 7a communicate with the cooling water circulation recess 7h. An inflow jack 7b is attached to the inflow port 7m. An outflow jack 7c is attached to the outflow port 7n.

  O-ring housing recesses 7j and 7k are respectively formed in recesses over the entire circumference at positions adjacent to the upper and lower sides of the cooling water circulation recess 7h on the inner surface of the mounting portion 7g. O-rings 7d and 7e are housed and attached to the O-ring housing recesses 7j and 7k, respectively. These O-rings 7d and 7e seal the space between the outer peripheral surface of the electrode holder 1 and the water-cooling jacket main body 7a, thereby preventing the cooling water from leaking from the cooling water channel 7i.

As shown in FIGS. 1 and 2, the water cooling jacket main body 7a is formed with a screw hole 7p for a fixing screw that communicates with the mounting portion 7g from the outer surface of the water cooling jacket main body 7a. A fixing screw 7 f is screwed into the fixing screw screw hole 7 p, and the tip of the fixing screw 7 f presses the electrode holder 1, and the water cooling jacket body 30 is fixed to the lower end of the electrode holder 1. In the embodiment shown in the figure, the fixing screw 7f is a so-called moth screw.
(Usage method of electrode device for weld nut welding)

  Below, the usage method of the electrode apparatus for weld nut welding of this invention is demonstrated. A positioning recess 50a is formed on the surface of the welded member 50 to which the weld nut 60 is welded by stamping with a punch or the like. As shown in FIG. 5, the member to be welded 50 is placed on the lower electrode 20 disposed to face the lower side of the weld nut welding electrode device 40 of the present invention. The lower electrode 20 has a flat surface at the upper end and is cylindrical in this embodiment, but is not limited to this shape. Next, the member to be welded 50 is moved, and the member to be welded 50 is positioned by aligning the positioning recess 50a of the member to be welded 50 with the tip 3c of the guide portion 3b. Since the tip 3c of the guide portion 3b has a sharp shape, when the positioning recess 50a of the member 50 to be welded matches the tip 3c of the guide portion 3b, the tip 3c of the guide portion 3b has a sense of moderation. It engages with 50 positioning recesses 50a. In this state, the position of the welded member 50 is fixed.

  Next, the handle 4 is pulled up to move the guide pin 3 upward, and the screw hole insertion portion 3d is inserted into the screw hole 60a of the weld nut 60 with the projection 60b facing the welded member 50 (see FIG. 6). Status). When the handle 4 is released in this state, the guide pin 3 is urged to the tip 3c side by the coil spring 5, so that the guide pin 3 is lowered downward (state shown in FIG. 7).

  When the welding switch of the spot welder is turned ON in the state of FIG. 7, the power feeding portion of the spot welder is lowered, the electrode holder 1 is lowered, the upper electrode 2 is in contact with the weld nut 60, and the upper electrode 2 is welded nut 60 is pressurized. (State of FIG. 8) In this way, when a current is passed between the upper electrode 2 and the lower electrode 20 with the weld nut 60 being pressed between the upper electrode 2 and the lower electrode 20, a projection 60b of the weld nut 60 is obtained. The electric current flows through the electric resistance heat generated at this time, the projection 60b is melted, and the weld nut 60 is welded to the welded member 50. At this time, since the screw hole 60a of the weld nut 60 is guided through the screw hole insertion portion 3d, the welding position of the weld nut 60 does not shift. Moreover, since the surface of the guide portion 3b of the guide pin 3 that contacts the screw hole 60a of the weld nut 60 is made of an insulating material, no current flows from the screw hole 60a of the weld nut 60, and the screw hole 60a Prevents melting.

  When the projection welding of the weld nut 60 to the member 50 to be welded is completed, the power feeding portion of the spot welder is raised upward, and the electrode holder 1 is also moved upward. Next, when the operator lifts the grip portion 4b of the handle 4 and rotates the handle 4 in a state where the shaft portion 4b of the handle 4 is in contact with the upper end of the guide groove 1c, the shaft portion of the handle 4 is rotated. 4 b engages with the engaging portion 1 d engaging portion of the electrode holder 1. (State of FIG. 9) In this state, the guide pin 3 is held above the electrode holder 1 and does not slide downward, so that the welded member 50 welded with the weld nut 60 can be easily attached to the spot welder (upper part). It can be taken out from the electrode device 10 and the lower electrode 20).

  During projection welding, the cooling water flowing in from the inflow jack 7b flows through the cooling water flow path 7i and cools the tip of the electrode holder 1. For this reason, the upper electrode 2 is also cooled to prevent the upper electrode 2 from being softened and easily consumed by the heat generated by projection welding. In addition, the cooling water which cooled the front-end | tip of the electrode holder 1 is discharged | emitted from the outflow jack 7c.

  Although the present invention has been described above in connection with the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. The weld nut welding method and the weld nut welding electrode device with such changes are also within the technical scope without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Must be understood as encompassed by.

It is a front view of the upper electrode for weld nut welding. It is a side view of the upper electrode for weld nut welding. It is sectional drawing of the upper electrode for weld nut welding. It is explanatory drawing of a weld nut. It is explanatory drawing which shows a use condition. It is explanatory drawing which shows a use condition. It is explanatory drawing which shows a use condition. It is explanatory drawing which shows a use condition. It is explanatory drawing which shows a use condition. It is explanatory drawing of the conventional weld nut welding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode holder 1a Attachment part 1b Attachment part 1c Guide groove 1d Engagement part 1e Lower part 1f Upper part 2 Upper electrode 2a Through hole 2b Attachment part 3 Guide pin 3a Slide part 3b Guide part 3c Tip 3d Screw hole insertion part 3e Handle attachment part 3f Base part 3g Spring support part 4 Handle 4a Shaft part 4b Grip part 5 Coil spring 6 Closure member 6a Mounting part 6b Spring support part 7 Water cooling jacket 7a Water cooling jacket body 7b Inflow jack 7c Outflow jack 7d O ring 7e O ring 7f Attachment screw 7g 7h Cooling water flow recess 7i Cooling water flow path 7j O-ring storage recess 7k O-ring storage recess 7m Inlet 7n Outlet 7p Screw hole for fixing screw 8 Lower ring member 9 Upper ring member 10 Upper electrode device 20 Lower electrode 50 Welded Element 0a positioning recess 60 weld nut 60a threaded hole 60b projection 90 lower electrode device 95 the guide pins 96 the lower electrode 100 hole 101 for weld members 100a positioned projection nut 101a projection 101b screw hole

Claims (10)

Place the member to be welded on the lower electrode,
The weld nut is placed on the welded member with the projection of the weld nut directed to the welded member side and the guide pin that slidably penetrates the upper electrode inserted into the screw hole of the weld nut.
A welding nut welding method comprising welding a weld nut to a member to be welded by applying a current between the upper electrode and the lower electrode while pressing the weld nut between the upper electrode and the lower electrode. The tip of the guide pin has a sharp shape,
A positioning recess is formed on the upper surface of the member to be welded,
The welding nut welding method according to claim 1, wherein the positioning nut is positioned with respect to a member to be welded by engaging the positioning recess with a tip of the guide pin. A cylindrical electrode holder;
An upper electrode attached to the lower end of the electrode holder and having a through hole communicating with the electrode holder in the center;
An upper electrode device having a guide pin that is slidably housed in the electrode holder and has a lower end protruding from a through hole of the electrode;
An electrode device for welding nut welding, comprising: a lower electrode disposed oppositely below the upper electrode device.   The electrode device for welding nut welding according to claim 3, wherein the tip of the guide pin has a sharp shape.   The electrode device for welding nut welding according to claim 3 or 4, wherein the guide pin is urged toward the tip end side of the guide pin. A guide groove that communicates the inside and outside of the electrode holder is formed along the axial direction of the electrode holder,
The electrode device for welding nut welding according to any one of claims 3 to 5, wherein a handle protruding from the guide groove to the outside of the electrode holder is attached to a proximal end of the guide pin.   An engaging part orthogonal to the guide groove is formed at the upper end of the guide groove, and the handle is engaged with the engaging part so that the guide pin is held above the electrode holder. An electrode device for welding nut welding according to claim 6.   The electrode device for welding nut welding according to any one of claims 3 to 7, wherein a contact portion of the guide pin with a screw hole of the weld nut is made of an insulating material.   The electrode device for welding nut welding according to any one of claims 3 to 8, wherein a water cooling jacket having a cooling water flow path therein is provided in the electrode holder.   The water-cooled jacket has a mounting portion having a shape slightly larger than the outer shape of the electrode holder, and is formed in a vertically extending manner. An inner peripheral surface of the mounting portion is formed as a recess over the entire circumference, and an electrode is formed on the mounting portion. 10. The spot welding electrode according to claim 9, wherein a space formed by the recessed portion and the outer peripheral surface of the electrode holder is formed as a cooling water flow path through the holder.

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