JP2006283884A - Welding nut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a method for projection-welding a machine element to the specified position of a welding target plate placed on a plate electrode by using the plate electrode as one electrode. <P>SOLUTION: At least one flange part 20 is integrally provided on the outer circumference of a nut body 10 to be screwed on a bolt or a screw having a female screw threaded in the axial center. At least three protrusions 30 are dispersed on the rear face of this flange part 20. Preferably, each protrusion part 30 formed on the rear face of this flange part 20 is composed of the block body partly having a flat face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a weld nut, and more particularly, a weld nut used when welding onto a steel plate or the like by projection welding, and can be welded with minimal heating of the threaded portion thereof. The present invention relates to a welding nut that can be welded by pushing (or projecting part) toward the nut axis.

  Of resistance welding, projection welding is essentially a welding method in which a large current is intensively flowed locally to form a stone-like melted portion (nugget) and welded in the same manner as spot welding. In spot welding, this is achieved by the shape of the electrode, whereas in projection welding, the current and pressure are concentrated depending on the shape of the welded material to be welded. A projection (protrusion) is provided on a part of the welded material. Is different in achieving it.

  For this reason, in projection welding, it is desired to have a structure capable of performing resistance welding with high heat generation efficiency by concentrating current and pressure without damaging the performance and structure of the workpieces to be welded. Nevertheless, nuts having a shape to be joined by projection welding, for example, a weld nut, are desired, but few weld nuts improved to such a shape have been proposed.

  That is, projection welding is generally used when the heat capacity difference between two workpieces to be welded is large. For example, in the case of welding between a nut and a steel plate, a projection (or projection) is provided on the nut having a larger heat capacity than that of the steel plate, and the heat balance is adjusted between the steel plate and the welding. In order to perform this heat balance, the shape of the projection provided on the nut depends on the heat balance, and ultimately this determines the quality of the projection welding. Depending on how the projection shape is used, thick nuts can be welded well to thin steel plates, and from this surface, screws, bolts, nuts, etc. can also be welded to steel plates. However, even when welding is performed in this way, the welding is performed by applying a pressure current with a bolt interposed between the pair of electrodes. For this reason, in order to increase the joint strength at the time of welding, it is necessary to pass a certain amount of current through the threaded portion of the nut. For this reason, when a certain amount of current is passed through the nut body, the nut body itself becomes red-hot and spatter adheres to the thread surface, which often impairs the tightening function of the welded nut. Furthermore, the proposed welding nut has a simple protrusion protruding outward, and the projection often spreads outward due to the pressure applied during welding, which is not preferable from the standpoint of the appearance of the product alone.

  As described above, the shape and structure of the projection formed in advance is very important for the welding nut. Nonetheless, most of the techniques proposed for projection welding are welding methods and welding apparatuses, and none have been proposed for the purpose of improving the projection formed by adding to the nut.

  For example, it is not necessary to refer to Japanese Patent Application Laid-Open Nos. 2004-202570 and 2004-268133, and the most recently proposed technology related to projection welding is a welding nut positioning technology and its supply when welding is mostly performed. Technology. In short, there is no improvement in the shape and structure of the projection according to the actual example.

  First, the latter electric resistance welding apparatus described in Japanese Patent Application Laid-Open No. 2004-268133 is supported by at least a workpiece to be welded, for example, a steel plate part, which is a base member, and is supported by a support material or a support base. The fixed electrode is in close contact with the back surface of the steel plate, and is energized. Corresponding to this fixed electrode, a movable electrode that moves up and down is provided. The movable electrode is a welding machine in which a steel plate part to be welded, for example, a welding nut is held. The movable electrode is configured as a portable movable electrode unit, and the movable electrode unit is configured such that the insertion portion is received by a receiving portion formed integrally with the base member. Accordingly, a steel plate or the like is placed on the fixed electrode (that is, the lower electrode) supported by the base member, and a nut or the like that is held by the magnet (magnet) by the movable electrode (that is, the upper electrode) is supplied thereon. This type of welding machine is projection welded. For this reason, while the steel plate is positioned by the base member, the upper movable electrode moves under the control of the receiving portion fixed to the base member. A welding position of a nut or the like held by a movable electrode by a magnet is set.

  On the other hand, the former Japanese Patent Application Laid-Open No. 2004-202570 relates to the structure of the upper movable electrode in the latter welding machine. While holding the welding nut at the tip of the supply rod of the electrode via a protrusion, the welding nut is attracted and held by a magnetic force such as a magnet at the tip of the supply rod, and the position of the protruding piece relative to the welding nut is set. The supply rod is advanced obliquely downward or substantially horizontally at the set position, and the welding nut is supplied in a state where the guide pin of the lower fixed electrode slightly enters the screw hole of the welding nut.

  As described above, there is hardly any improvement in the shape of the weld nut in the conventional example, and the nut 1 shown in FIGS. 4 and 5 is exemplified. That is, the projection 5 is configured by projecting the projection 5 obliquely downward from the lower end of the outer periphery of the nut 1. In FIGS. 3 and 4, reference numeral 2 denotes a screw thread, 3 denotes a positioning guide, 4 denotes a magnet, 5 denotes a projection, and 6 denotes a supply rod.

  However, this nut merely concentrates the current applied to the nut 1 itself on the projection 5. In particular, when the nut 1 is thick, the screw thread 2 of the nut is inevitably damaged by the current, and spatter adheres, which is not preferable.

  Further, when the nut 1 is pressed from above and below, a considerable load is applied to the projection 5 projecting obliquely downward from the lower end of the nut 1, and the projection 5 remains spread out toward the outer periphery due to the applied pressure. Absent. In particular, since a large current and voltage and pressure are applied at the initial stage of welding, the projection 5 often breaks down from the seat or breaks from the base.

From these points, in projection welding, it is necessary to improve the shape structure of the nut itself and to concentrate and weld the current to the projection 5 without flowing current to the nut body as much as possible during welding. In particular, due to the formation of the projection 5, only the projection 5 that precedes the initial stage of welding is locally melted, so that the volume of the melted portion expands, whereby the nut 1 and the corresponding steel plate 8 are lifted or welded. The part which does not occur occurs locally and is not desirable.
JP 2004-202570 A JP 2004-268133 A

  The present invention aims to improve the above-mentioned points, specifically, it is a shape that can be welded by energizing only the projection part when applying pressure by the upper and lower electrodes from above, and the other steel plate at the time of welding, etc. We propose a welding nut with a shape that can be quickly positioned.

  First, according to the present invention, at least one flange portion is integrally provided on the outer periphery of a nut body that is threaded into a shaft and fastened to a bolt or screw, and at least three protrusions are provided on the back surface of the flange portion. It is characterized by being distributed.

  Moreover, each protrusion provided on the back surface of the flange portion is constituted by a block body having a flat surface in part.

  Further, the surface of the flange portion is formed as an inclined surface that is inclined downward toward the outer periphery.

  In addition, a guide guide having an axis common to the nut body is integrally provided on the bottom surface of the nut body.

  Moreover, the guide guide protrudes longer than the flat surface of each projection part provided in the back surface of the flange part.

  Further, the guide guide is formed in an annular shape.

  In addition, an annular recess is formed between the guide guide and each protrusion provided on the back surface of the flange portion.

  Since the welding bolt according to the present invention has such a configuration, the projection can be pressurized and energized with little current flowing through the nut body during welding, and projection welding can be performed without impairing the performance of the nut body.

  In addition, even if spatter is generated during welding, it does not adhere to the thread surface of the nut body, and the flange portion is pressed by the welding pressure. Can be welded with almost no leaving.

  The present invention will be described in more detail with reference to the illustrated embodiments as follows.

  FIG. 1 is a plan view of a welding nut according to one embodiment of the present invention.

  2 is a cross-sectional view taken along the line AA in FIG.

  FIG. 3 is an explanatory view when the welding nut shown in FIGS. 1 and 2 is welded onto a plate such as a steel plate.

  FIG. 4 is an explanatory view of one conventional welding nut.

  FIG. 5 is an explanatory view of another welding nut according to the prior art.

  First, in FIG. 1, FIG. 2 and FIG. 3, reference numeral 100 generally indicates a weld nut according to one embodiment of the present invention, and the weld nut 100 includes a nut body 10, a flange portion 20, a projection (or projection portion 30). ). A nut body 10 is a nut used as a normal fastening element. A female screw 11 is cut in parallel with the shaft center on the inner surface of the nut body 10, and a bolt or a male screw cut on the outer periphery of the screw is screwed to the female screw 11. It is tightened and tightened.

  At least one flange portion 20 is integrally provided on the outer periphery of the nut body 10. In the case of being provided integrally, it is possible to manufacture the flange portion 20 separately and attach it by welding or other means, but as usual, it can be integrally formed via a die by cold forging or the like. .

  Moreover, although it can also comprise cyclic | annular form so that the whole outer periphery of the flange part 20 may be covered, it can disperse | distribute to each place and can provide at least 1 or 2 or more. In addition, at least one protrusion 30 is provided as a projection on the back surface of the flange portion 20, and thus the projection is also provided so that the pressure energization is concentrated on the projection welding.

  Generally speaking, as described above, projection welding is a technique in which two materials to be welded that originally have different heat capacities, such as nuts and steel plates, are joined together in a heat balanced manner. In this respect, the number of protrusions 30 where current concentrates and the degree of dispersion are determined by the thickness and thermal properties of the counterpart steel plate 40. In particular, when an aluminum material having excellent thermal conductivity is used in place of the steel plate 40, sufficient consideration must be given.

  In terms of the strength of the welded joint obtained, the protrusions 30 need to be dispersed. Further, in terms of power concentration, the flange portions 20 can be configured to be dispersed as much as possible, and the protrusion portions 30 can be individually provided on each flange portion 20. On the other hand, if the flange portion 20 is configured in a distributed manner, it is difficult to balance and harmonize the applied pressure during welding.

  From such a point, as shown in FIG. 1 and FIG. 2, the flange portion 20 is integrally formed, and at least two, usually three or more, are dispersed on the back surface thereof, and the protrusion 30 is integrally formed. A flange inclined surface 21 inclined downward is formed on the surface of the flange portion 20. When the inclined surface 21 is configured in this way, when a downward pressing force is applied from the direction of the arrow in FIG. 3, the flange portion 20 is pressurized as a component force so as to be directed in the axial direction, and the nut body 10 is It can be firmly welded to the steel plate 40.

  The shape of the protrusion 30 can be configured in any shape as long as power concentration can be achieved. However, in the present invention, it is necessary not only to concentrate power but also to average the downward pressure applied during welding. From this surface, it is preferable to form a triangular trapezoid as shown by a dotted line in FIG.

  For this reason, at the initial stage of projection welding, the protrusion 30 is heated and heated locally due to current concentration, and can be immediately removed even if a so-called floating phenomenon occurs due to an increase in volume locally occurring in the weld. That is, the flange inclined surface 21 has a predetermined gradient (for example, 20 to 35 °). For this reason, when the directly applied pressure is applied to the flange inclined surface 21, the applied pressure applied to the flange portion 20 varies depending on how the gradient is taken. In other words, when a direct pressure is applied at the beginning of welding, the acting portion is the inclined flange inclined surface 21, and therefore the magnitude of the applied pressure varies depending on the gradient of the inclined surface 21. However, as the welding progresses, the force applied to the welding as the applied pressure changes due to the inclined surface gradient of the inclined surface 21, and as the gradient decreases, it acts as an increased pressure of the direct type. For this reason, the pressurizing force and current immediately under the initial stage of welding are not applied as they are, the volume expansion of the welded portion is relaxed, and the nut portion does not peel off. Further, as the welding progresses, the inclined surface 21 is destroyed, so that the applied pressure acts as it is, the welded portion is melted, and so-called nuggets are gradually enlarged to form a good weld joint. Is obtained.

  From this point, the gradient is preferably about 20 to 35 °. When the angle is less than 20 °, the prevention of initial volume expansion becomes insufficient, and when the angle exceeds 35 °, the applied pressure and current conduction are impaired by the sliding of the electrode.

  Further, at least one protrusion 30 is provided on the back surface of the flange portion 20 having the inclined surface 31 formed on the front surface, and the protrusion 30 is preferably configured as a block body having a triangular trapezoidal cross section. A flat pedestal surface 32 is formed on a part of the projecting portion 30, and these are integrated to form a triangular trapezoidal block body. That is, each projection 30 is integrated with the flange portion 20 to form a block body having a triangular trapezoidal cross section, so that the two inclined surfaces 31 and 31 of each projection 30 intersect each other toward the axis. A flat pedestal surface 32 is formed at the crossing portion of the two inclined surfaces 31, 31 that are configured and intersect. (This is shown by a dotted line in FIG. 1) Further, the surface of the block body is partitioned by the two inclined surfaces 31 and the flat pedestal surface 32 to form a triangular trapezoid. While configured in such a shape, the surface of the flange portion 20 is configured as an inclined surface 31 inclined downward toward the outer periphery, and the pressure applied by the upper electrode is received by the inclined surface 31 as shown in FIG.

  For this reason, when welding is performed by applying a downward pressing force from the direction of the arrow in FIG. 3, an initial pressing force is applied to the flange portion 20 and the projecting portion 30 at the initial stage and heating is performed along the inclined surface 31. While the welded portion flows, it is bonded to the surface of the steel plate 40 and welded.

  Further, a guide guide 50 having a common axis with the nut body 10 is integrally provided on the bottom surface of the nut body 10. The guide guide 50 is for positioning the welding nut 100 at a predetermined position on the steel plate 40, and is particularly effective when the mounting hole 41 is formed in advance on the steel plate 40 to be welded. However, even if the mounting hole 41 is not formed in advance depending on the steel plate 40, it is sufficient to perform relative position control between the steel plate 40 and the electrode. In this case, it is not always necessary to attach the guide guide 50. There is no.

  Further, the guide guide 50 protrudes longer than the flat pedestal surface 32 of each protrusion 30 provided on the back surface of the flange portion 20. That is, as shown in FIG. 3, the pedestal surface 32 is seated on the surface of the steel plate 40 to form a so-called projection, and this pedestal surface 32 achieves projection welding by concentration of applied pressure and current. Therefore, it is not preferable to make the pedestal surface 32 too large, but if it is too small, the previously mentioned place is lost. In this sense, the width is at least about 0.8 mm or more (preferably about 3 mm).

  Further, the guide guide 50 is configured in an annular shape. This means that an annular shape is preferable in order to prevent the occurrence of spatter occurring during projection welding and its adhesion to the thread surface.

  In addition, an annular recess 60 is formed between the guide guide 50 and each protrusion 30. This annular recess 60 surrounds the periphery of the nut body 10 by the guide guide 50 and is surrounded by the annular recess 60 to prevent spatter from adhering to the thread surface during welding.

  The present invention can be widely used not only for attaching nuts on steel plates, but also for attaching screws and bolts.

It is a top view of the welding nut concerning one example of the present invention. It is sectional drawing on the arrow AA line of FIG. It is explanatory drawing at the time of welding the welding nut shown in FIG. 1 and FIG. 2 on plates, such as a steel plate. It is explanatory drawing of one welding nut of a prior art example. It is explanatory drawing of the other welding nut of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nut main body 20 Flange part 21 Flange inclined surface 30 Protrusion part 31 Inclined surface 32 Base surface 40 Steel plate 41 Mounting hole 50 Guide guide 60 Annular recessed part 100 Welding nut

Claims (7)

  At least one flange portion is integrally provided on the outer periphery of the nut body that is threaded into the shaft and fastened to the bolt or screw, and at least three protrusions are provided on the back surface of the flange portion in a distributed manner. Features a welding nut.   The welding nut according to claim 1, wherein each protrusion provided on the back surface of the flange portion is constituted by a block body having a flat surface in part.   The welding nut according to claim 1, wherein the surface of the flange portion is formed as an inclined surface inclined downward toward the outer periphery.   The welding nut according to claim 1, wherein a guide guide having a common axis with the nut body is integrally provided on a bottom surface of the nut body.   5. The welding nut according to claim 1, wherein the guide guide protrudes longer than the flat surface of each projection provided on the back surface of the flange portion.   The welding nut according to claim 4 or 5, wherein the guide guide is formed in an annular shape. The welding nut according to claim 1, 2, 3, 4, 5 or 6, wherein an annular recess is formed between the guide guide and each protrusion provided on the back surface of the flange portion.

Images