Projection welding components

Abstract

To provide a projection welding member which can perform projection welding even on two thick steel plates to be welded at a low cost.SOLUTION: A projection welding member includes: a first joining section 11 which has an area having substantially the same size as a contact surface when a first steel plate 100 is made to abut on a second steel plate 110; a second joining section 12 which has an area of a size which comes into contact with one of two side faces 100a, 100b in a thickness direction of the first steel plate 100 when the first steel plate 100 is made to abut on the second steel plate 110; a third joining section 13 which has an area of a size which comes into contact with the other of the two side faces 100a, 100b in the thickness direction of the first steel plate 100; a first projection section 14 which comes into point contact with each of the first steel plate 100 and the second steel plate 110 in the vicinity of the second joining section 12 in the first joining section 11; and a second projection section 15 which comes into point contact with each of the first steel plate 100 and the second steel plate 110 in the vicinity of the third joining section 13 in the first joining section 11.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a projection welding member suitable for use in a resistance welding apparatus for welding a plate assembly (welded object) formed by overlapping two steel plates by sandwiching with two electrodes and energizing while applying pressure.

Background Art

[0002] Among resistance welding apparatuses, there is one called a table type in which one of the two electrodes (lower side) is fixed in a table shape and the other (upper side) is arranged in a gun shape so as to be movable up, down, left, and right. In this type of resistance welding apparatus, the welded object is sandwiched between a table electrode and a gun electrode, and welding is performed by energizing while applying pressure with the gun electrode.

[0003] By the way, in resistance welding, in order to obtain good welding, projections called projections are formed on one of the two steel plates (see, for example, Patent Document 1). Here, an example of a projection is shown in FIGS. 7 and 8. In FIG. 7, (a) is a side view of the steel plate 200, and (b) is a view of the steel plate 200 as seen from the direction of arrow J. On the steel plate 200, mountain-shaped projections 201 and 202 are formed at intervals in the longitudinal direction (arrow K direction) of the steel plate 200.

[0004] FIG. 9 is a view showing a state when the steel plate 200 and the steel plate 210 are joined. As shown in the figure, when welding the steel plate 200 and the steel plate 210, the tips of the projections 201 and 202 formed on the steel plate 200 contact at one point. In this state, by supplying current between the steel plates and applying pressure, current flows concentratedly at the locations where the projections are formed. As a result, the projections 201 and 202 are melted, and further melted over the entire contact surface between the steel plate 200 and the steel plate 210, and the steel plate 200 and the steel plate 210 are joined.

[0005] In Figure 8, (a) is a side view of the steel plate 220, and (b) is a view of the steel plate 220 from the direction of arrow M. Projections 221 and 222, each with a V-shaped cross-section, are formed on the steel plate 220, spaced apart in the longitudinal direction of the steel plate 220 (direction of arrow N). When welding the projections 221 and 222 formed on the steel plate 220 to the other steel plate 210 (see Figure 9), their respective tips come into contact at two points. In this state, by supplying current and applying pressure between the steel plates, the current flows concentrated at the locations where the projections are formed. As a result, the projections 221 and 222 melt, and further melt across the entire contact surface between the steel plate 220 and the steel plate 210, joining the steel plates 220 and 210 together.

[0006] In the example above, the projection was provided on only one steel plate of the plate assembly, but there are also cases where it is provided on the other steel plate of the plate assembly (see, for example, Patent Document 2).

[0007] Furthermore, there are also designs where projections are provided on nuts (see Patent Documents 3 and 4), and designs where projections are provided on washers (see Patent Document 5). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2001-340972 [Patent Document 2] Japanese Patent Publication No. 2002-103056 [Patent Document 3] Japanese Patent Publication No. 2013-078784 [Patent Document 4] Japanese Patent Publication No. 2004-050280 [Patent Document 5] Japanese Patent Publication No. 2016-159360 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] Incidentally, when forming projections on steel plates, as the thickness of the steel plate increases, the thickness of the projection also needs to increase, which presents the challenge of increasing the labor required for projection processing. Incidentally, in recent years, opportunities for high-mix, low-volume production have increased, and if projection processing is performed according to the thickness of the steel plate, the increase in the labor required for projection processing is directly reflected in the cost. Note that the thickness of steel plate 200 shown in Figure 7 is "L1" as shown in (b) of the same figure. Also, the thickness of steel plate 220 shown in Figure 8 is "L2" as shown in (b) of the same figure.

[0010] This invention has been made in view of the above circumstances, and aims to provide a projection welding member that enables low-cost projection welding even when the two steel plates to be welded are thick. [Means for solving the problem]

[0011] The projection welding member of the present invention is used when joining a first steel plate and a second steel plate by resistance welding, and comprises: a first joint having an area of ​​approximately the same size as the contact surface when the first steel plate is brought into contact with the second steel plate; a second joint having an area of ​​size that contacts one of the two sides of the first steel plate in the thickness direction when the first steel plate is brought into contact with the second steel plate; a third joint having an area of ​​size that contacts the other of the two sides of the first steel plate in the thickness direction when the first steel plate is brought into contact with the second steel plate; a first projection provided near the second joint of the first joint and in contact with the first steel plate and the second steel plate at least at one point; and a second projection provided near the third joint of the first joint and in contact with the first steel plate and the second steel plate at least at one point. The first joint, the second joint, the third joint, the first projection, and the second projection are integrally formed, and the first joint is positioned to fit between the first and second steel plates in a orientation that fits into the first steel plate, so that the second joint contacts one side of the first steel plate and the third joint contacts the other side of the first steel plate.

[0012] According to the above configuration, The projection welding member is positioned so that the first joint of the projection welding member fits into the first steel plate.By positioning the joint between the first and second steel plates, the second joint contacts one side of the first steel plate, and the third joint contacts the other side of the first steel plate. Furthermore, the first projection contacts the first and second steel plates at at least one point near the second joint of the first joint, and the second projection contacts the first and second steel plates at at least one point near the third joint of the first joint.

[0013] When welding the first steel plate and the second steel plate, a projection welding member with the above configuration is placed between the steel plates. Then, the first steel plate is pressed toward the second steel plate, and an electric current is passed between them. The current flowing from the first steel plate to the second steel plate is concentrated on the first and second protrusions that act as projections, causing the projection welding member to melt. Furthermore, the entire contact surface between the first and second steel plates melts, joining the first and second steel plates together.

[0014] Thus, the projection welding member of the present invention has a structure that is attached to the first steel plate and acts as a projection that joins the first steel plate and the second steel plate. Therefore, even if the steel plate to be welded is thick, by shaping it according to its thickness, projection processing is unnecessary compared to conventional methods where the steel plate itself is processed to obtain the projection, thus reducing costs. In other words, it becomes possible to perform welding by projection at a low cost. [Brief explanation of the drawing]

[0015] [Figure 1] Perspective view showing the appearance of a projection welding member according to one embodiment of the present invention. [Figure 2] Figure 1 shows the projection welded member as viewed from the direction of arrow A. [Figure 3] Figure 1 shows a longitudinal section of the BB line of the projection welded member. [Figure 4] A perspective view showing the appearance of a modified example of a projection welding member according to one embodiment of the present invention. [Figure 5] Figure 4 shows the projection welded member viewed from the direction of arrow E. [Figure 6] Vertical cross-sectional view of the projection welding member of FIG. 4 taken along line F-F [Figure 7] (a), (b) Figures for explaining conventional projections [Figure 8] (a), (b) Figures for explaining other conventional projections [Figure 9] Figure showing the state of welding using the conventional projection shown in FIG. 7 [Figure 10] Side view showing the appearance of the resistance welding apparatus

Mode for Carrying Out the Invention

[0016] Before explaining one embodiment of the projection welding member of the present invention, an example of a resistance welding apparatus used for resistance welding will be described.

[0017] FIG. 10 is a side view showing the appearance of a resistance welding apparatus 500 developed by the present inventors etc. In the figure, the resistance welding apparatus 500 includes a welding gun in a vertical posture (hereinafter referred to as "vertical gun") 502, a table electrode 503, a column 513, a support arm 514, a pedestal 515, a welding transformer 516, a power supply cable 517, and a control device 518.

[0018] The vertical gun 502 includes a shank holder 505, a crankshaft 506, a gun shaft 507, a gun holder 508, a handle 509, a pressurizing device 510, and a power supply device 511. An electrode 540 is attached to the shank holder 505 via a shank 530. The shank holder 505, the crankshaft 506, and the gun shaft 507 are each formed of a cylindrical rod shape made of a metal material (mainly copper) having conductivity. The gun shaft 507 is inserted into the gun holder 508. The gun holder 508 is supported by the support arm 514.

[0019] The vertical gun 502 is supported so as to be able to move up and down perpendicular to the planar direction of the table electrode 503, and also so as to be able to move in the planar direction of the table electrode 503. The vertical gun 502 is also held in a state where it is lifted up with a constant tension by a lifting mechanism 520 disposed at the tip of the support arm 514. The action of the lifting mechanism 520 allows the vertical gun 502 to be fixed in any position in the vertical direction. The vertical gun 502 is also able to rotate about the axis of the gun holder 508.

[0020] The gun holder 508 is cylindrical and rod-shaped, positioned perpendicular to the arm direction of the support arm 514 on the underside of the tip of the support arm 514. The gun shaft 507 is inserted into the gun holder 508. The handle 509 is used to operate the vertical gun 502. Specifically, by operating the handle 509, the vertical gun 502 can be rotated and moved up and down. The handle 509 is equipped with a push-button type start switch (not shown), and by operating this start switch, a welding command is output to the control device 518.

[0021] The pressurizing device 510 is positioned on the upper surface of the tip of the support arm 514. The pressurizing device 510 pressurizes the gun shaft 507 downward (towards the table electrode 503), and when compressed air is supplied during welding, it grips the gun shaft 507 and pushes it downward (towards the table electrode 503).

[0022] The power supply unit 511 supplies power from the welding transformer 516 to the vertical gun 502. The power supply unit 511 has two built-in contacts (not shown), which become contacted (on) or not contacted (off) depending on the injection and discharge of air from the outside. The power supply unit 511 is turned on during welding by the control device 518. When the power supply unit 511 is turned on, power from the welding transformer 516 is supplied to the vertical gun 502.

[0023] The table electrode 503 is formed from a conductive metal material (mainly copper) into a roughly square, flat plate shape. The table electrode 503 is positioned below the vertical gun 502, perpendicular to the height direction of the main body of the equipment. A metal workpiece (for example, two steel plates, not shown) is placed on the table electrode 503. The stand 515 is a platform used for welding work, and the table electrode 503 is placed on this stand 515.

[0024] The welding transformer 516 supplies power to the vertical gun 502. One electrode (not shown) is connected to the table electrode 503, and the other electrode (not shown) is connected to the power supply device 511 via a power supply cable 517 or the like. The welding transformer 516 is built into the frame 515.

[0025] The support arm 514 is positioned at the upper end of the column 513 in the direction of vertical installation, perpendicular to the direction of vertical installation of the column 513. The support arm 514 has a multi-joint structure that allows for horizontal rotation with the connection point with the column 513 as the pivot point. The control device 518 receives a welding command from the operation of a start switch (not shown) located on the vertical gun 502 and applies pressure and power to the vertical gun 502. Specifically, upon receiving a welding command, the control device 518 activates the pressure device 510 to pressurize the vertical gun 502 toward the table electrode 503, and also turns on the power supply device 511 to supply power to the vertical gun 502.

[0026] The resistance welding apparatus 500 is equipped with a cooling unit (not shown), which cools the cooling water circulating inside the resistance welding apparatus 500. The vertical gun 502 and power supply cable 517, etc., have a structure for circulating the cooling water.

[0027] In a resistance welding apparatus 500 with this configuration, the start switch is operated while the electrode 540 attached to the tip of the vertical gun 502 is in contact with the welding point of the workpiece (not shown) placed on the table electrode 503. This activates the pressurizing device 510, pushing the gun shaft 507 toward the workpiece (not shown). At the same time, power is supplied from the power supply unit (not shown) to the welding transformer 516, and the power generated on the secondary side of the welding transformer 516 is applied between the vertical gun 502 and the table electrode 503. This allows welding to be performed on the workpiece (not shown). If a projection is formed on the workpiece (not shown) at this time, current flows through the projection.

[0028] Next, one embodiment of the present invention will be described in detail with reference to the drawings. Figure 1 is a perspective view showing the appearance of a projection welding member 10 according to one embodiment of the present invention. Figure 2 is a view of the projection welding member 10 of Figure 1 from the direction of arrow A. Figure 3 is a longitudinal cross-sectional view of the projection welding member 10 of Figure 1 along line BB.

[0029] In Figures 1 to 3, the projection welding member 10 is used when joining the first steel plate (workpiece to be welded, see Figure 3) 100 and the second steel plate (workpiece to be welded, see Figure 3) 110 by resistance welding.

[0030] The projection welding member 10 has a first joint 11 having an area approximately the same size as the area of ​​the first steel plate 100 (the area obtained by multiplying the length in the C direction and the length in the D direction shown in Figure 1), and a second joint 12 having an area large enough to contact one of the two side surfaces 100a and 100b of the first steel plate 100 in the thickness direction (C direction shown in Figure 3) (side surface 100a) when the first steel plate 100 is brought into contact with the second steel plate 110, and when the first steel plate 100 is brought into contact with the second steel plate 110 The first steel plate 100 comprises a third joint portion 13 having an area large enough to contact the other side (side 100b) of the two side surfaces 100a and 100b in the thickness direction (C direction as described above), a first projection 14 near the second joint portion 12 of the first joint portion 11 that contacts the first steel plate 100 and the second steel plate 110 at one point, and a second projection 15 near the third joint portion 13 of the first joint portion 11 that contacts the first steel plate 100 and the second steel plate 110 at one point. These members, namely the first joint portion 11, the second joint portion 12, the third joint portion 13, the first projection 14, and the second projection 15, are integrally molded.

[0031] The second joint 12 contacts the side surface 100a (see Figure 3) of the first steel plate 100 with its inner surface 12a (see Figure 2), and the third joint 13 contacts the side surface 100b (see Figure 3) of the first steel plate 100 with its inner surface 13a (see Figure 2). The second joint 12 and the third joint 13 support the first steel plate 100. As can be seen from the longitudinal cross-sectional view in Figure 3, the first projection 14 and the second projection 15 have a cross-section shaped like an abacus bead. The upper vertices of the first projection 14 and the second projection 15 contact the bottom surface 100c of the first steel plate 100, and the lower vertices of the first projection 14 and the second projection 15 contact the top surface 110a of the second steel plate 110.

[0032] The material used for the projection welded member 10 is the same as the material used for the first steel plate 100 and the second steel plate 110. For example, it is an iron-based material or a stainless steel-based material that has rigidity and conductivity. Incidentally, copper is not very suitable because it is difficult to melt. Also, magnesium is not very suitable due to safety concerns.

[0033] When joining the first steel plate 100 and the second steel plate 110 by resistance welding, a projection welding member 10 having a first joint portion 11 of a size corresponding to the thickness of the first steel plate 100 is used and placed between the first steel plate 100 and the second steel plate 110. At this time, the width direction (D direction) of the first joint portion 11 is positioned parallel to the width direction of the first steel plate 100. By placing the projection welding member 10 between the first steel plate 100 and the second steel plate 110, the inner surface 12a of the second joint portion 12 contacts one side surface 100a of the first steel plate 100, and the inner surface 13a of the third joint portion 13 contacts the other side surface 100b of the first steel plate 100.

[0034] Furthermore, the first projection 14 contacts the first steel plate 100 and the second steel plate 110 respectively near the second joint 12 of the first joint 11, and the second projection 15 contacts the first steel plate 100 and the second steel plate 110 respectively near the third joint 13 of the first joint 11.

[0035] In this manner, the projection welding member 10 is attached to the first steel plate 100 and placed against the joining position of the second steel plate 110. It is preferable to perform this assembly on the table electrode 503 of the resistance welding apparatus 500. After this assembly is completed, the electrode 540 is placed against the first steel plate 100. In this state, by operating the push-button type start switch (not shown) located on the handle 509 of the vertical gun 502, the control device 518 of the resistance welding apparatus 500 receives a welding command from the start switch and activates the pressurizing device 510, which pressurizes the vertical gun 502 toward the table electrode 503, and further turns on the power supply device 511 to allow current to flow between the first steel plate 100 and the second steel plate 110.

[0036] The current flowing from the first steel plate 100 to the second steel plate 110 is concentrated on the first projection 14 and the second projection 15 of the projection welding member 10, causing the projection welding member 10 to melt, and further melting across the entire contact surface between the first steel plate 100 and the second steel plate 110, thereby joining the first steel plate 100 and the second steel plate 110.

[0037] Thus, according to the projection welding member 10 of this embodiment, it has a structure that is attached to the first steel plate 100 and acts as a projection that joins the first steel plate 100 and the second steel plate 110. Therefore, even if the steel plate to be welded is thick, by shaping it according to its thickness, projection processing is unnecessary compared to conventional methods that process the steel plate itself to obtain a projection, thus reducing costs. In other words, it becomes possible to perform welding by projection at a low cost.

[0038] In this embodiment of the projection welding member 10, the first projection 14 is positioned near the second joint 12 and the second projection 15 is positioned near the third joint 13, but it is not necessary to position them in this manner.

[0039] Furthermore, in the projection welding member 10 of this embodiment, the first projection 14 is configured to contact the first steel plate 100 and the second steel plate 110 at one point each, but it may also be configured to contact at multiple points. That is, it is sufficient for it to contact at least one point. The same applies to the second projection 15, which may also be configured to contact the first steel plate 100 and the second steel plate 110 at multiple points each.

[0040] Furthermore, in the projection welding member 10 of this embodiment, the first projection 14 and the second projection 15 constituting the projection welding member 10 are each shaped like an abacus bead in cross-section, but the shape is not limited to an abacus bead in cross-section as long as a similar effect can be obtained. A modified example of the projection welding member 10 will be described below. This modified example of the projection welding member will be referred to as the projection welding member 20.

[0041] Figure 4 is a perspective view showing the external appearance of the projection welding member 20. Figure 5 is a view of the projection welding member 20 of Figure 4 from the direction of arrow E. Figure 6 is a longitudinal cross-sectional view of the projection welding member 20 of Figure 4 along the FF line. Note that the projection welding member 20 has the same shape as the projection welding member 10, except for the shape of the parts that come into contact with the first and second steel plates 100 and 110, so only the contact parts will be described.

[0042] In Figures 4 to 6, the first projection 24 contacts the first steel plate 100 and the second steel plate 110 respectively near the second joint 22 of the first joint 21. The second projection 25 contacts the first steel plate 100 and the second steel plate 110 respectively near the third joint 23 of the first joint 21.

[0043] The second joint 22 contacts the side surface 100a (see Figure 6) of the first steel plate 100 with its inner surface 22a (see Figure 5). The third joint 23 contacts the side surface 100b (see Figure 6) of the first steel plate 100 with its inner surface 23a (see Figure 5). The second joint 22 and the third joint 23 support the first steel plate 100. As can be seen from the longitudinal cross-sectional view in Figure 6, the first projection 24 and the second projection 25 have a roughly S-shaped cross-section. Specifically, the first projection 24 (second projection 25) is formed in an S-shape, comprising a convex portion 24a (25a) that contacts the bottom surface 100c of the first steel plate 100, and a convex portion 24b (25b) that is spaced apart from the convex portion 24a (25a) and contacts the upper surface 110a of the second steel plate 110.

[0044] When joining the first steel plate 100 and the second steel plate 110 by resistance welding, a projection welding member 20 having a first joint portion 21 of a size corresponding to the thickness of the first steel plate 100 is used and placed between the first steel plate 100 and the second steel plate 110. At this time, the width direction of the first joint portion 21 is positioned parallel to the width direction of the first steel plate 100. By placing the projection welding member 20 between the first steel plate 100 and the second steel plate 110, the inner surface 22a of the second joint portion 22 contacts one side surface 100a of the first steel plate 100, and the inner surface 23a of the third joint portion 23 contacts the other side surface 100b of the first steel plate 100.

[0045] Furthermore, the first projection 24 contacts the first steel plate 100 and the second steel plate 110 respectively near the second joint 22 of the first joint 21, and the second projection 25 contacts the first steel plate 100 and the second steel plate 110 respectively near the third joint 23 of the first joint 21.

[0046] In this manner, the projection welding member 20 is attached to the first steel plate 100 and placed against the joining position of the second steel plate 110. After this assembly, the electrode 540 is applied to the first steel plate 100. In this state, by operating the push-button type start switch (not shown) located on the handle 509 of the vertical gun 502, the control device 518 of the resistance welding apparatus 500 receives a welding command from the start switch and activates the pressurizing device 510, pressurizing the vertical gun 502 toward the table electrode 503, and further turning on the power supply device 511 to allow current to flow between the first steel plate 100 and the second steel plate 110.

[0047] The current flowing from the first steel plate 100 to the second steel plate 110 is concentrated on the first projection 24 and the second projection 25 of the projection welding member 20, causing the projection welding member 20 to melt, and further melting across the entire contact surface between the first steel plate 100 and the second steel plate 110, thereby joining the first steel plate 100 and the second steel plate 110.

[0048] Thus, according to the projection welding member 20 of this embodiment, it has a structure that is attached to the first steel plate 100 and acts as a projection that joins the first steel plate 100 and the second steel plate 110. Therefore, even if the steel plate to be welded is thick, by shaping it according to its thickness, projection processing is unnecessary compared to conventional methods where the steel plate itself is processed to obtain the projection, thus reducing costs. In other words, it becomes possible to perform welding by projection at a low cost.

[0049] Although the present invention has been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. [Industrial applicability]

[0050] The present invention can be applied to a resistance welding apparatus that welds a plate assembly, made by overlapping two steel plates, by sandwiching it between two electrodes and applying pressure while passing an electric current through it. [Explanation of Symbols]

[0051] 10,20 Projection welding components 11,21 1st joint 12,22 2nd joint 13,23 Third joint 14,24 1st protrusion 15,25 2nd protrusion 100 1st steel plate 110 Second steel plate 500 resistance welding equipment 502 Vertical Gun 503 Table Electrode 509 Handle 518 Control Device 510 Pressurizing device 511 Power supply device 540 electrode

Claims

[Claim 1] Used when joining the first steel plate and the second steel plate by resistance welding. A first joint having an area approximately the same size as the contact surface when the first steel plate is brought into contact with the second steel plate, A second joint having an area that contacts one of the two sides of the first steel plate in the thickness direction when the first steel plate is brought into contact with the second steel plate, A third joint having an area that contacts the other of the two sides of the first steel plate in the thickness direction when the first steel plate is brought into contact with the second steel plate, A first projection is provided near the second joint of the first joint and contacts the first steel plate and the second steel plate at at least one point, A second projection is provided near the third joint of the first joint and contacts the first steel plate and the second steel plate at at least one point, Equipped with, The first joint, the second joint, the third joint, the first projection, and the second projection are integrally formed. The first joint is positioned to fit into the first steel plate and to be inserted between the first and second steel plates, so that the second joint contacts one side of the first steel plate and the third joint contacts the other side of the first steel plate. Projection welding components.

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